Corso aaroi besity intubation

OBESITY AND INTUBATION
Sottogruppo del file
principale

Perché intubare e ventilare?
Perché non lasciare in respiro spontaneo?
• 1
• Perché la curva CO2/risposta ventilatoria è
spostata a dx….
• Respir Care. 2010 Nov;55(11):1442-8..Hypercapnic respiratory failure in obesity-
hypoventilation syndrome: CO₂ response and acetazolamide treatment effects.Raurich JM,
Rialp G, Ibáñez J, Llompart-Pou JA, Ayestarán I.
• Intensive Care Unit, Hospital Universitari Son Dureta, Andrea Doria 55, 07014, Palma de Mallorca, Illes Balears, Spain. joan.raurich@ssib.es
• Comment in:
• Respir Care. 2010 Nov;55(11):1504-5.
• Abstract
• OBJECTIVE: In obesity-hypoventilation-syndrome patients mechanically ventilated for hypercapnic respiratory failure we investigated the relationship between CO₂ response, body mass
index, and plasma bicarbonate concentration, and the effect of acetazolamide on bicarbonate concentration and CO₂ response.
• METHODS: CO₂ response tests and arterial blood gas analysis were performed in 25 patients ready for a spontaneous breathing test, and repeated in a subgroup of 8 patients after
acetazolamide treatment. CO₂ response test was measured as (1) hypercapnic drive response (the ratio of the change in airway occlusion pressure 0.1 s after the start of inspiratory flow
to the change in P(aCO₂)), and (2) hypercapnic ventilatory response (the ratio of the change in minute volume to the change in P(aCO₂)).
• RESULTS: We did not find a significant relationship between CO₂ response and body mass index. Patients with higher bicarbonate concentration had a more blunted CO₂ response.
Grouping the patients according to the first, second, and third tertiles of the bicarbonate concentration, the hypercapnic drive response was 0.32 ± 0.17 cm H₂O/mm Hg, 0.22 ± 0.15 cm
H₂O/mm Hg, and 0.10 ± 0.06 cm H₂O/mm Hg, respectively (P = .01), and hypercapnic ventilatory response was 0.46 ± 0.23 L/min/mm Hg, 0.48 ± 0.36 L/min/mm Hg, and 0.22 ± 0.16
L/min/mm Hg, respectively (P = .04). After acetazolamide treatment, bicarbonate concentration was reduced by 8.4 ± 3.0 mmol/L (P = .01), and CO₂ response was shifted to the left, with
an increase in hypercapnic drive response, by 0.14 ± 0.16 cm H₂O/mm Hg (P = .02), and hypercapnic ventilatory response, by 0.11 ± 0.22 L/min/mm Hg (P = .33).
• CONCLUSIONS: Patients with obesity-hypoventilation syndrome and higher bicarbonate concentrations had a more blunted CO₂ response. Body mass index was not related to CO₂
response. Acetazolamide decreased bicarbonate concentration and increased CO₂ response

Airway-occlusion pressure 0.1 s after the start of inspiratory flow (P0.1) versus
PaCO2, and minute volume (V˙ E) versus PaCO2,grouped according to the tertiles
of BMI BMI tertile values were: first tertile 30–36 kg/m2, second tertile
36–42 kg/m2, third tertile 42–60 kg/m2.
The first-tertile data points are indicated with squares. The second-tertile data points are indicated
with circles. The third-tertile data points are indicated with triangles. The error bars represent sSE

Collassibilità dello spazio
retroglottico,sup e inf
• 2
• severity of apnea in the obese group may be
have been due to increased collapsibility of
the upper airway rather than decreased size
of the upper airway
– polysomnography, cephalometry and dynamic multi-
detector computerized tomography (MD-CT) in wake
and sleep states according to obesity.
• Clin Exp Otorhinolaryngol. 2010 Sep;3(3):147-52. Epub 2010
Sep 17.Differences of Upper Airway Morphology According
to Obesity: Study with Cephalometry and Dynamic MD-
CT.Kim TH, Chun BS, Lee HW, Kim JS

high retropalatal (HRP), low retropalatal (LRP), high retroglossal (HRG), and low
retroglossal (LRG). A minimal cross sectional area (mCSA) and collapsibility index (CI)

INTRODUCTION
• Excellent intubating conditions are imperative for
direct laryngoscopy and the efficient placement of a
tracheal tube.
• The proper positioning of a patient before
induction is a key step.
• Classic teaching has been to position the patient
in the "sniffing" position, or supine with
moderate head elevation and atlanto-occipital
extension.
– Bannister FB, Macbeth RG. Direct laryngoscopy and tracheal intubation. Lancet 1944;244, 6325:651–4

CRITERI PREDITTIVI;APPLICATI AGLI
OBESI….

Non è che dobbiamo rivedere i criteri
di valutazione esterni delle vie aeree?
• Vedi articolo di Laryngoscope :
• Clinical Predictors of Difficult
Laryngeal Exposure

Ming-Wang Hsiung, Lu Pai, Bor-Hwang Kang, Bing-Long Wang,
Chih-Shung Wong, Hsing-Won Wang, Clinical Predictors of Difficult
Laryngeal Exposure.Laryngoscope, 114:358-363, 2004
• difficult laryngeal exposure following rigid laryngoscopy:predictors of DLE ?
• 56 pts :a physical examination with age, sex, modified Mallampati index
(MMI),body mass index (BMI), hyoid-mental distance (HMD),thyroid-mental
distance (TMD), thyroid-mandible angle (TMA), horizontal thyroid distance
(HTD), and vertical thyroid distance (VTD)
• Stepwise regression employed on patient data to identify those with DLE.
• sex (P = .045,odds ratio = 69.159) and TMA (P = .004, odds ratio =1.510) to be
"reliable" DLE predictors.
• Using these 2 variables, 94.6% of study case patients could have been
correctly classified preoperatively. Based on our comparison of case results,
we found that a TMA value >120 degrees in men and 130
degrees in women indicates a strong likelihood of DLE.

Hyoid mental distance (HMD) and thyroid mental distance
(TMD)

Vertical thyroid distance (VTD)and horizontal thyroid
distance(HTD)

TMA can be regarded as a
composite of the tongue,
mandible,and epiglottis
during a rigid
laryngoscope procedure.
Tiroid mandible angle:TMA

Preoperative airway assessment:
predictive value of a multivariate risk
index
• Anesth Analg. 1996 Jun;82(6):1197-204..
• el-Ganzouri AR, McCarthy RJ, Tuman KJ, Tanck EN, Ivankovich AD.
• Source
• Department of Anesthesiology, Rush-Presbyterian-St. Luke's Medical Center at Rush Medical College, Chicago, Illinois 60612, USA.
• 10,507 consecutive patients
• prospectively assessed prior to general anesthesia with respect to
• mouth opening, thyromental distance, oropharyngeal (Mallampati) classification, neck
movement, ability to prognath, body weight, and history of difficult tracheal intubation.
• After induction of anesthesia, the laryngeal view during rigid laryngoscopy was
graded and the ability of experienced anesthesia personnel to ventilate via a mask
was determined.
• Poor intubating conditions (laryngoscopy Grade IV) and inability to achieve
adequate mask ventilation were identified in 107 (1%) and 8 (0.07%)
cases, respectively.
• Logistic regression identified all seven criteria as independent predictors of difficulty with laryngoscopic visualization.
• A composite airway risk index (derived from nominalized odds ratios calculated from the multivariate model) as well a simplified (0 = low, 1 =
medium, 2 = high) risk weighting exhibited higher positive predictive value for laryngoscopy Grade IV at scores with similar sensitivity to Mallampati
class III, as well as higher sensitivity at scores with similar positive predictive value. Compared to Mallampati class I fewer false-negative predictions
were observed at a risk index value of 0. We conclude that improved risk stratification for difficulty with visualization during rigid laryngoscopy
(Grade IV) can be obtained by use of a simplified preoperative multivariate airway risk index, with better accuracy compared to oropharyngeal
(Mallampati) classification at both low- and high-risk levels.

SAR:
(simplified airway risk index,SAR index)
Described by El-Ganzouri et al.:
El-Ganzouri AR, McCarthy RJ, Tuman KJ, et al. Preoperative airway assessment: predictive value of a multivariate
risk index. Anesth Analg 1996;82:1197–204
• assigned a value of 0,1, or 2 to the following risk
factors:
– MO (>35 mm, 0;<35 mm, 1),
– TMD (>65 mm, 0; 60–65 mm, 1; <60 mm,2),
– Mallampati score (I, 0; II, 1; III or IV, 2),
– Cervical spine extension (90°, 0; 80°–90°, 1; 80°, 2),
– body weight (90 kg, 0; 90–110 kg, 1; 110 kg, 2),
– history of difficult intubation (none, 0; questionable,
1;definite, 2).
• A SAR score 4 categorized the patient as at
risk for difficult intubation

Prediction of difficult tracheal intubation
• Iohom G, Ronayne M, Cunningham AJ.Eur J Anaesthesiol. 2003
Jan;20(1):31-6.
• .
• Source
• Beaumont Hospital, Department of Anaesthesia and Intensive Care, Dublin, Ireland. iohom@hotmail.com
• Abstract
• BACKGROUND AND OBJECTIVE:
• Preoperative bedside screening tests for difficult tracheal intubation may be neither sensitive nor specific enough for clinical use. The aim was to
investigate if a combination of the Mallampati classification of the oropharyngeal view with either the thyromental or sternomental distance
measurement improved the predictive value.
• METHODS:
• A total of 212 (109 male, 103 female) non-obstetric surgical patients, aged >18 yr, undergoing elective surgical procedures requiring tracheal
intubation were assessed preoperatively with respect to the oropharyngeal (modified Mallampati) classification, thyromental and sternomental
distances. An experienced anaesthetist, blinded to the preoperative airway assessment, performed laryngoscopy and graded the view according to
Cormack and Lehane's classification.
• RESULTS:
• Twenty tracheal intubations (9%) were difficult as defined by a Cormack and Lehane Grade 3 or 4, or the requirement for a bougie in patients with
Cormack and Lehane Grade 2. Used alone, the Mallampati oropharyngeal view, and thyromental and sternomental distances were associated with
poor sensitivity, specificity and positive predictive values. Combining the Mallampati Class III or IV with either a thyromental distance <6.5cm or a
sternomental distance <12.5cm decreased the sensitivity (from 40 to 25 and 20%, respectively), but maintained a negative predictive value of 93%.
The specificity and positive predictive values increased from 89 and 27% respectively for Mallampati alone to 100%.
• CONCLUSIONS:
• The findings suggest that the Mallampati classification, in conjunction with measurement of
the thyromental and sternomental distances, may be a useful routine screening
test for preoperative prediction of difficult tracheal intubation

Predicting Difficult Intubation in Apparently Normal Patients.A Meta-analysis of Bedside
Screening Test Performance

Anesth Analg. 2009 Dec;109(6):1870-80.Difficult
mask ventilation.El-Orbany M, Woehlck HJ.
• Mask ventilation is the most fundamental skill in
airway management. I
• n this review, we summarize the current knowledge about difficult mask ventilation (DMV)
situations. Various definitions for DMV have been used in the literature. The lack of a precise
standard definition creates a problem for studies on DMV and causes confusion in data
communication and comparisons. DMV develops because of multiple factors that are technique
related and/or airway related. Frequently, the pathogenesis involves a combination of these factors
interacting to cause the final clinical picture. The reported incidence of DMV varies widely (from
0.08% to 15%) depending on the criteria used for its definition. Obesity, age older than 55 yr,
history of snoring, lack of teeth, the presence of a beard, Mallampati Class III or IV, and abnormal
mandibular protrusion test are all independent predictors of DMV. These signs should, therefore,
be recognized and documented during the preoperative evaluation. DMV can be even more
challenging in infants and children, because they develop hypoxemia much faster than adults.
Finally, difficult tracheal intubation is more frequent in patients who experience DMV, and thus,
clinicians should be familiar with the corrective measures and management options when faced
with a challenging, difficult, or impossible mask ventilation situation

Definition of difficult mask ventilation
(DMV)
• 1993, ASA Task Force on Management of the
Difficult Airway :
• “DMV is a situation that develops when it is
not possible for the unassisted
anesthesiologist to maintain the oxygen
saturation 90% using 100% oxygen and
positive pressure ventilation, or to prevent or
reverse signs of inadequate ventilation.”

Studies on difficult mask ventilation:1
• prospective study of 1502 patients, multivariate analysis of
preoperative findings that were correlated with DMV. They found
5 risk factors to be significantly associated with DMV and thus
may be used as predictors. These were:
• age > 55 yr
• body mass index (BMI)> 26 kg/m2
• lack of teeth
• history of snoring,
• presence of a beard.
• The presence of at least t 2 of these factors indicated a high
likelihood of DMV.
– Langeron O, Masso E, Huraux C, Guggiari M, Bianchi A, Coriat P, Riou B. Prediction of
difficult mask ventilation. Anesthesiology 2000;92:1229–36

Studies on difficult mask ventilation:2 e 3
• age,
• Weight
• history of snoring
• male gender
• Mallampati Class IV
• significantly associated with DMV.
– Yildiz TS, Solak M, Toker K. The incidence and risk factors of difficult mask ventilation. J
Anaesth 2005;19:7–11
• multivariate regression analysis:independent predictors for Grade 3 MV (DMV).
• age > than 57 yr,
• BMI > 30,
• history of snoring
• the presence of a beard,
• Mallampati Class III or IV,
• limited mandibular protrusion test
• In contrast, however, they were not able to identify lack of teeth as a predictor. They also
identified history of snoring and thyromental distance of 6 cm as predictors of Grade 4 MV
(IMV).
– . Kheterpal S, Han R, Tremper KK, Shanks A, Tait AR, O’Reilly,M, Ludwig TA. Incidence and
predictors of difficult and impossible mask ventilation. Anesthesiology 2006;105:885–91

Anesthesiology. 2006 Nov;105(5):885-91.
Incidence and predictors of difficult and impossible mask ventilation.
Kheterpal S, Han R, Tremper KK, Shanks A, Tait AR, O'Reilly M, Ludwig
TA.
• 4 point scale to grade difficulty in performing mask ventilation (MV)
:
– grade 3 MV =(inadequate, unstable, or requiring two providers)
– grade 4 MV (impossible to ventilate)
– difficult intubation.
During a 24-month period, 22,660 attempts at MV
313 cases (1.4%) of grade 3 MV, 37 cases (0.16%) of grade 4 MV, and 84
cases (0.37%) of grade 3 or 4 MV and difficult intubation
• CONCLUSIONS:
• The authors observed the incidence of grade 3 MV to be 1.4%,
similar to studies with the same definition of difficult MV. Presence
of a beard is the only easily modifiable independent risk factor for
difficult MV. The mandibular protrusion test may be an essential
element of the airway examination

Risultati dallo studio di Ketherpal et al :
• Predictors of grade 3 mask ventilation:
• Body mass index of 30 kg/m or greater
• a beard,
• Mallampati classification III or IV,
• age of 57 yr or older,
• severely limited jaw protrusion,
• Snoring
• Predictors of grade 4 mask ventilation:
• Snoring
• thyromental distance <6 cm
• predictors of grade 3 or 4 MV and difficult intubation
• Limited or severely limited mandibular protrusion
• abnormal neck anatomy,
• sleep apnea,
• snoring,
• body mass index of 30 kg/m or greater

Conclusioni sulla difficile ventilazione
in maschera:
• Tutti gli autori concordano che:
• BMI>30
• Mallampati 3 e 4
• Russamento
• Sono tutti predittivi!e quindi tutti gli
obesi presentano potenzialmente
questo problema!

Methods to secure airway in Obese
patients:
• Intubation after induction
• Awake fibreoptic intubation
• Various Laryngeal mask airways (LMAs)
• LMA-fastrach
• LMA Ctrach
• Glidescope
• AirtraqTM laryngoscope
• Etc….

• Several reviews have reported that endotracheal
intubation is more difficult in obese than in lean
patients .
• However, this assertion remains debated because
others studies have found no evidence that
tracheal intubation is more difficult in obese than
in lean individuals .
• One of the reasons for these discrepancies is the
lack of consensus on the definition of the term
“difficult intubation,” which varies between
authors.

Obese pts are more difficult to
intubate?
• Yes:
• Benumof JL. Management of the difficult adult airway: with special emphasis on awake tracheal intubation.
Anesthesiology 1991;75:1087–110.
• Adams JP, Murphy PG. Obesity in anaesthesia and intensive care. Br J Anaesth 2000;85:91–108.
• Fox GS, Whalley DG, Bevan DR. Anaesthesia for the morbidly obese: experience with 110 patients. Br J
Anaesth 1981;53:811–6.
• Shenkman Z, Shir Y, Brodsky JB. Perioperative management of the obese patient. Br J Anaesth 1993;70:349–
59.
• Voyagis GS, Kyriakis KP, Dimitriou V, Vrettou I. Value of oropharyngeal Mallampati classification in predicting
difficult laryngoscopy among obese patients. Eur J Anaesthesiol 1998;15:330–4.
• Wilson ME, Spiegelhalter D, Robertson JA, Lesser P. Predicting difficult intubation. Br J Anaesth 1988;61:211–
6.
• YES/NO
• Lavi R, Segal D, Ziser A. Predicting difficult airways using the intubation difficulty scale: a study comparing
obese and non-obese patients. J Clin Anesth. 2009 Jun;21(4):264-7.;IDS score higher in obese,but duration of
intubation =
• NO:
• Karkouti K, Rose DK, Wigglesworth D, Cohen MM. Predicting difficult intubation: a multivariable
analysis. Can J Anaesth 2000;47:730–9.
• Brodsky JB, Lemmens HJ, Brock-Utne JG, et al. Morbid obesity and tracheal intubation. Anesth
Analg 2002;94:732–6.
• Bond A. Obesity and difficult intubation. Anaesth Intensive Care 1993;21:828–30.

The Association Between Obesity and Difficult
Prehospital Tracheal Intubation
• Timothy J. Holmberg, Stephen M. Bowman, Keir J. Warner,Monica S. Vavilala,Eileen M.
Bulger,Michael K. Copass, Sam R. Sharar,.
• retrospective review
• all patients ≥15 years of age who underwent prehospital trch.intub by paramedics
• Seattle Medic One system over a 4-year period,
• Pts transported to the regional level 1 trauma center (Harborview Medical Center)
• Data were abstracted from a prospectively collected prehospital airway management database and
from the hospital medical records, including demographic information, number of TI attempts, TI
success or failure, and body weight/height (BMI).
• RESULTS: Of 80,501 patient contacts in whom 4114 TIs were attempted during the 4-year study
period, 823 met study entry criteria (including a calculable BMI). The overall TI success rate in the
study population was 98.5% (811 out of 823), with 6.8% (56 out of 823) meeting the predetermined
definition for difficult TI. There was no significant association between difficult TI and patient age,
gender, use of succinylcholine, or medical diagnosis (trauma vs. nontrauma).
• In comparison with the lean patient subgroup (BMI <30 kg/m2), patients with class III obesity
(BMI >40 kg/m2) had a significant association with difficult TI (odds ratio 3.68; confidence interval
[CI] 1.27–10.59), whereas those with class I/II obesity (BMI ≥30 kg/m2 and <40 kg/m2) did not
(odds ratio 0.98; CI 0.46 –2.07).
• CONCLUSIONS: Among prehospital ALS providers with previously documented and published
successful TI performance, increased difficulty with TI was observed in patients with extreme
obesity, but not in patients with lesser degrees of obesity. Because extreme obesity is an easily
identifiable patient characteristic, didactic and clinical (e.g., operating room) airway management
education for such providers should emphasize airway management challenges and strategies
associated with obesity, including specific equipment, patient positioning, and practice
recommendations that may facilitate both TI and alternative airway management techniques in this
population.

Casistica retrospettiva Memorial
Hospital Houston,Texs
• 283 obese patients:
• Fibrobroncoscopia + frequente in:
• BMI > or = 60 kg/m2 (P < 0.001)
• Mallampati class III or IV airway (P < 0.001)
• Male (P = 0.004).
• These three factors were also statistically significant in the
multivariate logistic regression. In particular, each one kg/m(2)
increase in BMI was associated with a 7% increased likelihood of
AFI. Men were approximately 4 times likelier than women to have
an AFI. Compared with patients with a Mallampati Class I or II
airway, those with Mallampati Classes III or IV were about 26 times
as likelier to have an AFI.
• No failed intubations

PER ES,ANCHE UNA
METANALISI…….

Shiga T, Wajima Z, Inoue T, Sakamoto A: Predicting difficult intubation
in apparently normal patients: A meta-analysis of bedside screening
test performance.ANESTHESIOLOGY 2005; 103:429–37
• to systematically determine the diagnostic accuracy of bedside tests for predicting difficult intubation
in patients with no airway pathology
• Thirty-five studies (50,760 patients) were selected from electronic databases.
• overall incidence of difficult intubation was 5.8% (95% confidence interval, 4.5-7.5%).
• Screening tests included the Mallampati oropharyngeal classification, thyromental distance,
sternomental distance, mouth opening, and Wilson risk score.
• Each test yielded poor to moderate sensitivity (20-62%) and moderate to fair specificity (82-97%).
• The most useful bedside test for prediction was found to be a combination of the Mallampati
classification and thyromental distance (positive likelihood ratio, 9.9; 95% confidence interval, 3.1-
31.9).
• Currently available screening tests for difficult intubation have
only poor to moderate discriminative power when used alone.
Combinations of tests add some incremental diagnostic value
in comparison to the value of each test alone. The clinical
value of bedside screening tests for predicting difficult
intubation remains limited(vedi la diapo precedente)
• Obese subgroup:obese patients are three times more
difficult to intubate than their slimmer counterparts.

La loro asserzione finale è smentita
dall’analisi dei lavori che essi stessi
hanno citato…..
• 378 patients in the studies they reviewed, and
every patient except one was intubated
successfully by direct laryngoscopy.
• All 4 of the studies they analyzed specifically
stated that the magnitude of obesity does not
influence laryngoscopy difficulty.

Punti da chiarire :
• 1)Difficult laryngoscopy is not synonimous of
difficult intubation
• 2)ASA Task Force on the management of the
difficult airway defines a difficult airway”
• as the “clinical situation in which a
conventionally trained anesthesiologist
experiences problems with (a) face mask
ventilation of the upper airway or (b)
tracheal intubation, or both.”

Limitations of the metaanalysis
• Sniff position:
• achieved in nonobese patients by raising the occiput 8 to 10 cm with a pillow
or head rest, obese patients require much greater elevation of their head,
neck, and shoulders to produce the same alignment of axes for intubation.
• It has been demonstrated that elevating the upper body and head of
morbidly obese patients to align their sternum and ear in a horizontal line
(head-elevated laryngoscopy position) results in significant improvement in
laryngoscopic view.
– Collins JS, Lemmens HJ, Brodsky JB, Brock-Utne JG, Levitan RM. Laryngoscopy and morbid
obesity: A comparison of the “sniff” and ramped positions. Obes Surg 2004;14:1171–5.
• In two of Shiga et al.’s four references, head position was described only
as sniffing and may therefore have been suboptimal. Suboptimal
positioning would result in a higher incidence of grade 3 and 4 Cormack-
Lehane laryngoscopy views, making direct laryngoscopy and hence
tracheal intubation more challenging. Until a standard intubating
position for obese patients is adopted for research purposes, comparing
studies using different positions will continue to confound the issue.

Methodological limitations of the studies
• noncomparative studies (4,19)
• small numbers of patients (7,20)
– study showing that intubation was more difficult in obese than in nonobese women
during delivery, the statistical analysis included only 17 and 8 patients in
these 2 groups, respectively (20)
– Wilson et al. (7), who identified obesity as a risk factor for difficult
intubation, were able to include only two obese patients and one lean
patient with intubation difficulties.
• Failure to distinguish between difficult intubation and difficult laryngoscopy.
The two do not necessarily go together, however. For instance, in our study,
intubation was more difficult in the obese patients,whereas the incidence of
difficult laryngoscopy (i.e., Cormack class III or IV) was similar in obese and
lean patients. This is not surprising, because factors complicating laryngoscopy
do not reflect the full spectrum of complex events that can make intubation
difficult or easy.
• the negative previous studies, which suggested that obesity and weight were
not risk factors for difficult intubation, also failed to distinguish between
difficult intubation and difficult laryngoscopy (1,6,8,9). In addition, some of
these studies were performed with a small number of patients (9), without

Classification of papers on intubation
in obese patients
author patients BMI surgery Position
for intub
anesthes
ia
Cormack Intub
diff

• the magnitude of obesity does not
influence laryngoscopy difficulty
• Prediction of difficult laryngoscopy in obese patients by ultrasound quantification
of anterior neck soft tissue. Anaesthesia 2003; 58:1111–4
• Juvin P, Lavaut E, Dupont H, Lefevre P, Demetriou M, Dumoulin JL, Desmonts JM:
Difficult tracheal intubation is more common in obese than in lean patients.
Anesth Analg 2003; 97:595–600
• Brodsky JB, Lemmens HJ, Brock-Utne JG, Vierra M, Saidman LJ: Morbid obesity and
tracheal intubation. Anesth Analg 2002; 94:732–6
• Voyagis GS, Kyriakis KP, Dimitriou V, Vrettou I: Value of oropharyngeal Mallampati
classification in predicting difficult laryngoscopy among obese patients.Eur J
Anaesthesiol 1998; 15:330–4

need for a clinically relevant definition
of difficult intubation
•
IDS score
•…vedi oltre)

Conclusions:
• Only superobese may be difficult to
intubate?
• Out of hospital ALS:
•
• The Association Between Obesity and Difficult Prehospital Tracheal Intubation.Holmberg TJ,
Bowman SM, Warner KJ, Vavilala MS, Bulger EM, Copass MK, Sharar SR. Asthma. 2011 Apr;48(3):217-
23. Epub 2011 Feb 21.
• University of Washington, Seattle, Washington;
• In comparison with the lean patient subgroup (BMI <30 kg/m(2)), patients with class III
obesity (BMI >40 kg/m(2)) had a significant association with difficult TI (odds ratio 3.68;
confidence interval [CI] 1.27-10.59), whereas those with class I/II obesity (BMI ≥30 kg/m(2)
and <40 kg/m(2)) did not
• increase in BMI was associated with a 7% increased likelihood of AFI. Men were
approximately 4 times likelier than women to have an AFI. Compared with patients with a
Mallampati Class I or II airway, those with Mallampati Classes III or IV were about 26 times
as likelier to have an AFI.

MALLAMPATI COME CRITERIO
PREDITTIVO,MA A COLLO ESTESO
+DIABETE………………….

Voyagis, G. S.; Kyriakis, K. P.; Dimitriou, V.; Vrettou, I.Value of oropharyngeal Mallampati
classification in predicting difficult laryngoscopy among obese patients.
European Journal of Anaesthesiology 1998,15: 330-334
• 99 obese patients
• Mallampati poor predictor

Intubation difficulties
:
0
5
10
15
20
25
diff.intubation
nonobese
obese
20.2%
7.6%

posterior pharynx visible
OroPharyngeal classification
not visible
nonobese
obese
5
10
15
Protrusione forzata della
lingua migliora la
predittività

Conclusions:
• Whenever obesity is accompanied by an
inability to see the posterior pharyngeal wall,
an elective awake intubation should be
considered.

The extended Mallampati score and a diagnosis of diabetes mellitus
are predictors of difficult laryngoscopy in the morbidly obese.Mashour GA,
Kheterpal S, Vanaharam V, Shanks A, Wang LY, Sandberg WS, Tremper KK. Anesth
Analg. 2008 Dec;107(6):1919-23
• Previous studies have demonstrated that the predictive value of the MMP is improved when the
patient's craniocervical junction is extended rather than neutral (Extended
Mallampati Score, EMS). In the present study, we compared the predictive value of the MMP and EMS in the morbidly obese.
• METHODS:
• We performed a prospective study of adult patients with a Body Mass Index (BMI) > or = 40 over a 12-mo period comparing the MMP and EMS. The
performance of the MMP, EMS, and other commonly used tests was compared for the ability to predict difficult laryngoscopy, defined as a Cormack-
Lehane grade of 3 or 4. Positioning and direct laryngoscopic techniques were not standardized. The incidence of difficult laryngoscopy and difficult
intubation was compared in patients with BMI > or = or < 40.
• RESULTS:
• Three-hundred-forty-six patients with a BMI > or = 40 were evaluated with both the MMP and EMS and received direct laryngoscopy. On average,
craniocervical extension decreased the MMP class (P < 0.0001). Compared to the MMP, the EMS improved specificity and predictive value while
maintaining sensitivity. Compared to the MMP and other tests, an EMS class of 3 or 4 and a diagnosis of diabetes mellitus were the only statistically
significant predictors of difficult laryngoscopy in the morbidly obese. There was no difference in the incidence of difficult laryngoscopy or intubation in
the morbidly obese compared to patients with a BMI < 40.
• CONCLUSIONS:
• The EMS was superior to the MMP in the prediction of
difficult laryngoscopy in the morbidly obese population.
• A diagnosis of diabetes mellitus also warrants further
investigation as a predictor of difficult laryngoscopy in this
population.
• Finally, this study supports previous findings that morbid
obesity is not itself a predictor of difficult laryngoscopy or
intubation

The extended Mallampati score and a diagnosis of diabetes mellitus are
predictors of difficult laryngoscopy in the morbidly obese. Anesth Analg. 2008
Dec;107(6):1919-23
Mashour GA, Kheterpal S, Vanaharam V, Shanks A, Wang LY, Sandberg WS, Tremper KK
1)estensione forzata del collo >
posizione neutra nella
predittività della laringoscopia
difficile
2) il diabete aumenta il rischio di
laringoscopia difficile

Dallo studio di Mashour:suggerimenti per una lista
preop.di valutazione delle vie aeree
• Cervical spine (limited extension, limited flexion, known unstable, possible unstable)
• Neck anatomy (limited laryngeal mobility, mass, radiation changes, thick/obese, thyroid cartilage not visible,tracheal
deviation)
• Thyroid cartilage to mentum distance (6 cm, 6 cm)
• Mouth opening interincisor or intergingival distance (3 cm, 3 cm)
• Mandibular protrusion test (normal: lower incisors can be protruded anterior to upper incisors, limited: lower incisors
can be advanced to only meet upper incisors,severely limited: lower incisors cannot be advanced to meet upper
incisors)
• Mallampati classification (I, II, III, or IV) as modified by Samsoon and Young. Performed with patient sitting with head
in neutral or extended position, mouth maximally open, tongue maximally protruded, without phonation
• Full beard (yes, no, moustache, or goatee)
• Dentition (normal, dentures upper partial, dentures upper complete, dentures lower partial, dentures lower
complete, edentulous, teeth missing/loose/broken)
• History of cough (chronic, recent, productive, nonproductive)
• History of rhinorrhea
• History of chronic obstructive pulmonary disease (chronic bronchitis or emphysema requiring treatment with inhaled
or systemic steroids or bronchodilators)
• History of asthma (requiring treatment with inhaled or systemic steroids or bronchodilators)
• History of snoring occurring nightly
• History of obstructive sleep apnea (requiring continuous positive airway pressure, bilevel positive airway pressure, or
surgery)
• Airway evaluations are nonquantitative and based on physical examination, unless otherwise noted.

.
Neligan PJ, Porter S, Max B, Malhotra G, Greenblatt EP, Ochroch EA.
Obstructive sleep apnea is not a risk factor for difficult intubation in morbidly
obese patients. Anesth Analg. 2009 Oct;109(4):1182-6
• Department of Anaesthesia and Critical Care, Hospital of University of Pennsylvania, Philadelphia, PA, USA.
• 180 pts for bariatric surgery, mean BMI was 49.4 kg/m(2
• predictive factors tested: OSA and its severity, as determined by apnea-hypopnea index (AHI), gender,
NC, and body mass index (BMI).
• standardized anesthetic that included positioning in the "ramped position" for direct laryngoscopy.
• All the patients' tracheas were intubated successfully without the aid of rescue airways by
anesthesiology residents.
• 6 patients required 3 or + intubation attempts, a difficult intubation rate of 3.3%.
• 8.3% incidence of difficult laryngoscopy, defined as a Cormack and Lehane Grade 3 or 4 view.
• no relationship between NC and difficult intubation (odds ratio 1.02, 95% confidence interval 0.93-
1.1), between the diagnosis of OSA and difficult intubation (P = 0.09), or between BMI and difficult
intubation (odds ratio 0.99, 95% confidence interval 0.92-1.06, P = 0.8). There was no relationship
between number of intubation attempts and BMI (P = 0.8), AHI (P = 0.82), or NC (P = 0.3).
• Mallampati Grade III or more predicted difficult intubation (P = 0.02), as did male gender (P = 0.02).
Finally, there was no relationship between Cormack and Lehane grade and BMI (P = 0.88), AHI (P =
0.93), or OSA (P = 0.6). I
• ncreasing NC was associated with difficult laryngoscopy but not difficult intubation (P = 0.02).
• CONCLUSIONS:
• In MO patients undergoing bariatric surgery in the "ramped position," there was no
relationship between the presence and severity of OSA, BMI, or NC and difficulty of
intubation or laryngoscopy grade. Only a Mallampati score of 3 or 4 or male gender
predicted difficult intubation

Criticism(my) of Neligan et al
• “ramped” position by stacking blankets behind the patient’s back,
resulting in elevation of the head, upper body, and shoulders
significantly above the chest.: the external auditory meatus was
horizontal with the sternal notch, and this was checked by a trained
observer in each patient.
• standardized induction of anesthesia with propofol (1–2 mg/kg) and
fentanyl (1–2 g/kg),and neuromuscular blockade achieved with
vecuronium (0.1 mg/kg) or succinylcholine (1 mg/kg).
• The first three laryngoscopic attempts were to be performed by an
anesthesiology resident. Subsequent attempts were to be
performed by an attending anesthesiologist, in keeping with clinical
practice at our institution.
• PreO2????

Conclusion from Neligan et al.
• OSA is not predictive of difficult
intubation in obese
• (positioning in the “ramped position” for direct laryngoscopy)
• Only a Mallampati score of 3 or 4
or male gender predicted
difficult intubation
• vedi la loro discussione

ALLORA VEDIAMO UN POCO LA
LETTERATURA;COMINCIAMO A
DEFINIRE LA INTUBAZIONE DIFFICILE
……………….

Tra l’altro,le vie aree degli obesi sono
più reattive….
• Allergy Asthma Proc. 2011 Jan;32(1):68-73.
• Association between subcutaneous abdominal fat and airway
hyperresponsiveness.
• Kim KM, Kim SS, Kwon JW, Jung JW, Kim TW, Lee SH, Min KU, Kim YY, Cho
SH.
• Department of Internal Medicine, Dankook University College of Medicine, Cheonan-si, Chungcheongnam-do,
Korea.
• Abstract
• Epidemiological studies have shown that obesity is significantly associated with airway hyperresponsiveness
(AHR). The aim of this study was to determine the effect of abdominal fat distribution on the prevalence of AHR.
This study was conducted on subjects who visited the Seoul National University Hospital Gangnam Center from
October 2003 to January 2009. Medical records of 3205 subjects who had both a methacholine bronchial
provocation test and an abdominal CT scan were retrospectively reviewed. One hundred sixty-one subjects with
AHR and their 161 controls were selected for the analysis. Total, subcutaneous, and visceral abdominal fat were
objectively measured by an abdominal CT scan. Both body mass index (BMI) and waist circumference were
significantly associated with AHR after adjustment for smoking (BMI: OR, 1.20; 95% confidence interval [CI], 1.07-
1.35; waist circumference: OR, 1.07; 95% CI, 1.02-1.11). Total and subcutaneous abdominal fat increased the risk
of AHR with an OR of 1.47 (95% CI, 1.08-2.02) in the case of total abdominal fat, and an OR of 1.99 (95% CI, 1.19-
3.31) in the case of subcutaneous abdominal fat. However, visceral abdominal fat was not associated with AHR.
The association between subcutaneous abdominal fat and AHR was consistent, especially in men. Subcutaneous
abdominal fat was significantly associated with AHR, but visceral abdominal fat was not. These results suggest a
possible role for subcutaneous fat on the later development of asthma.

Intubation difficulty assessment(score)
• IDS developed by Adnet et al. (10)
– Adnet F, Borron SW, Racine SX, et al. The intubation difficultyscale (IDS): proposal and evaluation of a new score
characterizing the complexity of endotracheal intubation. Anesthesiology 1997;87:1290–7.
on the basis of 7 variables associated with difficult intubation.

IDS score
• is the sum of N1 through N7.
• A score of 0 indicated intubation under ideal
conditions, performed on the first attempt by the
first operator, who used a single technique and
applied minimal force to insert the tube through
a fully visualized glottis.
• An IDS score from 1 to 5 indicated slight difficulty
• an IDS score 5 or +indicated moderate to major
difficulty.

Difficult Tracheal Intubation Is More Common in Obese Than in
Lean Patients Juvin P., Lavaut E, Dupont H, Lefevre P, Demetriou M,
Dumoulin JL, Desmonts JM.Anesth Analg 2003;97:595–600)
• 140 obese
• No intubation impossible
• The incidence of difficult intubation was more
frequent in the obese than in the lean patients

Difficult Tracheal Intubation Is More Common in Obese
Than in Lean Patients Juvin P., Lavaut E, Dupont H, Lefevre P, Demetriou M,
0
10
20
30
40
50
60
70
lean obese
IDS 0
IDS>1 <5
IDS=>5
overall difficulty
semirecumbent position (30°) with the head in the sniffing
position
PreO2
propofol (2–2.5 mg/kg) + succi (1 mg/kg)
Cricoid pressure( Sellick)
Macintosh No. 3 laryngoscope blade always

Difficult Tracheal Intubation Is More Common in Obese Than in
Lean Patients Juvin P., Lavaut E, Dupont H, Lefevre P, Demetriou
M, Dumoulin JL, Desmonts JM.Anesth Analg 2003;97:595–600)
• Mallampati score of III or IV was an independent
risk factor for difficult intubation in obese
patients, whereas obesity (i.e., BMI) was not.
• The sensitivity of the Mallampati score was 100%
and 85%, its specificity was 74% and 62%, its
positive predictive value was 8% and 29%, and its
negative predictive value was 100% and 96% in
lean and obese patients, respectively.

Difficult Tracheal Intubation Is More Common in Obese Than in Lean
Patients Juvin P., Lavaut E, Dupont H, Lefevre P, Demetriou M,

Brodsky JB, Lemmens HJ, Brock-Utne JG, et al. Morbid obesity and
tracheal intubation. Anesth Analg. 2002;94(3):732–736
• 78 women and 22 men
• aged 44 yr (interquartile range, 36 –51 yr) were studied
• Weight was 137 kg (interquartile range, 124 –156 kg)
• height was 168 cm (interquartile range, 160 –173 cm)
• BMI was 47.5 kg/m2 (interquartile range, 43.9 –56.6 kg/m2).
• Forty-four patients had a history suggestive or diagnostic of OSA; 56 had no evidence
of OSA.
• The median neck circumference was 46.0 cm (interquartile range, 42.0–49.0 cm),
• the sternomental distance was 14.0 cm (interquartile range, 12.0–17.0 cm),
• thyromental distance was 9.5 cm (interquartile range, 8.0–11.0 cm).
• In 30, 37, 32, and 1 patients, Mallampati scores were 1, 2, 3, and 4, respectively.
• during initial laryngoscopy, the view of the larynx was Grade 1 in 75 patients, Grade 2
in 16 patients, and Grade 3 in 9 patients. No patient had a Grade 4 view.
• In 92, 5,and 2 patients, the trachea was intubated on the first, second, and third
attempts, respectively.
• A failed intubation with direct laryngoscopy occurred in one patient.
• In 97 patients the tracheas were intubated by the anesthesia resident; 3 patients
required intubation by

Brodsky JB, Lemmens HJ, Brock-Utne JG, et al. Morbid obesity and
tracheal intubation. Anesth Analg. 2002;94(3):732–736
• The logistic regression model predicts that the
odds of a problematic intubation in a
particular patient with a neck circumference
1cm larger than that of another patient are
1.13 (95% CI, 1.02 to 1.25) times the odds of
the patient with a 1 cm smaller neck
circumference. Therefore a 40 cm neck
circumference carries a 5% probability of
problematic intubation and at 60 cm the
probability rises to 35%.

Brodsky JB, Lemmens HJ, Brock-Utne JG, et al. Morbid
obesity and tracheal intubation. Anesth Analg.
2002;94(3):732–736

Brodsky JB, Lemmens HJ, Brock-Utne JG, et al. Morbid
obesity and tracheal intubation. Anesth Analg.
2002;94(3):732–736
A larger neck circumference was associated
with:
• men (P 0.001),
• a higher Mallampati score (P 0.0029),
• Grade 3 views during laryngoscopy (P
0.0375)
• OSA (P 0.0372)

Conclusions
• neither absolute obesity nor increasing BMI was
associated with problematic intubation in morbidly
obese patients.
• Problematic intubation was associated with increasing
neck circumference and a Mallampati score = >3.
• A poor view during direct laryngoscopy was not a factor
in successful intubation because in all but one patient
the trachea was intubated by direct laryngoscopy
• The experience and ability of the laryngoscopist are
probably the most important determinants for
establishing an airway in the morbidly obese patient.
• Because anesthesia residents successfully intubated the
trachea in almost all our patients, the success rate would
be expected to be even higher when fully trained
anesthesiologists manage the airway.

Neck circumference
• Articoli che confermano l’importanza della circonferenza del collo:
– The importance of increased neck circumference to intubation
difficulties in obese patients Gonzalez H, Minville V, Delanoue K, Mazerolles M, Concina D, Fourcade O. The
importance of increased neck circumference to intubation difficulties in obese patients. Anesth Analg. 2008 Apr;106(4):1132-6,
– Prediction of difficult laryngoscopy in obese patients by ultrasound
quantification of anterior neck soft tissueT. Ezri, G. Gewürtz, D.I. Sessler, B. Medalion, P.
Szmuk, C. Hagberg, and S.Susmallian.Anaesthesia. 2003 November ; 58(11): 1111–1114.
• Anche nei bambini!!!(ma non intub difficulties)
– high NC positively correlated with age and other anthropometric
parameters
– Children with high NC were more likely to be loud snorers and have a
history of bronchial asthma, hypertension, and type 2 diabetes.
– Composite adverse airway events were more frequent in
children with a large NC
– Pediatrics. 2011 Apr 4. [Epub ahead of print],Association of Neck
Circumference With Perioperative Adverse Respiratory Events in
Children.Nafiu OO, Burke CC, Gupta R, Christensen R, Reynolds PI,
Malviya S.
•

Pediatric obesity : a chi è interessato
raccomando …
• Anesthetizing the obese child.
• Mortensen A, Lenz K, Abildstrøm H, Lauritsen TL. Chest. 2011
Mar 17. [Epub ahead of print]
• Department of Anesthesiology, Juliane Marie Centre, Copenhagen University Hospital,
Rigshospitalet, Copenhagen, Denmark Department of Anesthesia, Center of Head and
Orthopedics, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.
• Abstract
• The prevalence of childhood obesity is increasing. The focus of this review is the special anesthetic considerations regarding
the perioperative management of obese children. With obesity the risk of comorbidity such as asthma, obstructive sleep
apnea, hypertension, and diabetes increases. The obese child has an increased risk of perioperative complications especially
related to airway management and ventilation. There is a significantly increased risk of difficult mask ventilation and
perioperative desaturation. Furthermore, obesity has an impact on the pharmacokinetics of most anesthetic drugs. This has
important implications on how to estimate the optimal drug dose. This article offers a review of the literature on definition,
prevalence and the pathophysiology of childhood obesity and provides suggestions on preanesthetic evaluation, airway
management and dosage of the anesthetic drugs in these patients. The authors highlight the need of supplemental studies
on various areas of the subject
• More adverse periop events in obese children!!!
– Br J Anaesth. 2011 Mar;106(3):359-63. Epub 2010 Dec 10..Incidence of perioperative adverse events
in obese children undergoing elective general surgery.El-Metainy S, Ghoneim T, Aridae E, Abdel
Wahab M.

T. Ezri, G. Gewürtz, D.I. Sessler, B. Medalion, P. Szmuk, C.
Hagberg, S.Susmallian
Anaesthesia. 2003 November ; 58(11): 1111–1114.
• Prediction of difficult laryngoscopy in obese
patients by ultrasound quantification of anterior
neck soft tissue
• The distance from the skin to the anterior aspect
of the trachea was measured at three levels:
• vocal cords (zone 1 – Fig. 1)
• thyroid isthmus (zone 2)
• suprasternal notch (zone 3)
•

T. Ezri, G. Gewürtz, D.I. Sessler, B. Medalion, P. Szmuk, C. Hagberg,
and S.Susmallian. Prediction of difficult laryngoscopy in obese
patients by ultrasound quantification of anterior neck soft
tissue.Anaesthesia. 2003 November ; 58(11): 1111–1114.
• There were 9 cases (18%) of difficult laryngoscopy.
• 7/9 patients with difficult laryngoscopy had a history of obstructive sleep
apnoea whereas only 2/41 patients with easy laryngoscopy did (P < 0.001).
Patients with difficult laryngoscopy had a larger neck circumference [50
(3.8) cm] than patients with easy laryngoscopy [43.5 (2.2) cm]; P < 0.001).
• The difficult laryngoscopy patients also had much more soft tissue in zone
1 [(28 (2.7) mm] than did patients with easy laryngoscopy [17.5 (1.8) mm,
P < 0.001 - Fig. 2], as well as in zone 3 [33(4.3) vs 27.4 (6.6), P < 0.013].
• Zone 1 soft tissue appears to be the best predictor of a difficult
laryngoscopy. The range of zone 1 soft tissue for those with difficult
laryngoscopy (24–32 mm) was mutually exclusive from those patients with
an easy laryngoscopy (15–22 mm); hence, the zone 1 soft tissue values
completely separated the difficult and easy laryngoscopies (Fig. 2). In
contrast, the range for neck circumference had some overlap for those
with difficult (45–57 cm) and easy (38–48 cm) laryngoscopy.

. Ezri, G. Gewürtz, D.I. Sessler, B. Medalion, P. Szmuk, C. Hagberg, and S.Susmallian. Prediction
of difficult laryngoscopy in obese patients by ultrasound quantification of anterior neck soft
tissue.Anaesthesia. 2003 November ; 58(11): 1111–1114.

Conclusioni di Ezri e coll:
• Difficult laringoscopy associated with:
• history of obstructive sleep apnoea
• larger neck circumference [50 (3.8) cm] than patients with easy
laryngoscopy [43.5 (2.2) cm).
• much more soft tissue in zone 1 [(28 (2.7) mm] than did patients with easy
laryngoscopy [17.5 (1.8) mm, as well as in zone 3 [33(4.3) vs 27.4 (6.6)
• Zone 1 soft tissue appears to be the best predictor of a difficult
laryngoscopy.
• The range of zone 1 soft tissue for those with difficult laryngoscopy (24–32
mm) was mutually exclusive from those patients with an easy laryngoscopy
(15–22 mm); hence, the zone 1 soft tissue values
completely separated the difficult and easy
laryngoscopies (Fig. 2).
• In contrast, the range for neck circumference had some overlap for those
with difficult (45–57 cm) and easy (38–48 cm) laryngoscopy.

Gonzalez H, Minville V, Delanoue K, Mazerolles M, Concina D, Fourcade
O. The importance of increased neck circumference to intubation
difficulties in obese patients. Anesth Analg. 2008 Apr;106(4):1132-6,
• Department of Anesthesiology and Intensive Care, University Hospital of Toulouse, Toulouse, France.
• Abstract
• BACKGROUND:
• Using the intubation difficulty scale (IDS), we sought to confirm that obese patients are more difficult to intubate
than lean patients. We assessed classical bedside tests and included neck circumference.
• METHODS:
• We prospectively compared the incidence of difficult tracheal intubation in 70 obese [body mass index (BMI) > or
= 30 kg/m(2)] and 61 lean patients (BMI < 30 kg/m(2)). The IDS scores, categorized as difficult intubation (IDS > 5)
or not (IDS < or = 5), and the patient data, were compared between lean and obese patients. Preoperative
measurements [BMI, neck circumference (at the level of the thyroid cartilage), width of mouth opening,
sternomental distance, and thyromental distance], medical history of obstructive sleep apnea syndrome, and
several scores (Mallampati, Wilson, El Ganzouri) were recorded. The view during direct laryngoscopy was graded,
and the IDS was recorded. We then compared patients with IDS < or = 5 and > 5, concerning each item.
• RESULTS:
• The results indicate that difficult tracheal intubation is more frequent in obese than in lean patients (14.3% vs 3%;
P = 0.03). In the patients with IDS > 5, thyromental distance, BMI, large neck circumference, and higher
Mallampati score were the only predictors of potential intubation problems.
• CONCLUSION:
• We found that problematic intubation was associated with thyromental distance, increasing neck circumference,
BMI, and a Mallampati score of > or = 3. Neck circumference should be assessed preoperatively to predict difficult
intubation

Gonzalez H, Minville V, Delanoue K, Mazerolles M, Concina D, Fourcade O. The
importance of increased neck circumference to intubation difficulties in obese patients.
Anesth Analg. 2008 Apr;106(4):1132-6,

Gonzalez H, Minville V, Delanoue K, Mazerolles M, Concina D, Fourcade
O. The importance of increased neck circumference to intubation
difficulties in obese patients. Anesth Analg. 2008 Apr;106(4):1132-6,

Gonzalez H, Minville V, Delanoue K, Mazerolles M, Concina D, Fourcade O. The
importance of increased neck circumference to intubation difficulties in obese
patients. Anesth Analg. 2008 Apr;106(4):1132-6,
Wilson score:simple summation of :
The distance from the thyroid notch to the mentum (thyromental distance), the distance
from the upper border of the manubrium sterni to the mentum (sternomental distance),

Gonzalez H, Minville V, Delanoue K, Mazerolles M, Concina D, Fourcade O.
The importance of increased neck circumference to intubation difficulties
in obese patients. Anesth Analg. 2008 Apr;106(4):1132-6,
• Among the potential predictors we evaluated,
thyromental distance, BMI, neck circumference,
and a Mallampati score >3 were the only useful
bedside test predictors of difficult intubation.
• Our results thus confirm the work of Brodsky et al.5 who showed that neck
circumference at the thyroid cartilage is a valuable predictor of difficult aryngoscopy in
obese patients. Interestingly, all other putative predictors were similar in the two
populations. Moreover, neck circumference also seems to be a predictive test in lean
patients. Circumference does not indicate the amount of soft tissue at various
topographic regions within the neck. Distribution of fat in specific neck areas, especially
the anterior neck, may provide a better indication of difficult intubation than neck
circumference. By using magnetic resonance imaging measurements in obese patients
with and without OSA syndrome, Horner et al. demonstrated that more fat was present
in areas surrounding the collapsible segments of the pharynx in patients with OSA
syndrome.24 This may explain why some obese patients are easy to intubate/ventilate,
while others are not. Furthermore, difficult intubation had been significantly associated

True pos,neg pos,false pos,false neg
• True positive a difficult intubation that had been predicted to be difficult.
• False positive an easy intubation that had been predicted to be difficult.
• True negative an easy intubation that had been predicted to be easy.
• False negative a difficult intubation that had been predicted to be easy.
• Sensitivity the percentage of correctly predicted difficult intubations as a proportion of all
intubations that were truly difficult, i.e.:True positives/(true positives +false negatives)
• Specificity the percentage of correctly predicted easy intubations as a proportion of all
intubations that were truly easy, i.e.: True negatives/(true negatives +false positives)
• Positive predictive value the percentage of correctly predicted difficult intubations as a
proportion of all predicted difficult intubations, i.e.: True positives/(true positives f+alse
positives)
• Negative predictive value the percentage of correctly predicted easy intubations as a
roportion of all predicted easy intubations, i.e.: True negatives/(true negatives +false
negatives)

Does neck circumference predict difficult laryngoscopy in
morbidly obese patients?
H. Abrahams, C. Bygrave, C. Doyle, A. Kendall, M. Margarson
• 19AP2-5
• Department of Anaesthesiology and Intensive Care, St Richard’s Hospital, Chichester, United Kingdom
• Background and Goal of Study: Morbidly obese patients are reported to be more difficult to intubate than the
general population. The single greatest predictor of difficult intubation is suggested to be a neck circumference
of ≥50cm, this is based on a study of 100 patients1. For the past three years we have entered neck
circumference data onto our anaesthetic database and have analysed it to confirm or refute this assertion.
• Materials and Methods: Between January 2008 and December 2009, 836 Morbidly Obese patients (149 with
BMI >60 kg/m2) underwent Roux-en-Y Gastric Bypass or Gastric Banding at our Bariatric Unit. All patients were
seen pre-operatively in a multi-disciplinary outpatient clinic where demographic data including neck
measurement and Mallampati score were recorded. On the day of surgery the grade of laryngoscopy, according
to the classification of Cormack and Lehane, was recorded. Notes were reviewed and data entered onto the
database. Analysis of Variance between the patients grouped by grade of laryngoscopy was performed using the
Kruskal-Wallis test.
• Results and Discussion: Full data was available on 503 patients (126 male, 25%) with a median age of 44 years
(range 17-73). The median BMI was 51kg/m2 (range 32-100) and the median weight was 143 kg (range 89-289
kg). ANOVA demonstrated a highly significant difference between the median values. (p<0.0001) The overall
incidence of Cormack & Lehane Grade 3 or 4 Laryngoscopy was 6.6%. In the 91 patients with a neck
circumference ≥50cm the incidence was 21%.
• Cormack + Lehane Grade 1 2a 2b 3 or 4Median Neck Circumference (cm) 43 45 46 50.5Interquartile range 41 - 47
42 - 49 43 - 50.3 43.8 - 58
• Conclusion(s): There is a clear and stepwise correlation between difficult
laryngoscopy and neck circumference in these patients. The overall incidence of
difficult laryngoscopy is not high, but a neck circumference ≥50cm does appear to
be a strong predictor.

Does neck circumference predict difficult laryngoscopy in
morbidly obese patients?
H. Abrahams, C. Bygrave, C. Doyle, A. Kendall, M. Margarson
There is a clear and stepwise correlation between difficult laryngoscopy
and neck circumference in these patients. The overall incidence of
difficult laryngoscopy is not high, but a neck circumference ≥50cm
does appear to be a strong predictor.

Ann Otol Rhinol Laryngol. 2007 Nov;116(11):799-804.
Prediction of difficult laryngoscopy: does obesity play a role?
Hekiert AM, Mick R, Mirza N
• .
• Source
• Department of Otorhinolaryngology-Head and Neck Surgery, University of Pennsylvania
Medical Center, 3400 Spruce St, 5th Floor Ravdin Bldg, Philadelphia, PA 19104, USA.
• Abstract
• OBJECTIVES:
• This study was intended to 1) identify preoperative predictors of difficult laryngoscopy and 2) determine the role of
obesity in difficulty of obtaining adequate laryngeal exposure.
• METHODS:
• A prospective study was undertaken of 63 patients who were undergoing elective direct laryngoscopy. Thirty-six
patients met the obesity criteria (body mass index of at least 30 kg/m2). Measurements of height, weight, and neck
circumference and Mallampati and Cormack-Lehane scores were obtained. The ease of laryngeal exposure was
recorded by the attending surgeon on a visual analog scale (VAS; 1 to 10). Difficult laryngeal exposure (DLE) was
defined as a VAS score of at least 3. The candidate morphological predictors were investigated.
• RESULTS:
• Obesity and Mallampati score were found to be predictors of DLE (p < .001). The VAS score was
positively correlated with body mass index (p = .007), weight (p = .05), Mallampati score (p < .001), and Cormack-
Lehane score (p < .001). Among obese patients, the VAS score was correlated with the Cormack-Lehane score (p =
.01), whereas in nonobese patients the VAS score showed a significant association with both the Mallampati (p =
.02) and Cormack-Lehane (p = .01) scores.
• CONCLUSIONS:
• Obese patients and those with a Mallampati score of at least 2 posed a significantly higher risk of DLE. Preoperative
identification of a potentially difficult airway may aid surgical planning and allow more effective communication
with a collaborating anesthesiologist

Hekiert, A., Mick, R., & Mirza, N. (2007). Prediction of difficult laryngoscopy: does
obesity play a role? Annals of otology, rhinology & laryngology, 116(11), 799-804.
• Unfortunately there was data missing from 30 patients in this study. The
missing data was the Cormack Lehane grades. Given this gross mishap in their
data collection this author has excluded any results pertaining to the
laryngoscopic view as reliability and validity of those results is questionable…
• Una volta che ci potevano dare una mano……………..

Obes Surg. 2010 Oct;20(10):1436-41.
An evaluation of the rapid airway management positioner in obese patients
undergoing gastric bypass or laparoscopic gastric banding surgery.
Cattano D, Melnikov V, Khalil Y, Sridhar S, Hagberg CA.
• Source
• Department of Anesthesiology, The University of Texas Medical School at Houston, 6431 Fannin, MSB 5.020, Houston, TX
77030, USA.
• 51 obese BMI>35 for bariatric surgery
• Ease of Ventilation and laryngoscopy was performed in the neutral and head-
elevated laryngoscopy position (HELP). (Rapid Airway Management Positioner
(RAMP, Airpal Inc., Center Valley, PA)
• Direct laryngoscopy was performed noting the glottic view according to the
Cormack-Lehane classification (Samsoon and Young, Anesthesiology 42:487,
1987). Mask ventilation was then recommenced.
• Once proper HELP position was achieved, a second laryngoscopy was
performed followed by endotracheal intubation.
• The inflated ramped position provided greater ease of ventilation as compared
to the neutral position (p = 0.0003).
• There was also a significant improvement in the glottic view in the ramped
position (p = 0.04)
• The RAMP effectively positions morbidly obese patients in the HELP position.
Ease of ventilation and laryngoscopic view were both improved with its use in
this patient population

J Clin Anesth. 2009 Jun;21(4):264-7. Epub 2009 Jun 6.
Predicting difficult airways using the intubation difficulty scale: a study
comparing obese and non-obese patients.
Lavi R, Segal D, Ziser A.
• To compare intubation difficulty in obese and non-obese patients by intubation difficulty scale (IDS),
intubation duration measurement, and oxygen saturation (SaO(2)) levels.
• 204 ASA physical status I, II, and III adult patients who underwent elective surgery with endotracheal
intubation.
• Preoperative airway parameters, intubation duration, IDS scores, and lowest SaO(2) during intubation were
recorded.
• MAIN RESULTS:
• IDS scores were higher in the obese group than the non-obese (2.29 +/- 0.45 and 1.26 +/- 0.2, respectively, P
= 0.03). Intubation duration was 45.1 +/- 6 sec for obese versus 36.8 +/- 2.6 sec for the non-obese group (P =
0.20). The lowest SaO(2) recorded was 97%, with no difference noted between groups. Mallampati class
>or=3 was found to positively predict intubation difficulty scores greater than 5.
• CONCLUSIONS:
• Difficult intubation was more prevalent among obese than non-obese patients, but intubation duration and
lowest SaO(2) levels during intubation were not. Moreover,
• the modified Mallampati test was found to be a moderately
good (60%) predictor of difficult intubation among obese
patients
• sniffing position. All laryngoscopies were performed using a size 3
Macintosh blade, and the trachea was intubated with a cuffed
endotracheal tube. An intubation stylet was not used routinely

The IDS N 5 group had the highest BMI, although some overlap existed between
the groups. Lavi R, Segal D, Ziser A. Predicting difficult airways using the intubation difficulty scale: a
study comparing obese and non-obese patients. J Clin Anesth. 2009 Jun;21(4):264-7.

Intubation difficulty scale (IDS) scores and intubation
duration among obese and non-obese patients. The IDS score was
significantly higher in obese patients, but intubation duration did
not differ significantly between the groups

Rao SL, Kunselman AR Schule HG, DesHarnais S.Laryngoscopy and Tracheal
Intubation in the Head-Elevated Position in Obese Patients: A Randomized,
Controlled, Equivalence Trial..Anesth Analg 2008;107:1912–8
• BACKGROUND: The proper positioning of patients before direct laryngoscopy is a key step that facilitates tracheal intubation. In
obese patients, the 25 degree back-up or head-elevated laryngoscopic position, which is better than the supine position for
tracheal intubation, is usually achieved by placing blankets or other devices under the patient’s head and shoulders. This position
can also be achieved by reconfiguring the normally flat operating room (OR) table by flexing the table at the trunk-thigh hinge
and raising the back (trunk) portion of the table (OR table ramp). This table-rampmethod can be used without the added
expense of positioning devices, and it reduces the possibility of injury to the patient or providers that can occur during removal
of such devices once tracheal intubation is achieved.
• In this study, we sought to determine if the table-ramp method of patient positioning was equivalent to the
blanket method with regard to the time required for tracheal intubation.
• 85 adults with a Body Mass Index> 30 kg/m2, scheduled for elective surgery,
• prospective randomized equivalence study conducted in a teaching hospital
• randomization scheme used permuted blocks with subjects equally allocated to be positioned using either the
blanket method or the table-ramp method.
• end-point in either case : head-elevated position, where the patient’s external auditory meatus and sternal
notch were in the same horizontal plane
• all patients were positioned by the same anesthesiologist,
• laryngoscopy and tracheal intubation were performed by trainees with various levels of expertise.
• Standard IV induction and tracheal intubation techniques were used. The time from loss of consciousness to
the time after tracheal intubation when end-tidal CO2 was detected was recorded.
• The effectiveness of mask ventilation and quality of laryngeal exposure were also noted.
• RESULTS: The mean time (sd) to tracheal intubation was 175 (66) s in the blanket group, as compared to 163
(71) s in the table-ramp group. Assuming the bounds for equivalence are 55,55 s, our study found a 95%
confidence interval of 36.22,13.52 s using two one-sided tests for equivalence corresponding to a significance
• level of 0.05. There was no difference in the number of attempts at laryngoscopy (P 0.21) and tracheal
intubation (P 0.76) required to secure the airway between the two groups.
• CONCLUSIONS: Before induction of anesthesia, obese patients can be positioned with their head elevated
above their shoulders on the operating table, on a ramp created by placing blankets under their upper body or
by reconfiguring the OR table. For the purpose of direct laryngoscopy and tracheal intubation, these two
methods are equivalent. ()

Outcome variables in the study by Rao et al.

Time required to secure the airway(from LOC to etCO2 detection Rao
SL, Kunselman AR Schule HG, DesHarnais S.Laryngoscopy and Tracheal Intubation in the Head-Elevated Position in
Obese Patients: A Randomized,Controlled, Equivalence Trial..Anesth Analg 2008;107:1912–8)

Conclusions from Rao et al ;the 2 positions RAMP
with blankets or with ORtable are equivalent for
the purpose of tracheal intubation,but……….
• It is easier with the electronic controls of the OR table to recreate a
table ramp during emergence instead of reinserting blankets under
the patient.
• Surgeons prefer not to have blankets under the anesthetized patient
during surgery
• As a larger portion of the patient’s back is in contact with the
operating table surface when blankets are not used to position
patients, the likelihood of injury to the patient’s skin is minimized
when blankets are removed after tracheal intubation. However, injury
to OR personnel may occur when an attempt is made to
• lift or move patients so that the blankets can be removed from under
the patients after tracheal intubation.
• Use of the electronic controls of the OR table to position patients
avoids these problems.

Conclusion about intubation
difficulty(es) with obese patients:
• The evidence is contradictory,but
• Difficult laryngoscopy is not sinonimous
with difficult intubation
• Large neck (and especially fat accumulated
anteriorly at the level of the vocal
cords)and Mallampati 3 & 4 are associated
with difficulties;+diabetes and
superobese(BMI>60);
• Awake FOB intubation!

Conclusions 2
• (Partly I wonder whether this is due to a greater degree of vigilance and better preparation/positioning than for the non-obese patient.)
• BMI per se is not a factor of difficulty
• Sleep apnea is not a factor for difficulty
• Patient must be positioned in the ramped position(or 30 degree anti
trendelemburg+ slight ramped)
• Look always for anatomical factors for difficult
intubation :combination of tests > single test
• Mallampati with forced tongue and neck extension
– Restricted flexion and extension of the neck and atlantooccipital joint – because of numerous
chins and low cervical and upper thoracic fat pads/large breasts.
– Mouth opening can be limited by submental fat.
– Airway may be narrowed by fleshy cheeks, a large tongue and copious pads of palatal,
pharyngeal and supralaryngeal soft tissues.
– A high anterior and infantile laryngeal position may be presentT

Conclusion 3:POGO score
La RAMP position deve sempre essere usata per
facilitare la visione glottica e la intubazione:
Collins JS, Lemmens HJ, Brodsky JB, Brock-Utne JG, Levitan RM. Laryngoscopy and morbid
obesity: a comparison of the "sniff' and "ramped" positions. Obes Surg 2004;14:1–5
Questo è vero anche in pazienti normali!
Lee BJ, Kang JM, Kim DO. Laryngeal exposure during laryngoscopy is better in the 25 degrees back-up
position than in the supine position
. Br J Anaesth 2007;99:581–6

Lee BJ, Kang JM, Kim DO. Laryngeal exposure during laryngoscopy is better in the 25
degrees back-up position than in the supine position
. Br J Anaesth 2007;99:581–6
• Laryngoscopy with a curved blade was performed on 40 anaesthetized patients.
• The patients were randomly assigned to two groups.
• Laryngeal views were captured with a rigid Olympus endoscope. Views were
recorded for each patient in Group A (n¼20) during laryngoscopies performed with
the patient lying first in the supine position and then in the 258 back-up position.
Laryngeal views for patients in Group B (n¼20) were first captured while the
patient was in the 258 back-up position and then while the patient was in the flat
supine position.
• An anaesthetist blinded to the position graded the quality of the images using the
percentage of glottic opening (POGO) score.
• Results. Comparing the two positions, mean (SD) POGO scores increased
significantly from 42.2 (27.4)% in supine position to 66.8
(27.6)% in 25 o back-up position (P,0.0001).
• Conclusions. During laryngoscopy, the laryngeal view, as assessed by POGO scores,
improves significantly in the 258 back-up position when compared with the flat
supine position.

POGO score:percentage of glottic
opening

POGO scores increased significantly from 42.2 (27.4)% in supine position to 66.8 (27.6)% in
25 o back-up position.
Lee BJ, Kang JM, Kim DO. Laryngeal exposure during laryngoscopy is better in the 25 degrees back-up position than in the
supine position
. Br J Anaesth 2007;99:581–6

A 45o direction to lift the handle of the laryngoscope in the supine-horizontal position
decreases to about 20o in the 25o back-up position (Fig. 4).
A change of direction to lift the handle leads to a change of force and torque.
Vertical force against gravity will be decreased and horizontal force increased in the back-up
position. In the back-up position, a laryngoscopist can push the blade of the laryngoscope
forward rather than upward with the same force and get an improved view of the larynx.

• Figure 5 shows that the anterior movement of laryngeal structures caused by
anaesthesia and head extension displaces the LA, defined as a straight line
passing through the centres of the inferior (cricoid cartilage) and superior (base of
epiglottis) orifices vertically without modification of the angle.
• In contrast, the line of vision (LV), defined as a straight line passing through
theinferior extremity of the superior incisors and the posterior extremity of the
superior portion of the cricoid cartilage is slightly affected by this change and thus,
a slight decrease in the angle between LA and LV can be expected.11
• In the 25o back-up position, laryngeal structures move a little more caudally by the
gravity than in the supine position and the angle between LA and LV can be
further decreased. The gravitational force may pull the laryngeal structures
caudally directly and indirectly by pulling whole structure of upper thorax
connected to the laryngeal structures.
• In the paralysed patients, the muscle tone to support the laryngeal structures will
be lessened and the effect of gravity will be even more than that seen in awake
and unparalysed patients. Thus, the change of effects of gravitational force in the
caudal direction cannot be neglected.

Time limits,emergencies,poor positioning could be
factors for difficult intubation in obese patients
• Levitan RM, Everett WW, Ochroch EA.
Limitations of difficult airway prediction in
patients intubated in the emergency
department. Ann Emerg Med 2004;44:307–13
• Levitan RM, Chudnofsky C, Sapre N.
Emergency airway management in a morbidly
obese, noncooperative, rapidly deteriorating
patient. Am J Emerg Med 2006;24:894–6

Prone position??
• For the prone position one should consider awake
intubation. Then the patient can position him or
herself..
• The Lateral Decubitus position is sometimes used as a
substitute for the prone position.
• It should be taken as a positive that few reports are in
the literature of problems placing obese patients in this
position. Morbidly obese patients seem to tolerate this
position well. Brodsky et al. (Anesthesiology 57:132,
1982) found that oxygenation during thoracotomy in
the LDP and one-lung ventilation (FIO2 1.0) was
satisfactory.

Attenzione allo scivolamento!!!!
• Fermare opportunamente il
paziente;straps,velcro,fasce,ecc.

Infine…non dimentichiamoci della estubazione!!!
• Massima attenzione anche alla estubazione!
• “the majority (19 of 26) of the claims from extubation
or recovery were associated with a difficult intubation
on induction, obesity, and/or sleep apnea”(ASA
closed claims 2006)
• Quindi,prima di svegliare:
• Preossigenazione
• Recruitment +PEEP o NIV
• Inserimento di una guida se l’intubazione è stata
difficile..
• Altro???suggerimenti??

INTUBATION OF THE OBESE IN THE
ICU

SOLUZIONI PER INTUBAZIONE:ILMA

The Mallinckrodt PVC tracheal tube’s (7.0-mm internal diameter)
natural bend was oriented in two different ways when inserting it in the
intubating LMA. As a result, the angle that the tip of the tracheal tube
emerged from the intubating LMA was 47° or 20°, respectively.
Tao Zhu.Conventional Endotracheal Tubes for Intubation Through the Intubating Laryngeal Mask
Airway.Anesth. Analg. January 1, 2007 104:213-214

The angle of 20° increases to 40° when mild force is applied or the tip
encounters resistance during tracheal intubation
Tao Zhu.Conventional Endotracheal Tubes for Intubation Through the Intubating Laryngeal Mask
Airway.Anesth. Analg. January 1, 2007 104:213-214

Tao Zhu.Conventional Endotracheal Tubes for Intubation Through the
Intubating Laryngeal Mask Airway.Anesth. Analg. January 1, 2007 104:213-214
• Our study revealed that the 20° angle was
associated with more frequent success for
endotracheal intubation (90%) than the 47° angle
(84%). It also resulted in less frequent sore throat
(19% vs 26%, respectively; Table 1). The overall
success rate with our method is about 87% in
patients with or without difficult airway. Our
experience indicates that the Mallinckrodt PVC
tracheal tube can be used as successfully as the
Rusch PVC tracheal tube for blind tracheal
intubation through the intubating LMA (1).

LMA CTrach
LMA CTrachTM (CT), a modified version of the intubatingLMA
FastrachTM,
allows continuous video-
endoscopy of the tracheal
intubation procedure.

Combes X, Sauvat S, Leroux B, et al. Intubating laryngeal mask airway
in morbidly obese and lean patients: a comparative study.
Anesthesiology. 2005;102(6):1106–1109
We demonstrated
that the safety
and efficiency of
the ILMA were
comparable
between
lean and obese
patients, but
according to
quality criteria,
airway
management was
simpler in obese as
compared
with lean patients

• metal handle may be the result of better spontaneous pharyngeal placement of the mask because of the reduced pharyngeal
caliber that can be observed in obese patients. Magnetic resonance imaging has shown a decreased
pharyngeal area and volume in obesity associated with the deposition of adipose tissue,
predominantly in the lateral pharyngeal walls.23,24 These lateral fat columns might serve to
guide or railroad the ILMA into place during its descent into the pharynx and stabilize its
position after cuff inflation. This hypothesis may explain why a sealed airway was more
frequently obtained in obese patients as compared with lean patients.
• However, Archie Brain, M.D. (personal verbal communication, 46e Congrès de la Socie´te´ Franc¸aise d’Anesthe´sie et
Re´animation, Club Respiratoire, Paris, France, September 2004), noted that in normal patients, with the ILMA as opposed to
the standard laryngeal mask airway, the narrow convex posterior part of the ILMA, combined with the rigidity of its airway tube,
seemed to cause the mask to slip more easily to one side or the other of the oppositely curved midline cervical bodies. He
suggested that this tendency might be a factor causing occasional misalignment of the mask with the laryngeal aperture. We
believe that these observations may account for our higher incidence of airway-adjustment maneuvers and failed blind
intubation attempts in lean patients, resulting in longer and more difficult airway management in some of these patients.

Frappier J, Guenoun T, Journois D, Philippe H, Aka E, Cadi P, Silleran-Chassany
J.Airway management using the intubating laryngeal mask airway for the
morbidly obese patient. Anesth Analg. 2003 ;96(5):1510-5
The level of clinician experience for this technique does not seem to influence either the
mean duration or the number of attempts required to achieve adequate ventilation or
tracheal intubation. Thus, airway management with the ILMA is easily achieved, even by
inexperienced practitioners in obese patients in whom difficult mask ventilation and
tracheal intubation is common
success rate of successful tracheal intubation with ILMA was 96.3%.
Attempt number and total duration of the procedure were not different among patients with low-grade
(Cormack 1-2) and patients with high-grade (Cormack 3-4) laryngeal views.
The time required for insertion of the ILMA was slightly longer in patients with high-grade laryngeal views

ILMA in obese and out of hospital
• .
• Combes X, Leroux B, Jabre P, Margenet A, Dhonneur G.Out-of-hospital rescue
oxygenation and tracheal intubation with the intubating laryngeal mask airway in
a morbidly obese patient. Ann Emerg Med. 2004 Jan;43(1):140-1
• .
• Lavoro tedesco ………….

Wender R, Goldman. . AJ.Awake insertion of the fibreoptic intubating
LMA CTrach in three morbidly obese patients with potentially
difficult airways.Anaesthesia. 2007 Sep;62(9):948-51
• ILMA,+ integrated fibreoptic bundle that provides a view of the larynx.
• This enables visualisation of tracheal intubation while delivering 100%
oxygen, with or without an inhalational anaesthetic
• We report awake insertion of the CTrach in three morbidly obese patients
(BMI 60-63) with known or anticipated difficult airways.
• midazolam + glycopyrrolate i.v.
• topical lidocaine 4%.
• CTrach was inserted into the oropharynx of the still-awake patient
• the vocal cords were visualised
• anaesthetic induction was commenced with sevoflurane and spontaneous
ventilation
• we were able to see the vocal cords during the entire anaesthetic
induction and intubation
• Patients very satisfied

Dhonneur G, Ndoko SK, Yavchitz A, Foucrier A, Fessenmeyer C, Pollian C, Combes X,
Tual L.Tracheal intubation of morbidly obese patients: LMA CTrach vs direct
laryngoscopy.Br J Anaesth. 2006 Nov;97(5):742-5.
• LMA CTrach (CT), a modified version of the intubating LMA Fastrach, allows continuous video-endoscopy of the tracheal intubation
procedure. We tested the hypothesis that the CT is efficient for tracheal intubation of morbidly obese patients who are at risk of a
difficult airway.
• METHODS:
• After Ethics' Committee approval, 104 morbidly obese patients (BMI >35 kg m(-2)) scheduled for bariatric surgery were included in this
prospective study. Patients were randomly assigned in two groups: tracheal intubation using direct laryngoscopy (DL) or the CT.
Induction of anaesthesia was standardized using sufentanil, propofol and succinylcholine. Characteristics and consequences of airway
management were evaluated.
• RESULTS:
• Preoperative characteristics of patients and consequences of anaesthesia induction on physiological variables were similar in both
groups. Difficulty in facemask ventilation was similar in both groups. Tracheal intubation was successfully carried out with DL and CT.
Forty-nine per cent of the patients from the CT group required laryngeal mask manipulation (ventilation and view optimization)
resulting in increased duration of tracheal intubation by 57 s as compared with DL. Oxygenation was of better quality in the patients
managed with CT than with DL. Blind tracheal intubation was mandatory in eight (17%) patients of the DL group, while tracheal
intubation was seen in all patients of the CT group.
• CONCLUSION:
• We demonstrated in morbidly obese patients that trachealintubation performance of the CT
was superior to that of DLbecause it allowed systematic visualization of the tracheal
intubation. This promoted better oxygenation during the procedure.
• In comparison with previous data obtained in morbidly obese patients using ILMA our results
with CT suggest that additional visualization of laryngeal structure allowed optimization of
placement of the mask in the pharynx. This results in reduced tracheal intubation attempts
and a 100% tracheal intubation success rate. Such a high success rate for visualized tracheal
intubation was not systematically obtained with CT in recent studies.

Dhonneur G, Ndoko SK, Yavchitz A, Foucrier A, Fessenmeyer C, Pollian
C, Combes X, Tual L.Tracheal intubation of morbidly obese patients:
LMA CTrach vs direct laryngoscopy.Br J Anaesth. 2006
Nov;97(5):742-5.

Airway management data with the LMA Ctrach
Dhonneur G, Ndoko SK, Yavchitz A, Foucrier A, Fessenmeyer C, Pollian C, Combes X, Tual L.Tracheal intubation of
morbidly obese patients: LMA CTrach vs direct laryngoscopy.Br J Anaesth. 2006 Nov;97(5):742-5.

Dhonneur G, Ndoko SK, Yavchitz A, Foucrier A, Fessenmeyer C, Pollian
C, Combes X, Tual L.Tracheal intubation of morbidly obese patients:
LMA CTrach vs direct laryngoscopy.Br J Anaesth. 2006
Nov;97(5):742-5.
• Three manoeuvres applied with the metal handle and performed with the cuff
remaining inflated, derived from those described by the inventor of ILMA1 were
used to resolve ventilation problems and unsatisfactory visualization:
• Chandi, down–up–down (DUD): the laryngeal mask is blocked
distal in the pharynx, then it is removed by approximately 3–6
cm and replaced more distal)
• medial– lateral–medial (MLM): smooth lateralization of
the laryngeal mask in the pharynx in which depth of insertion
does not vary).
• With glottis view optimized, a reinforced flexible tracheal tube was inserted
through the airway tube and railroaded in the trachea. In case of impossible
glottisvisualization after two insertions or in case of impossible intubation with the
CT correctly placed, DL was proposed.

Table :Success rate of intubation through direct
visualization with the LMA C trach
author Success rate Notes:
Dhonneur BJA 2006 100% Manipulation 31%
Timmermann BJA 2006 92 Manipulation 63%
Timmermann Anesthesist
2006
84 Journal Not found
Freid AnesthClin N.Am
2005
80 Review article
Timmermann A, Russo S, Graf BM. Evaluation of the CTrachTM—
an intubating LMA with integrated fibreoptic system. Br J Anaesth
2006; 96: 516–21
Timmermann A, Russo S, Natge U, Heuer J, Graf BM. LMA
CTrachTM: Initial experiences in patients with difficult-to-manage
airways. Anaesthesist 2006; 55: 528–34
Freid EB. The rapid sequence induction revisited: obesity and sleep
apnea syndrome. Anesthesiol Clin North America 2005; 23: 551–64

VIDEOLARYNGOSCOPY:AIRTRAQ,RU
SCH,……

Obesity Surgery Volume 19, Number 8, 1096-1101
Video-Assisted Versus Conventional Tracheal Intubation in Morbidly Obese
Patients . Dhonneur G, Abdi W, Ndoko SK, Amathieu R, Risk N, El Housseini L, Polliand
C, Champault G, Combes X, Tual L.
• Anesthesiology and Intensive Care Medicine Department, Jean Verdier Public
University Hospital of Paris (APHP), 93143, Bondy, France.
gilles.dhonneur@jvr.aphp.fr
• tracheal intubation characteristics and arterial oxygenation quality during airway management of morbidly obese
patients whose trachea was intubated under video assistance with the LMA CTrach (SEBAC, Pantin, France) or the
Airtraq laryngoscope (VYGON, Ecouen, France) with that of the conventional Macintosh laryngoscope.
• After standardized induction of anesthesia, 318 morbidly obese patients scheduled for elective morbid obesity
surgery received tracheal intubation with the LMA CTrach, the Airtraq laryngoscope, or the conventional
Macintosh laryngoscope
• Duration of apnea, time to tracheal intubation, and oxygenation quality during airway management were
compared between the LMA CTrach and the laryngoscope groups.
• The success rate for tracheal intubation was 100% with the LMA CTrach and the Airtraq laryngoscope. One
patient of the Macintosh laryngoscope group received LMA CTrach intubation because of early arterial oxygen
desaturation associated with unstable facemask ventilation.
• The duration of apnea was shorter with the LMA CTrach than that of the Airtraq laryngoscope and the Macintosh
laryngoscope.
• The duration tracheal intubation was shorter with the Airtraq laryngoscope than with the Macintosh
laryngoscopes and the LMA CTrach.
• During airway management, arterial oxygenation was of better quality with the LMA CTrach and the Airtraq
laryngoscope than that of the Macintosh laryngoscope.
• CONCLUSION: Because LMA CTrach promoted short apnea time and the Airtraq laryngoscope allowed early
definitive airway, both video-assisted tracheal intubation devices prevented most serious arterial oxygenation
desaturation evidenced during tracheal intubation of morbidly obese patients with the conventional Macintosh
laryngoscope

European Journal of Anaesthesiology 2007; 24: 1045–1049
Videolaryngoscopy improves intubation condition in morbidly
obese patients.J. Marrel, C. Blanc, P. Frascarolo, L. Magnusson
• The videolaryngoscope used was a Ru¨sch videolaryngoscope (X-Lite Videolaryngoscope, Ru¨ sch
Medical, Germany) with the light source at the tip of the blade. The screen is mobile, as a laptop
screen, 20 cm in diameter..
• 80 morbidly obese patients undergoing bariatric surgery.
• randomly assigned to one of two groups:One group was intubated with the help of the
videolaryngoscope and in the control group the screen of the videolaryngoscope was hidden to the
intubating anaesthesiologist.
• The primary end-point of the study was to assess in both groups the Cormack and Lehane direct and
indirect grades of laryngoscopy.
• The duration of intubation, the number of attempts needed as well as the minimal SPO2 reached
during the intubation process were measured.
• Results:
• Grade of laryngoscopy was significantly lower with the videolaryngoscope compared with the direct
vision (P,0.001). When the grade of laryngoscopy was higher than one with the direct laryngoscopy , it
was lower in 28 cases with the videolaryngoscope and remained the same only in two cases (P,0.001).
• The minimal SPO2 reached during the intubation was higher with the videolaryngoscope but it did not
reach statistical significance.
• The duration of intubation was significantly shorter with the videolaryngoscope than with direct view
(59631 s (range: 30–208) vs. 93670 s (range:40–450)) (P50.006).
• The minimal SPO2 was 98.26 0.8% with the videolaryngoscope and 97.16 with direct view (P50.075).
Conclusions: In morbidly obese patients, the use of the videolaryngoscope
significantly improves the visualization of the larynx and thereby facilitates
intubation.

Anesthesia technique of
European Journal of Anaesthesiology 2007; 24: 1045–1049.Videolaryngoscopy improves intubation condition
in morbidly obese patients.J. Marrel, C. Blanc, P. Frascarolo, L. Magnusson
• no premedication
• In the operating room, a special pillow was put under the patients’
shoulders in order to ramp up the patient’s shoulders, and the head
and the neck was extended in a sniffing position.
• 5 min. preoxygenation with 100% oxygen with a tight facemask was
• performed.
• Anaesthesia was then induced with propofol (1.5–2.5 mg/ kg
followed by a continuous infusion of propofol at 4–6 mg/ kg/ h
• and remifentanil at 0.25 microg /kg/ min
• Patients received cisatracurium 0.2 mg/ kg to facilitate intubation.
Muscle relaxation was evaluated with a nerve stimulator placed on
the ulnar nerve.
• When TOF response was 0, laryngoscopy was performed.

Ndoko SK, Amathieu R, Tual L, Polliand C, Kamoun W, El Housseini L, et al. Tracheal
intubation of morbidly obese patients: a randomized trial comparing performance
of Macintosh and Airtraq TM laryngoscopes. Br J Anaesth 2008;100:263-8
the AirtraqTM
laryngoscope
shortened the
duration of
tracheal
intubation and
prevented
reductions in
arterial oxygen
saturation in
morbidly obese
patients

ANCHE LA PROSEAL FUNZIONA
NEGLI OBESI….

Keller C, Brimacombe J, Kleinsasser A, Brimacombe L. The Laryngeal Mask Airway
ProSeal(TM) as a temporary ventilatory device in grossly and morbidly obese patients
before laryngoscope-guided tracheal intubation. Anesth Analg. 2002 Mar;94(3):737-40
• We determined the efficacy of the laryngeal mask airway ProSeal(TM) (PLMA) as a temporary ventilatory device in
morbidly obese patients before laryngoscope-guided tracheal intubation. Sixty patients (body mass index 35--60
kg/m(2)) scheduled for elective surgery, who preferred airway management under general anesthesia, were
studied. The induction of anesthesia was with midazolam/fentanyl/propofol and maintenance was with
sevoflurane 1%--3% in oxygen 100%. The PLMA was inserted and an effective airway established. Rocuronium was
given IV for paralysis. Oropharyngeal leak pressure, ease of gastric tube placement, residual gastric volume,
fiberoptic position of the airway/drainage tube, and ease of ventilation at a tidal volume of 8 mL/kg was
determined. The PLMA was then removed and laryngoscope-guided tracheal intubation attempted. The number
of insertion/intubation attempts (maximum two each) and time taken to establish an effective airway with each
device were recorded. An effective airway was obtained at the first insertion attempt in 90% of patients (54/60)
and at the second attempt in 10% (6/60). The time taken to provide an effective airway was 15 plus minus 7 s (7--
42 s). Oropharyngeal leak pressure was 32 plus minus 8 cm H(2)O (12--40 cm H(2)O). The residual gastric volume
was 36 plus minus 46 mL (0--240 mL). Positive pressure ventilation without air leaks was possible in 95% of
patients (57/60). The vocal cords were seen from the airway tube in 75% of patients (45/60), but the esophagus
was not seen. The fiberoptic view from the drainage tube revealed mucosa in 93% of patients (56/60) and an open
upper esophageal sphincter in 7% (4/60). Tracheal intubation was successful at the first attempt in 90% of patients
(54/60), at the second attempt in 7% (4/60), and failed in 3% (2/60). In these latter two patients, the PLMA was
reinserted and surgery performed uneventfully with the PLMA. The time taken to tracheally intubate the patient
was 13 plus minus 10 s (8--51 s). There were no episodes of hypoxia (SpO(2) <90%) or other adverse events. There
were no differences in insertion success rate, or the time to successful insertion between the PLMA and
laryngoscope-guided intubation. We conclude that the PLMA is an effective temporary ventilatory device in
grossly or morbidly obese patients before laryngoscope-guided tracheal intubation. IMPLICATIONS: The laryngeal
mask airway ProSeal(TM) is an effective temporary ventilatory device in grossly and morbidly obese patients
before laryngoscope-guided tracheal intubation

Keller C, Brimacombe J, Kleinsasser A, Brimacombe L. The Laryngeal Mask Airway
ProSeal(TM) as a temporary ventilatory device in grossly and morbidly obese patients
before laryngoscope-guided tracheal intubation. Anesth Analg. 2002 Mar;94(3):737-40
• Anesthesia technique:
• Ranitidine per os 1.5 h preoperatively.
• Monitoring was applied before induction and included an
electrocardiograph,pulse oximeter, gas analyzer, arterial line, tidal volume monitor,
airway pressure monitor, and peripheral nerve stimulator.
• Anesthesia was given with the patient in the supine position with the
patient’s head on a standard pillow 8 cm in height.
• Midazolam 0.02 mg/kg and fentanyl 1 microg/kg were administered.
• Patients were preoxygenated for 5 min.
• Anesthesia was induced with propofol 2–3 mg/kg given over 30 s, and the PLMA
inserted when there was no response to jaw thrust (5). Additional boluses of
propofol 0.5 mg/kg were given as required until an adequate level of anesthesia
was achieved for placement.
• Anesthesia was maintained with sevoflurane 1%–3% in oxygen 100%.
• Face mask ventilation was performed if conditions for insertion were not suitable
within 30 s of completion of the induction dose.
• The size 5 PLMA was inserted/fixed according to the manufacturer’s instructions

Conclusioni sui presidi alternativi
• ILMA,C trach,Airtraq sono superiori
alla laringoscopia diretta negli obesi !
• facilitano la intubazione con
maggiore sicurezza perché
permettono la ossigenazione durante
le manovre
• Meglio acquisire esperienza con
questi devices!!!
• (ma è importante il training…..)

Pro/cons awake intubation
advantages
awake Asleep
breathing
Asleep not
breathing
Airway tone maintained yes No No
Spontaneous breathing preserved yes yes No
Patient can protect airway against
aspiration
yes No No
Protection of neurological status yes ? No
Easier localization of glottic opening when
air is coming out(bubbles)
yes Yes/no no
Avoidance of cardiovascular depression yes No no
Patient cooperation :protude tongue,deep
breath,jaw movement…
yes no no
Disadvantages
Time consuming yes yes no
Patient discomfort yes no no

awake tracheal intubation:when,why,how…l
• When? Rosenblatt tree
– clinical judgment
– preoperative airway assessment
• predicted levels of difficulty for both tracheal intubation and mask
ventilation
– aspiration risk
– availability of equipment and assistance
– individual’s self-assessment of his or her own skill, knowledge, and familiarity
with MO.
• Why?
• knowledge of the anatomical and physiological characteristics of obesity
that provide an understanding of why problems can arise.
• How??
• management strategies
• airway adjuncts and techniques

Rosenblatt WH. The Airway Approach Algorithm: a decision
tree for organizing preoperative airway information. J Clin
Anesth. 2004;16(4):312–316.
• Rosenblatt logical way
–Airway Approach Algorithm.
– Responses to five clinical questions determine the
entry point into the DAA.
• 1. Must the airway be managed?
2. Is there potential for difficult laryngoscopy?
3. Can supralaryngeal ventilation be used?
4. Is the stomach empty?
5. Will the patient tolerate an apneic period?

A negative answer to any
question directs the clinician to a
root point of the DAA.(diff.air.algor)
A positive answer leads the
operator to the next question.

Must the airway be managed?
Avoidance of a general anesthetic is desirable for surgical
patients with obesity since a regional anesthetic will minimize
cardiorespiratory risks and shorten recovery time.
• regional anesthesia is technically challenging in patients with
MO and failure rates are high
• regional anesthesia may not be appropriate for a particular
operation.
• Sedation techniques in patients with MO require great care
since hypoxia will occur at even light levels and airway
obstruction and collapse is a risk.
• For patients with MO requiring general anesthesia the airway
should be secured with either a tracheal tube or laryngeal
mask airway (LMA).

Corso aaroi besity intubation

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