Weaning Mechanical Ventilation Weaning Failure RSBI SBT PSV Criteria of weaning Extubation Cuff Leak test

2. The process of transferring totalor partial ventilatory support from
ventilator to the patient full control
 Weaning is a gradual process but may be abrupt
Weaning, liberation, discontinuation, separation
Withdrawal of MV that leads to death

3.  From MV (mainly)
 From ETT or return to baseline
 From Oxygen or return to baseline

4.  Simple:
Discontinuation after 1st assessment
 Difficult:
Discrimination within 2-7 days of initial
assessment
 Prolonged:
> 7 days of initial assessment

5.  10-15% weans over 3 days
 5-10% needs gradual prolonged weaning
 1% remains ventilator dependent

6.  Before weaning, patients should partially or
completely improved from his underlying
disease which lead to MV with new events
that occurred MV necessitating the delay of
weaning process
 30-50% of MV is spent in weaning

7.  Fast weaning is less dangerous than slow
weaning
 75-80% of MV needs no slow weaning
 Do not go on with weaning that is failing, do
not wean to fatigue
 Rule of Thumb: Weaning should start as early
as possible

8.  Infection
 Deconditioning
 Cost
 Sedation
 VALI
 Airway trauma
 Psychological (depression, lack of confidence, lack
of ambition, lack of sleep, psychosis)

9. (17%)
Unintended accidental extubation during MV:
Iatrogenic (Phycian or Nurse)
(83%)
The same but by the patient
 80% of self-extubation DO NOT need re-
intubation
 In general 15% reintubation is accepted

10. It requires:
 Patient,
 Physician,
 Nurse, and
 Family collaborative efforts

11.  No precise criteria for weening failure
 Weaning failure means: Non-satisfactory or
insufficient resolution of the underlying
condition vs a New problem

12.  Patients with difficult and prolonged MV have
higher mortality rates (25%) than other ICU
patients (15%)
 30% of patients who fulfil criteria of weaning
fail to wean
 5-20% of MV patients need reintubation

13.  Resolution
 Adequate gas exchange
 RR less than or equal 35
 Temperature less than or equal 38
 Hb 8-10 gm/dl
 Stable Cardiovascular system
 Adequate neurological and muscular status
 HR less than or equal 140
 SBP <180>90

14.  Although >38-38.5 was excluded from
large weaning trials, itself is not used to
preclude SBT
< 10gm/dl is 5 times more common to fail
SBT compared to > 10gm/dl
 It is not good to hold SBT based only on <
10gml/dl

15.  NOT every patient with shock and or
vasopressors needs MV or intubation
 In patients with shock and vasopressors: It is
wise to slow or postpone weaning and
extubation
 Weaning failure is more common in AMI and
Ischemic ECG
 Optimal timing of weaning is not well-studied
in AMI

16. It is the parameters used to evaluate the readineaa
for weaning and predicting its success:
 Clinical
 Ventilatory
 Oxygenation
 Pulmonary reserve

17.  Clinical improvement
 Adequate cough
 Less secretions
 Hemodynamic stability

18.  PaO2 > 60mmHg
 SaO2 > 88%
 PaO2/FiO2 > 150-200 (P/Fratio)
 Qs/Qt < 20%
 P (A-a) O2 < 350 at FiO2=1

19.  Can tolerate 30 min of SBT
 PaCO2 within baseline
 VC > 10ml/kg
 Vt > 5mg/kg
 Can double his Vt
 RR <30- 35
 RSBI < 100 (105) b/min/L
 VE < 10L/min

20.  MIP > 20-30 cmH2O (<20(~100%failure,
>20(40%success))
 St Compliance > 30 ml/cmH2O (Vt/Pplat-PEEP)
 Vd/Vt , 60% on tube
 P 0.1 < 6 cmH2O
 O2 COB less than 15% of total O2 COB

21.  Vt
 RSBI (RR/Vt in liters)
 MIP
 RR
 VE (minute ventilation) (weakest)

22.  > 100 ===== 95% failure rate
 < 100 ===== 80% success rate
 Measured within one minute of discontinuation
of MV

23.  MV > 8 days
 COPD
 Elderly
Increased RSBI > 20% during SBT is better in
prognosis than absolute value

24. 1. CROP= (CdynxMIPx(PaO2/PAO2))/Raw
(> 13 ml/breath/min)
 CROP index has 100% sensitivity and 70%
specificity
2. Inspiratory Effort Quition (IEQ)=
{(0.75Vt/Cdyn)xTi/Ttot}/MIP
IEQ>10.15----- Weaning failure
3. P 0.1/MIP < 0.3------ successful weaning

25.  If the vertical excursion is less than 1 cm------
24-82% weaning failure rate even if the patient
is fulfilling other weaning criteria

26.  Communicate with patient
 Explain
 Calm environment
 Dedicated nurse
 Record baselines
 Raise HOB
 Tube suctioning
 Morning ?
 Family ?

27.  PSV
 CPAP
 APRV
 SIMV
 NAVA
 ASV
 SkilledPhysician weaning is better than any weaningmode
 Nurse or Protocol Driven Protocols

28.  May be up to 40 cm H2O (generally)
 Usually 5-15
 If PSV ≦ 8 and Vt ≧5 ml/kg and RR ≦25== Wean
 Decrease PSV 2-3 per time, every 30 min to 2 hours

29.  SBT (30-120 min)
 77-85% of successful SBT need no reintubation

30.  Wait 24 hours
 Repeat
 If 2 SBT done daily, NO more success than
once daily

31.  Better than unassisted SBT as it helps
overcome mechanical WOB imposed by
tubings and secretions
 (Both are as effective as each other)

32. Is not performed in:
 Bradycardia needing pacemaker
 Sinus tachycardia >140
 Sustained tachyarrhythmia

33.  Diaphoresis, anxiety
 PaO2 < 60 or FiO2 > 50
 PaCO2 > 10 mm Hg from baseline
 pH < 7.3 or > 0.07 decrease
 RR > 35
 HR > 140 or 20% increase
 SBP > 180 or 30% increase, or 20% decrease
 DBP ↓↑ 10%
 Arrhythmias
 PVCs > 4-6/min

34.  Decrease rate of weaning failure
 Decrease rate of reintubation
 Decrease HAP
 Helpful in COPD
 Decrease days of MV
 Decrease ICU days
 Decrease LOS
 Increased survival

35. Re-institution of MV within 48 hours of MV
1. ↑ Resistance
2. ↓ Compliance
3. Respiratory muscle fatigue

36.  Hypoxaemia (so important)
 Increased ventilatory demands
 Increased Resistive WOB
 Increased Elastic WOB
 Decreased muscular or ventilatory drive
 Psychological

37.  Increased CO2 production (sepsis, overfeeding,
fever, hypothyroidism)
 Metabolic acidosis (RF, keto or lactic acidosis)
 Anxiety
 Pain
 Hypoxemia
 Increased Vd, DH, PE, Volume depletion

38.  Pneumonia
 DH
 Atelectasis
 Effusion
 Pneumothorax
 Abdomenal distension

39.  Bronchoconstriction
 Narrow ETT
 Secretions
 Tubings

40.  Critical illness polyneuropathy
 Ventilator induced diaphragmatic dysfunction
 Drugs
 Hypothyroidism
 Electrolyte Imbalance
 Sepsis
 Adrenal insufficiency
 Malnutrition
 Metabolic alkalosis
 OHS

41.  Baseline:
pH 7.38, PaCO2 58, HCO3 34
 Respiratory Failure:
pH 7.24, PaCO2 76, HCO3 36
 On MV:
pH 7.56, PaCO2 40, HCO3 34
 3 Days of MV:
pH 7.40, PaCO2 40, HCO3 24
 Weaning ng:
pH 7.24, PaCO2 58, HCO3 26

42.  ETT increase Raw by 50-240% according to tube size
 8 Gauge ETT has cross-sectional area of 50 mm2
while the adult glottis which is the narrowest part of
airways is 66 mm2
 ETT may be cut to one inch from patients lips

43. Worsened by:
 Malnutrition
 Aminoglycosides
 Glucocorticoids
 Muscle relaxants
 Electrolyte Disturbance
 Thyroid dysfunction
No known drug to improve respiratory muscle function

44. In Failure-To-Wean (esp. COPD):
 Acetazolamide 250x2x10-------may be
 Donepezil 10mgx1x10-------may be
 Nitroglycerine IV in hypertensives during weaning------may be
 Anabolic steroids (Nanrolone with high caloric diet)------low to
no (untested)
 Medroxyprogesterone------low to no
 Almitrine-------- Not now
 Levosimendan: showed promising improvement in
respiratory muscle contraction in healthy people

45.  Tracheostomy
 Rehabilitation
 Specialized units
 Home ventilation
 Terminal weaning

46.  It and its timing do not reduce mortality, HAP
or duration of MV
 May be helpful in:
1. Less sedation (Faster weaning)
2. Lower Airway resistance
3. In prolonged MV.... better physiotherapy

47. needs:
 Appropriate conscious level
 Intact cough reflex
 Intact gag reflex
 Cooperation

48.  In Volume Controlled Mode:
Breath with Inflated Cuff,report Vt exp, Then deflate the
cuff, report Vt exp again
Stridor or The difference less than 130ml:
There is laryngeal edema.
 Discontinue the ventilator from the ETT, block it
completely with your hand with cuff deflated, notice if
there is air entry (stethoscope larynx or chest)

49. If MV > 6 days
 Give systemic steroids 4-6 hours before extubation
and/or Nebulized Racemic Adrenaline
Risk factors for laryngeal edema:
 Female sex
 MV > 10 days
 Re-intubation
 Traumatic intubation
 Large ETT

50.  8 folds increase in HAP
 6 folds increase in death