General anesthesia

GENERAL ANESTHESIA
P R E S E N T E D B Y –
D R . S W AT I S A H U

• Defination
• Introduction
• History
• Indications
• Levels of sedation
• Goals of sedation
• Sequence of depression of CNS
• Stages of anaesthesia
• Mechanism of action of GA
CONTENTS

• Pre- anesthetic evaluation
• Pre-operative preparation
• Anaesthetic Equipments
• Pharmacology of anaesthetics
• Muscle relaxants
• Post operative care
• Complications of GA.
• Conclusion
CONTENTS

GENERAL
ANESTHESIA
• It is a controlled state of unconsciousness accompanied by partial or complete loss of protective
reflexes including the inability to independently maintain an airway or respond purposefully to
verbal command.
LOCAL
ANESTHESIA
• Reversible loss of sensation in circumscribed area of body caused by depression of excitation in
nerve endings or an inhibition of conduction process in peripheral nerves.
CONSCIOUS
SEDATION
• It is a state of mind obtained by IV administration of combination of anxiolytics, sedatives and
hypnotics &/or analgesic that render the patient relaxed, yet allows the patient to communicate,
maintain patent airway and ventilate adequately.

• General anesthetics (GAs) are drugs which causes :
Reversible loss of all sensations and
consciousness.
Loss of memory and awareness with insensitivity
to painful stimuli, during a surgical procedure.
INTRODUCTION
Areflexia

Providing office based sedation, anxiolysis and
analgesia to the OMFS patient’s has been
standard practice for decades
The goal has been to establish an environment in
which the patient is comfortable and cooperative
and hemodynamically stable.
Charles F. Cangemi, Jr, Administration of General Anesthesia for Outpatient Orthognathic Surgical
Procedures American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 69:798-
INTRODUCTION

• The focus has also been on rapid patient recovery with
efficient use of time
• Numerous advancements in pharmacology, equipments and
techniques over the years provides the surgeon with various
alternatives.
INTRODUCTION

• Alcohol is the oldest known sedative. It was used in
the ancient Mesopotamia thousands of years ago.
• 3400 B.C. - The ‘Euphoric’ effect of Opium was
discovered by Summerians.
• Joseph Priestly(1733-1804)- discoverd various gases
like- nitrous oxide, ammonia,oxygen.
T. Y. Euliano,J. S. Gravenstein, Essential Anesthesia -From Science to Practice:United States of America by
Cambridge University Press, New York;2004: Introduction A very short history of anesthesia;p.1-4
HISTORY

• 1801-Humphry Davy
- Anesthetic properties of nitrous oxide.
-Coined the term ‘laughing gas’.
• 1804- Friedrich Serturner- isolated morphine from opium.
• Dec 10,1844- Sir Horace Well attended lecture on ‘Chemical
Phenomenon’ by Gardner.(nitrous oxide)
HISTORY

• Dec 11,1844, Nitrous oxide
was administered to Dr.
Horace Well, rendering him
unconcious & able to have
wisdom tooth extracted
without awareness of pain.
HISTORY

• 16th oct, 1846, ether was
administered by Sir William
Morton for the removal of
mandibular tumor.
• Experiment was published in
Boston daily journal. And led
to the discovery of Surgical
anesthesia.
HISTORY

PROPERTIES OF
IDEAL
ANESTHETICS

P R O P E R T I E S O F
I D E A L A N E S T H E T I C S
 For the patient –
Should be pleasant,
Non irritating,
Should not cause nausea orvomiting.
Induction and recovery should be fast with no after
effects.
 For the surgeon –
Should provide adequate analgesia,
Immobility and muscle relaxation.
It should be noninflammable and nonexplosive so
that cautery may be used.

 For the anaesthetist –
Its administration should be easy, controllable and
versatile.
Margin of safety should be wide - no fall in BP.
Heart, liver and other organs should not be
affected.
It should be potent so that low concentrations are
needed and oxygenation of the patient does not
suffer.
Rapid adjustments in depth of anaesthesia should
be possible.
It should be cheap, stable and easily stored.
It should not react with rubber tubing or soda
lime.

• The surgical procedures of larger magnitude, which cannot be accomplished under
local anesthesia or where the regional anesthesia and / or sedation are inadequate to
provide satisfactory analgesia.
• When the patients are uncooperative.
• When patient compliance is not required.
• Apprehensive patients where muscle relaxation is required for stabilization.
INDICATIONS

MINIMAL
SEDATION
MODERATE
SEDATION
DEEP
SEDATION
GENERAL
ANESTHESIA
Anesthesia in outpatient facilities, Parameters of Care:Clinical Practice Guidelines for Oral and Maxillofacial
Surgery; J Oral Maxillofac Surg 70:e31-e49, 2012, Suppl 3
LEVELS OF SEDATION

• Minimal Sedation
(Anxiolysis)
A minimally depressed level of
consciousness, produced by a
pharmacologic method that retains
the patients ability to independently
and continuously maintain an airway
and respond normally to tactile
stimulation and verbal command.
Ventilatory and cardiovascular
fuctions are unaffected.
LEVELS OF SEDATION

• Moderate Sedation
(conscious sedation)
A drug-induced depression of
consciousness during which patients
respond purposefully to verbal
commands,either alone or
accompanied by light tactile
stimulation.No interventions are
required to maintain a patent airway,
and spontaneous ventilation is
adequate.Cardiovascular fuction is
usually maintained.
LEVELS OF SEDATION

• Deep Sedation
A drug-induced depression of
consciousness during which patients
be easily aroused, but respond
following repeated or painful stimulations.
The patient’s ability to independentely
maintain ventilatory function may be
impaired, and the patient may require
assistance in maintaining a patent airway.
Cardiovascular function is usually
maintained during deep sedation.
LEVELS OF SEDATION

• General Anesthesia
A drug-induced loss of consciousness-
during which patient is not arousable, even
painful stimulation. The ability to maintain
ventilatory function is impaired. Patients
require assistance in maintaining a patent
airway, and positive pressure ventilation may
be required because of a depressed
spontaneous ventilation or drug-induced
depression of neuromuscular function.
Cardiovascular function may be impaired.
LEVELS OF SEDATION

LEVELS OF SEDATION
Fonseca Raymond et al:Oral and maillofacial surgery;vol 1,2nd edition;saunders,an imprint of elsevier inc.St. Louis, Missouri.
2009;Chapter 5: anesthesia consept and techniques;p.67-76

• Provide an optimal environment for completion of surgical procedure.
• Minimize patient anxiety and optimize patient comfort.
• Control patient’s behaviour and movement and optimize patient cooperation.
• Optimize analgesia and minimize pain.
• Maximize the potential for amnesia.
• Optimize patient safety and maintain hemodynamic stability.
Fonseca Raymond et al:Oral and maillofacial surgery;vol 1,2nd edition;saunders,an imprint of elsevier inc.St. Louis,
Missouri. 2009;Chapter 5: anesthesia consept and techniques;p.67-76
GOALS OF SEDATION

CEREBRAL
CORTEX
CEREBELLUM
SPINAL
CORD
MEDULLARY
CENTERS
Fonseca Raymond et al:Oral and maillofacial surgery;vol 1,2nd edition;saunders,an imprint of elsevier inc.St.
Louis, Missouri. 2009;Chapter 5: anesthesia consept and techniques;p.67-76
SEQUENCE OF DEPRESSION IN CENTRAL NERVOUS
SYSTEM

• Arthur Ernest Guedel (1937)
Stage of
Analgesia
Stage of
Delirium
Surgical
anaesthesia
Medullary
paralysis
Schwartz J.Paul; Anesthesia:Oral and Maxillofacial clinics of North America; Volume 25, Issue 3,
Pages 341-536 (August 2013)
STAGES OF ANESTHESIA

STAGE
OF
ANALGESIA
• Starts from beginning of
anaesthetic inhalation and lasts
upto the loss of consciousness
• Pain is progressively abolished
• Reflexes and respiration remain
normal
• Use is limited to short procedures

STAGE OF
DELIRIUM
• From loss of consciousness to beginning of
regular respiration
• Patient may shout, struggle and hold his
breath; muscle tone increases, jaws are tightly
closed, breathing is jerky; vomiting,
involuntary micturition or defecation may
occur
• Heart rate and BP may rise and pupils dilate
due to sympathetic stimulation
• No operative procedure carried out
• Can be cut short by rapid induction,
premedication

STAGE
OF
SURGICAL
ANESTHESIA
• Extends from onset of regular respiration to
cessation of spontaneous breathing.
• This has been divided into 4 planes which
may be distinguished as:
Plane 1 rolling eye balls. This plane ends
when eyes become fixed.
Plane 2 loss of corneal and laryngeal reflexes.
Plane 3 pupil starts dilating and light reflex is
lost.
Plane 4 Intercostal paralysis, shallow
abdominal respiration, dilated pupil.

MEDULLARY
PARALYSIS
• Cessation of breathing to failure of
circulation and death.
• Pupil is widely dilated, muscles are totally
flabby, pulse is thready or imperceptible
and BP is very low

• Major target- Ligand gated ion channels.
• GABAA receptor gated Cl¯ channel.
Examples –
Many inhalation anesthetics,
barbiturates,
benzodiazepines and
propofol.
Hugh C. Hemmings jr et al; emerging molecular mechanisms of General anesthetic action; TRENDS in
pharmacological sciences vol.26 no.10 october 2005
MECHANISM OF ACTION Acts by
depressing
Synaptic
transmission

Other Mechanisms:
• Glycine – Barbiturates, propofol and others can activate in spinal
cord and medulla
• N – methyl D- aspartate (NMDA) type of glutamate receptors –
 Gates ca+ selective cation channel
 Nitrous oxide and ketamine selectively inhibits this receptor.
Hugh C. Hemmings jr et al; emerging molecular mechanisms of General anesthetic action; TRENDS in
pharmacological sciences vol.26 no.10 october 2005
MECHANISM OF ACTION

The fundamental process of taking detailed history
and performing a systematic clinical examination
remains the foundation on which preoperative
assessment relies, backed up by ordering appropriate
investigations where indicated.
James Cphero et al,pre operative, intraoperative and post operative assessment and monitoring,
Anesthesia:Oral and Maxillofacial clinics of North America; Volume 25, Issue 3, Pages 341-536
(August 2013)
PREANESTHETIC EVALUATION

• To Confirm that surgery proposed is realistic compared the likely benefit
with the possible risks .
• To obtain pertinent information about the patient’s medical history and
physical as well as mental condition.
• To determine the need for a medical consultation and the kind of
investigations required.
AIMS
(August 2013)
Use the ASA and GOLDMAN scale for anaesthetic
risk.

• To educate the patient about anaesthesia, anaesthetic technique and
post-operative care.
• To choose the anaesthetic plan to be followed, guided by the risk
factors uncovered by the medical history.
• Prescribe premedication and/ or other specific prophylatic measure if
required.
• To obtain informed consent.

1. Medical history questionnaire
2. Physical examination
3. Lab investigations
(August 2013)

1. Current problems
2. Other known problems
3. Treatment/medicines for the problems: dose, duration
and effectiveness
4. Current drugs use: reason, dose, duration, effectiveness
and side effect
5. History of drug allergies
6. History of use of tobacco—smoking or smokeless
tobacco or alcohol consumption, frequency, quantity
and duration
7. Prior anesthetic exposure: type and any adverse effects.
8. General health and review of organ systemsJames Cphero et al,pre operative, intraoperative and post operative assessment and monitoring,
(August 2013)
MEDICAL HISTORY QUESTIONAIRE

1. Vital Signs
2. Airway
3. Heart
4. Lungs
5. Extremities
6. Neurologic examination
(August 2013)
PHYSICAL EXAMINATION

• Pulse rate and Blood pressure (BP) should be checked to find out about any irregularity
of pulse or whether there is any deviation from the normal values of both.
• If there is rise in blood pressure from the normal values of 120-140 systolic and 60-80
of diastolic in adult, the patient might need treatment to bring it to normal value and
hence should be referred for further evaluation and management to physician.
VITAL SIGNS

Difficult airway defined to be one in-
“ Which a conventionally trained anesthesiologist
experiences difficulty with face mask ventilation of upper
airway, difficulty with tracheal intubation, or both.’’
Richard H. Haug, Henry H. Rowshan, Dale A. Baur; Atlas of the Oral & Maxillofacial Surg Clinics Of
North America: Management of Airway,vol 18 No.1, March 2010
AIRWAY

i. Patency of nares : look for masses inside nasal cavity (e.g. polyps)
deviated nasal septum, etc.
ii. Mouth opening of at least 2 large finger breadths between upper and
lower incisors in adults is desirable.
AIRWAY EVALUATION
GENERAL, PHYSICAL AND REGIONAL EXAMINATION

• iii. Teeth : Prominent upper incisors, or canines with or without
overbite, can impose a limitation on alignment of oral or pharyngeal
axes during laryngoscopy and especially in association with a large
of tongue, they can compound the difficulty during the direct
laryngoscopy or bag-mask ventilation. An edentulous state, on the
hand, can render axis alignment easier but hypopharyngeal
by the tongue can occur.

iv. Palate : A high arched palate or a long, narrow mouth may present
difficulty.
v. Assess patient’s ability to protrude the lower jaw beyond the upper
incisors (Prognathism).
vi. Temporo-mandibular joint movement : It can be restricted
ankylosis/fibrosis, tumors, etc.

vii. Measurement of submental space (hyomental/ thyromental length
should ideally be > 6 cm).
viii. Observation of patient’s neck : A short, thick neck is often
associated with difficult intubation. Any masses in neck, extension of neck,
neck mobility and ability to assume ‘sniffing’ position should be observed.
ix. Presence of hoarse voice/stridor or previous tracheostomy may
suggest stenosis.

x. Any systemic or congenital disease requiring special attention during
airway management
(e.g. respiratory failure, significant coronary artery disease, acromegaly,
etc.).
xi. General assessment of body habitus can yield important information.
xii. Infections of airway (e.g. epiglottitis, abscess, croup, bronchitis,
pneumonia).
xiii. Physiologic conditions : Pregnancy and obesity.

• Mallampati Classification
• Upper Lip Bite Test
• Atlanto occipital joint (AO) extension
• Thyromental Distance
• Sternomental Distance
• Mandibulo-hyoid distance
• Maximum vertical opening (MVO)
• LEMON airway assessment method
Richard H. Haug, Henry H. Rowshan, Dale A. Baur; Atlas of the Oral & Maxillofacial Surg
Clinics Of North America: Management of Airway,vol 18 No.1, March 2010
AIRWAY EVALUATION

UPRIGHT, MAXIMUM JAW
OPENING, TONGUE
PROTRUSION WITHOUT
PHONATION
MALLAMPATI TEST

https://www.speareducation.com/spear-review/wp-content/uploads/2014/05/Tonsil-Grading-
MALLAMPATI CLASSIFICATION Class I: the entire
palatal
arch,including the
bilateral faucial
pillars, are visible
down to their
bases.
 Class II: the upper
part of the faucial
pillars and most of
the uvula are
visible.
 Class III: only the
soft and hard
palates are visible.
 Class IV: only the
hard palate is
visible.

Class 1:
• Lower incisors can bite upper lip above vermillion line.
Class 2:
• Lower incisors can bite upper lip below vermillion line.
Class 3:
• Lower incisors cannot bite the upper lip
ULBT (UPPER LIP BITE TEST)

• It assesses feasibility to make sniffing or Magill position for intubation i.e. alignment of
oral, pharyngeal and laryngeal axes into an arbitrary straight line.
• The patient is asked to hold head erect, facing directly to the front, then he is asked to
extend the head maximally and the examiner estimates the angle traversed by the
occlusal surface of upper teeth.
• Any reduction in extension is expressed in grades:
 Grade I : >35°
 Grade II : 22°-34°
 Grade III : 12°-21°
 Grade IV : < 12°
• Normal angle of extension is 35° or more.
Atlanto occipital joint (AO) extension

https://i.ytimg.com/vi/blqwvuA7NKw/maxresdefault.jpg
THYROMENTAL DISTANCE
 Upright, neck
extension, mouth
closed, Distance <
6.5cm difficult
intubation
 The distance
between the
mentum and the
superior thyroid
notch.
 A distance greater
than 3 finger
breadths is
desirable.

THYROMENTAL DISTANCE

http://clinicalgate.com/wp-content/uploads/2015/04/B9780702035258000021_f02-03-
9780702035258.jpg
STERNOMENTAL DISTANCE
Extended head
and neck, mouth
closed, distance
<12.5cm is a
difficult
intubation

STERNOMENTAL DISTANCE

• Measurement of mandibular length from
chin (mental) to hyoid should be at least 4
cm or three finger breadths.
• It was found that laryngoscopy became
more difficult as the vertical distance
between the mandible and hyoid bone
increased.
MANDIBULO-HYOID DISTANCE

MAXIMUM VERTICAL OPENING (MVO)
 Generally greater than 2.5 to 3
fingerbreadths (depending on
observers fingers)
 Less than or equal to 2.5 cm is
considered a potentially difficult
intubation.

• The score with a maximum of 10 points is calculated by assigning
1 point for each of the following LEMON criteria:
 L = Look externally (facial trauma, large incisors, beard or
moustache, large tongue)
 E = Evaluate the 3-3-2 rule (incisor distance-3 finger breadths,
hyoid-mental distance-3 finger breadths, thyroid-to-mouth
distance-2 finger breadths)
 M = Mallampati (Mallampati score > 3).
 O = Obstruction (presence of any condition like epiglottitis,
peritonsillar abscess, trauma).
 N = Neck mobility (limited neck mobility)
• Patients in the difficult intubation group have higher LEMON
scores.
LEMON AIRWAY ASSESSMENT METHOD
LEMON airway assessment method ;
1 = Inter incisor distance in fingers,
2 = Hyoid mental distance in fingers,
3 = Thyroid to floor of mouth in
fingers

• Categories of difficult airway
1. Known or expected difficult airway.
2. Potentially difficult airway.
3. Unexpected difficult airway.
James Cphero et al,Adult Airway Evaluation in Oral Surgery, Anesthesia:Oral and Maxillofacial
clinics of North America; Volume 25, Issue 3, Pages 341-536 (August 2013)
AIRWAY EVALUATION

1. Known or expected difficult airway
• H/o difficult/failed intubation
• H/o difficult/failed mask ventilation.
• Conditions associated with difficult airway.
- Acquired and congenital
AIRWAY EVALUATION

2. Potentially difficult airway
• Limited neck extention.
• Limited mouth opening.
• Receding mandible.
• Mallampati class III or IV
• Short thyromental distance
AIRWAY EVALUATION

3. Unexpected difficult airway
• Supraglotic mass.
• Hyperplasia of lingual tonsils.
• Missed evidence of difficult airway
AIRWAY EVALUATION

EXAMINATION OF CVS
1) General Examination (CVS)
2) Examination of the Neck Veins
3) Examination of the Precordium

1)General Examination
Pallor
Icterus
Cyanosis
Clubbing
Edema
Temperature
Pulse
Respiratory
Rate
Blood
Lymphadenopathy

PALLOR (ANEMIA)
• The pallor of anemia is best seen in the mucous
membranes of the conjunctivae, lips and tongue and
in the nail beds
• Many causes of anemia can cause sinus
tachycardia, heart failure (Hyperdynamic)

CYANOSIS
This is a blue discoloration of the skin and mucous membranes caused by
increased concentration of reduced hemoglobin (5g/dl)
• Central cyanosis may result from the reduced arterial oxygen saturation caused by
cardiac or pulmonary disease.
• Intracardiac or extracardiac shunting.
• Cardiac causes include pulmonary edema and congenital heart disease. (e.g.
Fallot’s tetralogy).

• Peripheral cyanosis may result when cutaneous
vasoconstriction slows the blood flow and reduced oxygen
level in red blood cells.
• It is physiological during cold exposure.
• It also occurs in heart failure, when reduced cardiac output
produces reflex cutaneous vasoconstriction.

• Clubbing is painless soft-tissue swelling of
the terminal phalanges.
• congenital cyanotic heart disease
Infective endocarditis
CLUBBING

EDEMA
• Ed ema is tissue swelling due to
a n increase in interstitial fluid
• Pressure should be applied over a bony
prominence (tibia, lateral malleoli,
sacrum)
• Cardinal feature of congestive h e a r t failure.
• Edema is most prominent around th e ankles
in the amb u lan t patient a n d over th e sacrum
in th e bedridden patient

ARTERIAL PULSE
 Rate(recorded as beats per minute)
 Rh y th m (regular or irregular)
 Volume
 Character (thready, weak, bounding, full)
 Condition of t h e vessel wall
 Equality on both sides

BLOOD PRESSURE
 P a l p a t o r y Meth od
 Au scu lt at or y Met h o d
 Oscillatory Met h od

RESPIRATORY RATE
• Normal respiratory rate for an adult - 14 to 18 breaths per minute.
• Bradypnea (abnormally slow rate) may be produced by, among other causes, opioid
administration,
• Tachypnea (abnormally rapid rate) is seen with fever, fear (hyperventilation), and
alkalosis.
• The most common change in ventilation noted in the dental environment will be
hyperventilation, an abnormal increase in the rate and depth of respiration.
• The most common cause of hyperventilation in dental and surgical settings is extreme
psychological stress.

TEMPERATURE
• The “normal” oral temperature of 37.0° C (98.6° F) is only an average.
• The true range of normal is considered to be from 36.11° C to 37.56° C (97° F to 99.6°
F).
• Fever represents an increase in temperature beyond 37.5° C (99.6° F).
• Temperatures in excess of 38.33° C (101° F) usually indicate the presence of an active
disease process.
• Evaluation of the cause of the fever is necessary before treatment.
• If the patient’s temperature is 40.0° C (104° F) or higher, pretreatment medical
consultation is indicated.

• Body temperature should be maintained at or as near to normal as possible.
• Certain types of anesthetic agents are more commonly associated with excessive body
temperature changes.
• Low body temperatures, although generally less likely to develop during dental or
office-type anesthesia, may cause a delay in drug metabolism and patient recovery.
• High body temperatures may cause a hypermetabolic state and increase oxygen
consumption.

Precordium is the area of the chest wall lying in front of the heart.
 Inspection
 Palpation
 Percussion
 Auscultation
The subject should be examined in the recumbent and sitting position, and in good
light.
EXAMINATION OF T H E PRECORDIUM

 Inspection for Chest wall abnormalities
 Inspection for Position of trachea
 Inspection for Apex beat
 Inspection for Other pulsations
 Inspection for Dilated and engorged veins
 Inspection for Surgical or any Scars
INSPECTION

CHEST WALL (SKELETAL) ABNORMALITIES
 Precordial Bulging
 Pectus excavatum (funnel chest)
 Pectus carinatum (pigeon chest)
 Kyphosis (forward bending ofspine)
 Scoliosis (sideward bending of spine)
may displace the heart and affect palpation and
auscultation

APEX BEAT
LOWEST A N D TH E OUTERMOST POINT OF DEFINITE CARDIAC IMPULSE CAN BE
PALPATED.

DILATED AND ENGORGEDVEINS
 SVC or IVC obstruction
 Coarctation of aorta

 Palpation for Apex Beat (Position and Character)
 Palpation for Position of trachea
 Palpation for Parasternal Heave
 Palpation for Thrills
 Palpation for Direction of flow in veins
 Palpation for Tender points
PALPATION

 Auscultation for Heart Sounds
First sound (S1)
This corresponds to mitral and tricuspid valve closure at
the onset of systole.
Second sound (S2)
This corresponds to aortic and pulmonary valve closure
following ventricular ejection.
AUSCULTATION

Murmurs
Heart murmurs are produced by turbulent flow across a n abnormal
valve, septal defect or outflow obstruction.
 Timing
 Duration
 Character and pitch
 Intensity
 Location
 Radiation

1) General Examination (RS)
2) Examination of the Chest
EXAMINATION OF THE
RESPIRATORY SYSTEM
UPPER RESPIRATORY TRACT LOWER RESPIRATORY TRACT

2) EXAMINATION OF THE CHEST
 Inspection
 Palpation
 Percussion
 Auscultation
The subject should be examined in the Standing or Sitting
position in an erect, and in goodlight.

INSPECTION
 Inspection for Position of trachea
 Inspection for Symmetry of Chest
 Inspection for Chest wall abnormalities
 Inspection for Movement of the Chest
 Inspection for Apex beat
 Inspection for Dilated and engorged veins
 Inspection for Surgical or any Scars or Sinuses

INSPECTION FOR MOVEMENT OF THE CHEST
It is described in terms of rate, rhythm, equality and type.
Breathing Rate
•The normal respiratory rate in relaxed adults
is 14-18 breaths per minute
•The type of breathing in women is thoraco-
abdominal and in men is abdomino-thoracic
• The ratio of pulse rate to respiratory rate is 4 : 1.

PALPATION
 Palpation for Apex Beat (Position and Character)
 Palpation for Position of trachea
 Palpation for Measurement of the Chest Expansion
 Palpation for Assessing of Chest Expansion
 Palpation for Vocal fremitus (VF)
 Palpation for Direction of flow in veins
 Palpation for Tender points

TENDERNESS OVER THE CHEST WALL
It may be due to:
1.Empyema
2.Local inflammation of parietal pleura, soft tissue and
osteomyelitis
3. Infiltration with tumor
4.Non-respiratory cause (amoebic liver abscess).

PERCUSSION
 Percussion for the Lung fields

AUSCULTATION
 Auscultation for Breath Sounds
 Auscultation for Vocal Resonance
Listen:
■ anteriorly from above t h e clavicle down to t h e sixth rib
■ laterally from t h e axilla to t h e eighth rib
■ posteriorly down to t h e level of t h e 11th rib.
■ Assess t h e quality a n d amplitude of t h e b r e a t h
sounds. Identify any gap between inspiration a n d
expiration, a n d listen for added sounds.

ABNORMAL BREATH SOUNDS
• Normal, unobstructed airflow is relatively quiet, a smooth “whooshing” sound heard in the
earpiece. The presence of this quiet whooshing sound is indicative of a patent airway.
• Silence in the earpiece, on the other hand, is ominous and must trigger an immediate
response. Respiratory obstruction (in the presence of exaggerated ventilatory movements)
or respiratory arrest (no chest movements) may have developed and must be corrected
immediately, or it may merely be that the stethoscope has become disconnected from the
patient.
• Wheezing indicates partial obstruction in the lower airways (i.e., bronchioles) and is termed
termed bronchospasm.

• Snoring or the sound of fluid (a gurgling sound) indicates the presence of partial
obstruction of the upper airway. Snoring most often results when the base of the
tongue falls against the posterior wall of the pharynx, whereas the bubbling, gurgling,
or crackling sound of fluid indicates the presence of a liquid (i.e., blood, saliva, water,
or vomitus) in the airway.

MENTAL STATE
Appearance and Behavior
Emotional state
Delusions and Hallucination
Orientation in Place and Time
Level Of Consciousness
Intelligence

EMOTIONAL STATE
 Mood : facial expression (reflective of depression, mania, anxiety, schizophrenia)
Sleep and dreams : insomnia , sleep disturbing dreams

ORIENTATION IN PLACE & TIME
DISORIENTATION :
• Organic Brain Disease
• Schizophrenics
• Hysterical states

LEVEL OF CONSCIOUSNESS
Stupor - Patient shows some response, eg. to painful stimuli
Coma - makes no psychologically meaningful response to external
stimulus or to internal need

medical status mortality
ASA I Normal healthy patient without organic, biochemical, or psychiatric
disease
0.06-0.08%
ASA II Mild systemic disease with no significant impact on daily activity
e.g. mild diabetes, controlled hypertension, obesity .
Unlikely to have an
impact
0.27-0.4%
ASA III Severe systemic disease that limits activity e.g. angina, COPD, prior
myocardial infarction
Probable impact
1.8-4.3%
ASA IV An incapacitating disease that is a constant threat to life e.g. CHF,
unstable angina, renal failure ,acute MI, respiratory failure requiring
mechanical ventilation
Major impact
7.8-23%
ASA V Moribund patient not expected to survive 24 hours e.g. ruptured
aneurysm
9.4-51%
ASA VI – A declared brain dead patient whose organs are being removed for donor purposes.
(last approved by ASA house of delegates on October 15, 2014)

GOLDMAN RISK ASSESMENT SCALE
(1977)Factors Value
History Age > 70 years (5 point)
Myocardial infection with in 6 month (10 points)
Cardiac Exam Signs of CHF: ventricular gallop or JVD (11 points)
Significant aortic stenosis (3 points)
Electrocardiogram Arrhythmia other than sinus or premature atrial contractions (7 points)
5 or more PVC's per minute (7 points)
General Medical
Conditions
PO2 < 60; PCO2 > 50; K < 3; HCO3 < 20; BUN > 50; Creat > 3; elevated SGOT;
chronic liver disease; bedridden (3 points)
Operation Emergency (4 points)
Intraperitoneal, intrathoracic or aortic (3 points)
0-5 Points: Class I 1% Complications
6-12 Points: Class II 7% Complications
13-25 Points: Class III 14% Complications
26-53 Points: Class IV 78% Complications

• A chest x-ray, electrocardiogram
and blood chemistry (glucose, blood
urea nitrogen and electrolytes) are
indicated in patient with symptoms or
signs of pulmonary or cardiac disease
or a history of diabetes, hepatic or
renal disease.
• Patients with a history of a bleeding
disorder should have tests for
estimation of bleeding time,
prothrombin time and partial
thromboplastin time.
LABORATORY INVESTIGATIONS

INCLUDES-
• Patient’s counselling or psychological preparation
• Premedication
• Preoperative instructions
- Fasting instructions
- current or pre-existing drug therapy.
PREOPERATIVE PREPERATION

• Patient’s counselling or psychological preparation
Anticipated surgical events, risks and limitations,
benefits and alternatives of anaesthetic procedure
be discussed with the patient and his relatives.

• Written, informed, valid consent for anesthesia as well as
for surgery to be obtained prior to procedure.
• Also, special consent for medical problems due to medical
diseases and for tracheostomy, if difficult intubation or
airway is suspected.
• An adult who is mentally stable, well-oriented, not under
influence of drugs or alcohol - can sign the consent form
himself.
• Mentally subnormal individuals – Parents / guardians
• Minor patients – parents / guardians
• Orphanage patients - chief
INFORMED CONSENT

• CONSENT

OBJECTIVES OF PREMEDICATIONS – 10 A’s
• Anxiolysis - Relief of apprehension or anxiety / sedation
• Analgesia – smooth induction of GA
• Amnesia of perioperative events – Anterograde amnesia
• Antiemetic effect - Prevention of nausea and vomiting
• Antisialagogue effect – Reduction of salivary & bronchial secretion
• Antacid usage – Reduction of stomach acidity & volume
• Antiautonomic parasympathetic / sympathetic reflexes care -
actions
• Anaesthetic induction – Smooth facilitation
• Prophylaxis against Allergies
• Antibiotic regimen – Prophylactic / Specific
PREANESTHETIC MEDICATION

Provide relief from apprehension & anxiety, Peri-operative amnesia
BENZODIAZEPINE
anxiolytics but no analgesia
MIDAZOLAM
I
h
v
r
– 0.05-0.1 mg/kg (2 to 5 mg in 0.5 mg increment) – return to normal
within 4
Intra-nasal dose – 0.6 mg/kg
 DIAZEPAM
Gold standard
Oral doses – 0.2 - 0.5 mg / kg
Intravenous – 0.04 – 0.1 mg/kg
With opioid can produce respiratory and cardiovascular depression
FLUMEZANIL
Drug antagonized the sedative and amnestic effect of midazolam
0.1 -0.5 mg
Short acting – preferably given in infusion form

SEDATIVES-HYPNOTICS
Barbiturates
Priorly used but now generally no use
Replaced by benzodiazepine
Doses – 50-200 mg orally
Action within 15 to 20 minute – duration last – 2 to 4 hr
Butyrophenon
Mainly antiemetic but can produce sedation
Doses – IV/IM – 2.5 to 7.5 mg
Phenothiazine
Sedation, anticholinergic and antiemetic effect
Always used with opioids
Lytic cocktail – 50 mg pethidine + 25 mg promethazine + 10 mg chlorpromazine
 Promethazine
Antisialogogue + antihistaminic + Antiemetic + sedative
Doses – Orally – 10 – 25 mg
 Trimeperezine tartrate
Doses – 3-4 mg/kg – 2 hr preoperatively

ANALGESIC AGENT
Ketamine –
 Potent IV induction agent
 Posses analgesic property
 Major disadvantages –
• Increased salivation
• Emergence delirium (More common in adults & childrens)
 Very popular for premedication in children
 Combined with vagolytic agent to combat with the increased secreations
 Dose –
• Oral : 8 – 10 mg/kg
• IM : 4 – 5 mg/kg
• IV : 0.5 – 1 mg/kg

ANALGESIC AGENT
Morphine
Well absorbed after IM injection
Onset – 15 to 30 minute
Peak effect – 45 to 90 minute
Lasting for 4 hr
May cause – orthostatic hypotension, respiratory distress, addiction
Fentanyl (preferred most now a days/ given just before induction)
50 to 125 times potent than morphine
Respiratory depression is high
Dose – 1-2ugm/kg
Onset – 30 to 60 second
Route – intranasally, orally, transdermally
 Reversal agent - Naloxone
Pethidine
Doses – 50 to 100 mg – IM / IV – single dose lasts for 2 to 4 hour
Buprenorphine
Highly potent drug
3 to 6 umg/kg – IM/IV
Respiratory depression

ANTICHOLINERGIC AGENTS
Actions
Vagolytic
Increase heart rate by blocking acetylcholine on muscarinic receptor in SA node
Atropine is more effective than glycopyrolate / scopolamine
Useful in preventing intraoperative bradycardia resulting from vagal stimulation or carotid
sinus stimulation
Atropine (0.5mg IM) also helps in preventing vasovagal attack
Antisialogogue
 Induce drying of salivary, gastric, tracheobronchial and sweat gland secretion
 Glycopyrolate (0.1-0.3 mg IM) is more potent – long acting drying effect
 Should be given 30 minute prior to the procedure
Sedation and amnetia
Atropine and scopolamine cross blood-brain barrier
Atropine cause delirium in elderly
Scopolamine has good sedative and amnesic effect
 Side Effects
 Pupillary dilatation
 Tachycardia, cardiac arrhythmia
 Delirium, confusion, restlessness
 Increase body temperature

ANTIEMETICS-
- Metoclopramide (10mg i.m.) used as antiemetic & as prokinetic gastric emptying agent
prior to emergency surgery – 30-60 minute prior to surgery
- Domperidone (10mg oral) more preferred (does not produce extrapyramidal side effects)
- Ondansetron (4-8mg i.v.), a 5HT3 receptor antagonist, found effective in preventing post-
anaesthetic nausea & vomiting
DRUGS REDUCING ACID SECRETION -
-Ranitidine (150-300mg oral) or Famotidine (20-40mg oral) given night before & in morning along with
Metoclopramide reduces risk of gastric regurgitation & aspiration pneumonia
-Proton pump inhibitors like Omeprazole (20mg) with Domperidone (10mg) is preferred nowadays

PREMEDICATION USED IN OUR UNIT
1. Tab. Diazepam 0.25 mg orally
2. Tab. Pantoprazole 40 mg orally
3. Syp. Cremaffin orally
4. Inj. Ondensetron 8 mg IV – 1 hour prior to surgery
Night before surgery / 8 – 10 hours prior to surgery

CONCURRENT DRUG THERAPY
To be continued To be modified To be discontinued
Antiarrythmics Insulin Diuretic- on the day of surgery
Antiasthmatic Oral-anticoagulant Oral hypoglycemic
Antibiotics Steroid cover Aspirin – 1 wk prior
Antiepileptic Mono Amine Inhibitor – 2 wk prior to
surgery
B-blocker Oral contraceptive – 1 mnth cycle
Cachannelblocker
Eye drops
Sedative/anxiolytic
immunosuppressant

• Fasting Guidelines
AGE CLEAR FLUIDS NON-CL EAR
FL UIDS/SOL IDS
Child< 6 months 2 hr prior 4-6 hr prior
Child-6-36 months 2-3 hr prior 6 hr prior
Child> 36 months 2-3 hr prior 6 hr prior
Adults 2-3 hr prior 6 hr prior/
overnight

• PRE OPERATIVE ORDERS

1. SMOKING –
• Ideally should be stopped 4 to 6 weeks prior to the surgery to decrease the incidence
of postoperative pulmonary complications.
• Stopping 1 to 2 weeks before the surgery - benefits the patient by enhancing the
ciliary activity of respiratory mucosa and by reduction in the sputum volume.
• Nicotine - causes tachycardia and peripheral vasoconstriction.
• With high levels of carbon monoxide in blood - patients are susceptible for hypoxic
episodes.
OTHER INSTRUCTIONS

2. DENTURES –
• Chances of aspiration of loose dentures or slipping from the position - can cause
obstruction of the airway.
3. ARTIFICIAL LIMBS –
• Should be removed as metal component of the artificial limb may induce electrical
burns.
4. ARTIFICIAL EYES AND CONTACT LENSES –
• Dislodgements can cause corneal abrasions or injury to surrounding delicate
of eye.

• Anesthesia machine is an equipment, by which the
operator can deliver a desired concentration of a
mixture of anesthetic agents (gases as well as
liquids) in an inhalational (gaseous) form with
oxygen and/or air, which serves as a vehicle to
this mixture to the outlet of the equipment.
ANESTHETIC EQUIPMENTS
ANESTHESIA MACHINE

• Anesthesia machines can be of either intermittent flow or continuous
flow variety.
• Intermittent flow machines (e.g. Walton 5 machine) - there is a demand
valve, i.e. gases flow only on demand of the patient.
• In continuous flow machines (e.g. Boyle machine), oxygen, nitrous oxide,
air, etc. have individual flow meters for setting desired flow of each gas.

• Vaporizers - for setting desired percentage output concentration of the liquid
anesthetic agents like halothane, isoflurane, etc.
• Flow meters for gases and vaporizers for liquid anesthetic agents are gas/agent
specific and the one meant for a particular gas or anesthetic agent cannot be used for
the other.
• Most dangerous hazard - is the delivery of a hypoxic gas mixture
• This can lead to hypoxic brain damage and coma, even cardiac arrest and death can
occur.
• To avoid this hazard - newer anesthesia machines have devices, which in the event of
delivery of a hypoxic gas mixture activate an alarm either auditory or visual, which tells
the operator that a hypoxic gas mixture is being delivered, so that immediate action
can be taken

• Breathing system is an assembly of equipment, that not only carries anesthetic mixture
from the outlet of anesthesia machine to the patient, but also allows to monitor and
control patient’s breathing.
• COMPONENTS –
Bag mount with a reservoir bag (1.5 to 2 liter Capacity)
Long (one meter) corrugated rubber or plastic tubing/s (breathing tube/s)
An expiratory valve - Ordinary spring loaded/nonrebreathing valve, which is connected
to a mask or an endotracheal tube attached to the patient.
BREATHING SYSTEM (CIRCUIT)

• Breathing system can be reusable or disposable.
• 3 TYPES –
Single simple corrugated tubing (e.g. Magill’s system)
Coaxial tubings, i.E. One tubing within the other (e.g. Bain’s system)
Double tubings, inspiratory and expiratory (e.g. Closed circuit).

• Mask is an integral part of any anesthetic
breathing system/circuit during the
induction phase (beginning) of anesthesia
or any resuscitation procedure.
• Allows administration of gases from the
breathing system, without introducing any
invasive apparatus (e.g. endotracheal tube)
into the patient‘s airway.
• Placed on the patient’s face covering
his/her mouth and nose (face-mask) or only
on the nose (nasal-mask).
ANESTHETIC MASK

• Parts:
Connector or mount – in which breathing system
attached; can be made of hard rubber, plastic /
metal
Body – made up of rubber, neoprene, plastic /
silicon
Edge or seal – Part of mask that comes in contact
with the face; anatomically shaped
• Sizes: 1, 2, 3, 4, 5.
• Body of the mask - made up of rubber, neoprine,
plastic or silicone.

Laryngoscope is designed for doing
direct laryngoscope (directly viewing
the vocal cords) and to pass an
endotracheal tube into the larynx
under vision.
• Parts: Handle, blade with light bulb.
• Sizes (for the blades): Neonate
(infant), pediatric (child), adult and
extra large.
LARYNGOSCOPE

Laryngoscope blades can be -
• Curved (e.g. MacIntosh
Laryngoscope—most
popular)
• Straight (e.g. Miller
Laryngoscope—useful for
neonates and small children)

• PARTS OF BLADE –
Base
Tongue plate
Flange
Web
Tip
Bulb socket

• The base is slotted to engage the hinge pin of
the handle.
• The tongue blade or spatula serves to
manipulate the tongue and other soft tissues to
visualize the larynx.
• The flange is parallel to the tongue plate and
connected by a web. It helps to deflect the
interfering soft tissues and to guide the
endotracheal tube.

• The tip of the blade is blunt and thick to prevent trauma to the soft tissues. It elevates
and secures the epiglottis directly (with straight blade) or indirectly (with curved
• The bulb socket is meant for fitting the light bulb. It has an electrical connection to
the hook on the base. As the blade is locked on the handle (at 90 degrees), electrical
connection is made complete and the bulb is illuminated.

ENDOTRACHEAL TUBE
• Endotracheal tube is a specially designed
tube with one end straight and the other
being obliquely cut (bevelled end).
• Beveled end enters the trachea through the
laryngeal inlet
• It is always passed with direct laryngoscopy
under vision after anesthetizing the patient,
except in cases, where patients are unable to
open mouth, e.g. temporomandibular (TM)
joint ankylosis or when a difficult intubation
is expected.
• Sizes: 2, 2.5, 3, 3.5, 4,……10, 10.5 (internal
diameter in mm).

TYPES -
• Can be plain or cuffed.
• Can be made up of plastic (generally PVC), red rubber or latex.
• Disposable or reusable.
• Low volume-high pressure or high volume-low pressure types.
• May be introduced orally or nasally

TECHNIQUES OF INTUBATION
• OROTRACHEAL INTUBATION
• ENDOTRACHEAL INTUBATION
• FIBEROPTIC INTUBATION

OROTRACHEAL
INTUBATION
1. The laryngoscope is held in the left
hand.
2. With the patient’s mouth opened the
blade is introduced into the right side of
the oropharynx—with care to avoid the
teeth.
3. The tongue is swept to the left and up
into the floor of the pharynx by the blade’s
flange.
4. The tip of a curved blade is usually
inserted into the vallecula, and the straight
blade tip covers the epiglottis.
5. With either blade, the handle is raised
up and away from the patient in a plane
perpendicular to the patient’s mandible to

6. The “backward, upward,
rightward, pressure” (BURP)
maneuver applied externally
moves an anteriorly positioned
glottis posterior to facilitate
visualization of the glottis.
7. The cuff is infl ated with the
least amount of air necessary to
create a seal during positive-
pressure ventilation

Sites for auscultation
of breath sounds at
the apices and over
the stomach.

N A S OT R AC H E A L
I N T U B AT I O N
1. A TT lubricated with water-
soluble jelly is introduced along
the floor of the nose, below the
inferior turbinate, at an angle
perpendicular to the face .
2. The tube’s bevel should be
directed laterally away from the
turbinates.
3. The tube is gradually
advanced, until its tip can be
visualized in the oropharynx.

F I B E R O P T I C
I N T U B AT I O N
FOI is ideal for :
• A small mouth opening
• Minimizing cervical spine
movement in trauma or
rheumatoid arthritis
• Upper airway obstruction,
such as angioedema or tumor
mass
• Facial deformities, facial
trauma

BOUGIE
• The bougie (also called 'introducer', 'gum-elastic
bougie' or 'GEB') is device which allows
a Seldinger-like technique of intubating a
airway. This means the device is inserted into the
airway first, then an endotracheal tube is
railroaded over the bougie into the airway, after
which the device is removed.
• The device is moderately flexible and can be bent
into shape from its straight form, in which it is
supplied
ANESTHETIC EQUIPMENTS
ADJUNCTS TO INTUBATION

LIGHTED STYLET
Lighted stylet guided intubation can be a
useful technique for oral and nasal
intubations in both asleep and awake
patients.
It can be used in anticipated and
unexpected difficult airways where
conventional direct laryngoscopy has
failed.
Manipulation of the head and neck can
be kept minimal and the patient does
require a wide mouth opening (6-8 mm)

O R O P H A R Y N G E A L
A I R WAY
An oropharyngeal airway (also known as
an oral airway, OPA or Guedel pattern
airway) is a medical device called an airway
adjunct used to maintain or open a patient's
airway.
• Parts: Flange, bite portion, air/suction
channel
(curved portion)
• Sizes: 00,0,1, 2, 3, 4,5,6
It does this by preventing the tongue from
covering the epiglottis, which could prevent
the person from breathing.
When a person becomes unconscious, the
muscles in their jaw relax and allow the
tongue to obstruct the airway

I N S E R T I N G
O R O P H A R Y N G E A L
A I R WAY

N A S O P H A R Y N G E A L
A I R WAY
The NPA provides a passage of airflow
between the nares and pharynx and can
be used in patients who are conscious or
semiconscious with intact gag reflex.
• Parts: Flange or a movable disc
attached to a tube
• Sizes (diameter)
– 7.0/7.5 for adult males
– 6.5/7.0 for adult females
– Same/one size smaller than an
appropriate
endotracheal tube for children.

L A R Y N G E A L M A S K
A I R WAY ( L M A )
Laryngeal mask airway (LMA) is a device
which is midway between mask and
endotracheal tube. Just as mask makes an
airtight seal around the face, LMA makes an
airtight low-pressure seal around laryngeal
inlet after inflation of the cuff.
• Parts: Mask, tube at an angle of 30
degrees, black line on tube to face upper
incisors and pilot balloon.
• Versions: Plain, reinforced, and intubating,
pre-sale LMA.
• Sizes: 1, 1.5, 2, 2.5, 3, 4, 5.

MAGILLS
FORCEPS
An instrument, which is most often used
for guiding an endotracheal tube, from
the pharynx into the larynx during nasal
intubation.
It is also used to pack the throat with a
roller gauze during oral and pharyngeal
surgery, to pick up a broken or
dislodged tooth lying in the oral cavity
or to pass a Ryles (nasogastric) tube. It is
L-shaped and it has no catch.
It is available in three sizes—infant, child
& adult.

R E S U S C I TAT I O N
B AG
Resuscitation bag is an assembly of
equipment consisting of a self-
inflating bag, a non-rebreathing
valve and a facemask
• Sizes: Three sizes are available; for
infant, child and adult.

M E T H O D O F U S I N G
• After proper positioning of the
patient, the mask has to be
placed on the patient’s face and
the bag can be intermittently
compressed and released while
watching the inflation and
deflation of the patient’s chest.
• The exhalation blast can be
heard or felt from the expiratory
port of the nonrebreathing valve.

B LO O D P R E S S U R E
M O N I TO R
Blood pressure monitor is available in various
forms:
• Simple sphygmomanometer/aneroid dial
• Noninvasive automatic blood pressure monitor
(NIBP)
• Invasive direct arterial blood pressure monitor
(IABP)
Blood pressure is generally monitored on the
right or left upper arm. It is necessary to
monitor patient’s blood pressure as most of the
anesthetic agents are vasodilators and/or
myocardial depressants, giving rise to
hypotension.
MONITORING EQUIPMENTS

C A R D I O S CO P E
Cardioscope not only allows to monitor
the electrocardiogram (ECG) of the
patient, but it also allows to monitor
patient’s heart rate, rhythm, the type of
arrhythmias and ST-segment changes
(important to diagnose myocardial
ischemia).
It has minimum three leads and maximum
12 leads. Generally, a three lead ECG is
monitored under anesthesia.
These leads are attached on the anterior
chest wall, one near the right shoulder,
one near the left shoulder and one near
the lower end of sternum on the right

P U L S E OX I M E T E R
Noninvasive equipment that allows to
monitor continuously the oxygen
saturation of the patient and also the
heart rate.
It has a small probe which can be
attached on any of the fingers or toes
or on the ear lobule.

C A P N O G R A P H
An equipment that continuously
records the carbon dioxide tension
(in mm Hg or %) of the expired gas
mixture.
It is popularly known as an End Tidal
CO2 monitor (ETCO2).
It is a noninvasive monitor having a
probe or an adapter that can be
attached to an endotracheal tube, a
face-mask or a nasal catheter.

OXYGEN CYLINDER
Oxygen cylinders are available in various
sizes.
They are black in color with a shoulder
painted white.
Those meant to be used on anesthesia
machines have a flushed valve whereas
those used in the wards have a bull-nose
valve.
It is not possible to use a flushed valve
cylinder in the wards.
On the ward cylinder, oxygen flowmeter
can be attached and there is also a facility
to attach a humidifier to the flowmeter.

OX YGEN F LO WMETER
Oxygen flowmeter allows the operator to
deliver a desired flow of oxygen to the patient.
Generally, 3 to 4 liters per minute of flow is
given, but it varies from patient to patient,
depending upon the type of oxygen delivery
system , type of surgery done, age of the
patient and general condition of the patient.

OXYGEN MASK
Polymask is a semioval-shaped mask,
available in two sizes, for children
and for adults. It is a loosely fitting
mask around the mouth and nose
through which moderate flow of
oxygen (3 to 6 liters) can be
delivered.
Recommended flow rate is 10 to 15
liters/min of oxygen

NASAL PRONGS
Nasal prongs are the most simplest,
most commonly used and easily
available devices.
But, not more than 1 to 3 liters of
oxygen per minute can be
delivered, as high flow makes the
patient uncomfortable due to
wheezing sound and a feeling of
dry mouth.
Generally with oxygen flow rate of 1
to 2 liters/ min, these devices
provide 24 to 28 percent oxygen.

PHARMACOLOGY
OF
GENERAL
ANESTHETICS

INTRAVENOUS
1. BARBITURATES
- Thiopental
2.BENZODIAZEPINES
-Diazepam
- Midazolam
3..OPIOIDS
- Fentanyl
4. DISSOCIATIVE
- Ketamine
5. MISCELLANEOUS
- Etomidate
- Propofol
ANESTHETICS
INHALATIONAL
1. GASES
- Nitrous oxide
2. VOLATILE LIQUIDS
- Ether
- Halothane
- Isoflurane
- Desflurane
- Sevoflurane
PHARMACOLOGY OF GENERAL ANESTHETICS

IDEAL PROPERTIES
• Pleasant odour,non irritant to respiratory tract ,pleasant and rapid induction of
• Posses low blood/ gas solubility.
• Chemically stable
• Neither inflammable nor explosive.
• Capable of producing unconciousness with analgesia and some degree of muscle
relaxation.
INHALATIONAL ANESTHETICS

• It should not be metabolized in the body, non toxic and not provoke allergic
reactions.
• Minimal depression of CVS and RS .
• Easy to administer.
• Should be completely inert and eliminated completely and rapidly via lungs.

The important characteristics of Inhalational anesthetics which govern the anesthesia
are
• Solubility in the blood
(blood : gas partition co-efficient)
• Solubility in the fat
(oil : gas partition co-efficient)

SOLUBILITY IN THE BLOOD
(blood : gas partition co-efficient)
It determines the rate of induction and recovery of
Inhalational anesthetics.
• Lower the blood : gas co-efficient –
faster the induction and recovery – Nitrous oxide.
• Higher the blood : gas co-efficient –
slower induction and recovery – Halothane.
Louis, Missouri. 2009;Chapter 5: anesthesia concept and techniques;p.67-76

SOLUBILITY IN THE FAT
(oil : gas partition co-efficient)
• It is a measure of lipid solubility.
• Lipid solubility - correlates strongly with the potency of the anesthetic.
• Higher the lipid solubility – potent anesthetic. e.g., halothane

MAC value
• Measure of inhalational anesthetic potency.
• It is defined as the minimum alveolar anesthetic concentration ( % of
the inspired air) at which 50% of patients do not respond to a surgical
stimulus.
• Greater the MAC lower the anesthetic potency.

OIL GAS PARTITION CO-
EFFICIENT

Inhalation
Anesthetic
MAC value % Oil: Gas
partition
Nitrous oxide >100 1.4
Desflurane 7.2 23
Sevoflurane 2.5 53
Isoflurane 1.3 91
Halothane 0.8 220

• Prepared by Priestley in 1772
• Anesthetic properties described by Sir Davy in 1799
• Colorless, odorless, tasteless, and is nonflammable
• Weak anesthetic, powerful analgesic
• No muscle relaxation
NITROUS OXIDE

• MAC value is 105%(needs other agents for surgical anesthesia)
• Minimal effects on heart rate and blood pressure.
• Respiration- Decreases tidal volume.
• Post operative nausea and vomiting
• Avoided in 1st trimester
NITROUS OXIDE

• The second-gas effect
The ability of the large volume uptake of one gas (first gas) to
the rate of rise of the alveolar partial pressure of a concurrently
administered companion gas (second gas) is known as the second gas
effect.
Ex-Halothane (1%) & N20:O2 ( 75%: 25%)
NITROUS OXIDE

Diffusion Hypoxia
• N2O has low blood solubility, rapidly diffuses into alveoli and dilutes
alveolar air- PP of oxygen in alveoli is reduced, resulting in hypoxia
called as diffusion hypoxia.
• Prevented by giving 100% oxygen for few mins, after discontinuing
NITROUS OXIDE

• 2-bromo-2-chloro-1,1,1-trifloroethane
• Non flammable,non explosive.
• Pleasant smell, non irritating.
• BP falls in proportion to the vapour inhaled.
• Depression of respiratory centre.
• Respiratory rate increases, depth of respiration decreases.
HALOTHANE (FLUTHANE)

• Mild relaxation of skeletal muscle.
• Pharyngeal and Laryngeal reflexes are
abolished,coughing is suppressed.
• Urine formation is decreased due to low GFR
• Less post operative nausea and vomiting.
• About 20% is metabolized in liver, rest is exhaled
out.
• Malignant Hyperthermia can occur in
individuals.
HALOTHANE (FLUTHANE)

• Synthesized in 1965 by terrell, introduced into
practice in 1984
• Cheap and widely used
• Highest oil gas partition cofficient (90.8)
• Non carcinogenic,nonflammable,pungent
• Less soluble than halothane.
• It can cause coronary artery vasodilatation
• Depresses respiratory drive and ventilatory
responses
• Myocardial depressant-less than halothane
ISOFLURANE (SOFANE)

• Excellent muscle relaxant-- potentiates effects of
neuromuscular blockers.
• Induction by 3 to 4 % isoflurane in air or in
oxygen, or by 1.5 to 3 % isoflurane in 65 % nitrous
oxide.
• Maintenance by 1 to 2.5 % isoflurane.
• Bronchoirritating, laryngospasm
• Pungent smell – not good induction agent
ISOFLURANE (SOFANE)

• Volatile anesthetic is a nonflammable
fluorinated varient of Isoflurane
• Lowest oil-gas coefficient (18.7)
• Very fast action (on and off) makes it a great
choice for outpatient anesthesia.
• Induction by using 6 to 10 % desflurane in air or
in oxygen, or by using 5 to 8 % desflurane in 65
% nitrous oxide
• Maintenance with 5 to 7 % desflurane
DESFLURANE

• As higher conc. are used, may irritate air
passage,
and induce coughing.
• Pungent smell-not suitable for induction.
• Degree of respiratory depression and fall in B.P,
similar to isoflurane.
• Exhaled unchanged and more rapidly.
DESFLURANE

• SEVOFLURANE
• Nonflammable fluorinated isopropyl ether.
• Properties intermediate between isoflurane and
desflurane.
• Induction and emergence from anesthesia are
fast.
• Absence of pungency makes it pleasant and
administrable through face mask.
• It does not sensitize the heart to arrhythmias or
cause coronary artery steal syndrome.
SEVOFLURANE

• Does not irritate the airway. Has low solubility in blood
,so used for rapid induction without intravenous
anesthetics
• Induction by using 1.5 to 3 % sevoflurane in air or in
oxygen, or by using 0.7 to 2 % sevoflurane in 65 %
nitrous oxide.
• Maintenance with 0.4 to 2 % sevoflurane.
• Expensive
SEVOFLURANE

CLINICAL
SIDE EFFECTS OF
INHALED
ANESTHETICS

• Used as inducing agent.
• Poor analgesic and muscle relaxant
properties.
• Suppresses excitatory neurotransmitter
(acetylcholine) and enhance inhibitory
neurotransmitter (GABA).
• pH>10, water soluble.
• Unstable, freshly prepared.
• Rapid onset 30-60sec.
INTRAVENOUS ANESTHETICS
THIOPENTAL

• Elimination half life-3-12 hours.
• Dose- 3-5mg/kg. IV
• Decreases blood pressure due to vasodialation.
• Respiratory depression, can lead to bronchospasm.
• Occasionally used for rapid control of convulsions. Dose-
dependent suppression of CNS activity
• Contraindications : porphyria , status asthematicus.
THIOPENTAL

• Produce sedation and amnesia
• Potentiate GABA receptors.
• Onset of action is 30-60 secs.
• Duration of action 50-80mins.
• Dose- Premedication-0.04-0.08mg/kg
• Induction- 0.1-0.3mg/kg IV.
BENZODIAZAPENES

• Minimal depression of cardiac and respiratory system.
• Decreases intra cranial pressure, causes anterograde amnesia.
• Dependence- onset of physical or psychological symptoms after
reduction of dose.
• Overdose- treared by giving Flumazenil – 0.01mg/kg upto 0.2mg . IV
BENZODIAZAPENES

• Short acting Opioid.(30-50mins)
• Potent anlgesic.
• Minimal cardiac effects-- no myocardial depression
• Marked respiratory depression.
• Tone of chest muscles may increase after rapid
fentanyl injection,muscle relaxant is required.
FENTANYL

• Dose-2-4μg/kg
• Repeated dose may be required every 30 mins.
• Side effects nausea, chest wall rigidity, seizures,
constipation, urinary retention
FENTANYL

• Dissociative amnesia
• Profound amnesia/ analgesia despite maintaining
counsciousness and protective reflexes.
• Exitation of inhibitory neurotransmitters
• Dose- Analgesia-0.1-0.5mg/kg IV
- Induction- 4-8mg/kg
• Mixed with propofol infusion - 1mg ketamine per
10mg propofol
KETAMINE

• Increases heart rate, cardiac output,
BP.
• Potent bronchodialator
• Increases salivation.
• Decreases cerebral blood flow and
intracranial pressure
• Hallucinations and nightmares.
KETAMINE

• Excitation of inhibitory neurotransmitters
• Oily liquid employed as a 1% emulsion for IV induction
• Available in 20 ml vials
• Rapid onset and short duration of action
• Induction dose: 1-2.5mg/kg
• Sedation dose: 0.2mg/kg
• Decreases systemic vascular resistance.
PROPOFOL

• Profound depression of upper
airway reflexes.
• Anti emetic.
• Anti epileptic.
• Adverse effect- burning on injection
- hypersensitivity reaction.
PROPOFOL

• Direct CNS depressant (thiopental) and GABA agonist
• Lipid soluble. Pain on injection.
• Dose- 0.2-0.3mg/kg
• Minimal cardiac and respiratory effect.
• Anti epileptic
• Post op nausea and vomiting.
ETOMIDATE

Muscle
Relaxant
NONDEPOLARIZING
1. Long acting
-pancuronium
- tubocurarine
2.Intermediate acting
- vecuronium
3.Short acting
- mivacurium
DEPOLARIZING
- Succinylcholine
- Decamethonium
MUSCLE RELAXANTS

• Initially nitrous oxide 70% in oxygen is used
• Anaesthesia is deepened by the gradual introduction of
increments of a volatile agent e.g sevoflurane.
• Maintenance concentrations of isoflurane (1-2 %)or
sevoflurane(2-3%).
• If spontaneous ventilation is to be maintained throught
the procedure,the mask is applied more firmly as
conciousness is lost and airway is supported manually
• Pre- oxygenation may be started with 100% oxygen
using face mask. At the rate of 8L-10L/min
INDUCTION

AGENT INDUCTION DOSE
thiopental 3-5 mg/kg
etomidate 0.3mg/kg
propofol 1.5mg/kg
ketamine 2mg/kg
INDUCTION

• Inhalational agents
• Propofol infusion
• Oxygen + N2O
• Relaxants – VECURONIUM, ATRACURIUM, PANCURONIUM etc.
• Analgesia – opioids
• Sedation – midazolam etc.
MAINTAINENCE

• Check equipment
• Check drugs
• Turn off agents
• Give 100% oxygen
• Suction
• Reverse relaxant
• Usually a combination of neostigmine glycopyrolate in the ratio of 5:1, or
neostigmine and atropine in the ratio of 5:2 is given.
• Wait for adequate breathing
• Wait until patient wakes up
• Extubate and give 100% O 2 by mask
REVERSAL

• Shifted to recovery for Post operative care
• N. P. O FOR 4-6 hrs.
• Vitals monitoring should be done.
• IV fluids and blood products if required
• Analgesia- IV or IM NSAIDs or opioids
• Antiemetics
• Antibiotics
• Continue medications for medical disorders
POSTOPERATIVE CARE

• Patient experiencing hypoventilation can develop hypoxemia, oxygen deficiency in arterial
blood, or hypoxia, impaired tissue oxygenation.
• CAUSES –
 Fluid overload or pulmonary embolism
 Cardiac arrest,
 Atelectasis,
 Underlying respiratory illness such as asthma or COPD,
 Breathing machine error or a diffusion deficit
• MANAGEMENT -
Oxygenation of the patient is extremely important to raise the oxygenation levels to the
desired range.
HYPOVENTILATION

• The contents of the patient’s stomach rise up from the esophagus and end up in the
trachea as the patient is under heavy sedation and cannot control swallowing and coughing
him or herself. (Niemi-Murola 2014.)
• The consequences can be acute lung damage or pneumonia that can ultimately lead to
death of the patient.
• RISK FACTORS –
 Emergency surgery
 General anesthesia
 Inexperienced anesthetist and
 Patient dependent reasons such as lack of fasting, delayed gastric emptying or gastric
hyper secretion
PULMONARY ASPIRATION

• A bronchospasm is a reflex bronchiolar constriction that can be centrally mediated or a
local response to airway irritation.
• This constriction can be elicited by stimuli, such as secretions, blood, or foreign bodies.
• CLINICAL MANIFESTATIONS –
Expiratory wheezing
Increased airway resistance.
Tachypnea and dyspnea (consciously sedated patients)
BRONCHOSPASM

• MANAGEMENT –
Nonsedated or minimally sedated patients - to inhale a B agonist inhaler, such as
albuterol (4–8 puffs).
In moderately to deeply sedated patients, 100% oxygen with a full face mask should
immediately initiated.
If patients can be ventilated, nebulized albuterol (6–10 puffs) can be administered.
After the use of a B agonist, if the bronchospasm is still present, subcutaneous
epinephrine in doses of 0.3 to 0.5 mg of 1:1000 is used.
If after all the prior medications are administered and there is still difficulty ventilating
patients, intubation should be considered.

• A laryngospasm is a spasm of the intrinsic muscles of the larynx causing closure of the
airway at the level of the vocal cords.
• It is a protective reflex mechanism that prevents irritants, such as blood, saliva, or
irrigation, as well as solid materials from entering the lower airway.
• The classic sign - high-pitched stridor or crowing for a partial laryngospasm and
silence for a complete obstruction.
• CAUSES - local irritants and the depth of anesthesia
LARYNGOSPASM

• PREVENTION –
Proper airway maintenance.
Use of throat pack or partition to keep foreign material out of the airway.
Proper suctioning techniques aid in airway control.
Head positioning (sniffers position) will position the airway in a straight-line
physiologic position.

• MANAGEMENT –
Ventilation of patients with a full face mask and 100% oxygen.
If patients cannot be ventilated, a small dose of succinylcholine 0.15 to 0.30 mg/kg
intravenously (IV) in adults is used to break the spasm and initiate ventilation –
individuals
In larger individuals or a complete spasm, 0.3 to 0.6 mg/kg IV should be considered.
If the spasm continues, an intubating dose of succinylcholine 1 mg/kg should be
administered along with endotracheal intubation.

• The obstruction of the airway is usually located in the upper airway (supraglottic
region) and is caused by the loss of pharyngeal muscle tone.
• With the loss of muscle tone, the tongue is displaced posteriorly and occludes the
airway.
• CAUSES –
Deep anesthesia
Foreign bodies, such as teeth, aspirate, prosthetic devices, or surgical Instruments.
• CLINICAL MANIFESTATIONS –
Paradoxic breathing with sterna retraction and abdominal muscle activity.
AIRWAY OBSTRUCTION

• Hypotension develops as a result of peripheral venous pooling of blood.
• This condition causes a decrease in the preload, so BP decreases and cerebral blood
flow is decreased to the point of a loss of consciousness.
• Patients arriving in the office for anesthesia usually do not have preoperative
hypotension and tachycardia. Their anxiety is more likely to present as minor
elevations in BP as compared with their consultation BP along with tachycardia.
However, the combination of volume status from being NPO and anesthetic induction
medications can cause a hypotensive episode.
• Propofol and/or volatile anesthetic gases are known to decrease BP.
• Allergic reactions during anesthesia are another source of hypotension
• hypoxia and hypercarbia;
HYPOTENSION

MANAGEMENT -
• Before vasopressors are given, the depth of anesthesia should be reduced and a bolus
of IV fluid should be tried - up to 10 mL/kg
• If an allergic reaction is suspected –epinephrine (IM adult dose is 0.3 mg of 1:1000)
• Patients that present with hypotension and bradycardia (heart rate <60 beats per
minute) - anticholinergic agent like atropine (0.5 mg IV every 3 to 5 minutes up to a
maximum dose of 3.0 mg)
• Ephedrine (5 mg IV bolus every 5 to 10 minutes as needed).
• Phenylephrine 1% (100 mg in adults every 5-minute intervals)

• CAUSES OF INTRAOPERATIVE HTN –
Intubation and airway manipulation
Light anesthesia and pain
Exogenous epinephrine
Hypoxia and hypercarbia
Hypovolemia
Hypothermia
Volume overload and/or bladder distention
Holding perioperative antihypertensive medications
HYPERTENSION

• CAUSES -
Female gender
Obesity
Pregnancy
Abdominal distention
Premedications- opiods, NSAID’s
Anesthetics- ether, nitrous oxide.
Presence of pain,hypoxia,hypotention,hypogycimia in post op period
POSTOPERATIVE NAUSEA & VOMITING

MANAGEMENT -
Underlying cause
Supine position
Antiemetics-
Promethazine 12.5-25mg IM/IV(antihistaminic)
Metoclopramide 10-20 mg orally.
Ranitidiine 50 mg IV
Sodium citrate 30-60ml orally

• Hypermetabolic syndrome occurs in genetically susceptible patients when exposed to
anesthetic triggering agents.
• Triggering agents - Halothane, Isoflurane, Desflurane, Sevoflurane, Succinylcholine.
• The syndrome is thought to be due to reduction of reuptake of calcium ions by
sarcoplasmic reticulum leading to sustained muscle contraction.
• This results in signs of hypermetabolism like tachycardia, acidosis, hypercarbia,
hypoxemia and hyperthermia.
MALIGNANT HYPERTHERMIA

MANAGEMENT -
• Discontinue all anesthetic agents.
• Administer Dantrolene 2.5mg/kg IV. And repeat to a total of 10 mg/kg.
• Hyperkalemia to be corrected by Insulin and glucose
• Cold sponging
• Monitor urinary output

• Even a slight descend in core temperature of the body, has great effects on some
patients of certain risk groups.
• EFFECTS –
 Two- to three times more unwanted cardiac events,
 Doubling the amount of blood loss,
 Three times more likely to get a wound infection
 Lengthens the time of recovery from anesthesia and the operation
• General anesthesia itself can lower the core temperature of the patient even over one
Celsius.
• This is due to general anesthesia’s deactivation of the thermoregulation center of the
pituitary gland, which then results in core-to-peripheral redistribution of body heat.
HYPOTHERMIA

• The usage of muscle relaxants during the operation greatly affects the patient’s
muscles ability to shiver and produce heat, thus resulting in the temperature drop.
(Sessler 2008.)
• If the temperature is not controlled and managed during the operation it can result in
post-operative hypothermia.

CAUSES
• Occurs during light plane of
anesthesia
• Causes - Irritation due to artificial
airways,blood, regurgitated gastric
material.
MANAGEMENT
• Deepening of anesthesia
• Giving muscle relaxant
COUGHING

1 Reflex stimulation under light
anesthesia
- Tracheal/ surgical stimulation.
2. Endotracheal tubes- kinking,
overdistended, inserted too far
3. Anaphylactic reaction
4. Aspiration
5. Pnemothorax.
MANAGEMENT -
1.Rule out mechanical obstruction
2. Intermittent positive pressure ventilation
3.Deepen the level of anesthesia
4. Aminophylline IV 250-500mg slowly.
5.Salbutamol IV. 250 mg/2.5mg inhalation
6.Adrenaline IV (1-3ml of 1:10,000)
7 Steroids IV 200mg. 4 hourly.
WHEEZING
CAUSES -

CONCLUSION
Preparing a patient for anaesthesia requires an
understanding of the patient’s pre-operative status,
the nature of the surgery and the anaesthetic
techniques required for surgery, as well as the risks
that a particular patient may face during this time.
Patients often have comorbidities that require
careful assessment and co-ordination.

Pre-operative anaesthetic assessment services
decreases complication rates and mortality. The pre-
operative visit may relieve anxiety and answer
questions about both the anaesthetic and surgical
processes
Effective communication and a team approach are
vital in the pre-operative period.
CONCLUSION

Complications and malpractice lawsuits are often attributable to poor
preparation and failures in communication
Essential team members include anaesthetists, surgeons, physicians and
general practitioners.
Anaesthetic pre-operative assessment have been shown to be safe and
effective at pre-operative screening and should be an integral part of
the team
CONCLUSION

• T. Y. Euliano,J. S. Gravenstein, Essential Anesthesia -From Science to Practice:United States of
America by Cambridge University Press, New York;2004: Introduction A very short history of
anesthesia;p.1-4
• Anesthesia in outpatient facilities, Parameters of Care:Clinical Practice Guidelines for Oral and
Maxillofacial Surgery; J Oral Maxillofac Surg 70:e31-e49, 2012, Suppl 3
• Hugh C. Hemmings jr et al; emerging molecular mechanisms of General anesthetic action; TRENDS
in pharmacological sciences vol.26 no.10 october 2005
• Richard H. Haug, Henry H. Rowshan, Dale A. Baur; Atlas of the Oral & Maxillofacial Surg Clinics Of
North America: Management of Airway,vol 18 No.1, March 2010
• James Cphero et al,Adult Airway Evaluation in Oral Surgery, Anesthesia:Oral and Maxillofacial

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