General Anaesthesia Guide

GENERAL ANAESTHESIA
Presented by:
Dr. Sapna K Vadera
(P.G. Student)
Guided by:
Dr. S.R.Shenoi
(Prof, Guide and H.O.D)
Dept Of Oral And Maxillofacial surgery
VSPM’S Dental College, Nagpur

CONTENT
• Introduction
• History
• Levels of sedation
• Goals of sedation
• Sequence of depression of CNS
• Mechanism of action of GA
• Pre- anesthetic evaluation
• Pre-operative preparation

• Anaesthetic Equipments
• Pharmacology of anaesthetics
• Muscle relaxants
• Stages of anaesthesia
• Post operative care
• Complications of GA.
• Conclusion
CONTENT

INTRODUCTION
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Charles F. Cangemi, Jr, Administration of General Anesthesia for Outpatient Orthognathic Surgical
Procedures American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 69:798-807, 2011

HISTORY
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
• 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.

• 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
Morton for
by Sir William
the removal of
mandibular tumor.
• Experiment was published in
Boston daily journal. And led to
the discovery of Surgical
anesthesia.
HISTORY

• 1853- Sir John Snow- Chloroform as anesthetic agent.
• 1913- Sir Chavalier Jack- 1st to use direct laryngoscopy for tracheal
intubation.
• 1934- Sir Ernest Volwiler. Synthesized 1st i.v anesthetic agent-
Thiopental.
• 1956- Sir Ivan Whiteside Magill- technique for Nasotracheal
intubation.
• 1967- Sir Peter Murphy, discovered fiberoptic endoscope.
HISTORY

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
consciousness,
depressed
produced
level of
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
respond purposefully
which patients
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 cannot be easily
aroused, but respond purposefully following
repeated or painful stimulations.the patient’s
ability to independentely maintain ventilatory
function may be impaired, and the patient may
require assistance in
airway. Cardiovascular
maintaining
function
a patent
is usually
maintained during deep sedation.
LEVELS OF SEDATION

• General Anesthesia
A drug-induced loss of consciousness-
during which patient is not arousable,
even by painful stimulation. The ability to
maintain ventilatory function is impaired.
Patients often 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

Minimal
Sedation
(anxiolysis)
Moderate
Sedation/
Analgesia
Deep
Sedation/
Analgesia
General
Anesthesia
Responsiveness Normal
response to
speech
Purposeful
response to
speech or
touch
Purposeful
response to
repeated or
painful
stimulation
No response,
even to pain
Airway Unaffected Remains open May need help
to maintain
airway
Often needs
help to
maintain
airway
Ventilation Unaffected Adequate May not be
adequate
Often require
ventilatory
support
Cardiovascular
Function
Unaffected Usually
maintained
Usually
maintained
May be
impaired
LEVELS OF SEDATION

• 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

SEQUENCE OF DEPRESSION IN
CENTRAL NERVOUS SYSTEM
CEREBRAL
CORTEX
CEREBELLUM
SPINAL
CORD
MEDULLARY
CENTERS

• Major target- Ligand gated ion channels.
• GABAA receptorgated Cl¯ channel.
Examples –
Many inhalation anesthetics,
barbiturates,
benzodiazepines and
propofol.
MECHANISM OF ACTION
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

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.
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)
PRE-ANAESTHETIC
EVALUATION

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PRE-ANAESTHETIC
EVALUATION

1. Medical history questionnaire
2. Physical examination
3. Lab investigations
PRE-ANAESTHETIC
EVALUATION

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 systems
Medical history
questionnaire

Physical Examination
1. Vital Signs
2. Airway
3. Heart
4. Lungs
5. Extremities
6. Neurologic examination

Airway
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
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.’’

Airway Evaluation
• Mallampati Classification
• Thyromental Distance
• Sternomental Distance
• Maximum vertical opening (MVO)

Mallampati Classification
https://www.speareducation.com/spear-review/wp-content/uploads/2014/05/Tonsil-Grading-2.png

Thyromental Distance
https://i.ytimg.com/vi/blqwvuA7NKw/maxresdefault.jpg

Thyromental Distance

Sternomental Distance
http://clinicalgate.com/wp-content/uploads/2015/04/B9780702035258000021_f02-03-
9780702035258.jpg

Sternomental Distance

Maximum vertical opening
(MVO)

Airway Evaluation
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)
• Categories of difficult airway
1.Known or expected difficult airway.
2•.H/Poodteifnfitciualty/fdaiiflefidcuinlttauibrwataioy
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3•.H/oUndeifxfipceucltt/efdaidleidffimcualtskaivrewnatyil.ation.
•Conditions associated with difficult airway.
-Acquired and congenital

Categories of difficult airway
2. Potentially difficult airway.
• Limited neck extention.
• Limited mouth opening.
• Receding mandible.
• Mallampati class III or IV
• Short thyromental distance
Airway Evaluation

Categories of difficult airway
3. Unexpected difficult airway.
• Supraglotic mass.
• Hyperplasia of lingual tonsils.
• Missed evidence of difficult airway
Airway Evaluation

Airway Evaluation
DIFFICULT
AIRWAY

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

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

• CONSENT
PRE OPERATIVE
PREPARATION

• PREMEDICATIONS
• Relief of apprehension or anxiety
• Sedation
• Analgesia
• Amnesia of preoperative events
• Prevention of nausea and vomiting
• Vagolytic actions
• Fascilitation of anaesthetic induction
• Prophylaxis against allergies.
PRE OPERATIVE
PREPARATION

GROUP DRUGS EFFECT SIDE EFFECTS DOSES
Benzodiazepines Diazepam
Midazolam
Sedation
Amnesia
anxiolysis
-CNS depression when
given with opoids
0.04-0.08mg/kg IV/IM
Opoids Pethidine
Morphine
Fentanyl
Sedation
Analgesia
-Resp. depression
-PONV
-50-100mg IV/IM
-1-2μgm/Kg
Barbiturates Thiopental
Methohexital
Sedation -Antianalgesic effect
-Cardio respiratory
depression
-3-5mg/kg IV
-1-1.5mg/kg IV
Phenothiazines Chlorpromazine
Promithazine
Sedation
Anticholinergic
Antiemetic
-Hypotension
- Restlessness
-10-25mg IV/IM
Butyrophenones Haloperidol
Droperidol
Antiemetic -Dysphoria
-Restlessness
-2.5-7.5mg IV/Im
Anticholinergic Atropine
Glycopyrolate
Scopolamine
Vagolytic
Antisialogogue
Sedation, Amnesia
Dry mouth
Restlessness
-0.12mg/kg
-0.04mg/kg
Antiemetic Ranitidine
Metoclopramide
ondansetron
Antiemetic - -50-100mg IV
-5-20mg IV
-4mg IV

• Fasting Guidelines
PRE OPERATIVE
PREPARATION
AGE CLEAR FLUIDS NON-CLEAR
FLUIDS/SOLIDS
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
PREPARATION
• PRE OPERATIVE ORDERS

• MASKS
ANESTHETIC
EQUIPMENT
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

• LARYNGOSCOPE
ANESTHETIC
EQUIPMENT

ANESTHETIC
EQUIPMENT

• ENDOTRACHEAL TUBES
ANESTHETIC
EQUIPMENT

• Adjuncts To Intubation
• BOUGIE
ANESTHETIC
EQUIPMENT

• Adjuncts To Intubation
• LIGHTED STYLET
ANESTHETIC
EQUIPMENT

• OROPHARYNGEAL AIRWAY
ANESTHETIC
EQUIPMENT

• NASOPHARYNGEAL AIRWAY
ANESTHETIC
EQUIPMENT

• LARYNGEAL MASK AIRWAY
ANESTHETIC
EQUIPMENT

• RESUSCITATION BAG
ANESTHETIC
EQUIPMENT

MONITORING
EQUIPMENTS
• BLOOD PRESSURE MONITOR

MONITORING
EQUIPMENTS
• CARDIOSCOPE

MONITORING
EQUIPMENTS
• PULSE OXIMETER

MONITORING
EQUIPMENTS
• CAPNOGRAPH

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

• IDEAL PROPERTIES
Chemically stable
•
INHALATIONAL
ANESTHETICS
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• rCaappidalbyleviaolfunpgrso.ducing unconciousness with analgesia and
some degree of muscle relaxation.

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)
INHALATIONAL
ANESTHETICS

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.
INHALATIONAL
ANESTHETICS

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
INHALATIONAL
ANESTHETICS

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.
INHALATIONAL
ANESTHETICS

OIL GA
EFFICIENT
INHALATIONAL
ANESTHETICS

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
INHALATIONAL
ANESTHETICS

INHALATIONAL
ANESTHETICS
NITROUS OXIDE
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• NITROUS OXIDE
• The second-gas effect
The ability of the large volume uptake of one gas (first gas) to
accelerate 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%)
INHALATIONAL
ANESTHETICS

• 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 N2O.
INHALATIONAL
ANESTHETICS

• HALOTHANE(Fluothane)
• 2-bromo-2-chloro-1,1,1-trifloroethane
• Non flammable,non explosive.
• Pleasant smell, non irritating.
• Induction 2-4 %
• Maintanence 1-2%.
• BP falls in proportion to the vapour inhaled.
• Depression of respiratory centre.
• Respiratory rate increases, depth of respiration decreases.
INHALATIONAL
ANESTHETICS

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

• ISOFLURANE(Sofane)
• 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
INHALATIONAL
ANESTHETICS

• 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
INHALATIONAL
ANESTHETICS

• DESFLURANE
• 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
INHALATIONAL
ANESTHETICS

• 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
,
smilar to isoflurane.
• Exhaled unchanged and more rapidly.
INHALATIONAL
ANESTHETICS

• SEVOFLURANE
• Nonflammable fluorinated isopropyl ether.
• Properties intermidiate between isoflurane and
desflurane.
• Iduction 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.
INHALATIONAL
ANESTHETICS

• 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
INHALATIONAL
ANESTHETICS

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

• THIOPENTAL
Dose-
• 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.
dependent suppression of CNS activity
• Contraindicated: porphyria , status asthematicus.
INTRAVENOUS
ANESTHETICS

• BENZODIAZIPINES
• 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.
INTRAVENOUS
ANESTHETICS

• BENZODIAZIPINES
• 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
INTRAVENOUS
ANESTHETICS

• FENTANYL
• 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.
INTRAVENOUS
ANESTHETICS

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

• KETAMINE
maintaining
• Dissociative amnesia
• Profound amnesia/ analgesia despite
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
INTRAVENOUS
ANESTHETICS

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

• PROPOFOL
• Exitation 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.
INTRAVENOUS
ANESTHETICS

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

• ETOMIDATE
• 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.
INTRAVENOUS
ANESTHETICS

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

INDUCTION
• 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

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

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

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

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,
536 (August 2013)
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

Surgical
Anaesthesia
• 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
536 (August 2013)

REVERSAL
•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

POST OPERATIVE CARE
• Shifted to recovery for Post op 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

POST ANESTHESIA
RECOVERY SCORE
• ACTIVITY
2=Move all extremities voluntarily or on command
1= Move two extremities.
0= Unable to move extremities.
• RESPIRATION
2 = Breathes deeply and coughs freely, shallow /limited breathing
1 = Requires assistance
0 = Apnic
• CIRCULATION
2 = BP+20mm Hg of preanesthetic level
1 = BP+20-50 mm Hg of preanesthetic level
0 = BP+50 mm Hg of preanesthetic leve

• CONCIOUSNESS
2= Fully awake
1= Arousable on calling
0= Not responding
• OXYGEN SATURATION
2 = > 92% on room air
1 = supplemental oxygen req. Tomaintain SpO2 >90%
0 = SpO2< 92% with oxygen supplementation.
POST ANESTHESIA
RECOVERY SCORE

COMPLICATIONS OF
GENERALANAESTHESIA
• Pre operative Period
• During maintenance of GA
- Related to anesthetic drug used
- Anesthetic technique
- Equipment failure
- Medical condition
- Surgical pathology
• Post operative period
- Related to anesthetic drug used
- Anesthetic technique
- Intubation technique
- Pain
- Infection
- Medical condition

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

• WHEEZING
• Causes-
1 Reflex stimulation under light anesthesia
- Tracheal/ surgical stimulation.
2. Endotracheal tubes- kinking, overdistended, inserted
too far
3. Anaphylactic reaction
4. Aspiration
5. Pnemothorax.
COMPLICATIONS OF
GENERALANAESTHESIA

• WHEEZING
• 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.
COMPLICATIONS OF
GENERALANAESTHESIA

• MALIGNANT HYPERTHERMIA
• 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 reticulam leading to sustained
muscle contraction. This results in signs of hypermetabolism
like tachycardia, acidosis, hypercarbia, hypoxemia and
hyperthermia.
COMPLICATIONS OF
GENERALANAESTHESIA

• MALIGNANT HYPERTHERMIA
• Treatment
• 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
COMPLICATIONS OF
GENERALANAESTHESIA

• LARYNGOSPASM
• Caused by irritative stimulus of the upper airway during light
plane of anesthesia.
• The common noxious stimuli to elicit reflex are secretions,
vomitus and inhalation of pungent volatile anesthetic agents.
• Reflex closure of voca cords causing partial or total glottc
obstruction.
• Hypoxia, hypercarbia, and acidosis.
COMPLICATIONS OF
GENERALANAESTHESIA

• LARYNGOSPASM
• Treatment-
• Continue positive pressure ventilation
• Deepening of anesthetic level.
• Removal of stimulus.
• Muscle relaxant- Succinylcholine- 10-20 mg IV
COMPLICATIONS OF
GENERALANAESTHESIA

• BRONCHOSPASM
• Centrally mediated or due to local response of airway
• Stimulated by histamine release( morphine,atracurium)
• Characteristic wheezing, tachypnea in awake patients.
• Treatment-
• Correction of endotracheal tube
• Deepening of anesthetic level.
• Adequate hydration of imspired air.
• Aminophylline IV 250-500mg slowly.
• Salbutamol IV. 250 mg/2.5mg inhalation
COMPLICATIONS OF
GENERALANAESTHESIA

• POST OPERATIVE NAUSEA AND VOMITING
• 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
COMPLICATIONS OF
GENERALANAESTHESIA

• POST OPERATIVE NAUSEA AND VOMITING
• Treatment
• 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
COMPLICATIONS OF
GENERALANAESTHESIA

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

CNS
Effects
Increasing dose
Coma Barbiturates
Benzodiazepines
Hypnosis
Sedation, disinhibition, anxiolysis Possible selective
anticonvulsant & muscle-
relaxing activity
Dose Response Relationships
Anesthesia
Medullary depression

• 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 clinics of
•

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