General Anaesthesia And Sedation In Oral And Maxillofacial Surgery Question And Answers

General Anaesthesia And Sedation In Oral And Maxillofacial Surgery Important Notes

1. Agents:

General Anaesthesia And Sedation In Oral And Maxillofacial Surgery Agents

2. Different Concentrations of Nitrous Oxide N2O:

General Anaesthesia And Sedation In Oral And Maxillofacial Surgery Different Concentrations Of Nitrous Oxide

3. Nitrous oxide

  • Also called laughing gas
  • Name given by Humphry Davy
  • First prepared by Joseph Priestly in 1774


  • Used as carrier gas
  • The maximum concentration of nitrous oxide which can be given is 66%
  • The blood gas coefficient is 0.47
  • It is non-inflammable, non-explosive
  • Good analgesia
  • Not a muscle relaxant

General Anaesthesia And Sedation In Oral And Maxillofacial Surgery Short Essays

Questions 1. Preanaesthetic evaluation.


  • To get an idea about the patient’s health
  • To educate the patient
  • To obtain consent


  • Patient’s medical history
  • Allergies to any drugs
  • Deleterious habits
  • Anaesthetic problems
  • The general health of the patient
  • CVS system
  • Respiratory system
  • Hepatic system

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  • GIT system
  • Renal system
  • Endocrine system
  • Haematological examination
  • Reproductive system
  • Vital signs

Questions 2. Premedication
Preanaesthetic medication


  • Objectives
  • Reduces anxiety
  • Analgesia
  • Amnesia
  • Antiemetic
  • Anti sialogogue
  • Sedation
  • Reduction of acidity
  • Prophylactic


General Anaesthesia And Sedation In Oral And Maxillofacial Surgery Drugs

Question 3. IV Sedation

Advantages of IV Sedation:

  • Effective
  • Rapid onset
  • Control of secretion
  • Less emetic
  • Diminished gag reflex
  • Diminished motor disturbances

Disadvantages of IV Sedation:

  • Monitoring required
  • Delayed recovery

Drugs Used:

  • Diazepam-2-5 mg
  • Ketamine-1-2 mg/kg IV
  • Promethazine25 mg
  • Pethidine – 50 mg

Questions 4. Indications & complications of GA.

Indications of GA

Complications of GA

Indications of GA:

  • Extensive restoration along with extraction
  • In young patients
  • Uncooperative patients
  • Acute infections
  • Allergy to LA
  • Failure to LA
  • Failure to achieve sedation

Complications of GA:

  • Common Complications:
    • Coughing
    • Hiccups
    • Wheezing
    • Cyanosis
    • Cardiac arrhythmia
    • Laryngospasm
  • Complications: Due to Position:
    • Nerve injury
    • Air embolism

Post-Operative Complication:

  • Nausea & vomiting
  • Hypertension
  • Infection
  • Restlessness
  • Shivering
  • Respiratory obstruction

General Anaesthesia And Sedation In Oral And Maxillofacial Surgery Short Question And Answers

Questions 1. Infiltration anaesthesia.

Infiltration anaesthesia

  • It is a method of local anaesthesia
  • Injection of a local anaesthetic solution directly into the tissue can be
    1. Superficial-only into the skin or
    2. Deep into deeper structures
      • Duration can be doubled by adrenaline 1:200000
      • Adrenaline should not be used
      • Around end arteries to avoid necrosis
      • Intra-cutaneously to avoid sloughing
  • Drugs used:
    • Lignocaine
      • Procaine
      • Bupivacaine

Advantages of Infiltration Anaesthesia:

  • Provide anaesthesia without disrupting normal bodily functions

Disadvantages of Infiltration anaesthesia:

  • Systemic toxicity may occur in major surgeries

Uses of Infiltration Anaesthesia:

  • For minor procedures like incisions, drainage of an abscess, excision etc

Question 2. Role of muscle relaxants in General Anaesthesia

Role of muscle relaxants in General Anaesthesia

  • Creates laryngeal relaxation
  • Enables intubation
  • Stops spontaneous breathing so the patient must be ventilated till the effect of anaesthesia

Drugs Include:

  1. Suxamethonium:
    • Short-acting
    • Rapid recovery
  2. Pancuronium:
    • Non-depolarizing
    • Siow onset of action
    • Long-lasting effect
    • Effect is reversible

Questions 3. Assessment for general anaesthesia.

Assessment for general anaesthesia

By the American Society of Anaesthesiologists ASA.

  1. ASA 1:
    • No disturbances either systemic or physiological
  2. ASA 2:
    • Mild to moderate systemic disturbances
    • Can be treated surgically
    • Mild organic heart disese, diabetes, hypertension, anaemia, old age
  3. ASA 3:
    • Severe systemic disturbances Angina, MI, diabetes, etc
  4. ASA 4:
    • Life-threatening severe systemic disturbances
  5. ASA 5:
    • Patients not expected to survive for more than 24 hours
  6. ASA 6:
    • Emergency

Questions 4. Prilocaine.


  • Group: Amide
  • Potency: 2
  • Metabolism: Hydrolyzes by hepatic enzymes
  • pka: 7.9
  • pH of Plain Solution: 4.5
  • pH of Vasoconstrictor: 3-4
  • Plasma Half-Life: 1.6 hours
  • Effective Dental Concentration: 4%
  • Maximum Recommended Dose: 6 mg/kg body weight

Questions 5. Pentazocine.


It is a k receptor agonist

Advantages of Pentazocine:

  • Less respiratory depressant
  • Euphoria is seen in only low doses

Disadvantages of Pentazocine:

  • Weak antagonist
  • Increases BP & heart rate
  • Increases cardiac load
  • Dose: 50-100 mg orally

Adverse Effects of Pentazocine:

  • Sweating
  • Sedation
  • Dizziness
  • Nausea
  • Dysphoria
  • Nightmares
  • Hallucinations
  • Tolerance & dependence develop

Adverse Effects of Pentazocine

Uses of Pentazocine:

  • Postoperative & chronic pain

Questions 6. Stages of general anaesthesia.

Stages of general anaesthesia

  1. Stage Of Analgesia:
    • From the beginning of inhalation of the anaesthetic to loss of consciousness
  2. Stage Of Delirium:
    • From the loss of consciousness to the beginning of surgical anaesthesia
    • Associated with excitement
  3. Stage Of Surgical Anaesthesia:
    • Respiratory depression is seen
    • Gradual loss of reflexes
    • Relaxation of skeletal muscles
  4. Stage Of Medullary Paralysis:
    • Seen in overdoses
    • Medullary depression
    • Cessation of breathing
    • Circulatory failure
    • Death may follow

Questions 7. Ketamine.

Causes of Ketamine:

  • Dissociative anaesthesia:
    • Intense analgesic
    • Amnesia
    • The feeling of dissociative from one’s own body & surroundings

Advantages of Ketamine:

  • Profound analgesic
  • Doesn’t depress respiration
  • Can be used in asthmatic patients

Disadvantages of Ketamine:

  • Hallucinations
  • Dangerous in hypertensives
  • Increases cerebral blood flow
  • Increases intracranial pressure

Contraindications of Ketamine:

  • Hypertensive patients
  • CCF
  • Psychiatric disorders
  • Pregnancy

Questions 8. Halothane.


  • Colorless, volatile liquid with a sweet odour
  • Non-irritant
  • Non-inflammable

Advantages of Halothane:

  • Potent
  • Rapid induction
  • Rapid recovery
  • Rarely causes post-operative nausea & vomiting

Disadvantages of Halothane:

  • Neither good analgesia nor good muscle relaxant Myocardial depressant
  • Respiratory depressant
  • Causes malignant hyperthermia
  • Expensive

General Anaesthesia And Sedation In Oral And Maxillofacial Surgery Viva Voce

  • Methohexital is the most commonly used drug for general anaesthesia
  • The median cephalic vein is the optimum site for IV sedation
  • The N:O gas cylinder used in general anaesthesia is blue coloured
  • During general anaesthesia oxygen concentration of blood should not fall below 40%
  • Nowadays induction phase of general anaesthesia has been reduced because of the use of thiopentone sodium
  • If long-acting muscle relaxants are used during general anaesthesia their action is terminated by the use of neostigmine
  • The most common postoperative complication of general anaesthesia is nausea
  • The important sign a patient exhibits when the correct level of sedation is reached while using diazepam sedation is 50% ptosis of the eyelids
  • Complete blood count and urinalysis should be done before the use of general anaesthesia
  • Injection of contaminated alcohol can cause neurology- sis and may result in paraesthesia and permanent anaesthesia
  • Minor surgeries are carried out in Stage 1
  • Major surgeries are carried out in Stage 2
  • Nitrous oxide is laughing gas
  • The induction phase of general anaesthesia has been reduced nowadays due to the use of thiopentone sodium
  •  The N2O cylinder is blue
  • During general anaesthesia oxygen concentration of blood should not fall below 40%
  • Only nitrous oxide alone is not used as a general aesthetic agent due to difficulty in maintaining adequate oxygen concentration
  • Behavioural problem is the most common complication associated with nitrous oxide sedation

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