MODULE 1: INTRODUCTION & BALANCED ANESTHESIA

Q1: The first successful demonstration of anesthesia is done by whom and when was it done?

Answer: The first successful demonstration of anesthesia was performed by Dr. William T.G. Morton on October 16, 1846 at the Massachusetts General Hospital in Boston. He demonstrated the use of ether inhalation for anesthesia during a surgical procedure to remove a tumor from the neck of a patient named Gilbert Abbott. This historic event is known as the "Ether Day" and marked the beginning of modern anesthesia.

Q2: Define balanced anesthesia

Answer: Balanced anesthesia is a technique that combines different types of anesthetic drugs to achieve the desired effects of general anesthesia while minimizing the side effects of individual drugs. It typically involves the use of:

• Hypnotics (for unconsciousness)
• Analgesics (for pain relief)
• Muscle relaxants (for muscle paralysis)
• Inhalational agents (for maintenance)

The goal is to provide optimal anesthesia with minimal physiologic stress and faster recovery.

Q3: Enumerate the stages of anesthesia

Answer: The stages of anesthesia according to Guedel's classification are:

Stage 1 (Induction/Analgesia):

• Patient conscious but drowsy
• Analgesia present
• Respiration normal

Stage 2 (Excitement/Delirium):

• Loss of consciousness
• Irregular respiration
• Reflexes still present
• Possible excitement movements

Stage 3 (Surgical Anesthesia):

• Divided into 4 planes:
  • Plane 1: Eyeballs fixed centrally, relaxed
  • Plane 2: Eyelashes absent, corneal reflex absent
  • Plane 3: Pupil dilation, no response to light
  • Plane 4: Maximum relaxation, surgery possible

Stage 4 (Medullary Depression):

• Dangerous stage
• Complete respiratory and circulatory depression
• Immediate intervention required

Q4: Write different methods for measuring blood pressure

Answer: Methods for measuring blood pressure:

Non-invasive Methods:

1. Auscultatory Method (Mercury Sphygmomanometer)

   • Korotkoff sounds
   • Most accurate method

2. Automated Oscillometric Devices

   • Uses pressure oscillations
   • Commonly used in OR and ICU

3. Palpation Method

   • Radial artery palpation
   • Less accurate, used when auscultation difficult

4. Doppler Method

   • Uses ultrasound
   • For low flow states

Invasive Methods:

1. Arterial Line Monitoring
   • Continuous real-time BP measurement
   • Used in major surgeries and critical care

Q5: What is BURP?

Answer:BURP stands for:

• Backward
• Upward
• Rightward
• Pressure

BURP is a maneuver used during laryngoscopy to improve visualization of the vocal cords by applying pressure on the thyroid cartilage. It's performed by an assistant to help with difficult intubation by:

• Displacing the larynx posteriorly and superiorly
• Rotating it to the right
• Improving glottic view

Q6: Graph of pulse oximetry is also known as

Answer: The graph of pulse oximetry is also known as "Plethysmograph" or "Pulse Oximetry Waveform". It shows the pulsatile blood volume changes and is used to assess:

• Perfusion status
• Pulse rate and rhythm
• Respiratory patterns
• Circulatory adequacy

Q7: What are the different types of drugs used in GA?

Answer: Drugs used in General Anesthesia:

1. Induction Agents:

• Propofol (2-2.5 mg/kg IV)
• Thiopentone (3-5 mg/kg IV)
• Etomidate (0.3 mg/kg IV)
• Ketamine (1-2 mg/kg IV)

2. Inhalational Agents:

• Sevoflurane (1-3 MAC)
• Isoflurane (1-1.5 MAC)
• Desflurane (3-6 MAC)
• Halothane (0.7-1 MAC)

3. Opioids:

• Fentanyl (2-10 mcg/kg)
• Morphine (0.1-0.2 mg/kg)
• Remifentanil (0.5-1 mcg/kg)

4. Muscle Relaxants:

• Succinylcholine (1-2 mg/kg)
• Atracurium (0.5 mg/kg)
• Vecuronium (0.1 mg/kg)

5. Reversal Agents:

• Neostigmine (0.05 mg/kg)
• Sugammadex (2-4 mg/kg)

Q8: What are the different types of opioids and IV agents used in GA?

Answer:

Opioids Used in GA:

1. Strong Opioids:

   • Fentanyl: 2-10 mcg/kg
   • Sufentanil: 0.1-0.5 mcg/kg
   • Alfentanil: 10-50 mcg/kg
   • Remifentanil: 0.25-1 mcg/kg

2. Moderate Opioids:

   • Morphine: 0.1-0.2 mg/kg
   • Meperidine: 1-2 mg/kg

IV Induction Agents:

1. Ultra-short Acting:

   • Propofol: 2-2.5 mg/kg
   • Thiopentone: 3-5 mg/kg

2. Short Acting:

   • Etomidate: 0.3 mg/kg
   • Ketamine: 1-2 mg/kg

Q9: What are the types of muscle relaxants used in GA and mention their dosages?

Answer:

Depolarizing Muscle Relaxants:

• Succinylcholine: 1-2 mg/kg IV
  • Onset: 30-60 seconds
  • Duration: 3-5 minutes

Non-Depolarizing Muscle Relaxants:

Aminosteroid Group:

• Vecuronium: 0.08-0.1 mg/kg
• Rocuronium: 0.6-1.2 mg/kg
• Pancuronium: 0.08-0.1 mg/kg

Benzylisoquinolinium Group:

• Atracurium: 0.5-0.6 mg/kg
• Cisatracurium: 0.15-0.2 mg/kg
• D-tubocurarine: 0.3-0.6 mg/kg

Reversal Dosages:

• Neostigmine: 0.05-0.07 mg/kg (max 5 mg)
• Sugammadex: 2-4 mg/kg depending on TOF ratio

Q10: What are the reversal agents that give examples?

Answer:

Reversal Agents:

For Non-Depolarizing Muscle Relaxants:

1. Acetylcholinesterase Inhibitors:

   • Neostigmine: 0.05 mg/kg IV (with atropine/glycopyrrolate)
   • Edrophonium: 0.5-1 mg/kg IV
   • Pyridostigmine: 0.1-0.25 mg/kg IV

2. Selective Relaxant Binding Agents:

   • Sugammadex: 2-16 mg/kg IV (depending on depth of blockade)

For Benzodiazepines:

• Flumazenil: 0.2-0.5 mg IV (repeated to max 3 mg)

For Opioids:

• Naloxone: 0.4-2 mg IV (repeated as needed)

Q11: What are the agents used in balanced anesthesia?

Answer: Agents used in Balanced Anesthesia:

Combination Approach:

1. Hypnotic: Propofol or Thiopentone
2. Analgesic: Fentanyl or Morphine
3. Muscle Relaxant: Vecuronium or Atracurium
4. Inhalational Agent: Sevoflurane or Isoflurane

Example Protocol:

• Induction: Propofol 2 mg/kg + Fentanyl 2 mcg/kg + Succinylcholine 1.5 mg/kg
• Maintenance: Sevoflurane 1-2 MAC + Fentanyl infusion + Vecuronium
• Reversal: Neostigmine 0.05 mg/kg + Glycopyrrolate 0.01 mg/kg

Q12: What is BURP and mention when a condition is used?

Answer:BURP (Backward, Upward, Rightward Pressure) is used in difficult intubation scenarios:

When Used:

• Grade 3-4 laryngoscopy view
• Cannot visualize vocal cords
• Failed first intubation attempt
• Anticipated difficult airway

Technique:

• Apply pressure on thyroid cartilage
• Displace posteriorly and superiorly
• Rotate to right
• Helps visualize glottic opening

Q13: Write the mnemonic of Anesthesia

Answer: Common Mnemonics for Anesthesia:

STAGES OF ANESTHESIA:

• Surgical
• Toxicity
• Analgesia
• General
• Excitation
• Sleep

ASA CLASSIFICATION:

• Alpha
• Sound
• Abnormal

LEMON AIRWAY ASSESSMENT:

• Look externally
• Evaluate 3-3-2 rule
• Mallampati
• Obstruction
• Neck mobility

Q14: What are the different drugs used in GA and their dosages

Answer:

Induction Agents:

• Propofol: 2-2.5 mg/kg IV
• Thiopentone: 3-5 mg/kg IV
• Etomidate: 0.3 mg/kg IV
• Ketamine: 1-2 mg/kg IV

Inhalational Agents:

• Sevoflurane: 1-3 MAC
• Isoflurane: 1-1.5 MAC
• Desflurane: 3-6 MAC

Opioids:

• Fentanyl: 2-10 mcg/kg
• Morphine: 0.1-0.2 mg/kg
• Remifentanil: 0.5-1 mcg/kg

Muscle Relaxants:

• Succinylcholine: 1-2 mg/kg
• Vecuronium: 0.08-0.1 mg/kg
• Rocuronium: 0.6-1.2 mg/kg

Reversal Agents:

• Neostigmine: 0.05 mg/kg
• Sugammadex: 2-4 mg/kg

Q15: What are SpO2, PaO2, EtCO2 and their normal values?

Answer:

SpO2 (Peripheral Oxygen Saturation):

• Normal Value: 95-100%
• Clinical Significance: Non-invasive measurement of oxygen saturation

PaO2 (Arterial Partial Pressure of Oxygen):

• Normal Value: 80-100 mmHg
• Clinical Significance: Measures dissolved oxygen in arterial blood

EtCO2 (End-Tidal Carbon Dioxide):

• Normal Value: 35-45 mmHg
• Clinical Significance:
  • Measures CO2 at end of expiration
  • Indicates adequate ventilation
  • Early indicator of complications

Q16: Write about preoxygenation

Answer:Preoxygenation is the administration of 100% oxygen before induction of anesthesia.

Purpose:

• Denitrogenate the lungs
• Increase oxygen reserves
• Extend safe apnea time
• Prevent hypoxia during induction

Methods:

1. Mask Preoxygenation:

   • 100% O2 for 3-5 minutes
   • Tight-fitting mask
   • Patient breathing spontaneously

2. Deep Breathing Technique:

   • 4 vital capacity breaths of 100% O2
   • Equivalent to 3 minutes of normal breathing

Benefits:

• 8-10 minutes of safe apnea time (vs 1-2 minutes without)
• Delayed onset of hypoxia
• Better tolerance of difficult intubation

Q17: What are the minimum standards of anesthesia

Answer:Minimum Standards for Safe Anesthesia:

Essential Monitoring (ASA Standards):

1. Oxygenation: Pulse oximetry
2. Ventilation: Capnography
3. Circulation: ECG, Blood pressure
4. Temperature: Core temperature monitoring

Equipment Requirements:

1. Anesthesia Machine: With safety features
2. Ventilator: Capability for controlled ventilation
3. Suction Apparatus: Ready for use
4. Emergency Equipment: Difficult airway cart
5. Drugs: Emergency and routine medications

Personnel:

1. Anesthesiologist: Trained and licensed
2. Assistant: Qualified anesthesia provider
3. Backup: Available for emergencies

Q18: Write any 5 major advantages of balanced anesthesia

Answer:Advantages of Balanced Anesthesia:

1. Reduced Drug Doses: Lower doses of individual drugs minimize side effects
2. Cardiovascular Stability: Better hemodynamic control
3. Faster Recovery: Shorter recovery time compared to deep anesthesia
4. Improved Analgesia: Better pain control during and after surgery
5. Flexible Dosage: Can adjust components based on patient needs
6. Lower Risk of Awareness: Multiple agents provide better unconsciousness
7. Reduced Post-op Nausea: Lower inhalational agent concentrations
8. Better Muscle Relaxation: Controlled paralysis when needed

Q19: Explain hypocapnia and causes

Answer:Hypocapnia (Low PaCO2):

• Definition: PaCO2 < 35 mmHg
• Normal PaCO2: 35-45 mmHg

Causes:

1. Hyperventilation:

   • Anxiety/panic
   • Pain
   • Fever
   • Sepsis

2. Mechanical Ventilation:

   • Excessive respiratory rate
   • Large tidal volumes
   • Incorrect settings

3. Medications:

   • Salicylates
   • Progesterone
   • Catecholamines

4. High Altitude: Lower atmospheric pressure

Effects:

• Respiratory alkalosis
• Cerebral vasoconstriction
• Reduced cerebral blood flow
• Decreased consciousness
• Cardiac arrhythmias

Q20: Define balanced anesthesia and general anesthesia

Answer:

Balanced Anesthesia: A technique combining multiple anesthetic drugs to achieve the components of general anesthesia (unconsciousness, analgesia, muscle relaxation) while minimizing side effects of individual drugs.

General Anesthesia: A state of controlled, reversible unconsciousness with:

• Hypnosis: Unconsciousness and amnesia
• Analgesia: Absence of pain sensation
• Muscle Relaxation: Prevention of movement
• Autonomic Blockade: Suppression of reflexes

Key Differences:

• Balanced Anesthesia: Uses drug combinations
• General Anesthesia: May use single agents or combinations
• Balanced Anesthesia: More controlled and titratable
• General Anesthesia: Broader term including various techniques