General Anesthetics

Question 1

Inducing Agents (IV route)

Answer 1

•Thiopentone
-Very fast action- Highly lipid soluble.
-Very short acting- due to Redistribution.

•Ketamine

•Propofol
-DOC; day care surgery.
-Injection is painful.

•Etomidate
-Agent of choice for CVS surgery.
-Causes adrenal suppression (S/E).

Question 2

Other drugs used in Day care Surgery

Answer 2

Dr -Desflurane (GA-IA)
Manmohan - Midazolam (BZD)
Singh -Sevoflurane (GA-IA)
Is -Isoflurane (GA-IA)
A -Alfentanil (Opioid Ag)
Prime - Propofol (GA-IV)
Minister -Mivacurium (PMR- NMJ#
-Non dep)

Question 3

Ketamin characters

Answer 3

K -Agent of Choice in Kids
E -Emergence Reaction
T -Thalamo-Cortical junction (site of
action) (Dissociative Anaesthesia)
A -Analgesic
M -Meals (can be given full stomach)
I -↑BP/IOP/ICP (so Agent of Choice in
Shock)
N -NMDA # (so avoided in Glaucoma)
E -Excellent bronchodilator

Question 4

General Anesthetics (IA)

Answer 4

(Inflammable)
Ether -Cautery is C/I
Chloroform - “”””
Cyclopropane- “”””
Trilene -“””

(Non inflammable)
N20. (MAC-104%)
Halothane
Enflurane (Max seizures, C/I Epilepsy)
Isoflurane (Safe in CVS/CNS)
Sevoflurane (Safe in CVS/CNS)
Desflurane
Methoxyflurane (Most potent & Slowest
Acting) (Nephrotoxic)
Xenon

Question 5

MAC

Answer 5

-Min conc of the agent required in
alveoli to produce anaesthesic effect

-MAC is inversely proportional to
Potency
• If MAC is max Potency - least.
(N2O and Xenon)
•If MAC is min→Potency is max.
(Methoxyflurane)

-N2O MAC - 104%.
• 100% of this agent - not produce
anaesthetic effect.
So N2O - supplemental agent.
(analgesic and muscle relaxant)

Question 6

Blood solubility

Answer 6

Blood solubility ♾️ 1/speed of action
Measured by - BGPC
•Highest BGPC (Slowest acting)
-Methoxyflurane
•Lowest BGPC (Fastest acting)
-Xenon>Desflurane

Question 7

Boyle’s machine

Answer 7

•Reduce the pressure of anaesthesic
agents.
-Avoid Barotrauma

•Safety mechanisms
-Colour coding
-Pin index safety system

Question 8

Boyle’s machine Color coding

Answer 8

•N2O: Blue
•Cyclopropane: Orange
•O2: Black and white
•Entonox: Blue and White
(N20+O2) 50% 50%

Question 9

Boyle’s machine Pin index safety system

Answer 9

•Air: 1,5
•O2: 2,5
•N20: 3,5
•Co2>7.5%: 1,6
•CO2<7.5%: 2,6
•Cyclopropane: 3,6
•Entonox: 7

Question 10

Halothane properties

Answer 10

-Risk of hepatitis
-Sensitizes the heart to Adrenaline
-Tocolytic effect
-C/I in pheocromocytoma Surgery

Question 11

Xenon properties

Answer 11

• ldeal anaesthetic agent.
1. Anaesthesic property
2. Analgesic property
3. Muscle relaxant action
4. Fastest induction and recovery
5. Smooth induction
6. Safe drug
-not easily available
-made in the laboratory
-very costly.