MCQS

1. INHALATIONAL ANAESTHETICS
MCQS

2. Q1. Index of potency of general anesthesia
is
a. Minimum alveolar concentration
b. Diffusion coefficient
c. Dead space coefficient
d. Alveolar blood concentration
Ans: A)Minimum alveolar concentration

3. Minimum alveolar concentration
 It is the alveolar concentration of inhaled
anesthetic that prevents movement in 50
percent of patients in response to standard
stimulus (eg standard stimulus)
 Best measure of anesthetic potency
 primarily mediated by anaesthetic action
in spinal cord

4. Q2. Potency of inhalational anaesthetic
depends on
a. Blood gas partition coefficient
b. Oil gas partition coefficient
c. Gas pressure
d. Blood pressure
Ans B)Oil gas partition coefficient

5. Partition coefficient
 The relative solubilities of an anesthetic in
air, blood & tissues are expressed partial
coefficient
 Blood gas partition coefficient measures
solubility of GA .Most important factor in
determining the uptake agent and so the
speed of induction and recovery.
 Oil-gas partition coefficient (lipid solubility)
measures anesthetic potency.

6. Q3. Which one of the following is the
fastest acting agent?
a. Halothane
b. Isoflurane
c. Ether
d. Sevoflurane
Ans D)Sevoflurane

7.  Blood gas partition coefficient measures solubility of
GA .Most important factor in determining the uptake
agent and so the speed of induction and recovery.
 Agents in increasing order of B/G coefficients
Xe(0.14) > Desflurane(0.42) >
Cyclopropane (0.44) > N2O (0.47) > Sevoflurane(0.69)
> Isoflurane(1.38) > Enflurane(1.8) >
Halothane(2.4) > Chloroform(8) > Trilene(9) >
Ether(12) > Methoxyflurane(15)

8. Q4. All of the following factors decrease
the minimum alveolar concentration
(MAC) of an inhalational anaesthetic
agent except
a. Hypothermia
b. Hyponatremia
c. Hypocalcemia
d. Anaemia
Ans C)Hypocalcemia

9. Factors affecting increase on MAC
 Young
 Chronic abuse of alcohol
 Hypernatremia
 Acute Amphetamine toxication
 Cocaine, Ephedrine

10. Factors affecting decrease on MAC
 Hypothermia, Hyperthermia
 Elderly
 Anemia
 Pregnancy
 PaO2<40mmHg,PaCO2>95mmHg
 Drugs:
Local anesthetics, Opiods,Ketamine,Barbiturates,
Verampil, Lithium,Symptholytics.
 Chronic use of Amphetamine

11. Q5. True about xenon anaesthesia
a. Rapid induction and recovery
b. Low potency
c. High blood solubility
d. Non explosive
e. Heavier than air
Ans)A,D,E

12. Xenon
 is inert, colorless, odorless, non irritating, non
inflammable and environmental friendly
 more potent than N2O
 It is neuro and cardioprotective
 non teratogenic and safe(to liver and
kidney)anesthetic
 Xenon's B/G partition coefficient is the lowest,
resulting in rapid induction and recovery.

13. Q6. Pungent volatile anaesthetic is
a. Halothane
b. Isoflurane
c. Sevoflurane
d. Desflurane
e. Nitrous oxide
Ans) B and D

14.  Pungent volatile anaesthetic agents are
 Desflurane
 Isoflurane
 Enflurane
 Ether

15. Q7. Which of the following inhaled gas is
used to decrease pulmonary artery in
adults and infants?
a. Nitrous oxide
b. Nitrogen dioxide
c. Nitric oxide
d. Nitrogen
Ans C Nitric oxide

16.  Nitric oxide or endothelium derived relaxing factor is
synthesised from L-arginine by nitric oxide synthase
(NOS) enzyme in endothelium of blood vessels.
 Physiologically it causes vasodilation and
decreases vascular resistance throughout the body.
 Inhaled NO is a selective pulmonary –vasodilator
decreases pulmonary artery pressure in infants and
adults and improves V/P ratio..So it is used in
treatment of pulmonary artery pressure

17. Q8. Diffusion hypoxia is seen during
a. Induction of anaesthesia
b. Recovering anaesthesia
c. Pre operatively
d. Post operatively
Ans B) Recovering anesthesia

18.  Diffusion hypoxia is seen during recovery
phase after discontinuation of prolonged
N2O anaesthesia .
 It can be prevented by continuing 100 % O2
inhalation for few minutes after
discontinuing N2O

19. Q9. Use of nitrous oxide is contraindicated
in all of the following surgeries except
a. Cochlear implant
b. Microlaryngeal surgery
c. Vitreoretinal surgery
d. Exentration surgery
Ans D)Exentration surgery

20.  Excentration is enclueation + wide
dissection of periorbital tissue.In it there is
no closed space formation so N2O can be
used.
 In microlaryngeal lesser surgery,N2O is
contradicated due to risk of airway fire.

21. Q10. Soda lime circuit is not used with
a. Enflurane
b. Isoflurane
c. Methoxyflurane
d. Trilene
Ans D) Trilene

22.  Sodalime with trilene forms phosgene
(neurotoxic) gas.
 It should not be used with:
 Chloroform
 Trilene
 Sevoflurane

23. Q11. Stages of anaesthesia was
established by
a. Ether
b. N2O
c. Halothane
d. Chloroform
Ans A) Ether

24.  Guedel’s staging of anesthesia was given for ether
 Stage I -Analgesia
 Stage II-Delirium or Excitement Partially dilated pupil
 Stage III- has 4 planes
 1 moving eye to fixed eye
 2 corneal or laryngeal reflex lost
 3 light reflex lost
 4Intercostal paralysis
 Abdominal respiration
 Pupils fully dilated
 Stage IV-Medullary Paralysis

25. Q12. Anaesthesia agent with least
analgesic property
a. N2O
b. Halothane
c. Ether
d. Propane
Ans B)Halothane

26. Halothane
 is a potent,non inflammable ,non toxic,colourless
liquid with relatively non pungent vapour
 Anesthesia agent with least analgesic agent
 It’s a bronchodilator,uterine relaxant and vasodilator
 Anesthesia of choice for uterine contraction and
inversion

27. Q13. Which of them are the following
contraindications for halothane use?
a. Middle age
b. Recent halothane use
c. Associated liver pathology
d. Obesity
Ans-B and C

28. Contraindications of halothane
 Liver dysfunction
 Halothane use with in 3 months
 Hypovolemia & severe cardiac disease
 Pheochromocytoma and exogenous
catecholamines administration

29. Q14. In increased ICT, agent used for
anaesthesia
a. Isoflurane
b. N2O
c. Trilene
d. Ether
Ans A) Isoflurane

30. Isoflurane
 is anesthesia of choice for neurosurgical
procedures ,renal failure and myasthenia gravis
 Avoided in ischaemic heart disease
 Cause coronary steal syndrome
 used in daycare anesthesia

31. Q15. Which of the following is/are false?
a. Enflurane interacts with sodalime
b. Sevoflurane causes seizures
c. Ketamine acts through GABA-A
receptors
d. MAC indicates potency of inhalational
agents
Ans B,A

32.  Sevoflurane ,isoflurane and desflurane have
anticonvulsant properties.
 Enflurane causes epileptiform changes (more
commonly during hypocapnia)hence should be
avoided in epilepsy.
 Enflurane interacts with sodalime but produce
clinically insignificant amount of carbonmonoxide
 Ketamine is a noncompetitive NMDA (glutamate)
receptor antagonist
 Propofol has smooth and rapid induction and rapid
recovery.