Comprehensive Questions
with Verified Answers
Graded A+
1. 1 MAC sevo? Answer: ~2% (vs. 6% des, vs. 1.1% iso)
2. Does high/low CO increase rate of rise Fa/Fi? Answer: LOW cardiac output
increases rate of Fa/Fi and attects SOLUBLE gases more.
3. 2 life threatening complications TEE? Answer: Esophageal rupture, mediastinitis.
(proximity esophagus to LA eliminates problem of obtaining windows to view heart and permits
great detail)
4. Air filled trachea prevents TEE imaging of ? Answer: Ascending aorta.
5. Earliest recognized signs of MH (3)? Answer: Muscle rigidity (trismus), hypercarbia (in
ETco2 = *most sens
+ spef sx*), tachycardiac (later metabolic acidosis, hyperkalemia, ARF...
6. As temp increases, Pvapor? Answer: Vapor pressure of gas increases as temp
increases.
7. Pvapor / partial pressure N2O (at 20 C)? Answer: ~38,000 mmhg (you won't know
that tank is empty until it's very empty... when pressure reading of n2o cylinder *actually* drops,
very little nitrous actually left in cylinder)
8. 1 MAC N2O =? Answer: 104% (50% will not move in response to surgical stimulus)
9. MAC aware/awake of nitrous? Answer: 0.6 (vs. 0.4 sevo)
10. O Answer: g partition coefficient N2O? Answer: 1.3
11. B Answer: g partition coefficient N2O? Answer: ~0.45, about same as
desflurane which is LEAST soluble volatile i.e. FASTEST rate of induction
12. O Answer: g partition coefficient sevo? Answer: 50 (vs. 19 des, vs. ~200
halothane, vs. ~100 enflurane, vs. 90 iso)
13. B Answer: g partition coefficient sevo? Answer: 0.65 (vs. 0.45 des, vs. ~1.4
, iso)
14. Partial pressure sevo (at 20 C)? Answer: 157-160 mmhg
15. SVP sevo? Answer: 160mmhg
16. Partial pressure of anesthetic vapor (at a given temp) where
anesthetic liquid and vapor are in equilibrium? Answer: Saturated vapor pressure
(SVP). When the gas phase on top of the liquid phase is saturated by the molecules of vapor
(i.e. it contains as much vapor as it can handle). SVP sevo = 160 mmhg.
17. An increase in CO would inc/dec rate of rise of Fa/Fi for
relatively soluble inhalational anesthetics? Answer: DECREASE rate of rise for
SOLUBLE inhaled agents. Would *not* produce much ettect for insoluble agents. Shunts attect
insoluble >> soluble.
18. NEURO effects volatile vs. inhalational agents? Answer: DECOUPLE
cmro2 and CBF. Decreased CMRO2, however still increased CBF d/t vasodilation. *except
N2O*
19. RESP effects of gas? Answer: MV maintained, RR increased, TV decreased (rapid
shallow). Dose dependent decreased in ventilatory response to hypoxia + hypercapnia.
, 20. CV effects of gas? Answer: Dose dependent decreased SVR, decreased MAP. CO
maintained. *Halothane decreases myocardial contractility*
21. If Patm is lower (ie at higher altitudes), there must be INC/DEC
volume (or output) of sevo/iso for same vaporizer output? Answer:
INCREASED (*at higher altitude/lower Patm, the volume (%) delivered will be higher than
what the dial is set to*). However, *partial pressure of anesthetic gas remains the same* because
sevo/iso vaporizers deliver at a fixed partial pressure. VS des (heated vaporizer system) which delivers
at fixed % CONC. (end result - you need to increase dial to deliver more des at higher altitude but *not*
for sevo/iso).
22. The potency of an inhalational agent can be estimated by
knowing its solu- bility in what? Answer: OIL (o Answer: g part coett ~ mac)
23. T/F Answer: Anesthetics with greater blood Answer: gas
partition coefficients have lower solubility in blood. Answer: F
24. T/F Answer: Blood gas coefficient is an important
determinant of speed of anesthetic induction and recovery. Answer:
T
25. T/F Answer: Oil gas partition coefficient has been correlated
to anesthetic elimina- tion. Answer: F
26. T/F Answer: Tissue Answer: blood partition coefficients are
important to describe redistribu- tion of a chemical in the body
Answer: T
27. Which opioid causes LEAST reduction in MAC of volatile
anesthetics? Answer: Nal- buphine. Combining opioids with volatiles can significant reduce
MAC however opioids have ceiling ettect (unlike other IV induction agents eg propofol, other volatiles) at
which there is no further reduction in MAC despite increasing opioid doses. (also why opioids cannot be
used as sole induction agent).
28. Surgical factors a/w inc risk intra-op awareness (3)? Answer: Csx under
GA, cardiac, major trauma with EBL, TIVA
29. Patient factors a/w inc risk intra-op awareness (2)? Answer: H/o SUD,
chronic pain, diflcult/an- ticipated diflcult intubation. *red hair requires higher MAC but NO INC
RISK awareness*