Anesthetic Techniques & Equipment Usage Flashcards

Per FDA labeling for sevoflurane, what minimum fresh gas flow is recommended for exposures exceeding 1 MAC-hour to limit Compound A exposure?

Answer: 2 L/min

Flows of at least 2 L/min are recommended beyond 1 MAC-hour, while 1 L/min is acceptable up to 1 MAC-hour.

Desflurane passing through a desiccated strong-base CO2 absorbent is most likely to produce which toxic byproduct?

Answer: Carbon monoxide

Dry absorbents degrade desflurane (and isoflurane) to carbon monoxide, unlike sevoflurane, which forms Compound A.

Why is the desflurane vaporizer electrically heated and pressurized?

Answer: Its boiling point is near room temperature and its vapor pressure is very high

Desflurane boils at about 23°C with a vapor pressure near 669 mmHg, so a variable-bypass vaporizer can't deliver it predictably.

A sevoflurane-specific variable-bypass vaporizer is mistakenly filled with isoflurane. What is the expected result?

Answer: Delivered potency higher than the dial setting

Isoflurane has a higher vapor pressure and lower MAC than sevoflurane, so more potent anesthetic is delivered than the dial shows.

Which machine safety feature reliably detects a pipeline crossover in which nitrous oxide is flowing through the oxygen line?

Answer: Inspired oxygen analyzer

Fail-safe devices and pressure alarms sense pressure, not gas identity, so only the oxygen analyzer detects a hypoxic mixture.

An oxygen E-cylinder reads 1,000 psig. At a flow of 5 L/min, approximately how long will it last?

Answer: About 1 hour

A full E-cylinder holds about 660 L at about 2,000 psig, so 1,000 psig leaves about 330 L, which lasts about 66 minutes at 5 L/min.

What is the most accurate way to estimate how much nitrous oxide remains in an E-cylinder?

Answer: Weigh the cylinder

Nitrous oxide is stored as a liquid, so pressure stays near 745 psig until about 75% has been used; only weight reflects the contents.