Question

3-5 minutes of preoxygenation at greater than 6 L/min of 100% FiO2 (gives you 10 minutes of safe apnea time) is equivalent to?

A) Increasing lung compliance
B) Decreasing functional residual capacity
C) Creating an oxygen reservoir in the functional residual capacity
D) Reducing cardiac output

Answer 1

3-5 minutes of preoxygenation at greater than 6 L/min of 100% FiO2 (gives you 10 minutes of safe apnea time) is equivalent to creating an oxygen reservoir in the functional residual capacity (Option C). This process does not increase lung compliance, decrease functional residual capacity, or reduce cardiac output.

Step-by-step explanation:

Preoxygenation at greater than 6 L/min of 100% FiO2 creates an oxygen reservoir in the functional residual capacity, providing safety during periods of apnea by preventing rapid desaturation.

This practice does not necessarily increase lung compliance or decrease functional residual capacity.

Instead, it serves to fill the lungs with oxygen, increasing the O₂ store and thereby providing a buffer during periods of apnea, such as during intubation or anesthesia induction.

It allows for a longer period where the patient can safely be without ventilation (safe apnea time).

Preoxygenation is thus important in clinical settings to ensure patient safety. It does not reduce cardiac output but helps in preventing rapid desaturation.

The buildup of oxygen in the FRC ensures that there is a larger amount of oxygen available for gas exchange during apnea.

Hence, the correct answer is Option C.