Certified Registered Nurse Anesthetist (CRNA) Practice Exam

What is the minimal time required for pre-oxygenation before induction of general anesthesia for a c-section?

1. 1 minute

2. 2 minutes

3. 3 minutes

4. 5 minutes

The correct answer is: 3 minutes

Pre-oxygenation prior to the induction of general anesthesia is a critical step, especially in situations like a cesarean section (C-section), where rapid changes in maternal oxygenation can occur. The primary goal of pre-oxygenation is to increase the oxygen reserves in the lungs, which can provide some time before the patient desaturates during the induction process. The minimal time recommended for effective pre-oxygenation is typically around three minutes. This duration allows for adequate diffusion of oxygen into the bloodstream, effectively increasing arterial oxygen levels and improving the patient’s ability to maintain adequate oxygenation during the period of apnea that occurs during intubation. During a C-section, it’s especially important to manage the airway carefully and to ensure the mother is well-oxygenated before any medication is administered that could potentially decrease her ability to breathe effectively. Pre-oxygenation for three minutes enhances the safety profile of the anesthesia process by providing a buffer against the rapid desaturation that can occur, particularly in patients with reduced functional reserve due to factors such as pregnancy and its physiological changes. Thus, three minutes stands as a standard practice duration, balancing efficiency and safety and ensuring optimal conditions for the induction of anesthesia in a potentially urgent surgical environment.