Preoxygenating

Preoxygenating is a medical procedure involving the administration of a high concentration of oxygen to a patient prior to a more invasive procedure, such as intubation or surgery. The primary goal of preoxygenation is to increase the patient's oxygen reserves in the lungs, thereby prolonging the period of safe apnea. Safe apnea is the duration a patient can tolerate without breathing, during which oxygen is absorbed from the lungs into the bloodstream.

This process is typically achieved by having the patient breathe 100% oxygen for a specific duration, usually three to five minutes, or through a series of vital capacity breaths. Vital capacity breaths involve the patient taking several deep breaths of high-flow oxygen, which can accelerate the denitrogenation process. Denitrogenation is the displacement of nitrogen from the alveoli with oxygen. Nitrogen normally constitutes about 78% of inhaled air and acts as a reservoir for gas in the lungs. By replacing nitrogen with oxygen, a larger pool of oxygen is available for absorption.

Preoxygenation is particularly important in emergency situations, patients with respiratory compromise, or those at higher risk of desaturation during airway manipulation. It provides a safety margin, allowing healthcare providers more time to secure the airway and manage any potential complications without immediate oxygen desaturation. While beneficial, it is not without potential risks, such as oxygen toxicity with prolonged exposure, though this is rarely a concern in the short timeframe of preoxygenation for procedures.