Rapid Preoxygenation: Four Deep Breaths or Eight?

Preoxygenation (PREOX) with 3 minutes of normal tidal volume breathing of 100% oxygen is recommended before rapid sequence intubation to permit several minutes of safe apnea time during intubation. Because traditional PREOX frequently is not possible, an accelerated method using 4 vital capacity breaths (VCB) in 30 seconds has been advocated, but has not proven as effective as the traditional method. In a study of 56 patients undergoing general anesthesia, these authors from Lebanon compared traditional PREOX with variations of 4 VCB in 30 seconds and 8 VCB in 60 seconds at oxygen flow rates of 5 to 20 L/min.

Traditional PREOX was superior to the 4 VCB method regardless of the oxygen flow rate; the resulting PaO₂ was 392(plusoverminus)72 tor…