High-flow Nasal Oxygen Versus Standard Flow Facemask Preoxygenation in Pregnant Patients: A Randomized Physiological Study

Abstract

(Anaesthesia. 2019;75:450–456) While preoxygenation is an important component of safe general anesthesia, it is often suboptimal for obstetric patients. This is due to several factors including air entrainment even with a tight-fitting mask, the need for rapid delivery of the fetus in many situations, and human factor issues. For obstetric patients, an end-tidal oxygen concentration (EtO2) ≥90% is recommended before initiating rapid sequence induction and tracheal intubation. The standard practice for preoxygenation in this population is usually either 3 minutes of tidal volume breathing or 8 vital capacity breaths with facemask administration of 100% oxygen at 15 L/min. Growing in popularity for nonobstetric patients, including children, is high-flow nasal oxygen (HFNO) to increase the time to desaturation during induction of general anesthesia; however, literature on HFNO for obstetric patients is sparse. This study aimed to determine whether preoxygenation with HFNO (30 to 70 L/min oxygen flow) via nasal prongs is as effective as the recommended preoxygenation using standard 15 L/min oxygen administered via a tight-fitting facemask in obstetric patients.