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During rapid sequence intubation (RSI) we endeavor to avoid positive pressure ventilation, prior to securing a definitive airway. As such, an adequate buffer of oxygen is necessary to ensure a safe apneic period. This process involves replacing the residual nitrogen in the lung with oxygen. It has been demonstrated that a standard nonrebreather (NRB) mask alone does not provide a high enough fractional concentration of oxygen (FiO2) to optimally denitrogenate the lungs (1). Even when a nasal cannula at 15L/min is utilized in addition to the NRB, the resulting FiO2 is not ideal. A bag-valve mask (BVM) with a one-way valve or PEEP valve has been demonstrated to provide oxygen concentrations close to that of an anesthesia circuit. But its effectiveness is drastically reduced if a proper mask seal is not maintained during the entire pre-oxygenation period (1). This is not always logistically possible in the chaos of an Emergency Department intubation.
A standard NRB with the addition of flush-rate oxygen appears to be a viable alternative. Recently published in Annals of Emergency Medicine, Driver et al demonstrated that a NRB with wall oxygen flow rates increased to maximum levels, rather than the standard 15L/min, provided end-tidal O2 (ET-O2) levels similar to an anesthesia circuit (2).
References
1. Hayes-bradley C, Lewis A, Burns B, Miller M. Efficacy of Nasal Cannula Oxygen as a Preoxygenation Adjunct in Emergency Airway Management. Ann Emerg Med. 2016;68(2):174-80.
2. Driver BE, Prekker ME, Kornas RL, Cales EK, Reardon RF. Flush Rate Oxygen for Emergency Airway Preoxygenation. Ann Emerg Med. 2016;