With flush-rate oxygen, a non-rebreather mask was at least as good as a bag-valve-mask ventilation for intubation preoxygenation.
Many intubators using the rapid sequence intubation protocol use a bag-valve-mask (BVM) for preoxygenation. But in the absence of a good mask seal, a BVM may not be superior to a non-rebreather mask (NRBM). In two crossover studies in healthy volunteers, investigators compared these devices using flush-rate oxygen (supply valve wide open) and measuring expired oxygen (FeO2) after preoxygenation as the primary outcome. Each study enrolled about 30 volunteers and each participant served as his or her own control.
The first study assessed preoxygenation using the two devices (modified with a 1-way exhalation port) with and without a simulated mask leak. Mean FeO2 values were 81% for the NRBM, 76% for the BVM, and 30% for the BVM with a mask leak. The difference in FeO2 values between the NRBM and BVM was essentially equivalent, whereas the difference in values between the NRBM and the BVM with leak was highly significant. The second study compared use of the two devices with inspiratory assistance. In this study, mean FeO2 values were 83% for the NRBM with assistance versus 77% for the BVM with assistance, and this difference was statistically significant.
This study demonstrated that preoxygenation using a NRBM was as good, if not better, than preoxygenation using a BVM. Although, the best method utilizes a combination of a high-flow nasal cannula (to provide apneic oxygenation) under a NRBM for preoxygenation prior to rapid sequence intubation for respiratory failure.