ABSTRACT
BACKGROUND: Simultaneous use of nasal cannula (NC) with noninvasive positive pressure ventilation (NIPPV) may help streamline the transition from preoxygenation to intubation with apneic oxygenation in patients with deteriorating respiratory status, but may also compromise preoxygenation by impairing NIPPV mask seal. OBJECTIVES: To demonstrate that end-tidal oxygen (EtO2) after NIPPV with NC is noninferior to that of NIPPV without NC. METHODS: We conducted a randomized cross-over noninferiority study using healthy volunteers. All subjects underwent a 3-min trial of NIPPV with or without high-flow NC at 15 L/min of oxygen, followed by a 5-min washout period, and then a second 3-min trial of the opposite intervention. We randomized subjects to order of interventions. The primary outcome was postintervention EtO2 as measured by immediate exhalation into an oxygen analyzer after the 3-min ventilation period. We compared this outcome between the two study arms using an absolute 5% noninferiority margin. RESULTS: We enrolled 37 subjects, each of whom underwent both interventions of NIPPV alone and NIPPV with 15 L/min NC. The paired mean difference in EtO2 between NIPPV with NC measurements vs. NC alone measurements was 0.5% (95% confidence interval -∞ to 2.7%). Analyses stratified by order of intervention yielded similar results. CONCLUSIONS: The mean difference confidence interval did not include the noninferiority margin. Hence, NIPPV with NC seems noninferior to NIPPV alone with regard to EtO2. These results indicate that concomitant use of NC with NIPPV may be an appropriate preoxygenation strategy in anticipation of the potential need for transition to intubation.
Subject(s)
Cannula , Noninvasive Ventilation/standards , Tidal Volume/physiology , Adult , Cross-Over Studies , Female , Healthy Volunteers , Humans , Male , Noninvasive Ventilation/methods , Oximetry/methods , Oximetry/statistics & numerical data , Oxygen Inhalation Therapy/methods , Oxygen Inhalation Therapy/standards , Prospective StudiesSubject(s)
Cannula , Noninvasive Ventilation , Intubation, Intratracheal , Oxygen , Positive-Pressure RespirationABSTRACT
BACKGROUND: Nasal cannula can achieve apneic oxygenation during emergency intubation. However, pre-procedure nasal cannula placement may be difficult in patients undergoing non-invasive positive pressure ventilation (NPPV) prior to intubation. Our objective was to compare mask leak during NPPV with versus without simultaneous application of nasal cannula. We hypothesized mask leak would be no worse with concomitant use of nasal cannula (non-inferiority design). METHODS: We performed a randomized crossover non-inferiority study of healthy volunteers. We randomized subjects undergoing 60s trials of NPPV (10cmH2O continuous positive airway pressure) to either NPPV alone (NPPV-a) or NPPV with nasal cannula at 15L/min (NPPV-nc). After a brief rest period, all subjects underwent the alternative intervention. The primary outcome was time averaged mask leak over 60s (L/min). We defined a non-inferiority margin of 5L/min. RESULTS: We enrolled 64 subjects. Mean time-averaged mask leak was 2.2L/min for NPPV-a versus 4.0L/min for NPPV-nc for a difference of 1.7L/min (one-sided 95% CI -∞ to 3.2L/min). NPPV-a resulted in higher mean minute volume received (13.5 versus 12.2L) and higher mean respiratory rates (14.8 versus 13.5 breaths per minute). CONCLUSION: The addition of nasal cannula during NPPV does not significantly increase mask leak. The simultaneous application of nasal cannula with NPPV may be a useful strategy to streamline airway management among patients undergoing NPPV prior to intubation.
