Work

Assessment of Preoxygenation using Real-Time End-Tidal Oxygen Measurements Versus Single-Breath End-Tidal Oxygen Measurements in Healthy Volunteers

Year: 2025

Type: article

Abstract: Objective Preoxygenation decreases morbidity for patients requiring endotracheal intubation. However, rigorous means for determining adequate pre-oxygenation are limited in the emergency department (ED). End-tidal oxygenation (EtO 2 ) monitoring could potentially improve preoxygenation in the ED. The accuracy of nasal cannula (NC) EtO 2 in patients receiving supplemental oxygen is unknown. Our study examined the correlation between NC EtO 2 and single-breath (SB) EtO 2 . Methods Healthy volunteers were randomized to receive supplemental oxygen via a nonrebreather mask (NRBM) or a noninvasive ventilation mask (NIV). Participants underwent 3-minute trials at 3 different settings: NRBM at 15 liters per minute (LPM), 35 LPM, and 55 LPM, or NIV at 40% fraction of inspired oxygen (FiO 2 ), 70% FiO 2 , and 100% FiO 2 . NC EtO 2 and SB EtO 2 were obtained at the end of each trial. Results Complete data were obtained for 104 participants. Beta regression analysis revealed a strong correlation between NC EtO 2 and SB EtO 2 in the NIV group (pR 2 = 0.7) and a moderate correlation (pR 2 = 0.4) in the NRBM group. Mean differences in the NRBM arm were 13.1% (15 LPM), 18.0% (35 LPM), 17.1% (55 LPM), and 1.8% (40% FiO 2 ), 5.1% (70% FiO 2 ), and 10.1% (100% FiO 2 ) in the NIV arm. Conclusions Supplemental oxygen led to an overestimation of NC EtO 2 across both groups, with NRBM more than NIV. The correlation between SB EtO 2 and NC EtO 2 suggests NC EtO 2 may be useful in assessing preoxygenation in real-time. Further study is needed to examine its clinical efficacy in preventing desaturation events during endotracheal intubation in the ED.

Source: Journal of the American College of Emergency Physicians Open

DOI: 10.1016/j.acepjo.2025.100079