Abstract Sat103: Do Capnography Values Differ Between Bag-Valve-Mask Ventilations and Advanced Airways?

Background: Exhaled end-tidal (EtCO 2 ) is widely measured and may indicate the quality of ventilation in out-of-hospital cardiac arrest (OHCA). While EtCO 2 is reliably used after advanced airway placement, it is unknown if bag-valve-mask (BVM) EtCO 2 is similarly measurable and reliable. We sought to determine EtCO 2 differences between BVM and advanced airways during resuscitation from OHCA. Methods: We performed a secondary analysis of data from the Pragmatic Airway Resuscitation Trial (PART), which tested endotracheal intubation or laryngeal tube strategies in OHCA resuscitation. Using previously validated automated signal processing, we identified maximal EtCO 2 values for each ventilation then summarized them into in one-minute(min) epochs. We included all cases with ≥1min EtCO 2 during BVM ventilation. We described BVM EtCO 2 values through medians with interquartile ranges (IQR). We performed a sub-analysis of cases with up to 4min EtCO 2 around advanced airway placement time (2 minutes before and 2 minutes after advanced airway. Using fixed effects models, we compared EtCO 2 during BVM ventilation with values immediately after advanced airway placement. Results: Of the 3004 enrolled in PART, 450 had EtCO 2 recorded during BVM ventilations. A total of 27351 EtCO 2 minutes were captured through PART (advanced airway: 24309min; BVM: 2422min). On average each case had 3 min (IQR: 1-6 min) BVM EtCO 2 recording. EtCO 2 values were variable with median 25 mmHg (IQR:15.4-38.8). In the sub-analysis (Figure 1), EtCO 2 values before and after advanced airway placement were similar with a mean difference 0.48 mmHg (95% CI -2.0 to 1.0, p=0.536, n=235 cases with 774 min EtCO 2 ). Conclusions: Capnography values are detectable during BVM ventilation. BVM EtCO 2 values before and after AA EtCO 2 values appear similar.