Advanced Airway Devices and End-Tidal Capnography Trends in Cardiac Arrest: A Secondary Analysis of a Randomized...

While variable advanced airway devices are used in out-of-hospital cardiac arrest (OHCA) resuscitation, potential differences in ventilation metrics are not well known.

To characterize differences in end-tidal carbon dioxide (EtCO2) capnography trajectories between laryngeal tube (LT) and endotracheal intubation (ETI) during OHCA.

This secondary analysis of EtCO2 capnography waveforms from the Pragmatic Airway Resuscitation Trial (PART), a multicenter cluster-crossover randomized clinical trial, was performed November 1, 2023, through July 8, 2025. Participants in this analysis were adults (aged ≥18 years) with nontraumatic OHCA from 27 emergency medical services (EMS) agencies, which were placed into 13 clusters. Participants were assigned to LT or ETI airway management. All cases with 50% or greater interpretable EtCO2 signal were included.

LT vs ETI airway management.

Mean maximal EtCO2 values within 1-minute epochs and trends over resuscitation after LT or ETI. Associations with OHCA outcomes were also evaluated, including sustained return of spontaneous circulation (ROSC) and 72-hour survival. Using the Mann-Whitney test, EtCO2 of LT and ETI cases were compared at 20-, 10-, and 1-minute resuscitation. EtCO2 trends over time were evaluated using Cochran-Armitage test of trend. Covariates in multivariable logistic regression models for outcomes were adjusted, including interaction between advanced airway device and EtCO2 trends.

Of the 3004 cases in PART, 1113 (818 in LT and 295 in ETI groups) had available EtCO2 data and were included in the secondary analysis. Patients were mostly male (694 [62.4%]), had a median (IQR) age of 64 (52-75) years, and had a nonshockable (941 [84.6%]), nonpublic (999 [89.8%]) OHCA. ROSC occurred in 144 patients (17.6%) receiving LT and 54 (18.3%) receiving ETI. EtCO2 values did not differ between LT and ETI groups (20-minute resuscitation: 33.9 vs 29.4 mm Hg, P = .07; 10-minute resuscitation: 30.9 vs 28.5 mm Hg, P = .89; 1-minute resuscitation: 32.2 vs 28.3 mm Hg, P = .28). In ROSC compared with non-ROSC cases, patients in LT (27.9 to 52.3 mm Hg vs 32.6 to 23.5 mm Hg; P < .001) and ETI (38.2 to 46.7 mm Hg vs 27.7 to 20.0 mm Hg; P < .001) groups exhibited increasing EtCO2 during resuscitation. EtCO2 trend and advanced airway interaction was associated with ROSC (odds ratio [OR], 1.75; 95% CI, 1.25-2.45) but not survival (OR, 1.21; 95% CI, 0.90-1.61). Therefore, we performed an advanced airway stratified analysis for ROSC (ETI: OR, 2.34 [95% CI, 1.67-3.26]; LT: OR, 1.33 [95% CI, 1.20-1.47]).

In this secondary analysis of PART, EtCO2 values did not differ between LT and ETI. However, due to significant interaction between advanced airway device and EtCO2 trends, individual interpretation of these parameters may not be accurate.