Ventilation Rates and Capnography in Pediatric Out-of-Hospital Cardiac Arrest with Advanced Airways

Ventilation is important in out-of-hospital cardiac arrest resuscitation; however, few studies describe ventilation rates during pediatric out-of-hospital cardiac arrest (pOHCA). Our objective was to characterize ventilations and end-tidal capnography (EtCO₂) after advanced airway placement by emergency medical services (EMS) during pOHCA resuscitation.

This was a retrospective cohort study that included pediatric (age < 18 years) non-traumatic OHCA treated by an urban fire-based EMS system (Columbus Division of Fire, Columbus, Ohio) from April 2019 to December 2020. We identified ventilations delivered during resuscitation by manual review of continuous EtCO₂ recorded by cardiac monitors. We also identified ventilations using automated detection algorithms previously validated in adult resuscitation. Mean ventilation rate and EtCO₂ were summarized in one-minute (min) epochs from advanced airway insertion through end of resuscitation efforts. We compared return of spontaneous circulation (ROSC) vs non-ROSC ventilation rates using Student's t-tests. Cochran-Armitage test of trend was used to evaluate EtCO₂ temporal trends. Associations between ROSC and EtCO₂ were tested using a regression model.

We identified 38 pOHCA cases and 30 cases were included for ventilation analysis. Cases were primarily infants (0.7 years, IQR 0.17-2), male (52.6%), and African-American race (63.1%). Most pOHCAs were unwitnessed (65.8%) with non-shockable rhythms (94.8%) and infrequent bystander cardiopulmonary resuscitation (31.2%). Eight patients achieved ROSC (21.2%) and two patients survived (5.3%). Advanced airway attempts included supraglottic airway devices (71.1%), endotracheal intubation (7.8%), or both (7.8%). Ventilation rates ranged from 0-23 per minute. Automated ventilation detection algorithms performed well in pediatric ventilation detection where the mean standard error was 3.7 mmHg in EtCO₂ values and 1.3 per minute in ventilation rates. Ventilation rates differed between ROSC and non-ROSC groups (9.2 vs 6.9 per min, p < 0.001). Ranges of EtCO₂ values included 0-100 mmHg during resuscitation. The EtCO₂ trends over time differed between ROSC and non-ROSC groups (59.82 mmHg to 75.9 mmHg vs 20.7 mmHg to 19.0 mmHg, p < 0.01). EtCO₂ was significantly associated with ROSC (OR 1.0 95% CI 1.00-1.01, p < 0.001).

These results offer one of the first perspectives of ventilation in pOHCA. Differences were observed in ventilation rates and EtCO₂ trends between ROSC and non-ROSC cases.