Correlation of Nasal Cannula End-Tidal Carbon Dioxide Concentration With Need for Critical Resources for Blunt Trauma Patients Triaged to Lower-Tier Trauma Activation.

Abstract

Patients assigned lower-tier trauma activation may be undertriaged. Delayed recognition and intervention may adversely affect outcome. For critically injured intubated patients, research shows that abnormally low end-tidal carbon dioxide (EtCO2) values correlate with need for blood transfusion, surgery, and mortality. The purpose of this study was to evaluate EtCO2 monitoring for patients triaged to lower-tier trauma activation. EtCO2 monitoring may aid in the recognition of patients who have greater needs than anticipated. This is a prospective observational study conducted at a Level I trauma center. Potential subjects presenting from the field were identified by lower-tier trauma activation for blunt mechanism. EtCO2 measurements acquired using nasal cannula sidestream technology were prospectively recorded in the trauma bay during the initial assessment. The medical record and trauma registry were queried for demographics, injury data, mortality, and critical resource data defined as intubation, blood transfusion, surgery, intensive care unit admission, and vasoactive medication infusion. EtCO2 data were obtained for 682 subjects during a 10.5-month period. Following exclusions, 262 patients were enrolled for data collection. EtCO2 values less than 30 mmHg were significantly associated with blood transfusion (p = .03) but not with other critical resources or mortality. Although capnography had limited utility for patients triaged to lower-tier trauma activation, EtCO2 values less than 30 mmHg correlated with blood transfusion, consistent with previous studies of critically injured intubated patients. EtCO2 monitoring is noninvasive and may serve as a simple prompt for earlier initiation of blood transfusion, a resource-intensive intervention.