In emergently ventilated trauma patients, low end-tidal CO(2) and low cardiac output are associated and correlate with hemodynamic instability, hemorrhage, abnormal pupils, and death

BACKGROUND: In a smaller experience, the authors previously demonstrated that end-tidal carbon dioxide (PetCO(2)) and cardiac output (CO) had a positive association in emergently intubated trauma patients during Emergency Department resuscitation. The aim of this larger study was to reassess the relationship of PetCO(2) with CO and identify patient risk-conditions influencing PetCO(2) and CO values. METHODS: The investigation consists of acutely injured trauma patients requiring emergency tracheal intubation. The study focuses on the prospective collection of PetCO(2) and noninvasive CO monitor (NICOM®) values in the Emergency Department. RESULTS: From the end of March through August 2011, 73 patients had 318 pairs of PetCO(2) (mm Hg) and CO (L/min.) values. Mean data included Injury Severity Score (ISS) ≥15 in 65.2%, Glasgow Coma Score of 6.4 ± 4.6, hypotension in 19.0%, and death in 34.3%. With PetCO(2) ≤ 25 (15.9 ± 8.0), systolic blood pressure was 77.0 ± 69, CO was 3.2 ± 3.0, cardiac arrest was 60.4%, and mortality was 84.9%. During hypotension, CO was lower with major blood loss (1.9), than without major loss (5.0; P = 0.0008). Low PetCO(2) was associated with low CO (P < 0.0001). Low PetCO(2) was associated (P ≤ 0.0012) with ISS > 20, hypotension, bradycardia, major blood loss, abnormal pupils, cardiac arrest, and death. Low CO was associated (P ≤ 0.0059) with ISS > 20, hypotension, bradycardia, major blood loss, abnormal pupils, cardiac arrest, and death. CONCLUSIONS: During emergency department resuscitation, a decline in PetCO(2) correlates with decreases in noninvasive CO in emergently intubated trauma patients. Decreasing PetCO(2) and declining NICOM CO are associated with hemodynamic instability, hemorrhage, abnormal pupils, and death. The study indicates that NICOM CO values are clinically discriminate and have physiologic validity.