ABSTRACT
BACKGROUND: In a smaller experience, the authors previously demonstrated that end-tidal carbon dioxide (PetCO2) 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 PetCO2 with CO and identify patient risk-conditions influencing PetCO2 and CO values. METHODS: The investigation consists of acutely injured trauma patients requiring emergency tracheal intubation. The study focuses on the prospective collection of PetCO2 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 PetCO2 (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 PetCO2 ≤ 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 PetCO2 was associated with low CO (P < 0.0001). Low PetCO2 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 PetCO2 correlates with decreases in noninvasive CO in emergently intubated trauma patients. Decreasing PetCO2 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.
ABSTRACT
BACKGROUND: Anoninvasive cardiac output (CO) monitor (NICOM), using Bioreactance technology, has been validated in several nontrauma patient studies. We hypothesized that NICOM CO would have more significant associations with clinical conditions than would systolic blood pressure (sBP). METHODS: This is a prospective observational study of consecutive trauma activation patients during the first 10 to 60 minutes after emergency department arrival. RESULTS: Analysis includes 270 consecutive trauma activation patients with 1,568 observations. CO was decreased (p ≤ 0.002) with major blood loss, hypotension, red blood cell transfusion, Injury Severity Score (ISS) higher than 20, low PetCO2, abnormal pupils, elderly, preexisting conditions, low body surface area level, females, hypothermia, and death. CO was increased (p < 0.0001) with base deficit, ethanol positivity, and illicit drug positivity. The sBP was decreased (p ≤ 0.0005) with major blood loss, red blood cell transfusion, low PetCO2, low body surface area level, and illicit drug positivity. The sBP was increased (p e 0.01) with ISS higher than 20, elderly, and preexisting conditions. Total significant condition associations were CO 83% (15 of 18 patients) and sBP 47% (8 of 17 patients; p = 0.03). In hypotensive patients, CO was lower with major blood loss (3.3 ± 2.1 L/ min) than without (6.0 ± 2.2 L/min; p < 0.0001). Of survivors with ISS 15 or higher, NICOM patients experienced a shorter hospital length of stay (10.5 days) when compared with 2009 and 2010 patients (14.0 days; p = 0.03). CONCLUSION: The multiple associations of CO with patient conditions imply that NICOM provides an objective and clinically valid, relevant, and discriminate measure of cardiac function in acutely injured trauma activation patients. NICOM use may be associated with a shorter length of stay in surviving patients with complex injuries.
