Sublingual Capnometry for Rapid Determination of the Severity of Hemorrhagic Shock

Abstract

Sublingual capnometry (SLCO2) is a rapid, minimally invasive bedside test of focal tissue perfusion. We hypothesized that SLCO2 could diagnose hemorrhagic shock and monitor adequacy of resuscitation. We compared the ability of SLCO2, serum lactate (LAC), and base deficit (BD) to predict outcome in hypotensive trauma patients. Prospective, observational trial at two Level I trauma centers was performed. Inclusion criteria were blunt or penetrating trauma patients, age > or =16 years, with hypotension (systolic blood pressure < or =90 mm Hg). SLCO2, LAC, and BD were measured in each patient at admission, at the end of active hemorrhage, and at 6, 24, and 48 hours. Data are reported as means (+/-SD). A total of 86 patients were enrolled: mean age 35 (+/-17) years, 80% male, 51% blunt trauma, Injury Severity Score score 20 (+/-14). Twenty patients died. SLCO2 at admission was 52.4 (+/-13.3) in survivors versus 87.9 (+/-35.6) in nonsurvivors (p < 0.001). Receiver operating characteristic (ROC) curves showed that SLCO2, LAC, and BD were all good predictors of mortality. The area under each ROC curve was as follows: SLCO2 (0.82; 95% CI 0.70-0.96; p < 0.001), LAC (0.80; 95% CI 0.69-0.91; p < 0.001), BD (0.87; 95% CI 0.77-0.98; p < 0.001). There was no significant difference (p > 0.05) in the areas under the three curves. SLCO2 predicted survival in hypotensive trauma patients. It had equivalent diagnostic ability to LAC and BD. This rapid test may supplement standard, more invasive measures of hemorrhagic shock.