The effects of hypothermia and injury severity on blood loss during trauma laparotomy

To assess the relationships between core temperature (T) and other factors relating to operating room (OR) blood loss and mortality following abdominal injury, the records of 122 patients undergoing laparotomy for trauma at Detroit Receiving Hospital over a 1-year period (1989) were reviewed. Most injuries were penetrating (86%) and the mortality rate was 8.2%. Overall, 57 of 122 (47%) had hypothermia (T < or = 35 degrees C) upon arrival in the OR. There was a significant correlation between admission blood pressure and lowest intraoperative temperature (r = 0.60; p < 0.001). Multiple regression analysis revealed that the patient's lowest temperature (p < 0.001) and Trauma Score (TS); p < 0.0015), but not Abdominal Injury Severity Score (AISS) (p = 0.25) correlated with OR blood loss. The 28 patients with high TS (15 or 16) and AISS > or = 9 had significantly less blood loss when the OR temperature was maintained above 35 degrees C versus 33 degrees-35 degrees C (540 +/- 580 mL vs. 1820 +/- 1160 mL; p < 0.003). This suggests that hypothermia may exacerbate OR blood loss independent of degree of physiologic or anatomic injury. Thus hypothermia is common in patients undergoing a laparotomy for trauma. Trauma scores and the presence of shock preoperatively correlate with the development of intraoperative hypothermia. Hypothermic patients with similar injury severity have greater blood loss. Prevention and rapid correction of hypothermia during resuscitation and surgery appear to be extremely important in reducing blood loss in this patient population.