Abstract
Extracorporeal circulation is performed using hemodiafiltration circuits for the purpose of cooling the core temperatures of patients with severe heat stroke. By using the warmer coil instead of the hemofilter, we thus tried to improve the cooling efficiency even further. We investigated the background, admission status, use of extracorporeal circulation and outcomes in patients with severe heat stroke admitted to our hospital during the period from July 2000 to October 2011. Patients who underwent extracorporeal circulation were divided into two groups: those who underwent extracorporeal circulation before (the previous group) and those who underwent extracorporeal circulation after (the late group) improvements were made to the circuits in 2004. The time from admission until the start of extracorporeal circulation, extracorporeal circulation time, cooling efficiency, period of mechanical ventilation and length of hospitalization were compared between the two groups. Twenty-eight patients were evaluated, and the previous and late groups included six and eight cases, respectively. No significant differences in age, sex, body mass index, APACHE II score, SOFA score, DIC score or core temperature on admission were observed between the two groups. The extracorporeal circulation time was 32.5 minutes in the previous group and 27.5 minutes in the late group. The extracorporeal circulation time decreased in the late group, but no significant differences were observed. Cooling efficiency in the late group was significantly higher than that in the previous group (0.112°C/min vs. 0.040°C/min, p<0.01). No significant differences in the period of mechanical ventilation (6.0 days in the previous group vs. 3.5 days in the late group) or the length of hospitalization (10.0 days in the previous group vs. 13.5 days in the late group) were observed between the two groups. The improvement of cooling efficiency was achieved by devising new circuits and devices. The methods of core temperature cooling that we used in the late period (after 2004) are clinically useful.
