Computer simulation of hypothermia during "damage control" laparotomy

"Damage control" is a surgical strategy for the staged repair of severe tra uma that aims to avoid an irreversible physiologic insult marked by a self- propagating combination of hypothermia, coagulopathy, and acidosis. The poi nt beyond which the physiologic insult becomes irreversible, however, remai ns ill-defined. The aim of this study was to address this problem by means of a dynamic computer model of heat loss during laparotomy for exsanguinati ng hemorrhage. A single compartment model was developed using a graphic mod eling tool and was implemented to calculate the time interval from the begi nning of laparotomy to a core temperature of 32 degrees C, which is a marke r of irreversible physiologic derangement in injured patients. A series of simulation runs showed that the exposed peritoneum is the dominant factor c ontributing to heat loss; the bleeding rate has a less marked effect. Eleva tion of the ambient temperature and rapid abdominal closure are effective i nterventions available to the surgeon to modify the heat loss curve. This s tudy shows that during a "damage control" laparotomy for exanguinating hemo rrhage the window of opportunity for salvage before the onset of an irrever sible physiologic insult is no longer than 60 to 90 minutes.