Rewarming following hypothermic cardiovascular surgery:comparison of the use of rewarming mattresses versus prewarmed blankets

The observed incidence of postoperative hypothermia and shivering, following cardiovascular surgery involving cardiopulmonary bypass and induced hypothermia, led to further research of this problem. The ability of postoperative patients to both maintain and/or raise their body temperature to a normal level is hampered by many factors, such as the hypothermic surgery, the anesthesia used, vasoactive medications, etc., during the postoperative period. The stress and work, especially with shivering involved in raising body temperatures, can be detrimental to this group of patients, who have an already compromised cardiopulmonary status. Two methods of re-warming patients were compared to evaluate which method would best facilitate recovery of normal body temperatures and inhibit postoperative shivering. Thirty-one patient subjects randomly assigned to a group were re-warmed by on to two methods. Fifteen (15) patients were placed on a hyperthermia mattress and sixteen (16) patients were covered at varying intervals with pre-warmed blankets. The time necessary to re-warm the patients and the incidence of shivering between groups were compared. Patients actively re-warmed (by the hyperthermia mattress) returned to normal temperatures significantly faster than the group re-warmed with blankets. There was no statistically significant difference in shivering between groups. The results of this study favor the hyperthermia mattress as the preferred method of choice for re-warming hypothermia patients during the early recovery from cardiovascular surgery.