The Effect of Preoperative Warming On Reducing Rectal Temperature Drop in Surgical Patients

Lim, Seung Hwa; Cho, Moon Su; Choi, Kyung Sook

Abstract

Although there are many peri-operative measures to reduce core temperature loss during operation, rapid drop has been experienced in the first sixty minutes following induction of general anesthesia. Recently, preoperative warming has been emphasized to prevent inadvertant hypothermia during operation. The purpose of this study is to find the effect of preoperative warming on reducing rectal temperature drop in surgical patients. With informed consent, 46 female adult patients, scheduled for total abdominal hysterectomy or salpingo-oophorectomy in the Seoul National University Hospital from September 3, 1996 to September 19, 1996 were divided into two groups. The variables of age and body surface were matched between the two groups as possible. Among them, 24 patients were preparatively covered up to the shoulders with a forced-air warming blanket(WARM TOUCHTM). set between 36-40degrees C for prewarming, and the other 22 patients(control group)were not before the induction of anesthesia. Rectal temperature was measured by mercury thermometer for rectum after admission to the operating room and by rectal probe which was inserted in the rectum just before the induction during the operation. The rectal temperature was monitored and recorded at every fifteen minutes for the first sixty minutes after the induction and each step during the surgery(intubation, surgical draping, peritoneum opening, one hour and the end of the operation) Collected data were analyzed by means of t-test, Repeated Measures Analysis of Variance with PC-SAS. The results of this study are as following. (1) There was no significant difference between the two groups in age, weight, height, room temperature, basal rectal temperature, operation time. (2) Temperature gradient of the rectal temperature in the warming group was less steeper than that in the control roup during the first sixty minutes after general anesthesia. (3) The rectal temperature measured at every fifteen minutes for the first sixty minutes and the end of surgery after the general anesthesia showed the difference between the two groups during surgery. (4) There was no rectal temperature difference during the intubation, however there was significant temperature difference between the two groups from draping to the end of surgery. In conclusion, prewarming of the surgical patient before induction resulted in increased the skin temperature and heat content, which relieved the dangerous core temperature drop which is potential to be provoked within one hour after induction of the surgical patients and kept the rectal temperature higher than that of the control group during surgery. The suggestions from this study shown below : First, further study is needed to find the preventive effect of the core temperature drop in the first sixth minutes after anesthetic induction by preoperative warming for gastrorectal, thoracic surgery patients who man have the core temperature drop during the operation. Second, in other to keep patient normothermia during the surgery, it needs to study whether using pre-and peri-operative warming can prevent hypothermia or not. Finally, the study of the peroperative warming effect on surgical patients' relaxation and thermal discomfort before the operation is needed because most patients in the case group said to have felt thermal comfort ; 'comfortable' and 'good'.