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[Assessment of factors leading to postanesthetic shivering in patients undergoing laparoscopic colectomy with total intravenous anesthesia using remifentanil].

BACKGROUND
It has been reported that postanesthetic shivering is associated with general anesthesia using remifentanil infusion. The aim of this retrospective study was to evaluate the factors leading to postanesthetic shivering.


METHODS
The patient populations include patients who had undergone laparoscopic colectomy under total intravenous anesthesia with propofol, remifentanil infusion and fentanyl bolus administration. Preoperative clinical variables of interest included age, sex, height, weight, and body surface area. Intraoperative variables of interest included the duration of anesthesia and surgery, pharyngeal temperature at the beginning and the end of the surgery, predicted plasma and effect site concentration of fentanyl at the extubation and mean infusion rate of remifentanil.


RESULTS
The authors identified 53 patients and 9 of them had shown shivering. In shivering group, the duration of anesthesia and surgery was significantly longer, and the predicted plasma and effect site fentanyl concentrations in extubated period were significantly lower. There was no significant difference in either background or core temperature.


CONCLUSIONS
These data suggest that fentanyl concentration may be important for avoiding postanesthetic shivering and the duration of surgery may be a predictor for postanesthetic shivering.