Impact of total fat mass and skeletal muscle mass index on the occurrence of perioperative hypothermia in Japanese male patients undergoing open gastrectomy: a single institution retrospective cohort study

Abstract Perioperative hypothermia occurs in patients undergoing general anesthesia. Hypothermia is defined as a core body temperature of lower than 36℃. There are few reports on the relationship between patient body composition and occurrence of hypothermia. Therefore, this study was aimed to clarify the relationship between patient body composition and hypothermia. Patients undergoing open gastrectomy were enrolled in the study. Patients whose bladder temperature was lower than 36℃ for more than 1 minute were allocated to the hypothermia group, and the other patients were allocated to the control group. The patient’s body composition was evaluated by the bioelectrical impedance analysis. Of sixty-eight patients enrolled in this study, thirty-four patients were allocated to the hypothermia group. Body surface area per body weight was significantly high in the hypothermia group. Body composition factors such as total fat mass, skeletal muscle mass index, and basal metabolic rate were significantly lower (p < 0.05) in the hypothermia group. Body fat percentage and visceral fat mass were similar between the two groups. Multivariate analysis demonstrated total fat mass less than 11.2 kg (HR 4.51 (95%CI: 1.35–15.03), p = 0.014) and skeletal muscle mass index less than 10.06 kg/m2 (HR 5.61 (95%CI: 1.86–16.93), p = 0.002) as independent risk factors for hypothermia. Low total fat mass and low skeletal muscle mass index will be likely to be risk factors for perioperative hypothermia in open gastrectomy.