The effect of an intravenous injection of branched chain amino acids on body temperature of cats undergoing general anesthesia.

Abstract

Perioperative hypothermia is a common complication in anesthetized cats. Nutrient induced thermogenesis (NIT) with intravenous administration of amino acids (AAs) is a technique used to increase endogenous heat production, which attenuates heat loss during general anesthesia. Branched chain amino acids (BCAAs) may be more effective than other AAs for NIT. The hypothesis tested was that cats receiving a single intravenous injection of BCAAs at 100 or 200 mg/kg prior to general anesthesia will have a body temperature at least 0.5℃ higher than cats receiving an injection of lactated ringer’s solution (LRS). Ten research cats underwent general anesthesia three times with three different treatments; 3 ml/kg LRS, 100mg/kg BCAA (B100), or 200mg/kg BCAA (B200) solution immediately prior to induction of anesthesia. After induction, rectal and thoracic skin temperature were measured every 5 and 15 minutes with a temperature probe and thermograms, respectively. Blood samples were collected for the measurement of blood urea nitrogen (BUN), creatinine (Cre), glucose (BG) and plasma insulin (insulin) concentrations just prior to induction, at the end of the 90 minute period of anesthesia, and 24 hours after anesthesia induction. The differences between baseline and each time point on rectal (ΔTr) and thoracic skin (ΔTt) temperature during anesthesia were calculated. The trapezoid method was used for the calculation of AUC for ΔTr and ΔTt. The differences between baseline and each sampling point for BUN (ΔBUN), Cre (ΔCre), BG (ΔBG) and insulin (Δinsulin) were calculated. The normality of data was tested by D’Agositno-Pearson test. Parametric or non-parametric data were analyzed by one-way repeated measures ANOVA with Tukey post-hoc test or Friedman test and Dunn’s post hoc test. A value of p < 0.05 was set for significance. There was no significant difference in AUC of ΔTr and ΔTt during anesthesia (p = 0.3675 and 0.9737, respectively). ΔBUN, ΔCre, ΔBG and Δinsulin did not differ between groups for any time points. However, the incidence of hypoglycemia after anesthesia tended to be higher in both B100 and B200 groups than those of LRS group. BCAAs-NIT did not reduce heat loss during anesthesia while likely to increase the risk of perioperative hypoglycemia in cats.