A comparative study on the effects of warm intravenous fluids, intravenous pethidine, and combined warm intravenous fluids and humid-warm oxygen on hemodynamic parameters after general anesthesia in patients with shivering in the recovery room

Introduction: Pethidine is commonly used to treat shivering after general anesthesia (GA), yet respiratory depression may subsequently occur. Warming methods such as warm fluids and/or humid-warm oxygen inhalation can reduce shivering after GA. This randomized clinical trial aimed to compare the effects of three different methods on the reduction of shivering and their hemodynamic and respiratory side-effects in patients undergoing abdominal surgery. Methods: Eighty-seven patients undergoing abdominal surgery by GA were randomly assigned into three groups (two intervention groups versus the pethidine group). Patients in warmed intravenous fluids group received warmed ringer serum (38 °C). The patients in the combined warming group received warmed ringer serum (38 °C) and humid-warm oxygen, and patients in the pethidine group received intravenous pethidine only. The hemodynamic parameters of patients were collected and analyzed. Results: The elapsed time of shivering in the warmed intravenous serum group, the combined warming group and the pethidine group were 7±1.5 min, 6±1.5 min, and 2.8±0.7 min, respectively, where the difference was statistically significant (P<0.05). In the pethidine and combined warming groups, the pulse rate (PR) and systolic blood pressure (SBP) increased, whereas the diastolic blood pressure (DBP) decreased. As for the warmed intravenous serum group, pulse rate, DBP and SBP decreased (P >0.05). The mean respiratory rate (RR) decreased in the pethidine group (from 16 to 15). The mean RR increased (from 16.2 to 16.8) in the combined warming groups, and the differences were statistically significant (p<0.05). Conclusions: The combined warming method reduces the shivering length, while the hemodynamic parameters (PR, BP) remain stable and respiratory depression does not occur. Therefore, it can be used to prevent hypothermia and reduce shivering after general anesthesia.