Novamin infusion: a new method to cure postoperative shivering with hypothermia

Pharmacologic interventions for the therapy of postanesthetic shivering in adults: a systematic review and network meta-analysis

INTRODUCTION

Shivering is a common side effect after general anesthesia. Risk factors are hypothermia, young age and postoperative pain. Severe complications of shivering are rare but can occur due to increased oxygen consumption. Previous systematic reviews are outdated and have summarized the evidence on the topic using only pairwise comparisons. The objective of this manuscript was a quantitative synthesis of evidence on pharmacological interventions to treat postanesthetic shivering.

EVIDENCE ACQUSITION

Systematic review and frequentist network meta-analysis using the R package netmeta. Endpoints were the risk ratio (RR) of persistent shivering at one, five and 10 minutes after treatment with saline/placebo as the comparator. Data were retrieved from Medline, Embase, Central and Web of Science up to January 2022. Eligibility criteria were: randomized, controlled, and blinded trials comparing pharmacological interventions to treat shivering after general anesthesia. Studies on shivering during or after any type of regional anesthesia were excluded as well as sedated patients after cardiac surgery.

EVIDENCE SYNTHESIS

Thirty-two trials were eligible for data synthesis, including 28 pharmacological interventions. The largest network included 1431 patients. The network geometry was two-centered with most comparisons linked to saline/placebo or pethidine. The best interventions were after one minute: doxapram 2 mg/kg, tramadol 2 mg/kg and nefopam 10 mg, after 5 minutes: tramadol 2 mg/kg, nefopam 10 mg and clonidine 150 µg and after 10 minutes: nefopam 10 mg, methylphenidate 20 mg and tramadol 1 mg/kg, all reaching statistical significance. Pethidine 25 mg and clonidine 75 µg also performed well and with statistical significance in all networks.

CONCLUSIONS

Nefopam, tramadol, pethidine and clonidine are the most effective treatments to stop postanesthetic shivering. The efficacy of doxapram is uncertain since different doses showed contradictory effects and the evidence for methylphenidate is based on a single comparison in only one network. Furthermore, both lack data on side effects. Further studies are needed to clarify the efficacy of dexmedetomidine to treat postanesthetic shivering.

Amino acids versus magnesium sulfate infusion for controlling postoperative shivering in patients undergoing percutaneous nephrolithotomy surgery: a randomized clinical trial

BACKGROUND

General anesthetics disrupt the thermoregulatory mechanisms by reducing vasoconstriction and shivering thresholds. Postoperative shivering is a challenging anesthesia-related complication with an incidence range of 20%-70%. Amino acids that induce thermogenesis and magnesium sulfate are centrally acting mechanisms that could minimize shivering. Thus, this trial was designed to compare the effect of amino acid versus magnesium sulfate infusion on postoperative shivering in patients undergoing elective percutaneous nephrolithotomy (PCNL) surgery under general anesthesia.

METHODS

Eighty adults, American Society of Anesthesiologists I and II patients, were randomly assigned into one of two groups. Group A received general anesthesia and perioperative IV amino acid infusion. Group M received general anesthesia and perioperative IV magnesium sulfate infusion.

RESULTS

There was a statistically significant difference in shivering score, which was lower in group A than M (0.8 ± 1.1 versus 1.5 ± 1.3; P-value= 0.01). The incidence of postoperative shivering was lower in group A [4 (10%)] versus [11 (27.5%)] in group M. A less decrease in the core intraoperative temperature (Celsius) was observed in group A than in group M (35.5 ± 0.2 versus 35.1 ± 0.2; respectively, P < 0.001) and at the end of surgery (36.1 ± 0.3 versus 35.7 ± 0.3; respectively, P < 0.001).

CONCLUSIONS

Perioperative amino acids infusion is more effective and better tolerated than magnesium sulfate in preventing postoperative shivering in patients undergoing percutaneous nephrolithotomy surgery. Cost effectiveness should be kept in mind, and amino acids infusion should be reserved in high-risk surgeries for shivering.

Effect of Forced-Air Warming Blanket on Perioperative Hypothermia in Elderly Patients Undergoing Laparoscopic Radical Resection of Colorectal Cancer

The study aimed to evaluate the effect of forced-air warming blanket combined with conventional thermal insulation measures on inadvertent perioperative hypothermia (IPH) in elderly patients undergoing laparoscopic radical resection of colorectal cancer. A total of 70 elderly patients undergoing laparoscopic radical resection of colorectal cancer with general anesthesia were included, and divided into conventional warming treatment (CT) group or forced-air warming treatment (FT) group. In the FT group, based on the conventional warming strategy, patients received prewarming with the forced-air warming blanket (38°C) for ≥20 minutes before induction of anesthesia, and received this treatment continuously during operation. The core body temperature, recovery time from anesthesia, extubating time, and length of stay in the postanesthesia care unit were recorded. The incidence of IPH and postoperative shivering was observed. The incidence of IPH was significantly lower, and average minimum body temperature during the operation was significantly higher in the FT group than that in the CT group (5.7% vs. 22.8% and 36.23°C vs. 35.89°C, respectively). The intraoperative body temperature decreased less (0.32°C vs. 0.69°C), the recovery time from anesthesia was faster (12.8 minutes vs. 17.1 minutes), and the incidence of postoperative shivering was less (2.8% vs. 28.6%) in the FT group than the CT group. In elderly patients undergoing laparoscopic radical resection of colorectal cancer, use of forced-air warming blankets combined with conventional warming measures is more effective to maintain normal body temperature during the perioperative period and reduce the incidence of IPH.

Room Temperature Versus Warm Irrigation Fluid Used for Patients Undergoing Arthroscopic Shoulder Surgery: A Systematic Review and Meta Analysis

PURPOSE

The aim of this study was to analyze whether warm irrigation fluid could reduce postoperative adverse effects in patients undergoing arthroscopic shoulder surgery compared with room temperature irrigation fluid.

DESIGN

A systematic review and meta-analysis of clinical trials was performed.

METHODS

A computerized search of electronic databases was performed. The inclusion criteria were studies comparing the clinical effects of room temperature and warm irrigation fluid on patients undergoing arthroscopic shoulder surgery.

FINDINGS

Warm irrigation fluid reduced the degree of core body temperature drop and the incidence of hypothermia. A statistically lower incidence of shivering also occurred in the warm irrigation fluid group.

CONCLUSIONS

The use of warm irrigation fluid better maintains core body temperature and reduces incidence of shivering than room temperature irrigation fluid. Therefore, warm irrigation fluid is a better choice for arthroscopic shoulder surgery.

Effect of an intraoperative infusion of amino acids on body temperature, serum biochemistry, serum insulin and recovery variables in healthy dogs undergoing ovariohysterectomy

Change in body temperature (BT), serum biochemistry and recovery variables were compared after infusion of amino acids (AA) or lactated Ringer's solution (LRS) in dogs undergoing ovariohysterectomy. Dogs received eight parts 10 per cent AA and two parts LRS (AA, n=10) or only LRS (CG, n=10) at 10 ml/kg/hour during 90 minutes of anaesthesia. BT was measured during anaesthesia and 60 minutes of recovery. Extubation time and shivering were noted. Serum samples were obtained before anaesthesia (T0), end of anaesthesia (T90) and 18 hours after (T18h). Friedman, Mann-Whitney, Kruskal-Wallis or Fisher's exact tests were used for analysis. A decrease in BT of -2.16 (-1.59 to -3.24)°C for group AA and -2.79 (-1.98 to -4.52)°C for group CG was different (P=0.02). Time to extubation was 5 (3-9) minutes for group AA and 9 (5-15) minutes for group CG and was different (P=0.01). Only 30 per cent of dogs in group AA and 100 per cent of dogs in group CG shivered during recovery (P=0.003). Glucose, insulin and blood urea nitrogen at T90 were higher than T0 and T18h for group AA. Dogs receiving intraoperative infusion of AA had a higher BT, extubated sooner and shivered less than control dogs at recovery from anaesthesia.

Efficacy of prophylactic epidural ketamine for reducing shivering in patients undergoing caesarean section with combined spinal-epidural anesthesia

Intravenous ketamine is known to inhibit postoperative shivering; however, at present, there has been little research on whether this effect may be achieved with epidural application. The aim of the present study was to evaluate the efficacy and safety of epidural ketamine as a prophylactic agent to prevent shivering in patients undergoing caesarean section during combined spinal-epidural anesthesia. A prospective, randomized, double-blind study was performed. A total of 60 patients who were undergoing elective caesarean section under combined spinal-epidural anesthesia and had an American Society of Anesthesiologists physical status of I or II were recruited. Patients were randomly allocated to group S (epidural administration of normal saline; n=30) or group K (epidural ketamine 0.5 mg/kg; n=30). An investigator, blinded to the treatment groups, graded postoperative shivering using a 4-point scale and postoperative sedation on a 5-point scale. Operative time, hemodynamic changes and side effects, including hypotension, bradycardia, nausea and hallucinations, were recorded. The results demonstrated that patients' characteristics were not significantly different between groups. Heart rate, peripheral capillary oxygen saturation (SpO₂) values and Apgar scores at 1 and 5 min also did not differ significantly between groups. The incidence and severity of shivering in group K was significantly reduced compared with group S (P<0.05). The mean arterial pressure (MAP) was significantly different in groups S and K compared with baseline values at 10, 30 and 60 min (P<0.05). Furthermore, MAP values at 10, 30 and 60 min were significantly higher in group K compared with in group S (P<0.05). The results of the present study suggest that epidural administration of prophylactic low-dose ketamine may be an effective strategy for preventing postoperative shivering.