Association between ionized magnesium and postoperative shivering

PURPOSE

Ionized magnesium (iMg) is considered to be the biologically active fraction of circulating total serum Mg (tMg). However, only the relationship between tMg and postoperative shivering has been studied. To our knowledge, hitherto no clinical studies have investigated the association between serum ionized magnesium concentration ([iMg]) and postoperative shivering. Therefore, we aimed to retrospectively examine this association, focusing on hypomagnesemia and depletion of [iMg].

METHODS

This retrospective study involved 421 patients who underwent pancreaticoduodenectomy under general anesthesia at our center from December 2012 to September 2019. Logistic regression analysis was performed to estimate the odds ratio (OR) for the incidence of postoperative shivering.

RESULTS

Postoperative shivering developed in 111 out of 421 patients. The post-surgical concentration of [iMg] was significantly associated with postoperative shivering in the non-adjusted model, but not in the multivariable-adjusted model. In multivariable-adjusted analysis, progressive decrease of [iMg] by 0.1 mmol/L significantly increased the risk of postoperative shivering (OR: 1.64, 95% CI 1.02-2.64, p = 0.04). The multivariable-adjusted OR for postoperative shivering was 3.65 (95% CI 1.25-13.55, p = 0.02) in subjects with post-surgical [iMg] less than 0.6 mmol/L and decrease in [iMg] during surgery compared with those with post-surgical [iMg] more than 0.6 mmol/L and constant or increased of [iMg] during surgery.

CONCLUSION

A decrease in the [iMg] during surgery was significantly associated with postoperative shivering. Subjects who had an [iMg] lower than 0.6 mmol/L post-surgery and decreased [iMg] during surgery had a significantly higher risk of postoperative shivering. Intraoperative depletion of [iMg] was significantly associated with shivering.

Comparison of the effectiveness of dexmedetomidine, meperidine and ketamine in the prevention of postoperative shivering

OBJECTIVE

To compare the prophylactic effectiveness of dexmedetomidine, meperidine, and ketamine for postoperative shivering.

MATERIALS AND METHODS

A randomized, controlled, double-blind, clinical trial, including 160 patients (ASA I - II) undergoing surgical procedures under general anaesthesia for longer than one hour. They were randomly assigned to four groups to receive a single intravenous dose: Dexmedetomidine 1ug/kg (group A, n=33), meperidine 0.4mg/kg (group B, n=38), ketamine 0.5mg/kg (groupC, n=40), or 0.9% saline solution (group D, n=45), administered 20min before the skin suture. To avoid bias, the anaesthetic induction and maintenance technique, as well as postoperative follow-up was standardised.

RESULTS

For any level of shivering, the greatest incidence was observed in the placebo group (47%) (P<.01). The greatest effect on shivering level 3 and 4 occurred in the placebo group (22% and 18%, respectively). For levels 3 and 4 during follow-up, there was not a single case of shivering at any time in the meperidine group (P<.01). The placebo group (38%) had the highest proportion of patients requiring treatment for post-operative shivering (P<.01).

CONCLUSION

Meperidine given intravenously in a single dose of 0.4mg/kg is a useful means for preventing postoperative shivering.

Parecoxib for the prevention of shivering after general anesthesia

BACKGROUND

Shivering is the most common complication during the recovery period after general anesthesia, and there is no clear consensus about the best strategy for its prophylactic. The aim of the study was to evaluate the efficacy of parecoxib in prevention of postoperative shivering.

METHODS

Eighty patients with American Society of Anesthesiologists physical status I-II, who were scheduled for minor urological surgeries under general anesthesia, were randomly assigned to two groups (n = 40 in each group): group P received 40 mg of parecoxib by intravenous bolus injection and group S received the same volume of normal saline in the same way just after the induction of anesthesia. Hemodynamic parameters and body temperatures including tympanic and axillary temperature were monitored. The occurrence of shivering and pain intensity score were recorded during the recovery period.

RESULTS

Parecoxib significantly reduced the incidence and severity of shivering in comparison with the placebo. Postoperative shivering was observed in 22 patients in group S (55%), compared with nine in group P (22.5%) (P = 0.003). In addition, pain intensity scores were lower in group P during recovery period; consequently, less rescue analgesics were required in group P when compared with group S (P = 0.001). Regarding the body temperature, it was found that core temperature decreased but peripheral temperature increased significantly in both groups. There was no significant difference between groups in all time intervals.

CONCLUSIONS

Prophylactic administration of parecoxib produces dual effects on antishivering and postoperative analgesia. This implies that cyclooxygenase 2-prostaglandin E2 pathways may be involved in the regulation of shivering.