Nefopam or clonidine in the pharmacologic prevention of shivering in patients undergoing conscious sedation for interventional neuroradiology

Comparative effectiveness of pharmacologic interventions to prevent shivering after surgery: a network meta-analysis

INTRODUCTION

Although many drugs have been studied to prevent postoperative shivering, their comparative effectiveness is unknown. We attempted to assess the comparative effectiveness of the pharmacologic strategies to prevent shivering after surgery including intravenous (IV) and intrathecal (IT) meperidine, IV and IT dexmedetomidine, IV and IT clonidine, nefopam, tramadol, ketamine, and serotonin receptor antagonists.

EVIDENCE ACQUISITION

We implemented a frequentist network meta-analysis of randomized trials. Random effect model was selected according to deviance information criteria. The incidence of moderate or severe shivering and the overall incidence of postoperative shivering were compared in all patients and subgroups of general and spinal anesthesia.

EVIDENCE SYNTHESIS

Seventy trials with 6062 participants were included. All interventions except clonidine IT and dexmedetomidine IT significantly decreased the incidence of moderate or severe shivering. All interventions except clonidine IT significantly decreased the overall incidence of shivering. Nefopam IV was ranked best regarding both the incidence of moderate or severe shivering (odds ratio [OR] 0.04, 95% confidence interval [CI] 0.04-0.25, SUCRA 86.2, moderate quality-evidence), and the overall incidence of shivering (OR 0.07, 95% CI 0.03 to 0.15, SUCRA 85.7, moderate quality-evidence), which was consistent in the subgroups of anesthesia.

CONCLUSIONS

Nefopam was ranked best regarding both severity and incidence of postoperative shivering. In addition to nefopam, tramadol, meperidine IV and IT, and dexmedetomidine IV were ranked high. However, there was significant heterogeneity regarding the individual drug regimen and surgery type, precluding firm conclusion. Further randomized trials are required to compare the efficacy of the drugs with high rank.

Nefopam for the prevention of perioperative shivering: a meta-analysis of randomized controlled trials

BACKGROUND

Shivering is a frequent complication following surgery and anaesthesia. A large variety of studies have been reported that nefopam may be efficacious for the prevention and treatment of perioperative shivering. Regrettably, there is still no conclusion of the efficacy and safety of nefopam for the prevention of perioperative shivering. The aim of this analysis is to evaluate the efficacy of nefopam for the prevention of perioperative shivering in patients undergoing different types of anaesthesia compared with placebo group and other active interventions.

METHODS

PubMed, EMBASE, Cochrane Central Register of Control Trials were systematically searched for potentially relevant trials. Trial quality and extracted data were evaluated by two authors independently. Dichotomous data on the absence of shivering was extracted and analysed by using relative risk (RR) with 95% confidence interval (CI). Continuous outcome was abstracted and analysed by using weighted mean difference (WMD) with 95% confidence interval (CI). Outcome data was analysed by using random effect model or fixed effect model in accordance with heterogeneity.

RESULTS

Compared with placebo, prophylactic administration of nefopam significantly reduced the risk of perioperative shivering not only in the patients under general anaesthesia but also neuraxial anaesthesia (RR 0.08; 95% CI 0.05-0.13). As compared with clonidine, nefopam was more efficacious in the prevention of perioperative shivering (RR 0.34; 95% CI 0.17-0.70). Nefopam has no influence on the extubation time (WMD 0.92; 95% CI -0.15-1.99).

CONCLUSION

Our analysis has demonstrated that nefopam is associated with the decrease of risk of perioperative shivering following anaesthesia without influencing the extubation time.

Whole body cooling in newborn infants with perinatal asphyxial encephalopathy in a low resource setting: a feasibility trial

OBJECTIVE

To determine the feasibility and safety of whole body cooling in newborn infants with perinatal asphyxial encephalopathy in a low resource setting.

DESIGN

Feasibility trial.

SETTING

Tertiary care perinatal centre.

SUBJECTS

Infants born at > 35 weeks gestation with perinatal asphyxia were included in the study.

INTERVENTIONS

Infants were cooled to a rectal temperature of 33 ± 0.5°C for 72 hours using cloth-covered ice-gel packs. Vital parameters were monitored continuously.

OUTCOME MEASURES

The primary outcome was the achievement of target temperature within 1 hour of initiation of treatment and maintaining the target temperature for 72 hours. Adverse events and possible complications of hypothermia were the secondary outcomes measured.

RESULTS

Twenty infants were included in the study. The mean time taken to achieve target rectal temperature was 52 ± 25 minutes. The mean rectal temperature during cooling was 32.9 ± 0.11ºC. The target temperature could be maintained for 72 hours without difficulty in all babies. Adverse events observed during cooling were thrombocytopenia (25%), sinus bradycardia (25%), deranged bleeding parameters (20%), aposteatonecrosis (15%), hyperglycemia (15%), hypoglycemia (10%), hypoxemia (5%), life-threatening coagulopathy (5%) and death (5%). Shivering was noted in many of the babies, especially in the initial phase of cooling.

CONCLUSION

Whole body cooling in term infants with perinatal asphyxia is achievable, safe and inexpensive in a low-resource setting.

Induced hypothermia for infants with hypoxic- ischemic encephalopathy using a servo-controlled fan: an exploratory pilot study

OBJECTIVE

Several trials suggest that hypothermia is beneficial in selected infants with hypoxic-ischemic encephalopathy. However, the cooling methods used required repeated interventions and were either expensive or reported significant temperature variation. The objective of this pilot study was to describe the use, efficacy, and physiologic impact of an inexpensive servo-controlled cooling fan blowing room-temperature air.

PATIENTS AND METHODS

A servo-controlled fan was manufactured and used to cool 10 infants with hypoxic-ischemic encephalopathy to a rectal temperature of 33 degrees C to 34 degrees C. The infants were sedated with phenobarbital, but clonidine was administered to some infants if shivering or discomfort occurred. A servo-controlled radiant warmer was used simultaneously with the fan to prevent overcooling. The settings used on the fan and radiant warmer differed slightly between some infants as the technique evolved.

RESULTS

A rectal temperature of 34 degrees C was achieved in a median time of 58 minutes. Overcooling did not occur, and the mean temperature during cooling was 33.6 degrees C +/- 0.2 degrees C. Inspired oxygen requirements increased in 6 infants, and 5 infants required inotropic support during cooling, but this was progressively reduced after 1 to 2 days. Dehydration did not occur. Five infants shivered when faster fan speeds were used, but 4 of the 5 infants had hypomagnesemia. Shivering was controlled with clonidine in 4 infants, but 1 infant required morphine.

CONCLUSIONS

Servo-controlled fan cooling with room-temperature air, combined with servo-controlled radiant warming, was an effective, simple, and safe method of inducing and maintaining rectal temperatures of 33 degrees C to 34 degrees C in sedated infants with hypoxic-ischemic encephalopathy. After induction of hypothermia, a low fan speed facilitated accurate temperature control, and warmer-controlled rewarming at 0.2 degrees C increments every 30 minutes resulted in more appropriate rewarming than when 0.5 degrees C increments every hour were used.

Thermoregulatory management for mild therapeutic hypothermia

In recent years the use of mild therapeutic hypothermia as a means of neuroprotection has become an important concept for treatment after cerebral ischemic hypoxic injury. Mild therapeutic hypothermia has been shown to improve outcome after out-of-hospital cardiac arrest, and many studies suggest a beneficial effect of mild therapeutic hypothermia on patient outcome after traumatic brain injury, cerebrovascular damage and neonatal asphyxia. This review article explores the numerous possibilities and methods for the induction of mild therapeutic hypothermia, reviews thermoregulatory management during maintenance and discusses associated risks and complications.

The effect of intensive insulin therapy on infection rate, vasospasm, neurologic outcome, and mortality in neurointensive care unit after intracranial aneurysm clipping in patients with acute subarachnoid hemorrhage: a randomized prospective pilot trial

It is unclear if avoiding hyperglycemia during intensive care after acute brain injury improves morbidity, mortality, and neurologic outcome. This prospective randomized trial tested whether intensive insulin therapy affected infection rates, vasospasm, mortality, or long-term neurologic outcome in subarachnoid hemorrhage patients during their intensive care unit (ICU) stay. Comparison was made against conventional insulin therapy using a randomized trial design. The primary outcome measure was infection rate until the fourteenth postoperative day in the ICU or until patient discharge. Secondary end points were the incidence of vasospasm until the fourteenth postoperative day in the ICU or until patient discharge, and neurologic outcome and mortality at 6 months follow-up. A total of 78 patients were prospectively enrolled and randomly assigned either to conventional insulin therapy or to intensive insulin therapy (38 and 40 patients, respectively). The infection rate during the study was significantly higher in patients who received conventional insulin therapy than in patients who received intensive insulin therapy (42% vs. 27%; P<0.001). The incidence of vasospasm during the study was also similar in conventional and intensive therapy groups (31.5% vs. 27.6% in the conventional and intensive insulin therapy groups; P=0.9). Overall mortality rates at 6 months were similar in the 2 groups (18% vs.15%; P=0.9), as was the neurologic outcome at 6 months [modified Rankin score >3 in 22/38 patients (57.8%) in the conventional therapy group vs. 21/40 patients (52.5%) in the intensive insulin therapy group; P=0.7]. Intensive insulin therapy in patients with acute subarachnoid hemorrhage admitted to a postoperative neurosurgical ICU after surgical clipping of intracranial aneurysms decreases infection rates. The benefit of strict glycemic control on postoperative vasospasm, neurologic outcome, and mortality rates does not seem to be affected by intensive insulin therapy.

Progress in shivering control

Hypothermia is a potent neuroprotectant and induced hypothermia holds great promise as a therapy for acute neuronal injury. Thermoregulatory responses, most notably shivering, present major obstacles to therapeutic temperature management. A review of thermoregulatory physiology and strategies aimed at controlling physiologic responses to hypothermia is presented.