Pharmacological Treatment of Postoperative Shivering: A Quantitative Systematic Review of Randomized Controlled Trials

A Comparison between Intrathecal Nalbuphine and Fentanyl for Intraoperative Pain Management during Uterine Exteriorization in Cesarean Section: A Randomized Controlled Trial

BACKGROUND: Uterine exteriorization during cesarean section is linked to an increased incidence of visceral pain. AIM: This study explored the ability of intrathecal nalbuphine to alleviate this accompanied pain to be used as an effective safer alternative to fentanyl, as there is almost no study compared between these agents to alleviate visceral pain induced by uterine exteriorization. METHODS: This double-blinded randomized controlled research was done on 135 cases subjected to cesarean section with exteriorization of the uterus. Patients were randomized equally into F, N, and C groups which received 25 μg fentanyl, 800 μg nalbuphine, and 0.5 ml saline, respectively, added to intrathecal 0.5% hyperbaric bupivacaine. The occurrence of visceral and shoulder pain and their VAS, the need for rescue IV fentanyl, adverse events, hemodynamics, and Apgar scores were evaluated. RESULTS: The incidence of visceral pain was 22.2%, 24.4%, and 66.7% for Groups F, N, and C, respectively. Patients who needed rescue IV fentanyl were 6.7%, 11.1%, and 60% for Groups F, N, and C, respectively. The statistical difference regarding these parameters was highly significant (p < 0.0001) between C group and both F and N groups but insignificant between F and N groups. Nausea, shivering, itching, and bradycardia were significantly lower (p < 0.05) in N group in comparison to F and C. HR had a significant difference between F group and both N and C groups. CONCLUSION: Intrathecal nalbuphine is an effective safer alternative to fentanyl to control visceral pain induced by uterine exteriorization during cesarean delivery.

The effects of a forced-air warming system plus electric blanket for elderly patients undergoing transurethral resection of the prostate: A randomized controlled trial

BACKGROUND

Perioperative inadvertent hypothermia in elderly urology patients undergoing transurethral resection of the prostate (TURP) is a well-known serious complication, as it increases the risk of myocardial ischemia, blood loss, and surgical wound infection. We conducted this prospective randomized controlled trial to evaluate the combined effect of a forced-air warming system and electric blanket in elderly TURP patients.

METHODS

Between January 2015 and October 2017, we recruited 443 elderly male patients undergoing elective TURP with subarachnoid blockade (SAB). These were randomly divided into 3 groups: group E (intraoperative warming using electric blankets set to 38°C; n = 128); group F (intraoperative warming using a forced-air warmer set to 38°C; n = 155) and group FE (intraoperative warming using a forced-air warmer plus electric blankets, both set to 38°C; n = 160). The primary outcome was shivering and their grades. Hemodynamic changes, esophageal temperature, recovery time, incidences of adverse effects, and patient and surgeon satisfaction were also recorded.

RESULTS

Baseline characteristics showed no significant differences when compared across the 3 groups (P >.05). Compared with groups E and F, both HR and mean arterial pressure (MAP) in group FE were significantly decreased from T6 to T10 (P <.05). Compared with groups E and F, esophageal temperature in group FE increased significantly from T5 to T10 (P <.05). Compared with group E, esophageal temperature in group F was significantly increased from T5 to T10 (P <.05). Compared with groups F and FE, post-anesthesia care unit (PACU) recovery time was longer in group E, while compared with group F, PACU recovery time was shorter in group FE (P <.05). Compared to patients in groups E and F, those in group FE had a significantly lower incidence of arrhythmia and shivering (P <.05). The number of patients with shivering grades 0 to 3 was higher in group E than in other groups, while the number of patients with shivering grade 2 was significantly higher in group F than in group FE (P <.05). Patient and surgeon satisfaction scores were higher in group FE than in groups E and F (P <.05).

CONCLUSIONS

Use of a forced-air warming system combined with an electric blanket was an effective method with which to retain warmth among elderly TURP patients.

Preventing shivering with adjuvant low dose intrathecal meperidine: A meta-analysis of randomized controlled trials with trial sequential analysis

The aim of this systematic review and meta-analysis is to evaluate the pros and cons of adjuvant low dose intrathecal meperidine for spinal anaesthesia. We searched electronic databases for randomized controlled trials using trial sequential analysis (TSA) to evaluate the incidence of reduced rescue analgesics, shivering, pruritus, nausea and vomiting when applying adjuvant intrathecal meperidine. Twenty-eight trials with 2216 patients were included. Adjuvant intrathecal meperidine, 0.05-0.5 mg kg-1, significantly reduced incidence of shivering (relative risk, RR, 0.31, 95% confidence interval, CI, 0.24 to 0.40; TSA-adjusted RR, 0.32, 95% CI, 0.25 to 0.41). Intrathecal meperidine also effectively reduced need for intraoperative rescue analgesics (RR, 0.27, 95% CI, 0.12 to 0.64; TSA-adjusted RR, 0.27, 95% CI, 0.08 to 0.91) and the incidence of pruritus was unaffected (RR, 2.31, 95% CI, 0.94 to 5.70; TSA-adjusted RR, 1.42, 95% CI, 0.87 to 2.34). However, nausea and vomiting increased (RR, 1.84, 95% CI, 1.29 to 2.64; TSA-adjusted RR, 1.72, 95% CI, 1.33 to 2.23; RR, 2.23, 95% CI, 1.23 to 4.02; TSA-adjusted RR,1.96, 95% CI, 1.20 to 3.21). Under TSA, these results provided a sufficient level of evidence. In conclusion, adjuvant low dose intrathecal meperidine effectively attenuates spinal anaesthesia-associated shivering and reduces rescue analgesics with residual concerns for the nausea and vomiting.

A Clinical Trial of the Effect of Warm Intravenous Fluids on Core Temperature and Shivering in Patients Undergoing Abdominal Surgery

PURPOSE

This study was conducted to investigate the effect of warm intravenous fluids on shivering and core temperature of patients undergoing abdominal surgery.

DESIGN

This study was a two-group clinical-control trial.

METHODS

Ringer's solution at normal room temperature and serum at 38°C were infused in the control and intervention groups, respectively. Shivering, core temperature, SpO₂, and vital signs were measured at admission to the operating room and postanesthesia care unit (PACU) and 30 minutes after the admission to the PACU.

FINDINGS

There was a significant difference between the two groups in terms of shivering, core temperature, and pulse rate at the time of admission to the PACU and 30 minutes after.

CONCLUSIONS

Ringer's solution at 38°C instead of room temperature can be used to reduce the incidence of postanesthetic hypothermia and shivering in patients undergoing abdominal surgery. Using this method in addition to other nursing care is recommended preoperatively.

Dexmedetomidine as a neuraxial adjuvant for prevention of perioperative shivering: Meta-analysis of randomized controlled trials

BACKGROUND

Dexmedetomidine, a highly selective α2-adrenoceptor agonist, has been investigated for anti-shivering effects in some trials. This current meta-analysis was conducted to evaluate the effectiveness of dexmedetomidine as a neuraxial adjuvant in preventing perioperative shivering.

METHODS

This systematic review and meta-analysis was registered in PROSPERO [www.crd.york.ac.uk/PROSPERO] with the unique identification number CRD42017055991. The electronic databases PubMed, Embase, Cochrane Central Register of Controlled Trials (CENTRAL) were searched to select high-quality randomized controlled trials (RCTs) that evaluated the anti-shivering efficacy for neuraxial application dexmedetomidine as local anesthetic adjuvant. Effects were summarized using pooled risk ratios (RRs), weighed mean differences (MDs), or standardized mean differences (SMDs) and corresponding 95% confidence intervals (Cls) with random effect model. Heterogeneity assessment, sensitivity analysis, and publication bias were performed. The primary outcome was perioperative shivering.

RESULTS

A total of 1760 patients from 24 studies were included in this meta-analysis. Compared with the placebo, dexmedetomidine reduced the incidence of perioperative shivering (RR: 0.34; 95% Cl: 0.21 to 0.55; P < 0.00001), with a maximum effective dose of 5μg via subarachnoid space injection (RR: 0.55; 95% CI: 0.32 to 0.92; P = 0.02), especially in cesarean section (RR: 0.20; 95% CI: 0.09 to 0.45; P = 0.0001). Dexmedetomidine also could improve the characteristics of the block, with an increase only in the incidence of bradycardia (RR: 2.11; 95% CI: 1.23 to 3.60; P = 0.006). No significant difference could be found compared dexmedetomidine with other adjuvants, except morphine.

CONCLUSIONS

This meta-analysis shows that dexmedetomidine as a neuraxial adjuvant had statistically significant efficacy on prevention of perioperative shivering. Moreover, dexmedetomidine could improve the characteristics of the block. However, the potential induction of bradycardia should be taken seriously.

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.

Prevalence, associated factors and treatment of post spinal shivering in a Sub-Saharan tertiary hospital: a prospective observational study

Background

Surgery and anaesthesia cause shivering due to thermal dysregulation as a compensatory mechanism and is worsened by vasodilatation from spinal anaesthesia that redistributes core body heat. Due to paucity of data Mulago Hospital’s post spinal shivering burden is unknown yet it causes discomfort and morbidity.

Methods

Ethical approval was obtained to perform the study among consenting mothers due for elective caesarean section from March to May 2011. We recruited ASA class I & II parturients and excluded non-consenting or spinal contra-indication patients. A standard spinal anaesthetic of 2mls of 0.5 % bupivacaine was given, intraoperative vitals were recorded every 5 min and we monitored for perioperative shivering till PACU discharge.

Results

We recruited 270 patients with majority being emergency caesarean deliveries (90.74 %), mainly due to failed progress from cephalopelvic disproportion. We noted 8.15 % shivering occuring mostly at 20 min, with hypotension plus hypothermia as associated factors. Intravenous pethidine (Meperidine) 25 mg effectively treated shivering and we had drowsiness, nausea and vomiting as PACU side effects that resolved on discharge to the ward.

Conclusion

Post spinal shivering had a prevalence of 8.15 %, commonly occurred at 20 min postoperatively with hypotension plus hypothermia as main associated factors and intravenous Pethidine controlled it.

Therapeutic hypothermia applicable to cardiac surgery

OBJECTIVE

To review the beneficial and adverse effects of therapeutic hypothermia (TH) applicable to cardiac surgery with cardiopulmonary bypass (CPB) in the contexts of various temperature levels and techniques for achieving TH.

DATABASES USED

Multiple electronic literature searches were performed using PubMed and Google for articles published from June 2012 to December 2014. Relevant terms (e.g. 'hypothermia', 'cardiopulmonary bypass', 'cardiac surgery', 'neuroprotection') were used to search for original articles, letters and reviews without species limitation. Reviews were included despite potential publication bias. References from the studies identified were also searched to find other potentially relevant citations. Abstracts, case reports, conference presentations, editorials and expert opinions were excluded.

CONCLUSIONS

Therapeutic hypothermia is an essential measure of neuroprotection during cardiac surgery that may be achieved most effectively by intravascular cooling using hypothermic CPB. For most cardiac surgical procedures, mild to modest (32-36 °C) TH will be sufficient to assure neuroprotection and will avoid most of the adverse effects of hypothermia that occur at lower body core temperatures.

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.

Rationale and design of the PeriOperative ISchemic Evaluation-2 (POISE-2) trial: an international 2 × 2 factorial randomized controlled trial of acetyl-salicylic acid vs. placebo and clonidine vs. placebo in patients undergoing noncardiac surgery

BACKGROUND

Worldwide, 200 million adults undergo major noncardiac surgery annually, and 10 million of these patients will have a major vascular complication. Low-dose clonidine and low-dose acetyl-salicylic acid (ASA) may prevent major perioperative vascular complications. We therefore initiated the POISE-2 trial to establish the perioperative effects of these 2 interventions.

METHODS

The POISE-2 trial is a 2 × 2 factorial randomized controlled trial of low-dose ASA vs. placebo and low-dose clonidine vs. placebo in 10,000 patients at risk for a perioperative cardiovascular event who are undergoing noncardiac surgery. Both study drugs are initiated prior to surgery (goal 2-4 hours) and are continued after surgery. Patients, health care providers, data collectors, and outcome adjudicators are blinded to treatment allocation. The primary outcome is a composite of mortality and nonfatal myocardial infarction at 30 days after randomization.

RESULTS

To date, the POISE-2 trial has recruited more than 9,000 patients from 135 centers in 23 countries. Among the first 7,500 patients recruited, patients' mean age was 68.2 years, 53.4% were male, 34.0% had a history of vascular disease, and 38.3% had diabetes that was treated. Participants had orthopedic (38.1%), general (27.0%), urologic or gynecologic (17.2%), vascular (6.6%), thoracic (5.7%), and other (5.4%) surgery.

CONCLUSIONS

POISE-2 is a large international trial that will rigorously evaluate the effects of low-dose clonidine and ASA in patients having noncardiac surgery.

Clonidine in patients undergoing noncardiac surgery

BACKGROUND

Marked activation of the sympathetic nervous system occurs during and after noncardiac surgery. Low-dose clonidine, which blunts central sympathetic outflow, may prevent perioperative myocardial infarction and death without inducing hemodynamic instability.

METHODS

We performed a blinded, randomized trial with a 2-by-2 factorial design to allow separate evaluation of low-dose clonidine versus placebo and low-dose aspirin versus placebo in patients with, or at risk for, atherosclerotic disease who were undergoing noncardiac surgery. A total of 10,010 patients at 135 centers in 23 countries were enrolled. For the comparison of clonidine with placebo, patients were randomly assigned to receive clonidine (0.2 mg per day) or placebo just before surgery, with the study drug continued until 72 hours after surgery. The primary outcome was a composite of death or nonfatal myocardial infarction at 30 days.

RESULTS

Clonidine, as compared with placebo, did not reduce the number of primary-outcome events (367 and 339, respectively; hazard ratio with clonidine, 1.08; 95% confidence interval [CI], 0.93 to 1.26; P=0.29). Myocardial infarction occurred in 329 patients (6.6%) assigned to clonidine and in 295 patients (5.9%) assigned to placebo (hazard ratio, 1.11; 95% CI, 0.95 to 1.30; P=0.18). Significantly more patients in the clonidine group than in the placebo group had clinically important hypotension (2385 patients [47.6%] vs. 1854 patients [37.1%]; hazard ratio 1.32; 95% CI, 1.24 to 1.40; P<0.001). Clonidine, as compared with placebo, was associated with an increased rate of nonfatal cardiac arrest (0.3% [16 patients] vs. 0.1% [5 patients]; hazard ratio, 3.20; 95% CI, 1.17 to 8.73; P=0.02).

CONCLUSIONS

Administration of low-dose clonidine in patients undergoing noncardiac surgery did not reduce the rate of the composite outcome of death or nonfatal myocardial infarction; it did, however, increase the risk of clinically important hypotension and nonfatal cardiac arrest. (Funded by the Canadian Institutes of Health Research and others; POISE-2 ClinicalTrials.gov number, NCT01082874.).

Incidence of shivering after cesarean section under spinal anesthesia with or without intrathecal sufentanil: a randomized study

BACKGROUND AND OBJECTIVES

Shivering is a cause of discomfort and dissatisfaction in patients undergoing cesarean section. The objective of this study paper was to assess the impact of intrathecal administration of sufentanil on the incidence of shivering after cesarean section.

METHOD

In a prospective blinded, randomized clinical trial, pregnant women undergoing cesarean section under spinal anesthesia were enrolled. Pregnant women in labor, febrile, obese, with pregnancy-induced hypertension, anesthetic block failure or surgical complications were excluded. Patients were randomly assigned to two groups. In Group I, 10mg of 0.5% hyperbaric bupivacaine combined with 80 mcg of morphine and 2.5 mcg of sufentanil were administered. In Group II, 10mg of 0.5% hyperbaric bupivacaine combined with 80 mcg of morphine were administered. In the post-anesthesia care unit, patients were evaluated for signs of shivering by an investigator blinded to the patient's group allocation.

RESULTS

The sample consisted of 80 patients. In both groups there was a decrease in axillary temperature of patients after cesarean section (p<0.001). This decrease was not different between groups (p<0.21). In Group I, the incidence of tremor was 32.5% (13/40) and in Group II it was 62.5% (25/40) (p<0.007); RR 0.53 (CI 95% 0.32-0.87).

CONCLUSIONS

It has been suggested that the addition of sufentanil to hyperbaric bupivacaine and morphine during spinal anesthesia for cesarean section provides a decrease in the incidence of shivering in the immediate postoperative period.

Pharmacology of intravenous sedative/anesthetic medications used in oral surgery

This article provides an overview of historical and current sedative agents available to the dentist anesthetist. The surgeon is given rational choices for sedation and the individualization of drug selection for each patient. Total intravenous anesthesia is becoming increasingly popular for dental sedation because of the availability of ultra-short-acting drugs and computerized infusion technology. Levels of sedation are more easily achieved and maintained, and recovery is enhanced, which gives the operator extreme, moment-to-moment control of the anesthetic experience and improves patient outcomes.

Efficacy of Prophylactic Clonidine in Preventing Postanesthetic Shivering in Laparoscopicassisted Vaginal Hysterectomy

Objective

Postanesthetic shivering occurs in up to 60% of patients following general anesthesia and is associated with deleterious consequences. Various drugs have been used to prevent or treat postanesthetic shivering, but the ideal one has not yet been found. In this study, we have studied the efficacy of prophylactic clonidine in preventing postanesthetic shivering.

Meterials and methods

Sixty ASA (American Society of Anesthesiologists) I and II patients scheduled for laparoscopicassisted vaginal hysterectomy (LAVH) were randomly allocated to receive either clonidine 2 μg.kg—1 (group C, n = 30) or normal saline (group S, n = 30) intravenously at the time of vault closure. Core body temperature (nasopharyngeal) along with NIBP, heart rate and ECG were monitored at regular intervals. The severity of shivering was assessed according to a five-point scale (0 to 4).

Results

Significantly less shivering occurred in clonidine group 5 (17%) compared to normal saline group 20 (67%). The recovery time (between end of anesthesia and extubation) was significantly longer in the clonidine group (12.5 ± 4.3 minutes) compared with normal saline group (8.0 ± 4.5 minutes). Mean arterial blood pressure and heart rate were significantly lower in the clonidine group compared with saline group.

Conclusion

Prophylactic clonidine is effective in the prevention of postanesthetic shivering. Following clonidine administration, the recovery time was prolonged and incidence of bradycardia and hypotension were more than placebo.

How to cite this article

Chattopadhyay S, Goswami S, Rudra A. Efficacy of Prophylactic Clonidine in Preventing Postanesthetic Shivering in Laparoscopic-assisted Vaginal Hysterectomy. J South Asian Feder Obst Gynae 2013;5(3): 120-123.

Overview of therapeutic hypothermia

OPINION STATEMENT

Therapeutic hypothermia has proven neuroprotective effects in global cerebral ischemia. Indications for hypothermia induction include cardiac arrest and neonatal asphyxia. The two general methods of induced hypothermia are either surface cooling or endovascular cooling. Hypothermia should be induced as early as possible to achieve maximum neuroprotection and edema blocking effect. Endovascular cooling has the benefit of shorter time to reach target temperature but catheter insertion requires expertise and training, which may be a barrier to widespread availability. The optimum method of cooling is yet to be determined but a multimodal approach is necessary to address three phases of cooling: induction, maintentance, and rewarm. Specifying core practitioners who are well-versed in established guidelines can help integrate the multidisciplinary team that is needed to successfully implement cooling protocols. Reducing shivering to make heat exchange more efficient with tighter temperature control enables quicker time to target temperature and avoids rewarming which can lead to inadvertent increase in intracranial pressure and cerebral edema. Promising applications but yet to be determined is whether hypothermia treatment can improve outcomes in acute ischemic stroke or traumatic brain injury.

Effect of electroacupuncture in postanesthetic shivering during regional anesthesia: a randomized controlled trial

Background

Shivering during regional anesthesia is a common complication and is related to a decrease in the patient’s core body temperature. Previous studies have shown that acupuncture on specific acupoints can preserve core body temperature. The present study evaluated the effect of electroacupuncture in preventing the shivering caused by regional anesthesia.

Methods

This prospective and randomized controlled study analyzed the data from 80 patients undergoing urological surgery, who were classified as ASA I or II. Spinal anesthesia was performed in all patients using 15 mg of bupivacaine. The patients were randomly allocated to receive either placebo acupuncture (Group P, n = 40) or electroacupuncture (Group A, n = 40) for 30 min before administration of spinal anesthesia. Shivering score was recorded at 5 min intervals, with 0 representing no shivering and 4 representing the most severe shivering possible. Heart rate, blood pressure, and tympanic temperature were recorded before the intrathecal injection, and again every 5 min thereafter until 30 min.

Results

After spinal anesthesia, the decrease in tympanic temperature was less for Group A patients than Group P, with the difference being statistically significant. After 15 min, 13 patients in Group P attained a shivering score of 3 or more, compared with 3 patients in Group A. Significantly more patients in Group P attained a shivering score of at least 1.

Conclusions

The prophylactic use of electroacupuncture might maintain core body temperature, and may effectively prevent the shivering that commonly develops during regional anesthesia.

Trial registration

Australian New Zealand Clinical Trials Registry ACTRN12612000096853.

Meperidine restriction in a pediatric hospital

BACKGROUND

Much has been published revealing concerns surrounding the use of meperidine due to associated toxicities, drug interactions, and lack of proven efficacy. Thus, many adult institutions have chosen to remove or limit the use of this agent, while little has been published about the restriction of meperidine in pediatrics. Many clinicians feel there are still clinical situations in which this agent may be useful.

OBJECTIVE

To describe methods taken in a pediatric hospital to restrict the use of meperidine and review literature describing uses of meperidine as a second-line agent.

METHODS

In our pediatric institution, a policy to restrict the use of meperidine was developed, approved, and implemented. An assessment of meperidine's use 6 months prior to policy implementation was done, along with a postinitiation review of use.

RESULTS

Data revealed that the use of meperidine dropped from 646 doses in 84 patients to 226 doses in 27 patients after restriction, as anticipated. Previous to implementation of these restrictions, orthopedics physicians ordered the majority of meperidine prescriptions, while the gastroenterology service ordered the majority of meperidine prescriptions after implementation of the restriction policy. However, the use of the required form was not widely adopted, with only 30% of practitioners utilizing it postrestriction. Widespread restriction of meperidine and education about use of the form at this institution are still under way.

CONCLUSION

Not only are there limited reasons for using meperidine, there are acceptable alternatives for every known indication. Limiting meperidine's use via a restriction policy and/or removal from the institution formulary can help limit the use of this potentially toxic agent in the pediatric patient.

Intrathecal meperidine reduces intraoperative shivering during transurethral prostatectomy in elderly patients

Background

Shivering is a frequent event during the perioperative period. We performed a prospective, randomized, double-blind study to determine whether intrathecal meperidine (0.2 mg/kg) decreases the incidence and intensity of shivering after spinal anesthesia for transurethral operations.

Methods

Fifty patients scheduled for elective transurethral resection operations under spinal anesthesia were randomly allocated to two groups. Spinal anesthesia consisted of 0.5% hyperbaric bupivacaine 8 mg and, mperidine (0.2 mg/kg) (meperidine group) or, normal saline (saline group). Data collection, including sensory block level (by pinprick), blood pressure, heart rate, sublingual temperature, incidence and intensity of shivering, pruritus, nausea, and vomiting was performed at 10 minute intervals.

Results

The incidence and intensity of shivering was significantly less in the meperidine group than saline group (P = 0.012 and P = 0.008, for incidence and intensity, respectively). However, pruritus was more common in the meperidine group compared with the saline group (16% vs. 0%, P < 0.05).

Conclusions

The addition of meperidine 0.2 mg/kg to intrathecal bupivacaine lowers the incidence and severity of shivering during transurethral prostatectomy in elderly patients.

Nefopam but not physostigmine affects the thermoregulatory response in mice via alpha(2)-adrenoceptors

Nefopam, a non-opioid, centrally acting benzoxazocine analgesic, proved to be as efficient in treatment of postanaesthetic thermoregulatory shivering as clonidine or meperidine. However, its exact mechanism of action is still unclear. Potent anti-shivering activity was also demonstrated for physostigmine primarily based on cholinergic but probably also different additional mechanisms of action. Hypothesizing an involvement of alpha(2)-adrenoceptors we studied their role in nefopam- and physostigmine-mediated thermoregulation in a mouse model of nonshivering thermogenesis. To differentiate possible alpha(2)-adrenoceptor subtype-specific interactions, we analysed wildtype mice and mice with deletion of the alpha(2A)-, alpha(2B)- or alpha(2C)-adrenoceptor (knock out). Ten mice of each genotype (n = 40) were administered saline, saline plus atipamezole, 1 mg/kg nefopam, 25 mg/kg nefopam, 25 mg/kg nefopam plus atipamezole, physostigmine and physostigmine plus atipamezole intraperitoneally. Each mouse was randomly subjected to each of the seven different treatments. Afterwards, the mice were positioned into a plexiglas chamber where rectal temperature and mixed expired carbon dioxide were measured during following whole body cooling. Thermoregulatory threshold temperature of nonshivering thermogenesis and maximum response intensity were analysed. Nefopam decreased the thermoregulatory threshold temperature in wildtype, alpha(2B)- and alpha(2C)-adrenoceptor mice. This effect was partially abolished by additional administration of the alpha(2)-adrenoceptor antagonist atipamezole. In alpha(2A)-adrenoceptor knock out mice, nefopam did not affect the thermoregulatory threshold. In contrast, physostigmine decreased the thermoregulatory threshold in wildtype and all alpha(2)-adrenoceptor knock out mice independently from additional atipamezole administration. Our results indicate an important role of the alpha(2A)-adrenoceptor in the thermoregulatory response induced by nefopam but not by physostigmine in mice.

Thermoregulatory defense mechanisms

Core body temperature is normally tightly regulated by an effective thermoregulatory system. Thermoregulatory control is sometimes impaired by serious illness, but more typically remains intact. The primary autonomic defenses against heat are sweating and active precapillary vasodilation; the primary autonomic defenses against cold are arteriovenous shunt vasoconstriction and shivering. The core temperature triggering each response defines its activation threshold. Temperatures between the sweating and vasoconstriction thresholds define the inter-threshold range. The shivering threshold is usually a full 1 degrees C below the vasoconstriction threshold and is therefore a "last resort" response. Both vasoconstriction and shivering are associated with autonomic and hemodynamic activation; and each response is effective, thus impeding induction of therapeutic hypothermia. It is thus helpful to accompany core cooling with drugs that pharmacologically induce a degree of thermal tolerance. No perfect drug or drug combination has been identified. Anesthetics, for example, induce considerable tolerance, but are rarely suitable. Meperidine-especially in combination with buspirone-is especially effective while provoking only modest toxicity. The combination of buspirone and dexmedetomidine is comparably effective while avoiding the respiratory depression association with opioid administration.

Effect of active warming on shivering during spinal anesthesia

BACKGROUND

Hypothermia is considered one of the reasons for intraoperative shivering. The purpose of this study is to assess whether active warming can prevent hypothermia and shivering in young adults under spinal anesthesia.

METHODS

Fifty male patients scheduled for an elective operation on lower extremity under spinal anesthesia were randomly assigned into the warming group (n = 25) and the control group (n = 25). The active warming was performed using a forced air-warming device, a warmed blanket and warmed fluid. Axillary and tympanic temperatures, shivering degree, thermal discomfort, and anesthetic level were checked every 10 minutes after intrathecal injection of local anesthetics.

RESULTS

Patients' characteristics and anesthetic levels were comparable between the groups. Axillary and tympanic temperatures were maintained higher in the warming group than the control group 10 minutes and 20 minutes after intrathecal injection respectively. The lowest temperature in operating room was higher in the warming group (36.3 +/- 0.5degrees C) compared with the control group (35.7 +/- 0.5degrees C) (P < 0.05). Incidences of intraoperative shivering and thermal discomfort were lower in the warming group.

CONCLUSIONS

We conclude that intraoperative active warming can prevent hypothermia and shivering during spinal anesthesia.

Hypothermia for spinal cord injury

BACKGROUND CONTEXT

Interest in systemic and local hypothermia extends back over many decades, and both have been investigated as potential neuroprotective interventions in a number of clinical settings, including traumatic brain injury, stroke, cardiac arrest, and both intracranial and thoracoabdominal aortic aneurysm surgery. The recent use of systemic hypothermia in an injured National Football League football player has focused a great deal of attention on the potential use of hypothermia in acute spinal cord injury.

PURPOSE

To provide spinal clinicians with an overview of the biological rationale for using hypothermia, the past studies and current clinical applications of hypothermia, and the basic science studies and clinical reports of the use of hypothermia in acute traumatic spinal cord injury.

STUDY DESIGN/SETTING

A review of the English literature on hypothermia was performed, starting with the original clinical description of the use of systemic hypothermia in 1940. Pertinent basic science and clinical articles were identified using PubMed and the bibliographies of the articles.

METHODS

Each article was reviewed to provide a concise description of hypothermia's biological rationale, current clinical applications, complications, and experience as a neuroprotective intervention in spinal cord injury.

RESULTS

Hypothermia has a multitude of physiologic effects. From a neuroprotective standpoint, hypothermia slows basic enzymatic activity, reduces the cell's energy requirements, and thus maintains Adenosine Triphosphate (ATP) concentrations. As such, systemic hypothermia has been shown to be neuroprotective in patients after cardiac arrest, although its benefit in other clinical settings such as traumatic brain injury, stroke, and intracranial aneurysm surgery has not been demonstrated. Animal studies of local and systemic hypothermia in traumatic spinal cord injury models have produced mixed results. Local hypothermia was actively studied in the 1970s in human acute traumatic spinal cord injury, but no case series of this intervention has been published since 1984. No peer-reviewed clinical literature could be found, which describes the application of systemic hypothermia in acute traumatic spinal cord injury.

CONCLUSIONS

Animal studies of acute traumatic spinal cord injury have not revealed a consistent neuroprotective benefit to either systemic or local hypothermia. Human studies of local hypothermia after acute traumatic spinal cord injury have not been published for over two decades. No peer-reviewed studies describing the use of systemic hypothermia in this setting could be found. Although a cogent biological rationale may exist for the use of local or systemic hypothermia in acute traumatic spinal cord injury, there is little scientific literature currently available to substantiate the clinical use of either in human patients.

[Therapeutic hypothermia]

The use of therapeutic hypothermia has been shown to improve survival and neurological outcome following cardiac arrest. Patients with traumatic brain injury or ischemic stroke also responded positively to therapeutic hypothermia, which may be induced by various procedures including surface cooling, endovascular cooling catheter and cold infusion. Possible side effects include infection and hemorrhage, as well as changes in water and electrolyte levels. It is the aim of this article to provide an overview of studies to date, as well as practical guidance for the application of therapeutic hypothermia.

Management of brain injury after resuscitation from cardiac arrest

The devastating neurologic injury in survivors of cardiac arrest has been recognized since the development of modern resuscitation techniques. After numerous failed clinical trials, two trials showed that induced mild hypothermia can ameliorate brain injury and improve survival and functional neurologic outcome in comatose survivors of out-of-hospital cardiac arrest. This article provides a comprehensive review of the advances in the care of brain injury after cardiac arrest, with updates on the process of prognostication, the use of therapeutic hypothermia and adjunctive intensive care unit care for cardiac arrest survivors.