A comparison of urapidil, clonidine, meperidine and placebo in preventing postanesthetic shivering

Prophylactic Use of Intravenous Clonidine Compared to Tramadol in Prevention of Intraoperative Shivering under Regional Anesthesia

OBJECTIVES

This study aimed to evaluate the relative efficacy of prophylactic intravenous (IV) clonidine and tramadol for control of intraoperative shivering following spinal anesthesia.

MATERIALS AND METHODS

After institutional ethical clearance, 142 patients were chosen from either gender, aged 20-60 years, physical status American Society of Anesthesiology Class I and II scheduled for elective infraumbilical surgery under spinal anesthesia. Patients were randomized into two groups: Group C (n = 71) received injection clonidine 50 μg) IV in 100 ml normal saline (NS) over 10 min and Group T (n = 71) received injection tramadol 50 mg IV. In 100 ml NS over 10 min after spinal anesthesia.

RESULTS

Incidence of shivering was not significant when compared between the two groups (P > 0.05). The axillary temperatures fell significantly in Group C from the baseline and remained at a significantly lower level up to 60 min after rescue drug was administered in patients who shivered. There was a similar fall in axillary temperature in Group T in patients having shivering, but the difference was not significant. When compared between the two groups among patients who shivered, the difference in fall of temperature was not significant. Side effects such as hypotension, bradycardia, and sedation were significantly more common in clonidine group, whereas nausea was significantly more common patients of tramadol group.

CONCLUSION

Prophylactic administration of both tramadol and clonidine is effective for controlling shivering under spinal anesthesia. However, tramadol is better because of higher response rate, less sedation, and lesser hemodynamic alterations.

The evaluation of effects two different doses of hydrocortisone on the intensity of perioperative shivering in elective surgery under spinal anesthesia: A double-blind randomized controlled trial study

Background:

Post- and intra-operative shivering is one of the most complications of spinal anesthesia so recommend a suitable drug with at least complications for prevention and control of postoperative shivering. This current study aimed to compare the preventive effect of hydrocortisone on intra- and post-operative shivering in patients undergoing surgery with spinal anesthesia.

Materials and Methods:

In a clinical trial study, ninety patients who candidate for surgery with spinal anesthesia were selected and randomly divided into three groups. The first and second groups were received 1 mg/kg and 2 mg/kg hydrocortisone, respectively, and the third group was received normal saline, and postoperative shivering was compared between the three groups.

Results:

The investigation of the incidence of inter- and post-operative shivering in patients in the three groups revealed that within the study period, 31 patients suffered from shivering among which 9, 5, and 17 cases were in 1 mg/kg hydrocortisone group, 2 mg/kg hydrocortisone group, and placebo group, respectively, and according to the Chi-square test, the difference among the three groups was significant (P = 0.004).

Conclusion:

According to the obtained results, the overall conclusion of the study is that using hydrocortisone at least with the dose of 1 mg/kg as a preventive drug reduced the incidence of intra- and post-operative shivering with spinal anesthesia.

The effects of preemptive tramadol and dexmedetomidine on shivering during arthroscopy

Background:

Shivering, the rate of which in regional anesthesia is 39% is an undesired complication seen postoperatively.

Aims:

This study aims to compare the ability of preventing the shivering of preemptive tramadol and dexmedetomidine during the spinal anesthesia (SA).

Methods:

A total of 90 patients with American Society of Anesthesiologists physical status I-II, aged 18-60 years and undergoing elective arthroscopic surgery with SA were divided into three groups randomly. After spinal block, 100 mg tramadol in 100 ml saline was applied in group T- (n = 30) and 0.5 μg/kg dexmedetomidine in 100 ml saline was applied in group D- (n = 30) and 100 ml saline was administered in group P- (n = 30) in 10 min. The hemodynamics, oxygen saturation, tympanic temperature, shivering and sedation scores were evaluated and recorded intraoperatively and 45 min after a postoperative period.

Results:

In group T and D, shivering scores were significantly lower when compared with group P in the intraoperative 20^th min (P = 0.01). Sedation scores in group D were significantly higher than the baseline values (P = 0.03) and values in group T and P (P = 0.04).

Conclusions:

Preemptive tramadol and dexmedetomidine are effective in preventing the shivering under SA. In addition, dexmedetomidine was superior in increasing the level of sedation which is sufficient to prevent the anxiety without any adverse effects.

Early post-operative relief of pain and shivering using diclofenac suppository versus intravenous pethidine in spinal anesthesia

Background:

Pain and shivering are two challenging components in the post operative period. Many drugs were used for prevention and treatment of them. The aim of this study was to compare the effects of prophylactic prescription of diclofenac suppository versus intravenous (IV) pethidine in spinal anesthesia.

Materials and Methods:

We conducted a multi central, prospective, double-blind, randomized clinical trial on a total of 180 patients who were scheduled for surgery under spinal anesthesia including 60 patients in three groups. Patients were randomly allocated to receive 100 mg sodium diclofenac suppository or 30 mg IV pethidine or placebo. Categorical and continuous variables were analyzed by Chi-square test, t-test, Mann-Whitney and ANOVA or Kruskal-Wallis tests.

Results:

There was no statistical difference with regard to patient characteristics and hemodynamic indices among the three groups. Nine (15%), 10 (16.65%) and 24 (40%) of patients in diclofenac, pethidine and control groups reported pain and 2, 2, 7 patients received treatment due to it, respectively (P = 0.01). Prevalence of shivering in pethidine group and diclofenac group was the same and both of them were different from the control group (P < 0.001). Pruritus was repetitive in the pethidine group and was statistically significant (P = 0.036) but, post-operative nausea and vomiting was not significantly different among groups.

Conclusion:

A single dose of sodium diclofenac suppository can provide satisfactory analgesia immediately after surgery and decrease shivering without remarkable complications. This investigation highlights the role of pre-operative administration of a single dose of rectal diclofenac as a sole analgesic for early post-operative period.

Reduction in the incidence of shivering with perioperative dexmedetomidine: A randomized prospective study

BACKGROUND AND AIMS

Shivering is distressing to the patient and discomforting to the attending anesthesiologist, with a varying degree of success. Various drugs and regimens have been employed to abolish the occurrence of shivering. The present study aims to explore the effectiveness of dexmedetomidine in suppressing the postanesthetic shivering in patients undergoing general anesthesia.

MATERIALS AND METHODS

The present study was carried out on 80 patients, in American Society of Anesthesiologists I and II, aged 22-59 years, who underwent general anesthesia for laparoscopic surgical procedures. Patients were allocated randomly into two groups: group N (n = 40) and group D (n = 40). Group D were administered 1 μg/kg of dexmedetomidine intravenously, while group N received similar volume of saline during peri-op period. Cardiorespiratory parameters were observed and recorded during the preop, intraop, and postop periods. Any incidence of postop shivering was observed and recorded as per 4 point scale. Side effects were also observed, recorded, and treated symptomatically. Statistical analysis was carried out using statistical package for social sciences (SPSS) version 15.0 for windows and employing ANOVA and chi-square test with post-hoc comparisons with Bonferroni's correction.

RESULTS

The two groups were comparable regarding demographic profile (P > 0.05). Incidence of shivering in group N was 42.5%, which was statistically highly significant (P = 0.014). Heart rate and mean arterial pressure also showed significant variation clinically and statistically in group D patients during the postop period (P = 0.008 and 0.012). A high incidence of sedation (P = 0.000) and dry mouth (P = 0.000) was observed in group D, whereas the incidence of nausea and vomiting was higher in group N (P = 0.011 and 0.034).

CONCLUSIONS

Dexmedetomidine seems to possess antishivering properties and was found to reduce the occurrence of shivering in patients undergoing general anesthesia.

Control of shivering with clonidine, butorphanol, and tramadol under spinal anesthesia: a comparative study

INTRODUCTION

The present study was designed to evaluate the efficacy of clonidine, butorphanol, and tramadol in control of shivering under spinal anesthesia, and to compare their side effects.

METHODS

This randomized, prospective study was conducted in 90 patients who developed shivering under spinal anesthesia during various abdominal or orthopedic surgery procedures. On shivering, patients were randomly allocated to receive an intravenous, 1 mL bolus dose of 50 mg tramadol, or 1 mg butorphanol, or 150 μg clonidine, in a double blinded manner. Control of shivering, time taken for cessation, recurrence, hemodynamic changes, axillary temperatures, and side effects were noted and compared for all 3 groups. Collected data were analyzed using appropriate statistical tests.

RESULTS

Butorphanol and tramadol were more effective than clonidine in suppressing shivering. Butorphanol, tramadol, and clonidine completely controlled rigors in 83%, 73%, and 53% of cases, respectively, and incompletely suppressed rigors in 16%, 26%, and 46% of cases, respectively. Time taken to terminate rigors was significantly higher for clonidine (3.3 ± 0.9 minutes) than for butorphanol and tramadol (2.1 ± 1.0 minutes and 1.8 ± 0.5 minutes; P < 0.001).

CONCLUSION

Butorphanol had an edge over tramadol in controlling shivering with lower chances of recurrence, though both were superior to clonidine for this purpose with an early onset of action. We conclude that both these opioids control rigors better than α-2 agonists.

Pharmacologic options for reducing the shivering response to therapeutic hypothermia

Recent literature has demonstrated significant improvements in neurologic outcomes in patients who have received induced hypothermia in the setting of out-of-hospital cardiac arrest. Through multiple metabolic mechanisms, the induction of hypothermia slows the progression and devastation of transient cerebral hypoxia. Despite these benefits, the desired reduction in core temperature is often a challenging venture as the body attempts to maintain homeostasis through the induction of thermoregulatory processes aimed at elevating body temperature. Shivering is an involuntary muscular activity that enhances heat production in an attempt to restore homeostasis. For successful induction and maintenance of induced hypothermia, shivering, as well as other thermoregulatory responses, must be overcome. Several pharmacologic options are available, either used alone or in combination, that safely and effectively prevent or treat shivering after the induction of hypothermia. We conducted a PubMed search (1966-March 2009) to identify all human investigations published in English that discussed pharmacologic mechanisms for the control of shivering. Among these options, clonidine, dexmedetomidine, and meperidine have demonstrated the greatest and most clinically relevant impact on depression of the shivering threshold. More research in this area is needed, however, and the role of the clinical pharmacist in the development and implementation of this therapy needs to be defined.

[Quality of premedication and patient satisfaction after premedication with midazolam, clonidine or placebo : Randomized double-blind study with age-adjusted dosage]

BACKGROUND

Premedication aims at alleviating preoperative anxiety and nervousness and also at minimizing adverse effects. To our knowledge there is no study comparing efficacy and patient satisfaction of different premedications in age-adjusted dosage.

METHODS

In 139 patients anxiety, sedation and adverse effects were measured at 6 consecutive perioperative time points after administration of midazolam, clonidine or a placebo.

RESULTS

Midazolam showed the strongest sedative and anxiolytic effects, clonidine less and placebo none. Clonidine and midazolam reduced the risk of postoperative nausea and vomiting (PONV). Midazolam showed minimal adverse effects and the best patient satisfaction.

CONCLUSION

Midazolam was the most anxiolytic, sedative and favored premedication with the least adverse effects. Most patients would choose midazolam next time.

Year in review 2007: Critical Care--shock

The research papers on shock published in Critical Care throughout 2007 are related to three major subjects: the modulation of the macrocirculation and microcirculation during shock, focusing on arginine vasopressin, erythropoietin and nitric oxide; studies on metabolic homeostasis (acid–base status, energy expenditure and gastrointestinal motility); and basic supportive measures in critical illness (fluid resuscitation and sedation, and body-temperature management). The present review summarizes the key results of these studies and provides a brief discussion in the context of the relevant scientific and clinical background.

Meperidine and skin surface warming additively reduce the shivering threshold: a volunteer study

Introduction

Mild therapeutic hypothermia has been shown to improve outcome for patients after cardiac arrest and may be beneficial for ischaemic stroke and myocardial ischaemia patients. However, in the awake patient, even a small decrease of core temperature provokes vigorous autonomic reactions–vasoconstriction and shivering–which both inhibit efficient core cooling. Meperidine and skin warming each linearly lower vasoconstriction and shivering thresholds. We tested whether a combination of skin warming and a medium dose of meperidine additively would reduce the shivering threshold to below 34°C without producing significant sedation or respiratory depression.

Methods

Eight healthy volunteers participated on four study days: (1) control, (2) skin warming (with forced air and warming mattress), (3) meperidine (target plasma level: 0.9 μg/ml), and (4) skin warming plus meperidine (target plasma level: 0.9 μg/ml). Volunteers were cooled with 4°C cold Ringer lactate infused over a central venous catheter (rate ≈ 2.4°C/hour core temperature drop). Shivering threshold was identified by an increase of oxygen consumption (+20% of baseline). Sedation was assessed with the Observer's Assessment of Alertness/Sedation scale.

Results

Control shivering threshold was 35.5°C ± 0.2°C. Skin warming reduced the shivering threshold to 34.9°C ± 0.5°C (p = 0.01). Meperidine reduced the shivering threshold to 34.2°C ± 0.3°C (p < 0.01). The combination of meperidine and skin warming reduced the shivering threshold to 33.8°C ± 0.2°C (p < 0.01). There were no synergistic or antagonistic effects of meperidine and skin warming (p = 0.59). Only very mild sedation occurred on meperidine days.

Conclusion

A combination of meperidine and skin surface warming reduced the shivering threshold to 33.8°C ± 0.2°C via an additive interaction and produced only very mild sedation and no respiratory toxicity.

DI. Ondansetron does not reduce the shivering threshold in healthy volunteers

BACKGROUND

Ondansetron, a serotonin-3 receptor antagonist, reduces postoperative shivering. Drugs that reduce shivering usually impair central thermoregulatory control, and may thus be useful for preventing shivering during induction of therapeutic hypothermia. We determined, therefore, whether ondansetron reduces the major autonomic thermoregulatory response thresholds (triggering core temperatures) in humans.

METHODS

Control (placebo) and ondansetron infusions at the target plasma concentration of 250 ng ml(-1) were studied in healthy volunteers on two different days. Each day, skin and core temperatures were increased to provoke sweating; then reduced to elicit peripheral vasoconstriction and shivering. We determined the core-temperature sweating, vasoconstriction and shivering thresholds after compensating for changes in mean-skin temperature. Data were analysed using t-tests and presented as means (sds); P<0.05 was taken as significant.

RESULTS

Ondensetron plasma concentrations were 278 (57), 234 (55) and 243 (58) ng ml(-1) at the sweating, vasoconstriction and shivering thresholds, respectively; these corresponded to approximately 50 mg of ondansetron which is approximately 10 times the dose used for postoperative nausea and vomiting. Ondansetron did not change the sweating (control 37.4 (0.4) degrees C, ondansetron 37.6 (0.3) degrees C, P=0.16), vasoconstriction (37.0 (0.5) degrees C vs 37.1 (0.3) degrees C; P=0.70), or shivering threshold (36.3 (0.5) degrees C vs 36.3 (0.6) degrees C; P=0.76). No sedation was observed on either study day.

CONCLUSIONS

/b>. Ondansetron appears to have little potential for facilitating induction of therapeutic hypothermia.

Single-Dose Parenteral Pharmacological Interventions for the Prevention of Postoperative Shivering: A Quantitative Systematic Review of Randomized Controlled Trials

Shivering is a frequent complication in the postoperative period. The relative efficacy of pharmacological interventions to prevent this phenomenon is not well understood. We performed a systematic search for full reports of randomized comparisons of prophylactic, parenteral, single-dose antishivering interventions with inactive control (placebo or no treatment). Variable doses were converted to fixed doses. Dichotomous data on the absence of shivering were analyzed by using relative benefit (RB) and number needed to treat (NNT) with 95% confidence intervals (CI). Data from 27 trials (1348 adults received an antishivering intervention; 931 were controls) were analyzed. The average incidence of shivering in controls was extremely frequent (52%). Clonidine 65-300 microg (1078 patients), meperidine 12.5-35 mg (250 patients), tramadol 35-220 mg (250 patients), and nefopam 6.5-11 mg (204 patients) were tested in at least 3 trials each. All were more effective than control. For clonidine, meperidine, and nefopam, there was some weak evidence of dose responsiveness. For small-dose clonidine (65-110 microg), the RB compared with control was 1.32 (95% CI, 1.16-1.51); for medium-dose clonidine (140-150 microg), the RB was 1.83 (95% CI, 1.47-2.27); and for large-dose clonidine (220-300 microg), the RB was 1.52 (95% CI, 1.30-1.78). For all clonidine regimens combined, the RB was 1.58 (95% CI, 1.43-1.74), with an NNT of 3.7. For all meperidine regimens combined, the RB was 1.67 (95% CI, 1.37-2.03), with an NNT of 3. For all tramadol regimens combined, the RB was 1.93 (95% CI, 1.56-2.39), with an NNT of 2.2. For all nefopam regimens combined, the RB was 2.62 (95% CI, 2.02-3.40), with an NNT of 1.7. Methylphenidate, midazolam, dolasetron, ondansetron, physostigmine, urapidil, and flumazenil were tested in no more than 3 trials each, with a limited number of patients.

Postanaesthetic shivering: epidemiology, pathophysiology, and approaches to prevention and management

Along with nausea and vomiting, postanaesthetic shivering is one of the leading causes of discomfort for patients recovering from general anaesthesia. The distinguishing factor during electromyogram recordings between patients with postanaesthetic shivering and shivering in fully awake patients is the existence of clonus similar to that recorded in patients with spinal cord transection. Clonus coexists with the classic waxing and waning signals associated with cutaneous vasoconstriction (thermoregulatory shivering). The primary cause of postanaesthetic shivering is peroperative hypothermia, which sets in because of anaesthetic-induced inhibition of thermoregulation. However, shivering associated with cutaneous vasodilatation (non-thermoregulatory shivering) also occurs, one of the origins of which is postoperative pain. Apart from causing discomfort and aggravation of pain, postanaesthetic shivering increases metabolic demand proportionally to the solicited muscle mass and the cardiac capacity of the patient. No link has been demonstrated between the occurrence of shivering and an increase in cardiac morbidity, but it is preferable to avoid postanaesthetic shivering because it is oxygen draining. Prevention mainly entails preventing peroperative hypothermia by actively rewarming the patient. Postoperative skin surface rewarming is a rapid way of obtaining the threshold shivering temperature while raising the skin temperature and improving the comfort of the patient. However, it is less efficient than certain drugs such as meperidine, clonidine or tramadol, which act by reducing the shivering threshold temperature.