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PubMed2005

Intrathecal clonidine does not reduce post-spinal shivering.

BACKGROUND: After general or epidural anesthesia, clonidine is known to be effective in suppressing established shivering. The aim of this study was to assess the preventive effect of intrathecal clonidine on post-spinal shivering compared with intravenous (i.v.) clonidine. METHODS: One hundred and fifty patients scheduled for orthopedic surgery were randomly allocated into three groups to receive either 1 microg/kg clonidine i.v. (IV group) or the same volume of isotonic saline (control and IT groups) at 5 min before spinal anesthesia. Spinal anesthesia was performed with 12-15 mg hyperbaric bupivacaine 0.5% plus either 1 ml of saline (control and IV groups) or 150 microg clonidine (IT group). Shivering was evaluated for a period of 90 min and graded as none, mild, moderate, and severe. RESULTS: Twenty patients (40%) in the control group and 17 patients (34%) in the IT group showed shivering compared with four (8%) in the IV group. Patients with moderate-to-severe shivering were only seen in the control and IT group, and the maximal intensity of shivering was not different between the two groups. Patients in the IV group were significantly more sedated than the other groups. CONCLUSIONS: The intrathecal administration of clonidine 150 microg fails to prevent post-spinal shivering; by contrast, we have confirmed that i.v. clonidine 1 microg/kg is an effective method to prevent shivering in patients undergoing spinal anesthesia for orthopedic surgery.

Adolescent↗
PubMed1992

Relative intensity of muscular contraction during shivering.

The intensity of cold-induced shivering, quantified by surface electromyography (EMG) and then expressed as a function of the maximal myoelectrical activity (integrated EMG) obtained during a maximum voluntary contraction (MVC), was examined in this study in individuals classified by body fat. In addition, the relationship between shivering and metabolic rate (MR) and the relative contribution of various muscle groups to total heat production were studied. Ten seminude male volunteers, 5 LEAN (less than 11% body fat) and 5 NORM (greater than 15% body fat) were exposed to 10 degrees C air for 2 h. EMG of six muscle groups (pectoralis major, rectus abdominis, rectus femoris, gastrocnemius, biceps brachii, and brachioradialis) was measured and compared with the EMG of each muscle's MVC. A whole body index of shivering, determined from the mass-weighted intensity of shivering of each muscle group, was correlated with MR. After the initial few minutes of exposure, only the pectoralis major, rectus femoris, and biceps brachii continued to increase their intensity of shivering. Shivering intensity was higher in the central muscles, ranging from 5 to 16% of MVC compared with that in the peripheral muscles, which ranged from 1 to 4% of MVC. Shivering intensities were similar in the peripheral muscles for the LEAN and NORM groups, whereas differences occurred in the trunk muscles for the pectoralis major and rectus abdominis. The whole body index of shivering correlated significantly with each individual's increase in MR (r = 0.63-0.97).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2006

Shivering in the cold: from mechanisms of fuel selection to survival.

In cold-exposed adult humans, significant or lethal decreases in body temperature are delayed by reducing heat loss via peripheral vasoconstriction and by increasing rates of heat production via shivering thermogenesis. This brief review focuses on the mechanisms of fuel selection responsible for sustaining long-term shivering thermogenesis. It provides evidence to explain large discrepancies in fuel selection measurements among shivering studies, and it proposes links between choices in fuel selection mechanism and human survival in the cold. Over the last decades, a number of studies have quantified the contributions of carbohydrate (CHO) and lipid to total heat generation. However, the exact contributions of these fuels still remain unclear because of large differences in fuel selection measurements even at the same metabolic rate. Recent advances on the mechanisms of fuel selection during shivering provide some plausible explanations for these discrepancies between shivering studies. This new evidence indicates that muscles can sustain shivering over several hours using a variety of fuel mixtures achieved by modifying diet (changing the size of CHO reserves) or by changing muscle fiber recruitment (increasing or decreasing the recruitment of type II fibers). From a practical perspective, how does the choice of fuel selection mechanism affect human survival in the cold? Based on a glycogen-depletion model, estimates of shivering endurance show that, whereas the oxidation of widely different fuel mixtures does not improve survival time, the selective recruitment of fuel-specific muscle fibers provides a substantial advantage for cold survival. By combining fundamental research on fuel metabolism and applied strategies to improve shivering endurance, future research in this area promises to yield important new information on what limits human survival in the cold.

Body Temperature↗
PubMed1994

Pancuronium or vecuronium for treatment of shivering after cardiac surgery.

This randomized double-blind study compared the hemodynamic and metabolic effects of pancuronium and vecuronium during treatment of shivering after cardiac surgery with hypothermic cardiopulmonary bypass. Thirty sedated and pain-free patients who shivered after cardiac surgery were treated with pancuronium (n = 15) or vecuronium (n = 15) 0.08 mg/kg. Baseline values of heart rate (HR), mean arterial pressure, arterial and venous blood gases, total body oxygen consumption indexed to body surface area (VO2-I), and pressure work index (PWI, an estimate of myocardial oxygen consumption) were measured on arrival in the intensive care unit, at onset of shivering, and repeatedly for 2 h after treatment. Continuous ST segment analysis of leads II and V5 were used for detection of myocardial ischemia. Treatment of shivering with pancuronium decreased VO2-I by 32% (P = 0.0001). This was accompanied by a 14% increase in HR (P = 0.001) and a 10% increase in PWI (P = 0.03). Vecuronium decreased VO2-I by 36% (P = 0.003) with a 4% decrease in HR (P = 0.04) and a 6% decrease in PWI (P = 0.06). Myocardial ischemia (n = 3) and ventricular arrhythmias (n = 3) occurred in five patients treated with pancuronium. Only one patient treated with vecuronium had ventricular arrhythmia (P = 0.08). Seven patients treated with pancuronium and eight treated with vecuronium were taking beta-adrenergic blockers preoperatively which was associated with lower HR (96 +/- 16 vs 109 +/- 15 bpm; P = 0.025) and lower PWI (8.8 +/- 1.2 vs 10.7 +/- 1.92 mL.min-1 x 100 g-1; P = 0.003) at onset of shivering. However, beta-adrenergic blockers did not attenuate the relative HR increase induced by pancuronium. No relationship was found between hypercapnia and tachycardia or hypertension. These results suggest that, when compared to pancuronium for treatment of postoperative shivering, vecuronium may be advantageous because it does not increase myocardial work. The disproportionate relationship between VO2-I and PWI after treatment with muscle relaxants indicates that increased VO2-I does not contribute significantly to the hemodynamic disturbances associated with shivering. These disturbances are more likely the results of increased adrenergic activity related to pain and recovery from anesthesia. Shivering and its associated hemodynamic disturbances appear to be concomitant but independent signs of awakening.

Acid-Base Equilibrium↗
PubMed1992

Urinary bladder/pulmonary artery temperature ratio of less than 1 and shivering in cardiac surgical patients.

BACKGROUND: Temperature gradients that normally exist between body areas may be altered as a result of heat generated by shivering. METHODS AND POPULATION: Two core thermal gradients between pulmonary artery and urinary bladder were compared with shivering in 37 coronary artery bypass graft patients. Pulmonary artery and urinary temperature were measured every 15 minutes, and shivering was evaluated electromyographically. RESULTS: Shivering developed in 28 patients (76%). With shivering the pulmonary artery/urinary bladder temperature ratio was less than 1 but in the nonshivering group was greater than 1. Correlation (r value) between pulmonary artery and urinary temperature ranged from 0.93 to 0.99. Rate pressure product was higher in the shivering group than in the nonshivering group. A pulmonary artery/urinary bladder temperature ratio of less than 1 was seen with shivering in this subset of patients. CONCLUSION: Pulmonary artery and urinary bladder temperatures are readily available clinically. The combination of a ratio of less than 1 and an increase in rate pressure product should be considered suggestive of shivering in coronary artery bypass graft patients.

Adult↗
PubMed2005

Intrathecal fentanyl for prevention of shivering in cesarean section.

OBJECTIVES: The aim of this randomized double-blind study was to investigate whether 20 microg of intrathecally administered fentanyl would influence the incidence and severity of shivering in patients undergoing cesarean section. MATERIAL AND METHOD: Sixty healthy patients scheduled for cesarean section under spinal anesthesia using 2.2 ml of 0.5% hyperbaric bupivacaine with 0.2 ml of morphine 0.2 mg, were randomly allocated to receive an additional 0.4 ml of fentanyl 20 mg intrathecally (Group F) or normal saline 0.4 ml (Group S). RESULTS: The incidence of shivering three hours after spinal anesthesia was 6 of 30 patients, 20% in Group F and 15 of 30 patients, 50% in Group S. The difference was statistically significant (p < 0.05). Almost all of the shivering patients started in their first hour after spinal anesthesia (5 patients in Group F and 13 patients in Group S). None in Group F but 4 patients in Group S started shivering before their babies were delivered. The shivering score was also significantly lower in Group F (p < 0.05). Treatment for shivering was requested in 16% and 26% of the shivering patients in Group F and Group S, respectively. There was no difference in the incidence of pharmacologic side effects. The core temperature did not differ significantly between the groups during 3 hours after spinal anesthesia. CONCLUSION: The addition of 20 microg fentanyl in 2.2 ml of 0.5% hyperbaric bupivacaine with 0.2 ml of morphine 0.2 mg intrathecally can reduce the incidence and severity of intraoperative and postoperative shivering after spinal anesthesia for patients who were receiving cesarean section without increasing other side effects.

Adjuvants, Anesthesia↗
PubMed1994

[The influence of small dose intrathecal fentanyl on shivering during transurethral resection of prostate under spinal anesthesia].

Shivering during spinal anesthesia is a common complication in patients undergoing transurethral resection of prostate. The high incidence of shivering may be due to decreased core temperature secondary to peripheral vasodilation from sympathetic blockade and/or cold irrigation fluid. Shivering is known to increase O2 consumption, ventilation and cardiac output, which can result in morbidity to patients with limited cardiopulmonary reserves. The aim of this randomized double-blind study was to investigate whether 1.25 micrograms of intrathecal fentanyl administered would influence the incidence and severity of shivering in patients who underwent TURP under spinal anesthesia. In the present study, 79 patients with (n = 41) or without (n = 38) low dose fentanyl were study. The incidence of shivering was 65.8% in control group and 12.2% in the study group. The difference was statistical significance. The shivering grade (1.0 +/- 0 vs 1.76 +/- 0.7) and accumulative shivering scores (2.4 +/- 0.8 vs 12.5 +/- 5.6) were also significantly decreased in the study group (P < 0.05). Obviously, there was no difference in the incidence of pharmacologic side effect. We concluded that low dose intrathecal fentanyl is a god method for decreasing both incidence and severity of shivering during spinal anesthesia.

Aged↗
PubMed1993

[Intrathecal meperidine attenuates shivering induced by spinal anesthesia].

Shivering is a common and complex phenomenon that occurs in many patients during spinal anesthesia. Shivering can increase oxygen consumption up to 500 per cent which may be detrimental to patients with decreased myocardial reserve. The metabolic costs and cardiorespiratory consequences of shivering are important particularly for patients with anemia, coronary arterial disease, cardiopulmonary insufficient, debilitated status or are elderly. We studied whether intrathecal meperidine could prevent shivering after spinal anesthesia. 60 patients with ASA class I-II were divided into intrathecal meperidine group (Group I) (n = 30) and control group (Group II) (n = 30). Group I received spinal tetracaine 12-16 mg with meperidine 0.2 mg/kg and Group II received spinal tetracaine 12-16 mg without meperidine. During operation the highest level of spinal anesthesia, ambient and rectal temperatures, blood pressure (BP) and heart rate (HR), presence or absence of shivering, intensity of shivering in both groups were recorded. Close observation for side effects was given post-operatively. There was a significant reduction (p < .005) in incidence of shivering in group I patients (16.7%) when compared with group II (56.7%). There was no or less side effects observed with other neuraxial opioids except nausea. We concluded that intrathecal meperidine could suppress shivering induced by spinal anesthesia.

Adult↗
PubMed1988

Central myelin in the first hybrid mice produced by intercrossing homozygotes of shiverer and myelin-deficient mutants.

The first hybrid mice ('shiverer*mld' mice) produced by intercrossing the homozygotes of the shiverer (BALB/c strain) and mld (MDB/Dt strain) were used for investigating the fine structure of the myelin lamellae, immunoreactive pattern for myelin basic proteins (MBP) and Golgi impregnated images of oligodendrocytes, with special reference to the influence of aging. All of the hybrid mice had an intermediate coat color between the white of the shiverer and black-brown of the mld, and revealed the same neurological symptoms, intention tremor, ataxic behavior, etc., as those of the shiverer and mld. The central myelin lamellae of the 'shiverer*mld' mouse exhibited the similar characteristics to the shiverer type rather than the mld type from the standpoint of the infrequent occurrence of major dense lines, although they did display a tendency to increase major dense lines with aging like the mld. Observation of the immunohistochemical preparations for MBP showed that immunopositive myelin sheaths were present in the white matter, although they were far more infrequent than those of the mld mutant, probably reflecting the amount of major dense lines. Thus, in the CNS of the 'shiverer*mld' mouse, the MBP-synthesis was possibly much more disturbed than in the mld mutant, or at least, revealed an intermediate pattern between the mld and shiverer.

Animals↗
PubMed1994

THE ONTOGENY OF SHIVERING THERMOGENESIS IN THE RED-WINGED BLACKBIRD (AGELAIUS PHOENICEUS)

The ontogeny of shivering thermogenesis was investigated in the altricial red-winged blackbird (Agelaius phoeniceus). Two indices of heat production &shy; the rate of oxygen consumption (V(dot)O2) of the bird and the electromyographic (EMG) activity of the pectoralis (PECT) and gastrocnemius (GAST) muscles &shy; were measured simultaneously in adult and nestling red-winged blackbirds as they were subjected first to thermoneutral temperatures and subsequently to progressively colder ambient temperatures (Ta). The ontogenetic changes in both indices indicated that the capability for thermogenesis in nestling red-winged blackbirds improved markedly with age. The metabolic rates of 3-day-old nestlings decreased during exposure to gradually falling ambient temperatures; at best, these nestlings were only able to maintain mass-specific V(dot)O2 at levels similar to or slightly above the resting metabolic rate at thermoneutral temperatures (RMR) for a short time before metabolic rates decreased with further cooling. Shivering was detected only in the PECT muscles and was of a relatively low intensity (maximum of sevenfold increase in intensity over basal levels). The 5-day-old nestlings increased mass-specific V(dot)O2 modestly (approximately 1.4-fold) above RMR and attained slightly higher maximal factorial increases in the EMG activity of the PECT (maximum of 18-fold basal levels) when exposed to the same experimental conditions. Shivering was also detected in the GAST muscles of these birds. The most striking improvements in both measures observed during the nestling period occurred between day 5 and day 8. Eight-day-old nestlings increased metabolic rates by approximately 2- to 2.5-fold over basal levels and sustained these elevated rates for longer before becoming hypothermic. Both the PECT and GAST muscles contributed significantly to shivering thermogenesis, and these older nestlings attained much higher factorial increases in the intensity of shivering (up to 72-fold) during exposure to cold temperatures. In addition, both the range and magnitude of the dominant frequencies of muscle activity in the PECT increased during postnatal development. The PECT muscles were a principal site of shivering thermogenesis in all nestling and adult red-winged blackbirds studied here. Shivering in these muscles was a 'first line defense' against cold; the threshold temperature for shivering in the PECT muscles coincided with the lower critical temperature for oxygen consumption (TLC), and the subsequent increases in EMG activity in this muscle with further cooling correlated well with the corresponding increases in mass-specific V(dot)O2.

Journal Article↗
PubMed2001

Changes in microtubule stability and density in myelin-deficient shiverer mouse CNS axons.

Altered axon-Schwann cell interactions in PNS myelin-deficient Trembler mice result in changed axonal transport rates, neurofilament and microtubule-associated protein phosphorylation, neurofilament density, and microtubule stability. To determine whether PNS and CNS myelination have equivalent effects on axons, neurofilaments, and microtubules in CNS, myelin-deficient shiverer axons were examined. The genetic defect in shiverer is a deletion in the myelin basic protein (MBP) gene, an essential component of CNS myelin. As a result, shiverer mice have little or no compact CNS myelin. Slow axonal transport rates in shiverer CNS axons were significantly increased, in contrast to the slowing in demyelinated PNS nerves. Even more striking were substantial changes in the composition and properties of microtubules in shiverer CNS axons. The density of axonal microtubules is increased, reflecting increased expression of tubulin in shiverer, and the stability of microtubules is drastically reduced in shiverer axons. Shiverer transgenic mice with two copies of a wild-type myelin basic protein transgene have an intermediate level of compact myelin, making it possible to determine whether the actual level of compact myelin is an important regulator of axonal microtubules. Both increased microtubule density and reduced microtubule stability were still observed in transgenic mouse nerves, indicating that signals beyond synaptogenesis and the mere presence of compact myelin are required for normal regulation of the axonal microtubule cytoskeleton.

Animals↗
PubMed1980

Effect of changes in baroreceptor input on the intensity of shivering in the anaesthetised cat.

1. Shivering in the barbitone-anaesthetised cat exposed to a lowered ambient temperature was reduced by transient haemorrhagic or drug induced hypotension such that there was a positive correlation between mean arterial blood pressure and the intensity of shivering. 2. Shivering which had been reduced by haemorrhage could be restored by the reinfusion of blood, centripetal stimulation of a buffer nerve or by the intravenous administration of methoxamine. 3. The intensity of shivering was increased by the intravenous injection of methoxamine and by stimulation of a buffer nerve, although the latter response was attenuated by intact buffer nerves. 4. There was a marked variation in the importance of the different buffer nerves in maintaining shivering. 5. Shivering was abolished by deafferentation of the baroreceptors and although it could be restored by electrical stimulation of a buffer nerve methoxamine was then without effect. 6. A prolonged period (90-120 min) of hypotension (50-60 mm Hg) impaired the ability to shiver even after the hypovolaemia and hypotension had been corrected.

Animals↗
PubMed1999

Control of shivering under regional anesthesia in obstetric patients with tramadol.

PURPOSE: Tramadol in a dose of 1 mg x kg(-1) iv is effective in the treatment of shivering after general anesthesia. The current study aimed to investigate (1) whether tramadol was equally effective for shivering under regional anesthesia in obstetric patients and (2) whether effective treatment could be achieved with lower doses. METHODS: In a randomised, double-blind study, 36 obstetric patients who shivered during Cesarean section under regional anesthesia and who requested anti-shivering treatment were allocated to one of three groups for iv treatment: Group T0.5 received tramadol 0.5 mg x kg(-1) (n = 12), Group T0.25 tramadol 0.25 mg x kg(-1) (n = 13) and Group NS normal saline 0.05 ml x kg(-1) (n = 11). Treatment efficacy was evaluated subjectively by the parturient as no improvement, slight improvement, or marked improvement. The attending anesthesiologist who was blinded also independently noted the time elapsed from treatment to the time shivering subsided. Side effects such as nausea, vomiting or sedation and Apgar scores of the newborn were also noted. RESULTS: Eighty percent of parturients in Group T0.5 and 92% in Group T0.25 were judged by observers to have shivering controlled compared with 27% in Group NS (P < 0.001). The response rates of Group T0.5 and Group T0.25 were not different. There was no increased incidence of side effects in the treatment groups. CONCLUSION: We conclude that tramadol iv was effective in the treatment of intraoperative shivering during regional anesthesia for Cesarean section. There was no demonstrable difference in response rate or incidence of side effects between the two doses of 0.5 mg x kg(-1) and 0.25 mg x kg(-1).

Adult↗
PubMed2001

Urapidil does not prevent postanesthetic shivering: a dose-ranging study.

PURPOSE: To investigate the effect of 0.2 mg x kg(-1), 0.3 mg x kg(-1) and 0.4 mg x kg(-1) urapidil on the incidence and severity of postanesthetic shivering. METHODS: One hundred and fifty patients (ASA I-III) scheduled for elective abdominal, urologic or orthopedic surgery under standardized general anesthesia were randomly allocated to one of five groups (each group n=30) using a double-blind protocol: group A received 0.2 mg x kg(-1) urapidil, group B: 0.3 mg x kg(-1) urapidil, group C: 0.4 mg x kg(-1) urapidil, group D: 3 microg x kg(-1) clonidine (positive control group), and group E: saline 0.9% as placebo (negative control group). Postanesthetic shivering was scored using a five-point scale. RESULTS: Twelve patients of group A, 11 of group B, nine of group C, three of group D and 14 of group E showed signs of postanesthetic shivering. Postanesthetic shivering was significantly decreased in the clonidine group compared to the three urapidil groups and the placebo group. Significantly less patients treated with clonidine needed anti-shivering therapy. There were no significant differences between the urapidil and placebo groups. Therapeutic interventions for hemodynamic effects were not required in any group. Time to extubation, but not time to discharge, was prolonged in the clonidine group. CONCLUSION: Urapidil showed no beneficial effect on shivering in any of the doses evaluated, whereas prophylactic administration of clonidine was effective in preventing postanesthetic shivering.

Adult↗
PubMed1993

Posterior hypothalamic stimulation of anesthetized normothermic and hypothermic rats evokes shivering thermogenesis.

Normothermic (37 degrees C), anesthetized Long Evans rats given unilateral electrical stimulation (0.5 ms monophasic pulses of 100-300 microA at 50 Hz for 30 s) of the posterior hypothalamus (PH) had graded, sustained increases in EMG electrical activity of the gastrocnemius muscle (i.e. shivering). In a current-related manner, gastrocnemius muscle temperatures (Tm) immediately increased following PH stimulation, surface temperatures (Tt) did not change and colonic (core, Tc) temperatures initially fell, then subsequently rose after the applied stimulus. A biphasic pressor response occurred after PH electrical stimulation associated with tachycardia. PH electrical stimulation (0.5 ms pulses at 50 Hz for 30 s of only 40 microA) induced shivering in anaesthetized, hypothermic Long Evans rats undergoing acute cold exposure. When these same hypothermic rats were cooled further to cause shivering, PH electrical stimulation (0.5 ms pulses at 50 Hz for 30 s of only 40 microA) induced further increases in the shivering response (increases EMG area of gastrocnemius muscle) from the shivering response before PH stimulation. Results indicate that electrical stimulation of the PH can evoke shivering in anesthetized normothermic rats. Stimulation of the PH with lower current intensity can induce or increase shivering of hypothermic rats previously exposed to the cold.

Anesthesia↗
PubMed1989

Hypothermia due to an ascending impairment of shivering in hyperacute experimental allergic encephalomyelitis in the Lewis rat.

Severe hypothermia and an ascending impairment of shivering are previously undescribed clinical signs in hyperacute experimental allergic encephalomyelitis (EAE) in the Lewis rat. These occurred in hyperacute EAE induced by inoculation with guinea pig spinal cord homogenate and heat-killed Bordetella pertussis. Hypothermia was first detected on day 6-7 post-inoculation, within 12-24 h of the onset of neurological signs, and became more severe as the disease progressed. Rectal temperatures less than or equal to 30 degrees C were common at ambient temperatures of 19-22 degrees C. Shivering was assessed by palpation and by cold tremor electromyography. Shivering was absent in the tail by day 6-7 post-inoculation. The impairment then progressed to affect the hindlimbs, thorax and occasionally the forelimbs. Shivering was absent in hindlimbs with only mild or moderate weakness. Histological studies revealed perivascular inflammation with polymorphonuclear and mononuclear cells, oedema, fibrin deposition, haemorrhage, primary demyelination and axonal degeneration in the spinal cord, dorsal root ganglia and spinal roots. The brainstem was also involved but the cerebral hemispheres, including the hypothalamus, were spared. The close relationship between the severity of hypothermia and the extent of shivering impairment indicates that reduced shivering is an important cause of hypothermia in hyperacute EAE. It is concluded that this impairment of shivering is due not to hypothalamic damage but to lesions elsewhere in the central and peripheral nervous systems.

Animals↗
PubMedDate not supplied

Butorphanol for the relief of shivering associated with extradural anesthesia in parturients.

STUDY OBJECTIVE: To assess the efficacy of butorphanol for the relief of shivering following the epidural administration of 2% lidocaine. DESIGN: Randomized, double-blind study. SETTING: Labor and delivery department of a university-affiliated hospital inpatient facility. PATIENTS: Sixty-one healthy labor patients. INTERVENTIONS: Patients who had sustained shivering associated with lidocaine epidural anesthesia were given normal saline or butorphanol 1 mg. Patients were observed for 20 minutes following the administration of a study solution. MEASUREMENTS AND MAIN RESULTS: Shivering ceased within a mean time of 12.9 +/- 3.8 minutes in approximately 81% of the patients who received epidural butorphanol (p < 0.01), while 3% of the patients in the placebo group had no shivering following the administration of epidural saline. No sedation or changes in fetal heart rate were associated with epidural butorphanol. CONCLUSIONS: Epidural butorphanol is effective in the treatment of postepidural shivering associated with epidural lidocaine. Epidural agonist opioids have been reported to be efficacious in the management of postepidural shivering. This study demonstrated that a partial agonist opioid also is effective in the treatment of postepidural shivering.

Adult↗
PubMed2003

Effect of postoperative skin-surface warming on oxygen consumption and the shivering threshold.

Cutaneous warming is reportedly an effective treatment for shivering during epidural and after general anaesthesia. We quantified the efficacy of cutaneous warming as a treatment for shivering. Unwarmed surgical patients (final intra-operative core temperatures approximately 35 degrees C) were randomly assigned to be covered with a blanket (n = 9) or full-body forced-air cover (n = 9). Shivering was evaluated clinically and by oxygen consumption. Forced-air heating increased mean-skin temperature (mean (SD) 35.7 degrees C (0.4) vs. 33.2 degrees C (0.8); p < 0.0001) and lowered core temperature at the shivering threshold (35.7 degrees C (0.2) vs. 36.4 degrees C(0.2); p < 0.0001). Active warming improved thermal comfort and significantly reduced oxygen consumption from 9.7 (4.4) ml x min(-1) x kg(-1) to 5.6 (1.9) ml x min(-1) x kg(-1) (p = 0.038). However, the duration of shivering was similar in the unwarmed (37 min (11)) and active warming (36 min (10)) groups. Core temperature contributed about four times as much as skin temperature to control of shivering. Cutaneous warming improved thermal comfort and reduced metabolic stress in postoperative patients, but did not quickly obliterate shivering.

Adolescent↗