Intensity Of Shivering Research Articles

Comparative Study between Dexmedetomidine and Fentanyl as Adjuvants to Bupivacaine for Prevention of Post Spinal Shivering in Caesarean Sections

Abstract Background Shivering is a common complication in regional anesthesia during cesarean sections. It can impair monitoring and increase oxygen demand, CO2 production, and wound pain, healing, and discharge. Spinal anesthesia can increase vulnerability to hypothermia, leading to shivering. Dexmedetomidine and fentanyl have been shown to prevent post-spinal shivering. Aim of the Work This study aimed to compare the efficacy and safety of fentanyl and dexmedetomidine in preventing perioperative shivering and their effects on block intensity, hemodynamics, sedation, postoperative pain, and analgesic requirement. Patients and Methods 150 obstetric patients were included and randomized into three equal groups: control, fentanyl, and dexmedetomidine group. Each group received 12.5 mg hyperbaric bupivacaine 0.5% intrathecally with different adjuvants. Results Both fentanyl and dexmedetomidine groups showed a decreased incidence and intensity of shivering compared to the control group. There was no statistically significant difference between the two groups in this regard (p-value >0.05). The onset and duration of sensory and motor block were faster and prolonged in both fentanyl and dexmedetomidine groups compared to the control group, but dexmedetomidine showed faster onset and more prolonged duration than fentanyl. Dexmedetomidine also showed a statistically significant difference regarding hypotension (p-value <0.05) but non-significant regarding bradycardia (p-value >0.05) compared to other groups. There were no statistically significant differences in sedation intensity between the groups (p-value >0.05). Fentanyl showed a higher incidence of nausea, vomiting, and pruritis compared to other study groups. Conclusion Both fentanyl and dexmedetomidine are safe to use with bupivacaine for prevention of perioperative shivering in cesarean sections. Both drugs decreased the incidence and intensity of shivering, and dexmedetomidine was more effective in terms of prolongation of sensory and motor block duration and reducing opioid requirements. Dexmedetomidine showed fewer side effects during the intra and postoperative period compared to fentanyl.

Effect of a vapor barrier in combination with active external rewarming for cold-stressed patients in a prehospital setting: a randomized, crossover field study

BackgroundUse of a vapor barrier in the prehospital care of cold-stressed or hypothermic patients aims to reduce evaporative heat loss and accelerate rewarming. The application of a vapor barrier is recommended in various guidelines, along with both insulating and wind/waterproof layers and an active external rewarming device; however, evidence of its effect is limited. This study aimed to investigate the effect of using a vapor barrier as the inner layer in the recommended “burrito” model for wrapping hypothermic patients in the field.MethodsIn this, randomized, crossover field study, 16 healthy volunteers wearing wet clothing were subjected to a 30-minute cooling period in a snow chamber before being wrapped in a model including an active heating source either with (intervention) or without (control) a vapor barrier. The mean skin temperature, core temperature, and humidity in the model were measured, and the shivering intensity and thermal comfort were assessed using a subjective questionnaire. The mean skin temperature was the primary outcome, whereas humidity and thermal comfort were the secondary outcomes. Primary outcome data were analyzed using analysis of covariance (ANCOVA).ResultsWe found a higher mean skin temperature in the intervention group than in the control group after approximately 25 min (p < 0.05), and this difference persisted for the rest of the 60-minute study period. The largest difference in mean skin temperature was 0.93 °C after 60 min. Humidity levels outside the vapor barrier were significantly higher in the control group than in the intervention group after 5 min. There were no significant differences in subjective comfort. However, there was a consistent trend toward increased comfort in the intervention group compared with the control group.ConclusionsThe use of a vapor barrier as the innermost layer in combination with an active external heat source leads to higher mean skin rewarming rates in patients wearing wet clothing who are at risk of accidental hypothermia.Trial registrationClinicalTrials.gov identifier: NCT05779722.

Effect of i.v. Magnesium Sulphate versus i.v. Dexamethasone on Intraoperative Haemodynamic and Postoperative Analgesia after Spinal Anaesthesia in Lower Limb Surgeries: A Randomised Clinical Study

Introduction: Intrathecal adjuvants have gained favour in recent years with the goal of extending the duration of a block. Among these, Dexamethasone possesses anti-inflammatory and analgesic action and can be given as an adjuvant to local anaesthetics to enhance the efficacy of regional anaesthesia, as well as to decrease the intensity of shivering. The addition of Magnesium sulphate (MgSO4 ) to spinal anaesthesia helps in improving postoperative analgesia in an orthopaedic setting. Aim: To compare the effects of Intravenously (i.v.) MgSO4 and i.v. dexamethasone on intraoperative haemodynamics, the time to achieve dermatome T10 intraoperatively, and to compare postoperative Visual Analogue Scale (VAS) scores between the two groups at 1, 3, 6, 12, and 24 hours after surgery. Materials and Methods: This randomised clinical trial was conducted, and patients were randomly divided into two groups. Group M (n=40): MgSO4 40 mg/kg given 15 minutes before spinal anaesthesia in 100 mL normal saline infusion i.v. Group D (n=40): Dexamethasone 8 mg given 15 minutes before spinal anaesthesia in 100 mL normal saline infusion i.v. The parameters assessed included haemodynamic parameters, time to achieve dermatome T10 intraoperatively, postoperative VAS score at 1, 3, 6, 12, and 24 hours after surgery, and any side-effects like sedation, respiratory depression, nausea, vomiting, pruritus, urinary retention, bradycardia, and hypotension. Statistical testing was conducted using the statistical software Statistical Package for Social Sciences (SPSS) 28.0. Results: There was no significant difference in demographic variables (age and gender) between the two groups (p-value&gt;0.05). However, the decrease in mean heart rate, Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP), and Mean Arterial Blood Pressure (MAP) was greater in group D compared to group M at different time intervals (p-value&lt;0.05). Additionally, dermatome level T10 was achieved earlier in group D by approximately two minutes compared to group M (6.95±0.39 minutes versus 5.03±0.16 minutes, respectively, p-value&lt;0.001). Conclusion: An i.v. infusion of 8 mg dexamethasone in 100 mL normal saline was more effective compared to an i.v. infusion of 40 mg/kg MgSO4 in terms of achieving more stable haemodynamics intraoperatively and achieving the T10 dermatome level earlier.

COMPARING THE EFFECTS OF LOW DOSES OF KETAMINE AND TRAMADOL IN THE PREVENTION OF POST-SPINAL ANESTHESIA SHIVERING IN CESAREAN SECTION

Post-spinal anesthesia (SA) shivering is a common complication following cesarean section (CS) and can pose various challenges for both patients and healthcare providers. Pethidine has been the standard treatment for this issue, but it is not recommended for nursing mothers. This study aimed to compare the efficacy of low-dosage tramadol (T), ketamine (K), and a placebo (P) in managing post-SA shivering in pregnant women undergoing CS. The objective of this study was to evaluate and compare the frequency and intensity of shivering in post-CS patients treated with low-dosage tramadol, ketamine, or placebo. Additionally, we sought to assess the impact of shivering on patients and draw conclusions about the most effective medication for shivering management in this context. A randomized, double-blind trial was conducted at the tertiary care hospital in Lahore, Pakistan, from February 2019 to December 2020. A total of 180 pregnant women undergoing CS with SA were enrolled and randomly assigned to one of three groups: tramadol (T), ketamine (K), or placebo (P). The study-maintained uniformity in the demographic characteristics of all patients. The frequency and intensity of post-SA shivering were recorded, and these observations were compared among the three groups. The results of this study revealed significant differences among the three groups regarding the incidence and intensity of post-SA shivering. Shivering was observed in 33 (55.0%) patients in the ketamine (K) group, 12 (20%) in the tramadol (T) group, and 39 (65%) in the placebo (P) group (P = 0.0001). Tramadol demonstrated the highest efficacy in managing post-SA shivering, followed by a lower dosage of ketamine (K). The high incidence of shivering in the placebo group emphasized the necessity for preventive shivering management strategies in the context of CS under SA. Based on the results it can be concluded that the low-dose tramadol and ketamine are effective in reducing shivering frequency and intensity compared to a placebo. They can be considered as alternative options for nursing mothers who face challenges with pethidine. Proactive measures are recommended to manage post-SA shivering for better patient outcomes following CS under SA.

The Effect of Ketamine Versus Tramadol on Prophylactic Post-Spinal Shivering in Those Patients Undergoing Orthopedic Surgery

Background/Objective: Orthopedic patients have a particularly high risk for post-spinal shivering, a typical consequence of spinal anesthesia. Without treatment, shaking may worsen wound pain, increase oxygen use, and impair healing. There have been a number of studies looking at the efficacy of ketamine and other medications for reducing post-spinal shivering. Despite this, there is a dearth of data on more effective and widely available preventive medicines. As a result, the purpose of this research was to evaluate the efficacy of 0.25 mg/kg of Ketamine (K) against 0.5 mg/kg of Tramadol (T) in preventing shivering after spinal anesthesia. Methodology: 200 patients who were to have orthopedic surgery under spinal anesthesia were randomly chosen to participate in this prospective cohort study. Patients who were given a prophylactic dosage of intravenous ketamine prior to spinal anesthesia are referred to as the Ketamine group(n=100), whereas those who were given Tramadol are referred to as the Tramadol group (N=100). During the intraoperative phase, vital signs such as shivering intensity and frequency, blood pressure, heart rate, and axillary body temperature were monitored hourly at 10-minute intervals for a whole hour. Results: There were 87 patients (43%) who had post-spinal shivering; this number was 32 (32%) for those given ketamine and 55(55%) for those given tramadol (p=0.001). With a p-value of 0.000, the incidence of nausea and vomiting was statistically significantly higher in the tramadol group of 82(82%). The ketamine group had significantly more intraoperative sedation than the tramadol group (p 0.007). Conclusion: After spinal anesthesia, low-dose ketamine is more active in lowering the frequency and intensity of shivering. Therefore, we advise patients having orthopedic surgery under spinal anesthesia to take low-dose ketamine beforehand as a preventative measure against post-spinal shivering. Keywords: Ketamine, Tramadol, Shivering, Orthopedic surgery

Modulation of cold-induced shivering activity by intermittent and continuous voluntary suppression.

This investigation assessed the physiological effects of voluntary suppression of shivering thermogenesis in response to whole body cooling. Eleven healthy volunteers underwent passive air cooling (10°C), across three visits: NO_SUP, where participants allowed their body to freely regulate against the cold; FULL_SUP, where participants constantly suppressed shivering; INT_SUP, where participants intermittently suppressed shivering (5 min phases), interspersed with 5 min free regulation. Shivering was assessed via electromyography (EMG), mechanomyography (MMG), and whole body oxygen uptake (V̇o2), whereas body temperature and heat exchange were assessed via skin temperature, rectal temperature, and heat flux sensors. A 29% increase was observed in shivering onset time in the FULL_SUP trial compared with NO_SUP (P = 0.032). Assessing shivering intensity, EMG activity decreased by 29% (P = 0.034), MMG activity decreased by 35% (P = 0.031), whereas no difference was observed in V̇o2 (P = 0.091) in the FULL_SUP trial compared with NO_SUP. Partitioning the no-suppression and suppression phases of the INT_SUP trial, acute voluntary suppression significantly decreased V̇o2 (P = 0.001), EMG (P < 0.001), and MMG (P = 0.012) activity compared with the no-suppression phases. Shivering activity was restored in the no-suppression phases, equivalent to that in the NO_SUP trial (P > 0.3). No difference was observed in thermal metrics between conditions up to 60 min (P > 0.4). Humans can both constantly and periodically suppress shivering activity, leading to a delay in shivering onset and a reduction in shivering intensity. Following suppression, regular shivering is resumed.

A systematic review on considering the role of Magnesium in preventing post-anesthesia shivering.

Shivering following anesthesia is caused by disturbed regulation of body temperature and causes an increase in tissue oxygen consumption and cardio-pulmonary activity. Choosing the right medicine to reduce shivering with the most negligible side effects in surgery is essential. Magnesium is prescribed intravenously, epidurally, or intra-peritoneally. Each of these methods can have different effects in different surgical operations. In this review, we are looking for randomized clinical trials that compared preoperative magnesium administration with a control group and included studies that evaluated the degree of shivering as a primary outcome variable. This study aimed to evaluate pre-operative magnesium's effect in preventing shivering after surgery. This article was a systematic review type, in which all quality articles published until the end of 2021 were searched with the keywords magnesium, shivering, surgery, and prevention via different databases, including PubMed, Cochrane Central Register of Tested Controlled, EMBASE and Web of Science. In the initial search, 3294 publications were identified. 64 articles were included in this study. The results indicated that shivering in the magnesium group with IV epidural injection inside the peritoneum was significantly reduced compared to the control group. It was also identified in the examination of symptoms. Variants such as extubation time, length of stay in PACU, magnesium serum concentration, spinal c-fos mRNA expression, nausea or vomiting, sedation, itching, pressure drop, and bradycardia were significantly less reported than the control group. In general, the results showed that the preventive use of magnesium could decrease the intensity and number of post-anesthesia shivering and other post-anesthesia symptoms.

Comparison of intrathecal tramadol and Magnesium sulphate for the prevention of post-spinal shivering in infra umbilical surgeries: A randomized, double blinded and controlled study

: Post anesthesia shivering is a common complication after spinal anesthesia. Intrathecal Magnesium sulphate (MgSO4) and tramadol are the most effective and safe adjuvants with minimal side effects. The aim of this study was to compare the effect of intrathecal tramadol versus intrathecal MgSO4 with bupivacaine for the prevention of post-spinal anesthesia shivering. : In this prospective randomized, double-blinded controlled study, 105 patients scheduled for infraumbilical surgeries were randomly allocated into three groups. Group C(35) received 3.0ml of hyperbaric bupivacaine 0.5% (15mg)+0.5ml of normal saline, Group T (35) received 3.0ml of hyperbaric bupivacaine 0.5% (15mg)+25mg of tramadol in 0.5ml saline, and Group M (35) received 3.0ml of hyperbaric bupivacaine 0.5% (15mg)+100mg of magnesium sulphate in 0.5ml saline. The primary outcomes were to find the incidence and intensity of shivering. The secondary outcome was to find out the incidence of complications.: All the 3 groups were comparable with respect to demographic characteristics. Shivering was observed in 68.6% of the patients in Group C, 48.6% patients in Group T and 40% patients in Group M. The incidence of shivering were statistically significant between Groups C and T (P= 0.003) and Groups C and M (P=0.001) but not between Groups T and M (P=0.480). The incidence of complications such as hypotension, bradycardia, nausea, vomiting,itching and respiratory depression were not statistically significant in between the groups.: This study concluded that both intrathecal MgSO4 100mg and tramadol 25mg with hyperbaric bupivacaine reduces the incidence and intensity of shivering compared to control group after spinal anesthesia.

Comparison of Intravenous Ketamine with Intrathecal Meperidine in Prevention of Post-anesthetic Shivering after Spinal Anesthesia for Lower Limb Orthopedic Surgeries: A Double-blind Randomized Clinical Trial.

Post-anesthetic shivering is one of the most common complications after anesthesia. Ketamine has been considered to be an effective treatment for post-anesthetic shivering, but the evidence for its therapeutic benefit after spinal anesthesia is limited. The aim of this study was to compare the effects of intravenous ketamine with intrathecal meperidine in the prevention of post-anesthetic shivering after spinal anesthesia for lower limb orthopedic surgeries. In a double-blind randomized parallel-group clinical trial, a total of 150 patients scheduled for lower limb orthopedic surgeries under spinal anesthesia were selected and randomly divided into three equally sized groups of intravenous ketamine (0.5 mg/kg), intrathecal meperidine (0.2mg/kg) or intravenous normal saline (as placebo). The intensity of shivering in patients were evaluated during surgery and after transfer into the post anesthesia care unit. Also, changes in patients' drowsiness, nausea, vomiting, pruritus, mean arterial pressure, heart rate, and arterial oxygen saturation (SPO2) during surgery and until the end of anesthesia were evaluated. In all times of evaluation (20, 60, 80, 100 and 120 minutes after onset of spinal anesthesia) patients in control group showed a greater intensity of shivering compared to other groups. However, patients who received intrathecal meperidine experienced significantly lower intensity of post anesthetic shivering (p<0.05). The results showed a significant mean arterial pressure and heart rates differences between the three groups, only on 20 and 60 minutes after initiation of spinal anesthesia. The incidence of nausea, vomiting, and pruritus was not significantly different in all three groups, although all patients who received ketamine experienced drowsiness after surgery (p<0.001). The results of the present study showed that, although both intrathecal meperidine and intravenous ketamine could effectively prevent postoperative shivering after spinal anesthesia in lower limb orthopedic surgeries, intrathecal meperidine was associated with more efficacy benefits and a lower frequency of side effects such as post-anesthesia drowsiness.

Cross-sectional Study on Effects of Ondansetron and Meperidine in the Prevention of Postoperative Shivering after Spinal Anesthesia

Purpose: Post-anesthesia shivering is one of the most common problems after surgery and may lead to multiple complications such as hypoxemia, lactate acidosis and catecholamine release. The purpose of this study was to compare the effects of intravenous meperidine and ondansetron on postoperative shivering in patients having an elective cesarean section under spinal anesthesia. Design: Cross-sectional study Methods: In this cross-sectional study, 105 patients with the age of 18-45 years and ASA class I-II undergoing elective cesarean section were randomly assigned into three groups. Group O was administered 8mg ondansetron, group M patients were given 0.4mg/kg meperidine and group P was placebo that was administered with 2cc of saline intravenously after the delivery. The incidence and intensity of shivering and postoperative nausea was monitored and recorded by the trained nurse. The data obtained was analyzed using SPSS v18. Results: All three groups (n=35) had no significant difference in terms of age, weight and time of spinal anesthesia. Postoperative shivering was reported in 4 patients (11.4%) in group A and 3 patients (8.6%) in group B and in 14 patients (40%) in group C. The incidence of postoperative shivering was significantly less in groups A and B as compared to the placebo, p=0.03. The intensity of shivering was greater in group C as compared to groups A and B, p=0.01. The incidence and intensity of postoperative nausea was significantly less in group A, p=0.03, p&lt;0.001, respectively, while no difference was reported in groups B and C, p&lt;0.05. Conclusion: 8mg ondansetron and 0.4 mg/kg of meperidine are equally effective in managing postoperative shivering; however, ondansetron has an additional effect of reducing the incidence of postoperative nausea among patients undergoing caesarean section with spinal anesthesia.

The Preventive Effects of two Different Doses of Dexmedetomidine on Shivering in Cesarean Section under Spinal Anesthesia

Introduction: One of the side effects caused by spinal anesthesia is seizures of impaired body temperature regulation, which in addition to causing concern for the mother, can lead to problems such as cardiovascular and respiratory disorders. This has led to the choice of the appropriate drug to reduce shivering, with the least neonatal and maternal side effects in cesarean section. The main purpose of this study was to compare the prophylactic effect of intravenous dexmedetomidine at two different doses for cesarean section induced shivering under spinal anesthesia. Methods: This article is a double blind randomized clinical trial study performed in Isfahan University of Medical Sciences (Alzahra and Shahid Beheshti). The target population of the study was pregnant women with indication of cesarean section. In this study 60 pregnant women were divided into three groups. In the first group patients were injected with 2.5 mg / kg dexmedetomidine, in the second group patients with 5 mg / kg dexmedetomidine and in the third group with similar volume, normal saline was injected and the shivering intensity in patients with the use of Grassi and Mahajan criteria was evaluated. Finally, the collected data were analyzed using SPSS software and Kruskal-Wallis One-Way ANOVA tests. Results: According to the statistical analysis of the data, after cesarean section with spinal anesthesia, shivering intensity in the 5mg / kg dexmedetomidine group was lower than in the 2.5mg group and less than the control group. Normal saline was given as prophylaxis. Conclusion: Intravenous dexmedetomidine, especially at a dose of 5 μg / kg, has a significant effect on reducing postoperative shivering by cesarean section with spinal anesthesia. Keywords: Dexmedetomidine, Shivering, Cesarean section, Spinal anesthesia

Relationship Between Brown Adipose Tissue and Shivering in Cold‐Exposed Humans

Background An inverse relationship between brown adipose tissue (BAT) volume and shivering intensity has previously been reported in humans. Considering its small volume in adult humans, this inverse relationship may be explained by the regional distribution of BAT. It has been postulated that the paraspinal depot may be critical to heating the spinal cord to maintain neural conductivity under cold stimulation. However, this local heating may also suppress the drive to shiver, a phenomenon previously shown in guinea pigs. Objective The research objective was to determine whether the presence of paraspinal BAT can modulate the intensity and pattern of shivering in lean, healthy, adult humans. Hypothesis We propose that paraspinal BAT thermogenesis can supress shivering intensity and modulate the shivering pattern. Methodology The present data includes 23 young women who completed a 3h mild cold exposure protocol, using a liquid-conditioned suit perfused with water at 18°C. During cold exposure, participants remained supine in a PET/CT scanner. An i.v. bolus of [11C]-acetate and [18F]FDG were given sequentially, with each injection followed by a 30 min list-mode dynamic PET acquisition to quantify depot-specific BAT oxidative metabolism and glucose uptake, respectively. Finally, a whole-body static PET acquisition was performed to quantify the total BAT volume and distribution. Surface electromyography (sEMG) was used to characterize shivering activity in 8 different muscles. Shivering intensity and shivering pattern were determined using custom-designed EMG algorithms. In brief, the two distinct shivering patterns (continuous vs burst shivering) are distinguished according to differences in frequency of occurrence (4-8 Hz for continuous vs. 0.1-0.2 Hz for bursts) and intensity [2-5% maximal voluntary contraction (MVC) for continuous vs. 7-15% MVC for bursts]. Results Total BAT volume was estimated at 53 mL (95% CI: 34 to 72 mL) with paraspinal BAT volume accounting for 9% (95% CI: 5 to 13%) of total BAT. Mean shivering intensity under this cold stimulus was 3.0 % MVC (95% CI: 2.0 to 3.8 %). Shivering bursts occurred at a frequency of 2.8 bursts/min (95% CI: 2.3 to 3.2 bursts/min), eliciting a shivering intensity of 9.6 % MVC (95% CI: 5.9 to 13.3 % MVC), while the more continuous low-intensity shivering was maintained at 3.0 % MVC (95% CI: 1.6 to 4.4% MVC). Pearson correlations revealed no associations between total BAT volume, shivering intensity or shivering pattern. Similarly, paraspinal BAT volume was not associated with any shivering outcomes. Conclusion The role of BAT in humans is still not clearly elucidated. Here we showed that in premenopausal women, neither total BAT volume nor paraspinal BAT are associated with shivering intensity or shivering pattern. Further studies are required to determine whether BAT plays a more regionalized role, unique to each depot, or more globally on whole-body energy metabolism.

English

BACKGROUND Shivering is commonly encountered complication following spinal anaesthesia leading to discomfort and interference with monitoring during caesarean section. There is no definite aetiology for this and hence no definite treatment is available. Hence, we wanted to study effect of temperature variation of spinal inject on post spinal shivering during caesarean section. METHODS This prospective randomized double-blind study was conducted on 80 parturients posted for elective caesarean section allocated to two groups of 40 each receiving 2.0 mL of 0.5 % hyperbaric bupivacaine with temperature of 220 C (group I) or 370 C (group II) intrathecally at L3 - L4 interspace. Onset of shivering, its severity and incidence were noted. Data was analysed using various tests and P-value &lt; 0.05 was considered as significant and P-value &lt; 0.01 was considered highly significant. RESULTS Demographic characters, surgical parameters as well as onset time of sensory blockade, maximum sensory blockade, time to achieve maximum sensory and motor blockade were comparable in the two groups. Shivering was present in 57.5 % of patients in group I and 32.5 % in group II and this difference was statistically significant. Overall, shivering percentage was 45 % although difference in mean onset time was not significant in the two groups. Grades of shivering were comparable in both groups. CONCLUSIONS Warm solutions used intrathecally can reduce incidence of shivering following spinal anaesthesia in caesarean section although it doesn’t influence intensity of shivering. KEY WORDS Neuraxial Anaesthesia, Temperature Variation, Post Spinal Shivering

Intravenous Ketamine for the Prevention of Post Anesthetic Shivering in Spinal Anesthesia: A Randomized Double-Blind Placebo-Controlled Trial

Spinal anesthesia (SA) may impair thermoregulatory control, which may result in shivering, which is a potentially harassing complication. The aim of the current study was to evaluate the prophylactic effects of intravenous ketamine on the prevention of shivering in patients who underwent elective cesarean section (CSs) under SA. In this double-blind, randomized placebo controlled trial, a total of 90 parturients under SA using hyperbaric bupivacaine 12.5 mg were allocated in two groups to receive ketamine 0.3 mg/kg or 0.9% saline following delivery. After induction of SA, patients were observed for the incidence and intensity of shivering using a four-point scale. Shivering was observed in 24 patients (53.3%) in the saline group and 15 patients (33.3%) in the ketamine group. Median (quartiles 1 and 3) of the intensity of shivering was 1 (0-2) and 0 (0-2) in saline and ketamine groups, respectively. Time from spinal anesthesia to the beginning of shivering was 33.1±11.7 min in saline versus 41.6±20.7 min in the ketamine group. The incidence of nausea, vomiting, hypotension, and bradycardia was not different between the groups. A significantly higher incidence of nystagmus and sedation was observed in the ketamine group when compared with the saline group administration of low dose i.v. Ketamine (0.3 mg/kg) was effective in lowering shivering intensity during CSS under spinal anesthesia, though side effects such as nystagmus and sedation may restrict its effectiveness.

A comparative study between dexmedetomidine and dexamethasone as an intrathecal adjuvant for prevention of perioperative shivering in cesarean section

BackgroundOne of the most common problems in parturients receiving regional anesthesia during cesarean section is shivering. It usually interferes with the readings of the oxygen plethysmography (SpO2) and electrocardiogram (ECG). It expands the needs for oxygen and increases creation of carbon dioxide about four folds.The aim of this work is to compare the efficacy of dexamethasone and dexmedetomidine in prevention of perioperative shivering when added to hyperbaric bupivacaine intrathecally in cesarean sections (CS) and their effect on the intraoperative hemodynamics, intensity of the block, sedation, and postoperative analgesic requirement.ResultsStudy included 60 obstetric patients who fulfilled all the inclusion criteria and were randomized into 2 equal groups, each consisting of 30 patients, namely group A (dexmedetomidine group) and B (dexamethasone group).Group A patients received 5 μg dexmedetomidine with 12.5 mg hyperbaric bupivacaine 0.5% intrathecally.Group B patients received 8 mg dexamethasone then 12.5 mg hyperbaric bupivacaine 0.5% intrathecally.The comparison included assessment of intra- and postoperative hemodynamics, duration of surgery, assessment of sensory and motor block, assessment for shivering and sedation, and assessment of adverse events.This study showed that there were a small number of patients complaining of shivering (five patients in group A and seven patients in group B) with no statistical difference between both groups in the incidence and intensity of shivering. Time to two segment regression (minutes) was longer in group B compared to group A, and also, time to first analgesic rescue was longer in group B compared to group A. For sedation intensity, there was statistical difference between both groups as all patients in group A were sedated compared to six patients only in group B. There was no statistical difference between both groups as regards incidence of adverse effects.ConclusionWe concluded that both drugs can be added safely to bupivacaine, and both dexmedetomidine and dexamethasone decreased the incidence and the intensity of shivering. Dexamethasone was found to prolong the duration of sensory block and delay opioid requirements post-operatively, while dexmedetomidine is more effective in sedating the patients intra- and postoperatively.

Comparative study between intrathecal dexmedetomidine and intrathecal magnesium sulfate for the prevention of post-spinal anaesthesia shivering in uroscopic surgery; (RCT)

BackgroundHypothermia and shivering are common complications after spinal anaesthesia, especially after uroscopic procedures in which large amounts of cold intraluminal irrigation fluids are used. Magnesium sulfate and dexmedetomidine are the most effective adjuvants with the least side effects. The aim of this study was to compare the effects of intrathecal dexmedetomidine versus intrathecal magnesium sulfate on the prevention of post-spinal anaesthesia shivering.MethodsThis prospective randomized, double-blinded controlled study included 105 patients who were scheduled for uroscopic surgery at the Kasr El-Aini Hospital. The patients were randomly allocated into three groups. Group C (n = 35) received 2.5 ml of hyperbaric bupivacaine 0.5% (12.5 mg) + 0.5 ml of normal saline, Group M (n = 35) received 2.5 ml of hyperbaric bupivacaine 0.5% (12.5 mg) + 25 mg of magnesium sulfate in 0.5 ml saline, and Group D (n = 35) received 2.5 ml of hyperbaric bupivacaine 0.5% (12.5 mg) + 5 μg of dexmedetomidine in 0.5 ml saline. The primary outcomes were the incidence and intensity of shivering. The secondary outcomes were the incidence of hypothermia, sedation, the use of meperidine to control shivering and complications.ResultsGroup C had significantly higher proportions of patients who developed shivering (21), developed grade IV shivering (20) and required meperidine (21) to treat shivering than group M (8,5,5) and group D (5,3,6), which were comparable to each other.The time between block administration and meperidine administration was similar among the three groups. Hypothermia did not occur in any of the patients.The three groups were comparable regarding the occurrence of nausea, vomiting, bradycardia and hypotension. All the patients in group C, 32 patients in group M and 33 patients in group D had a sedation score of 2. Three patients in group M and 2 patients in group D had a sedation score of 3.ConclusionsIntrathecal injections of both dexmedetomidine and magnesium sulfate were effective in reducing the incidence of post-spinal anaesthesia shivering. Therefore, we encourage the use of magnesium sulfate, as it is more physiologically available, more readily available in most operating theatres and much less expensive than dexmedetomidine.Trial registrationClinical trial registration ID: Pan African Clinical Trial Registry (PACTR) Trial Number PACTR201801003001727; January 2018, “retrospectively registered”.

Seven days of cold acclimation substantially reduces shivering intensity and increases nonshivering thermogenesis in adult humans.

Daily compensable cold exposure in humans reduces shivering by ~20% without changing total heat production, partly by increasing brown adipose tissue thermogenic capacity and activity. Although acclimation and acclimatization studies have long suggested that daily reductions in core temperature are essential to elicit significant metabolic changes in response to repeated cold exposure, this has never directly been demonstrated. The aim of the present study is to determine whether daily cold-water immersion, resulting in a significant fall in core temperature, can further reduce shivering intensity during mild acute cold exposure. Seven men underwent 1 h of daily cold-water immersion (14°C) for seven consecutive days. Immediately before and following the acclimation protocol, participants underwent a mild cold exposure using a novel skin temperature clamping cold exposure protocol to elicit the same thermogenic rate between trials. Metabolic heat production, shivering intensity, muscle recruitment pattern, and thermal sensation were measured throughout these experimental sessions. Uncompensable cold acclimation reduced total shivering intensity by 36% (P = 0.003), without affecting whole body heat production, double what was previously shown from a 4-wk mild acclimation. This implies that nonshivering thermogenesis increased to supplement the reduction in the thermogenic contribution of shivering. As fuel selection did not change following the 7-day cold acclimation, we suggest that the nonshivering mechanism recruited must rely on a similar fuel mixture to produce this heat. The more significant reductions in shivering intensity compared with a longer mild cold acclimation suggest important differential metabolic responses, resulting from an uncompensable compared with compensable cold acclimation. NEW & NOTEWORTHY Several decades of research have been dedicated to reducing the presence of shivering during cold exposure. The present study aims to determine whether as little as seven consecutive days of cold-water immersion is sufficient to reduce shivering and increase nonshivering thermogenesis. We provide evidence that whole body nonshivering thermogenesis can be increased to offset a reduction in shivering activity to maintain endogenous heat production. This demonstrates that short, but intense cold stimulation can elicit rapid metabolic changes in humans, thereby improving our comfort and ability to perform various motor tasks in the cold. Further research is required to determine the nonshivering processes that are upregulated within this short time period.

Effects of 0.5% heavy bupivacaine at room versus body temperature on shivering and analgesia after spinal anesthesia in patients undergoing cesarean section

Background: Shivering is an undesirable, unpleasant experience after spinal anesthesia. Injecting cold bupivacaine has been incriminated as a contributory factor. Aims and Objective: In this prospective study we evaluated the efficacy of warming the heavy bupivacaine to body temperature for prevention of shivering and if it influences analgesic quality of spinal anesthesia. Materials and Methods: In this double blind, randomized controlled study, 100 patients aged 20-35 years of American Society of Anesthesiologist physical status I and II undergoing elective or emergency Caesarean sections were included and allocated to either Room temperature group (RT Group, n= 50), or Body temperature group (BT group, n = 50). A standard spinal anesthetic of 2ml of 0.5 % heavy bupivacaine plus 20 microgram of fentanyl was administered using 25G pencil point spinal needle in the sitting position. Besides the incidence and intensity of shivering and effect on intraoperative analgesia, effect on hemodynamics, nausea, vomiting, blood loss, pruritis and Apgar scores were recorded. Data was analyzed using SPSS (The Statistical Package for Social Sciences) version 22.0 software (International Business Machines Corporation, Armonk, New York, USA). P < 0.05 was considered significant. Results: The patients were comparable in terms of demographic variables. Shivering was present in 31 (62%) and 7 (14%) patients respectively in RT and BT Groups, which was statistically significant (P = 0.0001). Intensity of shivering ≥3 was observed in 15 (30%) patients of RT group and 5 (10%) patient in BT group. We did not note any difference in the analgesic status intraoperatively nor any difference in the duration of analgesia. Surprisingly, the incidence of pruritis was significantly reduced in the BT group as compared to RT group (P = 0.037). Conclusions: Warming the heavy bupivacaine to body temperature is effective in preventing shivering and reducing pruritis secondary to spinal anesthesia without affecting analgesia.

Antishivering Effect of Dexmedetomidine on Patients Undergoing Video-Assisted Thoracoscopic Wedge Resection

Background: Post-anesthetic shivering can cause post- surgical pain or discomfort, and create oxygen supply/demand imbalance. Objectives: The current study aimed at evaluating the effects of Dexmedetomidine on the incidence and intensity of shivering and core temperature after general anesthesia. Methods: The current randomized, double-blind, placebo-controlled, clinical trial was conducted at a single center (Gil Medical Center, Incheon, South Korea) from January to December 2016 with convenience sampling and simple random allocation. A total of 40 patients undergoing video-assisted thoracoscopic (VATS) wedge resection were randomly assigned to receive either 1 µg/kg of Dexmedetomidine (Dexmedetomidine group, n = 20) or normal saline (control group, n = 20) 10 minutes after skin incision. Hemodynamic variables and esophageal and tympanic temperatures were recorded five minutes after anesthetic induction, five minutes after achieving a lateral position, every five minutes after carbon dioxide insufflation to the thoracic cavity, and at the end of surgery. Incidences and intensities of post-anesthetic shivering, and postoperative pain scores were recorded. Results: Median postoperative pain score was significantly lower in the Dexmedetomidine group than the control group (4 (0 - 5) vs. 5 (3.25 - 6) (median (interquartile range)), P = 0.004). In the post-anesthetic care unit (PACU), the incidence of shivering was significantly lower in the Dexmedetomidine group than in the control group (0/20 (0%) vs. 6/20 (30%), P = 0.020); but the incidence of hypothermia was higher in the Dexmedetomidine group than in the control group (6/20 (30%) vs. 0/20 (0%), P = 0.020). Conclusions: A single intraoperative dose of Dexmedetomidine (1 µg/kg) may reduce postoperative shivering and pain scores, but it might also increase the incidence of postoperative hypothermia in patients undergoing Sevoflurane anesthesia for video-assisted thoracoscopic wedge resection.

Intrathecal Tramadol for Prevention of Postanesthesia Shivering after Subarachnoid Block: A Prospective Randomized Placebo-Controlled Comparison of Two Different Doses (10 and 20 mg).

Background:Shivering is a common and distressing complication following subarachnoid block (SAB). Literature comparing the antishivering efficacy of different doses of intrathecal (IT) tramadol is lacking.Aims:This prospective randomized controlled study was undertaken to evaluate and compare the antishivering efficacy of IT tramadol 10 and 20 mg.Methods:Ninety adult patients undergoing lower limb orthopedic surgeries under SAB were randomized into three groups (n = 30) to receive IL 0.5% hyperbaric bupivacaine 3 ml with tramadol 0 mg (Group C), 10 mg (Group T10), or 20 mg (Group T20) in normal saline. Shivering was assessed using a 5-point intensity scoring system intraoperatively and up to 4-h postoperatively. The onset and duration of sensory and motor block, duration of analgesia, and adverse effects were assessed.Statistical Analysis Used:Analysis of variance and Pearson Chi-square test were used for statistical analysis.Results:The incidence and intensity of shivering were significantly reduced in Group T10 versus C (incidence, P = 0.007; intensity, P = 0.002) and T20 versus C (incidence, P < 0.001; intensity, P < 0.001) but comparable among groups T10 and T20 (incidence, P = 0.133; intensity, P = 0.142). There was a significant dose-dependent prolongation of duration of sensory block (121, 137, and 150.5 min; P = 0.001), motor block (242.83, 298.5, and 344 min; P < 0.001), and analgesia (289.17, 357, and 404.67 min; P < 0.001) with escalating doses of IT tramadol, respectively. All the groups were comparable with respect to hemodynamic variables, core temperature, and adverse effects.Conclusion:The addition of tramadol 10 or 20 mg IT to 0.5% hyperbaric bupivacaine for SAB is associated with significant reduction in the incidence and intensity of postanesthesia shivering and prolongation of the duration of postoperative analgesia. Tramadol 20 mg IT compared to 10 mg IT significantly prolonged the duration of postoperative analgesia but failed to demonstrate any significant attenuation of postanesthesia shivering.