Non-pharmacological treatments for shivering post neuraxial anaesthesia for caesarean section: a scoping review.

BACKGROUND: Shivering occurs more frequently for women having caesarean section under neuraxial anaesthesia compared to other patient groups and causes an increase in pain and interrupts bonding with her newborn. AIM: This study aimed to report the evidence on non-pharmacological methods to treat shivering, defined as uncontrollable shaking, because of being cold, frightened, or excited, post neuraxial anaesthesia; the use of local anaesthesia inserted around the nerves of the central nervous system such as spinal anaesthesia and epidural in women having a caesarean section. METHODS: A scoping review was conducted using six electronic health databases that were searched with no restrictions placed on language, date, or study type. FINDINGS: Of the 1399 studies identified, following screenings only one study was deemed suitable for inclusion. The study, a randomised controlled trial, compared forced air warming blankets (intervention) with the usual care of warmed cotton blankets (control) and its impact on maternal and newborn outcomes. The only statistically significant difference found was the perceived thermal comfort of the mother. DISCUSSION: Non-pharmacological treatments for shivering are underrepresented in the literature; only one study identified where the impact of active warming was compared to warmed cotton blankets (usual care) for the measures of: oral temperature; degree of shivering; and thermal comfort pain scores. There was a decline in temperature in both groups at odds with some women reporting feeling too warm such that they asked for the active warmer to be turned down. CONCLUSION: Social engagement strategies are interventions that send a signal of safety to the nervous system leading to a sense of calm and wellbeing and have biological plausibility and warrant evaluation. Recommendations for further research: design a robust study to test the effectiveness of social engagement strategies on shivering for women having caesarean section under neuraxial anaesthesia.

Neural circuits of long-term thermoregulatory adaptations to cold temperatures and metabolic demands.

The mammalian brain controls heat generation and heat loss mechanisms that regulate body temperature and energy metabolism. Thermoeffectors include brown adipose tissue, cutaneous blood flow and skeletal muscle, and metabolic energy sources include white adipose tissue. Neural and metabolic pathways modulating the activity and functional plasticity of these mechanisms contribute not only to the optimization of function during acute challenges, such as ambient temperature changes, infection and stress, but also to longitudinal adaptations to environmental and internal changes. Exposure of humans to repeated and seasonal cold ambient conditions leads to adaptations in thermoeffectors such as habituation of cutaneous vasoconstriction and shivering. In animals that undergo hibernation and torpor, neurally regulated metabolic and thermoregulatory adaptations enable survival during periods of significant reduction in metabolic rate. In addition, changes in diet can activate accessory neural pathways that alter thermoeffector activity. This knowledge may be harnessed for therapeutic purposes, including treatments for obesity and improved means of therapeutic hypothermia.

The Effect of Warmed Serum on Shivering and Recovery Period of Patients Under General and Spinal Anesthesia: A Randomized Clinical Trial.

PURPOSE: Postoperative hypothermia followed by shivering is a common phenomenon in patients undergoing surgery under anesthesia, and should be prevented and treated in postoperative patient care units. This study was conducted to investigate the effect of warmed serum injection on postoperative shivering and recovery period of patients operated under general and spinal anesthesia. DESIGN: In this clinical trial, patients to be operated on under general and spinal anesthesia were randomly assigned into two groups of test and control. In the test group, patients received warmed intravenous fluids and blood products. All patients were monitored to record vital signs, incidences of hypothermia and shivering, and recovery period. METHODS: The collected data were analyzed with repeated measures analysis of variance to detect significant differences between groups and significant changes within groups over time. FINDINGS: The incidence of nausea, vomiting, and shivering in the intervention and control groups was (4.7%, 42%), (2.8%, 16.8%), and (6.6%, 43%), respectively. Patients in the intervention group had higher body temperature than the control group (<0.001). Also, patients under spinal anesthesia had higher body temperature than patients under general anesthesia (<0.001). Blood pressure reduction was also significantly higher in the control group than in the intervention group. The patients who received warm intravenous serum, and especially those who had received spinal anesthesia spent less time in the recovery room (<0.001). CONCLUSIONS: The use of warmed intravenous serum increased the patients' core temperature, reduced their postoperative shivering, and shortened their recovery period. Considering the potential risks associated with hypothermia, using such methods for hypothermia prevention can be highly effective in preventing shivering and prolongation of the recovery period and other potential complications. Anesthesia specialists and technicians are therefore encouraged to use this method as a preventive measure.

Droperidol lowers the shivering threshold in rabbits.

PURPOSE: Perioperative shivering is common and can occur as a result of hypothermia or changes in the threshold of thermoregulation. Droperidol usage for anesthesia is currently limited to its sedative and antiemetic effects. We investigated the effects of high and low doses of droperidol on the shivering threshold in rabbits. METHODS: Forty-two male Japanese white rabbits were anesthetized with isoflurane and randomly assigned to the control, high-dose, or low-dose group. Rabbits in the high-dose group received a 5 mg/kg droperidol bolus followed by continuous infusion at 5 mg/kg/h, those in the low-dose group received a 0.5 mg/kg droperidol bolus, and those in the control group received the same volume of saline as the high-dose group. Body temperature was reduced at a rate of 2-3 °C/h, and the shivering threshold was defined as the subject's core temperature (°C) at the onset of shivering. RESULTS: The shivering thresholds in the control, high-dose, and low-dose groups were 38.1 °C ± 1.1 °C, 36.7 °C ± 1.2 °C, and 36.9 °C ± 1.0 °C, respectively. The shivering thresholds were significantly lower in the high-dose and low-dose groups than in the control group (P < 0.01). The thresholds were comparable between the high-dose and low-dose groups. CONCLUSIONS: Droperidol in high and low doses effectively reduced the shivering threshold in rabbits. Droperidol has been used in low doses as an antiemetic. Low doses of droperidol can reduce the incidence of shivering perioperatively and during the induction of therapeutic hypothermia.

Nitrous oxide consistently attenuates thermogenic and thermoperceptual responses to repetitive cold stress in humans.

Divers are at enhanced risk of hypothermia, due to the independent action of the inspired inert gases on thermoregulation. Thus, narcosis induced by acute (≤2 h) exposure to either hyperbaric nitrogen or normobaric nitrous oxide (N2O) impairs shivering thermogenesis and accelerates body core cooling. Animal-based studies, however, have indicated that repeated and sustained N2O administration may prevent N2O-evoked hypometabolism. We, therefore, examined the effects of prolonged intermittent exposure to 30% N2O on human thermoeffector plasticity in response to moderate cold. Fourteen men participated in two ∼12-h sessions, during which they performed sequentially three 120-min cold-water immersions (CWIs) in 20°C water, separated by 120-min rewarming. During CWIs, subjects were breathing either normal air or a normoxic gas mixture containing 30% N2O. Rectal and skin temperatures, metabolic heat production (via indirect calorimetry), finger and forearm cutaneous vascular conductance (CVC; laser-Doppler fluxmetry/mean arterial pressure), and thermal sensation and comfort were monitored. N2O aggravated the drop in rectal temperature (P = 0.01), especially during the first (by ∼0.3°C) and third (by ∼0.4°C) CWIs. N2O invariably blunted the cold-induced elevation of metabolic heat production by ∼22%-25% (P < 0.001). During the initial ∼30 min of the first and second CWIs, N2O attenuated the cold-induced drop in finger (P ≤ 0.001), but not in forearm CVC. N2O alleviated the sensation of coldness and thermal discomfort throughout (P < 0.001). Thus, the present results demonstrate that, regardless of the cumulative duration of gas exposure, a subanesthetic dose of N2O depresses human thermoregulatory functions and precipitates the development of hypothermia.NEW & NOTEWORTHY Human thermoeffector plasticity was evaluated in response to prolonged iterative exposure to 30% N2O and moderate cold stress. Regardless of the duration of gas exposure, N2O-induced narcosis impaired in a persistent manner shivering thermogenesis and thermoperception.

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.

Hypothermia evoked by stimulation of medial preoptic nucleus protects the brain in a mouse model of ischaemia.

Therapeutic hypothermia at 32-34 °C during or after cerebral ischaemia is neuroprotective. However, peripheral cold sensor-triggered hypothermia is ineffective and evokes vigorous counteractive shivering thermogenesis and complications that are difficult to tolerate in awake patients. Here, we show in mice that deep brain stimulation (DBS) of warm-sensitive neurones (WSNs) in the medial preoptic nucleus (MPN) produces tolerable hypothermia. In contrast to surface cooling-evoked hypothermia, DBS mice exhibit a torpor-like state without counteractive shivering. Like hypothermia evoked by chemogenetic activation of WSNs, DBS in free-moving mice elicits a rapid lowering of the core body temperature to 32-34 °C, which confers significant brain protection and motor function reservation. Mechanistically, activation of WSNs contributes to DBS-evoked hypothermia. Inhibition of WSNs prevents DBS-evoked hypothermia. Maintaining the core body temperature at normothermia during DBS abolishes DBS-mediated brain protection. Thus, the MPN is a DBS target to evoke tolerable therapeutic hypothermia for stroke treatment.

Clinical efficacy of short-term prewarming in elderly and adult patients: A prospective observational study.

Background: Short-term prewarming effectively reduces intraoperative hypothermia in adult patients. However, few data exist regarding its efficacy in elderly patients. Elderly people have a reduced ability to regulate their body temperature, which affects the efficacy of prewarming. This study aimed to compare the clinical efficacy of short-term pre-warming in elderly patients with that in adult patients. Methods: We enrolled 25 adult (20-50 years) and 25 elderly (> 65 years) patients scheduled for ureteroscopic stone surgery under general anaesthesia. All patients received preanaesthetic forced-air warming for 20 min. The core temperature was measured using an infrared tympanic thermometer during awakening and nasopharyngeal thermistors during anaesthesia. Incidence and severity of intraoperative hypothermia (< 36°C) was compared. Postoperative shivering and number of patients requiring active warming in the post-anaesthesia care unit were also assessed. Results: Intraoperative hypothermia was more frequent in elderly than in adult patients (58.3% vs. 12.0%; relative risk 2.6; 95% confidence interval 1.5 to 4.6; effect size h = 1.010; p = 0.001). The severity of intraoperative hypothermia showed a significant intergroup difference (p = 0.002). Postoperative shivering was more frequent in elderly than in adult patients (33.3% vs. 8.0%, p = 0.037). A greater number of elderly patients in the post-anaesthesia care unit required active warming (33.3% vs. 8.0%, p = 0.037). Conclusions: The effects of short-term prewarming on the prevention of hypothermia and maintenance of perioperative normothermia are not the same in the elderly and adult patients.

Thermogenic responses to different clamped skin temperatures in cold-exposed men and women.

Despite many decades of research examining thermoregulatory responses under varying cold stresses in humans, very little is known about the variability in metabolic heat production and shivering activity. Here, we used a novel closed-loop mean skin temperature clamping technique with a liquid-conditioned suit to isolate the effects of mean skin temperature on the subjective evaluation of thermal sensation, heat production, shivering responses, and oxidative fuel selection in young, lean, and healthy men (n = 12) and women (n = 12). Our results showed a skin temperature-dependent increase in metabolic heat production (5.2 ± 1.2 kJ/min, 5.9 ± 1.5 kJ/min, and 7.0 ± 1.8 kJ/min with skin temperature maintained at 31 ± 0.1°C, 29 ± 0.2°C, and 27 ± 0.1°C, respectively; P < 0.0001) and shivering intensity in both men and women [0.6 ± 0.1% maximal voluntary contraction (MVC), 1.1 ± 0.4% MVC, and 2.5 ± 0.7% MVC, respectively; P < 0.0001], including sex-dependent differences in heat production at all three temperatures (P < 0.005). Even when controlling for lean body mass and fat mass, sex differences persisted (P = 0.048 and P = 0.004, respectively), whereas controlling for differences in body surface area eliminated these differences. Interestingly, there were no sex differences in the cold-induced change in thermogenesis. Despite clamping skin temperature, there was tremendous variability in the rate of heat production and shivering intensity. Collectively this data suggests that many of the interindividual differences in thermogenesis and shivering may be explained by differences in morphology and body composition.

Effects of a short-term cold exposure on circulating microRNAs and metabolic parameters in healthy adult subjects.

This discovery study investigated in healthy subjects whether a short-term cold exposure may alter circulating microRNAs and metabolic parameters and if co-expression networks between these factors could be identified. This open randomized crossover (cold vs no cold exposure) study with blind end- point evaluation was conducted at 1 center with 10 healthy adult male volunteers. Wearing a cooling vest perfused at 14°C for 2 h reduced the local skin temperature without triggering shivering, increased norepinephrine and blood pressure while decreasing copeptin, C-peptide and heart rate. Circulating microRNAs measured before and after wearing the cooling vest twice (4 time points) identified 196 mature microRNAs with excellent reproducibility over 72 h. Significant correlations of microRNA expression with copeptin, norepinephrine and C-peptide were found. A co-expression-based microRNA-microRNA network, as well as microRNA pairs displaying differential correlation as a function of temperature were also detected. This study demonstrates that circulating miRNAs are differentially expressed and coregulated upon cold exposure in humans, supporting their use as predictive and dynamic biomarkers of cardio-metabolic disorders.

Independent and combined impact of hypoxia and acute inorganic nitrate ingestion on thermoregulatory responses to the cold.

PURPOSE: This study assessed the impact of normobaric hypoxia and acute nitrate ingestion on shivering thermogenesis, cutaneous vascular control, and thermometrics in response to cold stress. METHOD: Eleven male volunteers underwent passive cooling at 10 °C air temperature across four conditions: (1) normoxia with placebo ingestion, (2) hypoxia (0.130 FiO2) with placebo ingestion, (3) normoxia with 13 mmol nitrate ingestion, and (4) hypoxia with nitrate ingestion. Physiological metrics were assessed as a rate of change over 45 min to determine heat loss, and at the point of shivering onset to determine the thermogenic thermoeffector threshold. RESULT: Independently, hypoxia expedited shivering onset time (p = 0.05) due to a faster cooling rate as opposed to a change in central thermoeffector thresholds. Specifically, compared to normoxia, hypoxia increased skin blood flow (p = 0.02), leading to an increased core-cooling rate (p = 0.04) and delta change in rectal temperature (p = 0.03) over 45 min, yet the same rectal temperature at shivering onset (p = 0.9). Independently, nitrate ingestion delayed shivering onset time (p = 0.01), mediated by a change in central thermoeffector thresholds, independent of changes in peripheral heat exchange. Specifically, compared to placebo ingestion, no difference was observed in skin blood flow (p = 0.5), core-cooling rate (p = 0.5), or delta change in rectal temperature (p = 0.7) over 45 min, while nitrate reduced rectal temperature at shivering onset (p = 0.04). No interaction was observed between hypoxia and nitrate ingestion. CONCLUSION: These data improve our understanding of how hypoxia and nitric oxide modulate cold thermoregulation.

Thermoregulation and shivering responses in elite alpine skiers.

This study aimed to characterise the thermoregulatory responses of elite alpine skiers. Core (gastro-intestinal) and skin temperatures were recorded continuously from 4 national team skiers representing 18 training-sessions for a total of 83 ski runs (average ambient temperature 1.9°C). Shivering responses were estimated from quadriceps and hamstrings EMG recordings during 77 chairlifts. Temperature responses were also obtained from 6 accompanying staffs representing 16 training-sessions (passive in 10 cases, following the skiers in 6 cases). Core temperature of the skiers (P < .001) but not the staff (P = .103) increased during training and was higher in skiers than staff after one-third of the training session (P < .006). Conversely, average skin temperature of the skiers decreased during training (P < .001) and was lower in skiers than staff for the second half of the training. Muscle activity during chairlifts remained below 1% and there was no meaningful shivering. Muscle activity decreased whilst mean and median power frequency increased during the chairlift (P < .020). Muscle activity was also lower during the last lift than the first one whilst mean and median power frequency were higher (P < .020). In conclusion, skin temperature decreased during Slalom and Giant Slalom in elite alpine skiers, likely due to the limited insulative capacity of the racing suit and the high velocity increasing convective heat loss. Conversely, core temperature increased during the training session suggesting that the metabolic heat production was larger than the convective heat loss, and was also sufficient to maintain homeostasis without shivering.

Acute basilar artery occlusion with recurrent shivering: A case report.

RATIONALE: Shivering is an important physiological response of the body that causes muscle tremors to maintain temperature homeostasis. Traumatic brain injuries that affect the hypothalamus cause hypothermia, and physical removal of suprasellar tumors causes thermoregulation imbalance. However, no study has reported shivering due to ischemic stroke. PATIENT CONCERNS: A 58-year-old male patient was admitted to our emergency department to evaluate severe stenosis of the basilar artery. While waiting for further examination, he exhibited coarse shivering and severe dysarthria. DIAGNOSIS: Brain computed tomography angiography revealed occlusion of the entire basilar artery, and cerebral hypoperfusion was diagnosed in that area. INTERVENTIONS: Transfemoral cerebral angiography (TFCA) was immediately performed, followed by thrombectomy of the basilar artery. OUTCOMES: Neurological deficits, including shivering, were rapidly reversed. The same symptom reoccurred 5 hours later, and TFCA was performed for thrombectomy and stenting, and neurological symptoms immediately reversed. The patient's neurological symptoms did not worsen during hospitalization. LESSONS: Patients with acute basilar artery occlusion need prompt management because they have a higher mortality rate than those with other intracranial artery occlusions. When a patient exhibits neurological deficits accompanied by abrupt shivering for no specific reason, basilar artery occlusion must be considered.

Multiorgan contribution to non-shivering and shivering thermogenesis and vascular responses during gradual cold exposure in humans.

PURPOSE: Human brown adipose tissue (BAT) is known to be a significant thermoeffector in non-shivering thermogenesis (NST), albeit with individual variations in the BAT activity. We hypothesized that humans with less BAT would have more contribution from the skeletal muscle (SM) to NST or earlier shivering onset and greater vasoconstriction to compensate for less BAT-mediated thermogenesis. METHODS: Eighteen males participated in this study. Their BAT activity and detectable volume were investigated. A gradual cold exposure was conducted for inducing NST at 18.6 °C and initiating shivering at 11.6 °C. The energy expenditure, electromyograph of the pectoralis major, skin blood flow, and rectal (Tre) and skin temperatures were evaluated. RESULTS: BAT volume significantly correlated with the change in metabolic heat production during mild cold phase relative to baseline (NST; r = 0.562, P < 0.05), but not with shivering initiation phase (NST+ ST). SM mass correlated with baseline metabolic heat production (Mbase; r = 0.839, P < 0.01) but not with NST or NST + ST. A positive correlation was noted between BAT volume and Tre at the end of the 18.6 °C exposure period (r = 0.586, P < 0.05), which positively correlated with shivering onset time (r = 0.553, P < 0.05). The skin blood flow, mean skin temperature, and forearm and finger skin temperature difference at the end of the 18.6 °C exposure period did not correlate with NST or BAT volume. CONCLUSION: BAT volume positively correlated with NST. Notably, lower Tre in individuals with less BAT volume induced earlier shivering onset for offsetting the less NST. Whereas, no correlation between metabolic and vasomotor responses was observed.

Safety of intraoperative hypothermia for patients: meta-analyses of randomized controlled trials and observational studies.

BACKGROUND: Previous studies have shown that intraoperative hypothermia was associated with higher risks of clinical adverse events, but we found otherwise from recent evidences. This study aims to synthesize the existing evidence evaluating safety of intraoperative hypothermia. METHODS: Articles, reviews, ongoing trials and grey literatures were retrieved from PubMed, The Cochrane Library, Clinical Trails and CNKI (a Chinese national database) till February 2nd, 2019. Both randomized controlled trials and observational studies compared incidences of all sorts of intra- and post-operative consequences between hypothermia and normothermia were included. Researches comparing different warming systems were excluded. We also examined risks of hypothermia using lowered standards (35.5 °C and 35 °C) from a Chinese trial (ChiCTR-IPR-17011099). RESULTS: A total of 9 RCT studies and 11 observational studies were included. RCT-synthesized results showed that intraoperative hypothermia was associated with higher risks of bleeding (MD = 131.90, 95%CI: 117.42, 146.38), surgical site infection (RD = 0.14, 95%CI: 0.06, 0.21) and shivering (RD = 0.32, 95%CI: 0.06, 0.58) but with no significant differences in duration of surgery, hospital stay or mortality. Observational study-synthesized evidences showed that intraoperative hypothermia did not result in higher risks in any of these adverse events. Results didn't change even if the standard of hypothermia was lowered by 0.5-1.0 °C. CONCLUSIONS: The study indicates that the synthesized risks resulted by intra-operative hypothermia might be overestimated and the eligibility of 36 °C to define hypothermia is not sensitive enough. Given body-temperature protection has not been popularized in China, it is still critical to normalize the hypothermia prevention at this stage.

Effect of intrathecal lipophilic opioids on the incidence of shivering in women undergoing cesarean delivery after spinal anesthesia: a systematic review and bayesian network meta- analysis of randomized controlled trials.

BACKGROUND: Shivering is a common side effect in women having cesarean delivery (CD) under spinal anesthesia, which can be bothersome to the patient, and it can also interfere with perioperative monitoring. In several studies, the intrathecal (IT) addition of a lipophilic opioid to local anesthetics has been shown to decrease the incidence of shivering. OBJECTIVE: We performed this network meta-analysis to evaluate the effects of intrathecal lipophilic opioids in preventing the incidence of shivering in patients undergoing CD. METHODS: This review was planned according to the PRISMA for Network Meta-Analysis (PRISMA-NMA) guidelines. An English literature search of multiple electronic databases was conducted. We included randomized controlled trials (RCTs) that reported on the incidence of shivering, with study groups receiving either IT fentanyl, sufentanil, or meperidine in women undergoing CD under spinal anesthesia. Quality of the studies was assessed using the modified Oxford scoring system. Using random-effects modeling, dichotomous data were extracted and summarized using odds ratio (OR) with a 95% credible interval (CrI). Statistical analysis was conducted using R studio version 1.0.153 - Inc. RESULTS: Twenty-one studies consisting of 1433 patients (Control group: 590 patients in twenty-one studies; Fentanyl group:199 patients in seven studies; Sufentanil group: 156 patients in five studies; Meperidine group: 488 patients in ten studies) met the inclusion criteria for this systematic review investigating the effect of intrathecal lipophilic opioids in preventing the incidence of shivering in women undergoing cesarean delivery under spinal anesthesia. Methodological validity scores ranged from 3 to 7. The Bayesian mixed network estimate showed the incidence of shivering was significantly lower with IT fentanyl (pooled odds ratio (OR): 0.13; 95% credible interval (CrI): 0.04 to 0.35; P = 0.0004) and IT meperidine (OR: 0.12; 95% CrI: 0.05 to 0.29; P < 0.00001), but not with IT sufentanil (OR: 0.37; 95% CrI: 0.11 to 1.22; P = 0.23). The IT fentanyl group had a significantly lower incidence of intraoperative discomfort [Risk Ratio (RR): 0.19; 95% CI: 0.10-0.35; P < 0.00001], the IT sufentanil group had a significantly higher incidence of pruritus (RR: 6.18; 95% CI: 1.18-32.46; P = 0.03) The IT meperidine group had a significantly lower incidence of intraoperative discomfort (2.7% vs. 13.6%; RR: 0.22; 95% CI: 0.09-0.55; P = 0.001), but there was a significant increase in nausea and vomiting (IT meperidine group vs. Control group: 42.7% vs. 19.4%; RR: 2.56; 95% CI: 1.14-5.75; P = 0.02). Meta-regression analysis based on the opioid dose and quality of the study did not impact the final inference of our result. CONCLUSION: IT fentanyl significantly decreased the incidence of shivering in women undergoing CD under spinal anesthesia without increasing maternal adverse events, confirming that routine use in this patient population is a good choice. IT sufentanil did not decrease the incidence of shivering. IT meperidine decreased the incidence and severity of shivering, but its use was also associated with significant nausea and vomiting.

The effect of combination of warm intravenous fluid infusion and forced air warming versus forced air warming alone on maternal temperature and shivering during cesarian delivery under spinal anesthesia.

Objective: Administration of warm intravenous (IV) fluid infusion and use of forced air warmers is the most easy and physiologically viable method for maintaining normothermia during surgery and postsurgical periods This study was conducted to assess the effect of combination of active warming (AW) methods namely warm IV fluid infusion and forced air warming versus forced air warming only (WA) on maternal temperature during elective C-delivery under spinal anesthesia. Materials and Methods: A total of 100 patients scheduled for elective c-section were grouped into those who received both warmed IV fluid infusion and forced air warmer (Combination of active warming WI= 50) and those who received only forced air warmer (WA = 50). Core body temperature and shivering incidence were recorded using a tympanic thermometer from prespinal till the end of surgery every 10 min and in postanesthesia care unit (PACU) at 0, 15, and 30 min. Results: Core temperature showed statistically significant difference in 15, 35, 45, and 55 min between air warmer and warm infusion groups and in PACU at 0, 15, and 30 min, it was statistically significant (P = 0.000) among WI group (mean temperature = 36.79°C) when compared to WA group (mean temperature = 35.96°C). There was a lower incidence of shivering in WI compared to WA group, which is statistically significant. Conclusion: Combination of warm Intravenous fluid infusion and Forced air warming is better than forced air warming alone. In maintaining near normal maternal core body temperature during elective cesarean section following spinal anesthesia. Combined warming method also reduces shivering incidence.

RésuméObjectif: L'administration d'une perfusion de liquide intraveineux chaud (IV) et l'utilisation de réchauffeurs à air forcé sont les plus faciles et les plus viables sur le plan physiologique méthode pour maintenir la normothermie pendant la chirurgie et les périodes post-chirurgicales Cette étude a été menée pour évaluer l'effet de la combinaison des méthodes de réchauffement actif (AW), à savoir la perfusion de liquide IV chaud et le réchauffement à air forcé par rapport au réchauffement à air forcé uniquement (WA) sur la mère la température pendant la livraison élective de C sous anesthésie rachidienne. Matériel et méthodes: Un total de 100 patients programmés pour un stage électif les césariennes ont été regroupées dans celles qui ont reçu à la fois une perfusion de liquide IV chauffée et un réchauffeur à air forcé (combinaison de réchauffement actif WI = 50) et ceux qui n'ont reçu qu'un réchauffeur d'air forcé (WA = 50). La température corporelle centrale et l'incidence des frissons ont été enregistrées en utilisant un thermomètre tympanique du préspinal jusqu'à la fin de la chirurgie toutes les 10 min et dans l'unité de soins postanesthésiques (PACU) à 0, 15 et 30 min. Résultats: La température centrale a montré une différence statistiquement significative en 15, 35, 45 et 55 min entre les groupes de réchauffement de l'air et de perfusion chaude et dans le PACU à 0, 15 et 30 min, il était statistiquement significatif (P = 0,000) dans le groupe WI (température moyenne = 36,79 ° C) en comparaison au groupe WA (température moyenne = 35,96 ° C). Il y avait une incidence plus faible de frissons dans WI par rapport au groupe WA, qui est statistiquement important. Conclusion: La combinaison de la perfusion de liquide intraveineux chaud et du réchauffement forcé de l'air est meilleure que le réchauffement forcé de l'air seul. Dans maintien d'une température corporelle maternelle près de la normale pendant la césarienne élective après anesthésie rachidienne. Réchauffement combiné La méthode réduit également l'incidence des frissons.

Energy Expenditure and Shivering Severity During Targeted Temperature Management at 36°C After Cardiac Arrest: A Case Series.

Patients undergoing targeted temperature management (TTM) after cardiac arrest are at risk for shivering, which increases energy expenditure (EE) and may attenuate TTM benefits. This article reports patterns of EE for patients with and without shivering who received TTM at 36°C after cardiac arrest. Based on 96 case assessments, there were 14 occasions when more than one 15-minute interval period was required to appropriately modify the Bedside Shivering Assessment Scale (BSAS) score. Investigators noted that although higher EE was related to higher BSAS scores, there may be opportunities for earlier detection of shivering.

Beneficial effect of fluid warming in elderly patients with bladder cancer undergoing Da Vinci robotic-assisted laparoscopic radical cystectomy.

OBJECTIVES: The enhanced recovery after surgery (ERAS) protocol recommends prevention of intraoperative hypothermia. However, the beneficial effect of maintaining normothermia after radical cystectomy has not been evaluated. This study aimed to investigate the efficacy of fluid warming nursing in elderly patients undergoing Da Vinci robotic-assisted laparoscopic radical cystectomy. METHODS: A total of 108 patients with bladder cancer scheduled to undergo DaVinci robotic-assisted laparoscopic radical cystectomy were recruited and randomly divided into the control group (n=55), which received a warming blanket (43°C) during the intraoperative period and the warming group (n=53), in which all intraoperative fluids were administered via a fluid warmer (41°C). The surgical data, body temperature, coagulation function indexes, and postoperative complications were compared between the two groups. RESULTS: Compared to the control group, the warming group had significantly less intraoperative transfusion (p=0.028) and shorter hospitalization days (p<0.05). During the entire intraoperative period (from 1 to 6h), body temperature was significantly higher in the warming group than in the control group. There were significant differences in preoperative fibrinogen level, white blood cell count, total bilirubin level, intraoperative lactose level, postoperative thrombin time (TT), and platelet count between the control and warming groups. Multivariate linear regression analysis demonstrated that TT was the only significant factor, suggesting that the warming group had a lower TT than the control group. CONCLUSION: Fluid warming nursing can effectively reduce transfusion requirement and hospitalization days, maintain intraoperative normothermia, and promote postoperative coagulation function in elderly patients undergoing Da Vinci robotic-assisted laparoscopic radical cystectomy.

Autonomic effects induced by pharmacological activation and inhibition of Raphe Pallidus neurons in anaesthetized adult pigs.

The Raphe Pallidus (RPa) is a region of the brainstem that was shown to modulate the sympathetic outflow to many tissues and organs involved in thermoregulation and energy expenditure. In rodents, the pharmacological activation of RPa neurons was shown to increase the activity of the brown adipose tissue, heart rate, and expired CO2 , whereas their inhibition was shown to induce cutaneous vasodilation and a state of hypothermia that, when prolonged, leads to a state resembling torpor referred to as synthetic torpor. If translatable to humans, this synthetic torpor-inducing procedure would be advantageous in many clinical settings. A first step to explore such translatability, has been to verify whether the neurons within the RPa play the same role described for rodents in a larger mammal such as the pig. In the present study, we show that the physiological responses inducible by the pharmacological stimulation of RPa neurons are very similar to those observed in rodents. Injection of the GABAA agonist GABAzine in the RPa induced an increase in heart rate (from 99 to 174 bpm), systolic (from 87 to 170 mm Hg) and diastolic (from 51 to 98 mm Hg) arterial pressure, and end-tidal CO2 (from 49 to 62 mm Hg). All these changes were reversed by the injection in the same area of the GABAA agonist muscimol. These results support the possibility for RPa neurons to be a key target in the research for a safe and effective procedure for the induction of synthetic torpor in humans.