Decrease In Core Temperature Research Articles

Cardiac arrest secondary to environmental hypothermia: Incidence and outcomes in an urban emergency department in the Upper Midwestern United States.

Data describing hypothermic cardiac arrest (HCA) outcomes predominantly originate from patients involved in wilderness accidents. We describe the incidence and outcomes of HCA in an urban environment, with a subgroup analysis of patients with witnessed HCA in the prehospital or emergency department (ED) setting. We completed a retrospective, single center cohort analysis of consecutive adult patients with environmental exposure and core body temperature≤32°C. We describe characteristics of this cohort and evaluate the relationship between initial core temperature and occurrence of HCA. 171 patients met eligibility criteria from January 2007 to September 2023. 43 (25%) sustained HCA, including 6/98 (6%) of those with moderate hypothermia (28.01-32°C), 21/55 (38%) with severe hypothermia (24-28°C) and 16/18 (89%) with profound hypothermia (<24°C). Risk of HCA increases 2.06 times (95% CI 1.66 to 2.69) for each 1°C decrease in initial core temperature below 32°C. Among HCA patients, 18/43 (42%) had a witnessed HCA during prehospital (n=8) or ED (n=10) care. The overall survival rate of HCA was 53% but was higher in patients with initial core temperature<28°C versus those >28C (62% vs 0%). Survival of hypothermic patients who experienced their first HCA after arrival in the ED approached that of hypothermic patients without HCA (90% vs 94%). Patients with severe hypothermia secondary to environmental exposure in an urban environment are at high-risk of HCA. Witnessed HCA accounts for a significant portion of HCA patients, and patients with witnessed HCA in an ED setting can achieve excellent outcomes.

Management Inadvertent Hypothermia Perioperative : A Systematic Review

Shivering is a common issue experienced by patients during surgery, caused by exposure to cold operating room air. This loss of body heat can make patients uncomfortable and require more oxygen. The purpose of this study is to evaluate the management of shivering and hypothermia based on literature review. A systematic review was conducted following the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA). The article selection process followed the PICO framework. The population consists of individual patients undergoing surgery with spinal anesthesia. The study included patients who experienced shivering and underwent non-pharmacological interventions for temperature management. Articles published between 2018 and 2024 were searched in four databases: Scopus, EBSCO, ProQuest, and PubMed. The quality of the articles was evaluated using the Joanna Briggs Institute (JBI) format. The initial search identified 270 articles, which were narrowed down to 12 after removing duplicates and reviewing titles and inclusion criteria. In this study, 1326 individuals undergoing surgery were surveyed. To prevent hypothermia and shivering, several non-pharmacological methods can be used, such as pre-warming using forced-air warming, which increases body temperature. Isothermic irrigation was found to reduce the decrease in core temperature and the incidence of shivering. Preoperative warming can be done for durations of 30, 15, and 10 minutes before induction. To conclude, shivering can be prevented by non-pharmacological methods to increase core body temperature so that it will increase patient comfort during surgery. One of the innovations that can be done is by making warm vests

Egg White Diet Induces Severe Allergic Enteritis in an Animal Model Driven by Caspase-3 and Gasdermin C-Mediated Mucosal Alarmin Secretion.

Allergic enteritis is an important phenotype of food allergies. However, there is not a suitable animal model for deeply exploring the natural progression and mechanism of allergic enteritis. In our study, we successfully developed an allergic enteritis animal model by feeding mice with an egg white diet. Following the dietary challenge, allergic mice displayed typical food allergy manifestations, including decreased core temperature, aversion to the allergenic diet, and elevated levels of serum sIgE and mMCP-1. Notably, these dietary challenged mice exhibited severe gut damage, characterized by disrupted intestinal microstructure, tissue inflammation, and edema that were evident morphologically. Moreover, upon exposure to food allergens, we observed a marked increase in caspase-3 and GSDMC levels in allergic mice. These two active proteins were found to be colocalized in damaged mucosal enterocytes and were associated with the secretion of epithelial sourced alarmins, such as IL25 and TSLP. Further data on the cellular and molecular levels suggest that such severe food-induced enteritis is mediated by the caspase-3-GSDMC pathway. We believe that this established animal model provides a valuable tool for advancing research on the mechanisms of food allergies.

Modern CRRT systems are associated with lower risk of hypothermia.

One risk of continuous renal replacement therapy (CRRT) is inadvertent hypothermia (IH), which is defined as a non-therapeutic core temperature decrease below normal. In continuous renal replacement therapy, heat loss will always occur from blood pumped through the dialysis circuit to cooler environment, predisposing for hypothermia. Blood flow and effluent flows are the most important parameters causing heat loss. We investigated and compared the novel TherMax warmer to previous generation technologies during CRRT in a multicenter setting. This was a prospective observational multicenter study with historic single-center controls. The study group consisted of 100 patients in eight Swedish ICUs with clinical indication for CRRT, using the PrisMax platform and TherMax warmer. Both patient and set warmer temperatures were recorded hourly for the first 24h. The presence of treatment hours in hypothermia (< 36.0 Celsius) and the difference between set warmer temperature and measured patient temperature in the multi-center study cohort were compared to a matched single-center historic control cohort treated with the old Prismaflex platform and adjacent Barkey warmer. In the TherMax group 77/100 (77.0%) of patients, and for controls 26/86 (30.2%) of patients were free of hypothermia (Chi square, p < 0.001). The mean number of hours spent in hypothermia was (mean ± SD) 0.66 ± 1.60 and 6.92 ± 7.79h in the TherMax and control groups, respectively (Chi square p < 0.001).In the study group the patient temperature was higher than the set temperature on the warmer with a difference of Δ0.47 ± 0.80°C (minor difference), whereas in the control group the set temperature on the warmer was higher than the patient temperature with a difference of Δ4.55 ± 1.00°C (over-correction).The novel TherMax warmer technology protected against hypothermia and was significantly more accurate than the Barkey warmer.

Acute moderate normobaric hypoxia does not modify circulating thyroid hormone concentrations induced by 1 h of head-out cold-water immersion.

This study tested the hypothesis that acute moderate normobaric hypoxia augments circulating thyroid hormone concentrations during and following 1 h of cold head-out water immersion (HOWI), compared with when cold HOWI is completed during normobaric normoxia. In a randomized crossover single-blind design, 12 healthy adults (27 ± 2 yr, 2 women) completed 1 h of cold (22.0 ± 0.1°C) HOWI breathing either normobaric normoxia ([Formula: see text] = 0.21) or normobaric hypoxia ([Formula: see text] = 0.14). Free and total thyroxine (T3) and triiodothyronine (T4), and thyroid-stimulating hormone (TSH) concentrations were measured in venous blood samples obtained before (baseline), during (15-, 30-, and 60 min), and 15 min following HOWI (post-), and were corrected for changes in plasma volume. Arterial oxyhemoglobin saturation and core (rectal) temperature were measured continuously. Arterial oxyhemoglobin saturation was lower during hypoxia (90 ± 3%) compared with normoxia (98 ± 1%, P < 0.001). Core temperature fell from baseline (normoxia: 37.2 ± 0.4°C, hypoxia: 37.2 ± 0.4°C) to post-cold HOWI (normoxia: 36.4 ± 0.5°C, hypoxia: 36.3 ± 0.5°C, P < 0.001) in both conditions but did not change differently between conditions (condition × time: P = 0.552). Circulating TSH, total T3, free T4, total T3, and free T4 concentrations demonstrated significant main effects of time (all P ≤ 0.024), but these changes did not differ between normoxic and hypoxic conditions (condition × time: all P ≥ 0.163). These data indicate that acute moderate normobaric hypoxia does not modify the circulating thyroid hormone response during 1 h of cold HOWI.NEW & NOTEWORTHY Acute head-out cold (22°C) water immersion (HOWI) decreased core temperature and increased thermogenesis. This thermogenic response was paralleled by the activation of the hypothalamic-pituitary-thyroid axis, as evidenced by changes in thyroid hormones. However, cold HOWI in combination with moderate normobaric hypoxia did not modify the thermogenic nor the circulating thyroid hormone response. This finding suggests that hypoxia-induced alterations in thyroid hormone concentrations are unlikely to acutely contribute to adaptations resulting from repeated cold-water exposures.

Alpha-2-adrenergic agonists reduce resting energy expenditure in humans during external cooling

ABSTRACT Intravenous alpha-2-adrenergic receptor agonists reduce energy expenditure and lower the temperature when shivering begins in humans, allowing a decrease in core body temperature. Because there are few data about similar effects from oral drugs, we tested whether single oral doses of the sedative dexmedetomidine (1 µg/kg sublingual or 4 µg/kg swallowed) or the muscle relaxant tizanidine (8 mg or 16 mg), combined with surface cooling, reduce energy expenditure and core body temperature in humans. A total of 26 healthy participants completed 41 one-day laboratory studies measuring core body temperature using an ingested telemetry capsule and measuring energy expenditure using indirect calorimetry for up to 6 hours after drug ingestion. Dexmedetomidine induced a median 13% – 19% peak reduction and tizanidine induced a median 15% – 22% peak reduction in energy expenditure relative to baseline. Core body temperature decreased a median of 0.5°C – 0.6°C and 0.5°C – 0.7°C respectively. Decreases in temperature occurred after peak reductions in energy expenditure. Energy expenditure increased with a decrease in core temperature in control participants but did not occur after 4 µg/kg dexmedetomidine or 16 mg tizanidine. Plasma levels of dexmedetomidine but not tizanidine were related to mean temperature change. Decreases in heart rate, blood pressure, respiratory rate, cardiac stroke volume index, and cardiac index were associated with the change in metabolic rate after higher drug doses. We conclude that both oral dexmedetomidine and oral tizanidine reduce energy expenditure and allow decrease in core temperature in humans.

INTERPLAY BETWEEN BRAIN OXYGENATION AND THE DEVELOPMENT OF HYPOTHERMIA IN ENDOTOXIC SHOCK.

There is evidence to suggest that the hypothermia observed in the most severe cases of systemic inflammation or sepsis is a regulated response with potential adaptive value, but the mechanisms involved are poorly understood. Here, we investigated the interplay between brain oxygenation (assessed by tissue P o2 ) and the development of hypothermia in unanesthetized rats challenged with a hypotension-inducing dose of bacterial LPS (1 mg/kg i.v.). At an ambient temperature of 22°C, oxygen consumption (V̇O 2 ) began to fall only a few minutes after the LPS injection, and this suppression in metabolic rate preceded the decrease in core temperature. No reduction in brain P o2 was observed prior to the development of the hypometabolic, hypothermic response, ruling out the possibility that brain hypoxia served as a trigger for hypothermia in this model. Brain P o2 was even increased. Such an improvement in brain oxygenation could reflect either an increased O 2 delivery or a decreased O 2 consumption. The former explanation seems unlikely because blood flow (cardiac output) was being progressively decreased during the recording period. On the other hand, the decrease in V̇O 2 usually preceded the rise in P o2 , and an inverse correlation between V̇O 2 and brain P o2 was consistently observed. These findings do not support the existence of a closed-loop feedback relationship between brain oxygenation and hypothermia in systemic inflammation. The data are consistent with a feedforward mechanism in which hypothermia is triggered (possibly by cryogenic inflammatory mediators) in anticipation of changes in brain oxygenation to prevent the development of tissue hypoxia.

Precooling via immersion in CO2-enriched water at 25°C decreased core body temperature but did not improve 10-km cycling time trial in the heat

ABSTRACT This study compared the effects of precooling via whole-body immersion in 25°C CO2-enriched water (CO2WI), 25°C unenriched water (WI) or no cooling (CON) on 10-km cycling time trial (TT) performance. After 30 min of precooling (CO2WI, CON, WI) in a randomized, crossover manner, 11 male cyclists/triathletes completed 30-min submaximal cycling (65%VO2peak), followed by 10-km TT in the heat (35°C, 65% relative humidity). Average power output and performance time during TT were similar between conditions (p = 0.387 to 0.833). Decreases in core temperature (Tcore) were greater in CO2WI (−0.54 ± 0.25°C) than in CON (−0.32 ± 0.09°C) and WI (−0.29 ± 0.20°C, p = 0.011 to 0.022). Lower Tcore in CO2WI versus CON was observed at 15th min of exercise (p = 0.050). Skin temperature was lower in CO2WI and WI than in CON during the exercise (p < 0.001 to 0.031). Only CO2WI (1029 ± 305 mL) decreased whole-body sweat loss compared with CON (1304 ± 246 mL, p = 0.029). Muscle oxygenation by near-infrared spectroscopy (NIRS), thermal sensation, and thermal comfort were lower in CO2WI and WI versus CON only during precooling (p < 0.001 to 0.041). NIRS-derived blood volume was significantly lower in CO2WI and WI versus CON during exercise (p < 0.001 to 0.022). Heart rate (p = 0.998) and rating of perceived exertion (p = 0.924) did not differ between conditions throughout the experiment. These results suggested that CO2WI maybe more effective than WI for enhanced core body cooling and minimized sweat losses.

Temperature-Dependent Relationship of Autophagy and Apoptotic Signaling During Cold-Water Immersion in Young and Older Males.

Autophagy is a crucial cytoprotective mechanism preventing the accumulation of cellular damage, especially during external stimuli such as cold exposure. Older adults poorly tolerate cold exposure and age-related impairments in autophagy may contribute to the associated reductions in cold tolerance. The purpose of this investigation is to evaluate the effect of different intensities of in vivo cold-water immersion and in vitro cold exposure on autophagic and apoptotic signaling in young and older males. Peripheral blood mononuclear cells (PBMCs) are isolated at baseline, end-cold exposure, and after 3h of thermoneutral recovery. Additionally, PBMCs are treated with rapamycin and bafilomycin prior to in vitro cold exposure equivalent to in vivo core temperatures (35-37°C). Proteins associated with autophagy, apoptosis, the heat shock response, and inflammation are analyzed via Western blotting. Moderate cold stress (0.5°C decrease in core temperature) increased autophagic and heat shock protein activity while high cold stress (1.0°C decrease in core temperature) augmented apoptosis in young males. In older males, minimal autophagic activation during both cold-water exposures are associated with increased apoptotic and inflammatory proteins. Although in vitro cold exposure confirmed age-related dysfunction in autophagy, rapamycin-induced stimulation of autophagic proteins underlie the potential to reverse age-related vulnerability to cold exposure.

Cerebral Lactate Participates in Hypoxia-induced Anapyrexia Through its Receptor G Protein-coupled Receptor 81

Hypoxia-induced anapyrexia is thought to be a regulated decrease in body core temperature (Tcore), but the underlying mechanism remains unclear. Recent evidence suggests that lactate, a glycolysis product, could modulate neuronal excitability through the G protein-coupled receptor 81 (GPR81). The present study aims to elucidate the role of central lactate and GPR81 in a rat model of hypoxia-induced anapyrexia. The findings revealed that hypoxia (11.1% O2, 2 h) led to an increase in lactate in cerebrospinal fluid (CSF) and a decrease in Tcore. Injection of dichloroacetate (DCA, 5 mg/kg, 1 μL), a lactate production inhibitor, to the third ventricle (3 V), alleviated the increase in CSF lactate and the decrease in Tcore under hypoxia. Immunofluorescence staining showed GPR81 was expressed in the preoptic area of hypothalamus (PO/AH), the physiological thermoregulation integration center. Under normoxia, injection of GPR81 agonist 3-chloro-5-hydroxybenzoic acid (CHBA, 0.05 mg/kg, 1 μL) to the 3 V, reduced Tcore significantly. In addition, hypoxia led to a dramatic increase in tail skin temperature and a decrease in interscapular brown adipose tissue skin temperature. The number of c-Fos+ cells in the PO/AH increased after exposure to 11.1% O2 for 2 h, but administration of DCA to the 3 V blunted this response. Injection of CHBA to the 3 V also increased the number of c-Fos+ cells in the PO/AH under normoxia. In light of these, our research has uncovered the pivotal role of central lactate-GPR81 signaling in anapyrexia, thereby providing novel insights into the mechanism of hypoxia-induced anapyrexia.

Mini-HoLEP (MILEP) vs HoLEP: a propensity score-matched analysis.

Minimal invasiveness improves outcome in many surgical fields including urology. We aimed to assess intraoperative performance and clinical outcome of miniaturized holmium laser enucleation of prostate (MiLEP) (22FR). We ran a propensity score-matched analysis among all consecutive laser enucleations of prostate performed between 9/2022 and 2/2023. It resulted in two matched comparison groups: MiLEP 22 FR (n = 40) and holmium laser enucleation of prostate (HoLEP 26 Fr) (n = 40). Statistical analysis was performed. MiLEP was associated with significantly less intraoperative irrigation (20.5 L vs 15 L,p = 0.002E-3), less decrease in body core temperature (0.6°C vs 0.1°C,p = 0.003E-5), and less need for meatal dilation (25% vs 78%,p = 0.01E-3). These parameters were identified as being independent in the multivariate analysis. There was a trend toward less and a shorter period of postoperative stress incontinence (SI) for the MiLEP group compared to the HoLEP group: 15% and 42% (p = 0.01) at 1 month, 8% and 14% (p = 0.07) at 2 months, and 0 and 0.3% (p = 1) at 3 months, respectively. There were no differences in prostatic enucleation effectiveness, operative time, hospital stay, complications, and improvement in the international prostate symptom score and quality of life score. MiLEP is feasible and provides better maintenance of body core temperature, reduction in amount of fluid irrigation, and decrease in need for meatal dilation without affecting effectiveness in comparison with HoLEP. MiLEP may reduce early postoperative stress incontinence, thereby shortening the recovery period.

Metabolic Manipulation and Therapeutic Hypothermia.

Hypothermia has multiple physiological effects, including decreasing metabolic rate and oxygen consumption (VO2). There are few human data about the magnitude of change in VO2 with decreases in core temperature. We aimed to quantify to magnitude of reduction in resting VO2 as we reduced core temperature in lightly sedated healthy individuals. After informed consent and physical screening, we cooled participants by rapidly infusing 20 mL/kg of cold (4°C) saline intravenously and placing surface cooling pads on the torso. We attempted to suppress shivering using a 1 mcg/kg intravenous bolus of dexmedetomidine followed by titrated infusion at 1.0 to 1.5 μg/(kg·h). We measured resting metabolic rate VO2 through indirect calorimetry at baseline (37°C) and at 36°C, 35°C, 34°C, and 33°C. Nine participants had mean age 30 (standard deviation 10) years and 7 (78%) were male. Baseline VO2 was 3.36 mL/(kg·min) (interquartile range 2.98-3.76) mL/(kg·min). VO2 was associated with core temperature and declined with each degree decrease in core temperature, unless shivering occurred. Over the entire range from 37°C to 33°C, median VO2 declined 0.7 mL/(kg·min) (20.8%) in the absence of shivering. The largest average decrease in VO2 per degree Celsius was by 0.46 mL/(kg·min) (13.7%) and occurred between 37°C and 36°C in the absence of shivering. After a participant developed shivering, core body temperature did not decrease further, and VO2 increased. In lightly sedated humans, metabolic rate decreases around 5.2% for each 1°C decrease in core temperature from 37°C to 33°C. Because the largest decrease in metabolic rate occurs between 37°C and 36°C, subclinical shivering or other homeostatic reflexes may be present at lower temperatures.

A Systematic Review of Post-Work Core Temperature Cooling Rates Conferred by Passive Rest.

Physical work increases energy expenditure, requiring a considerable elevation of metabolic rate, which causes body heat production that can cause heat stress, heat strain, and hyperthermia in the absence of adequate cooling. Given that passive rest is often used for cooling, a systematic search of literature databases was conducted to identify studies that reported post-work core temperature cooling rates conferred by passive rest, across a range of environmental conditions. Data regarding cooling rates and environmental conditions were extracted, and the validity of key measures was assessed for each study. Forty-four eligible studies were included, providing 50 datasets. Eight datasets indicated a stable or rising core temperature in participants (range 0.000 to +0.028 °C min-1), and forty-two datasets reported reducing core temperature (-0.002 to -0.070 °C min-1) during passive rest, across a range of Wet-Bulb Globe Temperatures (WBGT). For 13 datasets where occupational or similarly insulative clothing was worn, passive rest resulted in a mean core temperature decrease of -0.004 °C min-1 (-0.032 to +0.013 °C min-1). These findings indicate passive rest does not reverse the elevated core temperatures of heat-exposed workers in a timely manner. Climate projections of higher WBGT are anticipated to further marginalise the passive rest cooling rates of heat-exposed workers, particularly when undertaken in occupational attire.

A comparison between heat and temperate-cool environment regarding changes in core temperature with regular exercise: A meta-analysis of randomized controlled trials

Purpose: Previous several meta-analyses reported that regular exercise decreased core temperature. However, those meta-analyses included non-randomized controlled trials and did not consider a difference in environment. This meta-analysis aimed to limit studies to randomized controlled trials (RCTs) and evaluate the differences in effects of regular exercise under heat and cool environment on core temperature. Methods: Inclusion criteria were RCTs involving healthy adults, performing exercise in heat index (HI; according to National Weather Service) ≥27°C as the heat environment group (HEAT) and in HI &lt;27°C as the temperate-cool environment group (NORMAL), performing same exercise protocol on both groups, and reporting core temperature at rest or the end of exercise tests. In statistical analyses, the mean differences ([mean value at postintervention in the HEAT – mean value at baseline in the HEAT] – [mean value at postintervention in the NORMAL – mean value at baseline in the NORMAL]) in core temperature were converted into the Hedges’ g values; these values were pooled, and heterogeneity (i.e., a difference among RCTs) was assessed using a Q value. Results: RCTs evaluating core temperature at rest and the end of exercise tests were 5 studies (100 subjects; mean age, 22 to 28 years) and 7 studies (128 subjects; age, 21 to 28 years), respectively. The duration of intervention ranged from 3 to 12 days. Results of the meta-analyses indicated that the pooled g value in core temperature at rest did not decrease significantly (-0.08 [95% confidence interval: -0.18 to 0.03]), and significant heterogeneity was not contained (Q=8.9; P=0.11); in addition, that the pooled g value in core temperature at the end of exercise tests decreased significantly (-0.63 [95% confidence interval: -1.24 to -0.02]), but significant heterogeneity was contained (Q=18.0; P&lt;0.01). Conclusions: The present study is a finding with few RCTs but indicates that regular exercise under heat environment decreases core temperature at the end of exercise than that under normal environment. However, since the results of the meta-analysis contained heterogeneity, the effect may also depend on other factors. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

A study on the effect of preoperative warming on post-induction core temperature and incidence of postoperative shivering in patients under general anesthesia

BackgroundInadvertent perioperative hypothermia (IPH) defined as core temperature below 36.0 °C is a common complication of general anesthesia with prevalence up to 70%. Warming of peripheral tissues prior to induction of anesthesia reduces the central to peripheral temperature gradient, thereby minimizing central heat loss due to heat redistribution, after induction of anesthesia. This study aimed to evaluate the effect of prewarming on post-induction core temperature and incidence of perioperative inadvertent hypothermia leading to postanesthetic shivering (PAS) in patients undergoing general anesthesia.This is a single-arm study performed after authorization from the scientific review committee (IRB no.:10/2015/05) in a cohort of patients between the ages of 18 and 65 years in ASA I and II physical status, undergoing GA for elective surgeries lasting less than 3 h. Rates of IPH and PAS in 60 patients who were warmed before anesthesia over a 30-min period with a forced-air warmer set at 38.0 °C were compared with existing data from an equal number of cohorts who received only intraoperative warming, during similar surgical procedures according to routine GA.Comparisons between the two groups were made using the Student’s t-test and chi-square test. A paired t-test or Wilcoxon’s signed rank test was applied for pairwise comparisons. The results were considered statistically significant when the P-value was < 0.05.ResultsThe mean decrease in core temperature in the unwarmed group was 0.7 °C (+ /- 0.23) compared with a 0.2 °C decrease (+ /- 0.06) in the prewarmed group of patients. A total of 31.70% of patients in the unwarmed group developed IPH compared with one patient (1.7%) in the prewarmed group shortly after onset. Twenty-six patients (43.30%) in the unwarmed group had hypothermia at the end of surgery, compared with one patient (1.7%) in the prewarmed group. Shivering was observed in 46% of patients in the unwarmed group, while no shivering was observed in the prewarmed group.ConclusionsPreoperative warming is an effective intervention to reduce the frequency of core temperature drops after induction of anesthesia, thereby preventing inadvertent perioperative hypothermia and the incidence of postoperative shivering.

Short-term heat acclimation protocols for an aging population: Systematic review.

Elderly and sedentary individuals are particularly vulnerable to heat related illness. Short-term heat acclimation (STHA) can decrease both the physical and mental stress imposed on individuals performing tasks in the heat. However, the feasibility and efficacy of STHA protocols in an older population remains unclear despite this population being particularly vulnerable to heat illness. The aim of this systematic review was to investigate the feasibility and efficacy of STHA protocols (≤twelve days, ≥four days) undertaken by participants over fifty years of age. Academic Search Premier, CINAHL Complete, MEDLINE, APA PsycInfo, and SPORTDiscus were searched for peer reviewed articles. The search terms were; (heat* or therm*) N3 (adapt* or acclimati*) AND old* or elder* or senior* or geriatric* or aging or ageing. Only studies using primary empirical data and which included participants ≥50 years of age were eligible. Extracted data includes participant demographics (sample size, gender, age, height, weight, BMI and [Formula: see text]), acclimation protocol details (acclimation activity, frequency, duration and outcome measures taken) and feasibility and efficacy outcomes. Twelve eligible studies were included in the systematic review. A total of 179 participants took part in experimentation, 96 of which were over 50 years old. Age ranged from 50 to 76. All twelve of the studies involved exercise on a cycle ergometer. Ten out of twelve protocols used a percentage of [Formula: see text] or [Formula: see text] to determine the target workload, which ranged from 30% to 70%. One study-controlled workload at 6METs and one implemented an incremental cycling protocol until Tre was reached +0.9°C. Ten studies used an environmental chamber. One study compared hot water immersion (HWI) to an environmental chamber while the remaining study used a hot water perfused suit. Eight studies reported a decrease in core temperature following STHA. Five studies demonstrated post-exercise changes in sweat rates and four studies showed decreases in mean skin temperature. The differences reported in physiological markers suggest that STHA is viable in an older population. There remains limited data on STHA in the elderly. However, the twelve studies examined suggest that STHA is feasible and efficacious in elderly individuals and may provide preventative protection to heat exposures. Current STHA protocols require specialised equipment and do not cater for individuals unable to exercise. Passive HWI may provide a pragmatic and affordable solution, however further information in this area is required.

Central angiotensin 1-7 triggers brown fat thermogenesis.

We tested the hypothesis that third ventricular (3V) injections of angiotensin 1-7 (Ang 1-7) increases thermogenesis in brown adipose tissue (BAT), and whether the Mas receptor mediates this response. First, in male Siberian hamsters (n= 18), we evaluated the effect of Ang 1-7 in the interscapular BAT (IBAT) temperature and, using selective Mas receptor antagonist A-779, the role of Mas receptor in this response. Each animal received 3V injections (200 nL), with 48 h intervals: saline; Ang 1-7 (0.03, 0.3, 3, and 30 nmol); A-779 (3nmol); and Ang 1-7 (0.3nmol) + A-779 (3nmol). IBAT temperature increased after 0.3nmol Ang 1-7 compared with Ang 1-7+ A-779 at 20, 30, and 60 min. Also, 0.3nmol Ang 1-7 increased IBAT temperature at 10 and 20 min, and decreased at 60 min compared with pretreatment. IBAT temperature decreased after A-779 at 60 min and after Ang 1-7+ A-779 at 30 and 60 min compared with the respective pretreatment. A-779 and Ang 1-7+ A-779 decreased core temperature at 60 min compared with 10min. Then, we evaluated blood and tissue Ang 1-7 levels, and the expression of hormone-sensitive lipase (HSL) and adipose triglyceride lipase (ATGL) in IBAT. Male Siberian hamsters (n= 36) were killed 10min after one of the injections. No changes were observed in blood glucose, serum and IBAT Ang 1-7 levels, and ATGL. Ang 1-7 (0.3nmol) increased p-HSL expression compared with A-779 and increased p-HSL/HSL ration compared with other injections. Ang 1-7 and Mas receptor immunoreactive cells were found in brain regions that coincide with the sympathetic nerves outflow to BAT. In conclusion, 3V injection of Ang 1-7 induced thermogenesis in IBAT in a Mas receptor-dependent manner.

Immediate Cooling and Early Decompression for the Treatment of Cervical Spinal Cord Injury: A Safety and Feasibility Study.

Cervical spinal cord injury (SCI) usually results in severe, long-term disability. Early therapeutic hypothermia (33-34°C) has been used to improve outcomes in preclinical studies, but previous clinical studies have commenced cooling after arrival at hospital. The objective of the study is to determine the feasibility and safety of early therapeutic hypothermia initiated by paramedics and maintained for up to 24 hours in hospital in patients with SCI. This is a pilot clinical study. The study was undertaken at Ambulance Victoria and The Alfred Hospital, Victoria, Australia. A total of 17 consecutive patients with suspected acute traumatic cervical SCI were enrolled. Patients with suspected cervical SCI were administered a bolus (up to 20 mL/kg) intravenous (IV) cold (4°C) normal saline in the prehospital phase of care. After hospital admission and spinal imaging, further cooling used IV catheter temperature control or surface cooling. Major complications and long-term outcomes were compared with historical controls admitted to the same center before the study. A decrease in core temperature of 1.1°C was achieved during prehospital care and the target temperature was achieved in 6 hours with mechanical temperature management devices in the hospital. There were no major safety concerns. Patients with motor complete SCI who underwent early decompressive surgery had a favorable rate of partial spinal cord recovery compared with historical controls. Therapeutic hypothermia induced using bolus, large-volume, ice-cold saline prehospital and maintained for 24 hours using mechanical devices appears to be feasible and safe in patients with SCI. Larger trials need to be undertaken to determine whether prehospital cooling combined with early decompressive surgery improves outcomes in patients with complete cervical SCI. Australian and New Zealand Clinical Trials Registry (ACTRN12616001086459).

Gambaran Kestabilan Suhu Tubuh Bayi Baru Lahir Yang Dilakukan Inisisasi Menyusui Dini (IMD) di Ruang Bayi RSU Bahagia Makassar

Hypotermia is a condition in wich the body experiences a decrease in core temperature (body temperature &lt;36,5°C). One simple intervention to keep the baby’s temperature stable is Early Breastfeeding Initiation (EBI). The aim of this study to determine the difference of axillary temperature of newborn between improper EBI group and proper EBI group for 24 hours in RSU Bahagia Makassar. This prospective cohort study was conducted at Aisyiyah Muntilan Hospital. Sixty-two healthy newborns from healthy mothers born in November 2016 who meet the inclusion and exclusion criteria. Subjects were grouped in improper EBI groups (n=32) and proper EBI groups (n=32). Axila temperature measurements were performed at 1st minute, 30th minute, 60th minute, 6th hour, 12th hour, 24th hour. The result of the hypotermic occurrence is more happened on improper EBI than proper EBI. EBI is able to prevent hypothermia during the first 24 hours of newborn life. Infants with proper EBI have a lower risk of hypothermia

Redistributional Hypothermia Prevention by Prewarming with Forced-Air: Exploratory, Open, Randomized, Clinical Trial of Efficacy.

Avoiding redistributional hypothermia that decreases core temperature by 0.5-1.5°C within the 1st hour of surgery is difficult. The efficacy of prewarming using a forced-air warming (FAW) device with a lower-body blanket on redistribution hypothermia during epidural procedures have not been investigated. After ethics approval, 113 patients undergoing laparoscopic surgery under general anesthesia combined with epidural anesthesia were enrolled. Intervention (prewarming) group patients who were warmed from operating room entry, including during epidural anesthesia, was compared with the control group that was warmed from just before surgery started. In total, 104 patients (52, control; 52, prewarming) were analyzed. In the prewarming group, compared to the control group, the core temperature 20 minutes after anesthesia induction (36.9 ± 0.4 vs. 37.1 ± 0.4°C, p < 0.02) was significantly higher. The core temperature was higher in the prewarming group than in the control group until 3 hours after the surgery. In the prewarming group, compared to the control group, the core temperature-time integral below baseline till 180 minutes after surgery start (65.1 ± 64.0 vs. 8.1 ± 18.6°C/min, p < 0.0001) or 30 minutes after anesthesia induction (5.3 ± 6.2 vs. 2.0 ± 4.7°C/min, p < 0.0001) were significantly smaller. Postoperative shivering was comparable between the groups. Prewarming during epidural catheter insertion with a FAW device could safely prevent a core temperature decrease induced by redistribution or heat loss without additional preparation, effort, space, or time requirements.