ß-adrenergic stimulation after rewarming does not mitigate hypothermia-induced contractile dysfunction in rat cardiomyocytes.

Victims of severe accidental hypothermia are frequently treated with catecholamines to counteract the hemodynamic instability associated with hypothermia-induced cardiac contractile dysfunction. However, we previously reported that the inotropic effects of epinephrine are diminished after hypothermia and rewarming (H/R) in an intact animal model. Thus, the goal of this study was to investigate the effects of Epi treatment on excitation-contraction coupling in isolated rat cardiomyocytes after H/R. In adult male rats, cardiomyocytes isolated from the left ventricle were electrically stimulated at 0.5 Hz and evoked cytosolic [Ca2+] and contractile responses (sarcomere length shortening) were measured. In initial experiments, the effects of varying concentrations of epinephrine on evoked cytosolic [Ca2+] and contractile responses at 37 °C were measured. In a second series of experiments, cardiomyocytes were cooled from 37 °C to 15 °C, maintained at 15 °C for 2 h, then rewarmed to 37 °C (H/R protocol). Immediately after rewarming, the effects of epinephrine treatment on evoked cytosolic [Ca2+] and contractile responses of cardiomyocytes were determined. At 37 °C, epinephrine treatment increased both cytosolic [Ca2+] and contractile responses of cardiomyocytes in a concentration-dependent manner peaking at 25-50 nM. The evoked contractile response of cardiomyocytes after H/R was reduced while the cytosolic [Ca2+] response was slightly elevated. The diminished contractile response of cardiomyocytes after H/R was not mitigated by epinephrine (25 nM) and epinephrine treatment reduced the exponential time decay constant (Tau), but did not increase the cytosolic [Ca2+] response. We conclude that epinephrine treatment does not mitigate H/R-induced contractile dysfunction in cardiomyocytes.

Effects of rewarming therapies on outcomes in accidental hypothermia: A secondary analysis of a multicenter prospective study.

BACKGROUND: Rewarming therapies for accidental hypothermia (AH) include extracorporeal membrane oxygenation (ECMO) and non-ECMO related (conventional) therapies. However, there are limited data available to inform the selection of conventional rewarming therapy. The aim of the present study was to explore what patients' factors and which rewarming therapy predicted favorable prognosis. METHODS: This study is a secondary analysis of the Intensive Care with Extra Corporeal membrane oxygenation Rewarming in Accidentally Severe Hypothermia (ICE-CRASH) study, a multicenter prospective, observational study conducted in Japan. Enrolled in the ICE-CRASH study were patients aged ≥18 years with a core temperature of ≤32 °C who were transported to the emergency departments of 36 tertiary care hospitals in Japan between 1 December 2019 and 31 March 2022, among whom those who were rewarmed with conventional rewarming therapy were included in the present study. Logistic regression analysis was performed with 28-day survival as the objective variable; and seven factors including age, activities of daily living (ADL) independence, sequential organ failure assessment (SOFA) score, and each rewarming technique as explanatory variables. We performed linear regression analysis to identify whether each rewarming technique was associated with rewarming rate. RESULTS: Of the 499 patients enrolled in the ICE-CRASH study, 371 were eligible for this secondary analysis. The median age was 81 years, 50.9% were male, and the median initial body temperature was 28.8 °C. Age (odds ratio [OR]: 0.97, 95% confidence interval [CI]: 0.94-1.00) and SOFA score (OR: 0.73, 95% CI: 0.67-0.81) were associated with lower survival, whereas ADL independence (OR: 2.31, 95% CI: 1.15-4.63) was associated with higher survival. No conventional rewarming therapy was associated with 28-day survival. Hot bath was associated with a high rewarming rate (regression coefficient: 1.14, 95% CI: 0.75-1.53). CONCLUSION: No conventional rewarming therapy was associated with improved 28-day survival, which suggests that background factors such as age, ADL, and severity of condition contribute more to prognosis than does the selection of rewarming technique.

Predictors of cardiac arrest in severe accidental hypothermia.

STUDY OBJECTIVE: To indicate predictors of witnessed hypothermic cardiac arrest. METHODS: We conducted a retrospective analysis of 182 patients with severe accidental hypothermia (i.e., with core body temperature of ≤28 °C) who presented with preserved spontaneous circulation at first contact with medical services. We divided the study population into two groups: patients who suffered hypothermic cardiac arrest (HCA) at any time between encounter with medical service and restoration of normothermia, and those who did not sustain HCA. The analyzed outcome was the occurrence of cardiac arrest prior to achieving normothermia. Hemodynamic and biochemical parameters were analyzed with regard to their association with the outcome. RESULTS: Fifty-two (29%) patients suffered HCA. In a univariable analysis, four variables were significantly associated with the outcome, namely heart rate (p < 0.001), systolic blood pressure (p = 0.03), ventricular arrhythmia (p = 0.001), and arterial oxygen partial pressure (p = 0.002). In the multivariable logistic regression the best model predicting HCA included heart rate, PaO2, and Base Excess (AUROC = 0.78). In prehospital settings, when blood gas analysis is not available, other multivariable model including heart rate and occurrence of ventricular arrhythmia (AUROC = 0.74) can be used. In this study population, threshold values of heart rate of 43/min, temperature-corrected PaO2 of 72 mmHg, and uncorrected PaO2 of 109 mmHg, presented satisfactory sensitivity and specificity for HCA prediction. CONCLUSIONS: In patients with severe accidental hypothermia, the occurrence of HCA is associated with a lower heart rate, hypoxemia, ventricular arrhythmia, lower BE, and lower blood pressure. These parameters can be helpful in the early selection of high-risk patients and their allocation to extracorporeal rewarming facilities.

Thermal insulation does not hamper assessment of injuries in trauma CT scans.

PURPOSE: The use of thermal insulations reduces the risk of hypothermia, therefore decreases the risk of death in trauma victims. The aim of the study was to assess whether thermal insulations cause artifacts, which may hinder the diagnosis of injuries, and how the used thermo-systems alter the radiation dose in polytrauma computed tomography. METHODS: Computed tomography scans were made using the road accident victim body wrapped consecutively with 7 different covers. 14 injury areas were listed and evaluated by 22 radiologists. The radiation dose was measured using a dosimeter placed on the victim in the abdominal area. RESULTS: No significant artifacts in any of the tested covers were observed. The presence of few minor artifacts did not hinder the assessment of injuries. Certain materials increased (up to 19,1%) and some decreased (up to -30,3%) the absorbed radiation dose. CONCLUSIONS: Thermal insulation systems tested in this study do not cause significant artifacts hindering assessment of injuries in CT scans. Concern for artifacts and increased radiation dose should not be a reason to remove patients' thermal insulation during performing trauma CT-scanning.

Changes in temperature in preheated crystalloids at ambient temperatures relevant to a prehospital setting: an experimental simulation study with the application of prehospital treatment of trauma patients suffering from accidental hypothermia.

BACKGROUND: Accidental hypothermia is common in all trauma patients and contributes to the lethal diamond, increasing both morbidity and mortality. In hypotensive shock, fluid resuscitation is recommended using fluids with a temperature of 37-42°, as fluid temperature can decrease the patient's body temperature. In Sweden, virtually all prehospital services use preheated fluids. The aim of the present study was to investigate how the temperature of preheated infusion fluids is affected by the ambient temperatures and flow rates relevant for prehospital emergency care. METHODS: In this experimental simulation study, temperature changes in crystalloids preheated to 39 °C were evaluated. The fluid temperature changes were measured both in the infusion bag and at the patient end of the infusion system. Measurements were conducted in conditions relevant to prehospital emergency care, with ambient temperatures varying between - 4 and 28 °C and flow rates of 1000 ml/h and 6000 ml/h, through an uninsulated infusion set at a length of 175 cm. RESULTS: The flow rate and ambient temperature affected the temperature in the infusion fluid both in the infusion bag and at the patient end of the system. A lower ambient temperature and lower flow rate were both associated with a greater temperature loss in the infusion fluid. CONCLUSION: This study shows that both a high infusion rate and a high ambient temperature are needed if an infusion fluid preheated to 39 °C is to remain above 37 °C when it reaches the patient using a 175-cm-long uninsulated infusion set. It is apparent that the lower the ambient temperature, the higher the flow rate needs to be to limit temperature loss of the fluid.

Effect of wet clothing removal on skin temperature in subjects exposed to cold and wrapped in a vapor barrier: a human, randomized, crossover field study.

BACKGROUND: Prehospital care for cold-stressed and hypothermic patients focuses on effective insulation and rewarming. When encountering patients wearing wet clothing, rescuers can either remove the wet clothing before isolating the patient or isolate the patient using a vapor barrier. Wet clothing removal increases skin exposure but avoids the need to heat the wet clothing during rewarming. Leaving wet clothing on will avoid skin exposure but is likely to increase heat loss during rewarming. This study aimed to evaluate the effect of wet clothing removal compared to containing the moisture using a vapor barrier on skin temperature in a prehospital setting. METHODS: This randomized crossover experimental field study was conducted in a snow cave in Hemsedal, Norway. After an initial cooling phase of 30 min while wearing wet clothes, the participants were subjected to one of two rewarming scenarios: (1) wet clothing removal and wrapping in a vapor barrier, insulating blankets, and windproof outer shell (dry group) or (2) wrapping in a vapor barrier, insulating blankets, and windproof outer shell (wet group). The mean skin temperature was the primary outcome whereas subjective scores for both thermal comfort and degree of shivering were secondary outcomes. Primary outcome data were analyzed using the analysis of covariance (ANCOVA). RESULTS: After an initial decrease in temperature during the exposure phase, the dry group had a higher mean skin temperature compared to the wet group after only 2 min. The skin-rewarming rate was highest in the initial rewarming stages for both groups, but increased in the dry group as compared to the wet group in the first 10 min. Return to baseline temperature occurred significantly faster in the dry group (mean 12.5 min [dry] vs. 28.1 min [wet]). No intergroup differences in the subjective thermal comfort or shivering were observed. CONCLUSION: Removal of wet clothing in combination with a vapor barrier increases skin rewarming rate compared to encasing the wet clothing in a vapor barrier, in mild cold and environments without wind. TRIAL REGISTRATION: ClinicalTrials.gov ID NCT05996757, retrospectively registered 18/08/2023.

Impact of Prewarming on Maintaining Perioperative Body Temperature: A Randomized Clinical Trial.

PURPOSE: To determine the prewarming effect on body temperature in the perioperative period of patients undergoing conventional abdominal surgery and the level of thermal comfort. DESIGN: A randomized controlled clinical trial. METHODS: A Brazilian oncology hospital located in São Paulo. A total of 99 patients aged 18 years or over undergoing elective conventional abdominal surgeries, with a minimum duration of 1 hour of anesthesia. The study was carried out from 2019 to 2021. Patients were randomized into 3 groups: prewarming with a blanket and cotton sheet (control; n = 33); prewarming with a forced-air warming system for 20 minutes (intervention 1; n = 33); prewarming with a forced-air warming system for 30 minutes (intervention 2; n = 33). Central temperature was measured by a zero-heat-flux temperature sensor every 20 minutes from the preoperative period until the surgery end time. The level of thermal comfort was determined through self-report during the preanesthetic and postanesthetic periods. FINDINGS: There was a significant difference between the temperatures between the groups (P = .048), with evidence of greater benefit in maintaining the temperature in the group that received the prewarming intervention for 20 minutes. There was no significant difference between the percentage of temperatures below 36 °C among the groups (P = .135). Patients in the intervention groups were more comfortable during the postanesthetic recovery period than those in the control group (P = .048). Only 7 (8.24%) patients had postoperative chills (P = .399) and more than half of these incidents occurred in the control group (4; 13.3%). CONCLUSIONS: Prewarming for 20 minutes obtained the best results, showing the lowest average of temperature episodes below 36 °C during the intraoperative period and greater thermal comfort as reported by patients.

[Diagnostic criteria of death cause from low temperature in air and water established by traditional expert examination methods]. / Diagnosticheskie kriterii prichiny smerti ot deistviya nizkoi temperatury na vozdukhe i v vode, ustanavlivaemye s pomoshch'yu traditsionnykh metodov ekspertnogo issledovaniya.

Death from general hypothermia is one of the leading causes in the structure of violent death in the Russian Federation. OBJECTIVE: To clarify and supplement the complex of differential diagnostic macro- and microscopic signs of a fatal acute general cold trauma received when person is in the air and water. MATERIAL AND METHODS: The conclusions of forensic medical experts on the bodies of people who died from hypothermia in the air and in water (by 150 observations) were analyzed. Methods of descriptive statistics, calculation of the frequency ratio of signs' occurrence were used. RESULTS: The article provides quantitative assessment of occurrence (detection) rate of diagnostically significant signs established with the help of traditional methods of expert examination. A new classification of diagnostic death signs from hypothermia taking into account their differential diagnostic significance and reflecting the conditions of a person's stay in the air and water in the pre-mortem and post-mortem periods, as well as terminal period mechanisms is proposed. CONCLUSION: The established complexes of signs provide an objective basis for determining death cause in non-obvious conditions when cold exposure is expected to be one of the most damaging factors.

E-CPR in Cardiac Arrest due to Accidental Hypothermia Using Intensivist Cannulators: A Case Series of Nine Consecutive Patients.

Background: Severe accidental hypothermia (AH) accounts for over 1300 deaths/year in the United States. Early extracorporeal life support (ECLS) is recommended for hypothermic cardiac arrest. We describe the use of a rapid-deployment extracorporeal cardiopulmonary resuscitation (E-CPR) team using intensivist physicians (IPs) as cannulators and report the outcomes of consecutive patients cannulated for ECLS to manage cardiac arrest due to AH. Methods: We reviewed all patients managed with veno-arterial (V-A) ECLS for hypothermic cardiac arrest between January 1, 2017 and November 1, 2021. For each patient- age, sex, cause of hypothermia, initial core temperature, initial rhythm, time from arrest to cannulation, cannula configuration, pH, lactate, potassium, cannulation complications, duration of ECLS, hospital length of stay, mortality, and cerebral performance category (CPC) at discharge were reviewed. Results: Nine consecutive patients were identified that underwent V-A ECLS for cardiac arrest due to AH. Seven (78%) were witnessed arrests. Initial rhythm was ventricular fibrillation (VF) in eight patients and pulseless electrical activity (PEA) in one. The mean initial core temperature was 23.8 degrees Celsius. The mean time from arrest to cannulation was 58 min (range 17 to 251 min). There were no complications related to cannulation. The mean duration of ECLS was 39.1 h. All nine patients were discharged alive with a Cerebral Performance score of one or two. Conclusion: In this case series of consecutive patients reporting intensivist-deployed E-CPR for cardiac arrest due to AH, all patients survived to discharge with a favorable neurologic outcome. A rapidly available E-CPR team utilizing intensivist cannulators may improve outcomes in patients with cardiac arrest due to AH.

Rewarming from unwitnessed hypothermic cardiac arrest with good neurological recovery using extracorporeal membrane oxygenation.

A 26-year-old man, who was training in bad weather for a mountain ultramarathon, became hypothermic after running for 4 h. He deteriorated and was unable to continue. His running partner went for help. The man suffered an unwitnessed hypothermic cardiac arrest. The on-site management and evacuation are described and included the use of intermittent cardiopulmonary resuscitation and a mechanical device during transport. The patient was successfully resuscitated and rewarmed by Extracorporeal Membrane Oxygenation (ECMO) after more than 2 h of cardiopulmonary resuscitation. After 14 h of ECMO support and five days of ventilation, the patient subsequently made a good neurological recovery. At hospital discharge, he had normal cerebral function, and an improving peripheral polyneuropathy affecting distal limbs, with paraesthesia in both feet and reduced coordination and fine motor skills in both hands.

What is the best way to keep the patient warm during technical rescue? Results from two prospective randomised controlled studies with healthy volunteers.

BACKGROUND: Accidental hypothermia is a manifest problem during the rescue of entrapped victims and results in different subsequent problems as coagulopathy and wound infection. Different warming methods are available for the preclinicial use. However, their effectiveness has hardly been evaluated. METHODS: In a first step a survey among German fire brigades was performed with questions about the most used warming methods. In a second step two crossover studies were conducted. In each study two different warming method were compared with forced air warming - which is the most frequently used and highly effective warming method in operation rooms (Study A: halogen floodlight vs. forced air warming; Study B: forced air warming vs. fleece blanket). In both studies healthy volunteers (Study A: 30 volunteers, Study B: 32 volunteers) were sitting 60 min in a cold store. In the first 21 min there was no subject warming. Afterwards the different warming methods were initiated. Every 3 min parameters like skin temperature, core body temperature and cold perception on a 10-point numeric rating scale were recorded. Linear mixed models were fitted for each parameter to check for differences in temperature trajectories and cold perception with regard to the different warming methods. RESULTS: One hundred fifty-one German fire brigades responded to the survey. The most frequently used warming methods were different rescue blankets (gold/silver, wool) and work light (halogen floodlights). Both studies (A and B) showed significantly (p < 0.05) higher values in mean skin temperature, mean body temperature and total body heat for the forced air warming methods compared to halogen floodlight respectively fleece blanket shortly after warming initiation. In contrast, values for the cold perception were significantly lower (less unpleasant cold perception) during the phase the forced air warming methods were used, compared to the fleece blanket or the halogen floodlight was used. CONCLUSION: Forced air warming methods used under the standardised experimental setting are an effective method to keep patients warm during technical rescue. Halogen floodlight has an insufficient effect on the patient's heat preservation. In healthy subjects, fleece blankets will stop heat loss but will not correct heat that has already been lost. TRIAL REGISTRATION: The studies were registered retrospectively on 14/02/2022 on the German Clinical Trials registry (DRKS) with the number DRKS00028079.

Resuscitation from severe accidental hypothermia by active core rewarming via an indwelling peritoneal dialysis catheter.

Accidental hypothermia is a life-threatening medical condition, which requires the appropriate rewarming strategy with careful monitoring. Active core rewarming is often necessary in the management of severe hypothermia. However, especially in the emergent clinical setting, immediate establishment of a reliable route for active core rewarming is difficult. Severe accidental hypothermia in patients dependent on peritoneal dialysis or combination of hemodialysis with peritoneal dialysis is extremely rare, and the ideal rewarming procedure for these patients is unclear. To our knowledge, this is the first case report illustrating the application of an indwelling peritoneal dialysis catheter to active core rewarming in the management of severe accidental hypothermia. A 64-year-old female with type 1 diabetes and end-stage renal disease (ESRD) on combination of hemodialysis with peritoneal dialysis was delivered to our hospital due to severe accidental hypothermia. On presentation, she was unresponsive and her core temperature was 22.8 °C. Since rewarming by an electric blanket and warmed saline infusion was ineffective, infusion of warmed peritoneal dialysis solution via an indwelling peritoneal dialysis catheter was performed in the emergency room. In the next few hours, her body temperature recovered to normal level, and she regained consciousness. During resuscitation, complications related to rewarming, such as arrhythmia or hypotension, were not observed. She was discharged without any sequelae. Indwelling peritoneal dialysis catheters, if available, could be utilized as the safe and reliable route for active core rewarming in ESRD patients.

Thermal suit connected to a forced-air warming unit for preventing intraoperative hypothermia: A randomised controlled trial.

BACKGROUND: Inadvertent intraoperative hypothermia is a common occurrence in surgical patients. A thermal suit is an option for passive insulation. However, active warming is known to be more effective. Therefore, we hypothesised that a forced-air warming (FAW) unit connected to the thermal suit is superior to a commercial FAW blanket and a warming mattress in breast cancer surgery. METHODS: Forty patients were randomised to this prospective, clinical trial to wear either the thermal suit or conventional hospital clothes under general anaesthesia. The Thermal suit group had a FAW unit set to 38°C and connected to the legs of the suit. The Hospital clothes group had a lower body blanket set to 38°C and a warming mattress set to 37°C. Core temperature was measured with zero-heat-flux sensor. The primary outcome was core temperature on admission to the recovery room. RESULTS: There was no difference in mean core temperatures at anaesthetic induction (P = .4) or on admission to the recovery room (P = .07). One patient in the Thermal suit group (5%) vs six patients in the Hospital clothes group (32%) suffered from intraoperative hypothermia (P = .04, 95% CI 1.9%-49%). Mean skin temperatures (MSTs) were higher in the Thermal suit group during anaesthesia. No burns or skin irritations were reported. Two patients in the Thermal suit group sweated. CONCLUSIONS: A thermal suit connected to a FAW unit was not superior to a commercial FAW blanket, although the incidence of intraoperative hypothermia was lower in patients treated with a thermal suit.

Outcomes of patients suffering unwitnessed hypothermic cardiac arrest rewarmed with extracorporeal life support: A systematic review.

Prolonged cardiac arrest (CA) may lead to neurologic deficit in survivors. Good outcome is especially rare when CA was unwitnessed. However, accidental hypothermia is a very specific cause of CA. Our goal was to describe the outcomes of patients who suffered from unwitnessed hypothermic cardiac arrest (UHCA) supported with Extracorporeal Life Support (ECLS). We included consecutive patients' cohorts identified by systematic literature review concerning patients suffering from UHCA and rewarmed with ECLS. Patients were divided into four subgroups regarding the mechanism of cooling, namely: air exposure; immersion; submersion; and avalanche. A statistical analysis was performed in order to identify the clinical parameters associated with good outcome (survival and absence of neurologic impairment). A total of 221 patients were included into the study. The overall survival rate was 27%. Most of the survivors (83%), had no neurologic deficit. Asystole was the presenting CA rhythm in 48% survivors, of which 79% survived with good neurologic outcome. Variables associated with survival included the following: female gender (P < .001); low core temperature (P = .005); non-asphyxia-related mechanism of cooling (P < .001); pulseless electrical activity as an initial rhythm (P < .001); high blood pH (P < .001); low lactate levels (P = .003); low serum potassium concentration (P < .001); and short resuscitation duration (P = .004). Severely hypothermic patients with unwitnessed CA may survive with good neurologic outcome, including those presenting as asystole. The initial blood pH, potassium, and lactate concentration may help predict outcome in hypothermic CA.

Resistance to ventricular fibrillation predicted by the QRS/QTc - Ratio in an intact rat model of hypothermia/rewarming.

Accidental hypothermia is associated with increased risk for arrhythmias. QRS/QTc is proposed as an ECG-marker, where decreasing values predict hypothermia-induced ventricular arrhythmias. If reliable it should also predict nonappearance of arrhythmias, observed in species like rat that regularly tolerate prolonged hypothermia. A rat model designed for studying cardiovascular function during cooling, hypothermia and subsequent rewarming was chosen due to species-dependent resistance to ventricular arrhythmias. ECG was recorded throughout the protocol. No ventricular arrhythmias occurred during experiments. QRS/QTc increased throughout the cooling period and remained above normothermic baseline until rewarmed. Different from the high incidence of hypothermia-induced ventricular arrhythmias in accidental hypothermia patients, where QRS/QTc ratio is decreased in moderate hypothermia; hypothermia and rewarming of rats is not associated with increased risk for ventricular fibrillation. This resistance to lethal hypothermia-induced arrhythmias was predicted by QRS/QTc.

Association between frailty and mortality among patients with accidental hypothermia: a nationwide observational study in Japan.

BACKGROUND: Frailty has been associated with a risk of adverse outcomes, and mortality in patients with various conditions. However, there have been few studies on whether or not frailty is associated with mortality in patients with accidental hypothermia (AH). In this study, we aim to determine this association in patients with AH using Japan's nationwide registry data. METHODS: The data from the Hypothermia STUDY 2018&19, which included patients of ≥18 years of age with a body temperature of ≤35 °C, were obtained from a multicenter registry for AH conducted at 120 institutions throughout Japan, collected from December 2018 to February 2019 and December 2019 to February 2020. The clinical frailty scale (CFS) score was used to determine the presence and degree of frailty. The primary outcome was the comparison of mortality between the frail and non-frail patient groups. RESULTS: In total, 1363 patients were included in the study, of which 920 were eligible for the analysis. The 920 patients were divided into the frail patient group (N = 221) and non-frail patient group (N = 699). After 30-days of hospitalization, 32.6% of frail patients and 20.6% of non-frail patients had died (p < 0.001). Frail patients had a significantly higher risk of 90-day mortality (Hazard ratio [HR], 1.64; 95% confidence interval [CI], 1.25-2.17; p < 0.001). Based on the Cox proportional hazards analysis using multiple imputation, after adjustment for age, potassium level, lactate level, pH value, sex, CPK level, heart rate, platelet count, location of hypothermia incidence, and rate of tracheal intubation, the HR was 1.69 (95% CI, 1.25-2.29; p < 0.001). CONCLUSIONS: This study showed that frailty was associated with mortality in patients with AH. Preventive interventions for frailty may help to avoid death caused by AH.

Accidental hypothermia: Factors related to a prolonged hospital stay - A nationwide observational study in Japan.

BACKGROUND: The incidence of accidental hypothermia (AH) is low, and the length of hospital stay in patients with AH remains poorly understood. The present study explored which factors were related to prolonged hospitalization among patients with AH using Japan's nationwide registry data. METHODS: The data from the Hypothermia STUDY 2018, which included patients ≥18 years old with a body temperature ≤ 35 °C, were obtained from a multicenter registry for AH conducted at 89 institutions throughout Japan, collected from December 1, 2018, to February 28, 2019. The patients were divided into a "short-stay patients" group (within 7 days) and "long-stay patients" group (more than 7 days). A logistic regression analysis after multiple imputation was performed to obtain odds ratios (ORs) for prolonged hospitalization with age, frailty, location, causes underlying the hypothermia, temperature, pH, potassium level, and disseminated intravascular coagulation (DIC) score as independent variables. RESULTS: In total, 656 patients were included in the study, of which 362 were eligible for the analysis. The median length of hospital stay was 17 days. Of the 362 patients, 265 (73.2%) stayed in the hospital for more than 7 days. The factors associated with prolonged hospitalization were frailty (OR, 2.11; 95% confidence interval [CI], 1.09-4.10; p = 0.027), the occurrence of indoor (OR, 3.20; 95% CI, 1.58-6.46; p = 0.001), alcohol intoxication (OR, 0.17; 95% CI, 0.05-0.56; p = 0.004), pH (OR, 0.07; 95% CI, 0.01-0.76; p = 0.029), potassium level (OR, 1.36; 95% CI, 1.00-1.85; p = 0.048), and DIC score (OR, 1.54; 95% CI, 1.13-2.10; p = 0.006). CONCLUSIONS: Frailty, indoor situation, alcohol intoxication, pH value, potassium level, and DIC score were factors contributing to prolonged hospitalization in patients with AH. Preventing frailty may help reduce the length of hospital stay in patients with AH. In addition, measuring the pH value and potassium level by an arterial blood gas analysis at the ED is recommended for the early evaluation of AH.

Successful Non-Extracorporeal Rewarming from Hypothermic Cardiac Arrest: 2 Cases.

Accidental hypothermia (core temperature <35°C) is a complication in persons who have fallen into crevasses; hypothermic cardiac arrest is the most serious complication. Extracorporeal life support (ECLS) is the optimal method for rewarming hypothermic cardiac arrest patients, but it may not be readily available and non-ECLS rewarming may be required. We report the medical course of 2 patients with hypothermic cardiac arrest, each of whom had fallen into a crevasse. They were treated successfully with non-ECLS rewarming using peritoneal and thoracic lavage. We discuss non-ECLS treatment options for hypothermic cardiac arrest and describe successful non-ECLS rewarming in an outlying hospital without ECLS rewarming capability in the Grossglockner region of Austria in 1990 and 2003. Both patients survived neurologically intact. Non-ECLS rewarming in a trauma center without ECLS capabilities is feasible and can result in a good outcome when ECLS is not available. The best non-ECLS rewarming method for hypothermic cardiac arrest patients has not yet been established. Non-ECLS rewarming should be adapted to local capabilities. To obtain more robust evidence, it seems reasonable to pool data on the treatment and outcome of non-ECLS rewarming in hypothermic cardiac arrest patients.

A Guideline-Based Policy to Decrease Intensive Care Unit Admission Rates for Accidental Hypothermia.

RATIONALE: Despite guidelines advising passive rewarming for mild accidental hypothermia (AH), patients are frequently admitted to intensive care unit (ICU) for active rewarming using a forced-air warming device. We implemented a new policy at our institution aimed at safely reducing ICU admissions for AH. We analyzed our practice pre- and post-policy intervention and compared our experiences with acute care hospitals in Connecticut. METHODS: A retrospective chart review was performed on 203 participants with AH identified by primary and secondary discharge codes. Our new policy recommended passive rewarming on the medical floors for mild hypothermia (>32°C) and ICU admission for moderate hypothermia (<32°C). Practices of other Connecticut hospitals were obtained by surveying ICU nurse managers and medical directors. RESULTS: Over a 3-year period, prior to rewarming policy change, 64% (n = 92) of patients with AH were admitted to ICU, with a mean ICU length of stay (LOS [SD]) of 2.75 (2.2) days. After the policy change, over a 3-year period, 15% (n = 9) were admitted to ICU (P < .001), with an ICU LOS of 2.11 (0.9) days (P = 0.005). In both groups with AH, altered mental status, infection, and acute alcohol intoxication were the most common diagnoses at presentation. Alcohol intoxication was more prevalent in the post-policy intervention group, pre 17% versus post 46% (P < .001). No complications such as dermal burns or cardiac arrhythmias were noted with forced-air warming device use during either time period. Among the 29 hospitals surveyed, 20 used active rewarming in ICU or intermediate care units and 9 cared for patients on telemetry units. Most hospitals used active external rewarming for core body temperature of <35°C; however, 37% of hospitals performed active rewarming at temperatures >35°Cor lacked a policy. CONCLUSIONS: Reserving forced-air warming devices for the treatment of moderate-to-severe hypothermia (<32°C) significantly reduced ICU admissions for AH.

Extracorporeal rewarming from experimental hypothermia: Effects of hydroxyethyl starch versus saline priming on fluid balance and blood flow distribution.

NEW FINDINGS: What is the central question of this study? Mortality in accidental hypothermia patients rewarmed by extracorporeal circulation remains high. Knowledge concerning optimal fluid additions for extracorporeal rewarming is lacking, with no apparent consensus. Does colloid versus crystalloid priming have different effects on fluid balance and blood flow distribution during extracorporeal rewarming? What is the main finding and its importance? In our rat model of extracorporeal rewarming from hypothermic cardiac arrest, hydroxyethyl starch generates less tissue oedema and increases circulating blood volume and organ blood flow, compared with saline. The composition of fluid additions appears to be important during extracorporeal rewarming from hypothermia. ABSTRACT: Rewarming by extracorporeal circulation (ECC) is the recommended treatment for accidental hypothermia patients with cardiac instability. Hypothermia, along with initiation of ECC, introduces major changes in fluid homeostasis and blood flow. Scientific data to recommend best practice use of ECC for rewarming these patients is lacking, and no current guidelines exist concerning the choice of priming fluid for the extracorporeal circuit. The primary aim of this study was to compare the effects of different fluid protocols on fluid balance and blood flow distribution during rewarming from deep hypothermic cardiac arrest. Sixteen anaesthetized rats were cooled to deep hypothermic cardiac arrest and rewarmed by ECC. During cooling, rats were equally randomized into two groups: an extracorporeal circuit primed with saline or primed with hydroxyethyl starch (HES). Calculations of plasma volume (PV), circulating blood volume (CBV), organ blood flow, total tissue water content, global O2 delivery and consumption were made. During and after rewarming, the pump flow rate, mean arterial pressure, PV and CBV were significantly higher in HES-treated compared with saline-treated rats. After rewarming, the HES group had significantly increased global O2 delivery and blood flow to the brain and kidneys compared with the saline group. Rats in the saline group demonstrated a significantly higher total tissue water content in the kidneys, skeletal muscle and lung. Compared with crystalloid priming, the use of an iso-oncotic colloid prime generates less tissue oedema and increases PV, CBV and organ blood flow during ECC rewarming. The composition of fluid additions appears to be an important factor during ECC rewarming from hypothermia.