Accidental hypothermia

Maintaining intravenous volume mitigates hypothermia-induced myocardial dysfunction and accumulation of intracellular Ca2

NEW FINDINGS

What is the central question of this study? Detailed guidelines for volume replacement to counteract hypothermia-induced intravascular fluid loss are lacking. Evidence suggests colloids might have beneficial effects compared to crystalloids. Are central haemodynamic function and level of hypothermia-induced calcium overload, as a marker of cardiac injury, restored by fluid substitution during rewarming, and are colloids favourable to crystalloids? What is the main finding and its importance? Infusion with crystalloid or dextran during rewarming abolished post-hypothermic cardiac dysfunction, and partially mitigated myocardial calcium overload. The effects of volume replacement to support haemodynamic function are comparable to those using potent cardio-active drugs. These findings underline the importance of applying intravascular volume replacement to maintain euvolaemia during rewarming.

ABSTRACT

Previous research exploring pathophysiological mechanisms underlying circulatory collapse after rewarming victims of severe accidental hypothermia has documented post-hypothermic cardiac dysfunction and hypothermia-induced elevation of intracellular Ca²⁺ concentration ([Ca²⁺ ]_i ) in myocardial cells. The aim of the present study was to examine if maintaining euvolaemia during rewarming mitigates cardiac dysfunction and/or normalizes elevated myocardial [Ca²⁺ ]_i . A total of 21 male Wistar rats (300 g) were surface cooled to 15°C, then maintained at 15°C for 4 h, and subsequently rewarmed to 37°C. The rats were randomly assigned to one of three groups: (1) non-intervention control (n = 7), (2) dextran treated (i.v. 12 ml/kg dextran 70; n = 7), or (3) crystalloid treated (24 ml/kg 0.9% i.v. saline; n = 7). Infusions occurred during the first 30 min of rewarming. Arterial blood pressure, stroke volume (SV), cardiac output (CO), contractility (dP/dt_max ) and blood gas changes were measured. Post-hypothermic changes in [Ca²⁺ ]_i were measured using the method of radiolabelled Ca²⁺ (⁴⁵ Ca²⁺ ). Untreated controls displayed post-hypothermic cardiac dysfunction with significantly reduced CO, SV and dP/dt_max . In contrast, rats receiving crystalloid or dextran treatment showed a return to pre-hypothermic control levels of CO and SV after rewarming, with the dextran group displaying significantly better amelioration of post-hypothermic cardiac dysfunction than the crystalloid group. Compared to the post-hypothermic increase in myocardial [Ca²⁺ ]_i in non-treated controls, [Ca²⁺ ]_i values with crystalloid and dextran did not increase to the same extent after rewarming. Volume replacement with crystalloid or dextran during rewarming abolishes post-hypothermic cardiac dysfunction, and partially mitigates the hypothermia-induced elevation of [Ca²⁺ ]_i .

Na+/Ca2+ exchanger mediates cold Ca2+ signaling conserved for temperature-compensated circadian rhythms

Circadian rhythms are based on biochemical oscillations generated by clock genes/proteins, which independently evolved in animals, fungi, plants, and cyanobacteria. Temperature compensation of the oscillation speed is a common feature of the circadian clocks, but the evolutionary-conserved mechanism has been unclear. Here, we show that Na⁺/Ca²⁺ exchanger (NCX) mediates cold-responsive Ca²⁺ signaling important for the temperature-compensated oscillation in mammalian cells. In response to temperature decrease, NCX elevates intracellular Ca²⁺, which activates Ca²⁺/calmodulin-dependent protein kinase II and accelerates transcriptional oscillations of clock genes. The cold-responsive Ca²⁺ signaling is conserved among mice, Drosophila, and Arabidopsis The mammalian cellular rhythms and Drosophila behavioral rhythms were severely attenuated by NCX inhibition, indicating essential roles of NCX in both temperature compensation and autonomous oscillation. NCX also contributes to the temperature-compensated transcriptional rhythms in cyanobacterial clock. Our results suggest that NCX-mediated Ca²⁺ signaling is a common mechanism underlying temperature-compensated circadian rhythms both in eukaryotes and prokaryotes.

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.

European Resuscitation Council Guidelines 2021: Cardiac arrest in special circumstances

These European Resuscitation Council (ERC) Cardiac Arrest in Special Circumstances guidelines are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. This section provides guidelines on the modifications required to basic and advanced life support for the prevention and treatment of cardiac arrest in special circumstances; specifically special causes (hypoxia, trauma, anaphylaxis, sepsis, hypo/hyperkalaemia and other electrolyte disorders, hypothermia, avalanche, hyperthermia and malignant hyperthermia, pulmonary embolism, coronary thrombosis, cardiac tamponade, tension pneumothorax, toxic agents), special settings (operating room, cardiac surgery, catheter laboratory, dialysis unit, dental clinics, transportation (in-flight, cruise ships), sport, drowning, mass casualty incidents), and special patient groups (asthma and COPD, neurological disease, obesity, pregnancy).

Veno-Venous Extracorporeal Rewarming Using Dual-Lumen Cannula in Accidental Hypothermia

Accidental hypothermia with a core temperature below 28°C is associated with an increased risk of hemodynamic instability. It is difficult to predict which patients will survive with a favorable neurologic outcome; therefore, decision-making regarding extracorporeal support is not straightforward. We report a case of rewarming using veno-venous dual-lumen cannula as an alternative to veno-arterial support with full recovery and normal neurologic examination. In centers where extracorporeal membrane oxygenation is available, rewarming using veno-venous dual-lumen extracorporeal support may be a useful strategy to mitigate the risks associated with veno-arterial extracorporeal support.

Clinical staging of accidental hypothermia: The Revised Swiss System: Recommendation of the International Commission for Mountain Emergency Medicine (ICAR MedCom)

Clinical staging of accidental hypothermia is used to guide out-of-hospital treatment and transport decisions. Most clinical systems utilize core temperature, by measurement or estimation, to stage hypothermia, despite the challenge of obtaining accurate field measurements. Recent studies have demonstrated that field estimation of core temperature is imprecise. We propose a revision of the original Swiss Staging system. The revised system uses the risk of cardiac arrest, instead of core temperature, to determine the staging level. Our revised system simplifies assessment by using the level of responsiveness, based on the AVPU scale, and by removing shivering as a stage-defining sign.

Expert consensus on the prevention, diagnosis and treatment of cold injury in China, 2020

Cold injury refers to local or systemic injury caused by a rapid, massive loss of body heat in a cold environment. The incidence of cold injury is high. However, the current situation regarding the diagnosis and treatment of cold injury in our country is not ideal. To standardize and improve the level of clinical diagnosis and treatment of cold injury in China, it is necessary to make a consensus that is practical and adapted to the conditions in China. We used the latest population-level epidemiological and clinical research data, combined with relevant literature from China and foreign countries. The consensus was developed by a joint committee of multidisciplinary experts. This expert consensus addresses the epidemiology, diagnosis, on-site emergency procedures, in-hospital treatment, and prevention of cold injury.

Perinatal Infection: A Major Contributor to Efficacy of Cooling in Newborns Following Birth Asphyxia

Neonatal encephalopathy (NE) is a global burden, as more than 90% of NE occurs in low- and middle-income countries (LMICs). Perinatal infection seems to limit the neuroprotective efficacy of therapeutic hypothermia. Efforts made to use therapeutic hypothermia in LMICs treating NE has led to increased neonatal mortality rates. The heat shock and cold shock protein responses are essential for survival against a wide range of stressors during which organisms raise their core body temperature and temporarily subject themselves to thermal and cold stress in the face of infection. The characteristic increase and decrease in core body temperature activates and utilizes elements of the heat shock and cold shock response pathways to modify cytokine and chemokine gene expression, cellular signaling, and immune cell mobilization to sites of inflammation, infection, and injury. Hypothermia stimulates microglia to secret cold-inducible RNA-binding protein (CIRP), which triggers NF-κB, controlling multiple inflammatory pathways, including nod-like receptor family pyrin domain containing 3 (NLRP3) inflammasomes and cyclooxygenase-2 (COX-2) signaling. Brain responses through changes in heat shock protein and cold shock protein transcription and gene-expression following fever range and hyperthermia may be new promising potential therapeutic targets.

Machine learning-based prediction models for accidental hypothermia patients

Background

Accidental hypothermia is a critical condition with high risks of fatal arrhythmia, multiple organ failure, and mortality; however, there is no established model to predict the mortality. The present study aimed to develop and validate machine learning-based models for predicting in-hospital mortality using easily available data at hospital admission among the patients with accidental hypothermia.

Method

This study was secondary analysis of multi-center retrospective cohort study (J-point registry) including patients with accidental hypothermia. Adult patients with body temperature 35.0 °C or less at emergency department were included. Prediction models for in-hospital mortality using machine learning (lasso, random forest, and gradient boosting tree) were made in development cohort from six hospitals, and the predictive performance were assessed in validation cohort from other six hospitals. As a reference, we compared the SOFA score and 5A score.

Results

We included total 532 patients in the development cohort [N = 288, six hospitals, in-hospital mortality: 22.0% (64/288)], and the validation cohort [N = 244, six hospitals, in-hospital mortality 27.0% (66/244)]. The C-statistics [95% CI] of the models in validation cohorts were as follows: lasso 0.784 [0.717–0.851] , random forest 0.794[0.735–0.853], gradient boosting tree 0.780 [0.714–0.847], SOFA 0.787 [0.722–0.851], and 5A score 0.750[0.681–0.820]. The calibration plot showed that these models were well calibrated to observed in-hospital mortality. Decision curve analysis indicated that these models obtained clinical net-benefit.

Conclusion

This multi-center retrospective cohort study indicated that machine learning-based prediction models could accurately predict in-hospital mortality in validation cohort among the accidental hypothermia patients. These models might be able to support physicians and patient’s decision-making. However, the applicability to clinical settings, and the actual clinical utility is still unclear; thus, further prospective study is warranted to evaluate the clinical usefulness.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40560-021-00525-z.

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020)

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020), a Japanese-specific set of clinical practice guidelines for sepsis and septic shock created as revised from J-SSCG 2016 jointly by the Japanese Society of Intensive Care Medicine and the Japanese Association for Acute Medicine, was first released in September 2020 and published in February 2021. An English-language version of these guidelines was created based on the contents of the original Japanese-language version. The purpose of this guideline is to assist medical staff in making appropriate decisions to improve the prognosis of patients undergoing treatment for sepsis and septic shock. We aimed to provide high-quality guidelines that are easy to use and understand for specialists, general clinicians, and multidisciplinary medical professionals. J-SSCG 2016 took up new subjects that were not present in SSCG 2016 (e.g., ICU-acquired weakness [ICU-AW], post-intensive care syndrome [PICS], and body temperature management). The J-SSCG 2020 covered a total of 22 areas with four additional new areas (patient- and family-centered care, sepsis treatment system, neuro-intensive treatment, and stress ulcers). A total of 118 important clinical issues (clinical questions, CQs) were extracted regardless of the presence or absence of evidence. These CQs also include those that have been given particular focus within Japan. This is a large-scale guideline covering multiple fields; thus, in addition to the 25 committee members, we had the participation and support of a total of 226 members who are professionals (physicians, nurses, physiotherapists, clinical engineers, and pharmacists) and medical workers with a history of sepsis or critical illness. The GRADE method was adopted for making recommendations, and the modified Delphi method was used to determine recommendations by voting from all committee members. As a result, 79 GRADE-based recommendations, 5 Good Practice Statements (GPS), 18 expert consensuses, 27 answers to background questions (BQs), and summaries of definitions and diagnosis of sepsis were created as responses to 118 CQs. We also incorporated visual information for each CQ according to the time course of treatment, and we will also distribute this as an app. The J-SSCG 2020 is expected to be widely used as a useful bedside guideline in the field of sepsis treatment both in Japan and overseas involving multiple disciplines.

Epidemiology, Management, and Outcomes of Accidental Hypothermia: A Multicenter Study of Regional Care

BACKGROUND

Hypothermia is an uncommon, potentially life-threatening condition. We hypothesized (1) advanced rewarming techniques were more frequent with increased hypothermia severity, (2) active rewarming is increasingly performed with smaller intravascular catheters and decreased cardiopulmonary bypass, and (3) mortality was associated with age, hypothermia severity, and type.

METHODS

Trauma patients with temperatures <35°C at 4 ACS-verified trauma centers in Wisconsin and Minnesota from 2006 to 2016 were reviewed. Statistical analysis included chi-square and Fisher's exact tests. A P value < .05 was considered significant.

RESULTS

337 patients met inclusion criteria; primary hypothermia was identified in 127 (38%), secondary in 113 (34%), and mixed primary/secondary in 96 (28%) patients. Hypothermia was mild in 69%, moderate in 26%, and severe in 5% of patients. Intravascular rewarming catheter was the most frequent advanced modality (2%), used increasingly since 2014. Advanced techniques were used for primary (12%) vs. secondary (0%) and mixed (5%) (P = .0002); overall use increased with hypothermia severity but varied by institution. Dysrhythmia, acute kidney injury, and frostbite risk worsened with hypothermia severity (P < .0001, P = .031, and P < .0001, respectively). Mortality was greatest in patients with mixed hypothermia (39%, P = .0002) and age >65 years (33%, P = .03). Thirty-day mortality rates were similar among severe, moderate, and mild hypothermia (P = .44).

CONCLUSION

Advanced rewarming techniques were used more frequently in severe and primary hypothermia but varied among institutions. Advanced rewarming was less common in mixed hypothermia; mortality was highest in this subgroup. Reliance on smaller intravascular catheters for advanced rewarming increased over time. Given inconsistencies in management, implementation of guidelines for hypothermia management appears necessary.

Vital Signs in Accidental Hypothermia

Pasquier, Mathieu, Evelien Cools, Ken Zafren, Pierre-Nicolas Carron, Vincent Frochaux, and Valentin Rousson. Vital signs in accidental hypothermia. High Alt Med Biol. 22: 142-147, 2021. Background: Clinical indicators are used to stage hypothermia and to guide management of hypothermic patients. We sought to better characterize the influence of hypothermia on vital signs, including level of consciousness, by studying cases of patients suffering from accidental hypothermia. Materials and Methods: We retrospectively included patients aged ≥18 years admitted to the hospital with a core temperature below 35°C. We identified the cases from a literature review and from a retrospective case series of hypothermic patients admitted to the hospital between 1994 and 2016. Patients who experienced cardiac arrest, as well as those with potential confounders such as concomitant diseases or intoxications, were excluded. Relationships between core temperature and heart rate, systolic blood pressure, respiratory rate, and level of consciousness were explored via correlations and regression. Results: Of the 305 cases reviewed, 216 met the criteria for inclusion. The mean temperature was 29.7°C ± 4.2°C (range 19.3°C-34.9°C). The relationships between temperature and each of the four vital signs were generally linear and significantly positive, with Spearman correlations for respiratory rate, heart rate, systolic blood pressure, and Glasgow Coma Score (GCS) of 0.29 (p = 0.024), 0.44 (p < 0.001), 0.47 (p < 0.001), and 0.78 (p < 0.001), respectively. Based on linear regression, the mean decrease of a vital sign associated with a 1°C decrease of temperature was estimated to be 0.50 minute^-1 for respiratory rate, 2.54 minutes^-1 for heart rate, 4.36 mmHg for systolic blood pressure, and 0.88 for GCS. Conclusions: There is a significant positive correlation between core temperature and heart rate, systolic blood pressure, respiratory rate, and GCS. The relationship between vital signs and temperature is generally linear. This knowledge might help clinicians make appropriate decisions when determining whether the clinical condition of a patient should be attributed to hypothermia. This could enhance clinical care and help to guide future research.

Prehospital extracorporeal cardiopulmonary resuscitation for cardiac arrest patients in rural areas: a case report of two patients

Background

The prognosis of out-of-hospital cardiac arrest remains poor, especially for cardiopulmonary arrest patients in rural areas with longer transport duration to hospitals.

Case Presentation

In June 2016, we began providing prehospital extracorporeal life support using a mobile operating room for emergency surgery. We report two patients who survived after receiving prehospital extracorporeal cardiopulmonary resuscitation and were discharged. A patient with cardiopulmonary arrest from accidental hypothermia due to drowning survived with good neurological outcomes after on-site extracorporeal cardiopulmonary resuscitation immediately after rescue. The other patient who survived experienced cardiopulmonary arrest at his workplace, which was approximately 90 min from the center. Prehospital extracorporeal cardiopulmonary resuscitation shortened the cardiopulmonary arrest time by an estimated 30 min, and the patient survived until the hospital.

Conclusion

Prehospital extracorporeal cardiopulmonary resuscitation has the potential to save lives in rural areas by reducing low-flow time.

Using Intra-arterial tPA for Severe Frostbite Cases. An Observational Comparative Retrospective Study

Frostbite causes tissue damage through five major mechanisms, out of which two are amenable to treatment. The first-line treatment is rapid rewarming therapy using water at 40°C to 42°C, which addresses the formation of ice crystals in the intra and extra cellular compartments. The second mechanism is progressive tissue ischemia after rewarming and is only accessible to a second-line therapy represented by thrombolysis. This study aimed to determine the efficacy of thrombolysis. This is a single-center retrospective cohort study, where it was aimed to evaluate two groups of patients. A total of 18 patients were included in this study. Mean times between injury to thrombolytic therapy and admission to thrombolytic therapy was 26.04 hours (SD 13.6) and 9.65 hours (SD 9.89), respectively. All patients suffered injuries ranging from second-degree deep to third degree. The rate of patients having complete, partial, and no angiographic responses were 55.6%, 11.1%, and 33.3%, respectively. The main outcome of interest showed that 11 (61.1%) patients in total had amputations at different levels. Results showed that in the intervention group, five (55.6%) of the patients had amputations compared with six (66.7%) from the control group (P = .6) at comparable levels of amputation. The literature supports that the use of intra-arterial tissue plasminogen activator might be beneficial for severe cases of frostbites; however, it lacks of studies of major significance and results are often controversial. Our study has not shown statistically significant results on amputation levels and cannot support the hypothesis of efficacy of thrombolytic therapy.

Maternal hypothermia from environmental exposure in the third trimester

A primigravida at 32 weeks gestation developed hypothermia after prolonged exposure to the elements at -30.0°C. Her core temperature dropped to 29.8°C with associated foetal bradycardia. Passive rewarming was undertaken with forced warm air blankets and warmed IV fluids. The foetal heart rate normalised once normothermia was achieved. Serial foetal assessments showed appropriate growth and normal Doppler studies. She went to on deliver a healthy term infant. This case highlights conservative management and prioritising of maternal well-being with a good maternal and foetal outcome.

Fetal Bradycardia in Response to Maternal Hypothermia

BACKGROUND

Fetal tachycardia can occur with maternal fever (hyperthermia); therefore, a low maternal temperature (hypothermia) might produce fetal bradycardia.

CASES

Five cases of fetal bradycardia are presented in gestations complicated by maternal hypothermia. The fetal heart rate (FHR) tracings demonstrated stable baselines of 88-96 beats per minute with moderate variability and accelerations. All baselines returned to normal after maternal warming measures.

CONCLUSION

A possible cause for fetal bradycardia with a stable baseline and moderate variability is maternal hypothermia, a pattern not indicative of fetal hypoxia. Delivery is not indicated, and maternal warming results in FHR baseline normalization.

[Emergency medicine in the German Maritime Search and Rescue Service-Evaluation of medical emergencies in the North Sea and Baltic Sea over 2 years]

Hintergrund

Die logistischen Besonderheiten eines maritimen Notfallortes und die häufig zusätzlich drohende akzidentelle Hypothermie machen die Versorgung medizinischer Notfälle auf dem Meer besonders anspruchsvoll. In dieser Arbeit sollen die Charakteristika notfallmedizinischer Einsätze der Deutschen Gesellschaft zur Rettung Schiffbrüchiger (DGzRS) als Hauptträgerin der nichthelikopterbasierten medizinischen Seenotrettung auf den Meeren vor der deutschen Küste beschrieben werden.

Material und Methoden

Es erfolgte eine retrospektive Analyse aller Einsätze der DGzRS der Jahre 2017 und 2018. Die Einsatzdaten und –zeiten sowie die Erkrankungsschwere der Patienten (graduiert mittels NACA-Score) wurden ausgewertet und exemplarisch mit denen eines NEF der Hansestadt Lübeck verglichen.

Ergebnisse

Bei insgesamt 182 medizinischen Einsätzen wurden 224 Patienten behandelt. Die Einsatzeinheiten der DGzRS benötigten im Mittel 30 ± 21 min bis zur Ankunft und 43 ± 30 min für Rettung, Behandlung und Transport. Bei 63 Einsätzen wurden die Patienten durch einen Notarzt betreut, der bei 44 Einsätzen durch die Landrettung herangeführt wurde. Durch die Wartezeit auf bordfremdes Personal wurde bei 26 Einsätzen die Abfahrt um im Mittel 18 ± 7 min verzögert.

Die durchschnittliche Erkrankungsschwere in der Seenotrettung war signifikant höher als im Lübecker Notarztdienst; es gab vergleichbar häufig Reanimationen und Todesfälle.

Schlussfolgerung

Trotz der hohen Krankheitsschwere medizinischer Notfälle auf den Meeren vor Deutschlands Küste treffen Notärzte dort häufig mit erheblicher Verzögerung ein. Es gibt den dringenden Bedarf effektiverer Unterstützung der DGzRS durch für den maritimen Einsatz ausgebildetes ärztliches Personal.

Care at critical care medical centers is associated with improved outcomes in patients with accidental hypothermia: a historical cohort study from the J-Point registry

Aim

The recommendation that patients with accidental hypothermia should be transported to specialized centers that can provide extracorporeal life support has not been validated, and the efficacy remains unclear.

Methods

This was a multicenter retrospective cohort study of patients with a body temperature of ≤35°C presenting at the emergency department of 12 hospitals in Japan between April 2011 and March 2016. We divided the patients into two groups based on the point of care delivery: critical care medical center (CCMC) or non‐CCMC. The primary outcome of this study was in‐hospital death. In‐hospital death was compared using a multivariable logistic regression analysis. Subgroup analyses were carried out according to patients with severe hypothermia (<28°C) or systolic blood pressure (sBP) of <90 mmHg.

Results

A total of 537 patients were included, 413 patients (76.9%) in the CCMC group and 124 patients (23.1%) in the non‐CCMC group. The in‐hospital death rate was lower in the CCMC group than in the non‐CCMC group (22.3% versus 31.5%, P < 0.001). The multivariable logistic regression analysis showed that the adjusted odds ratio (AOR) of the CCMC group was 0.54 (95% confidence interval, 0.32–0.90). In subgroup analyses, patients with systolic blood pressure <90 mmHg in the CCMC group were less likely to experience in‐hospital death (AOR 0.36; 95% CI, 0.23–0.56). However, no such association was observed among patients with severe hypothermia (AOR 1.08; 95% CI, 0.63–1.85).

Conclusions

Our multicenter study indicated that care at a CCMC was associated with improved outcomes in patients with accidental hypothermia.

Impact of body temperature at admission on inhospital outcomes in patients with takotsubo syndrome: insights from the Tokyo Cardiovascular Care Unit Network Registry

Background:

Takotsubo syndrome occasionally occurs in patients with fever due to underlying diseases. However, the impact of body temperature on inhospital prognosis of patients with takotsubo syndrome remains unknown.

Methods:

Using the patient cohort in the Tokyo Cardiovascular Care Unit Network Registry from 2013 to 2015, we identified 421 eligible patients whose data on body temperature at admission were available and classified them into three groups: high body temperature group (≥37.5°C; n=27), normal body temperature group (36.0–37.4°C; n=319), and low body temperature group (≤35.9°C; n=75). We compared the patient characteristics and inhospital outcomes among the three groups.

Results:

On admission, the high body temperature group showed a higher proportion of men and preceding physical triggers, higher heart and respiratory rates, and higher C-reactive protein level than the other groups. Inhospital all-cause mortality was significantly higher in the high body temperature group than in the normal or low body temperature group (18.5% vs. 2.2% vs. 4.0%, respectively, P&lt;0.001). Both cardiac mortality (11.1% vs. 1.3% vs. 1.3%, P=0.001) and non-cardiac mortality (7.4% vs. 0.9% vs. 2.7%, P=0.031) were also significantly higher in the high body temperature group. Multivariable logistic regression analysis showed that high body temperature (reference: normal body temperature) was significantly associated with higher inhospital mortality (adjusted odds ratio 4.22; 95% confidence interval 1.15–15.51; P=0.030).

Conclusions:

Our findings suggest that high body temperature at admission is a strong predictor of inhospital mortality in patients with takotsubo syndrome. Febrile takotsubo syndrome patients may need to be managed with recognition of life-threatening conditions from the time of diagnosis, no matter what the causes of fever are.

The Impact of Accidental Hypothermia on Mortality in Trauma Patients Overall and Patients with Traumatic Brain Injury Specifically: A Systematic Review and Meta-Analysis

Background

Accidental hypothermia is a known predictor for worse outcomes in trauma patients, but has not been comprehensively assessed in a meta-analysis so far. The aim of this systematic review and meta-analysis was to investigate the impact of accidental hypothermia on mortality in trauma patients overall and patients with traumatic brain injury (TBI) specifically.

Methods

This is a systematic review and meta-analysis using the Ovid Medline/PubMed database. Scientific articles reporting accidental hypothermia and its impact on outcomes in trauma patients were included in qualitative synthesis. Studies that compared the effect of hypothermia vs. normothermia at hospital admission on in-hospital mortality were included in two meta-analyses on (1) trauma patients overall and (2) patients with TBI specifically. Meta-analysis was performed using a Mantel–Haenszel random-effects model.

Results

Literature search revealed 264 articles. Of these, 14 studies published 1987–2018 were included in the qualitative synthesis. Seven studies qualified for meta-analysis on trauma patients overall and three studies for meta-analysis on patients with TBI specifically. Accidental hypothermia at admission was associated with significantly higher mortality both in trauma patients overall (OR 5.18 [95% CI 2.61–10.28]) and patients with TBI specifically (OR 2.38 [95% CI 1.53–3.69]).

Conclusions

In the current meta-analysis, accidental hypothermia was strongly associated with higher in-hospital mortality both in trauma patients overall and patients with TBI specifically. These findings underscore the importance of measures to avoid accidental hypothermia in the prehospital care of trauma patients.

Electronic supplementary material

The online version of this article (10.1007/s00268-020-05750-5) contains supplementary material, which is available to authorized users.

Pediatric hypothermic submersion incident - should we do chest compressions on a beating heart?

Background

Drowning is the third leading cause of unintentional injury death worldwide, with the highest rates of fatality among young children. To decide how to treat these patients prehospitally could be challenging in certain situations when uncertain about the adequacy of the patent’s circulation.

Methods/case report

We describe a 2 year old boy surviving a 15 min hypothermic submersion in a cold river. In spite of the presence of some vital signs, we decided to do full cardiopulmonary resuscitation to the hospital. The main reason was that we were uncertain about the adequacy of the spontaneous circulation, and the transport to hospital was fairly long. The patient suffered no obvious harm and the outcome was good.

Discussion

What is regarded as adequate circulation when accidentally hypothermic between 24 and 25⁰ C? A weak pulse was felt in the femoral artery with a rate of about 40–50 per minute. There were shallow, but regular respiration, and point of care ultrasound revealed a slightly dilated left ventricle and weak, but organised cardiac contractions. Despite these findings a decision was made to continue ventilations and chest compressions during helicopter transport to the University hospital.

Conclusion

In an accidentally hypothermic pediatric submersion incident we decided to do full cardiopulmonary resuscitation to the hospital despite there were signs of circulation. We did no harm to the patient. Future guideline revisions should try to clarify how to handle situations with severly accidentally hypothermic patients like this, so the good outcome that is often seen in these patients could be even better.

Predictive accuracy of biomarkers for survival among cardiac arrest patients with hypothermia: a prospective observational cohort study in Japan

Background

There is limited information on the predictive accuracy of commonly used predictors, such as lactate, pH or serum potassium for the survival among out-of-hospital cardiac arrest (OHCA) patients with hypothermia. This study aimed to identify the predictive accuracy of these biomarkers for survival among OHCA patients with hypothermia.

Methods

In this retrospective analysis, we analyzed the data from a multicenter, prospective nationwide registry among OHCA patients transported to emergency departments in Japan (the JAAM-OHCA Registry). We included all adult (≥18 years) OHCA patients with hypothermia (≤32.0 °C) who were registered from June 2014 to December 2017 and whose blood test results on hospital arrival were recorded. We calculated the predictive accuracy of pH, lactate, and potassium for 1-month survival.

Results

Of the 34,754 patients in the JAAM-OHCA database, we included 754 patients from 66 hospitals. The 1-month survival was 5.8% (44/754). The areas under the curve of the predictors and 95% confidence interval were as follows: pH 0.829 [0.767–0.877] and lactate 0.843 [0.793–0.882]. On setting the cutoff points of 6.9 in pH and 120 mg/dL (13.3 mmol/L) in lactate, the predictors had a high sensitivity (lactate: 0.91; pH 0.91) and a low negative likelihood ratio (lactate: 0.14; pH 0.13), which are suitable to exclude survival to 1 month. Furthermore, in additional analysis that included only the patients with potassium values available, a cutoff point of 7.0 (mmol/L) for serum potassium had high sensitivity (0.96) and a low negative likelihood ratio (0.09).

Conclusion

This study indicated the predictive accuracy of serum lactate, pH, and potassium for 1-month survival among adult OHCA patients with hypothermia. These biomarkers may help define a more appropriate resuscitation strategy.

Outcomes of Extracorporeal Life Support Use in Accidental Hypothermia: A Systematic Review

BACKGROUND

Extracorporeal life support (ECLS) has been used in the treatment of accidental hypothermia with hemodynamic instability, with promising outcomes. This systematic review examines ECLS treatment of accidental hypothermia to assess outcomes.

METHODS

An electronic search was performed to identify articles reporting ECLS use for treatment of accidental hypothermia. Only reports describing patients aged more than 16 years after January 1, 2005, were included. Nineteen studies were identified comprising 47 patients. Demographic information, perioperative variables, and outcomes were extracted for analysis.

RESULTS

Median patient age was 48 years (interquartile range (IQR), 29 to 56), and 72.3% (34 of 47) were male. On presentation, median body temperature was 24.6°C (IQR, 22.2° to 26°C), median potassium level 4.3 mmol/L (IQR, 3.4 to 4.6 mmol/L), and median Glasgow Coma Scale score 3 (IQR, 3 to 7). Cardiac arrest occurred in 35 of 47 patients (74.5%). Median time to ECLS initiation from scene was 155 minutes (IQR, 113 to 245). Median ECLS duration was 18 hours (IQR, 4 to 27), with median rewarming rate of 2°C per hour (IQR, 1.5° to 4°). Median intensive care unit stay and hospital length of stay were 8 days (IQR, 2 to 16) and 17 days (IQR, 10 to 36), respectively. Inhospital mortality was 19.1% (9 of 47). Median discharge Glasgow Coma Scale score was 15 (IQR, 15 to 15) with minor long-term cognitive impairments noted in 6 of 47 patients (19.4%). Survival was significantly associated with potassium on presentation (P < .001), initial body temperature (P < .001), and ECLS rewarming rate (P < .001).

CONCLUSIONS

Extracorporeal life support is a viable cardiac support option for rewarming patients with accidental hypothermia, and initial potassium level, initial body temperature, and ECLS rewarming rate appear to be significantly associated with survival.

Accidental hypothermic cardiac arrest and extracorporeal membrane oxygenation: a case report

BACKGROUND

Accidental hypothermic cardiac arrest, an involuntary drop in core body temperature resulting in cardiopulmonary arrest, is linked to 1500 deaths annually. We highlight the challenges with the treatment of accidental hypothermic cardiac arrest and describe improved preparations necessary for an integrated health system to care for similar patients.

CASE REPORT

Emergency medical services (EMS) were dispatched to a 34-year-old female who had been missing for several hours during a January snowfall. The patient was found unconscious over an embankment. The patient was found with a weak carotid pulse and two empty bottles of clozapine, an atypical antipsychotic. The EMS crew extricated the patient, performed a rapid trauma assessment, passive rewarming, and airway management. During transport, the patient suffered a ventricular fibrillation cardiac arrest, received defibrillation, and advanced life support measures. Resuscitative efforts continued in the emergency department while the treatment team addressed environmental exposure, assessed for traumatic injury and toxicologic exposure. On emergency department (ED) arrival, the patient's core temperature was 24°C, and despite aggressive resuscitation, the patient remained in cardiac arrest. The ED care team used extracorporeal membrane oxygenator (ECMO) and successfully resuscitated the patient with extracorporeal cardiopulmonary resuscitation. The patient achieved full neurologic recovery 15 days post-ED arrival.

CONCLUSION

This case highlights the importance of early recognition of accidental hypothermic cardiac arrest by EMS clinicians, rapid transport to a tertiary facility, and the timely application of active rewarming and in-hospital ECMO. Accidental hypothermic cardiac arrest is a reversible state; prompt and correct treatment allows for a high probability of a favorable neurologic outcome.

Factors associated with severity of accidental hypothermia: A cohort retrospective multi-institutional study

Background

Frequently it is difficult to determine illness severity in hypothermic patients. Our goal was to determine if there are factors associated with illness severity of hypothermic emergency department (ED) patients.

Methods

Multi-hospital retrospective cohort. Consecutive patients in 24 EDs (1-1-2012 to 4-30–2015). Hypothermic patients (≤35 °C) were identified using ICD codes. We used hospital admission as marker of illness severity. Student's t-test was used for differences between mean age and temperature for admitted and discharged patients. We calculated the percent of patients admitted by factor, the difference from overall admission rate and 95% confidence interval (CI) of difference.

Results

There were 2094 visits with hypothermia ICD code. Of these, 132 patients had initial rectal temperatures ≤35 °C. Females comprised 42%; the mean age was 55 ± 23 years, and overall admission rate was 62%. The percent of patients with alcohol, trauma and found indoors were 39%, 27% and 27%, respectively. For admitted and discharged patients the mean ages were 60 and 48 years, respectively (p = 0.01), and initial mean temperature 32.3 °C vs. 33 °C, respectively (p = 0.07). Found indoors was associated with an 86% admission rate, a 22% increase (95% CI, 3%–34%) compared to overall admission rate. There was no statistically significant difference in admission rates from overall admission rate based on gender, alcohol or trauma.

Conclusions

For hypothermic ED patients increased severity of illness was associated with older age and found indoors but not associated with initial temperature, gender, alcohol or trauma. These findings may assist physicians in treatment and disposition decisions.

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Accidental hypothermia is defined as a decrease in core body temperature to less than 35°C (95°F).

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Secondary hypothermia can occur in healthy and ill persons, even in warm environments, as a result of predisposing factors.

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Maintenance of a normal core temperature is achieved from a balance between heat production and heat loss.

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Factors associated with increased severity of illness for hypothermic ED patients were older age and found indoors.

Cardiac Arrest Secondary to Accidental Hypothermia: Who Should We Resuscitate?

Cardiac arrest with a degree of concurrent hypothermia is not a rare presentation. This presentation, often in remote areas, poses a challenge for the prehospital physician because the cause of the arrest will significantly alter decision making and prognostication. Survival from cardiac arrest secondary to accidental hypothermia is significantly greater than that of normothermic arrests when appropriate triage and management decisions are made. The complexity of this decision benefits from a specific algorithm to follow in the event of such a casualty presenting. This article systematically reviews the literature on cardiac arrest secondary to accidental hypothermia and provides recommendations in addition to a novel algorithm to aid the responding prehospital clinician in deciding if a hypothermic resuscitation standard operating procedure should be implemented.

Hypothermia and cardiac electrophysiology: a systematic review of clinical and experimental data

Moderate therapeutic hypothermia procedures are used in post-cardiac arrest care, while in surgical procedures, lower core temperatures are often utilized to provide cerebral protection. Involuntary reduction of core body temperature takes place in accidental hypothermia and ventricular arrhythmias are recognized as a principal cause for a high mortality rate in these patients. We assessed both clinical and experimental literature through a systematic literature search in the PubMed database, to review the effect of hypothermia on cardiac electrophysiology. From included studies, there is common experimental and clinical evidence that progressive cooling will induce changes in cardiac electrophysiology. The QT interval is prolonged and appears more sensitive to decreases in temperature than the QRS interval. Severe hypothermia is associated with more pronounced changes, some of which are proarrhythmic. This is supported clinically where severe accidental hypothermia is commonly associated with ventricular fibrillation or asystole. J-waves in human electrocardiogram recordings are regularly but not always observed in hypothermia. Its relation to ventricular repolarization and arrhythmias is not obvious. Little clinical data exist on efficacy of anti-arrhythmic drugs in hypothermia, while experimental data show the potential of some agents, such as the class III antiarrhythmic bretylium. It is apparent that QT-prolonging drugs should be avoided.

Hypothermia Associated With Melatonin Ingestion in a Child With Autism

Autism spectrum disorder is a neurodevelopmental disorder characterized by social interaction and communication disorder and restrictive and repetitive behaviors. Sleep disorders are frequently observed in children with autism spectrum disorder. We present a case of hypothermia in an autistic child with a sleep disorder whose body temperature decreased to 34°C after a single dose of melatonin. Hypothermia continued for 2 more days, but her nighttime sleeping problems decreased. This case is important because it demonstrates the possible risk of hypothermia with melatonin use in children with autism with a sleep disorder.

Cardiac Arrest Secondary to Accidental Hypothermia: The Physiology Leading to Hypothermic Arrest

Cardiac arrest secondary to accidental hypothermia is rare in the United Kingdom. However, some evidence suggests that it is under-reported; furthermore, recognizing hypothermia as the cause of death is difficult in the postmortem setting. Urban and rural residents are exposed to cold winter conditions both at home and while undertaking recreational activities. Understanding the physiology underpinning hypothermic cardiac arrest is crucial in order to make informed clinical decisions in regard to triage and management by air ambulance services and in prevention of this rare presentation. This article discusses the epidemiology and pathophysiology of accidental hypothermic to explain how personnel can survive after 8 hours 40 minutes of cardiac arrest.

Molecular mechanisms of Wischnewski spot development on gastric mucosa in fatal hypothermia: an experimental study in rats

Numerous dark-brown-coloured small spots called “Wischnewski spots” are often observed in the gastric mucosa in the patients dying of hypothermia, but the molecular mechanisms through which they develop remain unclear. We hypothesised that hypothermia may activate the secretion of gastric acid and pepsin, leading to the development of the spots. To investigate this, we performed experiments using organotypic rat gastric tissue slices cultured at 37 °C (control) or 32 °C (cold). Cold loading for 6 h lowered the extracellular pH in the culture medium. The mRNA expression of gastrin, which regulates gastric acid secretion, increased after cold loading for 3 h. Cold loading increased the expression of gastric H⁺,K⁺-ATPase pump protein in the apical canalicular membrane and resulted in dynamic morphological changes in parietal cells. Cold loading resulted in an increased abundance of pepsin C protein and an elevated mRNA expression of its precursor progastricsin. Collectively, our findings clarified that cold stress induces acidification by activating gastric H⁺,K⁺-ATPase pumps and promoting pepsin C release through inducing progastricsin expression on the gastric mucosa, leading to tiny haemorrhages or erosions of the gastric mucosa that manifest as Wischnewski spots in fatal hypothermia.

Osborn Wave Is Related to Ventricular Fibrillation and Tachycardia in Hypothermic Patients

BACKGROUND

The Osborn wave (OW) is often observed in hypothermic patients; however, whether OW in hypothermic patients is related to the development of fatal ventricular arrhythmia, including ventricular fibrillation (VF) and pulseless ventricular tachycardia (VT), remains undetermined. This study aimed to estimate the association between OW and the incidence of fatal ventricular arrhythmias.Methods and Results: This retrospective study used the Japanese Accidental Hypothermia Network registry database and included 572 hypothermic patients. Patients were divided into the OW group (those with OW) and non-OW group (those without OW). The relationship between the development of fatal arrhythmias and presence of OW was assessed using the chi-squared test. All patients who developed VF/VT (n=10) had OW on electrocardiogram upon hospital arrival. The presence of OW had a sensitivity of 100%, specificity of 47.8%, positive predictive value of 4.0%, and negative predictive value of 100% for VF/VT development. The in-hospital mortality rate was 22.3% in the OW group and 21.2% in the non-OW group (P=0.781).

CONCLUSIONS

OW was observed in all hypothermic patients with VF/VT. The occurrence of ventricular arrhythmias is highly unlikely in the absence of OW on the electrocardiogram. Although the presence of OW might be used to predict these fatal arrhythmias in hypothermic patients, there was no association between the presence of OW and in-hospital mortality.

Cardiac Arrest Secondary to Accidental Hypothermia: Rewarming Strategies in the Field

Hypothermic cardiac arrest is rare and poses a challenge to prehospital responders. Standard cardiac arrest protocols advise treating reversible causes of arrest; however, rewarming the cold casualty is not easily achieved in the field. This article aimed to review the literature on hypothermia in order to produce evidence-based recommendations on rewarming that could realistically be applied to hypothermic cardiac arrest patients.

Thermoregulatory, metabolic, and cardiovascular responses during 88 min of full-body ice immersion - A case study

Exposure to extreme cold environments is potentially life-threatening. However, the world record holder of full-body ice immersion has repeatedly demonstrated an extraordinary tolerance to extreme cold. We aimed to explore thermoregulatory, metabolic, and cardiovascular responses during 88 min of full-body ice immersion. We continuously measured gastrointestinal temperature (T_gi ), skin temperature (Tskin), blood pressure, and heart rate (HR). Oxygen consumption (VO₂ ) was measured at rest, and after 45 and 88 min of ice immersion, in order to calculate the metabolic heat production. Tskin dropped significantly (28-34°C to 4-15°C) and VO₂ doubled (5.7-11.3 ml kg^-1  min^-1 ), whereas Tgi (37.6°C), HR (72 bpm), and mean arterial pressure (106 mmHg) remained stable during the first 30 min of cold exposure. During the remaining of the trial, Tskin and VO₂ remained stable, while Tgi gradually declined to 37.0°C and HR and mean arterial blood pressure increased to maximum values of 101 bpm and 115 mmHg, respectively. Metabolic heat production in rest was 169 W and increased to 321 W and 314 W after 45 and 80 min of ice immersion. Eighty-eight minutes of full-body ice immersion resulted in minor changes of Tgi and cardiovascular responses, while Tskin and VO₂ changed markedly. These findings may suggest that our participant can optimize his thermoregulatory, metabolic, and cardiovascular responses to challenge extreme cold exposure.

Management of Multiple Sclerosis Symptoms and Comorbidities

PURPOSE OF REVIEW

This article discusses the prevalence, identification, and management of multiple sclerosis (MS)-related symptoms and associated comorbidities, including complications that can present at all stages of the disease course.

RECENT FINDINGS

The impact of comorbidities on the outcome of MS is increasingly recognized. This presents an opportunity to impact the course and outcome of MS by identifying and treating associated comorbidities that may be more amenable to treatment than the underlying inflammatory and neurodegenerative disease. The identification of MS-related symptoms and comorbidities is facilitated by brief screening tools, ideally completed by the patient and automatically entered into the patient record, with therapeutic suggestions for the provider. The development of free, open-source screening tools that can be integrated with electronic health records provides opportunities to identify and treat MS-related symptoms and comorbidities at an early stage.

SUMMARY

Identification and management of MS-related symptoms and comorbidities can lead to improved outcomes, improved quality of life, and reduced disease activity. The use of brief patient-reported screening tools at or before the point of care can facilitate identification of symptoms and comorbidities that may be amenable to intervention.

Derivation of a model to predict mortality in urban patients with accidental hypothermia: a retrospective observational study

Aim

Accidental hypothermia in urban settings is associated with high mortality rates. However, the predictors of mortality remain under discussion. The purpose of this study was to evaluate prognostic factors and develop a prediction model in patients with accidental hypothermia in urban settings.

Methods

We retrospectively reviewed medical records in patients with hypothermia brought to our hospital by ambulance in a 7-year study period. Patients' records of survival discharge or in-hospital death and clinical data were collected from medical records. We analyzed factors to predict in-hospital death using multiple logistic regression analysis. Recursive partitioning analysis was used to construct a prediction model using predictors from multiple logistic regression analysis.

Results

In the study period, 192 patients were included in this study. Of them, 154 patients were discharged alive and 38 patients died. Multiple logistic regression analysis revealed that in-hospital death was related to Glasgow Coma Scale (GCS) score, prothrombin time - international normalized ratio (PT-INR) value, and fibrin degradation product (FDP). Recursive partitioning analysis revealed that patients with accidental hypothermia could be divided into four groups: very high risk (FDP ≥ 14 µg/mL, PT-INR ≥ 1.4), high risk (FDP ≥ 14 µg/mL, PT-INR < 1.4), moderate risk (FDP < 14 µg/mL, GCS < 10), and low risk (FDP < 14 µg/mL, GCS ≥ 10).

Conclusion

High FDP and PT-INR values and low GCS score on arrival at the emergency department were associated with in-hospital mortality in urban patients with hypothermia. A simple prediction model for grouping risk was developed using these predictors.