The impact of hypothermia on serum potassium concentration: A systematic review

Triage body temperature and its influence on patients with acute myocardial infarction

BACKGROUND

Fever can occur after acute myocardial infarction (MI). The influence of body temperature (BT) after hospital arrival on patients with acute MI has rarely been investigated.

METHODS

Patients who were diagnosed with acute MI in the emergency department (ED) of a tertiary teaching hospital between 1 January 2020 and 31 December 2020 were enrolled. Based on the tympanic temperature obtained at the ED triage, patients were categorized into normothermic (35.5°C-37.5°C), hypothermic (< 35.5°C), or hyperthermic (> 37.5°C) groups. The primary outcome was in-hospital cardiac arrest (IHCA), while the secondary outcomes were adverse events. Statistical significance was set at p < 0.05.

RESULTS

There were 440 enrollees; significant differences were found among the normothermic (n = 369, 83.9%), hypothermic (n = 27, 6.1%), and hyperthermic (n = 44, 10.0%) groups in the triage respiratory rate (median [IQR]) (20.0 [4.0] cycles/min versus 20.0 [4.0] versus 20.0 [7.5], p = 0.009), triage heart rate (88.0 [29.0] beats/min versus 82.0 [28.0] versus 102.5 [30.5], p < 0.001), presence of ST-elevation MI (42.0% versus 66.7% versus 31.8%, p = 0.014), need for cardiac catheterization (87.3% versus 85.2% versus 72.7%, p = 0.034), initial troponin T level (165.9 [565.2] ng/L versus 49.1 [202.0] versus 318.8 [2002.0], p = 0.002), peak troponin T level (343.8 [1405.9] ng/L versus 218.7 [2318.2] versus 832.0 [2640.8], p = 0.003), length of ICU stay (2.0 [3.0] days versus 3.0 [8.0] versus 3.0 [9.5], p = 0.006), length of hospital stay (4.0 [4.5] days versus 6.0 [15.0] versus 10.5 [10.8], p < 0.001), and infection during hospitalization (19.8% versus 29.6% versus 63.6%, p < 0.001) but not in IHCA (7.6% versus 14.8% versus 11.4%, p = 0.323) or any adverse events (50.9% versus 48.1% versus 63.6%, p = 0.258). Multivariable analysis showed no significant association of triage BT with IHCA or any major complication.

CONCLUSION

Triage BT did not show a significant association with IHCA or adverse events in patients with acute MI. However, triage BT could be associated with different clinical presentations and should warrant further investigation.

Extracorporeal Rewarming Is Associated With Increased Survival Rate in Severely Hypothermic Patients With Preserved Spontaneous Circulation

Treatment recommendations for rewarming patients in severe accidental hypothermia with preserved spontaneous circulation have a weak evidence due to the absence of randomized clinical trials. We aimed to compare the outcomes of extracorporeal versus less-invasive rewarming of severely hypothermic patients with preserved spontaneous circulation. We conducted a multicenter retrospective study. The patient population was compiled based on data from the HELP Registry, the International Hypothermia Registry, and a literature review. Adult patients with a core temperature <28°C and preserved spontaneous circulation were included. Patients who underwent extracorporeal rewarming were compared with patients rewarmed with less-invasive methods, using a matched-pair analysis. The study population consisted of 50 patients rewarmed extracorporeally and 85 patients rewarmed with other, less-invasive methods. Variables significantly associated with survival included: lower age; outdoor cooling circumstances; higher blood pressure; higher PaCO 2 ; higher BE; higher HCO 3 ; and the absence of comorbidities. The survival rate was higher in patients rewarmed extracorporeally ( p = 0.049). The relative risk of death was twice as high in patients rewarmed less invasively. Based on our data, we conclude that patients in severe accidental hypothermia with circulatory instability can benefit from extracorporeal rewarming without an increased risk of complications.

Serum potassium changes during hypothermia and rewarming: a case series and hypothesis on the mechanism

Introduction

Hypokalemia is known to occur in association with therapeutically induced hypothermia and is usually managed by the administration of potassium (K+).

Methods

We reviewed data from 74 patients who underwent a therapeutic hypothermia protocol at our medical institution.

Results

In four patients in whom data on serum K+ and temperature were available, a strong positive correlation between serum K+ and body temperature was found. Based on the close positive relationship between serum K+ and total body temperature, we hypothesize that serum K+ decreases during hypothermia owing to decreased activity of temperature-dependent K+ exit channels that under normal conditions are sufficiently active to match cellular K+ intake via sodium/K+/adenosine triphosphatase. Upon rewarming, reactivation of these channels results in a rapid increase in serum K+ as a result of K+ exit down its concentration gradient.

Conclusion

Administration of K+ during hypothermia should be done cautiously and avoided during rewarming to avoid potentially life-threatening hyperkalemia. K+ exit via temperature-dependent K+ channels provides a logical explanation for the rebound hyperkalemia. K+ exit channels may play a bigger role than previously appreciated in the regulation of serum K+ during normal and pathophysiological conditions.

The hypokalaemia that came from the cold

While electrolyte disorders are common in nephrologists' clinical practice, hypothermia is a condition that nephrologists rarely encounter. Hypothermia can induce several pathophysiological effects on the human body, including hypokalaemia, which is reversible with rewarming. Despite growing evidence from animal research and human studies, the underlying mechanisms of hypothermia-induced hypokalaemia remain unclear. Boubes and colleagues recently presented a case series of hypokalaemia during hypothermia and rewarming, proposing a novel hypothesis for the underlying mechanisms. In this editorial, we review the current knowledge about hypothermia and associated electrolyte changes with insights into the effects of hypothermia on renal physiology.

Electrolyte considerations in targeted temperature management

PURPOSE

Targeted temperature management (TTM), including normothermia and therapeutic hypothermia, is used primarily for comatose patients with return of spontaneous circulation after cardiac arrest or following neurological injury. Despite the potential benefits of TTM, risks associated with physiological alterations, including electrolyte shifts, may require intervention.

SUMMARY

This review describes the normal physiological balance of electrolytes and temperature-related alterations as well as the impact of derangements on patient outcomes, providing general recommendations for repletion and monitoring of key electrolytes, including potassium, phosphate, and magnesium.

CONCLUSION

Frequent monitoring and consideration of patient variables such as renal function and other risk factors for adverse effects are important areas of awareness for clinicians caring for patients undergoing TTM.

Non-Selective PDE4 Inhibition Induces a Rapid and Transient Decrease of Serum Potassium in Mice

Simple Summary

Inhibitors of phosphodiesterase 4 (PDE4), a group of isoenzymes that hydrolyze and inactivate the second messenger cAMP, produce promising therapeutic benefits, including anti-inflammatory and memory-enhancing effects. Here, we report that, unexpectedly, PDE4 inhibitors also reduce serum potassium levels in mice. As both the total potassium content of the body, as well as the distribution of potassium between intra- and extracellular compartments, are critical for normal cellular functions, we further explored this observation. Several structurally distinct PDE4 inhibitors reduce serum potassium levels in mice, suggesting it is a class effect of these drugs. Serum potassium levels decrease within 15 min of drug injection, suggesting that PDE4 inhibition lowers serum potassium levels by promoting a transcellular shift of potassium from the blood into cells. This shift is a characteristically fast process, compared to a loss of total-body potassium via the kidneys or digestive tract (e.g., diarrhea). Indeed, stimulating cAMP synthesis with β-adrenoceptor agonists is known to rapidly shift potassium into cells, and PDE4 inhibitors appear to mimic this process by preventing PDE4-mediated cAMP degradation. Our findings reveal that the various acute physiologic effects of PDE4 inhibitors are paralleled and/or may be affected by reduced serum potassium levels.

Abstract

The analysis of blood samples from mice treated with the PDE4 inhibitor Roflumilast revealed an unexpected reduction in serum potassium levels, while sodium and chloride levels were unaffected. Treatment with several structurally distinct PAN-PDE4 inhibitors, including Roflumilast, Rolipram, RS25344, and YM976 dose-dependently reduced serum potassium levels, indicating the effect is a class-characteristic property. PDE4 inhibition also induces hypothermia and hypokinesia in mice. However, while general anesthesia abrogates these effects of PDE4 inhibitors, potassium levels decrease to similar extents in both awake as well as in fully anesthetized mice. This suggests that the hypokalemic effects of PDE4 inhibitors occur independently of hypothermia and hypokinesia. PDE4 inhibition reduces serum potassium within 15 min of treatment, consistent with a rapid transcellular shift of potassium. Catecholamines promote the uptake of potassium into the cell via increased cAMP signaling. PDE4 appears to modulate these adrenoceptor-mediated effects, as PDE4 inhibition has no additional effects on serum potassium in the presence of saturating doses of the β-adrenoceptor agonist Isoprenaline or the α₂-blocker Yohimbine, and is partially blocked by pre-treatment with the β-blocker Propranolol. Together, these data suggest that PDE4 inhibitors reduce serum potassium levels by modulating the adrenergic regulation of cellular potassium uptake.

Sellke F, Feng J. Potassium and Cardiac Surgery

Potassium homeostasis affects cardiac rhythm and contractility, along with vascular reactivity and vascular smooth muscle proliferation. This chapter will focus on potassium dynamics during and after cardiac surgery involving cardioplegic arrest and cardiopulmonary bypass (CPB). Hyperkalemic, hypothermic solutions are frequently used to induce cardioplegic arrest and protect the heart during cardiac surgery involving CPB. Common consequences of hyperkalemic cardioplegic arrest and reperfusion include microvascular dysfunction involving several organ systems and myocardial dysfunction. Immediately after CPB, blood potassium levels often drop precipitously due to a variety of factors, including CPB -induced electrolyte depletion and frequent, long-term administration of insulin during and after surgery. Meanwhile, some patients with pre-existing kidney dysfunction may experience postoperative hyperkalemia following cardioplegia. Any degree of postoperative hyper/hypokalemia significantly elevates the risk of cardiac arrythmias and subsequent myocardial failure. Therefore, proper management of blood potassium levels during and after cardioplegia/CPB is crucial for optimizing patient outcomes following cardiac surgery.

N-Acetyl-L-Cysteine Protects Organ Function After Hemorrhagic Shock Combined With Seawater Immersion in Rats by Correcting Coagulopathy and Acidosis

Background

The mortality of trauma combined with seawater immersion is higher than that of land injury, however, research on how to treat this critical case and which treatments to adopt is lacking.

Methods

The effect of the thiol compound, N-acetyl-L-Cysteine (NAC), on survival, acidosis, coagulopathy, vital signs, oxidative stress, and mitochondrial and multi-organ function was assessed in a rat model of hemorrhagic shock combined with seawater immersion (Sea-Shock).

Results

Hemorrhagic shock combined with seawater immersion caused a severe lethal triad: multi-organ impairment, oxidative stress, and mitochondrial dysfunction. NAC (30 mg/kg) with lactated Ringer’s (LR) solution (2 × blood volume lost) significantly improved outcomes compared to LR or hetastarch (HES 130/0.4) alone. NAC significantly prolonged survival time to 52.48 ± 30.09 h and increased 72 h survival rate to 11/16 (68%). NAC relieved metabolic acidosis and recovered the pH back to 7.33. NAC also restored coagulation, with APTT, PT, and PT-INR decreased by 109.31, 78.09, and 73.74%, respectively, while fibrinogen level increased 246.23% compared with untreated Sea-Shock. Administration of NAC markedly improved cardiac and liver function, with some improvement of kidney function.

Conclusion

The addition of NAC to crystalloid resuscitation fluid alleviated oxidative stress, restored redox homeostasis, and provided multi-organ protection in the rats after Sea-Shock. NAC may be an effective therapeutic measure for hemorrhagic shock combined with seawater immersion.

Hypothermia as an adjuvant treatment in paediatric refractory or super-refractory status epilepticus

Therapeutic hypothermia is among the adjuvant therapies suggested for refractory or super-refractory status epilepticus (R/SR-SE) in paediatric patients. Experimental evidence of neuroprotective and antiseizure effects provides a strong rationale for using therapeutic hypothermia in patients with status epilepticus. Thus, hypothermia between 20°C and 33°C in animals with status epilepticus is associated not only with significantly less neuronal damage, predominantly in the hippocampal CA1, CA2, and CA3 areas, but also with increased seizure latency and decreased seizure frequency and duration. Therapeutic hypothermia has rarely been used in paediatric R/SR-SE. In the few reported cases, seizure control was markedly improved but nearly half the patients experienced recurrences after rewarming. Studies are needed to clarify the modalities and indications of therapeutic hypothermia in paediatric patients with R/SR-SE. WHAT THIS PAPER ADDS: Hypothermia at 20°C to 33°C is neuroprotective and has antiseizure effects in experimental status epilepticus. In children, antiseizure effects are marked but recurrences after rewarming are common.

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.

Intravascular Cooling Device Versus Esophageal Heat Exchanger for Mild Therapeutic Hypothermia in an Experimental Setting

BACKGROUND

Targeted temperature management is a standard therapy for unconscious survivors of cardiac arrest. To date, multiple cooling methods are available including invasive intravascular cooling devices (IVDs), which are widely used in the clinical setting. Recently, esophageal heat exchangers (EHEs) have been developed providing cooling via the esophagus that is located close to the aorta and inferior vena cava. The objective was to compare mean cooling rates, as well as differences, to target temperature during maintenance and the rewarming period of IVD and EHE.

METHODS

The study was conducted in 16 female domestic pigs. After randomization to either IVD or EHE (n = 8/group), core body temperature was reduced to 33°C. After 24 hours of maintenance (33°C), animals were rewarmed using a target rate of 0.25°C/h for 10 hours. All cooling phases were steered by a closed-loop feedback system between the internal jugular vein and the chiller. After euthanasia, laryngeal and esophageal tissue was harvested for histopathological examination.

RESULTS

Mean cooling rates (4.0°C/h ± 0.4°C/h for IVD and 2.4°C/h ± 0.3°C/h for EHE; P < .0008) and time to target temperature (85.1 ± 9.2 minutes for IVD and 142.0 ± 21.2 minutes for EHE; P = .0008) were different. Mean difference to target temperature during maintenance (0.07°C ± 0.05°C for IVD and 0.08°C ± 0.10°C for EHE; P = .496) and mean rewarming rates (0.2°C/h ± 0.1°C/h for IVD and 0.3°C/h ± 0.2°C/h for EHE; P = .226) were similar. Relevant laryngeal or esophageal tissue damage could not be detected. There were no significant differences in undesired side effects (eg, bradycardia or tachycardia, hypokalemia or hyperkalemia, hypoglycemia or hyperglycemia, hypotension, overcooling, or shivering).

CONCLUSIONS

After insertion, target temperatures could be reached faster by IVD compared to EHE. Cooling performance of IVD and EHE did not significantly differ in maintaining target temperature during a targeted temperature management process and in active rewarming protocols according to intensive care unit guidelines in this experimental setting.

Intra-patient potassium variability after hypothermic cardiac arrest: a multicentre, prospective study

Background

To date, the decision to set up therapeutic extra-corporeal life support (ECLS) in hypothermia-related cardiac arrest is based on the potassium value only. However, no information is available about how the analysis should be performed. Our goal was to compare intra-individual variation in serum potassium values depending on the sampling site and analytical technique in hypothermia-related cardiac arrests.

Methods

Adult patients with suspected hypothermia-related refractory cardiac arrest, admitted to three hospitals with ECLS facilities were included. Blood samples were obtained from the femoral vein, a peripheral vein and the femoral artery. Serum potassium was analysed using blood gas (BGA) and clinical laboratory analysis (CL).

Results

Of the 15 consecutive patients included, 12 met the principal criteria, and 5 (33%) survived. The difference in average potassium values between sites or analytical method used was ≤1 mmol/L. The agreement between potassium values according to the three different sampling sites was poor. The ranges of the differences in potassium using BGA measurement were − 1.6 to + 1.7 mmol/L; − 1.18 to + 2.7 mmol/L and − 0.87 to + 2 mmol/L when comparing respectively central venous and peripheral venous, central venous and arterial, and peripheral venous and arterial potassium.

Conclusions

We found important and clinically relevant variability in potassium values between sampling sites. Clinical decisions should not rely on one biological indicator. However, according to our results, the site of lowest potassium, and therefore the preferred site for a single potassium sampling is central venous blood. The use of multivariable prediction tools may help to mitigate the risks inherent in the limits of potassium measurement.

Trial registration

ClinicalTrials.gov Identifier: NCT03096561.

Malignant Arrhythmias During Induction of Target Temperature Management After Cardiac Arrest

The aim of this study was to evaluate the incidence and determinants of malignant arrhythmias (MA) in patients with shock following out-of-hospital cardiac arrest (OHCA) treated with targeted temperature management. Risk factors for the development of MA were prospectively analyzed in patients after OHCA. MA were defined as ventricular tachycardia or fibrillation with a duration >30 seconds, which had to be terminated by defibrillation. All patients were treated with therapeutic hypothermia for 24 hours. Demographics, OHCA details, interventions, and intensive care unit (ICU) treatment were recorded. A total of 55 patients were included, 11 (20%) of whom developed MA during the ICU stay. All MA occurred within the first 18 hours after admission. Patients who developed MA showed a stronger decrease in body temperature (Δ -2.4°C ± 0.8°C vs. Δ -1.3°C ± 1.3°C; p = 0.016) and in serum potassium levels (Δ -0.9 ± 1 mmol/L vs. Δ -0.3 ± 0.6 mmol/L; p = 0.037) during the cooling period compared with patients without MA. In the multivariable analysis, fast temperature decline as well as lower potassium levels were associated with MA. In addition, higher number of shocks during resuscitation and higher ICU epinephrine use were independent predictors of MA in patients with OHCA. The use of epinephrine as well as hypokalemia in context with intense cooling may increase the incidence of MA in patients with shock after cardiac arrest. Therefore, these therapeutic strategies should be applied with caution in this vulnerable group of patients.

Hypothermie accidentelle

L’hypothermie accidentelle est définie comme une baisse non intentionnelle de la température centrale du corps en dessous de 35 °C. La prévention de l’hypothermie est essentielle. La mesure de la température centrale est nécessaire au diagnostic d’hypothermie et permet d’en juger la sévérité. En présence de signes de vie, et en présence d’une hypothermie pure, l’instabilité hémodynamique apparente ne devrait en principe pas faire l’objet d’une prise en charge spécifique. Un risque d’arrêt cardiaque (AC) est présent si la température chute en dessous de 30–32 °C. En raison du risque d’AC, un patient hypotherme devrait bénéficier de l’application d’un monitoring avant toute mobilisation, laquelle devra être prudente. En cas d’AC, seule la mesure de la température oesophagienne est fiable. Si l’hypothermie est suspectée comme étant potentiellement responsable de l’AC du patient, celui-ci doit être transporté sous réanimation cardiopulmonaire vers un hôpital disposant d’une méthode de réchauffement par circulation extracorporelle (CEC). La valeur de la kaliémie ainsi que les autres paramètres à disposition (âge, sexe, valeur de la température corporelle, durée du low flow, présence d’une asphyxie) permettront de décider de l’indication d’une CEC de réchauffement. Le pronostic des patients victimes d’un AC sur hypothermie est potentiellement excellent, y compris sur le plan neurologique.

Cut-off values of serum potassium and core temperature at hospital admission for extracorporeal rewarming of avalanche victims in cardiac arrest: A retrospective multi-centre study

AIM

Evidence of existing guidelines for the on-site triage of avalanche victims is limited and adherence suboptimal. This study attempted to find reliable cut-off values for the identification of hypothermic avalanche victims with reversible out-of-hospital cardiac arrest (OHCA) at hospital admission. This may enable hospitals to allocate extracorporeal life support (ECLS) resources more appropriately while increasing the proportion of survivors among rewarmed victims.

METHODS

All avalanche victims with OHCA admitted to seven centres in Europe capable of ECLS from 1995 to 2016 were included. Optimal cut-off values, for parameters identified by logistic regression, were determined by means of bootstrapping and exact binomial distribution and served to calculate sensitivity, rate of overtriage, positive and negative predictive values, and receiver operating curves.

RESULTS

In total, 103 avalanche victims with OHCA were included. Of the 103 patients 61 (58%) were rewarmed by ECLS. Six (10%) of the rewarmed patients survived whilst 55 (90%) died. We obtained optimal cut-off values of 7 mmol/L for serum potassium and 30 °C for core temperature.

CONCLUSION

For in-hospital triage of avalanche victims admitted with OHCA, serum potassium accurately predicts survival. The combination of the cut-offs 7 mmol/L for serum potassium and 30 °C for core temperature achieved the lowest overtriage rate (47%) and the highest positive predictive value (19%), with a sensitivity of 100% for survivors. The presence of vital signs at extrication is strongly associated with survival. For further optimisation of in-hospital triage, larger datasets are needed to include additional parameters.

Esophageal Heat Exchanger Versus Water-Circulating Cooling Blanket for Targeted Temperature Management

To date, the optimal cooling device for targeted temperature management (TTM) remains unclear. Water-circulating cooling blankets are broadly available and quickly applied but reveal inaccuracy during maintenance and rewarming period. Recently, esophageal heat exchangers (EHEs) have been shown to be easily inserted, revealed effective cooling rates (0.26-1.12°C/h), acceptable deviations from target core temperature (<0.5°C), and rewarming rates between 0.2 and 0.4°C/h. The aim of this study was to compare cooling rates, accuracy during maintenance, and rewarming period as well as side effects of EHEs with water-circulating cooling blankets in a porcine TTM model. Mean core temperature of domestic pigs (n = 16) weighing 83.2 ± 3.6 kg was decreased to a target core temperature of 33°C by either using EHEs or water-circulating cooling blankets. After 8 hours of maintenance, rewarming was started at a goal rate of 0.25°C/h. Mean cooling rates were 1.3 ± 0.1°C/h (EHE) and 3.2 ± 0.5°C/h (blanket, p < 0.0002). Mean difference to target core temperature during maintenance ranged between ±1°C. Mean rewarming rates were 0.21 ± 0.01°C/h (EHE) and 0.22 ± 0.02°C/h (blanket, n.s.). There were no differences with regard to side effects such as brady- or tachycardia, hypo- or hyperkalemia, hypo- or hyperglycemia, hypotension, shivering, or esophageal tissue damage. Target temperature can be achieved faster by water-circulating cooling blankets. EHEs and water-circulating cooling blankets were demonstrated to be reliable and safe cooling devices in a prolonged porcine TTM model with more variability in EHE group.

On-Site Treatment of Snow Avalanche Victims: From Bench to Mountainside

The number of avalanche accidents involving winter recreationists has notably increased in recent decades due to the increasing popularity of outdoor winter activities. The International Liaison Committee on Cardiopulmonary Resuscitation, the International Commission for Mountain Emergency Medicine (ICAR Medcom), and the Wilderness Medical Society have recently published evidenced-based recommendations for the on-site treatment of snow avalanche victims. Despite these recommendations, recent studies found poor knowledge and compliance by both healthcare providers and laypersons. The aim of this nonsystematic review is to provide an updated overview of avalanche accident epidemiology, to present recent advances in snow avalanche pathophysiology, and to discuss recent advancements in on-site treatment of snow avalanche victims.

Prognostic factors for patients with accidental hypothermia: A multi-institutional retrospective cohort study

INTRODUCTION

In cases of severe accidental hypothermia (AH) in urban areas, the prognostic factors are unknown. We identified factors associated with in-hospital mortality in patients with moderate-to-severe AH in urban areas of Japan.

METHOD

The J-Point registry database is a multi-institutional retrospective cohort study for AH in 12 Japanese emergency departments. From this registry, we enrolled patients whose core body temperature was 32 °C or less on admission. In-hospital death was the primary outcome of this study. We investigated the association between each candidate prognostic factor and in-hospital death by applying the multivariate logistic regression analyses with adjusted odds ratios (AORs) and their 95% confidence interval [CI] as the effect variables.

RESULTS

Of 572 patients registered in the J-point registry, 358 hypothermic patients were eligible for analyses. Median body temperature was 29.2 °C (interquartile range, 27.0 °C-30.8 °C). In-hospital deaths comprised 26.3% (94/358) of all study patients. Factors associated with in-hospital death were age ≥ 75 years (AOR, 3.09; 95% CI, 1.31-7.27), need for assistance with activities of daily living (ADL; AOR, 3.06; 95% CI, 1.68-5.59), hemodynamic instability (AOR, 2.49; 95% CI, 1.32-4.68), and hyperkalemia (≥5.6 mEq/L; AOR, 2.65; 95% CI, 1.13-6.21).

CONCLUSION

The independent prognostic factors associated with in-hospital mortality of patients with moderate-to-severe AH in urban areas of Japan were age ≥ 75 years, need for assistance with ADL, hemodynamic instability, and hyperkalemia.