Extracorporeal Life Support in Accidental Hypothermia with Cardiac Arrest-A Narrative Review

Eligibility for eCPR Warming in Hypothermic Cardiac Arrest: Lack of Guidelines and the Current Constraints of Artificial Intelligence in Clinical Decision-Making

AIM OF THE STUDY

Artificial intelligence (AI) such as large language models (LLMs) tools are potential sources of information on hypothermic cardiac arrest (HCA). The aim of our study was to determine whether, for patients with HCA, LLMs provide information consistent with expert consensus on criteria that would usually contraindicate extracorporeal cardiopulmonary resuscitation (eCRP) in patients with normothermic cardiac arrest (NCA), but not HCA.

METHODS

Based on Extracorporeal Life Support Organization guidelines, selected factors were identified that may be contraindications to eCPR in NCA but not in HCA. Four questions were created and entered into AI software (GPT-3.5 turbo, GPT-4o, GPT-4o-mini, Claude 3.5 Sonnet, Claude 3 Haiku, Mistral Large, Mistral Small, Gemini Pro and Gemini Flash). The responses obtained and citations returned were assessed by an international panel of experts for consistency with current knowledge.

RESULTS

Complete agreement of responses with expert consensus was obtained for 5/10 AI tools. In total, all AI tools presented 101 items in the literature. No reference was rated as "correct"; 45 citations (45%) "existed but did not answer the question"; and 56 citations (55%) were considered "hallucinatory".

CONCLUSION

Use of artificial intelligence in decision-making for extracorporeal cardiopulmonary resuscitation in patients with hypothermic cardiac arrest risks unjustifiably withdrawing treatment from patients who have a chance of survival with a good neurological outcome. Large language models should not be used as the only tool for decision-making.

Management and outcome of patients with cardiac arrest after avalanche accidents in the Swiss Alps: A retrospective analysis

Aim

Our aim is to evaluate the management and outcome of avalanche victims in cardiac arrest (CA), focusing on the adherence to international management guidelines and to identify ways to improve the future care of avalanche victims through retrospective evaluation of the missions.

Methods

We analysed a retrospective cohort of all avalanche victims in CA treated by Swiss Air-Rescue Rega between 2010 and 2024. Data regarding the avalanche burial (type of burial, burial duration, presence of a patent airway) were evaluated, as were helicopter operational data, data on prehospital medical care [cardiopulmonary resuscitation (CPR) efforts, airway management, core temperature], transport destination, data from further in-hospital treatment if applicable [core temperature, type of rewarming, serum potassium levels, extracorporeal life support (ECLS)] as well as patient outcome.

Results

147 patients could be evaluated. 50 (34%) were declared dead without CPR efforts. CPR was started in 97 patients (66%), of whom 19 achieved ROSC (13%). Only 4 of these patients survived to hospital discharge (3%), 3 of whom had a good neurological outcome (2%). 34 patients (23%) were transported to hospital while CPR was ongoing, of whom in 11 (7%) ECLS was tried to initiate. None of these patients survived to hospital discharge. 27 patients (18%) were not treated in accordance with the guidelines. 22 of these (15%) were (potentially) undertreated (mainly in the sense of transport to a non-ECLS centre, although an ECLS centre would have been correct), 5 (3%) were overtreated (mainly in the sense of transport under ongoing CPR, although not indicated). 61% were tracheally intubated. On admission, core temperature was 1.9 °C (95% confidence interval 1.1-2.7) lower than the temperature measured on scene.

Conclusions

Patients who suffer a CA in avalanche accidents have a very poor outcome. A high proportion of patients were not tracheally intubated during transport, cooled down further during resuscitation and transport or were not transported to ECLS centres although indicated. On the other hand, the outcome of ECLS patients is extremely poor.

Considering veno-venous extracorporeal membrane oxygenation as a first-line strategy for rewarming in accidental hypothermia complicated by cardiac arrest - a case series

Severe accidental hypothermia can lead to cardiac arrest. The most efficient method of resuscitating and warming is by ECMO (Extracorporeal Membrane Oxygenation). While the convention is to use VA ECMO (Veno Arterial ECMO), using VV ECMO (Veno Venous ECMO) in which the blood is returned directly into the right ventricle could be an alternative and lead to conversion to life sustaining cardiac rhythm. In this article we present our case series of ECMO for resuscitation of accidental hypothermia complicated by cardiac arrest. We used VV ECMO for 4 patients; in 3 of them ROSC (Return of Spontaneous Circulation) was successfully achieved. We also discuss the potential advantages of VV ECMO and VA ECMO in this setting and present our algorithm for management.

Methods and equipment available for prehospital treatment of accidental hypothermia: a survey of Norwegian prehospital services

BACKGROUND

Accidental hypothermia is associated with increased morbidity and mortality and poses a significant challenge for both professional and volunteer rescue services in prehospital settings. This study investigated the methods and equipment available to treat patients with cold stress or accidental hypothermia before reaching hospital in Norway.

METHODS

We surveyed 156 respondents representing 708 units from both the professional and volunteer Norwegian prehospital chain of care between 2023 and 2024. Professional services included national ground ambulances, boat ambulances, national fixed wing and helicopter air ambulance services, search and rescue helicopter services, and urban search and rescue services. Volunteer services included Norwegian People's Aid and the Norwegian Red Cross Search and Rescue Corps. The survey queried the availability of active warming equipment, passive insulation materials, thermometers for detecting hypothermia, and preferred sites for temperature measurements. The study also investigated whether there has been a development in available equipment compared to a similar study conducted in 2013.

RESULTS

The survey achieved a response rate of 70.5%. Chemical heat pads were the most frequently used type of equipment for active external warming and were the only equipment used by volunteer rescue services. All services possessed equipment for passive external warming, with duvets, space blankets and wool- or cotton blankets being the most commonly available. Thermometers for detecting hypothermia were found in 86.3% of professional rescue services and 15% of volunteer units. Almost all respondents reported consistent equipment setups year-round.

CONCLUSION

All Norwegian prehospital services, both professional and volunteer, reported having equipment available for active and passive external warming. Thermometers for detecting hypothermia were reported by all professional services. The most notable change in the equipment available to treat patients with prehospital cold stress and accidental hypothermia in Norway was the increased availability of active external rewarming equipment in 2024 compared with that in 2013.

The impact of a dedicated checklist on the quality of onsite management of critically buried avalanche victims in cardiac arrest in a Swiss helicopter emergency medical service

BACKGROUND

The management of avalanche victims in cardiac arrest (CA) is a challenging situation for rescuers. Despite existing specific management algorithms, previous studies have reported poor compliance with international guidelines and incomplete documentation and transmission of the information required for patient management. The Avalanche Victim Resuscitation Checklist (AVRC) was developed in 2014 in response by the International Commission for Mountain Emergency Medicine. Our aim was to assess the impact of the AVRC on the quality of onsite management of critically buried avalanche victims in CA, i.e. the compliance of management with international guidelines and the completeness of documentation of avalanche specific information.

METHODS

We assessed compliance and documentation in a Swiss helicopter emergency medical service (HEMS) between January 2010 and April 2020. Victims buried for more than 24 h were excluded.

RESULTS

In the 10-year study period, 87 critically buried avalanche victims in CA were treated by the HEMS, 44 of them after the introduction of the AVRC. Enough information was available to assess management compliance in over 90% of cases (n = 79). Inadequate management (n = 25, 32%) and incomplete documentation occurred more often in patients with a long burial duration. After the introduction of the AVRC, the compliance of patient management with the guidelines increased by 36% (from 59 to 95%, p < 0.05) and led to complete documentation of the required information for patient management.

CONCLUSIONS

The use of the AVRC improves the quality of management of critically buried avalanche victims in CA and ensures complete documentation of avalanche specific information. Quality improvement efforts should focus on the management of avalanche victims with a long burial duration. The use of the AVRC enables identification and appropriate treatment of patients with hypothermic cardiac arrest.

Outcomes of extracorporeal life support in hypothermic cardiac arrest: Revisiting ELSO guidelines

AIM OF THE STUDY

Predictive factors for poor outcomes in hypothermic cardiac arrest (HCA) differ from those in normothermic out-of-hospital cardiac arrest (OHCA). This study aimed to evaluate the outcomes of extracorporeal life support (ECLS) in HCA patients who may not be considered eligible based on the guidelines set by the Extracorporeal Life Support Organization (ELSO).

METHODS

A retrospective multicentre study included 127 HCA patients, divided into two groups: those meeting the ELSO eligibility criteria for ECLS, and those with at least one of the following ELSO exclusion criteria: age over 70 years, unwitnessed cardiac arrest, or asystole.

RESULTS

Among the 62 patients who met the ELSO criteria, 38 (61 %) survived to hospital discharge, with 34 (89 %) achieving a favourable neurological outcomes. Of the 65 patients who received ECLS despite not meeting ELSO criteria, 24 (37 %) survived to discharge, with 20 (83 %) demonstrating a favourable neurological outcomes. In patients not meeting one or two ELSO criteria, survival rates were 18 of 47 (38 %) and 6 of 16 (38 %) respectively, with 83 % of survivors in both groups achieving favourable neurological outcomes. The two patients who failed to meet all three ELSO criteria did not survive.

CONCLUSION

Qualification of patients with hypothermic cardiac arrest for ECLS rewarming should not be strictly based on guidelines for normothermic cardiac arrest, as this may result in not initiating potentially life-saving treatment for patients who could have favourable prognoses for survival with good neurological outcomes.

Echocardiography in Cardiac Arrest: Incremental Diagnostic and Prognostic Role during Resuscitation Care

BACKGROUND

Cardiac arrest (CA) is a life-critical condition. Patients who survive after CA go into a defined post-cardiac arrest syndrome (PCAS). In this clinical context, the role of the echocardiogram in recent years has become increasingly important to assess the causes of arrest, the prognosis, and any direct and indirect complications dependent on cardiopulmonary resuscitation (CPR) maneu-vers.

METHODS

We have conduct a narrative revision of literature.

RESULTS

The aim of our review is to evaluate the increasingly important role of the transthoracic and transesophageal echocardiogram in the CA phase and especially post-arrest, analyzing the data already present in the literature.

CONCLUSION

Transthoracic and transesophageal echocardiogram in the CA phase take on important diagnostic and prognostic role.

Position statement of the Brazilian Palliative Care Academy on withdrawing and withholding life-sustaining interventions in the context of palliative care

The issue of withrawing and withholding life-sustaining interventions is an important source of controversy among healthcare professionals caring for patients with serious illnesses. Misguided decisions, both in terms of the introduction/maintenance and the withdrawal/withholding of these measures, represent a source of avoidable suffering for patients, their loved ones, and healthcare professionals. This document represents the position statement of the Bioethics Committee of the Brazilian Palliative Care Academy on this issue and establishes seven principles to guide, from a bioethical perspective, the approach to situations related to this topic in the context of palliative care in Brazil. The position statement establishes the equivalence between the withdrawal and withholding of life-sustaining interventions and the inadequacy related to initiating or maintaining such measures in contexts where they are in disagreement with the values and care goals defined together with patients and their families. Additionally, the position statement distinguishes strictly futile treatments from potentially inappropriate treatments and elucidates their critical implications for the appropriateness of the medical decision-making process in this context. Finally, we address the issue of conscientious objection and its limits, determine that the ethical commitment to the relief of suffering should not be influenced by the decision to employ or not employ life-sustaining interventions and warn against the use of language that causes patients/families to believe that only one of the available options related to the use or nonuse of these interventions will enable the relief of suffering.

Impact of extracorporeal cardiopulmonary resuscitation on neurological prognosis and survival in adult patients after cardiac arrest: An individual pooled patient data meta-analysis

BACKGROUND

We aimed to estimate the effect of extracorporeal cardiopulmonary resuscitation (ECPR) on neurological outcome and mortality, when compared to conventional cardiopulmonary resuscitation (CCPR), using an individual patient data meta-analysis (IPDMA).

METHODS

A systematic literature search was performed up to the 20th of October 2022 in the PubMed, EMBASE and CENTRAL databases. For observational studies with unmatched populations, a propensity score including age, location of arrest and initial rhythm was used to match ECPR and CCPR patients in a 1:1 ratio. The primary and secondary outcomes were unfavorable neurological outcome (Cerebral Performance Category of 3-5) and mortality, respectively, which were both collected at different time-points.

RESULTS

Data from 17 studies, including 2064 matched cardiac arrest (CA) patients (1031 ECPR and 1033 CCPR cases) were included. In comparison to CCPR, ECPR was associated with a decreased odds of unfavorable neurological outcome (847, 82.2% vs. 897, 86.8% - OR 0.68 [95%CI 0.53-0.87]; p = 0.002) and death (803, 77.9% vs. 860, 83.3% - OR 0.68 [95%CI 0.54-0.86]; p = 0.001). These results were consistent across most of the prespecified subgroups. Moreover, the odds of both unfavorable neurological outcome and mortality were significantly influenced by initial rhythm, cause of arrest and combinations of lactate levels on admission and duration of resuscitation.

CONCLUSIONS

This IPDMA showed that ECPR was associated with significantly lower rates of unfavorable neurological outcome and mortality in refractory CA. The overall effect could be influenced by CA characteristics and the severity of the initial injury.

CT Imaging Before Extracorporeal Cardiopulmonary Resuscitation in Hypothermic Cardiac Arrest With Trauma

Hypothermic cardiac arrest (HCA) with concomitant trauma presents a significant clinical management challenge. In these case reports, computed tomography (CT) imaging was performed before extracorporeal cardiopulmonary resuscitation (ECPR) in patients with cardiac arrest, accidental hypothermia, and trauma. The first case involved a 74-year-old male who collapsed outside his home under freezing conditions. Upon arrival at the emergency department (ED), he was in cardiac arrest with a core body temperature of 25.0°C and suspected head trauma. CT imaging revealed minor traumatic brain injuries and bilateral femoral fractures. ECPR was initiated after CT imaging, which led to successful rewarming and full neurological recovery. The second case describes a 32-year-old female who jumped from a bridge, experienced cardiac arrest during the rescue, and had a core temperature of 17.4°C. CT imaging before ECPR revealed no significant trauma. Despite prolonged resuscitation, the patient showed a complete neurological recovery. CT imaging before ECPR allows appropriate patient selection by ruling out cardiac arrest before hypothermia and major hemorrhagic complications. Hypothermic cardiac arrest may be acceptable for prolonged resuscitation time on CT imaging owing to reduced cerebral metabolism. These rare case reports demonstrate the potential benefits of CT imaging before ECPR in the management of hypothermic cardiac arrest with trauma and aid in appropriate candidate selection and effective intervention without compromising neurological outcomes.

Etiology-Based Prognosis of Extracorporeal CPR Recipients After Out-of-Hospital Cardiac Arrest: A Retrospective Multicenter Cohort Study

BACKGROUND

A better understanding of the relative contributions of various factors to patient outcomes is essential for optimal patient selection for extracorporeal CPR (ECPR) therapy for patients with out-of-hospital cardiac arrest (OHCA). However, evidence on the prognostic comparison based on the etiologies of cardiac arrest is limited.

RESEARCH QUESTION

What is the etiology-based prognosis of patients undergoing ECPR for OHCA?

STUDY DESIGN AND METHODS

This retrospective multicenter registry study involved 36 institutions in Japan and included all adult patients with OHCA who underwent ECPR between January 2013 and December 2018. The primary etiology for OHCA was determined retrospectively from all hospital-based data at each institution. We performed a multivariable logistic regression model to determine the association between etiology of cardiac arrest and two outcomes: favorable neurologic outcome and survival at hospital discharge.

RESULTS

We identified 1,781 eligible patients, of whom 1,405 (78.9%) had cardiac arrest because of cardiac causes. Multivariable logistic regression analysis for favorable neurologic outcome showed that accidental hypothermia (adjusted OR, 5.12; 95% CI, 2.98-8.80; P < .001) was associated with a significantly higher rate of favorable neurologic outcome than cardiac causes. Multivariable logistic regression analysis for survival showed that accidental hypothermia (adjusted OR, 5.19; 95% CI, 3.15-8.56; P < .001) had significantly higher rates of survival than cardiac causes. Acute aortic dissection/aneurysm (adjusted OR, 0.07; 95% CI, 0.02-0.28; P < .001) and primary cerebral disorders (adjusted OR, 0.12; 95% CI, 0.03-0.50; P = .004) had significantly lower rates of survival than cardiac causes.

INTERPRETATION

In this retrospective multicenter cohort study, although most patients with OHCA underwent ECPR for cardiac causes, accidental hypothermia was associated with favorable neurologic outcome and survival; in contrast, acute aortic dissection/aneurysm and primary cerebral disorders were associated with nonsurvival compared with cardiac causes.

Wilderness Medical Society Clinical Practice Guidelines for Prevention and Management of Avalanche and Nonavalanche Snow Burial Accidents: 2024 Update

To provide guidance to the general public, clinicians, and avalanche professionals about best practices, the Wilderness Medical Society convened an expert panel to revise the evidence-based guidelines for the prevention, rescue, and resuscitation of avalanche and nonavalanche snow burial victims. The original panel authored the Wilderness Medical Society Practice Guidelines for Prevention and Management of Avalanche and Nonavalanche Snow Burial Accidents in 2017. A second panel was convened to update these guidelines and make recommendations based on quality of supporting evidence.

Termination of Cardiopulmonary Resuscitation in Mountain Rescue: A Scoping Review and ICAR MedCom 2023 Recommendations

Lugnet, Viktor, Miles McDonough, Les Gordon, Mercedes Galindez, Nicolas Mena Reyes, Alison Sheets, Ken Zafren, and Peter Paal. Termination of cardiopulmonary resuscitation in mountain rescue: a scoping review and ICAR MedCom 2023 recommendations. High Alt Med Biol. 24:274-286, 2023. Background: In 2012, the International Commission for Mountain Emergency Medicine (ICAR MedCom) published recommendations for termination of cardiopulmonary resuscitation (CPR) in mountain rescue. New developments have necessitated an update. This is the 2023 update for termination of CPR in mountain rescue. Methods: For this scoping review, we searched the PubMed and Cochrane libraries, updated the recommendations, and obtained consensus approval within the writing group and the ICAR MedCom. Results: We screened a total of 9,102 articles, of which 120 articles met the inclusion criteria. We developed 17 recommendations graded according to the strength of recommendation and level of evidence. Conclusions: Most of the recommendations from 2012 are still valid. We made minor changes regarding the safety of rescuers and responses to primary or traumatic cardiac arrest. The criteria for termination of CPR remain unchanged. The principal changes include updated recommendations for mechanical chest compression, point of care ultrasound (POCUS), extracorporeal life support (ECLS) for hypothermia, the effects of water temperature in drowning, and the use of burial times in avalanche rescue.

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.

Extracorporeal cardiopulmonary resuscitation for hypothermic refractory cardiac arrests in urban areas with temperate climates

BACKGROUND

Accidental hypothermia designates an unintentional drop in body temperature below 35 °C. There is a major risk of ventricular fibrillation below 28 °C and cardiac arrest is almost inevitable below 24 °C. In such cases, conventional cardiopulmonary resuscitation is often inefficient. In urban areas with temperate climates, characterized by mild year-round temperatures, the outcome of patients with refractory hypothermic out-of-hospital cardiac arrest (OHCA) treated with extracorporeal cardiopulmonary resuscitation (ECPR) remains uncertain.

METHODS

We conducted a retrospective monocentric observational study involving patients admitted to a university hospital in Paris, France. We reviewed patients admitted between January 1, 2011 and April 30, 2022. The primary outcome was survival at 28 days with good neurological outcomes, defined as Cerebral Performance Category 1 or 2. We performed a subgroup analysis distinguishing hypothermic refractory OHCA as either asphyxic or non-asphyxic.

RESULTS

A total of 36 patients were analysed, 15 of whom (42%) survived at 28 days, including 13 (36%) with good neurological outcomes. Within the asphyxic subgroup, only 1 (10%) patient survived at 28 days, with poor neurological outcomes. A low-flow time of less than 60 min was not significantly associated with good neurological outcomes (P = 0.25). Prehospital ECPR demonstrated no statistically significant difference in terms of survival with good neurological outcomes compared with inhospital ECPR (P = 0.55). Among patients treated with inhospital ECPR, the HOPE score predicted a 30% survival rate and the observed survival was 6/19 (32%).

CONCLUSION

Hypothermic refractory OHCA occurred even in urban areas with temperate climates, and survival with good neurological outcomes at 28 days stood at 36% for all patients treated with ECPR. We found no survivors with good neurological outcomes at 28 days in submersed patients.

The Role of Extracorporeal Membrane Oxygenation ECMO in Accidental Hypothermia and Rewarming in Out-of-Hospital Cardiac Arrest Patients-A Literature Review

Accidental hypothermia, defined as an unintentional drop of the body core temperature below 35 °C, is one of the causes of cardiocirculatory instability and reversible cardiac arrest. Currently, extracorporeal life support (ECLS) rewarming is recommended as a first-line treatment for hypothermic cardiac arrest patients. The aim of the ECLS rewarming is not only rapid normalization of core temperature but also maintenance of adequate organ perfusion. Veno-arterial extracorporeal membrane oxygenation (ECMO) is a preferred technique due to its lower anticoagulation requirements and potential to prolong circulatory support. Although highly efficient, ECMO is acknowledged as an invasive treatment option, requiring experienced medical personnel and is associated with the risk of serious complications. In this review, we aimed to discuss the clinical aspects of ECMO management in severely hypothermic cardiac arrest patients.

Hypothermic cardiac arrest patients admitted to hospital who were not rewarmed with extracorporeal life support: A retrospective study

Aims

Our goal was to study hypothermic cardiac arrest (CA) patients who were not rewarmed by Extracorporeal Life Support (ECLS) but were admitted to a hospital equipped for it. The focus was on whether the decisions of non-rewarming, meaning termination of resuscitation, were compliant with international guidelines based on serum potassium at hospital admission.

Methods

We retrospectively included all hypothermic CA who were not rewarmed, from three Swiss centers between 1st January 2000 and 2nd May 2021. Data were extracted from medical charts and assembled into two groups for analysis according to serum potassium. We identified the criteria used to terminate resuscitation. We also retrospectively calculated the HOPE score, a multivariable tool predicting the survival probability in hypothermic CA undergoing ECLS rewarming.

Results

Thirty-eight victims were included in the study. The decision of non-rewarming was compliant with international guidelines for 12 (33%) patients. Among the 36 patients for whom the serum potassium was measured at hospital admission, 24 (67%) had a value that - alone - would have indicated ECLS. For 13 of these 24 (54%) patients, the HOPE score was <10%, meaning that ECLS was not indicated. The HOPE estimation of the survival probabilities, when used with a 10% threshold, supported 23 (68%) of the non-rewarming decisions made by the clinicians.

Conclusions

This study showed a low adherence to international guidelines for hypothermic CA patients. In contrast, most of these non-rewarming decisions made by clinicians would have been compliant with current guidelines based on the HOPE score.

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.

The Beginning of an ECLS Center: First Successful ECPR in an Emergency Department in Romania-Case-Based Review

According to the latest international resuscitation guidelines, extracorporeal cardiopulmonary resuscitation (ECPR) involves the utilization of extracorporeal membrane oxygenation (ECMO) in specific patients experiencing cardiac arrest, and it can be considered in situations where standard cardiopulmonary resuscitation efforts fail if they have a potentially reversible underlying cause, among which we can also find hypothermia. In cases of cardiac arrest, both witnessed and unwitnessed, hypothermic patients have higher chances of survival and favorable neurological outcomes compared to normothermic patients. ECPR is a multifaceted procedure that requires a proficient team, specialized equipment, and comprehensive multidisciplinary support within a healthcare system. However, it also carries the risk of severe, life-threatening complications. With the increasing use of ECPR in recent years and the growing number of centers implementing this technique outside the intensive care units, significant uncertainties persist in both prehospital and emergency department (ED) settings. Proper organization is crucial for an ECPR program in emergency settings, especially given the challenges and complexities of these treatments, which were previously not commonly used in ED. Therefore, within a narrative review, we have incorporated the initial case of ECPR in an ED in Romania, featuring a successful resuscitation in the context of severe hypothermia (20 °C) and a favorable neurological outcome (CPC score of 1).

On-site treatment of avalanche victims: Scoping review and 2023 recommendations of the international commission for mountain emergency medicine (ICAR MedCom)

INTRODUCTION

The International Commission for Mountain Emergency Medicine (ICAR MedCom) developed updated recommendations for the management of avalanche victims.

METHODS

ICAR MedCom created Population Intervention Comparator Outcome (PICO) questions and conducted a scoping review of the literature. We evaluated and graded the evidence using the American College of Chest Physicians system.

RESULTS

We included 120 studies including original data in the qualitative synthesis. There were 45 retrospective studies (38%), 44 case reports or case series (37%), and 18 prospective studies on volunteers (15%). The main cause of death from avalanche burial was asphyxia (range of all studies 65-100%). Trauma was the second most common cause of death (5-29%). Hypothermia accounted for few deaths (0-4%).

CONCLUSIONS AND RECOMMENDATIONS

For a victim with a burial time ≤ 60 minutes without signs of life, presume asphyxia and provide rescue breaths as soon as possible, regardless of airway patency. For a victim with a burial time > 60 minutes, no signs of life but a patent airway or airway with unknown patency, presume that a primary hypothermic CA has occurred and initiate cardiopulmonary resuscitation (CPR) unless temperature can be measured to rule out hypothermic cardiac arrest. For a victim buried > 60 minutes without signs of life and with an obstructed airway, if core temperature cannot be measured, rescuers can presume asphyxia-induced CA, and should not initiate CPR. If core temperature can be measured, for a victim without signs of life, with a patent airway, and with a core temperature < 30 °C attempt resuscitation, regardless of burial duration.

Extracorporeal membrane oxygenation versus conventional rewarming for severe hypothermia in an urban emergency department

BACKGROUND

Severe hypothermia (core body temperature < 28°C) is life-threatening and predisposes to cardiac arrest. The comparative effectiveness of different active internal rewarming methods in an urban U.S. population is unknown. We aim to compare outcomes between hypothermic emergency department (ED) patients rewarmed conventionally using an intravascular rewarming catheter or warm fluid lavage versus those rewarmed using extracorporeal membrane oxygenation (ECMO).

METHODS

We performed a retrospective cohort analysis of adults with severe hypothermia due to outdoor exposure presenting to an urban ED in Minnesota, 2007-2021. The primary outcome was hospital survival. We also calculated the rewarming rate in the 4 h after ED arrival and compared these data between patients rewarmed with ECMO (the extracorporeal rewarming group) versus without ECMO (the conventional rewarming group). We repeated these analyses in the subgroup of patients with cardiac arrest.

RESULTS

We analyzed 44 hypothermic ED patients: 25 patients in the extracorporeal rewarming group (median temperature 24.1°C, 84% with cardiac arrest) and 19 patients in the conventional rewarming group (median temperature 26.3°C, 37% with cardiac arrest; 89% received an intravascular rewarming catheter). The median rewarming rate was greater in the extracorporeal versus conventional group (2.3°C/h vs. 1.5°C/h, absolute difference 0.8°C/h, 95% confidence interval [CI] 0.3-1.2°C/h) yet hospital survival was similar (68% vs. 74%). Among patients with cardiac arrest, hospital survival was greater in the extracorporeal versus conventional group (71% vs. 29%, absolute difference 42%, 95% CI 4%-82%).

CONCLUSIONS

Among ED patients with severe hypothermia and cardiac arrest, survival was significantly higher with ECMO versus conventional rewarming. Among all hypothermic patients, ECMO use was associated with faster rewarming than conventional methods.

Outcome of extracorporeal membrane oxygenation use in severe accidental hypothermia with cardiac arrest and circulatory instability: A multicentre, prospective, observational study in Japan (ICE-CRASH study)

AIM

To elucidate the effectiveness of extracorporeal membrane oxygenation (ECMO) in accidental hypothermia (AH) patients with and without cardiac arrest (CA), including details of complications.

METHODS

This study was a multicentre, prospective, observational study of AH in Japan. All adult (aged ≥18 years) AH patients with body temperature ≤32 °C who presented to the emergency department between December 2019 and March 2022 were included. Among the patients, those with CA or circulatory instability, defined as severe AH, were selected and divided into the ECMO and non-ECMO groups. We compared 28-day survival and favourable neurological outcomes at discharge between the ECMO and non-ECMO groups by adjusting for the patients' background characteristics using multivariable logistic regression analysis.

RESULTS

Among the 499 patients in this study, 242 patients with severe AH were included in the analysis: 41 in the ECMO group and 201 in the non-ECMO group. Multivariable analysis showed that the ECMO group was significantly associated with better 28-day survival and favourable neurological outcomes at discharge in patients with CA compared to the non-ECMO group (odds ratio [OR] 0.17, 95% confidence interval [CI]: 0.05-0.58, and OR 0.22, 95%CI: 0.06-0.81). However, in patients without CA, ECMO not only did not improve 28-day survival and neurological outcomes, but also decreased the number of event-free days (ICU-, ventilator-, and catecholamine administration-free days) and increased the frequency of bleeding complications.

CONCLUSIONS

ECMO improved survival and neurological outcomes in AH patients with CA, but not in AH patients without CA.

Successful Nonextracorporeal Life Support Resuscitation and Rewarming of a Patient with Hypothermia in Cardiac Arrest

We report full recovery of a patient with hypothermia in cardiac arrest following continuous and prolonged cardiopulmonary resuscitation (CPR) and conventional, nonextracorporeal life support (non-ECLS) methods. A 57-y-old man presented with unwitnessed cardiac arrest and a core temperature of 23°C (73°F). The presenting cardiac rhythm was ventricular fibrillation. The team administered epinephrine and performed defibrillation and CPR. Because ECLS was unavailable at the facility, the medical team externally and internally rewarmed the patient using heated blankets, forced warmed air, thoracic lavage, and warmed IV fluids. The patient achieved return of spontaneous circulation after 4 h 56 min of continuous CPR and rewarming. The medical team admitted the patient to the intensive care unit. He achieved full neurologic recovery the following day. When ECLS is not available and transfer is not appropriate because of patient instability or hospital location, conventional rewarming methods and continuous, prolonged CPR can lead to successful outcomes in patients with hypothermia in cardiac arrest. This case demonstrates that CPR in patients with hypothermia-associated cardiac arrest can lead to full recovery.

Prevention of Hypothermia in the Aftermath of Natural Disasters in Areas at Risk of Avalanches, Earthquakes, Tsunamis and Floods

Throughout history, accidental hypothermia has accompanied natural disasters in cold, temperate, and even subtropical regions. We conducted a non-systematic review of the causes and means of preventing accidental hypothermia after natural disasters caused by avalanches, earthquakes, tsunamis, and floods. Before a disaster occurs, preventive measures are required, such as accurate disaster risk analysis for given areas, hazard mapping and warning, protecting existing structures within hazard zones to the greatest extent possible, building structures outside hazard zones, and organising rapid and effective rescue. After the event, post hoc analyses of failures, and implementation of corrective actions will reduce the risk of accidental hypothermia in future disasters.

Accidental Hypothermia: 2021 Update

Accidental hypothermia is an unintentional drop of core temperature below 35 °C. Annually, thousands die of primary hypothermia and an unknown number die of secondary hypothermia worldwide. Hypothermia can be expected in emergency patients in the prehospital phase. Injured and intoxicated patients cool quickly even in subtropical regions. Preventive measures are important to avoid hypothermia or cooling in ill or injured patients. Diagnosis and assessment of the risk of cardiac arrest are based on clinical signs and core temperature measurement when available. Hypothermic patients with risk factors for imminent cardiac arrest (temperature < 30 °C in young and healthy patients and <32 °C in elderly persons, or patients with multiple comorbidities), ventricular dysrhythmias, or systolic blood pressure < 90 mmHg) and hypothermic patients who are already in cardiac arrest, should be transferred directly to an extracorporeal life support (ECLS) centre. If a hypothermic patient arrests, continuous cardiopulmonary resuscitation (CPR) should be performed. In hypothermic patients, the chances of survival and good neurological outcome are higher than for normothermic patients for witnessed, unwitnessed and asystolic cardiac arrest. Mechanical CPR devices should be used for prolonged rescue, if available. In severely hypothermic patients in cardiac arrest, if continuous or mechanical CPR is not possible, intermittent CPR should be used. Rewarming can be accomplished by passive and active techniques. Most often, passive and active external techniques are used. Only in patients with refractory hypothermia or cardiac arrest are internal rewarming techniques required. ECLS rewarming should be performed with extracorporeal membrane oxygenation (ECMO). A post-resuscitation care bundle should complement treatment.