2025+ELSO指南：ECMO在意外性低体温症中的应用

Background

Accidental hypothermia(AH) can be caused by exposure to cold weather conditions, immersion in water, avalanche burial in snow, or indoors, mostly affecting elderly patients with multiple comorbidities.1.2 There are three stages of AH.3 In mild AH core temperatures are 35°C-32°C(95°F-89.6°F) and mental status is normal or mildly impaired. In moderate AH with core temperatures between 32°C-28°C(89.6°F-82.4°F),patients may be unconscious or conscious with altered mental

From the *Department of Anaesthesiology, Hopital Rivera-Chablais, Rennaz, Switzerland;+Air Zermatt, Zermatt/Raron/Pampel, Switzerland;#Department of Respiratory Medicine,Paracelsus Medical University, Nuremberg, Germany; SDepartment of Cardiothoracic Anaesthesiology 4142, Copenhagen University Hospital (Righospitaetlop), Copenhagen, Denmark; Institute of Mountain Emergency Medicine, Eurac Research, Bolzano; Italy;||Department of Emergency Medicine, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland; #Department of Emergency Medicine, University of Utah Health Health Director, Wilderness Medicine Fellowship Medical Director, Park City Fire EMS, Flight Physician&Associate Medical Director, AirMedt; University of Colorado School of Medicine, Aurora, Colorado; #Department of Cardiovascular Medicine and Mountain Medicine, Research, and Survey Division,Sapporo Kojinkai Memorial Hospital, Sapporo, Japan; #Department of Anaesthesia University of Cardioorthacic Anaesthesia, University Hospitals Morecambe Bay Trust, Royal Lancaster Infirmary, Lancaster, United Kingdom; 1|4|r Em University of Geneva, Geneva, Switzerland;||II Division of Cardiothoracic Surgery, Department of Surgery, University of Colorado; ##Heart Center Istituto Mediterranean per i Triapiant Ee apie de Alta Specializzazione-IRCCS ISMETT; ***Department of Emergency Medicine, Stanford University Medical Center, Palo Alto, California;++Department of Anaesthesiology and Intensive Care Medicine,St. John of God Hospital, Paracelsus Medical University, Salzburg,

Austria;##Intensive Care Unit, Geneva University Hospitals, Geneva,Switzerland; S$Department of Emergency Medicine, Jan Kochanowski University, Kieice, Poland; 1Department of Anesthesia and Intensive Care, Istituto Mediterranean per i Trapiantie Eaperia and Alta Specializazione-IRCCS ISMETT; IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII

Submitted for consideration July 2025; accepted for publication in revised form August 2025.

E.C.and J.S. contributed equally to this work.

Disclosure: The authors have no conflicts of interest to report.

Correspondence: Evelien Cools, Department of Anaesthesiology,Hopital Riviera-Chablais, Rennaz, Switzerland. Email: evelien.cools@hopitalriverachablais.chwitter:@elsoorg

Copyright© 2025 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the ASAIO. This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivative Services License 4.0(CBBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.

DOI:10.1097/MAT.00000000002557

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Take-home messages

1. There are significant differences between hypothermic and normothermic cardiac arrest.

2. Patients with out-of-hospital hypothermic cardiac arrest have better survival with more favorable neu-rological outcomes than patients with normothermic out-of-hospital cardiac arrest.

3. Extracorporeal life support (ECLS) criteria established for normothermic patients should not be used for hypothermic patients.

4. Unwitnessed cardiac arrest, asystole, long no-flow and low-flow (cardiopulmonary resuscitation [CPR]) times,age ≥70, and low EtCO2 are not contraindications to ECLS for hypothermic cardiac arrest patients.

5. ECLS rewarming produces satisfactory results in patients in severe hypothermia.

status. In severe AH with core temperatures $<28^{\circ} C\left(82.4^{\circ} F\right)$ ,patients are unconscious. Pathophysiologic changes caused by hypothermia affect the cardiovascular system, leading to dys-rhythmias, impaired cardiac output, and cardiac arrest(CA).4-7 There may be significant morbidity and mortality but there may also be favorable outcomes.8-11 Patients with core temperatures$<28^{\circ} C\left(82.4^{\circ} F\right)$ without CA can be rewarmed by conventional rewarming methods. In unstable patients, extracorporeal life support (ECLS)-extracorporeal membrane oxygenation(ECM) or cardiopulmonary bypass-is more effective than conventional means because it provides cardiorespiratory sup-port in addition to rewarming.3,8,12-17 Extracorporeal membrane oxygenation can also be used to provide post-rewarming car-diorespiratory support if necessary.

Patient selection, outcome prediction, and treatment depend on logistics and planning, including planning for the imple-mentation of ECLS.18,19 The risk of CA is high in young, healthy patients with core temperatures<28°C(82.4°C), and in elderly patients or patients of any age with comorbidities and core tem-peratures<30℃(86°F). These patients should be transferred

to centers capable of providing ECLS.20 The ICE-CRASH study showed that treatment with ECMO was significantly associ-ated with improved 28 day survival and favorable neurological outcomes at hospital discharge in patients with CA compared with those who did not receive ECMO(odds ratio[OR]: 0.17,95% confidence interval[CI]: 0.05-0.58, and OR: 0.22, 95%Cl: 0.06-0.81).21 Indications for ECLS rewiring in severely hypothermic patients with preserved circulation have not been precisely established, and the data on outcomes are conflicting.In one study, ECMO did not improve survival or neurological outcomes and increased treatment duration and frequency of bleeding complications.21 Two other studies found that patients with severe hypothermia and cardiovascular instability might benefit from extracorporeal rewarming without an increased risk of complications. The survival rate was higher in patients rewarmed with ECLS. The relative risk of death was twice as high in patients rewarmed by less invasive means.22 Eligibility for ECLS should not be based on core temperature alone or on the stage of hypothermia but also on the condition of the patient.

This expert consensus Extracorporeal Life Support Organization(ELSO) guideline gives recommendations for the use of ECLS for cardiorespiratory support and for rewarming in severe AH.

Preparation and Organization

The chain of survival in AH starts in the prehospital phase(Figure 1).12,16,23-31 Patients, who are unconscious, have a sys-tolic blood pressure of<90mm Hg, bradycardia of<40/min, or ventricular arrhythmias are at a high risk of CA.12,20,25 Cardiac arrest may be triggered by movement of the patient, by airway management, and by other rescue procedures. The onset of hypothermic cardiac arrest(HCA) reduces survival by half.26 Cautious patient movement may prevent HCA. Early recogni-tion of AH as a possible cause of CA, and provision of high-quality cardiopulmonary resuscitation(CPR) are essential to improve the chance of survival. Mechanical chest compression is advantageous because CPR may be prolonged.27 Delayed or intermittent CPR is an option in awkward or hazardous loca-tions, when moving a patient in HCA, or if insufficient rescuers

Hypothermia chain of survival

No one is dead until warm and dead

Post-rewarming care

Prehospital assessment&management.Confirm potential suitability with ECMO co-ordinator.

In-hospital assessment

Rewarming. ECMO if indicated.

ECMO if indicated.

References

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are available to perform continuous CPR. ${ }^{28}$ Long duration of transport with ongoing CPR should not be a reason to withhold resuscitation.

The receiving hospital should be notified by the emergency medical service (EMS) in collaboration with the ECLS center while the patient is still at the scene. The ECLS center should be available 24/7 to support prehospital teams.27,29 The prehos-pital hypothermia, chain of survival illustrates the importance of early recognition of AH with prevention of further cooling,with monitoring, and with transport to the correct hospital for a patient in AH (Table 1).16,23-32 Early identification of patients in the prehospital phase may be impaired by lack of core tem-perature thermometers.33-35

The ELSO provides a directory of ECLS centers worldwide(https://www.els.org/membership/centerdirectory.aspx). Each EMS agency should establish a working relationship with its local ECLS center before the first actual transfer.

Patient Selection and Qualification for ECLS

Indications for ECLS rewarming in severe AH include HCA or hemodynamic instability to prevent subsequent CA.12,25,36

Hypothermic cardiac arrest

Extracorporeal support life support is indicated in patients with HCA, core temperatures<30°C(86°F), and estimated probability of survival $\geq 10\%$ , based on the Hypothermia Outcome Prediction after ECLS (HOPE) score(Figure 2).8,16,27,31,32,36 The HOPE score estimates the survival probability after ECLS support for patients with CA from AH.8 An online calculator of the HOPE score is available at www.hypothermiascore.org. ${ }^{8}$

If the patient is considered a candidate for ECLS, CPR should be continued until ECLS is established. Core temperature should be measured using an esophageal probe(Figure 3). 8,16,31 Use caution when obtaining a potassium measurement from the femoral vessels as a hematoma(related to the coagulopa-thy) may complicate ECMO cannulation. Therefore, punc-ture of the femoral vessels should be ultrasound-guided.Unwitnessed HCA, asystole, long no-flow and low-flow times,age≥70, and low end tidal carbon dioxide $\left(EtCO_{2}\right)$ are not contraindications to ECLS for HCA (Figure 2). 8,16,36 There are significant differences between hypothemric and normother-mic CA. Extracorporeal support life support criteria established for normothermic patients should not be used for hypothermic patients. ${}^{37}$

Hypothermic Patients With Preserved Spontaneous Circulation

Indications for ECLS rewarming in severely hypothermic patients with preserved spontaneous circulation have not been precisely established, but hypotension<90mm Hg or the pres-ence of a ventricular arrhythmia typically determines if there is hemodynamic instability when deciding if a patient quali-fies for ECLS. Victims of AH with hemodynamic instability may benefit from extracorporeal rewarming compared with less invasive methods.22,30

In patients in HCA, ECLS cannulation and rewarming should not be delayed for computed tomography(CT) scanning. If there are signs of trauma, consider ECLS rewarming with mini-mal or no anticoagulation. Once stable circulation has been

achieved with venoarterial(VA) ECMO, patients with possible trauma may undergo CT scanning to assess injuries. In patients with preserved circulation and core temperature below $30^{\circ} C$ ,the decision to perform CT should be very carefully weighed against the benefits of imaging and the potential risk of CA-especially in the group of hemodynamically unstable patients who are candidates for ECLS.

ECLS Mode and Technical Considerations

Cardiopulmonary bypass (CPB) or VA ECMO may be used for rewarming depending on the immediate availability. However,VA ECMO needs fewer resources, is smaller, mobile, requires less heparin and is suitable for prolonged cardiorespiratory support in case of cardiopulmonary complications and may have superior outcomes.1,7,17,26,30 It is reasonable to use CPB if ECMO is not available, especially in multicausality incidents with severe hypothermia. Extracorporeal treatment of patients with severe hypothermia serves not only to achieve normo-thermia but also to stabilize the cardiovascular and respiratory systems and to compensate for metabolic disorders. The pre-ferred system is femor-phemoral VA ECMO with a distal perfu-sion cannula.

Vascular cannulation can be difficult because of the effects of low temperature on the vessels and surrounding tissues.The femoro-femoral configuration (arterial/venous) can rap-idly be established without interrupting CPR and is the pre-ferred configuration for establishing emergency access in adults, adolescents, and children >20kg. Smaller children and babies are best cannulated by surgical cutdown on the right neck vessels. ${ }^{4,11}$ Operators should consider the high risk of bleeding caused by hypothermia-associated coagulopathy and should choose the less invasive, percutaneous method of cannulation when feasible. Cannulation should be performed with ultrasound guidance. To maintain safety at key moments,such as puncture of the vessel, introduction of the guidewire and cannula, it is reasonable to interrupt CPR for a short time.Otherwise, interruptions in CPR should be kept to a minimum.Because of difficulties in obtaining blood for laboratory testing in hypothermic patients, it may be advisable to collect blood during cannulation to determine critical laboratory parameters.

Strictility of the operative field during cannulation is critical to prevent bloodstream infections. Cannulas should be positioned under fluoroscopic control or transesophageal echocardiography. Hypothermia increases the echogenicity of blood. In cardiac images, normal blood in the atria or ven-tricles may resemble blood clots.

Venting of the left ventricle is rarely necessary, as the heart usu-ally starts ejecting after rewarming and oxygenation. However,venting should be considered following usual criteria and ECLS practice if left ventricle(LV) distention persists or if left atrial or pulmonary congestion suppresses. Bilateral femoral cannulation is associated with reduced risk of compartment syndrome, bleed-ing, need for fasciotomy or vessel repair during ECLS, and lower in-hospital mortality compared with other configurations. ${}^{38}$

Patient and Circuit Management During ECLS

Defibrillation pads should be applied instead of electro-cardiogram(ECG) leads as there is less electrocardiographic artifact from shivering. Defibrillator pads allow rapid detection

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  ECLS is indicated in a HYPOTHERMIC patient(core temperature<30°C[86°F]) with:

HEMODYNAMIC INSTABILITY

HYPOTENSION<90 mmHg AND/OR VENTRICULAR ARRHYTHMIA

OR

HYPOTHERMIC CARDIAC ARREST

 AN ESTIMATED PROBABILITY OF SURVIVAL BY HOPE SCORE ≥10%

https://hypothermicasore.org/

Accidental hypothermia patients with no signs of life can have good outcomes.

DO NOT EXCLUDE PATIENTS WITH

 Hypothermic cardiac arrest is different than normothermic cardiac arrest!In hypothermic cardiac arrest, do not use criteria for ECPR that apply to normothermic patients.

Figure 2. Indications for ECLS rewarming. There is no absolute contraindication to ECLS rewarming of hypothermic CA patients whose core temperature is<30°C. ECLS rewarming of hypothermic CA patients whose core temperature is between 30°C and 32°C, or whose estimated probability of survival by HOPE is<10% may be considered on an exceptional basis. CA, cardiac arrest; ECLS, extracorporeal life support;ECMO, extracorporeal membrane oxygenation; ECPR, extracorporeal cardiopulmonary resuscitation. Figure published with permis-sion(ASAIO).

and treatment of shockable rhythms." Ventricular arrhyth-mias and asystole may be refractory until the patient has been rewarded>30°C.11

In a VA femoro-femoral configuration, the intra-aortic mix-ing point between native cardiac output oxygenated by the lungs and ECMO blood flow via the return cannula moves distally down the aorta as native cardiac output improves.Oxygen saturation and partial pressure of oxygen in the right radial artery are almost equal to the blood perfusing the brain. Pulse oximetry(SpO2) and PaO2 should be measured

in the right arm.39 In HCA, peripheral oxygen saturation(SpO2) and partial pressure of oxygen in arterial blood(PaO2)decrease as native cardiac output improves, reflecting distal movement of the mixing point with more blood flow being partially oxygenated by the injured lung. Differential oxy-genation may occur in a femoro-femoral VA configuration if lung function is impaired by aspiration or trauma. In such conditions, the upper part of the body receives a significantly reduced amount of oxygen, and there is a risk of brain isch-emia. If this occurs, the configuration should be changed to

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Initial management in accidental hypothermia related cardiac arrest before ECLS cannulation

 Figure 3. Initial management in accidental hypothermia-related cardiac arrest before ECLS canulation. CPR, cardiopulmonary resuscita-tion; ECLS, Extracorporeal life support. Figure published with permission(ASAIO).

venoarteriovenous(VAV).39,40 To ensure adequate cerebral perfusion, the target for mean systemic pressure should be between 50 and 70mm Hg. Monitoring with near-infrared spectroscopy(NIRS) should be used to measure cerebral oxygenation.40 Cerebral perfusion pressure should be main-tained by fluid resuscitation with warm, isotonic crystalloid and vasopressors.16 In the initial stages of treatment, there is a great need for fluid therapy. Fluids may be delivered via the

ECLS circuit in the absence of adequate peripheral vascular access.

Surviving victims of avalanches or immersion are at high risk of suffering respiratory complications such as aspiration pneumonia and post-resuscitation chest trauma.41 Protective lung ventilation should be used(Table 2). Infection prevention and treatment are the same as in other patients supported by ECMO.

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Table 2. Ventilator Parameters During ECLS Rewarming

|Usually scale $6.5 ml/ kg$ ideal body weight Rate 10-12/min PEEP any level(5-15cm $H_{2} O$ Plateau pressure<30cm $H_{2} O$ Driving pressure( $\Delta P$ ): plateau pressure-PEEP<15cm $H_{2} O$ ) $FiO_{2}$ 0.3-1.0 (avoiding hypoxia or hyperoxia) $PCO_{2}$ (alpha stat): 4.5-5.5 kpa (35-45mm Hg)| |---|

ECLS,extracorporeal life support; FiO2, fraction of inspired oxy-gen; PCO2, partial pressure of carbon dioxide; PEEP, positive end expiratory pressure.

Anticoagulation should be used to prevent thrombotic compli-cations during ECLS. VA ECMO may be safely managed with no or low levels of anticoagulation for a limited time if there is pro-found coagulopathy. Anticoagulation should be monitored.42-45

● Administer unfractionated heparin or bivalirudin by con-tinuous infusion with activated clotting time(ACT) target 150-180sec, activated partial thromboplastin Time(aPTT)ratio 1.5-2,PTT 60-80 seconds(if using direct thrombin inhibitors), or antiXa(if using Heparin) 0.2-0.3 IU/ml

● If there is a high risk of bleeding, start ECMO without anticoagulant

● Stop anticoagulation if there is excessive bleeding

● Adopt an anticoagulation protocol based on current evidence

● Define priorities in case of bleeding requiring less invasive treatment

Blood gas management should follow institutional proto-cols (Table 3).46-48 Arterial blood gas measurements should use alpha STAT procedure(not temperature-corrected).11,47

The target rewarming rate is up to 5°C/hour to a core tem-perature of 30°C or return of spontaneous circulation(ROSC),whichever occurs first. Further rewarming should follow guidelines for therapeutic hypothermia.49-55 Oxygen arteare-rial outlet temperature should be monitored continuously. A temperature gradient between the venous inflow and arterial outlet of≤4°C, should not be exceeded. The water heater set temperature should not exceed 10°C above the venous inflow temperature, up to a maximum of 42°C. Failure to follow these rules may cause serious neurological complica-tions and hemolysis of blood cells. Core temperature should

be monitored.8,56 Because of warming of the descending aorta and a rapid increase in esophageal temperature, the mea-sured temperature may not reflect the true core temperature.Core temperature should also be monitored at an additional location.54

Consideration of stopping ECLS should be given if there is no ROSC at $32^{\circ} C-35^{\circ} C\left(89.6^{\circ} F-95^{\circ} F\right)$ . The decision to stop treat-ment should also be based on additional clinical information,such as uncontrollable hemorrhage, new information relating to the cause of CA, or signs of severe anoxic brain injury.

Sedation and analgesia may be needed to avoid uncon-trolled awakening, movement, or coughing. Sedation may be reduced or discontinued when normothermia with stable hemodynamic and pulmonary function is achieved.58

Complications

Complications during ECLS are frequent, decreasing sur-vival probability. ${}^{40}$ Complications during ECLS for rewarm-ing are similar to other indications for VA ECMO and include problems with access, systemic circulation, and the circuit. ${}^{57,59}$

In prolonged CA, there is a possibility of chest injury with resultant respiratory failure requiring prolonged mechanical ventilation and extracorporeal membrane support.

Because of metabolic disorders and the pathophysiology of severe hypothermia, there is a possibility of renal failure requiring the use of renal replacement techniques. ${}^{57,59}$

Weaning From ECLS

Cardiac failure is a common finding, presenting as left, right,or combined ventricular stunning.58,59 Inotropes may be added.Serial echocardiography (LV function/concentric contraction)should be used to assess native cardiac output, left ventricular function, and aortic valve opening, and to exclude major val-vular pathologies.

A weaning attempt may be performed once the core tem-perature is $>35^{\circ} C\left(95^{\circ} F\right)$ . With evidence of improved left ventricular ejection fraction by echocardiography and stable hemodynamics, ECLS blood flow may be reduced to 50%,then to 25% of adequate cardiac output. When ECLS support is less than 30% of total, native cardiorespiratory function may

Table 3. Alpha Stat vs. pH Stat in Hypothermia

|Alpha Stat|pH Stat| |---|---| |Named because the ionization state of enzymatic $\alpha$-histidine-imidazole groups is maintained constant Blood gas analysis results are not corrected for body temperature Target="normal" blood gases at 37°C Temperature-corrected hypocarbia and alkalosis tolerated No additional CO, administered to patient Maintains cerebro autoregulation Avoids potential problems of excess cerebral blood flow such as intracranial hypertension and increased microcombolization|So called because pH is maintained at 7.4 regardless of blood temperature Blood gas analysis results corrected for body temperature Target="normal" blood temperature Temperature-uncorrected hypercarbia and acidosis tolerated Additional CO, administered to patient Uncouples cerebral autoregulation Cerebral blood flow increases independent of cerebral metabolic demand that may cause intracranial hypertension and increased microcombolization| |The alkaline pH improves cerebral protection during the ischemic insult|Carbon dioxide causes systemic vasodilatation resulting in faster more homogeneous cooling| |Intracellular trapping of metabolic intermediates and protein function maintained|Counteracts the leftward shift of the hemoglobin-oxygen dissociation curve that occurs with hypothermia and hypothermia-induced alkalemia increases offloading of hemoglobin to the tissues and may increase oxygen delivery which may optimize myocardial function Not preferred strategy in accidental hypothermia|

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be adequate to allow discontinuation of ECLS.59 Weaning from mechanical circulatory support is successful in 30-70% of patients. ${}^{16,59,60}$

Vasopressors and inotropes may be required to counteract vasoplesia and cardiac stunning.

The selection and dosing of inotropes, vasopressors, and inodilators (medications with both inotropic and vasodilator effects) should be tailored to the hemodynamic profile. There is little evidence to support specific practices in this area and considerable variability among institutions including those avoiding inotropic support altogether to rest the heart60-62

However, in CA patients treated with ECRP, use of levosi-mendan in the intensive care unit(ICU) was associated with significantly lower in-hospital mortality, higher rates of wean-ing from ECMO, and substantially lower rates of anoxic brain injury. ${ }^{63,64}$

Weaning may be delayed because of persistent respiratory failure. ${ }^{61}$ In hemodynamically stable patients with persistent respiratory failure, VA ECMO may be converted to venove-nous (VV) ECMO for respiratory support. The weaning strat-egy should be tailored to the needs of individual patients.Extracorporeal treatment of patients in severe hypother-mia involves not only extracorporeal rewarming but also hemodynamic and metabolic stabilization and correction of respiratory disorders. Supplemental information, about circumstances in the field, primary or secondary diagnoses,and the clinical course of the resuscitation process may be helpful.

A post-resuscitation care bundle should be implemented,including adequate oxygenation and ventilation, coronary reperfusion, hemodynamic monitoring and management,reseiz control, temperature regulation, general intensive care management, outcome prediction, and rehabilitation. ${ }^{64}$ Neurologic outcome prediction should be performed in con-sultation with a neurologist once sedation is discontinued.

Outcomes

Hypothermic Cardiac Arrest

Patients with out-of-hospital HCA had better survival with more favorable neurological outcomes than patients with nor-mothermic CA.65 Another study found higher survival(53.8%vs.22.5%) in patients treated with ECLS for hypothermic circu-latory arrest compared with normothermic CA.66 Survival rate ranges from 37% to 85% and a good cerebral outcome may be expected in 80-90% of survivors.8,17,22,30,66,67 Good results have been demonstrated in patients despite the occurrence of fac-tors that are contraindications to the implementation of ECLS in normothermic. Unwitnessed HCA, asystole, long no-flow and low-flow times, age≥70, and low ETCO2 are not contrain-dications to ECLS for HCA.8,16,27,31,32,36 In the study by Podsadilo et al.,68 in the group of patients with unwitnessed HCA, a 27%survival rate was found. Most survivors(83%) have a good neu-rological result. In survivors, in 48% of cases, asystole was the leading rhythm of CA.

Despite the long duration of arrest, the protective role of hypothermia has shown good results in the extracorporeal treatment of patients with HCA.8,69 Saczkowski et al.69 show that the mean time to CA in patients

with a good treatment outcome is 116 minutes. Similarly,Pasquier et al. ${}^{8}$ show a time of 106 minutes in this group of patients. In the literature, there are descriptions of patients with very long periods of HCA, lasting more than 5 hours, which were successfully completed recovery to the use of extracor-poreal treatment. ${}^{70}$

Despite the worse outcomes associated with age, older patients with HCA may survive with good prognosis. Age over 70 should not be a disqualifying factor for extracorporeal treat-ment of patients with severe hypothermia.

Follow-up

The International Hypothermia Registry collects data of hypothermic patients worldwide and evaluates the outcomes.71 Data in hypothermic CA patients, including out-of-hospital and in-hospital data, the mechanism of hypothermic CA, current condition, including core temperature, ECG, duration of CPR,and serum potassium, are used to calculate the survival prob-ability using the HOPE score. ${}^{67}$ Data should also be collected after hospital discharge. These may be useful to re-evaluate sur-vival probabilities in future patients.

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