Case Report

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American Journal of Emergency Medicine

journal homepage: www. elsevier. com/ locate/ajem

Extracorporeal membrane oxygenation rewarming in the ED: an opportunity for success

Abstract

On average, approximately 1300 Americans die of hypothermia each year [1]. Although accidental hypothermia is commonly associated with severely cold regions or mountain accident victims, hypothermia also commonly occurs in urban centers. Contributing factors often include homelessness, Mental illness, and substance abuse [2]. Hypothermia can profoundly affect the cardiovascular system. As the myocardium cools, the Conduction system slows down, which results in prolonga- tion of the QT interval as well as propensity for arrhythmias. Eventu- ally, bradycardia, atrial fibrillation, and ventricular fibrillation (VF) can develop [3]. The risk of cardiac arrest increases as the core tem- perature drops below 32?C and increases substantially when less than 28?C [2].

The use of extracorporeal membrane oxygenation has been recommended as the Rescue therapy of choice for hypothermic cardiac arrest for its ability to rapidly rewarm patients and provide complete cardiopulmonary support, although reports describing the actual appli- cation of ECMO for hypothermic cardiac arrest in urban centers are rare [4]. We describe a case of a severely hypothermic patient who presented to our urban, academic medical center in refractory cardiac arrest. This patient underwent ECMO rewarming in our emergency department (ED) after more than 3 hours of CPR and had a complete cardiac and Neurologic recovery.

In the winter of 2014, an unidentified male presented to our urban, ac- ademic ED after emergency medical services were dispatched for an unre- sponsive male patient in a warehouse surrounded by drug paraphernalia. On arrival to our ED, the patient was cold, apneic, unresponsive, and found to be in VF on the cardiac monitor. There were no signs of trauma, and the patient lacked pulses. Chest compressions were immediately started. Peripheral and central intravenous access was obtained, and the patient was intubated. Active rewarming measures including warm intravenous fluids, warm water orogastric and Foley lavage, and warm humidified oxygen via the ventilator were initiated after Foley catheter temperature probe revealed a core tempera- ture of 27?C. The patient received multiple doses of naloxone, epi- nephrine, and bicarbonate and was defibrillated without success.

Despite the above measures, the patient remained in refractory VF and his temperature never rose above 30?C. With CPR, the patient dem- onstrated occasional purposeful movement, including reaching for his endotracheal tube. Initial arterial blood gas and laboratory results showed the following: pH 6.89, PaO2 20 mm Hg, PaCO2 99 mm Hg, potas- sium 3.4 mmol/L, and lactate 14.1 mmol/L.

After approximately 100 minutes of unsuccessful resuscitation, the cardiothoracic (CT) surgery team was consulted for ECMO rewarming.

The CT surgeon performed bilateral femoral cut downs and initiated venous-arterial ECMO in the ED. Once optimal flow rates were achieved, CPR was terminated, approximately 3 hours and 20 minutes after the patient had arrived in our ED.

After initiation of ECMO, medical management was assumed by the critical care and CT surgery teams; and the patient was admitted to the ICU where rewarming continued through venous-arterial ECMO. Once the patient was warmed to 36?C, he was defibrillated using 360 J to nor- mal sinus rhythm. On hospital day 2, the patient was successfully weaned off of ECMO; and on day 3, he was extubated. The patient was transferred out of the ICU on day 6. He was discharged to home on hos- pital day 15 at his baseline neurologic and cardiac status.

When conventional attempts using active external and minimally invasive rewarming strategies fail to warm a hypothermic patient in cardiac arrest, the ED practitioner is left with several more invasive options such as large body cavity lavage with peritoneal catheter and Chest tubes, endovascular devices, thoracotomy, extracorporeal heating sys- tems, and cardiopulmonary bypass. Recently, ECMO has been touted as the rescue therapy of choice for hypothermic cardiac arrest, although clinical evidence supporting its use in this scenario remains limited [3-5]. Advan- tages of ECMO over other methods include its ability to rapidly warm core temperatures up to 8? to 12?/h while providing complete hemody- namic support and oxygenation, reducing the risk of pulmonary injury in patients already at high risk for pulmonary edema [3,5].

Hypothermic patients with cardiac arrest have a rate of survival of 50% with the use ECMO, whereas, at centers without ECMO, these same types of patients have a survival rate of only 10% [5]. Furthermore, among patients treated with ECMO or cardiopulmonary bypass, the rate of survival without neurologic compromise is 47% to 63% [5]. Cases of survival with a good clinical outcome have been reported with core temperatures as low as 13?C and in cases requiring long transport with more than 5 hours of CPR [3,5-7].

The decision to resuscitate in a prehospital setting or continue re- suscitation in the ED for a hypothermic patient in cardiac arrest is not always straightforward. Not every hypothermic patient in cardiac arrest is likely to benefit from aggressive therapy. Furthermore, ar- ranging ECMO and potentially transferring a patient in cardiac arrest with the need for continuous CPR to an ECMO center are challenging. Several factors have been shown to predict poor outcomes in these patients [5]. They include a clear history of cardiac arrest before cooling, obvious signs of irreversible death, core body temperature higher than 32?C with asystole, and potassium greater than 12 mEq/L [5]. Patients with any of these findings are not likely salvage- able and are thus unlikely to benefit from aggressive management such as the use of ECMO.

0735-6757/(C) 2014

In our case, we decided to pursue ECMO because the patient did not meet any of the above criteria and less invasive measures failed to warm the patient. With occasional purposeful movement, the patient demon- strated intact neurologic function, suggesting the likelihood of a Good neurologic outcome.

This case highlights the critical role of emergency physicians in iden- tifying patients likely to benefit from ECMO rewarming in hypothermia- associated cardiac arrest and coordinating their therapy. Furthermore, the case demonstrates that ECMO can be successfully initiated at the bedside in the ED by a Multidisciplinary team and adds to the growing body of literature about the effectiveness of this therapy, even after a long duration of CPR.

Catherine Ginty, MD Department of Emergency Medicine, Cooper Medical School of Rowan University, Cooper University Hospital, One Cooper Plaza, Camden, NJ

08103, USA

Corresponding author. Cooper University Hospital Department of Emergency Medicine One Cooper Plaza Kelemen 152 Camden, NJ 08103 U.S.A.

Tel.:+001 215 292 9180

E-mail address: [email protected]

Adarsh Srivastava, MD Department of Emergency Medicine, Division of Critical Care University of Cincinnati College of Medicine 231 Albert Sabin Way Cincinnati, OH 45267-0769 U.S.A.

Michael Rosenbloom, MD Department of Surgery, Division of Cardiothoracic Surgery, Cooper Medical School of Rowan University, Cooper University Hospital, One Cooper Plaza

Camden, NJ 08103, USA

Sally Fowler, B.S

Cooper University Hospital Heart Institute, Cardiovascular Perfusion

Lisa Filippone, MD Department of Emergency Medicine, Cooper Medical School of Rowan University, Cooper University Hospital, One Cooper Plaza,

Camden, NJ 08103, USA

http://dx.doi.org/10.1016/j.ajem.2014.11.045

References

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