REVIEW URRENT C OPINION
Salvage techniques in traumatic cardiac arrest: thoracotomy, extracorporeal life support, and therapeutic hypothermia Samuel A. Tisherman
Purpose of review Survival from traumatic cardiac arrest is associated with a very high mortality despite aggressive resuscitation including an Emergency Department thoracotomy (EDT). Novel salvage techniques are needed to improve these outcomes. Recent findings More aggressive out-of-hospital interventions, such as chest decompression or thoracotomy by emergency physicians or anesthesiologists, seem feasible and show some promise for improving outcomes. For trauma patients who suffer severe respiratory failure or refractory cardiac arrest, there seems to be an increasing role for the use of extracorporeal life support (ECLS), utilizing heparin-bonded systems to avoid systemic anticoagulation. The development of exposure hypothermia is associated with poor outcomes in trauma patients, but preclinical studies have consistently demonstrated that mild, therapeutic hypothermia (34 8C) improves survival from severe hemorrhagic shock. Sufficient data exist to justify a clinical trial. For patients who suffer a cardiac arrest refractory to EDT, induction of emergency preservation and resuscitation by rapid cooling to a tympanic membrane temperature of 10 8C may preserve vital organs long enough to allow surgical hemostasis, followed by resuscitation with cardiopulmonary bypass. Summary Salvage techniques, such as earlier thoracotomy, ECLS, and hypothermia, may allow survival from otherwise lethal injuries. Keywords cardiac arrest, extracorporeal circulation, induced hypothermia, thoracotomy, trauma
INTRODUCTION Trauma patients who suffer cardiac arrest have very poor survival. The most common causes of arrest are hemorrhage, tension pneumothorax, and airway obstruction. Standard therapy includes airway management, fluid resuscitation, and tube thoracostomy. In blunt trauma victims with cardiac arrest, some advocate placement of bilateral tube thoracostomies as initial management. With penetrating trauma, surgeons frequently immediately perform an Emergency Department thoracotomy (EDT) via the left chest with the hope of finding a reparable injury in patients who seem to have potential for survival. Simultaneously, a right tube thoracostomy is performed. In a comprehensive review by Rhee et al. [1] of patients who undergo an EDT, overall survival is around 7%, with more than 90% of survivors having normal neurologic function. A recent report confirms that survival with severe www.co-criticalcare.com
neurologic impairment is rare [2]. In general, patients with penetrating injuries fare significantly better than those with blunt trauma [1]. Further, patients with thoracic injuries fare better than those with abdominal trauma. Other factors that affect outcomes include whether or not the patient has signs of life in the field, during transport, or upon arrival at the trauma center and cardiac rhythm.
Departments of Critical Care Medicine and Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, USA Correspondence to Samuel A. Tisherman, MD, FACS, FCCM, Departments of Critical Care Medicine and Surgery, University of Pittsburgh, Suite 1215, Lillian S. Kaufmann Bldg, 3471 Fifth Avenue, Pittsburgh, PA 15213, USA. Tel: +1 412 647 3135; fax: +1 412 578 9340; e-mail: [email protected] Curr Opin Crit Care 2013, 19:594–598 DOI:10.1097/MCC.0000000000000034 Volume 19 Number 6 December 2013
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Salvage techniques in traumatic cardiac arrest Tisherman
KEY POINTS Early chest decompression or thoracotomy outside the hospital by nonsurgeons is feasible and may be beneficial. ECLS can play a role in the management of trauma patients who develop refractory ARDS or profound shock. Therapeutic hypothermia may be beneficial for improving neurologic recovery from traumatic cardiac arrest. Rapid induction of profound hypothermia via aortic flush may preserve vital organs to allow resuscitative surgery and delayed resuscitation via CPB.
The first question regarding patients who suffer a cardiac arrest from trauma is whether or not to initiate resuscitative efforts in the out-of-hospital setting. Based upon outcome data on trauma patients who suffer a cardiac arrest, including results of EDT, the National Association of Emergency Medical Systems Physicians and American College of Surgeons Committee on Trauma have issued recommendations for withholding or terminating resuscitation [3]. For example, resuscitation could be withheld in patients who are pulseless, apneic, and without signs of life (pupillary reflexes, spontaneous movement, or organized electrical activity on electrocardiography). Some have suggested that attempting resuscitation outside of these guidelines does not produce any additional neurologically intact survivors [4]. In contrast, other studies have suggested that initial rhythm may not be a good predictor of survival [5,6]. The differences between these findings could be explained by differences in patient populations and available clinical data. Larger, multicenter retrospective studies or prospective patient registries might help better define who should undergo resuscitative efforts and who should not. The next question is often whether or not to continue resuscitative efforts, specifically EDT, in the Emergency Department. The Western Trauma Association found that there were no survivors if prehospital cardiopulmonary resuscitation (CPR) exceeds 10 min in blunt trauma victims, prehospital CPR exceeds 15 min in penetrating trauma victims, or asystole occurs without pericardial tamponade [7]. Based upon this data, they have developed an evidence-based guideline for when an EDT is indicated [8]. In addition to traumatic cardiac arrest, they recommend EDT for profound refractory shock.
Others have tried to determine better tests that could help identify which patients might benefit from an EDT. For instance, almost 100% of patients who lack cardiac activity by ultrasound in the trauma center do not survive [9]. Given the high risk of death for trauma patients who suffer cardiac arrest despite aggressive, timely resuscitation, including EDT, novel therapies may have a role in improving survival. This article will review the potential use of salvage therapies such as out-of-hospital thoracotomy, extracorporeal life support (ECLS), and hypothermia.
RESUSCITATIVE THORACOTOMY For the patient who suffers a traumatic cardiac arrest, time is of the essence. Many of the patients who suffer a cardiac arrest have tension pneumothoraces. Consequently, medics in some advanced emergency medical services or aeromedical services have been trained to decompress the chest. In one study, chest decompression by thoracostomy (incision or needle) not only identified and treated pneumothoraces, leading to restoration of spontaneous circulation in some cases, but also identified nonsurvivable injuries (massive hemothorax or massive airleak) [10]. The success of needle thoracostomy may depend upon the size of the pneumothorax [11] and chest wall thickness [12]. For patients in extremis in the Emergency Department, tube thoracostomy, either bilateral or right-sided if a thoracotomy is underway, is nearly always indicated. Emergency Department thoracotomy has long been a standard component of resuscitation for the trauma patient who suffers a cardiac arrest and has some potential for survival based upon the criteria discussed above. The goals for EDT include direct cardiac massage to provide optimal CPR, clamping of the descending thoracic aorta to decrease more distal arterial hemorrhage, and direct repair of thoracic injuries. Given the complexity involved in clamping the aorta and repairing injuries, thoracotomies have traditionally only been performed in the Emergency Department or the operating room by surgeons. The Prehospital Care group at Royal London Hospital has developed a protocol for prehospital thoracotomy in patients with cardiac arrest from stab wounds. Emergency physicians or anesthesiologists staff the service and perform the thoracotomy [13]. In their series, the great majority of patients suffered injuries to the right ventricle and had tamponade. The best outcomes resulted when the physician was present as the patient arrested or if the arrest occurred within 5 min of physician arrival.
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The time factor for resuscitation in these circumstances cannot be stressed enough. More experience at other centers will be required before out-ofhospital thoracotomy can be recommended.
EXTRACORPOREAL LIFE SUPPORT ECLS has become a standard means of support for acute respiratory and cardiac failure in the pediatric population. For adults, ECLS is also utilized in some tertiary/quaternary care centers for the management of patients with refractory acute respiratory distress syndrome (ARDS). The landmark Conventional Ventilatory Support versus Extracorporeal Membrane Oxygenation (ECMO) for Severe Adult Respiratory Failure trial demonstrated the benefit of transferring patients with refractory, severe respiratory failure to a center that can provide ECMO [14]. In this situation, veno-venous ECLS is typically employed. For patients who suffer a cardiac arrest or profound shock, for example, after cardiac surgery, veno-arterial ECLS is required in order to provide hemodynamic support [15]. ECLS typically requires systemic anticoagulation to prevent clotting of the circuit, potentially limiting its use in trauma patients who are at risk for bleeding. This risk is highest within the first day or 2 after injury. Clinicians need to balance the potential benefits of ECLS in relation to potential risk. Good data are lacking for developing clear guidelines in this situation. For trauma patients who develop refractory ARDS, ECLS has been used at some centers for many years. The University of Michigan group published a series of 30 patients with ARDS following trauma for which ECLS was utilized [16]. Based upon previous data, they expected a survival rate of less than 20% in these patients, yet 50% survived. ECLS has also been utilized with a heparin-bonded circuit for patients suffering the ‘lethal triad’ of hypothermia, acidosis, and coagulopathy from trauma with pulmonary hemorrhage and hypoxemia [17]. Three of six patients survived. Case reports suggest that the use of ECLS in the presence of traumatic brain injury, which is usually considered an absolute contraindication for anticoagulation, can be well tolerated [18,19]. A more recent case report demonstrated that the Novalung, a low resistance, membrane device that can function via arterial and venous cannulation without a pump, can be used safely without systemic anticoagulation in a patient with multiple trauma, including traumatic brain injury, for CO2 removal [20]. This device has also been successfully used in patients with chest trauma and refractory respiratory failure [21]. 596
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For patients with nontraumatic cardiac arrest or profound shock, there has been variable interest for many years in using ECLS [22]; this has been called extracorporeal CPR. As the main issue in trauma victims is blood loss necessitating massive transfusions and anticoagulation is contraindicated, ECLS has very rarely been used for victims of traumatic cardiac arrest. Nonetheless, in one report ECLS was successfully initiated without any heparin for patients with refractory hemorrhagic shock [23]. Seven patients had pulmonary failure requiring veno-venous ECLS and three had cardiopulmonary failure requiring veno-arterial ECLS. Six survived.
HYPOTHERMIA For patients who suffer nontraumatic cardiac arrest but remain comatose, induction of mild–moderate hypothermia (32–34 8C) can improve outcomes [24]. But is there a role for hypothermia following trauma? One series suggests that carefully selected trauma patients who remain comatose after resuscitation from cardiac arrest may benefit from induced hypothermia [25]. Severely injured trauma victims frequently become hypothermic because of exposure and infusion of cold fluids, and an inability to produce heat because of shock, intoxication, and anesthesia/ sedation. The degree of hypothermia correlates with the severity of injury. Retrospective studies have demonstrated a strong association between the development of hypothermia and mortality, even when injury severity and multiple other factors are controlled for [26,27]. In contrast, many laboratory studies have demonstrated that induction of mild hypothermia, for example 34 8C, can improve mortality from severe hemorrhagic shock [28]. There is no clear explanation for the dichotomy between the laboratory and clinical findings. Despite the statistical manipulations in large retrospective studies, hypothermia may still just be a marker of severity of injury. Perhaps most important physiologically is the difference between uncontrolled, exposure hypothermia in patients, which can be associated with shivering and catecholamine responses, as compared to controlled, therapeutic hypothermia, during which shivering and stress are prevented with sedation. One of the greatest concerns with hypothermia in trauma victims is the potential impact of coagulopathy. However, hypothermia alone does not appear to cause clinically significant coagulation abnormalities until the temperature is less than 34 8C [29]. The only prospective, randomized trial related to hypothermia following trauma compared standard rewarming with a novel continuous Volume 19 Number 6 December 2013
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Salvage techniques in traumatic cardiac arrest Tisherman
arteriovenous rewarming technique in patients who were already hypothermic [30]. Though the number of patients was small, there was a suggestion of short-term (but not long-term) survival benefit with faster rewarming. There have been no prospective studies of therapeutic hypothermia. As mild, therapeutic hypothermia during severe hemorrhagic shock may delay or prevent cardiac arrest, a randomized clinical trial seems warranted.
EMERGENCY PRESERVATION AND RESUSCITATION For trauma victims who suffer cardiac arrest from exsanguination, the greatest challenge is to achieve hemostasis and restore intravascular volume before irreversible ischemic damage has occurred to vital organs, particularly the brain. In some cases, the injuries are just not reparable, but in others, time is the only limitation. Emergency preservation and resuscitation (EPR) has been developed in preclinical studies as a way to preserve vital organs and ‘buy time’ for the trauma surgeon to achieve hemostasis via resuscitative surgery during circulatory arrest [26]. The fastest methods for inducing hypothermia seem to be either a flush of cold, isotonic saline directly into the aorta with the goal of rapidly reducing brain and heart temperature [31], or, alternatively, use of a cardiopulmonary bypass (CPB) circuit with ongoing low-flow [32]. Delayed resuscitation then requires full CPB. The longer the period of hypothermic circulatory arrest that is desired, the deeper the level of hypothermia that is required. Profound hypothermia (10 8C) with glucose and oxygen in the flush can allow good neurologic recovery after even up to 3 h of circulatory arrest [33]. It seems that cooling should be as rapid as possible [34], whereas rewarming should be more moderate [35]. So far, a number of drugs thought to be protective for the brain have been tested in this model. None seem to have significant benefit in this paradigm [36]. It is unclear whether or not specialized fluids can improve outcome as different fluids have not been directly compared [37]. Clinically relevant dog [38] and swine [39] models have demonstrated that EPR has the potential to allow repair and neurologically intact survival from complex injuries. Based on the preclinical studies, investigators at the University of Pittsburgh have developed the EPR for Cardiac Arrest from Trauma (EPR-CAT) feasibility trial (NCT01042015). The study will enroll victims of penetrating trauma who suffer a cardiac arrest within 5 min of arrival at the trauma center, or in the trauma center, yet do not respond to initial
resuscitation, including EDT. These criteria were chosen in an attempt to select patients who have failed conventional therapy yet still might benefit from a novel intervention. The aorta will be cannulated with an arterial ECMO cannula to enable rapid flush of ice-cold, isotonic saline until tympanic membrane temperature is less than 15 8C. At that point, the patient can be rapidly transported to the operating room for resuscitative, damage-control surgery, and delayed resuscitation with CPB. The protocol will require a coordinated effort by emergency physicians, trauma and cardiac surgeons, perfusionists, anesthesiologists, and operating room staff. The primary outcome variable will be survival to hospital discharge without major neurologic disability. As the study progresses, the criteria and the technique may be revised. This trial is designed as a multicenter, feasibility study. Only very busy trauma centers with strong cardiothoracic surgery support will participate. Given the complexities involved in initiating EPR, a selected team of individuals at each site will be trained in the technique. EPR will only be initiated if the trained team members are available. Thus a nonrandomized, concurrent control group will be patients who meet the EPR entry criteria but the EPR team is not available. The strategy will involve enrollment of 10 EPR patients and 10 controls. Data will be analyzed. The protocol may then be revised and another 10 EPR patients and 10 control patients enrolled. This iterative process will continue until the investigators feel that the optimal protocol has been developed. They will then need to consider whether or not a larger, randomized trial is appropriate. This study will be conducted under the regulations for resuscitation research with an exception from informed consent (US Code of Federal Regulations, Section 50.24). The process includes community consultation and public disclosure, which has been completed. The study has been approved by the US Food and Drug Administration, US Army, and the University of Pittsburgh Institutional Review Board. Once training is completed, enrollment will begin.
CONCLUSION Resuscitating trauma victims who suffer cardiac arrest remains very challenging. Few patients survive. Earlier, out-of-hospital interventions, such as chest decompression or thoracotomy, may have an impact, but require either physicians or very advanced medics for implementation. In the Emergency Department, use of ECLS or EPR may allow survival from otherwise lethal injuries.
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Acknowledgements None. Conflicts of interest S.A.T. is the principal investigator of a grant from the US Army, entitled, ‘Emergency Preservation and Resuscitation for Cardiac Arrest from Trauma’, and co-author of a patent submitted, entitled, ‘Emergency Preservation and Resuscitation Methods’.
REFERENCES 1. Rhee PM, Acosta J, Bridgeman A, et al. Survival after emergency department thoracotomy: review of published data from the past 25 years. J Am Coll Surg 2000; 190:288–298. 2. Keller D, Kulp H, Maher Z, et al. Life after near death: long-term outcomes of emergency department thoracotomy survivors. J Trauma Acute Care Surg 2013; 74:1315–1320. 3. Hopson LR, Hirsh E, Delgado J, et al. Guidelines for withholding or termination of resuscitation in prehospital traumatic cardiopulmonary arrest. J Am Coll Surg 2003; 196:475–481. 4. Mollberg NM, Wise SR, Berman K, et al. The consequences of noncompliance with guidelines for withholding or terminating resuscitation in traumatic cardiac arrest patients. J Trauma 2011; 71:997–1002. 5. Leis CC, Herna´ndez CC, Blanco MJG-O, et al. Traumatic cardiac arrest: should advanced life support be initiated? J Trauma Acute Care Surg 2013; 74:634–638. 6. Deasy C, Bray J, Smith K, et al. Traumatic out-of-hospital cardiac arrests in Melbourne. Australia Resuscitation 2012; 83:465–470. 7. Moore EE, Knudson MM, Burlew CC, et al. Defining the limits of resuscitative emergency department thoracotomy: a contemporary Western Trauma Association perspective. J Trauma 2011; 70:334–339. 8. Burlew CC, Moore EE, Moore FA, et al. Western Trauma Association Critical Decisions in Trauma: resuscitative thoracotomy. J Trauma Acute Care Surg 2012; 73:1359–1363. 9. Cureton EL, Yeung LY, Kwan RO, et al. The heart of the matter: utility of ultrasound of cardiac activity during traumatic arrest. J Trauma Acute Care Surg 2012; 73:102–110. 10. Mistry N, Bleetman A, Roberts KJ. Chest decompression during the resuscitation of patients in prehospital traumatic cardiac arrest. Emerg Med J 2009; 26:738–740. 11. Martin M, Satterly S, Inaba K, Blair K. Does needle thoracostomy provide adequate and effective decompression of tension pneumothorax? J Trauma Acute Care Surg 2012; 73:1412–1417. 12. Schroeder E, Valdez C, Krauthamer A, et al. Average chest wall thickness at two anatomic locations in trauma patients. Injury 2013; 44:1183–1185. 13. Davies GE, Lockey DJ. Thirteen survivors of prehospital thoracotomy for penetrating trauma: a prehospital physician-performed resuscitation procedure that can yield good results. J Trauma 2011; 70:E75–E78. 14. Peek GJ, Mugford M, Tiruvoipati R, et al. Efficacy and economic assessment of conventional ventilatory support versus extracorporeal membrane oxygenation for severe adult respiratory failure (CESAR): a multicentre randomised controlled trial. Lancet 2009; 374:1351–1363. 15. Elsharkawy HA, Li L, Esa WAS, et al. Outcome in patients who require venoarterial extracorporeal membrane oxygenation support after cardiac surgery. J Cardiothorac Vasc Anesth 2010; 24:946–951. 16. Michaels AJ, Schriener RJ, Kolla S, et al. Extracorporeal life support in pulmonary failure after trauma. J Trauma 1999; 46:638–645.
598
www.co-criticalcare.com
17. Perchinsky MJ, Long WB, Hill JG, et al. Extracorporeal cardiopulmonary life support with heparin-bonded circuitry in the resuscitation of massively injured trauma patients. Am J Surg 1995; 169:488–491. 18. Friesenecker BE, Peer R, Rieder J, et al. Craniotomy during ECMO in a severely traumatized patient. Acta Neurochir (Wien) 2005; 147:993–996. 19. Reynolds HN, Cottingham C, McCunn M, et al. Extracorporeal lung support in a patient with traumatic brain injury: the benefit of heparin-bonded circuitry. Perfusion 1999; 14:489–493. 20. McKinlay J, Chapman G, Elliot S, Mallick A. Preemptive Novalung-assisted carbon dioxide removal in a patient with chest, head and abdominal injury. Anaesthesia 2008; 63:767–770. 21. Ried M, Bein T, Philipp A, et al. Extracorporeal lung support in trauma patients with severe chest injury and acute lung failure: a 10-year institutional experience. Critical Care 2013; 17:R110. 22. Nichol G, Karmy-Jones R, Salerno C, et al. Systematic review of percutaneous cardiopulmonary bypass for cardiac arrest or cardiogenic shock states. Resuscitation 2006; 70:381–394. 23. Arlt M, Philipp A, Voelkel S, et al. Extracorporeal membrane oxygenation in severe trauma patients with bleeding shock. Resuscitation 2010; 81:804–809. 24. Peberdy MA, Callaway CW, Neumar RW, et al. Part 9: postcardiac arrest care: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation 2010; 122 (18 Suppl 3):S768–786. 25. Tuma MA, Stansbury LG, Stein DM, et al. Induced hypothermia after cardiac arrest in trauma patients: a case series. J Trauma 2011; 71:1524–1527. 26. Tisherman SA. Hypothermia and injury. Curr Opin Crit Care 2004; 10:512– 519. 27. Wang HE, Callaway CW, Peitzman AB, Tisherman SA. Admission hypothermia and outcome after major trauma. Crit Care Med 2005; 33:1296–1301. 28. Wu X, Kochanek PM, Cochran K, et al. Mild hypothermia improves survival after prolonged, traumatic hemorrhagic shock in pigs. J Trauma 2005; 59:291–299. 29. Hess JR, Brohi K, Dutton RP, et al. The coagulopathy of trauma: a review of mechanisms. J Trauma 2008; 65:748–754. 30. Gentilello LM, Jurkovich GJ, Stark MS, et al. Is hypothermia in the victim of major trauma protective or harmful? A randomized, prospective study. Ann Surg 1997; 226:439–447. 31. Woods RJ, Prueckner S, Safar P, et al. Hypothermic aortic arch flush for preservation during exsanguination cardiac arrest of 15 min in dogs. J Trauma 1999; 47:1028–1036. 32. Rhee P, Talon E, Eifert S, et al. Induced hypothermia during emergency department thoracotomy: an animal model. J Trauma 2000; 48:439–447. 33. Wu X, Drabek T, Tisherman SA, et al. Emergency preservation and resuscitation with profound hypothermia, oxygen, and glucose allows reliable neurological recovery after 3 h of cardiac arrest from rapid exsanguination in dogs. J Cereb Blood Flow Metab 2008; 28:302–311. 34. Alam HB, Chen Z, Honma K, et al. The rate of induction of hypothermic arrest determines the outcome in a swine model of lethal hemorrhage. J Trauma 2004; 57:961–969. 35. Alam HB, Rhee P, Honma K, et al. Does the rate of rewarming from profound hypothermic arrest influence the outcome in a swine model of lethal hemorrhage? J Trauma 2006; 60:134–146. 36. Tisherman SA. Suspended animation for resuscitation from exsanguinating hemorrhage. Crit Care Med 2004; 32 (2 Suppl):S46–S50. 37. Taylor MJ, Rhee P, Chen Z, Alam HB. Design of preservation solutions for universal tissue preservation in vivo: demonstration of efficacy in preclinical models of profound hypothermic cardiac arrest. Transplant Proc 2005; 37:303–307. 38. Wu X, Drabek T, Kochanek PM, et al. Induction of profound hypothermia for emergency preservation and resuscitation allows intact survival after cardiac arrest resulting from prolonged lethal hemorrhage and trauma in dogs. Circulation 2006; 113:1974–1982. 39. Sailhamer EA, Chen Z, Ahuja N, et al. Profound hypothermic cardiopulmonary bypass facilitates survival without a high complication rate in a swine model of complex vascular, splenic, and colon injuries. J Am Coll Surg 2007; 204:642–653.
Volume 19 Number 6 December 2013
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Salvage techniques in traumatic cardiac arrest: thoracotomy, extracorporeal life support, and therapeutic hypothermia Samuel A. Tisherman
Purpose of review Survival from traumatic cardiac arrest is associated with a very high mortality despite aggressive resuscitation including an Emergency Department thoracotomy (EDT). Novel salvage techniques are needed to improve these outcomes. Recent findings More aggressive out-of-hospital interventions, such as chest decompression or thoracotomy by emergency physicians or anesthesiologists, seem feasible and show some promise for improving outcomes. For trauma patients who suffer severe respiratory failure or refractory cardiac arrest, there seems to be an increasing role for the use of extracorporeal life support (ECLS), utilizing heparin-bonded systems to avoid systemic anticoagulation. The development of exposure hypothermia is associated with poor outcomes in trauma patients, but preclinical studies have consistently demonstrated that mild, therapeutic hypothermia (34 8C) improves survival from severe hemorrhagic shock. Sufficient data exist to justify a clinical trial. For patients who suffer a cardiac arrest refractory to EDT, induction of emergency preservation and resuscitation by rapid cooling to a tympanic membrane temperature of 10 8C may preserve vital organs long enough to allow surgical hemostasis, followed by resuscitation with cardiopulmonary bypass. Summary Salvage techniques, such as earlier thoracotomy, ECLS, and hypothermia, may allow survival from otherwise lethal injuries. Keywords cardiac arrest, extracorporeal circulation, induced hypothermia, thoracotomy, trauma
INTRODUCTION Trauma patients who suffer cardiac arrest have very poor survival. The most common causes of arrest are hemorrhage, tension pneumothorax, and airway obstruction. Standard therapy includes airway management, fluid resuscitation, and tube thoracostomy. In blunt trauma victims with cardiac arrest, some advocate placement of bilateral tube thoracostomies as initial management. With penetrating trauma, surgeons frequently immediately perform an Emergency Department thoracotomy (EDT) via the left chest with the hope of finding a reparable injury in patients who seem to have potential for survival. Simultaneously, a right tube thoracostomy is performed. In a comprehensive review by Rhee et al. [1] of patients who undergo an EDT, overall survival is around 7%, with more than 90% of survivors having normal neurologic function. A recent report confirms that survival with severe www.co-criticalcare.com
neurologic impairment is rare [2]. In general, patients with penetrating injuries fare significantly better than those with blunt trauma [1]. Further, patients with thoracic injuries fare better than those with abdominal trauma. Other factors that affect outcomes include whether or not the patient has signs of life in the field, during transport, or upon arrival at the trauma center and cardiac rhythm.
Departments of Critical Care Medicine and Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, USA Correspondence to Samuel A. Tisherman, MD, FACS, FCCM, Departments of Critical Care Medicine and Surgery, University of Pittsburgh, Suite 1215, Lillian S. Kaufmann Bldg, 3471 Fifth Avenue, Pittsburgh, PA 15213, USA. Tel: +1 412 647 3135; fax: +1 412 578 9340; e-mail: [email protected] Curr Opin Crit Care 2013, 19:594–598 DOI:10.1097/MCC.0000000000000034 Volume 19 Number 6 December 2013
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Salvage techniques in traumatic cardiac arrest Tisherman
KEY POINTS Early chest decompression or thoracotomy outside the hospital by nonsurgeons is feasible and may be beneficial. ECLS can play a role in the management of trauma patients who develop refractory ARDS or profound shock. Therapeutic hypothermia may be beneficial for improving neurologic recovery from traumatic cardiac arrest. Rapid induction of profound hypothermia via aortic flush may preserve vital organs to allow resuscitative surgery and delayed resuscitation via CPB.
The first question regarding patients who suffer a cardiac arrest from trauma is whether or not to initiate resuscitative efforts in the out-of-hospital setting. Based upon outcome data on trauma patients who suffer a cardiac arrest, including results of EDT, the National Association of Emergency Medical Systems Physicians and American College of Surgeons Committee on Trauma have issued recommendations for withholding or terminating resuscitation [3]. For example, resuscitation could be withheld in patients who are pulseless, apneic, and without signs of life (pupillary reflexes, spontaneous movement, or organized electrical activity on electrocardiography). Some have suggested that attempting resuscitation outside of these guidelines does not produce any additional neurologically intact survivors [4]. In contrast, other studies have suggested that initial rhythm may not be a good predictor of survival [5,6]. The differences between these findings could be explained by differences in patient populations and available clinical data. Larger, multicenter retrospective studies or prospective patient registries might help better define who should undergo resuscitative efforts and who should not. The next question is often whether or not to continue resuscitative efforts, specifically EDT, in the Emergency Department. The Western Trauma Association found that there were no survivors if prehospital cardiopulmonary resuscitation (CPR) exceeds 10 min in blunt trauma victims, prehospital CPR exceeds 15 min in penetrating trauma victims, or asystole occurs without pericardial tamponade [7]. Based upon this data, they have developed an evidence-based guideline for when an EDT is indicated [8]. In addition to traumatic cardiac arrest, they recommend EDT for profound refractory shock.
Others have tried to determine better tests that could help identify which patients might benefit from an EDT. For instance, almost 100% of patients who lack cardiac activity by ultrasound in the trauma center do not survive [9]. Given the high risk of death for trauma patients who suffer cardiac arrest despite aggressive, timely resuscitation, including EDT, novel therapies may have a role in improving survival. This article will review the potential use of salvage therapies such as out-of-hospital thoracotomy, extracorporeal life support (ECLS), and hypothermia.
RESUSCITATIVE THORACOTOMY For the patient who suffers a traumatic cardiac arrest, time is of the essence. Many of the patients who suffer a cardiac arrest have tension pneumothoraces. Consequently, medics in some advanced emergency medical services or aeromedical services have been trained to decompress the chest. In one study, chest decompression by thoracostomy (incision or needle) not only identified and treated pneumothoraces, leading to restoration of spontaneous circulation in some cases, but also identified nonsurvivable injuries (massive hemothorax or massive airleak) [10]. The success of needle thoracostomy may depend upon the size of the pneumothorax [11] and chest wall thickness [12]. For patients in extremis in the Emergency Department, tube thoracostomy, either bilateral or right-sided if a thoracotomy is underway, is nearly always indicated. Emergency Department thoracotomy has long been a standard component of resuscitation for the trauma patient who suffers a cardiac arrest and has some potential for survival based upon the criteria discussed above. The goals for EDT include direct cardiac massage to provide optimal CPR, clamping of the descending thoracic aorta to decrease more distal arterial hemorrhage, and direct repair of thoracic injuries. Given the complexity involved in clamping the aorta and repairing injuries, thoracotomies have traditionally only been performed in the Emergency Department or the operating room by surgeons. The Prehospital Care group at Royal London Hospital has developed a protocol for prehospital thoracotomy in patients with cardiac arrest from stab wounds. Emergency physicians or anesthesiologists staff the service and perform the thoracotomy [13]. In their series, the great majority of patients suffered injuries to the right ventricle and had tamponade. The best outcomes resulted when the physician was present as the patient arrested or if the arrest occurred within 5 min of physician arrival.
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The time factor for resuscitation in these circumstances cannot be stressed enough. More experience at other centers will be required before out-ofhospital thoracotomy can be recommended.
EXTRACORPOREAL LIFE SUPPORT ECLS has become a standard means of support for acute respiratory and cardiac failure in the pediatric population. For adults, ECLS is also utilized in some tertiary/quaternary care centers for the management of patients with refractory acute respiratory distress syndrome (ARDS). The landmark Conventional Ventilatory Support versus Extracorporeal Membrane Oxygenation (ECMO) for Severe Adult Respiratory Failure trial demonstrated the benefit of transferring patients with refractory, severe respiratory failure to a center that can provide ECMO [14]. In this situation, veno-venous ECLS is typically employed. For patients who suffer a cardiac arrest or profound shock, for example, after cardiac surgery, veno-arterial ECLS is required in order to provide hemodynamic support [15]. ECLS typically requires systemic anticoagulation to prevent clotting of the circuit, potentially limiting its use in trauma patients who are at risk for bleeding. This risk is highest within the first day or 2 after injury. Clinicians need to balance the potential benefits of ECLS in relation to potential risk. Good data are lacking for developing clear guidelines in this situation. For trauma patients who develop refractory ARDS, ECLS has been used at some centers for many years. The University of Michigan group published a series of 30 patients with ARDS following trauma for which ECLS was utilized [16]. Based upon previous data, they expected a survival rate of less than 20% in these patients, yet 50% survived. ECLS has also been utilized with a heparin-bonded circuit for patients suffering the ‘lethal triad’ of hypothermia, acidosis, and coagulopathy from trauma with pulmonary hemorrhage and hypoxemia [17]. Three of six patients survived. Case reports suggest that the use of ECLS in the presence of traumatic brain injury, which is usually considered an absolute contraindication for anticoagulation, can be well tolerated [18,19]. A more recent case report demonstrated that the Novalung, a low resistance, membrane device that can function via arterial and venous cannulation without a pump, can be used safely without systemic anticoagulation in a patient with multiple trauma, including traumatic brain injury, for CO2 removal [20]. This device has also been successfully used in patients with chest trauma and refractory respiratory failure [21]. 596
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For patients with nontraumatic cardiac arrest or profound shock, there has been variable interest for many years in using ECLS [22]; this has been called extracorporeal CPR. As the main issue in trauma victims is blood loss necessitating massive transfusions and anticoagulation is contraindicated, ECLS has very rarely been used for victims of traumatic cardiac arrest. Nonetheless, in one report ECLS was successfully initiated without any heparin for patients with refractory hemorrhagic shock [23]. Seven patients had pulmonary failure requiring veno-venous ECLS and three had cardiopulmonary failure requiring veno-arterial ECLS. Six survived.
HYPOTHERMIA For patients who suffer nontraumatic cardiac arrest but remain comatose, induction of mild–moderate hypothermia (32–34 8C) can improve outcomes [24]. But is there a role for hypothermia following trauma? One series suggests that carefully selected trauma patients who remain comatose after resuscitation from cardiac arrest may benefit from induced hypothermia [25]. Severely injured trauma victims frequently become hypothermic because of exposure and infusion of cold fluids, and an inability to produce heat because of shock, intoxication, and anesthesia/ sedation. The degree of hypothermia correlates with the severity of injury. Retrospective studies have demonstrated a strong association between the development of hypothermia and mortality, even when injury severity and multiple other factors are controlled for [26,27]. In contrast, many laboratory studies have demonstrated that induction of mild hypothermia, for example 34 8C, can improve mortality from severe hemorrhagic shock [28]. There is no clear explanation for the dichotomy between the laboratory and clinical findings. Despite the statistical manipulations in large retrospective studies, hypothermia may still just be a marker of severity of injury. Perhaps most important physiologically is the difference between uncontrolled, exposure hypothermia in patients, which can be associated with shivering and catecholamine responses, as compared to controlled, therapeutic hypothermia, during which shivering and stress are prevented with sedation. One of the greatest concerns with hypothermia in trauma victims is the potential impact of coagulopathy. However, hypothermia alone does not appear to cause clinically significant coagulation abnormalities until the temperature is less than 34 8C [29]. The only prospective, randomized trial related to hypothermia following trauma compared standard rewarming with a novel continuous Volume 19 Number 6 December 2013
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Salvage techniques in traumatic cardiac arrest Tisherman
arteriovenous rewarming technique in patients who were already hypothermic [30]. Though the number of patients was small, there was a suggestion of short-term (but not long-term) survival benefit with faster rewarming. There have been no prospective studies of therapeutic hypothermia. As mild, therapeutic hypothermia during severe hemorrhagic shock may delay or prevent cardiac arrest, a randomized clinical trial seems warranted.
EMERGENCY PRESERVATION AND RESUSCITATION For trauma victims who suffer cardiac arrest from exsanguination, the greatest challenge is to achieve hemostasis and restore intravascular volume before irreversible ischemic damage has occurred to vital organs, particularly the brain. In some cases, the injuries are just not reparable, but in others, time is the only limitation. Emergency preservation and resuscitation (EPR) has been developed in preclinical studies as a way to preserve vital organs and ‘buy time’ for the trauma surgeon to achieve hemostasis via resuscitative surgery during circulatory arrest [26]. The fastest methods for inducing hypothermia seem to be either a flush of cold, isotonic saline directly into the aorta with the goal of rapidly reducing brain and heart temperature [31], or, alternatively, use of a cardiopulmonary bypass (CPB) circuit with ongoing low-flow [32]. Delayed resuscitation then requires full CPB. The longer the period of hypothermic circulatory arrest that is desired, the deeper the level of hypothermia that is required. Profound hypothermia (10 8C) with glucose and oxygen in the flush can allow good neurologic recovery after even up to 3 h of circulatory arrest [33]. It seems that cooling should be as rapid as possible [34], whereas rewarming should be more moderate [35]. So far, a number of drugs thought to be protective for the brain have been tested in this model. None seem to have significant benefit in this paradigm [36]. It is unclear whether or not specialized fluids can improve outcome as different fluids have not been directly compared [37]. Clinically relevant dog [38] and swine [39] models have demonstrated that EPR has the potential to allow repair and neurologically intact survival from complex injuries. Based on the preclinical studies, investigators at the University of Pittsburgh have developed the EPR for Cardiac Arrest from Trauma (EPR-CAT) feasibility trial (NCT01042015). The study will enroll victims of penetrating trauma who suffer a cardiac arrest within 5 min of arrival at the trauma center, or in the trauma center, yet do not respond to initial
resuscitation, including EDT. These criteria were chosen in an attempt to select patients who have failed conventional therapy yet still might benefit from a novel intervention. The aorta will be cannulated with an arterial ECMO cannula to enable rapid flush of ice-cold, isotonic saline until tympanic membrane temperature is less than 15 8C. At that point, the patient can be rapidly transported to the operating room for resuscitative, damage-control surgery, and delayed resuscitation with CPB. The protocol will require a coordinated effort by emergency physicians, trauma and cardiac surgeons, perfusionists, anesthesiologists, and operating room staff. The primary outcome variable will be survival to hospital discharge without major neurologic disability. As the study progresses, the criteria and the technique may be revised. This trial is designed as a multicenter, feasibility study. Only very busy trauma centers with strong cardiothoracic surgery support will participate. Given the complexities involved in initiating EPR, a selected team of individuals at each site will be trained in the technique. EPR will only be initiated if the trained team members are available. Thus a nonrandomized, concurrent control group will be patients who meet the EPR entry criteria but the EPR team is not available. The strategy will involve enrollment of 10 EPR patients and 10 controls. Data will be analyzed. The protocol may then be revised and another 10 EPR patients and 10 control patients enrolled. This iterative process will continue until the investigators feel that the optimal protocol has been developed. They will then need to consider whether or not a larger, randomized trial is appropriate. This study will be conducted under the regulations for resuscitation research with an exception from informed consent (US Code of Federal Regulations, Section 50.24). The process includes community consultation and public disclosure, which has been completed. The study has been approved by the US Food and Drug Administration, US Army, and the University of Pittsburgh Institutional Review Board. Once training is completed, enrollment will begin.
CONCLUSION Resuscitating trauma victims who suffer cardiac arrest remains very challenging. Few patients survive. Earlier, out-of-hospital interventions, such as chest decompression or thoracotomy, may have an impact, but require either physicians or very advanced medics for implementation. In the Emergency Department, use of ECLS or EPR may allow survival from otherwise lethal injuries.
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Trauma
Acknowledgements None. Conflicts of interest S.A.T. is the principal investigator of a grant from the US Army, entitled, ‘Emergency Preservation and Resuscitation for Cardiac Arrest from Trauma’, and co-author of a patent submitted, entitled, ‘Emergency Preservation and Resuscitation Methods’.
REFERENCES 1. Rhee PM, Acosta J, Bridgeman A, et al. Survival after emergency department thoracotomy: review of published data from the past 25 years. J Am Coll Surg 2000; 190:288–298. 2. Keller D, Kulp H, Maher Z, et al. Life after near death: long-term outcomes of emergency department thoracotomy survivors. J Trauma Acute Care Surg 2013; 74:1315–1320. 3. Hopson LR, Hirsh E, Delgado J, et al. Guidelines for withholding or termination of resuscitation in prehospital traumatic cardiopulmonary arrest. J Am Coll Surg 2003; 196:475–481. 4. Mollberg NM, Wise SR, Berman K, et al. The consequences of noncompliance with guidelines for withholding or terminating resuscitation in traumatic cardiac arrest patients. J Trauma 2011; 71:997–1002. 5. Leis CC, Herna´ndez CC, Blanco MJG-O, et al. Traumatic cardiac arrest: should advanced life support be initiated? J Trauma Acute Care Surg 2013; 74:634–638. 6. Deasy C, Bray J, Smith K, et al. Traumatic out-of-hospital cardiac arrests in Melbourne. Australia Resuscitation 2012; 83:465–470. 7. Moore EE, Knudson MM, Burlew CC, et al. Defining the limits of resuscitative emergency department thoracotomy: a contemporary Western Trauma Association perspective. J Trauma 2011; 70:334–339. 8. Burlew CC, Moore EE, Moore FA, et al. Western Trauma Association Critical Decisions in Trauma: resuscitative thoracotomy. J Trauma Acute Care Surg 2012; 73:1359–1363. 9. Cureton EL, Yeung LY, Kwan RO, et al. The heart of the matter: utility of ultrasound of cardiac activity during traumatic arrest. J Trauma Acute Care Surg 2012; 73:102–110. 10. Mistry N, Bleetman A, Roberts KJ. Chest decompression during the resuscitation of patients in prehospital traumatic cardiac arrest. Emerg Med J 2009; 26:738–740. 11. Martin M, Satterly S, Inaba K, Blair K. Does needle thoracostomy provide adequate and effective decompression of tension pneumothorax? J Trauma Acute Care Surg 2012; 73:1412–1417. 12. Schroeder E, Valdez C, Krauthamer A, et al. Average chest wall thickness at two anatomic locations in trauma patients. Injury 2013; 44:1183–1185. 13. Davies GE, Lockey DJ. Thirteen survivors of prehospital thoracotomy for penetrating trauma: a prehospital physician-performed resuscitation procedure that can yield good results. J Trauma 2011; 70:E75–E78. 14. Peek GJ, Mugford M, Tiruvoipati R, et al. Efficacy and economic assessment of conventional ventilatory support versus extracorporeal membrane oxygenation for severe adult respiratory failure (CESAR): a multicentre randomised controlled trial. Lancet 2009; 374:1351–1363. 15. Elsharkawy HA, Li L, Esa WAS, et al. Outcome in patients who require venoarterial extracorporeal membrane oxygenation support after cardiac surgery. J Cardiothorac Vasc Anesth 2010; 24:946–951. 16. Michaels AJ, Schriener RJ, Kolla S, et al. Extracorporeal life support in pulmonary failure after trauma. J Trauma 1999; 46:638–645.
598
www.co-criticalcare.com
17. Perchinsky MJ, Long WB, Hill JG, et al. Extracorporeal cardiopulmonary life support with heparin-bonded circuitry in the resuscitation of massively injured trauma patients. Am J Surg 1995; 169:488–491. 18. Friesenecker BE, Peer R, Rieder J, et al. Craniotomy during ECMO in a severely traumatized patient. Acta Neurochir (Wien) 2005; 147:993–996. 19. Reynolds HN, Cottingham C, McCunn M, et al. Extracorporeal lung support in a patient with traumatic brain injury: the benefit of heparin-bonded circuitry. Perfusion 1999; 14:489–493. 20. McKinlay J, Chapman G, Elliot S, Mallick A. Preemptive Novalung-assisted carbon dioxide removal in a patient with chest, head and abdominal injury. Anaesthesia 2008; 63:767–770. 21. Ried M, Bein T, Philipp A, et al. Extracorporeal lung support in trauma patients with severe chest injury and acute lung failure: a 10-year institutional experience. Critical Care 2013; 17:R110. 22. Nichol G, Karmy-Jones R, Salerno C, et al. Systematic review of percutaneous cardiopulmonary bypass for cardiac arrest or cardiogenic shock states. Resuscitation 2006; 70:381–394. 23. Arlt M, Philipp A, Voelkel S, et al. Extracorporeal membrane oxygenation in severe trauma patients with bleeding shock. Resuscitation 2010; 81:804–809. 24. Peberdy MA, Callaway CW, Neumar RW, et al. Part 9: postcardiac arrest care: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation 2010; 122 (18 Suppl 3):S768–786. 25. Tuma MA, Stansbury LG, Stein DM, et al. Induced hypothermia after cardiac arrest in trauma patients: a case series. J Trauma 2011; 71:1524–1527. 26. Tisherman SA. Hypothermia and injury. Curr Opin Crit Care 2004; 10:512– 519. 27. Wang HE, Callaway CW, Peitzman AB, Tisherman SA. Admission hypothermia and outcome after major trauma. Crit Care Med 2005; 33:1296–1301. 28. Wu X, Kochanek PM, Cochran K, et al. Mild hypothermia improves survival after prolonged, traumatic hemorrhagic shock in pigs. J Trauma 2005; 59:291–299. 29. Hess JR, Brohi K, Dutton RP, et al. The coagulopathy of trauma: a review of mechanisms. J Trauma 2008; 65:748–754. 30. Gentilello LM, Jurkovich GJ, Stark MS, et al. Is hypothermia in the victim of major trauma protective or harmful? A randomized, prospective study. Ann Surg 1997; 226:439–447. 31. Woods RJ, Prueckner S, Safar P, et al. Hypothermic aortic arch flush for preservation during exsanguination cardiac arrest of 15 min in dogs. J Trauma 1999; 47:1028–1036. 32. Rhee P, Talon E, Eifert S, et al. Induced hypothermia during emergency department thoracotomy: an animal model. J Trauma 2000; 48:439–447. 33. Wu X, Drabek T, Tisherman SA, et al. Emergency preservation and resuscitation with profound hypothermia, oxygen, and glucose allows reliable neurological recovery after 3 h of cardiac arrest from rapid exsanguination in dogs. J Cereb Blood Flow Metab 2008; 28:302–311. 34. Alam HB, Chen Z, Honma K, et al. The rate of induction of hypothermic arrest determines the outcome in a swine model of lethal hemorrhage. J Trauma 2004; 57:961–969. 35. Alam HB, Rhee P, Honma K, et al. Does the rate of rewarming from profound hypothermic arrest influence the outcome in a swine model of lethal hemorrhage? J Trauma 2006; 60:134–146. 36. Tisherman SA. Suspended animation for resuscitation from exsanguinating hemorrhage. Crit Care Med 2004; 32 (2 Suppl):S46–S50. 37. Taylor MJ, Rhee P, Chen Z, Alam HB. Design of preservation solutions for universal tissue preservation in vivo: demonstration of efficacy in preclinical models of profound hypothermic cardiac arrest. Transplant Proc 2005; 37:303–307. 38. Wu X, Drabek T, Kochanek PM, et al. Induction of profound hypothermia for emergency preservation and resuscitation allows intact survival after cardiac arrest resulting from prolonged lethal hemorrhage and trauma in dogs. Circulation 2006; 113:1974–1982. 39. Sailhamer EA, Chen Z, Ahuja N, et al. Profound hypothermic cardiopulmonary bypass facilitates survival without a high complication rate in a swine model of complex vascular, splenic, and colon injuries. J Am Coll Surg 2007; 204:642–653.
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