Damage control resuscitation: A sensible approach to the exsanguinating surgical patient MAJ (P) Alec C. Beekley, MD, FACS T he term ���resuscitation��� has evolved in modern medical lexicon to encompass the en- tire spectrum of care delivered to a surgical patient in physiological dis- tress or shock. Far from just the amount and type of fluids used, this spectrum of care includes a standard and finite set of invasive interventions during the initial primary survey of the injured patient, the diagnostic means used to discover sources of injury and shock, the advanced surgical interventions used to treat these injuries, the reversal of hypothermia, the correction of acidosis, and the replace- ment of intravascular volume, oxygen- carrying capacity, and coagulation fac- tors. However, for the purposes of this article, ���resuscitation��� refers to the non- surgical strategies used to prevent or re- verse anemia, coagulopathy, acidosis, and hypothermia in the presentation and ini- tial 24 to 48 hrs of care of the severely injured patient. With the advent of modern blood cen- trifuge, preservation, and banking, the major logistic hurdle involved in having rapidly available blood products on hand for injured patients was largely over- come. At roughly the same time, it was discovered that relatively simple isotonic crystalloid solutions could provide initial and, in many cases, adequate resuscita- tion for most injured casualties. The ad- ministration of isotonic crystalloid solu- tions to acutely injured patients has become a standard practice that remains in the Advanced Trauma Life Support courses taught today (1). Until recently, massive transfusion guidelines for the ra- tio of various products administered were based on the assumption that the coagu- lopathy encountered in severely injured patients was primarily from dilution of blood clotting constituents and did not occur until at least one blood volume had been transfused (2). The notions that substantial volumes of isotonic crystalloid solutions are ac- ceptable for severely injured patients and that coagulopathy is primarily a byprod- uct of resuscitation have recently been challenged (3). Several recent articles from major civilian and military trauma centers have demonstrated that severely injured casualties have a significant co- agulopathy on presentation (4���6). Not surprisingly, these severely injured pa- tients are also the ones most likely to experience hypothermia and acidosis. Ad- herence to the traditional practice of ad- ministering isotonic crystalloids followed by packed red blood cells (PRBCs) until a either a predetermined threshold of PRBCs is reached or until fresh frozen plasma can be thawed results in a worsening of all three aspects of the ���lethal triad.��� In many of the classic papers that de- scribe reversing the ���lethal triad��� of hy- pothermia, acidosis, and coagulopathy with ���damage control��� approaches, the authors break down the various aspects of the damage control process into se- quences or steps for simplicity (7���9). An unfortunate byproduct of describing the damage control sequence in phases is the potential inference that correction of the hypothermia, acidosis, and coagu- lopathy is the ���secondary resuscitation,��� which does not begin in earnest until the patient reaches an intensive care unit. From the Madigan Army Medical Center, Tacoma, WA. The opinions and assertions contained in this ar- ticle are solely the author���s private ones and are not to be construed as official or reflecting the views of the U.S. Army or the Department of Defense. The author has not disclosed any potential con- flicts of interest. For information regarding this article, E-mail: alec.beekley@us.army.mil Copyright �� 2008 by the Society of Critical Care Medicine and Lippincott Williams & Wilkins DOI: 10.1097/CCM.0b013e31817da7dc Background: The current wars in Iraq and Afghanistan have resulted in the highest rates of combat casualties experienced by the U.S. military since the Vietnam conflict. These casualties suffer wounds that have no common civilian equivalent and more frequently require massive transfusion (greater than 10 units of packed red blood cells [PRBCs] in less than 24 hrs) than civilian injured. Discussion: Military surgeons have found that traditional ap- proaches to resuscitation, particularly in terms of the ratio of blood products to each other and the timing of these products, often fail to effectively treat the coagulopathy that is present on arrival in these casualties. This observation has been concurrently noted in the civilian trauma literature. These experiences have ignited interest in an alternative approach to the resuscitation of these most grievously injured patients. This approach includes the use of permissive hypotension the prevention and aggressive treatment of hypothermia with both passive and active warming measures the temporization of acidosis with use of exogenous buffer agents the immediate use of thawed plasma in ratios ap- proaching 1:1 with PRBCs the early use of platelets, often given well before 10 units of PRBCs have been transfused the early use of recombinant Factor VIIa and, in military settings, the use of fresh whole blood as a primary resuscitation fluid. This strategy has been called ���damage control resuscitation��� to emphasize its pairing with damage control surgical techniques. Summary: Review of the published support for this strategy reveals that additional trials are needed to study and optimize these techniques. (Crit Care Med 2008 36[Suppl.]:S267���S274) KEY WORDS: damage control resuscitation massive transfusion exsanguination fresh thawed plasma fresh whole blood hemo- static resuscitation hypotensive resuscitation permissive hypo- tension coagulopathy lethal triad S267 Crit Care Med 2008 Vol. 36, No. 7 (Suppl.)

The emphasis in many of these papers is on the very concept of delaying definitive surgical treatment until the patient���s hy- pothermia, acidosis, and coagulopathy are treated and on the surgical tech- niques used to perform an abbreviated operation. The intraoperative resuscita- tion strategies described often featured initial resuscitation with crystalloid, transition to PRBCs for continued evi- dence of shock, and addition of plasma and platelets into the resuscitation strat- egy only after a certain threshold of PRBC numbers (for example, 8���10) had been reached (8). That this resuscitation strategy fails to treat and in fact worsens the hypother- mia, acidosis, and coagulopathy that are associated with severe trauma has been recently noted by several authors, includ- ing surgeons deployed in the global war on terrorism (10, 11). An alternative strategy, aptly named ���damage control resuscitation��� to emphasize its pairing with damage control surgical techniques, is described and is currently in use in Operations Iraqi and Enduring Freedom. This strategy includes the tolerance of moderate hypotension (systolic blood pressure approximately 90 mm Hg) the trauma system-wide emphasis on the rec- ognition and prevention of hypothermia the temporization of acidosis (or at least prevention of worsening acidosis) and the emphasis on immediate correction of coagulopathy as the most treatable arm of the ���lethal triad.��� The treatment of coagulopathy features appropriate choices of resuscitation fluids the amounts and ratio of these products to one another the timing of the delivery of these products and the use of adjuncts to resuscitation (for example, recombinant Factor VIIa). Clearly, for this resuscita- tion strategy to be successful, it must be married to the treatment of immediately life-threatening conditions (for example, tension pneumothorax) and the rapid surgical control of hemorrhage. The majority ( 90%) of trauma pa- tients treated in both civilian and military settings do not require damage control surgical techniques or massive transfu- sion (defined as 10 units PRBCs in 24 hrs for this article) (12). Although it has been demonstrated that up to 28% of these patients may have an abnormal ProTime on arrival (5), more recent data suggest that thromboelastography may be superior to standard assays (such as ProTime and partial thromboplastin time) in detecting a hypercoagulable state early after injury in less severely injured patients (13). Hence, managing hypercoagulability may be more critical in the majority of less severely injured trauma patients. The need for massive transfusion is relatively rare, occurring in only 1% to 2% of civilian trauma patients (14), but up to 7% of patients in current military settings (11). However, these pa- tients are the most at risk for early death from hemorrhage and stand to benefit from alternative strategy that begins to treat their physiological derangements as soon as they arrive (and preferably before they arrive). Permissive Hypotension The concept that the combination of the patient���s natural coagulation cascade, hypotension, and vessel spasm will tem- porarily arrest traumatic hemorrhage is perhaps no better illustrated than in the combat casualty with proximal limb am- putations from an explosion. These pa- tients often arrive without apparent bleeding from traumatically amputated limbs, only to have rapid arterial bleeding resume once resuscitation begins and hy- potension is corrected to normal systolic pressures. This bleeding will sometimes overwhelm tourniquet control (15). This phenomenon was well known and previ- ously described by World War I and II era surgeons (16). Several terms have been coined to describe the strategy of allow- ing hypotension in trauma victims before the establishment of surgical hemor- rhage control. These terms include hypo- tensive resuscitation, deliberate hypoten- sion, and permissive hypotension undoubtedly there are others. Both ani- mal and human clinical studies have also supported this concept, although mixed results have been noted in clinical studies (17���28). Nevertheless, current military doctrine and training emphasize mini- mizing fluid and blood product delivery in the prehospital setting in combat ca- sualties who have a palpable radial pulse and have normal mental status (29, 30). This approach is also used in the trauma bays at forward surgical teams and com- bat support hospitals to prevent unneces- sary blood loss before surgical control is obtained. Hypothermia The dramatic and negative association that hypothermia has with the survival of severely injured trauma patients is well described. Severe trauma-related hypo- thermia (temperature 32��C) has been associated with 100% mortality (31). The effect of hypothermia on the coagulation system is multifactorial (32, 33). Moder- ate hypothermia (32��C to 34��C) directly reduces coagulation factor activity ap- proximately 10% for each degree Celsius decrease in temperature while markedly affecting platelet function (34���36). Se- verely injured trauma patients with hem- orrhagic shock typically have uncoupling of normal metabolic pathways, resulting in the loss of homeothermic ability. This loss of thermoregulation can be exacer- bated in the prehospital setting by envi- ronmental factors, prolonged extrication or scene time, intoxication, and convec- tive heat losses (for example, open heli- copter door during flight). Both civilian and military trauma centers have linked the presence of hypothermia on arrival with increased mortality (37���39). Hypothermia in combat casualties was identified as a theaterwide trauma system problem in Operation Iraqi Freedom (40, 41). Several measures were subsequently put in place system-wide to prevent hy- pothermia. First, simple hypothermia prevention measures were disseminated to the combat medics on the battlefield. These measures included emphasis on ex- ternal hemorrhage control as the first priority, limiting removal of clothing to areas of the body that require treatment, wrapping treated casualties in wool or solar blankets, and the use of inline fluid warmers such as the Thermal Angel (Es- till Medical Technologies, Dallas, TX). Measures to prevent and treat hypother- mia at the initial levels of surgical care (forward surgical teams and combat sup- port hospitals) include the use of stan- dardized heat-loss prevention kits (use of solar blankets, heated blankets, and body bag[s]), the use of warmed blood prod- ucts and fluids, and the use of fluid warmers/rapid infusers (for example, the Thermal Angel [Estill Medical Technolo- gies, Inc., Dallas, TX] and the Belmont Rapid Infuser [Belmont Instrument Cor- poration, Billerica, MA]). Since institu- tion of standardized hypothermia preven- tion measures, the rate of patients arriving to the combat support hospitals with hypothermia has dropped from 7% to less than 1% (41). Hence, severe hypothermia has be- come a relative rarity in Operation Iraqi Freedom. The system measures in place allow prevention of additional heat loss in prehospital settings and prevention and S268 Crit Care Med 2008 Vol. 36, No. 7 (Suppl.)