INTRODUCTION — In the setting of trauma, loss of circulating blood volume from hemorrhage is the most common cause of shock. Inadequate oxygenation, mechanical obstruction (eg, cardiac tamponade, tension pneumothorax), neurologic dysfunction (eg, high-spinal cord injury), and cardiac dysfunction represent other potential causes or contributing factors [1]. Hemorrhagic shock is a common and frequently treatable cause of death in injured patients and is second only to traumatic brain injury as the leading cause of death from trauma [2,3].
This topic will review the initial management of hemorrhagic shock in the adult trauma patient. General management of the adult trauma patient, subsequent management of trauma-related hemorrhage, and other aspects of shock, including management of non-hemorrhagic shock, pathophysiology, and differential diagnosis, are discussed separately.
●(See "Initial management of trauma in adults".)
●(See "Coagulopathy in trauma patients".)
●(See "Definition, classification, etiology, and pathophysiology of shock in adults".)
●(See "Approach to shock in the adult trauma patient".)
CLASSIFICATION OF HEMORRHAGE — The Advanced Trauma Life Support (ATLS) manual produced by the American College of Surgeons describes four classes of hemorrhage to emphasize the early signs of the shock state [3]. Clinicians should note that significant drops in blood pressure are generally not manifested until Class III hemorrhage develops, and up to 30 percent of a patient's blood volume can be lost before this occurs. (See "Approach to shock in the adult trauma patient", section on 'Pathophysiology'.)
●Class I hemorrhage involves a blood volume loss of up to 15 percent. The heart rate is minimally elevated or normal, and there is no change in blood pressure, pulse pressure, or respiratory rate.
●Class II hemorrhage occurs when there is a 15 to 30 percent blood volume loss and is manifested clinically as tachycardia (heart rate of 100 to 120), tachypnea (respiratory rate of 20 to 24), and a decreased pulse pressure, although systolic blood pressure (SBP) changes minimally if at all. The skin may be cool and clammy, and capillary refill may be delayed. This can be considered moderate hemorrhage.
●Class III hemorrhage involves a 30 to 40 percent blood volume loss, resulting in a significant drop in blood pressure and changes in mental status. Any hypotension (SBP less than 90 mmHg) or drop in blood pressure greater than 20 to 30 percent of the measurement at presentation is cause for concern. While diminished anxiety or pain may contribute to such a drop, the clinician must assume it is due to hemorrhage until proven otherwise. Heart rate (≥120 and thready) and respiratory rate are markedly elevated, while urine output is diminished. Capillary refill is delayed. Both class III and class IV should be considered severe hemorrhage.
●Class IV hemorrhage involves more than 40 percent blood volume loss leading to significant depression in blood pressure and mental status. Most patients in Class IV shock are hypotensive (SBP less than 90 mmHg). Pulse pressure is narrowed (≤25 mmHg), and tachycardia is marked (>120 beats per minute). Urine output is minimal or absent. The skin is cold and pale, and capillary refill is delayed.
INITIAL ASSESSMENT AND INTERVENTIONS — Initial management of the adult trauma patient in shock is focused on the following:
●Recognizing and reversing life-threatening injuries (eg, tension pneumothorax, cardiac tamponade) immediately (see "Approach to shock in the adult trauma patient", section on 'Clinical features of shock')
●Preventing or limiting ongoing blood loss (see 'Initial management of hemorrhage' below)
●Restoring intravascular volume if necessary
●Maintaining adequate oxygen delivery to vital organs
Assessment and treatment are performed simultaneously in the seriously injured patient (algorithm 1). Management of the adult trauma patient and the assessment of traumatic shock are reviewed in greater detail separately. Important interventions for the adult with hemorrhagic shock due to trauma are discussed below. (See "Initial management of trauma in adults" and "Approach to shock in the adult trauma patient".)
Direct pressure is the primary and preferred means for controlling external hemorrhage. A tourniquet may be required to control bleeding from a severe extremity injury. (See 'Initial management of hemorrhage' below.)
Vascular access is obtained as rapidly as possible. Two short, large-bore (16-gauge or larger) intravenous (IV) lines placed in the antecubital region are ideal but not always possible. Intraosseous devices can be placed rapidly and offer an effective alternative when there is difficulty placing an IV catheter. (See "Peripheral venous access in adults" and "Intraosseous infusion".)
Placement of a central venous catheter (size 8 French) can be performed when adequate peripheral access cannot be obtained and allows measurement of central venous pressure. Central line placement under ultrasound guidance offers high success rates with fewer complications than procedures performed without ultrasound [4,5]. Ultrasound-guided placement of peripheral venous catheters is a reasonable approach. Some experts advocate use of distal saphenous vein cutdowns due to ease of access and consistency of anatomy [6]. (See "Principles of ultrasound-guided venous access" and "Central venous access: General principles".)
Traumatic shock occurs most often from hemorrhage. Massive hemorrhage can occur in the chest, abdomen, retroperitoneum, and from major external wounds. The thigh can hold up to approximately 1 L of blood. Scalp lacerations can bleed profusely and are often overlooked. Causes of shock in trauma are provided in the table and discussed separately (table 1). (See "Approach to shock in the adult trauma patient".)
Ultrasound is an integral part of the initial evaluation of the trauma patient and reliably identifies free intra-abdominal and pericardial fluid in the hands of proficient ultrasonographers [7]. During the initial resuscitation, the extended Focused Assessment with Sonography for Trauma (E-FAST) exam is performed to assess first for pericardial blood and then for intraperitoneal bleeding and pneumothorax. (See "Emergency ultrasound in adults with abdominal and thoracic trauma".)
Ultrasound has largely replaced diagnostic peritoneal lavage (DPL) in the initial assessment of the trauma patient, although DPL may retain a role in specific circumstances. If ultrasound is unavailable or its findings are equivocal or inconsistent with the clinical picture, a DPL or diagnostic peritoneal tap (DPT) can provide important information. (See "Initial evaluation and management of blunt abdominal trauma in adults", section on 'Diagnostic peritoneal lavage' and "Pelvic trauma: Initial evaluation and management", section on 'Diagnostic tests'.)
INITIAL MANAGEMENT OF HEMORRHAGE
Control of compressible or extremity bleeding — Bleeding from external wounds must be controlled as rapidly as possible. Direct pressure is the primary and preferred means for controlling external hemorrhage. While clamping bleeding vessels under direct visualization is acceptable when necessary, blind clamping should not be performed. Scalp lacerations can bleed profusely and are often overlooked if significant thoracic or abdominal injuries are present. Scalp lacerations can be managed by injecting lidocaine with epinephrine directly into the wound, by placing clips (eg, Raney clips (picture 1)), or by closing the wound with running (ie, non-interrupted) or running locked stitches using heavy suture. Running or interrupted sutures may also be used to control severe bleeding from extremity wounds when direct pressure is inadequate and the few available clinicians must perform other important interventions for an unstable trauma patient.
Use of a tourniquet is acceptable to stop hemorrhage in cases of amputation or severe extremity injury when other measures have not successfully controlled bleeding. Tourniquets should be released periodically (eg, every 45 minutes) when possible to avoid prolonged ischemia and possible tissue loss. (See "Severe lower extremity injury in the adult patient", section on 'Control of hemorrhage'.)
Hemorrhage from pelvic fracture — Unstable pelvic fractures and associated vascular injuries can cause hemorrhagic shock. Preliminary stabilization of the pelvis by applying a circumferential pelvic binder or tying a sheet firmly around the pelvis can reduce bleeding. Such interventions are most important with "open-book" pelvic fractures (in which the symphysis pubis is disrupted [≥2.5 cm], the pelvis opened, and the retroperitoneal space enlarged) (image 1). In addition to immediate orthopedic consultation, interventional radiology and vascular surgery may be needed to help control hemorrhage. When available, resuscitative endovascular balloon occlusion of the aorta (REBOA) has demonstrated favorable outcomes in patients with massive bleeding from pelvic trauma.(See "Pelvic trauma: Initial evaluation and management", section on 'Management' and "Endovascular methods for aortic control in trauma", section on 'Pelvic trauma at risk for hemodynamic collapse' and "Severe pelvic fracture in the adult trauma patient", section on 'Management'.)
Control of non-compressible bleeding — Methods for identifying noncompressible bleeding include focused abdominal sonography for trauma (FAST) for the abdomen, chest radiograph for the chest, and computed tomography (CT) for the retroperitoneal space. Hemodynamically stable patients can undergo CT for further assessment. Unstable patients should be stabilized either by resuscitation in the operating room or, in some situations, with REBOA prior to going to the CT scanner. (See "Endovascular methods for aortic control in trauma" and "Overview of damage control surgery and resuscitation in patients sustaining severe injury", section on 'Damage control surgery'.)
Early determination of disposition — Definitive management of the patient with traumatic shock often requires emergency surgery. Emergency clinicians should consult a trauma surgeon as soon as possible for all victims of significant trauma who may require operative or critical care interventions. If the patient must be transferred for definitive care, early communication with a trauma center and preparation for transfer is performed concurrently with assessment and stabilization. (See 'Disposition' below.)
RESUSCITATION AND TRANSFUSION — The management of hemorrhage in the adult trauma patient will vary depending upon the known or suspected injuries, vital signs, extent of hemorrhage, available resources, and need for transfer.
Key principles — A few key principles guide the management of hemorrhage due to trauma:
●Control compressible and extremity bleeding
●Minimize the use of intravenous (IV) fluids in the resuscitation of trauma patients. Give IV fluids only for the resuscitation of hypotensive patients (eg, MAP <65), and then only until blood is available
●Transfuse blood products as soon as the need is recognized.
●Blood products (ie, red blood cells, plasma [clotting factors], and platelets) should be given in equivalent amounts – in other words, in a 1:1:1 ratio. Whole blood can be used if available [8].
●Rapidly mobilize all needed resources (eg, surgery, anesthesia, blood bank, transfer to trauma center).
●Use thromboelastography, or comparable rapid point-of-care assessment of coagulation, to guide trauma resuscitation whenever possible. (See "Coagulopathy in trauma patients".)
Treatment of hemorrhage with IV crystalloid increases the risk of coagulopathy from dilution of clotting factors and platelets, and possibly hypothermia. To avoid these complications in injured patients, treatment with IV fluid should be avoided whenever possible and, if unavoidable, given in the smallest volumes necessary, until blood products become available. The choice of fluid remains a subject of debate and such issues are discussed below. (See 'Intravenous fluid resuscitation' below.)
Trauma patients with severe hemorrhage need blood. To limit the adverse systemic effects of injury (eg, coagulopathy) and minimize the risks associated with large-scale transfusion, blood products – red blood cells, plasma, and platelets – are best given in a ratio of 1:1:1. The evidence supporting this approach is reviewed in detail separately. (See "Massive blood transfusion", section on 'Trauma'.)
The reduction in mortality observed in severely hemorrhaging trauma patients that received higher ratios of plasma and platelets to packed red blood cells (PRBCs) has contributed to the development of "Damage Control Resuscitation" (DCR), often used in combination with Damage Control Surgery. The goal of DCR is to control hemorrhage rapidly and prevent coagulopathy by minimizing crystalloid use and transfusing early, using relatively high ratios of plasma and platelets to red blood cells [9-11]. This may entail allowing patients to remain relatively hypotensive during some portion of their resuscitation (so-called permissive hypotension) [11]. (See "Overview of damage control surgery and resuscitation in patients sustaining severe injury".)
These guiding principles apply to all adult trauma patients, although their application and the details of management will vary according to the clinical scenario. Specific guidance for important and common clinical scenarios is provided below.
Transfusion of blood products — Blood products should be given as soon as the need for transfusion is recognized. When to begin blood transfusion, depends on clinical circumstances. As an example, immediate transfusion of PRBCs, plasma, and platelets is needed when exsanguination is imminent, such as a patient with a thoracic injury whose chest tube releases over 2 L of blood upon placement. Another patient with a self-inflicted wrist laceration may not require any blood, despite being hypotensive, because hemorrhage is promptly controlled, the wound is easily repaired, and comorbidities are absent. Thus, the best approach to transfusion varies by clinical scenario; common and important scenarios are reviewed below. (See 'Management by clinical scenario' below.)
Typed and cross-matched PRBCs are best, but can require significant time to prepare. If warranted by the patient's condition, clinicians can transfuse immediately using emergency-release blood. Type O RhD-negative is the universal donor and can be given to all individuals. Girls and women of childbearing age should be given O-negative blood if available to reduce the risk of developing antibodies to RhD that could cause hemolytic disease of the fetus and newborn in the future. Type O RhD-positive blood can be used for women for whom childbearing is not a consideration and for men. (See "Pretransfusion testing for red blood cell transfusion" and "RhD alloimmunization in pregnancy: Overview".)
Preparation of fully typed and cross-matched blood may require 20 minutes or more. Type-specific blood can usually be obtained within 15 to 20 minutes. In general, type O blood is available immediately, depending on transport time from the blood bank to the ED. Trauma centers often store type O blood in refrigerators in the ED.
The safety of the blood supply continues to improve, and although some risk of transmitting infectious agents persists, such events are rare. Transfusion-associated infection is discussed separately. (See "Transfusion-transmitted bacterial infection" and "Blood donor screening: Laboratory testing".)
Intravenous fluid resuscitation — Fluid resuscitation in trauma, including the optimal type and volume, remains the subject of considerable debate. With severely injured patients, our goal is to minimize crystalloid administration, while avoiding significant hypotension, until blood is available. The transition from crystalloid to blood should occur as early as possible in unstable trauma patients. Excessive infusion of crystalloid (ie, ratio of crystalloid to PRBCs >1.5:1 or volume of crystalloid >1 L) has been associated with worse outcomes in patients with severe hemorrhage, according to observational data, and should be avoided [12-14].
Many hospitals have blood products immediately available in the emergency department (ED). In such hospitals, immediate transfusion of blood products, rather than fluid resuscitation, should be performed for patients with severe hemorrhage in obvious need of transfusion.
If blood products are not immediately available, we suggest that initial fluid resuscitation for trauma patients in hemorrhagic shock consist of 500 mL boluses of isotonic crystalloid given as rapidly as possible through short, large gauge (16 or larger) peripheral IVs. Central venous catheters are used when peripheral IVs are not available. Fluid resuscitation using such boluses continues until blood products are available or a systolic blood pressure (SBP) of 80 to 90 mmHg is achieved. However, if significant traumatic brain injury (TBI) or spinal injury is suspected, then the goal for resuscitation is a mean arterial pressure of 85 to 90 mmHg. (See 'Delayed fluid resuscitation/controlled hypotension' below and 'Spinal cord injury in the setting of hemorrhagic shock' below.)
One prospective observational study looking at goal directed resuscitation in the prehospital setting found that infusions of more than 500 mL of isotonic crystalloid were associated with worse outcomes in patients without hypotension (defined as a SBP <90), but not in patients with hypotension, suggesting that resuscitation should be goal directed based on the presence or absence of hypotension [15].
Harm can ensue in cases when excessive amounts of fluid are given to a patient at increased risk (eg, patient with coagulopathy of trauma or acute renal injury caused by hypoperfusion during a period of hemorrhagic shock). A retrospective study of just over 3000 trauma patients resuscitated with isotonic crystalloid found no negative effect in patients given 1 L of fluid or less but reported a two-fold increase in mortality among patients who received 1.5 L or more [14].
Type of fluid — The ideal resuscitation fluid for injured patients remains unclear. If intravenous fluids must be administered, we suggest using balanced crystalloids such as Lactated Ringer (LR) until blood products are available. Infusions of large volumes of isotonic (0.9%) saline (ie, normal saline [NS]) can lead to the development of a non-anion gap hyperchloremic metabolic acidosis. On the other hand, large volume resuscitation using LR can cause a metabolic alkalosis, as lactate metabolism generates bicarbonate. However, the typical volumes of either NS or LR used during a trauma resuscitation do not appear to have significant clinical consequences. The constituents of NS, LR, and other commonly used intravenous solutions are described in the following table (table 2). Of note, LR and blood must be infused through separate IV tubing because of the risk of clotting, which may be problematic in the setting of trauma.
Debate over the best approach to fluid resuscitation in traumatic shock is likely to continue. A systematic review of prehospital fluid resuscitation in trauma found insufficient evidence for the superiority of any particular fluid type [16]. Some researchers claim LR is superior to NS in the resuscitation of uncontrolled hemorrhagic shock, stating that patients who receive large volumes of NS experience increased blood loss and greater hypercoagulability; other researchers argue just the opposite [17,18]. A subsequent multicenter trial involving over 15,000 critically ill patients, including nontrauma and trauma patients, reported that those treated with balanced crystalloids (eg, LR) had lower mortality (10.3 versus 11.1 percent) and fewer major kidney injuries (14.3 versus 15.4 percent) compared with those who received NS [19]. Harm from either is highly unlikely if used in limited (2 L or less) amounts. The relative merits and use of different crystalloid solutions for resuscitation are discussed in detail separately. (See "Treatment of severe hypovolemia or hypovolemic shock in adults", section on 'Buffered crystalloid'.)
Hypertonic saline has been evaluated extensively, and may provide benefit through osmotic movement of interstitial fluid into the vascular compartment and modulation of the inflammatory response to injury [20]. While some clinical trials have shown improved outcomes [21], others have failed to do so, even in patients who would seem most likely to benefit (eg, patients with hypotension and severe TBI) [22,23]. Further study is needed to clarify the role of hypertonic saline.
The value of colloids (albumin solution, dextran) for resuscitation of traumatic shock is unproven [24,25]. Colloids effectively increase intravascular volume and may maintain plasma oncotic pressure at more normal levels compared with crystalloids. However, a systematic review of trials comparing resuscitation fluids found that use of colloids did not improve mortality or morbidity among trauma patients [25]. (See "Treatment of severe hypovolemia or hypovolemic shock in adults", section on 'Normal saline (crystalloid)'.)
Research continues into oxygen-carrying resuscitation fluids that can serve as alternatives to PRBCs. The ideal replacement fluid would transport oxygen effectively, expand intravascular volume, exhibit few or no side effects, and demonstrate great durability. Potential replacement fluids are discussed separately. (See "Oxygen carriers as alternatives to red blood cell transfusion".)
Delayed fluid resuscitation/controlled hypotension — A growing number of researchers describe aggressive intravenous fluid administration as ineffective and potentially harmful [12,14,26,27], and suggest that limited volume replacement intended to maintain minimally adequate organ perfusion may improve outcomes [28]. This strategy has been referred to as delayed fluid resuscitation, controlled hypotension, permissive hypotension, hypotensive resuscitation, or controlled resuscitation, all of which describe an approach that targets early intravenous fluid resuscitation only to a SBP of greater than 70 mmHg [29].
Controlled hypotension may be beneficial in patients with hemorrhagic shock due to torso injuries from gunshot or stab wounds. However, it may be detrimental to blunt trauma patients with brain injury, as hypotension reduces cerebral perfusion and increases mortality [30]. The rationale for improved outcomes with delayed fluid resuscitation is that aggressive fluid administration might, via augmentation of blood pressure, dilution of clotting factors, and production of hypothermia, disrupt thrombus formation and enhance bleeding [31,32]. European guidelines for the management of hemorrhaging trauma patients recommend maintaining a mean arterial pressure (MAP) of 50 to 60 mmHg in patients without brain injury [11].
Adoption of the strategy of delayed fluid resuscitation or controlled hypotension into clinical practice must be undertaken cautiously [33]. Factors that should be considered when determining whether this strategy is appropriate include the patient's mental status and likelihood of intracranial injury, likelihood of spinal cord injury (SCI), underlying illness such as chronic hypertension, and proximity to a trauma center. Further research to determine the appropriateness and effectiveness of this approach is needed [33]. Based on current data, limiting fluid resuscitation to 1 L or less and moving directly to blood products appears to be the best strategy. (See 'Transfusion of blood products' above.)
In one widely cited prospective study of 598 patients with penetrating chest injuries treated at a major trauma center, delayed fluid resuscitation until operative intervention to control bleeding was associated with a statistically significant improvement in patient survival (70 versus 62 percent in those given immediate fluid repletion) [34]. Care must be taken when extrapolating the results of this trial. Stratification was not performed to identify which patients might benefit from delayed therapy, subjects were primarily young and healthy, and the mean time from injury to operation was two hours, results that are not attainable in most circumstances.
In a preliminary analysis of a trial conducted at another major trauma center, 90 young adults with penetrating (n = 84) or blunt (n = 6) trauma resulting in at least one SBP reading below 90 mmHg, and hemorrhage requiring immediate laparotomy or thoracotomy, were randomly assigned upon arrival to the operating theater to resuscitation using a low-goal mean arterial pressure of 50 mmHg (LMAP group) or a high-goal mean arterial pressure of 65 mmHg (HMAP) [35]. Among the patients excluded were those with traumatic brain injury. Anesthesiologists did not intervene to lower the blood pressure of patients in the LMAP group whose MAP exceeded 50 mmHg. Patients in the LMAP group had lower postoperative mortality (6 versus 10 deaths), received fewer blood products (1594 versus 2898 mL), and did not develop coagulopathy or multiple organ failure (MOF), compared with seven cases of coagulopathy and two cases of MOF in the HMAP group. However, there was no significant difference between the groups in overall mortality at 30 days.
Other results favoring controlled hypotension or controlled resuscitation for both penetrating and blunt trauma patients include European guidelines published in 2019 recommending a target SBP of 80 to 90 mmHg until major bleeding has been stopped in the initial phase following trauma without brain injury [11]. Another randomized trial conducted by The Resuscitation Outcomes Consortium (ROC) published in 2015 concluded that controlled resuscitation (defined as SBP >70 mmHg) is achievable in out-of-hospital and hospital settings and may offer an early survival advantage in blunt trauma [36].
Reversal of anticoagulation — Some trauma patients, particularly older adults with comorbidities, may be taking anticoagulants. Provided below are several tables outlining methods for reversing particular anticoagulants in cases of life-threatening bleeding, as well as links to more detailed discussions of how to manage bleeding associated with these medications:
●Warfarin (see "Management of warfarin-associated bleeding or supratherapeutic INR", section on 'Serious/life-threatening bleeding'): Initial emergency treatment to reverse anticoagulation due to warfarin in patients with severe hemorrhage is outlined in the following table (table 3)
●Direct thrombin inhibitors (eg, dabigatran) and factor Xa inhibitors (eg, rivaroxaban, apixaban, edoxaban) (see "Management of bleeding in patients receiving direct oral anticoagulants"): Initial emergency treatment to reverse anticoagulation due to direct oral anticoagulants in patients with severe hemorrhage is outlined in the following table (table 4)
●Heparin (see "Heparin and LMW heparin: Dosing and adverse effects", section on 'Bleeding')
●Low molecular weight heparin (see "Heparin and LMW heparin: Dosing and adverse effects", section on 'Bleeding')
Vasopressors — No human studies exist to support the use of vasopressors in the resuscitation of the adult with multiple trauma [37]. Their use early in the management of hemorrhagic shock may be harmful [38]. Vasopressor therapy may be needed in the setting of neurogenic shock. (See "Acute traumatic spinal cord injury".)
MANAGEMENT BY CLINICAL SCENARIO
Predicting the need for massive transfusion — A massive transfusion protocol (MTP) should be in place for any hospital that manages trauma. This protocol should be activated in anticipation of the need for large-scale transfusion or as soon as the clinician treating the patient recognizes the presence or likelihood of severe, ongoing hemorrhage. (See "Massive blood transfusion".)
Determining when to initiate an MTP has been the subject of considerable research [39]. As early implementation of massive transfusion in the appropriate patient improves outcomes, identifying those trauma patients early in their ED course is important [40]. While a number of scores have been developed for this purpose, the Assessment of Blood Consumption (ABC) score has been validated and is easy to use [41,42]. The ABC score relies on 4 parameters that can be determined upon arrival to the ED:
●Penetrating mechanism of injury
●Positive FAST (Focused Assessment with Sonography in Trauma) examination (ie, evidence of hemorrhage)
●SBP of 90 mmHg or less
●Heart rate of 120 beats per minute (bpm) or greater
Each positive parameter receives a score of one. A score of 2 or more predicts the need for massive transfusion with a sensitivity of 75 percent and a specificity of 86 percent.
If ultrasound is not available, another study group uses a "Code Red" determination by prehospital physicians to request that massive transfusion resources be available upon arrival to the ED. The designation is based on three parameters: suspicion or evidence of active bleeding, SBP less than 90 mmHg, and lack of a blood pressure response to an IV fluid bolus. Ninety-one percent of patients meeting any of these criteria ended up receiving blood products, and 40 percent of those went on to require a massive transfusion [43].
Other scores have been described, including the Trauma-Associated Severe Hemorrhage (TASH) score, Emergency Transfusion Score (ETS), and the Prince of Wales Hospital (PWH) score [44-46]. The score selected is likely less important than having a score that all clinicians understand and agree to use.
Traditionally, a massive transfusion was considered 10 units of PRBCs or more transfused over a 24-hour period, but many experts now advocate a revised definition of 10 units or more transfused over six hours [40]. We prefer the assessment tools described immediately above.
Severe ongoing hemorrhage — For trauma patients with severe, ongoing hemorrhage that is unlikely to be controlled quickly or adequately, we suggest immediate transfusion of blood products in a 1:1:1 ratio of PRBCs, fresh frozen plasma (FFP), and platelets. Whole blood is a reasonable alternative if available. The hospital's massive transfusion protocol (MTP) should be activated immediately in such circumstances. (See 'Predicting the need for massive transfusion' above.)
In other words, as soon as the treating clinician recognizes that the patient will require 4 or more units of PRBCs over one hour (or 10 or more units over 6 hours), he or she should begin transfusing 6 units of PRBCs, 6 units of FFP, and 6 units of random donor platelets (or 1 unit of apheresis platelets). Note that 1 unit of apheresis platelets is equivalent to 6 units of non-apheresis (ie, random donor or whole-blood derived) platelets. Evidence to support this approach of transfusing components in a 1:1:1 ratio is presented separately. (See "Massive blood transfusion", section on 'Trauma'.)
Hypothermia must be prevented during transfusions. Interventions to accomplish this include keeping the trauma bay warm, warming fluids and blood products to be transfused, and covering the patient with warm blankets to the extent possible. Where available, thromboelastography (TEG) and rotational thromboelastometry (ROTEM) provide faster and more accurate assessment of coagulopathy in the trauma patient, and can help guide ongoing treatment with clotting factors as well as reduce unnecessary transfusion. (See "Coagulopathy in trauma patients".)
Excessive infusion of crystalloid (ie, ratio of crystalloid to PRBCs >1.5:1) can contribute to hypothermia, has been associated with worse outcomes in patients with severe hemorrhage, and should be avoided. (See 'Intravenous fluid resuscitation' above.)
Patient within three hours of injury — In patients with signs of significant, active hemorrhage who present within three hours of injury, we suggest administering tranexamic acid (TXA). Significant trauma results in a marked inhibition of fibrinolysis; TXA is an antifibrinolytic agent that reduces all-cause and bleeding-related mortality if given within three hours of injury in patients with significant hemorrhage. Where available, thromboelastography (TEG) can be used to guide treatment, but if TEG is unavailable, we advocate empiric treatment with TXA except for patients with isolated, severe traumatic brain injury (TBI). The initial dose is 1 gram given over 10 minutes. The evidence supporting TXA, its use in general trauma, and its use in brain injury are discussed separately. (See "Coagulopathy in trauma patients", section on 'Management of fibrinolysis' and "Management of acute moderate and severe traumatic brain injury", section on 'Initial evaluation and treatment'.)
Moderate ongoing hemorrhage — For patients with bleeding that is not severe but is ongoing and significant (eg, more than 4 units of PRBCs are transfused in the first few hours, or chest tube continues to drain >200 mL of blood per hour), we suggest using the same transfusion ratios used for patients with severe hemorrhage: a 1:1:1 ratio of PRBCs, FFP, and random donor platelets. If apheresis platelets are used, this becomes a 6:6:1 ratio of PRBCs, FFP, and apheresis platelets respectively. (See 'Severe ongoing hemorrhage' above.)
Hypothermia must be prevented during transfusions. Where available, thromboelastography (TEG) and rotational thromboelastometry (ROTEM) provide faster and more accurate assessment of coagulopathy in the trauma patient, and can help guide ongoing treatment with clotting factors as well as reduce unnecessary transfusion [47]. (See "Coagulopathy in trauma patients".)
Bleeding readily controlled in ED — Severe bleeding can sometimes be controlled effectively in the ED or trauma bay. Closure of scalp lacerations and compression of venous extremity wounds reduce the threat of further bleeding, even though significant hemorrhage may have occurred. Application of a tourniquet can prevent further bleeding from what would otherwise be a life-threatening extremity wound.
Whether to transfuse after bleeding has been controlled depends on the clinical situation and the patient's underlying comorbidities. Patients that are experiencing symptoms due to anemia from blood loss may require transfusion even after bleeding has been controlled. As an example, a patient with coronary artery disease who is experiencing chest pain suggestive of an acute coronary syndrome should be given blood. The hemoglobin thresholds for patients with comorbidities are discussed separately and summarized in the following table (table 5). (See "Indications and hemoglobin thresholds for red blood cell transfusion in the adult".)
There is no evidence of benefit from transfusing patients in whom bleeding has been controlled and who are not experiencing any symptoms related to anemia. Therefore, we do not recommend transfusion in this situation.
Fluid resuscitation and blood transfusion for the transfer patient — Clinicians transferring trauma patients for definitive care must determine what fluids or blood products to send with the patient. The answer depends on the clinical scenario, including the extent of known or suspected injuries, the blood products available, and the capabilities of the transport team.
Sometimes it is necessary to transfer a patient being actively resuscitated for as yet unknown injuries. In these situations, we recommend limiting the administration of crystalloid prior to transfer (in part to prevent infusions of large volumes during transfer), and emphasizing transfusion of blood products in a 1:1:1 ratio whenever possible. We exceed two liters of crystalloid only if blood products are not available. If only one blood product can accompany the patient during transfer, PRBCs should be taken, bearing in mind the ultimate goal of giving a 1:1:1 ratio of blood products [48]. Prior to arrival at a trauma center where definitive management of the bleeding can take place, a goal of SBP >80 with a MAP of 65 mmHg for penetrating trauma, and a MAP of 85 mmHg for blunt trauma with possible head injury is appropriate.
Patients with SCI and hemorrhagic shock who are being transferred should be sent with both blood products and norepinephrine, assuming each is available, and managed using the same approach: give blood products first and add the vasopressor if MAP goals are not achieved. (See 'Spinal cord injury in the setting of hemorrhagic shock' below.)
Spinal cord injury in the setting of hemorrhagic shock — Patients with a spinal cord injury (SCI) who are in hemorrhagic shock pose a special challenge. While controlled hypotension may be appropriate for many trauma patients, those with SCI, like those with TBI, are at greater risk for complications from hypotension. Thus, a higher blood pressure is needed to ensure adequate perfusion of the spinal cord. Guidelines from 2013 recommend maintaining a MAP of at least 85 to 90 mmHg for patients with SCI [49], and subsequent studies support this goal [50]. Acute SCI and the management of TBI are discussed separately. (See "Management of acute moderate and severe traumatic brain injury" and "Acute traumatic spinal cord injury".)
In the uncommon circumstance when hemorrhagic shock and SCI coexist, the most immediate life threat is blood loss. Therefore, transfusion of blood products is prioritized. However, long-term morbidity in such patients depends largely upon the ability to maintain MAP in the goal range. Thus, vasopressor therapy should be added expeditiously if an appropriate MAP cannot be achieved with blood products alone. (See "Use of vasopressors and inotropes".)
For patients with SCI and hemorrhagic shock, we recommend transfusing blood as described above for patients with severe ongoing bleeding, with the goal of maintaining a MAP of 85 to 90 mmHg. Vasopressor therapy is needed for patients with SCI when blood products alone have failed to raise or maintain the MAP in the 85 to 90 mmHg range. While there are no data to support a particular timeline, given the critical importance of maintaining perfusion in patients with TBI or SCI, we suggest initiating vasopressor therapy within 15 minutes of blood product resuscitation if a MAP of 85 has not been achieved. While there is no clearly defined combination of blood products and vasopressor treatment for these patients, norepinephrine is recommended over dopamine or phenylephrine by some authorities when vasopressors are required for patients with SCI, and we concur with this approach [51].
Patients with SCI and hemorrhagic shock who are being transferred should be sent with both blood products and norepinephrine, assuming each is available, and managed using the same approach: give blood products first and add the vasopressor if MAP goals are not achieved.
Geriatric patient with hemorrhage — The indications for and general approach to fluid resuscitation and blood transfusion do not differ in the older adult trauma patient. Evaluation and management of these patient are reviewed in detail separately. (See "Geriatric trauma: Initial evaluation and management".)
Important considerations related to hemorrhage in the older adult trauma patient include:
●Vital signs in older adults can be difficult to interpret and make the recognition of hemorrhagic shock more difficult (eg, baseline hypertension, effects of medications – beta blockers) (See "Geriatric trauma: Initial evaluation and management", section on 'Assessment and initial interventions'.)
●Preexisting conditions such as ischemic heart disease, heart failure, or renal dysfunction can cause older adult patients to decompensate from excessive IV fluid administration or blood loss.
●A relatively large percentage of older adults take oral anticoagulants and are at increased risk for immediate or delayed hemorrhage. (See "Geriatric trauma: Initial evaluation and management", section on 'Patients taking anticoagulants'.)
●Early transfusion is appropriate for the initial treatment of hypotension or signs of hypoperfusion.
Pregnant patient with hemorrhage — The indications for and general approach to fluid resuscitation and blood transfusion do not differ in the pregnant trauma patient. Evaluation and management of the pregnant trauma patient are reviewed in detail separately. (See "Initial evaluation and management of major trauma in pregnancy".)
Important considerations related to hemorrhage in the pregnant patient include:
●Rapid obstetrical consultation should be obtained in case cesarean delivery is needed.
●Displacing the uterus to the patient's left side may significantly improve cardiac output.
●Substantial changes in vital signs may not occur until more than 20 percent of total blood volume has been lost due to the hypervolemia and normal physiology of pregnancy.
●Continuous fetal heart rate monitoring, when appropriate based on viability (>20 weeks gestation), is essential for determining the condition of the fetus.
●Treatment with anti-D immune globulin may be needed. RhD-negative women with abdominal or pelvic trauma or with vaginal bleeding (who are not already alloimmunized, if this is known) should receive anti-D immune globulin, per standard protocols.
MONITORING AND GOALS FOR PROLONGED RESUSCITATION
Patients with severe bleeding — Clear resuscitation goals for the early management of adult trauma patients remain undefined [52]. Thromboelastography (TEG), or comparable rapid point-of-care assessment of coagulation, should be used to guide blood transfusion whenever available. However, in many community hospitals, such resources are not available. In such cases, a mean arterial pressure (MAP) around 65 mmHg or a systolic blood pressure (SBP) of 80 to 90 mmHg is a reasonable goal for patients with penetrating trauma. For blunt trauma patients, particularly those with possible traumatic brain injury (TBI) or spinal cord injury (SCI), a MAP above 85 mmHg or a SBP above 120 mmHg is reasonable. These goals may need to be adjusted upward in patients with a known history of uncontrolled hypertension. (See 'Management by clinical scenario' above and "Coagulopathy in trauma patients".)
Most experts advocate strictly limiting the amount of IV fluid used for trauma resuscitation in the absence of hypotension or obvious injury [53]. Early blood transfusion is preferred to continued administration of IV fluids. In addition to the potentially harmful effects of excess IV fluid on coagulation and blood counts, patients with heart failure, pulmonary hypertension, and other conditions sensitive to rapid increases in intravascular volume may decompensate from such resuscitation. Careful, continual monitoring of these patients is crucial.
Some trauma patients, particularly in community hospitals, must be managed in the emergency department (ED) for prolonged periods when surgical resources or transport is not immediately available. It remains unclear what resuscitation targets are most useful for guiding management. Those emergency clinicians without access to sophisticated noninvasive technologies such as TEG must rely on standard physiologic and laboratory measurements to determine whether resuscitation is adequate. An approach modeled on goal-directed therapy for septic shock, with the important caveat that greater emphasis be placed on blood transfusion and coagulation factor replacement, may be helpful [54].
The following parameters may be used to guide prolonged resuscitation of traumatic shock [54,55]:
●Blood pressure: Maintain MAP above 65 mmHg for penetrating trauma, and above 85 mmHg for blunt trauma that may involve TBI or SCI.
●Heart rate (HR): Maintain between 60 and 100 beats per minute. Keep in mind that a HR in this range may be abnormal for some patients, such as a healthy young adult with a resting HR of 50 who presents with a HR of 90 following trauma.
●Oxygen saturation: Maintain above 94 percent.
●Urine output: Maintain above 0.5 mL/kg per hour.
●Lactate and base deficit: Monitor serum lactate and serum bicarbonate every four hours to ensure end-organ perfusion is adequate or improving with resuscitation. Reasonable goals of resuscitation include a serum lactate <2 mmol/L and normalization of any base deficit.
●Mixed central venous oxygen saturation: Monitor every four hours to ensure end-organ perfusion is adequate or improving with resuscitation; goal is to maintain above 70 percent.
If bleeding is massive and ongoing, laboratory measurements can be inaccurate. Empiric guidelines for transfusion of blood products in this setting are provided above. With such patients, rapid control of the source of bleeding is paramount. (See 'Severe ongoing hemorrhage' above.)
Some researchers advocate using the lactate concentration to assess the adequacy of resuscitation [56-58]. Lactate levels may lag behind clinical improvement following aggressive resuscitation if rapid analyzers are unavailable. Other authors suggest that the magnitude of metabolic acidosis has prognostic value [59] and that the admission base deficit (ie, serum bicarbonate) may be superior to plasma lactate in predicting injury severity and death [60]. Both endpoints may provide useful feedback about tissue oxygen debt and the adequacy of resuscitation [61,62].
Studies have compared noninvasive and invasive (eg, pulmonary artery catheter) monitoring started in the ED for resuscitation of critical trauma patients. Enhanced noninvasive monitoring appears to be feasible, safe, inexpensive, and equivalent to invasive monitoring [54,63]. Noninvasive monitoring in these studies included such technologies as thoracic electrical bioimpedance, esophageal Doppler monitoring, and orthogonal spectral imaging, in addition to standard measures, such as MAP, heart rate, pulse oximetry, and carbon dioxide tension. Many emergency clinicians do not have access to these technologies, and their role in ED management of trauma awaits further study.
Patients without severe bleeding — The following guidelines may be used for transfusion of blood products in trauma patients without severe bleeding:
●Hemoglobin: Transfuse 2 units PRBCs if hemoglobin falls below 8 g/dL (80 g/L) for patients without risk for acute coronary syndrome (ACS), or below 10 g/dL (100 g/L) for patients at risk for ACS [64].
●Platelets: Transfuse 1 unit of apheresis platelets, or 6 units of random donor platelets, if the serum concentration falls below 50,000/microL.
●International normalized ratio (INR): Transfuse 2 units of FFP if INR rises above 2.
●Fibrinogen: Transfuse 10 units of cryoprecipitate if the fibrinogen concentration falls below 100 mg/dL (3 micromol/L).
DISPOSITION — Definitive management of the patient with traumatic shock often requires emergency surgery. Emergency clinicians should consult a trauma surgeon as soon as possible for all victims of significant trauma who may require operative or critical care interventions.
If the patient must be transferred for definitive care, early communication with a trauma center and preparation for transfer is performed concurrently with assessment and stabilization. The lack of adequate resources to manage a patient's injuries, including specialty and subspecialty care, is an indication for transfer to a trauma center. Radiology studies in patients to be transferred should be kept to a minimum and focus only on identifying pathology that the transferring center is capable of addressing. Transfer must not be delayed to perform radiology or laboratory studies that cannot be acted on prior to transfer.
Patients with SCI and hemorrhagic shock who are being transferred should be sent with both blood products and norepinephrine, assuming each is available, and managed using the same approach: give blood products first and add the vasopressor if MAP goals are not achieved.
In cases involving a hypotensive patient with an identified injury (eg, high-grade splenic laceration), but no trauma surgeon is available, immediate consultation with a general surgeon may be necessary for possible laparotomy prior to a time-consuming transfer that would put the patient at risk.
DEVELOPING TREATMENTS FOR HEMORRHAGE
Hemostatic agents — In some circumstances, external hemorrhage cannot be controlled using direct pressure and standard dressings. A number of hemostatic products are being developed to control such bleeding, including chitosan dressing, Kaolin-impregnated sponge, and fibrin sealant dressing (table 6). Although a number of these products have been used by military personnel in combat, few controlled studies with civilians have been performed and it remains unclear how these products should be used by civilian emergency clinicians. These agents are discussed separately. (See "Overview of topical hemostatic agents and tissue adhesives", section on 'External agents'.)
Antifibrinolytic agents — Several antifibrinolytic agents (ie, tranexamic acid [TXA], aminocaproic acid, aprotinin) have been shown to be safe and effective at reducing bleeding during elective surgery and in other bleeding disorders. Significant trauma results in a marked inhibition of fibrinolysis, and TXA has gained acceptance for use in trauma patients and is discussed above and separately. An overview of these agents is provided separately. (See 'Patient within three hours of injury' above and "Thrombotic and hemorrhagic disorders due to abnormal fibrinolysis", section on 'Therapies for hyperfibrinolytic states' and "Coagulopathy in trauma patients", section on 'Pharmaceutical hemostatic agents'.)
Recombinant factor VIIa — The use of recombinant factor VIIa (Factor VIIa) in trauma is off-label and discussed separately. (See "Recombinant factor VIIa: Administration and adverse effects", section on 'Trauma or surgery'.)
Red blood cell substitutes — Research continues into oxygen-carrying resuscitation fluids that can serve as alternatives to packed red blood cells. The ideal replacement fluid would transport oxygen effectively, expand intravascular volume, exhibit few or no side effects, and demonstrate great durability. Potential substitutes (eg, hemoglobin-based oxygen carriers, perfluorocarbons) continue to be studied in both animal and human trials. This subject is discussed separately. (See "Oxygen carriers as alternatives to red blood cell transfusion", section on 'Surgery'.)
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: General issues of trauma management in adults".)
INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5th to 6th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10th to 12th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.
Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)
●Basics topic (see "Patient education: Shock (The Basics)")
SUMMARY AND RECOMMENDATIONS
●Classification of hemorrhage – Hemorrhagic shock comprises the majority of cases of traumatic shock and is commonly divided into four classes based on clinical presentation. Significant drops in blood pressure are generally not manifested until Class III hemorrhage develops, and up to 30 percent of a patient's blood volume can be lost before this occurs. Individual patients with severe injuries, including the young and healthy and the older adult taking cardiovascular medications, may not manifest obvious signs of shock initially. Careful assessment and reassessment of patients involved in significant trauma is crucial. (See 'Classification of hemorrhage' above and "Initial management of trauma in adults" and "Approach to shock in the adult trauma patient".)
●Sites of hemorrhage – Massive hemorrhage can occur in the chest, abdomen, retroperitoneum, and from major external wounds. The thigh can hold up to approximately 1 L of blood. Scalp lacerations can bleed profusely and are often overlooked. Non-hemorrhagic causes of traumatic shock are discussed separately, and a detailed list is provided (table 1). (See 'Initial assessment and interventions' above and "Approach to shock in the adult trauma patient".)
●Overview of management – The management of hemorrhage in the adult trauma patient will vary depending upon the known or suspected injuries, vital signs, extent of hemorrhage, available resources, and need for transfer. Key principles for the management of hemorrhage due to trauma include the following (see 'Resuscitation and transfusion' above):
•Minimize the use of intravenous fluids for resuscitation. Use them only for hypotensive patients, and then only until blood is available. (See 'Intravenous fluid resuscitation' above.)
•Transfuse blood products as soon as the need is recognized. (See 'Transfusion of blood products' above.)
•Give blood products (ie, red blood cells, plasma [clotting factors], and platelets) in equivalent amounts (1:1:1 ratio). Whole blood can be given if available.
•Rapidly mobilize all needed resources (eg, surgery, anesthesia, blood bank, transfer to trauma center).
•Use thromboelastography, or comparable rapid point-of-care assessment of coagulation, to guide trauma resuscitation whenever available. (See "Coagulopathy in trauma patients".)
A favorable initial response to volume replacement or blood transfusion does not rule out severe, occult injury. Effective early resuscitation may mask ongoing significant hemorrhage. The presence of one injury does not exclude the possibility of other, more serious injuries.
●Intravenous (IV) fluid resuscitation – If IV fluids must be administered, use balanced crystalloids such as Lactated Ringer (LR) until blood products are available. Limit the total volume of fluid administered to under 1 liter of crystalloid if blood products are available. (See 'Intravenous fluid resuscitation' above.)
●Massive blood product transfusion – For trauma patients with severe, ongoing hemorrhage that is unlikely to be controlled quickly or adequately, start immediate transfusion of blood products in a 1:1:1 ratio of packed red blood cells (PRBCs), fresh frozen plasma (FFP), and platelets. The supporting evidence for this ratio of blood products is provided elsewhere (see "Massive blood transfusion", section on 'Trauma').
Appropriate quantities of either random donor or apheresis platelets may be used (6 units of random donor platelets equals 1 unit of apheresis platelets). (See 'Severe ongoing hemorrhage' above.)
Hospitals that care for trauma patients should develop a massive transfusion protocol. (See 'Predicting the need for massive transfusion' above.)
●Supportive care during transfusion – In trauma patients with severe hemorrhage who are receiving blood transfusions, additional elements of care include preventing hypothermia and avoiding all unnecessary infusions of fluids other than blood products. (See 'Severe ongoing hemorrhage' above and 'Intravenous fluid resuscitation' above.)
●Tranexamic acid (TXA) – In patients with signs of significant, active hemorrhage who present within three hours of injury, we administer TXA. The initial dose is 1 gram given over 10 minutes. Where available, thromboelastography (TEG) can be used to guide treatment, but if TEG is unavailable, we advocate empiric treatment with TXA except in patients with isolated, severe traumatic brain injury (TBI). The evidence supporting the use TXA is presented elsewhere. (See 'Patient within three hours of injury' above and "Coagulopathy in trauma patients", section on 'Management of fibrinolysis'.)
●Goals in patients with severe bleeding – TEG, or comparable rapid point-of-care assessment of coagulation, should be used to guide blood transfusion whenever available. When unavailable, a mean arterial pressure (MAP) around 65 mmHg or a systolic blood pressure (SBP) of 80 to 90 mmHg is a reasonable goal for patients with penetrating trauma. For blunt trauma patients, particularly those with possible traumatic brain injury (TBI) or spinal cord injury (SCI), a MAP above 85 mmHg or an SBP above 120 mmHg is reasonable. (See 'Monitoring and goals for prolonged resuscitation' above.)
●Management of clinical scenarios – Scenarios other than severe ongoing hemorrhage include the following:
•Moderate ongoing hemorrhage – Use the same transfusion ratios used for patients with severe hemorrhage: a 1:1:1 ratio of PRBCs, FFP, and random donor platelets. If apheresis platelets are used, this becomes a 6:6:1 ratio of PRBCs, FFP, and apheresis platelets, respectively. (See 'Moderate ongoing hemorrhage' above.)
•Readily controlled hemorrhage – Patients that are experiencing symptoms due to anemia from blood loss may require transfusion even after bleeding has been controlled. There is no evidence of benefit from transfusing patients in whom bleeding has been controlled and who are not experiencing any symptoms related to anemia. (See 'Bleeding readily controlled in ED' above.)
•Hemorrhage in patient requiring transfer – In a patient who needs transfer with an unidentified injury, limit the administration of crystalloid prior to transfer and transfuse blood products in a 1:1:1 ratio whenever possible. We exceed 1 liter of crystalloid only if blood products are not available. If only one blood product can accompany the patient during transfer, PRBCs should be taken. (See 'Fluid resuscitation and blood transfusion for the transfer patient' above.)
•Spinal cord injury and hemorrhage – These patients are at greater risk for complications from hypotension, and a higher blood pressure is needed to ensure adequate perfusion of the spinal cord (maintain a MAP of at least 85 to 90 mmHg). (See 'Spinal cord injury in the setting of hemorrhagic shock' above.)
•Pregnant patient with hemorrhage – Important considerations include rapid obstetrical consultation, displacing the uterus to the patient's left side, recognizing that substantial changes in vital signs may not occur until more than 20 percent of total blood volume has been lost, need for continuous fetal heart rate monitoring, and treat with anti-D immune globulin when needed. (See 'Pregnant patient with hemorrhage' above.)
