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K. Matsushima and H. Frankel

arrival to a facility that will provide denitive care and can have a negative impact on survival. In general, the “scoop and run” paradigm should remain the rule and not be the exception for penetrating trauma. While stabilizing procedures should be undertaken before and during transport, any monitoring or intervention (“stay and play”) that delays denitive treatment of penetrating injury—often an operation—is generally unhelpful.

6.1.2 Mode ofTransportation

In most circumstances, the appropriate mode of transportation for penetrating injury patients in an urban environment is via ground ambulance. The benet of advanced life support (ALS) units may be questioned as noted above; however, most protocols call for this additional level of expertise “just in case.” Use of whichever means that gets the patient to the trauma center the soonest is optimal. Ambulance units should strive to keep the on-scene duration to 10min or less to adhere to guidelines outlined by PHTLS.Depending on each particular region, the ground ambulance personnel who provide ALS may have similar interventional skills to that of the air transport crews, but knowledge and evaluation of local resources are necessary. Helicopter transport in urban settings is best utilized when the air transport time will be less than that of a ground ambulance. Within approximately 30 miles, ground transport is typically as fast as air when over favorable terrain in no trafc settings. Helicopter transport often ies in any inclement weather, including overcast skies with low ceilings.

6.1.3 Initial Assessment ofthePatient byEMS

Wound location and hemodynamic information should be communicated in a concise report before arrival to the trauma center to deliver appropriate subsequent patient care. Initially, the injured patient should undergo assessment and management in an orderly, logical manner in a head-to-toe fashion. A patient with obvious penetrating trauma to the anterior torso can easily have a missed injury to the gluteal region if a careful inspection of all clothed areas is not performed. Such a missed injury can cause signicant additional hemorrhage that may have been easily ameliorated by direct pressure. Currently, few available devices offer diagnostic improvement over a thorough physical examination, including inspection, auscultation, percussion, and palpation by a well-trained medical provider. Additionally, data obtained from such additional devices must be veried as well, whether or not it is in a normal range.

6.1.4 Wound Assessment

When passing the patients over to the trauma team, there are three main pieces of information regarding the wound that needs to be conveyed. First, the trauma team needs to know the location of the wound(s) to plan further diagnostic and therapeutic maneuvers. Because the nal destination of the missile or knifepoint may not be known from the external wound, it is key that EMS personnel do not refer to wounds as affecting the “chest,” “abdomen,” or “back.” A wound at the sixth left intercostal space in the anterior axillary line may, in fact, involve abdominal structures and require a laparotomy for denitive treatment. Referring to it as a “chest” wound may set different expectations for the receiving trauma team. Similarly a “back” wound may involve chest or abdominal structures with different diagnostic and therapeutic maneuvers required. Although the receiving team should recognize that rapid assessment on the spot may be awed, particularly if the scene is not secured, it is often helpful to have identied all wounds prehospital. It is important not to assume which wound is an entrance/exit wound or infer trajectories of the bullet in the eld. Next, by conveying hemodynamic information as described below, prehospital providers can allow the trauma team to infer whether an immediate operative intervention is warranted. This may result in alternate triage (i.e., some trauma centers might transport directly to the operating theater), activation of massive transfusion protocols, or release of other resources. Finally, by conveying information on wound location and hemodynamics in concert, the receiving trauma team may get a sense of what kind of operation is warranted.

Direct manual pressure and/or packing should be immediately applied to any active bleeding from external wounds. Further, recent studies from civilian experience support the use of prehospital tourniquet in patients with extremity vascular trauma. Tourniquets should be properly placed proximal to the bleeding site. The second tourniquet can be applied if the rst tourniquet did not effectively control hemorrhage. The initial tourniquet time needs to be documented to prevent serious complications including prolonged limb ischemia or compartment syndrome. There are different types of topical hemostatic agents commercially available for external bleeding in areas where tourniquets cannot be applied (e.g. groin, neck). These agents are usually in gauze or bandage format to be applied with pressure techniques.

6.1.5 Hemodynamic Assessment

Prehospital hemodynamic assessment utilizes the rapid “ABC” approach of airway, breathing, and circulation adequacy determination. The airway should be examined while maintaining cervical spine stabilization and moni-

6 Prehospital Monitoring During Transport

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tored for blockage with gurgling from vomitus, blood, or foreign body.

Breathing and ventilation are monitored by signs of full, symmetric chest wall movement, without crepitus or paradoxical motion. The patient should have a midline trachea with a normal respiratory rate and depth. A tension pneumothorax is a life-threatening condition that can be a cause of preventable death. Hyperresonance with percussion of the thoracic cavity and diminished breath sounds, especially in the face of a suspicious wound, are indications of pneumothorax. Increased air pressure between lung parenchyma and parietal pleural in the thoracic cavity reduces venous return and causes tachypnea, dyspnea, air hunger, and eventual cardiovascular collapse. Tracheal deviation, hypotension, and distended neck veins are all late hallmarks. Diagnosis is often established by therapeutic decompression as described below.

Patients are also monitored for their circulation status with appropriate hemorrhage control. Signs of hemorrhagic shock include diaphoresis, cool clammy skin with peripheral vasoconstriction, and diminished peripheral pulses. Capillary rell may be normal or delayed. Systemic hypotension may be seen late or only with profound shock. Hemodynamic status can be evaluated by the presence and character of the radial pulse when other reliable methods are not available. Manual assessment of a weak but present radial pulse correlates with a systolic blood pressure (SBP) of approximately 80mmHg, but studies have shown that estimates of SBP tend to overestimate the actual pressure. Unfortunately, changes in the pulse examination, blood pressure, and mental status are all late signs of central hypovolemia and do not provide adequate warning of impending circulatory collapse. Both radial pulses should be initially compared, as the occasional patient will have an asymmetric arm blood pressure in the pre-injured state from a subclavian artery stenosis, old injury, or atheroscleromatous plaque. The arm with the higher pressure should then be used for monitoring systemic blood pressure and circulation.

6.1.6 Monitoring andResuscitation En Route

The ACS-COT, in conjunction with the American College of Emergency Physicians and the National Association of EMS Physicians, has published a pamphlet recommending certain equipment deemed essential on an ambulance unit. In general, the degree and level of monitoring should be individualized based on the availability of resources and training of individual municipalities. For example, if ALS is to be provided, then pulse oximetry, end-tidal CO2 (EtCO2) detection, along with electrocardiography, a debrillator, and external cardiac pacemaker should be available. However, care must be taken not to delay transport beyond the benet received

by the intervention. It is up to the individual emergency medical director and local governing bodies to determine the practice guidelines to which the trauma system will adhere.

Patients with penetrating trauma should be transported to a trauma center on a standardized ambulance unit, optimally that provides ALS.Most units in urban and suburban areas provide ALS units that have the previously listed devices, as well as a thermometer and a sphygmomanometer. Other than standard vital signs and maintaining the ABCs of trauma care, there is a paucity of other useful prehospital monitoring currently utilized. Signs of internal hemorrhaging from a positive abdominal ultrasound, for example, may alert one of a potential need to stop at a closer trauma center, but with penetrating trauma to the trunk, one assumes those injuries are present until proven otherwise.

Attention is given to addressing frequent causes of preventable penetrating trauma deaths, which are loss of airway control, tension pneumothorax, and exsanguination from extremity vascular injuries. Monitoring principles should address these areas that are the foundations of ATLS and PHTLS, notably the ABCs airway, breathing, and circulation. Although electronics and mechanical devices aid in monitoring the status of the patient during transport, the time-honed skills of an experienced provider using inspection, auscultation, percussion, and palpation are also invaluable. Specic monitoring can be organized by the familiar sequence of the ABCs of trauma care taught in many educational courses.

Initial assessment of the trauma patient requires the establishment of a functional airway as the paramount priority. Pulse oximetry and EtCO2 detectors, either qualitative or quantitative, are recommended for ambulance units that provide ALS.Using infrared spectroscopy, quantitative detectors give an instantaneous numeric CO2 value. In contrast, easily portable colorimetric devices change color in response to the presence of airway CO2, but are unable to indicate hypo- or hypercarbia, and may falsely indicate loss of the airway by a low EtCO2 in response to certain physiological conditions. While the quantitative EtCO2 monitor can give feedback to prevent hypocapnia from vigorous ventilation in an intubated patient with traumatic brain injuries, the EtCO2 detector is adequate for transportation of short duration and conrms tube placement in the airway. Constant surveillance should be maintained, as even a secured airway may be lost during the transport. A high degree of suspicion is required, and any change in the patient’s condition necessitates reassessing from the beginning. If an endotracheal tube is inserted, condensation forming with each breath often conrms the correct placement across the larynx. With a difcult endotracheal intubation, two or three failed attempts should be the cause for reevaluation to see if other methods can be used to secure the airway, such as bag valve mask, laryngeal mask airway, or surgical airway. There exists much variability

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K. Matsushima and H. Frankel

in the success rate of attempted prehospital intubation, ranging from approximately one-third to two-thirds. One of the primary reasons for a failed attempt at endotracheal intubation is trismus or clenched jaw. While rapid sequence intubation (RSI) may increase the success rate in these particular patients, one only has to observe anesthesia providers in the operating room occasionally having difculty even under controlled, optimal circumstances to realize that an ambulance crew with only sporadic exposure to a patient who needs airway control may have serious hardships. When poor suctioning, mouth debris, facial trauma, and other complications are present, it is no wonder that securing an airway may be the most important responsibility and difcult-toachieve goal of ambulance providers. Thus, it remains unclear whether the airway should always be secured with endotracheal intubation particularly in urban prehospital setting where transport time is usually short. There is a nationwide variability in the rate of out-of-hospital endotracheal intubation after trauma. Similarly, contradictory results have been reported regarding the impact of prehospital intubation on the outcome of patients with traumatic brain injury.

If a tension pneumothorax is suspected, needle decompression with a long, large bore needle is performed in the second intercostal space at the midclavicular line or in the fourth or fth intercostal space at the midaxillary line. A rush of air upon entrance of the thoracic cavity conrms the diagnosis. ALS provides training to emergency medical technicians in proper placement of decompressive needle thoracostomy. Chest tube thoracostomy requires a higher level of training and skill and often is a cause of struggling in even junior level residents in a controlled emergency department setting.

Management of circulating blood volume relies on limiting the blood loss and restoration to maintain an adequate organ perfusion. Standard vital signs are often poor indicators of subtle changes or of early shock. Permissive hypotension is a strategy that aims to limit the amount of uid resuscitation until denitive hemorrhage control is performed. Most body organs can maintain viability with this level of perfusion, although patients with traumatic brain injuries may have a worse outcome using this approach.

6.1.7 Where toTransport Patients

As outlined by the triage decision scheme from the ACSCOT, all penetrating trauma should be taken to a trauma center, with possible exception of penetrating extremity wounds distal to elbows and knees. Care should be taken to assess the presence of any special needs when determining which appropriate facility will receive the patient, such as the abil-

ity of the facility to provide neurosurgical, obstetrical, neonatal, or cardiovascular care.

Triage requires evaluation of a patient to determine the appropriate facility to which the patient should be transferred. The ACS designates facilities from Level I to Level IV trauma centers. While Level I centers are often afliated with a university program and provide the highest level of dedicated resources, a Level II trauma center is expected to provide initial denitive trauma care for injuries of all severities. In a patient with exsanguinating torso injuries, seconds matter and having an experienced provider immediately available can only be expected to improve outcome. A Level III center provides resuscitation, emergency operations, and stabilization. A general surgeon is required to be available at Levels I, II, and III trauma centers. Specic patient needs should be evaluated when determining which facility would capable of managing the patient, such as injuries requiring neurosurgical, cardiovascular, neonatal, or pediatric intensive care.

6.2 Rural Environment

6.2.1 How andwhere toTransport

For rural trauma care, a Level IV facility may not be an institution that provides denitive surgical interventions or critical care. Air transportation may expedite delivery to denitive care at higher level trauma centers. The Field Triage Decision Scheme was created in 1986 and serves as a reference for developing triage protocols for EMS systems.

6.2.2 Additional Resuscitative Measures

toConsider

Additional focus on resuscitative measures may be required in penetrating injured patients in a rural environment or those with long transport times to the hospital. Denitive control of the airway and blood administration to maintain a perfusing pressure are more likely to be needed in this setting. In addition, the early administration (<3h) of the tranexamic acid should be considered for patients with a signicant risk of hemorrhage.

Deterioration in the mental status as evidenced by a low Glasgow Coma Scale, particularly in the motor or verbal component, has also been shown to correlate with central hypotension and impending demise. The eye component may be difcult to evaluate during transport because of poor lighting and motion during transport. In the intubated patient, the motor component alone is typically followed, since the verbal component score will stay at 1T.

6 Prehospital Monitoring During Transport

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A pulse oximeter is included in the standard equipment on an ambulance providing ALS and is used for continuous peripheral oxygen saturation monitoring in prehospital emergency medicine and transportation. The device measures hemoglobin saturation in a noninvasive fashion by passing a light between two surfaces of tissue. Forehead sensors may give more reliable readings, depending on the location of the injuries. Patient motion, hypothermia, and vasoconstriction can all interfere with accurate readings and cause aberrant results.

EtCO2 monitoring is a means of evaluating respiratory CO2 levels during exhalation. It has become a standard component in an ambulance that provides ALS.Guidelines from the American Heart Association require exhaled CO2 measurement following intubation for the conrmation of accurate endotracheal (ET) tube placement. The qualitative measuring device ts between the Ambu bag and the ET tube and changes color in the presence of alveolar CO2 when levels are near normal pulmonary artery CO2 values. Inadvertent esophageal intubation reveals absent ETCO2. Physiologic derangements such as shock, pulmonary embolism, and airway obstruction may produce a lower EtCO2, while hypoventilation and exogenous bicarbonate administration may elevate the EtCO2. Small reductions in EtCO2 may give an early warning of cardiovascular collapse from hypovolemic hemorrhage, but small quantitative drops have not yet proved to be clinically useful in the prehospital setting.

In summary, monitoring during the transport of penetrating trauma has been standardized with recommended devices found on ambulances that provide both basic and advance life support. A high degree of suspicion or even the expectation that the patient will decompensate en route will decrease the incidence of adverse events. All penetrating trauma except that which is isolated to a distal extremity should be transported to a trauma center with an activated trauma team. On-scene delays including those from non-life-saving interventions should be avoided. In general, physical examination of the patient using standard ABC sequence of trauma care should be followed. Preventable deaths en route are mainly from uncontrolled extremity hemorrhage, loss of the airway, and tension pneumothorax. Monitoring should closely evaluate for these life-threatening conditions. Immediate actions should be taken for each condition using appropriate equipment and techniques. An initial evaluation is performed to determine the needs of the patient and which specic facility is most appropriate for treating the sustained injuries.

Important Points

• The principal goal of EMS providers caring for penetrat-

ing injury patients in an urban environment is rapid trans-

port to denitive care—usually by ground transport.

• Wound location and hemodynamic information should be communicated in a concise prehospital report before arrival to the trauma center.

• Hemodynamically unstable penetrating injured patients in an urban environment may benet from resuscitative measures delivered during the transport (protection of the airway, judicious intravenous uids, and tourniquets).

• Additional focus of resuscitative measures may be required in penetrating injury patients in a rural environment or those with long transport times to the hospital (e.g., air transport, securing of airway, administration of blood products, and antibrinolytic agent).

Suggested Reading

Ausset S, Glassberg E, Nadler R, et al. Tranexamic acid as part of

remote damage-control resuscitation in the prehospital setting: a critical appraisal of the medical literature and available alternatives. J Trauma Acute Care Surg. 2015;78(6 Suppl. 1):S70–5.

Bhende MS, LaCovey DC.End-tidal carbon dioxide monitoring in the

prehospital setting. Prehosp Emerg Care. 2001;5(2):208–13.

Bulger EM, Maier RV.Prehospital care of the injured: what’s new. Surg

Clin N Am. 2007;87:37–53.

Carr ME Jr. Monitoring of hemostasis in combat trauma patients. Mil

Med. 2004;169(12 Suppl):11–5.

Convertino VA, Ryan KL, Rickards CA, etal. Physiological and medi-

cal monitoring for en route care of combat casualties. J Trauma. 2008;64(4 Suppl):S342–53.

Deakin CD, Low JL. Accuracy of the advanced trauma life sup-

port guidelines for predicting systolic blood pressure using carotid, femoral, and radial pulses: observational study. BMJ. 2000;321(7262):673–4.

Donald MJ, Paterson B. End tidal carbon dioxide monitoring in

prehospital and retrieval medicine: a review. Emerg Med J. 2006;23(9):728–30.

Dretzke J, Sandercock J, Bayliss S, etal. Clinical effectiveness and cost-

effectiveness of prehospital intravenous uids in trauma patients. Health Technol Assess. 2004;8(23):103.

Holcomb JB, Niles SE, Miller CC, et al. Prehospital physiologic

data and lifesaving interventions in trauma patients. Mil Med. 2005b;170(1):7–13.

Holcomb JB, Salinas J, McManus JM, etal. Manual vital signs reli-

ably predict need for life saving interventions in trauma patients. J Trauma. 2005a;59(4):821–8.

Jacobs LM, McSwain NE Jr, Rotondo MF, et al. Improving survival

from active shooter events: the Hartford consensus. J Trauma Acute Care Surg. 2013;74(6):1399–400.

Mabry R, McManus JG. Prehospital advances in the manage-

ment of severe penetrating trauma. Crit Care Med. 2008;36(7 Suppl):S258–66.

McManus JG, Ryan KL, Morton MJ, etal. Limitations of end-tidal CO2

as an early indicator of central hypovolemia in humans. Prehosp Emerg Care. 2008;12(2):199–205.

Nuhr M, Hoerauf K, Joldzo A, etal. Forehead SpO2 monitoring com-

pared to nger SpO2 recording in emergency transport. Anaesthesia. 2004;59(4):390–3.

Ryan KL, Batchinsky A, McManus JG, etal. Changes in pulse char-

acter and mental status are late responses to central hypovolemia. Prehosp Emerg Care. 2008;12(2):192–8.

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Sasser SM, Hunt RC, Sullivent EE, etal. Guidelines for eld triage

of injured patients. Recommendations of the National Expert Panel on eld triage, Centers for Disease Control and Prevention (CDC). MMWR Recomm Rep. 2009;58(RR-1):1–35.

Schroll R, Smith A, McSwain NE Jr, etal. A multi-institutional anal-

ysis of prehospital tourniquet use. J Trauma Acute Care Surg. 2015;79(1):10–4.

Seamon MJ, Fisher CA, Gaughan J, etal. Prehospital procedures before

emergency department thoracotomy: “scoop and run” saves lives. J Trauma. 2007;63(1):113–20.

Shatney CH, Homan SJ, Sheck JP, etal. The utility of helicopter trans-

port of trauma patients from the injury scene in an urban trauma system. J Trauma. 2002;53(5):817–22.

Stockinger ZT, McSwain NE Jr. Prehospital endotracheal intubation for

trauma does not improve survival over bagvalve-mask ventilation. J Trauma. 2004;56(3):531–6.

Sukumaran S, Henry JM, Beard D, et al. Prehospital trauma man-

agement: a national study of paramedic activities. Emerg Med J. 2005;22(1):60–3.

Vajda P.Prehospital care of the adult trauma patient. Bratisl Lek Listy.

2007;108(8):371–4.

Trauma Resuscitation

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RachelMorris andMarcde Moya

Hemorrhage accounts for up to 40% of trauma-related deaths. As hemorrhage has been increasingly recognized over the last century as both a disease of decreased perfusion and a disease of altered immunity, the approach to trauma resuscitation has evolved substantially. However, one must not forget the teleologic evolution to hemorrhage which includes hypotension. While the initial approach to the management of the penetrating trauma patient remains addressing airway and breathing prior to circulation, there is an immediate need to control the hemorrhage while resuscitating the patient. One should never equate resuscitation with hemorrhage control but how one resuscitates will directly impact the hemorrhage control. This concept is known as damage control resuscitation. In the face of penetrating trauma, the means to improve survival is expeditious hemorrhage control and minimizing secondary soft tissue/organ injury with resuscitative efforts to maintain end-organ perfusion and reverse trauma-induced coagulopathy. This chapter will focus on the resuscitation for penetrating trauma patients who present with hemorrhagic shock. Table7.1 reviews the classication of hemorrhagic shock.

R. Morris · M. de Moya (*) Division of Trauma & Acute Care Surgery, Medical College of Wisconsin/Froedtert Trauma Center, Milwaukee, WI, USA e-mail: ramorris@mcw.edu; mdemoya@mcw.edu

Table 7.1 Classes of hemorrhagic shock [1]

Class I Class II Class III Class IV

EBL (mL)

EBL (% TBV)

Pulsea (bpm)

SBP PPa

(mmHg)

RR UOPa

(mL/h) MS

EBL estimated blood loss, TBV total blood volume, BPM beats per minute, SBP systolic blood pressure, PP pulse pressure, RR respiratory rate, UOP urine output (if catheter inserted), MS mental status

Underlying comorbidities and medication use may alter these manifes-

tations of hemorrhage

<750 750–1500 1500–2000 >2000

<15 15–30 30–40 >40

<100 100–120 120–140 >140

Normal Normal Decreased Decreased Normal or

increased 14–20 20–30 30–40 >35 >30 20–30 5–15 Nil

Slightly anxious

Decreased Decreased Decreased

Mildly anxious

Anxious, confused

Confused, lethargic

7.1 Fluid Type

There is data to support the use of small volumes of crystalloid in patients who present with class I/II hemorrhage, such that the deleterious effects of volume overload are avoided while maintaining both macro- and microperfusion. However, large-volume crystalloid resuscitation in the face of exsanguinating hemorrhage has been shown macroscopically to cause edema of the gut, myocardium, and skeletal muscles, compartment syndrome, and acute respiratory distress syndrome. Microscopically, this type of resuscitation induces tissue hypoxia and free-radical injury, leading to derangements of cellular, metabolic, and immune functions. Meanwhile, the traditional approach to blood component transfusion for class III/IV hemorrhagic shock wherein one unit of fresh frozen plasma (FFP) was transfused for every six units of packed red blood cells (PRBCs) and one unit of platelets transfused for every ten units of PRBCs has been

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R. Morris and M. de Moya

shown to result in acidosis, hypothermia, and coagulopathy. When this so-called lethal triad occurs, diffuse hemorrhage continues despite operative control at the injury site(s) and often results in death. Therefore, large-volume crystalloid infusion has largely been replaced by blood product transfusion in xed ratios of red blood cells/plasma/platelets approaching 1:1:1 or 1:1:2 as evidenced by the Pragmatic Randomized Optimal Plasma and Platelet Ratios (PROPPR) trial, which did not show 24h or 30-day mortality differences between these ratios. Even when ratios are maintained, increasing volume of crystalloid prior to balanced resuscitation is a predictor of mortality. Finally, there are mortality benets from an established protocol that includes a balanced ratio of blood products while minimizing crystalloid solution infusion. These protocols facilitate quick access to appropriate blood products.

Colloids (typically 5% albumin or 6% hetastarch) and hypertonic uids (7.5% saline with or without 6% dextran) have been evaluated as alternatives to crystalloids for their higher oncotic pressure and hypertonicity, but numerous studies failed to show any mortality advantage when compared to isotonic uids. Similarly, given that blood component therapy suffers from lack of donors, storage issues, and risks of transfusion, various hemoglobin solutions that would potentially provide the benets of blood transfusion, in particular with regard to oxygen-carrying capacity, without the risks and with longer shelf lives, were created and tested. Unfortunately, none have shown the mortality benet hoped for, and some have been associated with signicant adverse effects, including higher mortality.

Thus, blood products in a 1:1:1 or 1:2:1 ratio, with little to no crystalloid solution, along with efforts to control source of hemorrhage, either temporarily, or denitively if able to be achieved outside of the operating room, should be the initial approach to resuscitation after penetrating trauma for patients in hemorrhagic shock. Furthermore, all hospitals should establish massive transfusion protocols (MTPs) based on local resources designed to bring appropriate balanced ratio of blood products to the patient in less than 10min.

7.2 Determining theNeed forMassive

Transfusion

If an injured patient has evidence of intact perfusion as measured by normal blood pressure or evidence of end-organ perfusion (intact mental status, palpable radial pulse), he/she does not need to be aggressively resuscitated or transfused. Immediate hemorrhage control is key to clinical outcomes. In recent years, a number of approaches to determining the need for massive transfusion, retrospectively dened by most as the need for ≥10 unit PRBCs in the rst 24h after injury, have been tested.

The trauma-associated severe hemorrhage (TASH) and the assessment of blood consumption (ABC) scores are the most widely used. However, the former was derived from a cohort of blunt trauma patients and consists of a relatively complicated calculation utilizing seven weighted variables (systolic blood pressure, sex, hemoglobin, focused assessment for the sonography of trauma (FAST), heart rate, base excess (BE), and extremity or pelvic fractures) to predict the need for massive transfusion. The possible range of scores is between 0 and 28, where each point corresponds to increased risk, and 100% of patients with a score≥27 require massive transfusion. Conversely, ABC accounts for mechanism of injury (penetrating vs. blunt) and is simpler to derive. It also includes systolic blood pressure≤90mmHg on emergency room (ER) arrival, heart rate≥120bpm on ER arrival, and positive FAST, where each parameter equals 1 point and 85% of patients with a score of ≥2 will require massive transfusion. Application of such scores to MTP practices will streamline resource utilization and clinical decision-making at the bedside when patients are not in obvious class III or IV hemorrhagic shock.

7.3 Adjuncts toMassive Transfusion

Trauma-induced coagulopathy (TIC) occurs when the body’s hemostatic mechanisms at the cellular level become deranged in the face of massive exsanguination. Thrombus can no longer form and uncontrolled hemorrhage, not just from the site(s) of injury, occurs. TIC occurs in 10–34% of injured patients and has been associated with increased mortality. While early research suggested that high-volume crystalloid infusion and wide blood product ratios were causative factors, it appears that these approaches to resuscitation were actually exacerbating, rather than inducing, post-injury coagulopathy which has been attributed to increased activation of activated protein C, hyperbrinolysis, and platelet dysfunction due to injury itself. Therefore, in addition to limiting (in the case of crystalloids) or modulating (in the case of blood product ratios) these exacerbating factors as detailed above, efforts to identify and ameliorate TIC have also emerged.

Traditional approaches to measuring coagulopathy are either impractical (e.g., bleeding time is difcult to measure in a patient undergoing interventions in the trauma bay for hemodynamic compromise; serum laboratory data even if stat can take up to 2h to return) or not reliable (e.g., platelet count does not reect platelet function; brinogen, prothrombin time, and partial thromboplastin time each only reect one aspect of the coagulation cascade) for patients presenting with hemorrhagic shock; therefore, point-of-care testing of whole-blood viscoelasticity has been developed. The two most widely studied in trauma are thromboelastog-

7 Trauma Resuscitation

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Normal

Anticoagulants/

hemophilia

Anti-platelet agents

Table 7.2 Reversal agents for common oral anticoagulants

Anticoagulant class Examples Reversal

Vitamin K agonists

Direct thrombin inhibitors

Direct factor 10A inhibitors

Platelet inhibitors

PPC prothrombin complex concentrate, FFP fresh frozen plasma

Warfarin 3-factor or 4-factor PCC or

Dabigatran PCC, recombinant factor

Apixaban, rivaroxaban, edoxaban

Aspirin, clopidogrel

FFP (if PCC is not available)

VIIa, or hemodialysis (if PCC/VIIA is not available)

PCC

Platelets or desmopressin

Fibrinolysis

Hypercoagulation

Fig. 7.1 Schematic of interpretation of thromboelastography

raphy (TEG) and rotational thromboelastometry (ROTEM). TEG and ROTEM demonstrate which part(s) of the coagulation cascade is impaired. While the validity of these measures has not denitely been proven in a prospective manner, TEG and ROTEM results allow assessment of adequacy of clotting factors, platelet function, and brinolysis. A detailed discussion of the interpretation of TEG and ROTEM is beyond the scope of this chapter; however, Fig.7.1 provides a schematic of how a TEG or ROTEM result might be interpreted to guide resuscitation. Importantly, normal TEG or ROTEM does not rule out bleeding. Rather, it conrms normal coagulation cascade. Several centers have reported using TEG or ROTEM in the trauma bay to guide resuscitation with specic blood components, cryoprecipitate, concentrated clotting factors, and pharmacologic adjuncts rather than blindly following a prescribed ratio of blood components for patients in hemorrhagic shock. Based on current evidence, these point-of-care tests should be considered in conjunction with MTPs when available.

Tranexamic acid (TXA) is a synthetic derivative of the amino acid lysine that inhibits brinolysis. It is indicated for primary hyperbrinolysis, both acquired and inherited. The effectiveness of TXA in the face of “signicant hemorrhage” was measured in the large clinical trial Clinical Randomisation

of an Antibrinolytic in Signicant Haemorrhage (CRASH- 2). The study found that administering 1g of TXA within 3h of onset of bleeding as a bolus over 10min and then providing a maintenance dose of 1gm infused over the next 8h reduced all-cause mortality from 16 to 14.5% (RR

0.91, 95% CI 0.85–0.97) without increasing thrombotic events. Since this study was published, administering TXA in concert with an MTP has been widely adopted. These reports support including TXA in modern-day MTPs for patients who present within 3h of onset of bleeding.

Pharmacologic coagulopathy, in particular in the era of novel oral anticoagulants, is also a concern in the resuscitation approach after penetrating trauma. Pharmacologic coagulopathy should be considered based on patient history, if known; and, in certain cases, TEG or ROTEM is less reliable in determining the class of agent (see Fig. 7.1). Reversal strategies for various anticoagulants differ and should be immediately implemented in an exsanguinating trauma patient. While a detailed discussion of reversal of pharmacologic coagulopathy is beyond the scope of this chapter, common recommendations for oral anticoagulants are listed in Table7.2. As with MTPs, protocolization of reversal of common anticoagulants may expedite hemorrhage control.

Whether due to environmental exposure at the time of injury or blood loss, hypothermia has been reported in 2–13% of injured patients. Hypothermia, typically dened as core temperature≤35°C, exacerbates TIC by causing consumption of clotting factors and has been independently associated with mortality in a number of studies. Therefore, during resuscitation, every effort must also be made to warm the environment and avoid hypothermia. All wet/cold clothing must be removed and replaced by warm blankets. Room temperature should be maintained at 28°C.These are examples of passive external warming. Active external rewarming involves conduction or convection blankets at 42°C.Finally, whether or not a patient is hypothermic on presentation, to avoid iatrogenic cooling, all PRBCs, FFP, and uids (if any) must be infused via warmers at a temperature of approximately 38 °C.Recent evidence also refutes the traditional

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R. Morris and M. de Moya

recommendation that platelets not be infused through a warmer due to poorer aggregation. More invasive intra- or extracorporeal warming is rarely used in the acutely injured patient.

7.4 Permissive Hypotension

Normotension in the absence of hemorrhage control has been shown to worsen bleeding in multiple experimental models. Therefore, hypotensive resuscitation, controlled resuscitation, and delayed resuscitation until the time of denitive hemorrhage control have been proposed as alternatives for patients without suspicion of intracranial injury (since even a single episode of hypotension can worsen neurologic outcomes). The landmark study that led to this paradigm shift allowing for permissive hypotension in the management of trauma patients, in particular those with penetrating trauma, randomized patients with penetrating torso trauma and systolic blood pressure < 90 mmHg to delayed (N = 289) versus conventional resuscitation (N=309) in the eld. The study, set in an urban US environment with short transport times, showed that the delayed resuscitation group experienced higher survival than controls (70% vs. 62%, p=0.04) without any difference in complication rates. Since that time, various strategies for permissive hypotension have been proposed and tested.

In hypotensive resuscitation, infusion rates are adjusted to maintain a goal blood pressure (typically mean arterial pressure of 40–50 mmHg or systolic blood pressure of 80–90mmHg). In controlled resuscitation, which is particularly useful in prehospital or austere environments where sphygmomanometry may not be available, the rate of uid infusion is maintained at a predetermined rate (60–80mL/ kg/h) selected a priori so that there is little chance of achieving normotension. In delayed resuscitation, uids are withheld until denitive hemorrhage control. This may be particularly useful in areas with short transport times. Ultimately, resuscitation is not a substitute for early hemorrhage control; however, pending such control, mammalian models and limited clinical studies support permissive hypotension.

Important Points

• Minimize time to denitive hemorrhage control.

• Avoid hypothermia.

• Minimize crystalloid infusion.

• Consider permissive hypotension in patients without sus-

pected intracranial injury.

• Implement a massive transfusion protocol that includes

tranexamic acid.

• Utilize established scoring systems to initiate massive transfusion protocols.

• Reverse pharmacologic coagulopathy if present.

• Administer blood components in a narrow, balanced ratio.

• STOP THE BLEEDING.

Reference

1. Mutschler M, Nienaber U, Brockamp T, Wafaisade A, Wyen H, Peininger S, Paffrath T, Bouillon B, Maegele M, the TraumaRegister DGU. A critical reappraisal of the ATLS classication of hypovolaemic shock: Does it really reect clinical reality? Resuscitation. 84(3):309–13.