Scott R. Karlan
Daniel R. Margulies
The many chapters of this book testify to the many facets of critical care. Most are applicable to trauma patients in the intensive care unit (ICU). In contrast, the initial management of the trauma patient requires a different focus and prioritization. This chapter presents common life-threatening problems that face all critical care physicians who care for trauma victims.
Trauma patients look different. Most start out younger and healthier than other ICU patients but the severity of many of their injuries mandates expert critical care management. How does initial trauma care differ from other critical care treatment? Time is the key. Many of the more common traumatic injuries are rapidly lethal. One's desire to thoroughly evaluate a trauma patient must therefore be tempered by a need to prioritize within available time. This prioritization, aided by careful planning and a team approach, contributes to patient survival.
The Team
Your treatment plan needs to start before the next trauma patient arrives. A multiply injured patient may require several simultaneous interventions. Having a team of physicians, nurses, technicians, therapists, and aides allows for parallel rather than sequential treatment. Adding personnel (e.g., x-ray technicians, respiratory therapists, surgical specialists) to your team encourages these individuals (and their departments) to commit to trauma care, potentially reducing treatment delays. Noise rises exponentially with the size of the team, making it difficult to communicate or to auscultate breath sounds and heart tones. Having a common paging system for all members of the team is essential to reduce redundancy and activate the necessary team prior to the arrival of the patient at your hospital. This activation system can be a tiered response depending on the facility you work in. Regardless, critically reviewing prior trauma resuscitations in your facility will reveal any needed additions or deletions of members to your team.
Take a lesson from the National Association for Stock Car Auto Racing (NASCAR). To function as a team, you need to practice as a team. Mock trauma drills allow you to do it over until you do it right. Do you have more than one chest tube set? How long does it take to get the drugs for a rapid sequence induction and intubation? Do you even have a pediatric endotracheal tube? A NASCAR team can change four tires and fill the gas tank in about a minute. Your team will need to establish IV access and administer fluid, gather baseline vital signs, and complete the primary survey in this time frame. Do team members understand the big picture (what needs to be done for the patient) beyond their specific assignments? Are they prepared to shift roles when necessary (e.g., when a patient needs intubation, or when IV access is problematic)? If you have team members trained in the medical intensive care unit, can they “think surgically,” as intervention may be needed without a clear diagnosis?
As you build a team, think outside the hospital. Organized trauma networks reduce preventable deaths (1,2). By joining such a network, your hospital integrates paramedics and other field triage personnel into your team. Although the number of trauma centers has risen from 471 in 1991 to 1,154 in 2002 (including 190 level I and 263 level II centers) (3), 46 million Americans still live more than an hour from a level 1 or 2 center (4). Committing the resources to become a level I or level II trauma center will optimize care at your hospital and in the community. These resources include on-site trauma surgeons, immediately available operating rooms, rapidly available surgical specialists, a trauma manager, quality improvement processes, and other benefits.
Triage
Called to the scene of an accident, paramedics initially triage the victims. They determine who to transport and when and where to take them (following established community protocols). In all cases, the number of patients and severity of their injuries are weighed against available resources. Ideally the most severely injured are taken to the center most capable of treating that patient, so when many injuries occur at the same time they may be divided between available hospitals. Blunt and penetrating urban trauma typically involves relatively few patients at a time. Several simultaneous incidents may occur and may overwhelm a community. September 11 has taught us that we need to prepare for multiple victims.
In a mass casualty event, you may need to evacuate the emergency department (ED) to make room for incoming patients. The seriously injured will be brought in slowly as patients with minor injuries flood into your waiting room. ED physicians normally stay with the ED patients as they are moved elsewhere in the hospital. Although surgeons will be needed in the operating room, it is important that the vital role of making these initial triage decisions be filled by someone who is experienced in trauma management and understands the physiology of traumatic injury.
Triage is most effective at “ground zero,” a site in the field where patients are gathered prior to transport. If roads and communications are disrupted, much of the initial trauma care may need to be provided at that site. Ideally, a physician with trauma experience and knowledge of community resources goes to the field to oversee triage rather than waiting in the emergency department.
Paramedics play a critical role even when triage is not an issue. Their observations may be the only medical history that is ever available. Did they speak to witnesses of a shooting? How far did a patient fall? Was extrication necessary after a car crash? How much blood was at the scene? Paramedics will communicate most of this information to the trauma team upon arrival, along with any other observations (patient stability, apparent injuries). Radio communication provides much of this prehospital information, but direct communication with the paramedics before they leave is important. Knowing about likely injuries allows you to focus on treating the patient, rather than listening to paramedics, when the patient arrives. If paramedics have already started two large-bore IVs, intubated the patient, and given 2 liters of fluid, your priorities will change. Every minute of advance warning can save critical seconds later on.
Prioritization
The American College of Surgeons, through its Advanced Trauma Life Support (ATLS) course (5), has taught generations of physicians and nurses to focus on the ABCDE's of trauma. “Airway, breathing, and circulation” is worth repeating over and over as you struggle to revive a trauma victim. When circumstances go from bad to worse (e.g., multiple simultaneous life-threatening injuries, in a deteriorating patient not responding to resuscitation), remember the ABC's. An obstructed airway is lethal within minutes. Securing an airway can buy enough time to address many other injuries. For this reason, it is more important to look for airway obstruction (even in intubated patients) than for intracerebral bleeding, aortic dissection, pancreatic transection, or virtually any other injury.
After ensuring the ABCs, “D” is a reminder to consider disability or, more specifically, to perform a rapid neurologic assessment. At the bare minimum, this should include an assessment of the patient's pupils (size and reaction to light), extremity motion (looking for lateralizing signs), and Glasgow coma scale. Assessing strength and sensation requires an awake, cooperative patient. In an unstable patient or patient with an altered mental status (from alcohol, drugs, or head trauma), you may need to complete the neurologic examination later that day or the following day. The Glasgow coma scale is primarily used as a tool for sequential assessment. Patients with head trauma or an altered mental status should be rescored every few hours. Their score should improve as they recover (or sober up), and deterioration warrants prompt re-evaluation and/or repeat computed tomography (CT) scanning.
“E” reminds you to expose the patient. Cutting off clothes may seem wasteful until you miss an unsuspected wound, or find a knife, by radiography, in pants that should have been removed. Slight tracheal deviation may be the only sign of a tension pneumothorax. The odds of identifying this are vastly improved if the patient is exposed.
Placing a blanket warmer in the emergency room allows you to quickly cover and uncover a patient. This mitigates the hypothermia caused by cold IV fluid, field exposure, and ED exposure. Blunt trauma, in particular, causes bleeding from both small and large vessels. Platelets and clotting factors normally control the small-vessel bleeding, allowing the surgeon to focus on the large vessels. Coagulopathy vastly complicates the surgeon's task, adversely affecting survival. In the ICU setting, coagulopathy is most often caused by a drug overdose (e.g., heparin) or an adverse drug reaction. In trauma, coagulopathy is multifactorial. Ongoing bleeding, attempted clotting, and crystalloid resuscitation lead to the direct loss, consumption, and dilution of platelets and clotting factors. With mild hypothermia, platelets adhere poorly. Below 33°C, coagulation enzymes fail. Once the core body temperature drops below 32°C, trauma patients have a 100% mortality (6). Hypothermia is a preventable cause of death mitigated by simple measures like warming the ED trauma bay and operating room.
The Primary Survey
ATLS divides the patient's initial evaluation into a primary and secondary survey. The primary survey focuses on high-priority injuries: those that are rapidly lethal and rapidly correctable. Many common injuries are rapidly lethal. Rapidly correctable implies that you can fix (or temporize) the problem using simple tools (a laryngoscope, a chest tube, direct pressure, etc.) kept in an ambulance or in the ED. The primary survey is designed to identify such injuries (Table 72.1).
Airway Obstruction and Airway Management
Airway management is a common cause for anxiety. Failure in airway maintenance rapidly leads to death. Apart from the rare patient with severe facial trauma who requires an immediate cricothyroidotomy, trauma patients should be approached in a standardized fashion. Assume that all patients are at risk for a respiratory arrest, and for a cervical spine injury, and are likely to have a full stomach.
Patients are categorized into three groups: (a) those who are awake, alert, and breathing with no difficulty at all; (b) those in respiratory distress who need immediate intubation; and (c) everyone else. The first group should be treated with periodic reassessment. With the second group, check for airway obstruction while setting up for a rapid sequence induction and intubation. Simple measures, like a jaw thrust or chin lift, or an oral or nasal airway, rarely allow you to avoid intubation. However, these maneuvers may convert an emergent intubation into a semi-elective intubation. The third group includes all of the patients who don't need intubation at that moment, but who may be close to needing it or who may need it in the future. This is the group that requires judgment. Trauma patients with an altered mental status but with no respiratory distress will be sent for a head CT scan. Some will stop breathing in radiology, a suboptimal place for an emergent intubation. If you try to intubate every patient prior to CT, you will fail 2% to 3% of the time (7). Failure to obtain an airway can be managed if you have a backup plan (8), including cricothyroidotomy. Generally, intubate patients with a Glasgow coma scale score of 8 or less. If a patient has no mental status changes but needs to go to the operating room, consider early intubation prior to transport, particularly if the patient has been hypotensive. If you have any doubt, err on the side of intubating the patient.
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Table 72.1 The focus of the primary survey |
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The best way to intubate a patient is the way that works best for you. Be consistent. Pick one set of drugs and your favorite Macintosh or Miller blade. If you develop a routine, you will be reminded to use suction and to apply cricoid pressure. Your success depends less on your speed and more on your skill with mask ventilation. Preoxygenation is critical. Several minutes of effective mask ventilation with 100% oxygen will create a luxurious amount of time to inspect the airway and place an endotracheal tube without disturbing the spine. Not every patient needs sedation. In an unresponsive patient, you can bypass the rapid sequence induction unless you have selected the drugs to reduce intracranial pressure during intubation.
Airway Management and the Cervical Spine
Any patient who rapidly decelerates (e.g., motor vehicle accident, fall) requires spinal stabilization. Such a patient should arrive on a backboard with a collar. Also consider spinal injuries after direct trauma to the head, neck, or back. Clearing the cervical spine requires more than a radiograph as ligamentous injuries can occur in the absence of radiologic findings. In an alert, cooperative patient who has no neck tenderness, no distracting injury, and a normal neurologic examination, the collar may be safely removed (9). Unfortunately, neck tenderness and mental status changes are common. In such patients, clearing the C-spine is not an immediate priority and should be delayed until they are stable. Clearance criteria are controversial and may require a C-spine series or CT of the neck, to rule out fractures, followed by flex/ex (flexion/extension) views or magnetic resonance imaging (MRI) of the neck, to rule out ligamentous injuries.
Protecting the spine is occasionally at odds with needed intervention. This occurs most often during intubation, although there are other circumstances where it may be necessary to transiently remove the front of the collar. This conflict is best overcome by assigning one team member to maintain in-line stabilization (not traction) while other team members perform necessary interventions. Although direct laryngoscopy will angulate the spine despite in-line stabilization (10), orotracheal intubation can be performed safely in patients with cervical spine fractures when reasonable precautions are taken (11). Fiberoptic intubation can be done without any movement of the neck and should be considered in high-risk patients when time permits. While nasotracheal intubation also avoids spinal manipulation, it is rarely used in trauma because it requires an awake, breathing patient; takes time to perform; can cause nasal bleeding; and can lead to vomiting and aspiration.
Pneumothorax and Tension Pneumothorax
Pneumothorax is one of the most common thoracic injuries. As a consequence, any physician caring for trauma patients should be comfortable placing a chest tube. Air usually enters the pleural space from a lung injury, although it may also enter through a chest wound. During normal inspiration, the diaphragm contracts, intrapleural pressure falls, and the lung expands via the bellows effect. If the pleural space contains trapped air, the lung cannot fully expand. Blood then circulates through nonaerated alveoli, leading to hypoxia. Despite this, healthy patients can generally tolerate the complete collapse of one lung.
Tension pneumothorax starts in a similar manner; however, the pathophysiology soon diverges. Some lung injuries act as a one-way valve. Inspiration pulls air into the pleural space. Expiration compresses the lung and obstructs air egress. As pleural pressure builds, the mediastinum is pushed to the contralateral side (shifting the trachea), eventually kinking the superior vena cava and inferior vena cava. Venous pressure then rises (distending the neck veins) and venous return falls. As preload drops, cardiac output drops, and then blood pressure drops. Patients die from cardiogenic shock, not hypoxia, although hypoxia may also be present. If a patient with a chest injury becomes hypotensive after intubation, consider tension pneumothorax. Positive pressure ventilation can rapidly raise the intrapleural pressure in these patients.
Tension pneumothorax is both rapidly lethal and rapidly correctable. There are several mandatory treatments. The first should be decompression. If you suspect tension pneumothorax, perform needle thoracostomy (or expeditiously place a chest tube). Do not wait for chest radiograph confirmation. Use the largest IV catheter immediately available (ideally 14 or 16 gauge). Place the catheter in the second or third intercostal space, in the midclavicular line, aiming toward the back. This will decompress the pleural space. Whether or not the patient had a tension pneumothorax, the outcome will be a simple pneumothorax. A chest tube should be placed at the earliest opportunity. A small chest tube (e.g., 20 French) placed anteriorly will work, but most chest injuries involve some degree of bleeding and a large chest tube (e.g., 36 French) is preferable. Place it in the fifth intercostal space in the midaxillary line high enough to avoid hitting the liver or spleen. Although tube thoracostomy is optimal treatment, it takes a few minutes to complete. As death can occur rapidly, needle thoracostomy should be considered first unless you have all the equipment actually in your hands.
Volume loading should be done simultaneously for treating a tension pneumothorax. If you have a patient who is hypotensive and hypoxic with distended neck veins and tracheal shift, turn up the IV as you look for a catheter for needle thoracostomy. Increasing the venous volume (and pressure) will overcome the venous obstruction (until the mediastinum shifts further). This will not treat the hypoxia, but it will raise the blood pressure for a few minutes. As with other interventions, the goal of initial trauma care is to buy time for definitive treatment.
Open Pneumothorax and Flail Chest
In an open pneumothorax, there is a large hole into the chest. As the patient tries to breathe, air moves in and out through the hole. For this reason, an open pneumothorax is also known as a sucking chest wound. Intrapleural pressure never falls, so the ipsilateral lung never expands. There are two treatment options. If you cover the hole, you create a simple pneumothorax, which can then be treated with tube thoracostomy. If you intubate the patient, positive pressure ventilation will expand both lungs regardless of the presence of an open pneumothorax.
Flail chest has similar pathophysiology. If three or more ribs are broken in two places, the “flail” segment moves in and out as the patient tries to breathe. As with open pneumothorax, there are three choices: you can place a chest tube, intubate the patient, or both. Unfortunately, the force needed to cause these injuries usually damages the adjacent lung. Although treating the flail segment is easy, patients may still die from the associated pulmonary contusion and hypoxia.
Cardiac Tamponade
Beck's triad (hypotension, jugular venous distention, and muffled heart sounds) and pulsus paradoxus (an exaggerated drop in systolic blood pressure of >10 mm Hg with inspiration) are the hallmarks of cardiac tamponade. These clinical signs are less reliable in trauma. Hypotension is nearly universal, hypovolemia may prevent jugular venous distention, and ED noise obscures heart sounds. Clinical suspicion (any wound near the heart) is essential to making this diagnosis, although cardiac tamponade has been rarely reported after minor chest trauma (12). The widespread adoption of focused abdominal sonography for trauma (FAST) has made it easier to identify cardiac tamponade.
Cardiac tamponade is both rapidly lethal and rapidly correctable. For this reason, patients who present in shock after chest trauma have a better chance of survival if they present with cardiac tamponade (13). As blood enters the rigid pericardial sack, it prevents the heart from filling during diastole. Venous return is obstructed, venous pressure rises, and cardiac output falls. The rapid infusion of IV fluid will transiently raise the blood pressure (14), but decompression is key, followed by definitive correction of the underlying injury. The pathophysiology is similar to tension pneumothorax. Although rare, tension pneumomediastinum presents (15) in an identical fashion and can also be treated with mediastinal decompression.
In the nontrauma setting, pericardiocentesis, done with a pigtail catheter under ultrasound guidance, is the treatment of choice. Pericardiocentesis has been used effectively for trauma (16). However, the preferred treatment is subxiphoid pericardial window (17) or emergency room thoracotomy (with pericardial fenestration) whenever a surgeon is available. Decompression buys time but rarely addresses the underlying injury. Most trauma patients with cardiac tamponade should therefore be expeditiously taken to the operating room for median sternotomy or anterolateral thoracotomy.
Peripheral Arterial Injuries
Significant arterial bleeding from extremity laceration is sometimes “audible.” Direct pressure is the treatment of choice, particularly with peripheral arterial injuries. Tourniquets cut off collateral circulation and are best reserved for those situations where you need to stop bleeding while carrying the victim to safety. Direct clamping is instantaneously effective, but may be difficult in the emergency room with limited light, suction, and retraction. Even when applied properly, a clamp may crush the artery, reducing the length available for a primary anastomosis. As arteries travel with nerves and veins, direct clamping may damage adjacent structures. For these reasons, direct pressure is preferred, even though it may fully occupy one person.
Resuscitation
Resuscitation starts in the field and continues after arrival. Administer fluid rapidly if justified by the mechanism of injury. It is rare for a patient to develop congestive heart failure from resuscitation in the emergency room even if they have underlying cardiac disease. In contrast, underresuscitation is common (18). Young, athletic patients may be able to compensate for significant blood loss without tachycardia or hypotension. Essential hypertension and heart block also make it difficult to interpret vital signs in the elderly. As a sign of shock, tachycardia is more sensitive than hypotension; however, tachycardia may reflect pain rather than blood loss. With the foregoing caveats, continuously monitoring the vital signs is the best way to gauge the efficacy of ongoing resuscitation (Table 72.2).
If you can palpate a pulse, you can estimate the blood pressure. As a general guide, a palpable carotid pulse implies that the blood pressure is at least 60 mm Hg; a femoral pulse implies that the blood pressure is over 70 mm Hg; and a radial pulse implies 80 mm Hg.
Intravenous Access
“Two large-bore IVs, placed at different sites” is a tenet of trauma resuscitation. With too many IVs, the tubing tangles and hampers patient transfers. “Large bore” implies that the line can be used to rapidly transfuse blood. The infusion rate depends on pressure and resistance. Commercial warming equipment (e.g., Level 1 or Rapid Infusion System) as well as simple pressure bags can greatly increase the transfusion pressure. Resistance varies with blood viscosity (which increases with refrigeration) and line (tubing plus IV catheter) impedance. Large IV catheters (6 or 8 French) are readily available and can be placed easily using the Seldinger technique. With large IV catheters, the transfusion rate is limited by the tubing itself. A shorter length and larger diameter are advantageous. Catheter impedance increases exponentially (to the fourth power of the radius) as the catheter gets smaller. For this reason, 18-gauge catheters can be problematic and smaller catheters should not be used.
If you place femoral lines in patients with pelvic trauma, you may find one of your lines infusing into the peritoneal cavity through a lacerated iliac vein. Whenever possible, place IV lines away from the site of trauma. Choose a different extremity for the second line. If the first is in the arm, place the second in the groin or leg (and vice versa). Separating IV lines maximizes the likelihood that infused fluid will reach the heart.
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Table 72.2 Estimated fluid and blood losses based on patient's initial presentation |
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Colloid, Crystalloid, and Blood Substitutes
How best to replace lost blood has been a perennial topic of controversy. Restoring volume can be achieved with colloid or crystalloid. Restoring oxygen-carrying capacity requires red cells.
Crystalloid should be used first in trauma resuscitation. It is readily available, inexpensive, and free of viruses and allergic reactions. As rapid infusion may be necessary, it must be isotonic. Normal saline (0.9% NaCl) is the preferred solution if you need to administer blood through the same line. Since normal saline contains 154 mEq of sodium and no potassium, large amounts lead to hyperchloremia and hypokalemia. Ringer lactate and Ringer acetate avoid this problem by reducing the sodium and adding potassium (and calcium).
Unlike blood, which is confined to the vasculature, crystalloid equilibrates throughout the interstitial and intracellular spaces. As a consequence, 3 liters of crystalloid is needed to replace 1 liter of blood. ATLS recommends starting O-negative or type-specific blood (if available) after 2 liters of crystalloid have been given and the patient remains hypotensive. Nonetheless, a huge volume of crystalloid may be needed in a badly injured patient. This inevitably leads to peripheral edema and if the heart cannot pump the fluid forward, pulmonary edema may develop (19). In order to reduce the time and volume of fluid needed for resuscitation and to reduce the associated edema, several alternatives have been studied. Small-volume resuscitation has been attempted with hypertonic saline (7.5% saline), colloid (albumin, dextran, gelatins, hydroxyethyl starch), and hypertonic saline plus colloid (20,21). Despite the potential advantages of these small-volume resuscitations, which have been of particular interest to the military, crystalloid appears to be associated with a lower mortality in trauma (22,23).
Blood substitutes have advanced from theory to phase 3 clinical trials. Perfluorocarbons and hemoglobin-based oxygen carriers (HBOCs) share many of the benefits of crystalloid: they can be produced in large quantities with a long shelf life, they are universally compatible, and they are free of viruses and allergic reactions (24). Early formulations were plagued by toxicity (vasoconstriction, neurotoxicity, renal dysfunction, and impaired immunity). However, new polymerized HBOC formulations should reduce the volume needed for resuscitation with fewer adverse reactions (25).
As you contemplate your choices among crystalloid, colloid, and blood substitutes, it is worth emphasizing that pressors should never be used as the therapy for traumatic shock and should only be used in spinal shock after volume resuscitation. Spinal cord injuries occur in patients with occult intra-abdominal or intrathoracic bleeding. If your patient has any degree of hemorrhagic shock, volume expansion is essential. Patients with neurogenic shock may respond to a lesser extent, as volume expansion improves cardiac output, which helps to compensate for the loss of vascular tone.
Permissive Hypotension
The goal of resuscitation is to restore normal perfusion and oxygen delivery. In experimental models of uncontrolled hemorrhagic shock, aggressive resuscitation actually increased mortality by increasing the bleeding from injured vessels (26). Human studies (27,28), including one prospective study in patients with penetrating torso trauma (29), have also suggested that fluid resuscitation should be delayed until bleeding can be controlled. These studies done in younger patients with penetrating torso trauma should not be extrapolated to other types of patients until further studies are done. Permissive hypotension, where patients are resuscitated to a less than normal blood pressure, is also supported by animal and human studies (30). Underresuscitating a patient may be lethal. Overresuscitation may also be detrimental. Ultimately, the degree of resuscitation may be less important than the time it takes to get definitive control of bleeding.
The Secondary Survey
This chapter has explored the initial management of the trauma patient. After ruling out injuries that are rapidly lethal and rapidly correctable, many other injuries remain. Some are severe, contributing to death and disability. To avoid missing these injuries, the secondary survey should be thorough, detailed, and compulsive, similar to the critical care detailed elsewhere in this book. Building on lessons from the primary survey and resuscitation, the next chapter reviews the secondary and tertiary surveys, diagnostic evaluation, and definitive treatment.
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