Kenneth L. Mattox, Matthew J. Wall, Jr., and Peter Tsai
Chest trauma was documented in the Edwin Smith Surgical Papyrus, written by Imhotep over 5000 years ago.1 The first recorded operation in the United States was removal of an arrowhead from an Indian’s chest by Cabeza de Vaca in 1635.2 The mortality from chest injury during war has ranged from 28.5% during the Crimean War (1853–1856) to a less than 5% today. Currently, in the United States more than 16,000 deaths occur annually as a direct result of thoracic trauma.3
The chest composes almost one fourth of the total body mass and is therefore often subjected to injury during trauma from any etiology. Regardless of etiology, a patient with thoracic trauma requires logical and sequential evaluation of the chest injury, followed by focused therapy, which, in some instances (less than 20% of the time), involves an operation. Those evaluating and treating must understand the anatomy, physiology, and function of each of the thoracic organs, as well as how each decision and treatment will affect outcome. The acute care surgeon must understand thoracic organ responses to and manifestations of various injuries, appropriate evaluation tools, which evaluations might be misleading, redundant, or unnecessary, and approaches to therapy. It is essential to be able to recognize when minor intervention or damage control should be applied to a chest injury condition verses when a formal surgical intervention is indicated. When surgery is performed the surgeon must also understand benefits and limitations of the various patient positions and incisions. Finally, as every evaluation and therapy has its potential hazard or contraindication, the acute care surgeon must understand traditional concepts that are either dated or currently considered controversial.
Injury to the chest and its organs may be caused by penetration (from missiles, fragments, knives, needles, and other objects), blunt forces, iatrogenic misadventure, blasts, ingestion of toxic substances, and, indirectly, from abnormal medical conditions elsewhere in the body. Each of these etiologies has differing initial manifestations as well as evaluation and treatment approaches.4–6 These differences are more specifically discussed elsewhere in this textbook. This overview chapter contains many cultural views, which have become doctrine and standard use by the authors, but, admittedly, based on Class 3 evidence, which might differ from the culture in other trauma centers.
THORACIC ANATOMY AND PHYSIOLOGY: RESPONSE TO TRAUMA
The thoracic cavity is surrounded by a flexible boney cage, supported by respiratory and locomotive muscles. Three separate compartments house the two lungs with their five segments that are attached by vascular structures to the central cardiovascular compartment. In addition, the trachea and bronchus connect the lungs to the pharynx, and a series of nerves traverse the thoracic cavity. In the healthy patient, the lungs and heart are separated from their surrounding cavities by a smooth fibrous pleural lining. Following inflammation, fusion of these linings may alter some physiology and, consequently, some treatment options. Prior to any procedure following thoracic trauma, the surgeon is well advised to review the regional anatomy, determine position and incision options for a particular technique, and consider all approaches.
Significant technology—from simple physical examination to extremely complex and sophisticated imaging and laboratory testing—exists to assist in the evaluation of a patient with pathology in the chest.7Imaging may involve ultrasound, Doppler technology, classic radiologic tests, helical multidetection computerized technology (CT scans), magnetic resonance imaging (MRI), and others. Other tests available to the surgeon include cardiologic evaluation using EKG, echocardiogram, and even cardiac catheterization. Hematologic, clotting, and metabolic testing, as well as pulmonary function testing are other potentially helpful adjuncts. Endoscopic evaluation of the trachea and esophagus can supplement imaging modalities.
In deciding which evaluation tools to use, first consider what you expect the test to demonstrate and, then, consider how the results will alter decision-making or treatment. Once these questions are considered and answered, the treating physician may well decide the tests are not needed. It is always helpful to have a progress note reflecting the decision-making process—tests ordered/why/why not—in the patient’s medical record.
Tube thoracostomy is both the most common procedure performed following chest trauma and also one of the most misunderstood and underrated operations in medicine. It is the only invasive procedure that most (>85%) of patients with chest injury will require. Upward of 25% of patients with chest tubes will encounter some difficulty with malposition, connection problems, collection system difficulty, pressure abnormalities, or misperceptions and complications at the time of removal. Often, such difficulty can and does result in a clotted hemothorax that is not evacuated, a pleural space problem, a retained pneumothorax, or a recurrent pneumothorax. Far too often, second and multiple chest tubes are unnecessarily inserted as a result of a misunderstanding of the function and technique of tube thoracostomy.
Tube thoracostomy following trauma should be accomplished in as pain and complication free manner as possible. Trocar-tipped chest tubes should be avoided. Chest tubes are best inserted in the area of the auscultatory triangle in the mid-axillary line near the 4th or 5th intercostal space. Subcutaneous tissue and muscular dissection may be accomplished with clamps or dissecting scissors, but the pleura should be opened with an exploring finger, not a sharp instrument. Care is taken to avoid injury to the intercostal vessels and nerve on the under surface of each rib, as such injury can produce iatrogenic bleeding and pain. Following a gentle digital exploratory thoracotomy, an appropriately sized chest tube (32–36 French) is directed toward the back and apex of the pleural space and attached to an appropriate collection device. This insertion site overlies the major pulmonary fissure. Care must be taken to assure that the chest tube is not in this fissure, the exact relative location of which can often be ascertained by preinsertion digital exploration. One might consider antotransfusing fresh hemothorax blood using an appropriate device.
INDICATIONS FOR THORACOTOMY FOLLOWING TRAUMA
Only approximately 15% of patients with chest injury require a formal thoracotomy. The indications for thoracotomy continue to change as newer, noninvasive therapies such as endovascular removal of intravascular foreign bodies and endovascular stent graft insertions become available. Although many different injury patterns may occur in the chest and to its contents, indications for an acute formal thoracotomy follow both anatomic and physiologic parameters and include:
• Loss of chest wall substance (traumatic thoracotomy)
• Traumatic hemopericardium8
• Evidence of free wall, septal, or valvular cardiac disruption8
• Radiologic or endoscopic evidence of tracheal, bronchial, esophageal, or great vessel injury9,10
• Greater than 1500 mL blood loss from the pleural cavity following the initial tube thoracostomy11
• Greater than a sustained 200 mL continuing blood loss per hour from the tube thoracostomy
• Loss of cardiac function or proximal vascular control (resuscitative thoracotomy)9,12–15
• Massive air leak
• Demonstrable thoracic tracheal or bronchus injury
• Uncontrolled hemorrhage in thoracic outlet major injury
• Mediastinal missile traverse with massive blood or air loss through the chest tube
• Removal of selective foreign bodies
• Massive air embolism, particularly systemic air embolism
• Retained clotted hemothorax (subacute and chronic indications)16
• Posttraumatic contained empyema16
• Cardiac herniation (ruptured pericardium)17
• Cardiac septal or valve disruption
MINOR THERAPEUTIC INTERVENTIONS
In addition to the routine basic maneuvers to stabilize the trauma patient, a number of minor therapeutic interventions are available. Some, such as needle decompression of the pleural cavity, pericardiocentesis, interosseous sternal fluid infusions, and subxyphoid pericardiotomy, have been controversial with regard to specific indications and the ultimate expected benefit. Specific, evidence-based data are not sufficient to recommend these maneuvers. Other minor thoracic maneuvers used by the surgeon include:
• Endotracheal intubation (limiting the ventilatory pressures to less than 40 TORR in order to prevent systemic air embolism
• Intercostal tube thoracostomy
• Video-assisted thoracic surgery (VATS)
• Intercostal and epidural block for pain control
• Digital thoracotomy (gentle digital exploration to the extent of the inserted finger at the time of tube thoracostomy)
The supine position is the utility position for operations on thoracic trauma patients, as it allows for a variety of anterior incisions, including median sternotomy, right and or left anterolateral thoracotomy, transternal bilateral anterolateral thoracotomy, and partial anterior incisions (Fig. 24-1).
FIGURE 24-1 Thoracic incisions for trauma include (A) median sternotomy, (B) book thoracotomy, (C) posterolateral thoracotomy, (D) anterolateral thoracotomy, and (E) extension of an anterolateral thoracotomy across the sternum. (Reproduced with permission from Baylor College of Medicine.)
Approaches to the posterior mediastinum and, at times, the hilum of the lung following trauma are via either a right or left posterolateral thoracotomy through a carefully chosen interspace. This position and these incisions are best suited for injury to the descending thoracic aorta, esophagus, azygous vein, and the mediastinal trachea and bronchi. If, for whatever reason, the initial approach was via an anterior incision but a predominately posterior injury is found, the anterior incision should be closed, and the patient reopened via a position and incision that optimizes exposure and management of the injury (Figs. 24-2 and 24-3).
FIGURE 24-2 Incision algorithm.
FIGURE 24-3 Specific injuries algorithm.
In the past, one indication for thoracotomy following trauma was presence of a thoracoabdominal injury, and a thoracoabdominal incision across the costal margin was recommended. Neither this indication nor this incision is now considered standard and use creates more difficulty in exposure as well as complications than the more standard incisions.5,6 It is more appropriate to approach injuries in multiple cavities as if an injury were isolated to only one cavity, and enter the cavity with the most apparent complex injury first.
THORACIC DAMAGE CONTROL
Damage control tactics were among the most important advances in trauma management during the 1990s. Packing an area inside the chest does not have the same damage control utility as such tactics have in the abdomen. Damage control tactics for the patient with thoracic trauma will be cited in other chapters of this book and include:
• Emergency room thoracotomy and resuscitation9,12–15
• Pulmonary tractotomy18
• Pulmonary hilar twist19
• Endovascular hemorrhage control (emerging)10
• Temporary damage control thoracic closure
THORACIC TRAUMA CONTROVERSIES
In evaluating and treating patients with thoracic trauma, it is important to recognize that some of the historic approaches are both controversial and lacking in scientific evidence, despite wide popular use.
Controversies in CT Scanning
CT scanning has provided many areas of human pathology with a very focused specific image of altered anatomy and is widely used in trauma, particularly blunt trauma. As a screening modality, it joins the plain chest x-rays in assisting the clinician. For missile traverse of the mediastinum, the CT scan provides a trajectory tract to aid in determining the need for other diagnostic tests. In vascular injury, the CT scan joins classic arteriography to demonstrate direct and indirect trauma. For some areas of vascular evaluation, the CT angiogram and the computerized reconstructions demonstrate both specific and nonspecific changes, but the CT scan and CTA have also caused confusion and often beg the need for additional more diagnostic tests, such as a classic arteriogram. As an example, most of the supportive literature on CT scanning for the thoracic aorta has been limited to the area of the proximal descending thoracic aorta. In addition, literature is emerging to raise concerns about the amount of radiation exposure for patients.20–22 Numerous different CT and CTA protocols exist, depending on the possible injury as well as the specific organ to be imaged. With the greater sophistication of CT and MR imaging, it becomes increasingly important for the clinician to understand these differences. Because of motion artifact, CTA of the thoracic aorta is not well suited for the ascending aorta, unless the newer ECG-gated synchronization is available.
Virtually every resuscitation course teaches and recommends the technique of pericardiocentesis to relieve hemopericardium and cardiac tamponade following injury. Trauma surgeons routinely describe clotted blood between the pericardium and heart at emergency thoracotomy for hemopericardium. Pericardial fluid aspiration that is successful for nonclotting fluid has not been proven to be as successful during the acute time interval following injury. Additionally, surgeons often describe iatrogenic cardiac penetration following an attempted pericardiocentesis for acute trauma. Pericardiocentesis for acute hemopericardium has not been a beneficial procedure. For such cases, emergency thoracotomy, pericardiotomy, and cardiorrhaphy are indicated.
A subxyphoid pericardiotomy, often performed in the emergency room or operating room to detect hemopericardium, was introduced as a technique prior to the wide adaptation of the Focused Abdominal Sonographic (examination) for Trauma (FAST), and CT scanning was widely accepted for the evaluation of patients who might have a hemopericardium. This rather small abdominal incision would allow for direct drainage of pericardiac blood but would allow for no focused cardiorrhaphy. With more precise diagnostic techniques for pericardial fluid, a directed thoracic incision could be used to expedite relief of pericardial tamponade and repair any cardiac injury. It is logical to apply a thoracic incision to a thoracic injury when an open procedure is indicated.
Needle Decompression of Pleural Cavity
Historically, a tension pneumothorax following thoracic trauma was believed to account for significant numbers of deaths in both prehospital and emergency room phases of evaluation and treatment. Insertion of a “decompressing” needle into the pleural cavity has been recommended in many of the resuscitation courses, despite any controlled studies to demonstrate the exact frequency of tension pneumothorax or the specific benefit or utility of needle decompression. Furthermore, tension pneumothorax is undoubtedly more difficult to determine than has been presumed, particularly in a moving ambulance. In patients without a pneumothorax or with a pleural symphysis, insertion of a large-bore needle into the lung in an intubated patient can contribute to fatal systemic air embolism and also cause a pulmonary hematoma with subsequent pulmonary insufficiency.
Trocar Chest Tubes
Up to 25% of the population has some degree of pleural symphysis between the visceral and parietal pleura secondary to some earlier infection or inflammation. Consequently, it is recommended that following the skin and muscle incisions for a tube thoracostomy, the pleura be entered with the exploring finger rather than an instrument. If percutaneously inserted, the commercially available chest tube device with a Trocar-tipped metal rod in the middle of the chest tube has the potential for causing an iatrogenic injury (stab) to the lung or other thoracic or upper abdominal organs as it is forcefully pushed into the body.
Clamping of Chest Tubes
Large-bore chest tubes enhance drainage of blood, fluids, air, purulent material, and the like from the pleural cavity. Chest tubes are widely used for both penetrating and blunt thoracic trauma with concomitant pneumothorax or hemothorax, or both. An appropriately placed chest tube often precludes the need for a formal thoracotomy and should prevent retained clotted hemothorax. The chest tube is connected to a pleural drainage system. Once the pathology that necessitated chest tube insertion has resolved, the tube is removed. With a clear understanding of pleural anatomy and physiology, complications at chest tube removal are rare. Some clinicians involved in the care of trauma patients recommend that chest tubes be clamped prior to removal to assure appropriate timing of removal. This recommendation falls more into the “urban legend” category than evidence-based good practice and is not recommended by these authors.
Pledgets in Cardiorrhaphy
Cardiorrhaphy is routinely accomplished during cardiac surgery without the use of adjunctive pledgets in the suture line. Although often used during posttraumatic cardiorrhaphy, this practice is not supported by experience and introduces an unnecessary added step for the surgeon and operating room nurse.
Trap Door Thoracotomy
This combined anterolateral, partial sternotomy, and supraclavicular (“trapdoor” or “book”) incision that was popular in the 1970s for injuries to the left thoracic outlet but offers little exposure advantage and is very morbid. In the current endovascular era, proximal vascular control can be obtained with an intravascular balloon, followed by either endovascular repair or open repair via a supraclavicular incision.
TIMING OF THORACOTOMY
Timing of an acute thoracotomy is a function of the immediacy of the life-threatening condition.23 Following injury to the chest, potentially life-threatening conditions include acute pericardial tamponade, acute and massive blood loss, disruption of ventilatory function, and decreased cardiac output. These conditions are the basis for the traditional A-irway, B-reathing, C-irculation of resuscitation. Infection, sepsis, pulmonary insufficiency, and other functional impairments may occur secondarily, and any or all contribute to the decision to operate and when.
• Immediate and Emergent: Immediate thoracotomy is usually performed either in the emergency center or in an operating room immediately available to the emergency center. For an acute injury to the heart and immediate loss of cardiac output from reversible conditions of pericardial tamponade, cardiac herniation, cardiac rupture, or a posttraumatic cardiac arrhythmia, immediate thoracotomy is performed by a knowledgeable and qualified physician. Patients with posttraumatic prehospital external cardiac massage for more than 5-10 minutes are unlikely to be resuscitated in the hospital, even with an emergency center thoracotomy. However, when the team determines a need for an EC thoracotomy, such procedures can be individualized and tracked by the hospital’s quality review process.
• Urgent: An urgent thoracotomy is performed minutes to hours after injury to control and manage a potentially life-threatening condition or prevent the development of further deterioration, injury or infection.
• Delayed: Delayed posttraumatic thoracotomy is performed for one of two conditions. In a patient with multisystem trauma, delayed repair of an injured but controlled aortic injury may occur to allow time for stabilization or treatment of a severe lung, pelvis, or head injury. Alternatively, thoracotomy for evacuation of a clotted hemothorax, management of a late presenting complication or previously missed injury may be delayed. In the chest, as elsewhere in the body, following significant trauma, staged procedures are part of current approach to management.
Tube thoracostomy is the most common procedure following thoracic injury. However, a clotted hemothorax is not always completely evacuated with a chest tube alone. When a clotted hemothorax persists, VATS or thoracotomy should be used to evacuate it as soon as possible, even within 2 days of discovery. Early evacuation reduces the incidence of posttraumatic empyema. Every hospital’s trauma program can profit from a protocol to address this common complication, and, as such, can be followed as a performance improvement indicator.
COMPLICATIONS OF THORACIC TRAUMA EVALUATION AND TREATMENT
The heart, great vessels, pleural cavity, and lungs each have a limited number of ways to respond to under- and overtreatment and related complications. Many of these specific complications will be cited and discussed in the organ-specific injury chapters. For completeness, a few of these complications are briefly cited here.
• Fluid Overload and ARDS: Recognized for decades but specifically codified during the Vietnam War, fluid overload and the resultant adult respiratory distress syndrome have been increasingly described and better understood during the past 20 years. The ability for various crystalloids to activate inflammatory mediators, as well as contribute to ARDS, is now well described, resulting in the current wave of crystalloid restriction during the resuscitative phase of trauma. It is also well recognized that the contused lung is more prone to barotrauma, pneumonia, and fluid overload than is the uninjured lung.
• Barotrauma: Although “high” positive end-expiratory pressure (PEEP) was used for patients with posttraumatic respiratory insufficiency during the 1970s, it is now recognized that high inspiratory pressures and other ventilatory forces cause an undesirable constellation of volutrauma/barotrauma to both the bronchial lining and the interstitium.
• Systemic Air Embolism: Vascular air embolism can affect venous return to the heart and the right cardiac circulation, as well as cause pulmonary venous air embolism, which becomes systemic air embolism. Both are most often iatrogenic, with systemic air embolism being secondary to lung injury under conditions of increased endobronchial pressures greater than 40 TORR. With needle, bullet, knife, or Trocar injury to the lung in an intubated patient in an ambulance, EC, OR, or ICU, air may be forced at the area of the injury from bronchioles to the pulmonary venules. From there, air can go to the left atrium, producing systemic air embolism, seizures, and ventricular fibrillation because of air in the coronary and cerebral arteries. It is preventable, but when it does occur, it is almost always fatal.
• Aspiration: Although aspiration into the lung is not uncommon following trauma, many of the resuscitative efforts in the EMS, EC, Radiology, and the OR may contribute to aspiration and some of its more undesirable side effects. The insertion of a nasogastric or feeding tube into the pharynx of a fully awake patient with a stomach full of food is conducive to aspiration of vomited gastric contents. Aspiration of water-soluble contrast material, such as gastrograffin, into the lungs produces a chemical pneumonia much more severe than that produced by aspiration of a barium-based contrast material. The insertion of a feeding tube into the bronchus, lung substance, or even the pleural cavity, and then subsequent insertion of feeding material into the lung or pleura produces devastating results. Aspiration is best treated by bronchoscopy to remove solid particles.
• Radiation Exposure: Primary, emergency, trauma, and consulting physicians all have a growing appetite for ordering increasing numbers of complex imaging studies. Overutilization of CT scanning and vascular contrast material has resulted in significant doses of radiation, greater than during the acute evaluation of a trauma patient just two decades ago. Controversy persists on number of studies ordered, necessity, and duplication, as well as the maximum radiation dosages that patients can tolerate. Unfortunately, quality review of medical records rarely reveals a pre-imaging progress note indicating why the test was ordered, what the clinician wanted to learn from the study, or how results of image might alter decision-making. Such progress notes undoubtedly would be beneficial in defending excessive radiation, which might have resulted in a radiation associated problem, such as a lymphoma or leukemia.20–22
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