Critical Decisions in the Management of Thoracic Trauma




Traumatic injuries to the thorax are common after both blunt and penetrating trauma. Emergency medicine physicians must be able to manage the initial resuscitation and diagnostic workup of these patients. This involves familiarity with a range of radiologic investigations and invasive bedside procedures, including resuscitative thoracotomy. This knowledge is critical to allow for rapid decision making when life-threatening injuries are encountered. This article explores the initial resuscitation and assessment of patients after thoracic trauma, discusses available imaging modalities, reviews frequently performed procedures, and provides an overview of the indications for operative intervention, while emphasizing the critical decision making throughout.


Key points








  • Every trauma patient should undergo a rapid clinical examination to screen for traumatic injuries to the thorax.



  • There are several imaging modalities that should be considered in the emergency department, which include ultrasound, plain radiographs, and computed tomography scan. It is important to be aware of the indications and pitfalls of each.



  • Many thoracic injuries can be managed nonoperatively. Invasive bedside procedures, such as chest tube placement, are critical skills for all emergency medicine physicians who treat trauma patients.



  • Resuscitative thoracotomy is a procedure that should be familiar to the emergency medicine physician and is indicated for select patients following penetrating and blunt trauma.






Introduction


The initial assessment of any injured patient must proceed expeditiously and in a systematic fashion. Injuries to the thorax are common after both blunt and penetrating trauma and, therefore, all patients who present to the emergency department (ED) after trauma should be screened for thoracic injury according to the Advanced Trauma Life Support (ATLS) protocol. Because chest injury can impact each of the ABCs (Airway, Breathing, and Circulation), a rapid evaluation of the chest is performed early in the evaluation of the injured patient to look for any life-threatening injuries. Non–life-threatening injuries to the thorax are detected as part of the detailed secondary survey.




Introduction


The initial assessment of any injured patient must proceed expeditiously and in a systematic fashion. Injuries to the thorax are common after both blunt and penetrating trauma and, therefore, all patients who present to the emergency department (ED) after trauma should be screened for thoracic injury according to the Advanced Trauma Life Support (ATLS) protocol. Because chest injury can impact each of the ABCs (Airway, Breathing, and Circulation), a rapid evaluation of the chest is performed early in the evaluation of the injured patient to look for any life-threatening injuries. Non–life-threatening injuries to the thorax are detected as part of the detailed secondary survey.




How do I manage life-threatening thoracic injuries?


In the thorax, immediately life-threatening injuries include tension pneumothorax, massive hemothorax, open pneumothorax from a chest wall defect, and cardiac or great vessel injury. These injuries and their management in the ED are reviewed here.




Decompressing the chest in a hypotensive patient with thoracic trauma


Although shock in the trauma patient is hemorrhagic until proven otherwise, consideration of a tension pneumothorax should occur with any hypotensive trauma patient. The practical clinical findings associated with tension pneumothoraces include hypotension and tachycardia with poor oxygenation. The classically described absent ipsilateral breath sounds can be difficult to detect in the noisy, chaotic trauma bay, and tracheal deviation may be missed if a cervical collar is in place. Therefore, clinical suspicion should remain high even when breath sounds are equivocal.


If a tension pneumothorax is suspected, the chest should be rapidly decompressed. A chest radiograph (CXR) is unnecessary and potentially harmful if it delays intervention. An ultrasound probe, if readily available in the trauma bay, can be placed on the chest to assess lung sliding, the absence of which is suggestive of pneumothorax. However, tension pneumothorax is a clinical diagnosis, and the clinician should not wait for radiographic confirmation before intervening.


In the classic description of needle decompression, a large-bore angiocatheter is placed into the pleural space at the second intercostal space in the midclavicular line (2IC/MCL). More contemporarily, the fifth intercostal space at the anterior axillary line has been found to yield greater success rates because of decreased chest wall thickness at that site. Needle decompression may fail in up to 58% of cases when performed at the 2IC/MCL position. Because of this, needle decompression as a means to treat tension pneumothorax should be limited to settings in which finger thoracostomy or chest tube placement is not feasible.


The first portion of tube thoracostomy, in which decompression of the pleural space is achieved by opening the parietal pleura and confirming entry by inserting a finger into the pleural space (referred to by some as a finger thoracostomy), is a better and more reliable means for decompressing the thorax. A scalpel is used to make a 2-cm to 3-cm skin incision in the fourth or fifth intercostal space in the anterior axillary line and then is used to cut through the subcutaneous fat and intercostal muscle. A small cut is made in the pleura and the physician’s finger is then used to widen the opening into the pleural space, thereby decompressing the chest. This should take mere seconds to perform and should be followed up with the insertion of a chest tube through the aperture as soon as time and the patient’s condition permit. The clinician will know the pleural space has been entered with the evacuation of a gush of air or blood, and the patient’s hemodynamics should normalize accordingly. If they do not, another etiology for the patient’s altered physiology must immediately be considered. Entering the pleural space under direct visualization with digital confirmation provides visual and tactile feedback that the pleural space has been decompressed. This is not true for needle decompression, in which the absence of air return may simply be a result of the catheter becoming kinked, blocked, or malpositioned.


Which Patients Require Tube Thoracostomy?


Pneumothoraces and hemothoraces causing respiratory or circulatory compromise require drainage by way of chest tube connected to a closed suction system and underwater seal. A large hemothorax can present with absent breath sounds, poor oxygenation, or hypotension, but is more typically detected on supine CXR by visualizing a layered opacity throughout the hemithorax, with point-of-care ultrasound demonstrating a pleural effusion, or by way of finger thoracostomy during the primary survey.


Not every patient with a pneumothorax or hemothorax needs a chest tube. Most hemothoraces should be drained with tube thoracostomy because of the risk of developing empyema or fibrothorax, although diminutive hemothoraces can be left undrained. Patients with an asymptomatic pneumothorax clearly visible on CXR and any symptomatic pneumothoraces, including those with signs of tension pneumothorax, should have a chest tube placed. Patients with an occult pneumothorax, identified on computed tomography (CT) of the chest but not seen on CXR, likely do not require tube thoracostomy if the pneumothorax is stable and asymptomatic. The Eastern Association for the Surgery of Trauma (EAST) Practice Management Guidelines support this approach even if the patient undergoes positive pressure ventilation. In other words, occult pneumothoraces seldom progress to tension physiology, even with mechanical ventilation. Indications for delayed chest tube placement in patients with traumatic occult pneumothoraces are poorly defined but could reasonably include pneumothoraces that become visible on follow-up CXR and patients who become symptomatic.


A chest wall defect causing an open pneumothorax also requires rapid chest tube placement. The chest wall defect, usually obvious on clinical examination, can cause tension pathophysiology and circulatory collapse. An occlusive dressing taped on 3 sides should be placed to cover the defect and a tube thoracostomy should quickly follow.


Chest Tube Insertion


Inserting a chest tube requires a scalpel, 2 Kelly clamps, the chest tube itself, a needle driver, suture (usually 0 silk), scissors, and an underwater seal system. Using sterile technique, the fourth or fifth intercostal space is identified as the site for chest tube insertion in the anterior axillary line. The appropriate location can be approximated by the intercostal space in line with the nipple. The chest should be prepped widely to landmark the axilla, sternal border, and costal margin. Especially in the awake patient, generous infiltration of local anesthetic, including to the rib periosteum and parietal pleura, is critical. The skin incision, approximately 2 to 3 cm in length, is typically oriented in a transverse direction and a Kelly clamp is then used to spread the subcutaneous tissue and intercostal muscle. The pleura should be entered just above the superior border of the rib below to avoid the neurovascular bundle traveling along the costal groove inferiorly in the rib above. In young patients, entry into the pleural space can require a significant amount of force; it is important to brace the hand advancing the Kelly clamp with the opposite hand against the chest wall, to halt overzealous entry into the thorax when the pleura is punctured. The opening into the pleura is then widened by spreading the Kelly, and a finger is inserted next to confirm entry into the pleural space and ensure the lung is not adherent to the chest wall at that site. A chest tube is then guided into the pleural space with the physician’s finger. Care should be taken to ensure the distal-most drainage hole is within the pleural space, a distance that can be approximated by inserting the chest tube a hand’s width farther into the chest than the last drainage hole. The tube is then sutured in place and connected to underwater seal and wall suction at −20 cm H20.


Does Size Matter?


Traditionally, the insertion of large-bore chest tubes (≥36 Fr) was advocated for traumatic hemothoraces and pneumothoraces. More recently, clinicians have moved toward the placement of smaller chest tubes. One study compared the use of 28 to 32-Fr with 36 to 40-Fr chest tubes in trauma and found no difference in the successful evacuation of hemothoraces or pneumothoraces with smaller-bore chest tubes. One article argued that chest tubes as small as 14 Fr can successfully drain hemothoraces among stable trauma patients, but further confirmation of these findings is required before chest tubes this small are adopted into widespread practice. At our institution, 28-Fr chest tubes are used in most trauma patients requiring tube thoracostomy.




Cardiac tamponade leading to traumatic arrest


Traumatic cardiac tamponade occurs almost exclusively after penetrating injuries to the chest. Blunt cardiac injury causing free wall rupture and tamponade is exceedingly rare and usually catastrophic. Patients with cardiac tamponade are deceptively stable at first, but can deteriorate rapidly and are exquisitely sensitive to routine resuscitation interventions, such as volume resuscitation, sedation, and positive pressure ventilation. Because these patients are normotensive until they arrest, clinical suspicion of tamponade must be high after penetrating injuries to the thorax.


Pericardiocentesis is an optional technique taught by ATLS for decompressing cardiac tamponade. Once a staple of diagnosis and management, the diagnostic component of pericardiocentesis has been supplanted by the pericardial view in Focused Assessment with Sonography for Trauma (FAST). The therapeutic capacity of pericardiocentesis is now emphasized as a temporizing measure when cardiac tamponade is present but a surgeon with the capacity to fix a cardiac injury is not. If a surgeon is available and the patient has vital signs, time should not be wasted attempting a pericardiocentesis in the trauma bay; the patient should instead be transported emergently to the operating room (OR) for median sternotomy and cardiac repair. Pericardiocentesis thus has only a very limited role as a temporizing measure when cardiac tamponade is identified on FAST, but the patient requires transfer to a surgical center before definitive repair. If the patient loses vital signs, a resuscitative thoracotomy should be performed.


The Ultimate Emergency Room “Procedure”: Resuscitative Thoracotomy


The indications for resuscitative thoracotomy (RT) are controversial. Resuscitation after a traumatic cardiac arrest is a blood product–intensive and resource-intensive undertaking, and if no one is available to surgically halt the bleeding that induced the arrest, opening the chest will be a uniformly fatal procedure. Conversely, not performing an RT when it is indicated carries a 100% mortality. Although RT should not be restricted to trauma centers, patients who present to an ED with a very limited blood bank or lacking surgical or intensive care unit support should not undergo RT, as outcomes are likely to be very poor.


Survival after RT is variable. In the largest systematic review of outcomes (n = 4620), overall survival was 7.4%. In this 25-year review, the 3 key predictors of survival after RT were anatomic location of the injury (highest among cardiac injuries, 19.4% survival), mechanism of injury (highest after penetrating trauma, 8.8% survival), and signs of life on arrival to ED (11.5% survival). In some practice settings, ultrasound also may be used to decide who should undergo this procedure. A prospective study showed that arrested patients without cardiac motion or pericardial fluid on FAST died uniformly (negative predictive value 100%). The positive predictive value of cardiac motion on FAST, defined in the study as organized, nonfibrillating contractions, was 16.7%. If ultrasound is used, the absence of cardiac motion and pericardial fluid can be used to avoid initiating this procedure, as the survival is extremely low.


Both the EAST and the Western Trauma Association (WTA) have published guidelines about the indications for RT. The EAST guidelines are centered around signs of life, defined by the American College of Surgeons Committee on Trauma as any of the following: pupillary response, respiratory effort, palpable carotid pulse, measurable or palpable blood pressure, extremity movement, or cardiac electrical activity. EAST strongly endorses RT for patients with penetrating thoracic trauma who arrive pulseless to the ED but show signs of life. For patients with penetrating thoracic trauma who present without signs of life, patients with penetrating extrathoracic trauma with or without signs of life, and patients with blunt trauma and signs of life, EAST conditionally recommends RT. RT is not recommended for patients who present pulseless after blunt injury, without signs of life. WTA, on the other hand, stratifies patients first according to duration of cardiac arrest. For blunt traumatic arrests with less than 10 minutes of cardiopulmonary resuscitation (CPR) and penetrating traumatic arrests with less than 15 minutes of CPR, RT is considered beneficial. WTA also supports RT for longer durations of arrest if signs of life (respiratory or motor effort, electrical activity, or pupillary activity) are present.


In summary, deciding which patients are candidates for RT requires integrating information on the mechanism and anatomic location of injury, duration of cardiac arrest, presence or absence of signs of life, findings on bedside ultrasound, and the available resources and personnel. At our institution, we are liberal with the indications for RT and perform it on all patients with traumatic cardiac arrest after penetrating trauma, as well as most patients who arrest after blunt trauma. We do not use ultrasound routinely to select candidates for the procedure, but use it selectively in arrested patients with blunt trauma if they have had a prolonged down time to identify patients who are unlikely to survive.


How Do I Perform a Resuscitative Thoracotomy?


The goals of an RT are to release pericardial tamponade, control intrathoracic hemorrhage, apply an aortic cross-clamp, and perform internal cardiac massage. Very infrequently, an air embolism may be evacuated from the left ventricle by way of needle aspiration. When resources permit, the patient’s airway should be secured, a right-sided chest tube should be placed, and intravenous access should be obtained concurrently with RT.


To perform a left anterolateral thoracotomy, the first step in RT, a skin incision is made boldly in the fifth intercostal space, approximated by the rib space below the nipple in men and in the inframammary fold in women, starting from the midline and curving upward toward the axilla to follow the curvature of the ribs, all the way down to the stretcher. The subcutaneous fat, chest wall musculature, and intercostal muscle are incised sharply with a scalpel. The intercostal muscle and underlying parietal pleura can be divided en masse with scissors, if preferred, which will decrease the chances of iatrogenic lung injury on entering the chest.


After entering the chest, a Finochetto retractor is used to spread the ribs and the lung is retracted superiorly and posteriorly to allow visualization of the pericardium. The pericardium is opened anterior and parallel to the phrenic nerve, and the heart is then delivered and inspected for injury. Any lacerations are repaired using a 2.0 prolene suture. The left hemithorax is inspected for any other signs of bleeding; for example, from the lung, intercostal vessels, or pulmonary hilum. An aortic cross-clamp is applied after first identifying the aorta just above the diaphragm as the structure immediately anterior to the vertebral bodies, and opening the mediastinal pleura bluntly with a finger anteriorly and posteriorly to the aorta to allow secure clamp placement. Internal cardiac massage is then performed using 2 hands with compression initiated at the cardiac apex. Intracardiac medication delivery, such as 1 mg of epinephrine into the left ventricle, and defibrillation are initiated as warranted. Evacuation of blood from the right chest tube should prompt extension into a clamshell thoracotomy. Additionally, if a cardiac injury is discovered and visualization is poor through the left anterolateral thoracotomy, the physician should not hesitate to extend the incision across the midline and into the right chest as a clamshell thoracotomy to facilitate repair. A complete description of the procedural approach to RT can be found elsewhere.







  • Finding Yourself Face to Face with an Opened Chest: What to Do Once You’re In



  • Open the pericardium and deliver the heart. Check for and repair any cardiac injuries.



  • Stop any major intrathoracic bleeding.



  • Cross-clamp the aorta just above the diaphragm.



  • Begin open cardiac massage and resuscitation.



  • Inject intracardiac epinephrine into the left ventricle.



  • Extend into a clamshell thoracotomy if there is blood in the right chest.


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Dec 1, 2017 | Posted by in Uncategorized | Comments Off on Critical Decisions in the Management of Thoracic Trauma
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