Cardiac Trauma – Blunt and Penetrating
May 16, 2022 - read ≈ 14 min
Thais Faggion Vinholo, MD, MSc
Division of Cardiac Surgery, Brigham & Women’s Hospital, Boston, MA, USA
Antonia Kreso, MD, PhD
Division of Cardiac Surgery, Massachusetts General Hospital, Boston, MA, USA
Serguei Melnitchouk, MD, MPH
Division of Cardiac Surgery, Massachusetts General Hospital, Boston, MA, USA
Traumatic injury to the heart can occur due to either penetrating or blunt force. Penetrating trauma is mostly due to gunshot or stab wounds to the chest. It usually results in injury to the right ventricle, right atrium, or left ventricle, but can also involve the left atrium, interventricular septum, valves, or coronaries. Most patients with gunshot wounds to the heart die before reaching the hospital. Cardiac stab wounds can cause tamponade and have a higher chance of survival if the patient arrives to the hospital still alive. Hence, resuscitative thoracotomy in the setting of a penetrating trauma can be lifesaving, even if performed in the trauma bay of the emergency room.
Blunt cardiac injury is mostly caused by motor vehicle crashes, pedestrian struck by motor vehicles, and falls from heights. Exertions of blunt force to the chest can result in myocardial contusion, coronary dissection, rupture of the pericardium leading to cardiac herniation or torsion, rupture of a cardiac chamber, valve tear, pulmonary vein avulsion, and other injuries. Resuscitative thoracotomy is likely futile in the setting of blunt cardiac trauma as the vast majority of cases result in death of the patient. Therefore, there is no indication for a resuscitative thoracotomy if a patient arrives to the hospital without vital signs following a blunt trauma. On that note, after blunt chest trauma, a patient who has clear evidence of significant pericardial fluid as evidenced by a focused assessment with sonography in trauma (FAST) examination should be immediately transferred to the operating room to rule out significant injuries to the heart or great vessels. If available on site, mobilization of cardiac surgical and perfusionist teams can be helpful, especially if cardiopulmonary bypass is needed to repair a life-threatening cardiac injury, such as pulmonary veins avulsion.
II. Clinical Presentation
Patients with injuries to the heart can present in a variety of ways, ranging from hemodynamic stability to extremis and cardiac arrest. Hemodynamic instability may result due to hemorrhage, cardiac tamponade, or acute pump failure secondary to various intra- or extracardiac injuries. Although tamponade is mainly seen in penetrating trauma, it can also be present from blunt trauma. Special consideration should be given to the fact that Beck’s triad (jugular venous distention, hypotension, and muffled heart sounds) is seen in only one-third of patients with tamponade(1).
A patient with a suspected cardiac injury should be evaluated in an organized and expeditious manner, focusing on the primary survey. ABCDEs involve assessment of the airway, breathing, circulation (including obtaining vascular access), disability (Glasgow coma scale), environment, and exposure. As part of the survey a FAST examination should be performed. FAST is sensitive at identifying fluid within the pericardial sac, which can be concerning for hemopericardium in the setting of trauma (Figure 1). To obtain the subxiphoid view, the transducer is placed in the subxiphoid position pointing towards the heart with the transducer notch to the left side of the patient. This will allow evaluation for fluid around the heart. One may consider downloading a freely available application such as “FAST Heart,” which can be used as a bedside assistant to validate appropriate views and aid in diagnosis of common pathologies.
If there is suspicion for penetrating cardiac injury with ongoing hemodynamic instability, patients should receive rapid fluid resuscitation and proceed to the operating room immediately, minimizing time spent on additional work up.
EKG and chest x-ray should be obtained for all patients with stable vital signs and if they are not being rushed to the OR. Blunt trauma should be suspected with EKG changes, including arrhythmias and sinus tachycardia. A normal EKG has a high negative predictive value (approaches 98%) for cardiac injury. Troponin or other cardiac enzymes should also be obtained. If the patient is hemodynamically stable, CT chest can be considered. Given the high cost and limited resources, CT can be reserved to cases where there is evidence for penetrating objects crossing the chest or when there is concern for esophageal, tracheobronchial, or vascular injury.
In addition to the cardiac chambers and great vessels, injury to other neighboring structures such as trachea or esophagus must be considered during chest injury. A comprehensive exam should be performed to rule out presence of subcutaneous emphysema which could indicate manifestation of such injury. Lastly, as in any trauma patient, it is important to complete a thorough secondary survey and rule out injury to other organ systems.
As with any other trauma patient, two large bore intravenous lines should be inserted. For monitoring, a urinary catheter with bladder thermistor, arterial catheter, and central venous catheter should be used in addition to the routine pulse oximeter, end tidal CO2, continuous electrocardiogram, and a temperature measurement device. A couple units of packed red blood cells should be crossmatched in case there is need intraoperatively.
In the operating room, the patient should be prepped and draped awake prior to the induction of anesthesia. This should be done to stay prepared in case the remaining sympathetic tone is lost with a resultant hemodynamic collapse due to anesthesia induced vasodilation. In such instances, one needs to be ready to perform an expeditious median sternotomy or pericardial window.
A pericardial window should be considered when patients present with positive FAST or high suspicion for tamponade physiology while having equivocal ultrasound windows or when ultrasound is not available at all(4). If possible, the window should be performed in the operating room. With a knife, a midline incision is made over and just inferior to the xiphoid process. The xiphoid process can be excised with scissors if needed for better exposure of the pericardium. The pericardium is identified using blunt dissection, keeping the diaphragm inferior. The pericardium is then grasped with two Kocher clamps (or two Aliss clamps) and incised with scissors between the clamps. If upon entering the pericardium blood is obtained and persistent bleeding is suspected, one should convert to a full median sternotomy for chest exploration(5). If the exploration yields a negative result (lack of blood or persistent bleeding), the incision can be closed over a drain, which should be left in place to monitor for ongoing bleeding.
Anterolateral thoracotomy and clamshell approaches
If a patient with a penetrating cardiac injury loses vital signs in the trauma bay, one should quickly proceed with an anterolateral thoracotomy. Timing is critical and the following should be gathered quickly (in addition to having sterile gown and gloves): betadine, scalpel with No. 10 blade, trauma scissors, and rib spreader.
The patient is positioned supine with arms extended to the side. With a knife an incision is made at the level of either fourth or fifth intercostal space, which roughly corresponds to the inframammary crease. The intercostal space is subsequently opened with trauma scissors cutting the intercostal muscles and pleura in an anterior-to-posterior fashion in one swing without much delay in time. One should stay on top of the rib to avoid injury of the intercostal neurovascular bundle. If available, a rib spreader is used to facilitate exposure, otherwise an assistant spreads the intercostal space manually until the pericardium is opened.
Once inside the chest, the lung is swept out of the way, the phrenic nerve is identified, and a scalpel is used to incise the pericardium. The pericardial incision is then extended with scissors above and parallel to the phrenic nerve, which must be preserved. The right-sided phrenic nerve courses on the surface of the pericardium anterior to the pulmonary hilum while the left-sided runs over the middle of the pericardial surface and tends to come even more anteriorly as it approaches the left diaphragm. Once the pericardium is widely opened and pericardial tamponade is relieved, one should immediately start with direct cardiac massage. Descending aorta might need to be cross-clamped temporarily in order to have sufficient blood volume for cardiac and cerebral perfusion until one catches up with volume resuscitation.
If there is concern of injury to the right hilum or right sided heart structures, the left anterolateral thoracotomy can be easily extended to a full clamshell incision. In that case, both mammary arteries are sacrificed and ligated, and the sternum is divided with either an oscillating saw, Gigli saw, or a Lebsche knife. With this maneuver the incision is carried over the sternum into the contralateral intercostal space and the trauma surgeon has full access to all structures in the chest.
If the patient re-gains vital signs following a resuscitative thoracotomy and relief of tamponade in the emergency department, the patient should be transferred to the operating room for further definitive evaluation of the chest cavity.
Median sternotomy approach
Median sternotomy is usually reserved for hemodynamically stable patients(6) who require chest exploration for trauma. The benefit of such an approach is exposure, easy access to the bilateral pleural spaces, and the possibility of extending the incision to a laparotomy. The patient is positioned supine with arms positioned on the arm boards laterally. Using a scalpel with a No. 10 blade, the sternotomy incision is performed from the sternal notch to the xiphoid process. The incision is carried down to the sternum with cautery while taking care to avoid the brachiocephalic vein, which crosses the midline posterior to the sternal notch. The second intercostal space is the narrowest part of the sternum, and one should strive to stay in the middle of the sternum. Anesthesia should hold ventilation during sternal division with an oscillating saw or a Lebsche knife. Once the chest is opened, stay sutures can be placed in the pericardium to elevate the heart to aid in exposure. Several operative techniques (outlined below) can be employed depending on the injury encountered.
Regardless of the incision, the operative objectives are the same: relieve tamponade, stop bleeding, and restore circulating volume. Primary cardiac repairs are best performed using double-loaded polypropylene suture on a cardiovascular needle. Atrial injuries are repaired with interrupted or running horizontal mattress sutures using a 3-0 or 4-0 polyprolene suture. One might need to use felt strip or autologous pericardium for buttressing in cases of thin tissue. Ventricular injuries on the other hand, are best repaired with interrupted horizontal mattress stitches using pledgeted 3-0 polyprolene suture on an SH (or MH) needle. Control of a cardiac injury can initially be achieved with finger compression. In cases of larger injuries, a Foley catheter can be inserted into the cavity followed by inflation of the balloon and gentle traction. Care must be taken to not increase the size of the laceration when repairing the injury.
In most cardiac trauma cases, cardiopulmonary bypass is not needed. There are, however, rare instances when one needs to either perform coronary artery bypass grafting for a transected proximal left anterior descending (LAD) or right coronary artery (RCA) or repair avulsed pulmonary veins at their confluence into left atrium, which requires the heart-lung machine. Repair of other intracardiac injuries (valve tears, papillary muscle or chordal ruptures, ventricular septal defect (VSD)) should be weighed against the risks of full heparinization, as those can be frequently addressed once the patient is stabilized from other injuries. The majority of traumatic VSDs (mostly due to stab wounds) close spontaneously over time. The extent of other injuries needs to be considered when deciding to place the patient on cardiopulmonary bypass, particularly if head injuries are present as full heparinization is required.
Anterior right ventricle or left ventricle injuries close to the septum warrant a conscious pause to make the best effort in identifying the LAD course. If LAD is not transected, one should place a deep to the coronary artery horizontal mattress stitch (e.g., 4-0 prolene on SH needle) with the use of felt strips for a buttressing effect. Although an immediate hemostatic repair might be technically difficult on a beating heart, one should try to avoid narrowing or occluding the LAD, which might result in a large anterior infarct. Monitoring ECG changes after such a repair is important. If the LAD had to be sacrificed in such a repair, then a saphenous vein graft to the LAD should be performed in an expedient manner.
Chest tubes should be placed in the mediastinum and in the pleural space(s) if opened during the case. If at the end of the case the patient is hemodynamically stable, the chest should be closed with sternal wires.
Non operative blunt injuries
For patients, who do not exhibit severe cardiopulmonary compromise following blunt chest trauma, several studies should be obtained to evaluate for blunt cardiac injury. All patient with suspected cardiac trauma should have CXR, ECG, and if possible, cardiac troponins evaluated. Troponin adds specificity, while ECG has the best yield. If ECG is normal and the patient is hemodynamically stable, there is no need for an echocardiogram. Formal transthoracic echocardiogram should be done in the setting of hemodynamic instability or persistent ECG changes. Hemodynamically stable patients with abnormal ECG/troponin on presentation, should be admitted for at least 24 hours for monitoring. Figure 2 illustrates an algorithm widely used in the evaluation of suspected blunt cardiac trauma.
V. Postoperative Management
Post-operative management of patients with cardiac trauma involves initial hemodynamic stabilization with the use of pressors and inotropes. In addition to optimizing cardiac function, global perfusion needs to be assessed by monitoring end organ function. A complete secondary survey must be carried out to make sure no other injuries were missed. Damage to a major coronary artery either during the trauma itself or intraoperatively must be considered. If there is hemodynamic instability accompanied by EKG changes, emergent coronary angiogram may be warranted to assess the need for percutaneous coronary intervention. Special consideration should be given to potential intraseptal or valvular injury that was missed intraoperatively. If available, transesophageal echo should be performed.
VI. Summary (bullet points)
- If penetrating cardiac trauma is suspected, proceed to the OR
- If patient loses vital signs in the emergency department following penetrating chest trauma, proceed with emergent resuscitative thoracotomy
- Operative principles are the same regardless of mechanism of injury: relieve tamponade, stop the bleeding, and restore circulating volume.
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