Chapter 11 Operative Exposure in Thoracic Trauma: Exposure of Injuries to the Heart

This chapter will discuss exposure of actual or suspected injuries to the heart. Though the major emphasis is operative exposure, management of specific injuries to the heart will also be briefly covered.

Learning Objectives

By the end of the ASSET course, participants should be able to do the following:

1. Describe the signs and symptoms of pericardial tamponade.
2. Describe the clinical indications for median sternotomy, left anterolateral thoracotomy (resuscitative thoracotomy), and “clamshell” bilateral thoracotomy.
3. Demonstrate the surgical technique of pericardial window.
4. Describe the techniques for controlling hemorrhage from atrial and ventricular cardiac injuries.
5. Describe the surgical technique to repair ventricular wounds that are in juxtaposition to the coronary arteries.
6. Describe techniques to expose the posterior heart for evaluation.

Considerations

• Every penetrating injury to the chest—especially to the precordium, or “cardiac box” (Figure 1)— should raise suspicion of a cardiac injury until proven otherwise, especially if associated with hypotension.
• The combination of hypotension, distended neck veins, and distant cardiac sounds (Beck’s triad) is variably present in patients with cardiac tamponade.
• Unexplained tachycardia and hypotension are the most common clinical findings. In rare occasions with small cardiac wounds and short prehospital times, the patients may not be hypotensive on admission.
• Patients with tamponade are often very anxious and do not want to lie down. They may become combative if forced to do so and may arrest due to loss of sympathetic tone.
• In patients with tamponade and severe blood loss, the neck veins may not be distended.
• Cardiac sounds are usually distant in cases of cardiac injury, but this finding is often missed in a noisy trauma bay.
• Consideration should be given to whether cardiopulmonary bypass and assistance from a cardiac surgeon might be required.

Investigations

• Focused assessment with sonography in trauma (FAST) in the emergency room is the most reliable investigation.
• A positive FAST in the presence of hypotension is an absolute indication for immediate operation (Figure 2).
• There is no role for pericardiocentesis in the treatment of cardiac tamponade.

Incisions

• The choice of incision in cases of suspected cardiac injury will be dictated by the stability of the patient, the suspected location of the injury, the setting, the equipment available, and the surgeon’s experience.
• The median sternotomy (chapter 10) provides excellent exposure for isolated injuries to the anterior heart and great vessels but requires more equipment and time to perform than an anterolateral thoracotomy (resuscitative thoracotomy, or RT).
• RT is the incision of choice for patients who present in extremis (chapter 10). It provides rapid access to the chest with a minimum of equipment.
• The RT is best suited for rapid relief of cardiac tamponade and will allow for exposure of the inferior and posterior portions of the heart and portions of the left chest, as well as crossclamping of the descending thoracic aorta.
• The “clamshell” bilateral thoracotomy is used as an extension to the RT when additional exposure of the heart is needed or if there are concomitant injuries in the right chest.

The Pericardial Window

The subxiphoid transdiaphragmatic pericardial window is an excellent diagnostic adjunct to rule out cardiac injury in hemodynamically stable patients with suspected cardiac injury when the FAST exam is not available or is nonconfirmatory.

• Hemodynamically unstable patients with suspected cardiac tamponade should not have a pericardial window performed but should undergo urgent median sternotomy or RT.
• The pericardial window is often performed during an exploratory laparotomy to rule out pericardial fluid.

Technique

• An incision is made on the midline over the xiphoid process and is extended several centimeters down onto the abdominal wall. A plane is developed between the underside of the xiphoid and the peritoneum just inferior to the central tendon of the diaphragm.
• The central tendon of the diaphragm (directly over the heart) is grasped with two Allis clamps, and a small (1 cm) window is made into the pericardium with scissors (Figure 3).
• If the pericardial window reveals blood, the chest is opened (usually median sternotomy) to allow inspection of the heart and cardiac repair.
• If the procedure does not reveal any blood, the pericardium should be irrigated with warm saline to look for clot. The window can be closed, or it may be drained to monitor for bleeding from the pericardium.

Pericardial Window Pitfalls

• If care is not taken to minimize bleeding during the dissection, or if the peritoneum has been opened in a patient with hemoperitoneum, the pericardial window may be falsely positive from blood external to the pericardial sac.

Atrial Injuries

• Atrial wounds can be occluded by digital pressure, approximation of the edges with a vascular clamp (Figure 4), or forceps (DeBakey or Russian).
• A simple running suture with 2-0 or 3-0 polypropylene (with or without pledgets) is generally sufficient to repair the heart (Figure 5). Care should be taken, as the walls of the atria are thin and can easily tear. The lumen of the atria can be significantly reduced without consequence as long as the inflow and outflow are not compromised.
• Alternatively, a surgical stapler can be used to repair an atrial injury.
• The right atrium is more anterior and therefore more commonly injured by stab wounds. The right atrium is well visualized through a left lateral anterior thoracotomy or a sternotomy.
• The left atrium is more difficult to repair, due to its posterior position.
• Patients with atrial injuries should be placed in the Trendelenburg position to decrease the possibility of air embolism.

Ventricular Injuries

General Considerations

• The major mistake made by surgeons who do not frequently operate on the heart is to perform interventions too quickly. As long as the heart is beating, the approach to a ventricular injury should be methodical and measured.
• If the heart is not beating, restoration of cardiac function should be a priority, with open heart massage (between the palms), ongoing resuscitation, cardiac drugs, and cardioversion, as indicated.
  • If appropriate suture and expertise are available, rapid repair of the wound prior to restoration of cardiac function may be considered.
  • It is tempting to repair injuries prior to restarting the heart, but this may take longer than anticipated, and the longer the heart is not beating, the more likely the patient is to die from the injury.

• If the heart has been restarted, it is likely to be irritable, and immediate attempts to suture may exacerbate this irritability. It is advisable to allow a couple of minutes for the heart to recover and for anesthesia to catch up before sticking it with a needle.
• Maintain open communication with the anesthesia team, and discourage them from giving vasopressors or excessive resuscitative products.
• The right ventricle is a thin-walled and lowpressure chamber, and as such the vast majority of wounds there can be initially controlled with gentle fingertip occlusion alone (Figure 6).
• The walls of the left ventricle are thick, and in the case of stab wounds, they are often not actively bleeding and can be easily controlled with digital pressure.
• The use of a Foley balloon placed into the ventricle to obtain temporary control of bleeding is well described. This is almost never needed, however, and its use has the risk of making the injury bigger if care is not taken to avoid pulling up on the catheter too aggressively.
• Skin staples have also been described as a quick way to temporarily control bleeding from ventricular injuries, but these tend to cause more injury to the cardiac muscle and are unlikely to be superior to simple fingertip occlusion. Additionally, skin staples are more likely to pull through the epicardium during cardiac massage or if the heart becomes distended.
• The use of pledgets is controversial but useful to prevent tearing of the suture through the cardiac muscle, especially for surgeons who infrequently operate on the heart.
• Teflon pledgets are generally used, but if not available, one can use the patient’s pericardium to fashion pledgets. When using the patient’s pericardium, the key is to pass the suture though the edge of the pericardium prior to cutting out the pericardial pledget. The sequence is to pass the double-armed suture through the pericardium on one side, then across the cardiac injury, and then through the pericardium on the opposite side prior to cutting out the pieces of pericardium.
• Ventricular injuries are repaired with monofilament sutures, such as 2-0 or 3-0 polypropolene (usually with pledgets), with either a mattress or running suture, dependent on the injury (Figure 7).
• Sewing on a full left ventricle can make the wound bigger.
• Injuries to the posterior left ventricle are technically challenging, because they require lifting of the heart to expose and repair. Lifting the heart can cause arrhythmias and even arrest by cutting off venous return.

• Several techniques are described for obtaining access to the posterior wall of the heart, including the following:
  • Slowly lifting the heart
  • Sequentially placing gauze pads behind the heart
  • Placing a clamp or suture on the posterior pericardium and retracting it caudally
• If an injury to the posterior wall of the heart can be controlled with digital pressure and extreme cardiac instability results from attempts to lift the heart, the use of cardiopulmonary bypass may be indicated.
  • Extension of a sternotomy laterally to a left thoracotomy may aid in exposure of the posterior heart.
  • If bypass is not available, temporary inflow occlusion of the inferior and superior vena cavae (Figures 8 and 9) will empty the heart and enable expeditious repair of the nowempty left ventricle.
  • Keep in mind that once inflow occlusion is accomplished, the heart will stop, so it is important to have sutures ready. Quickly throw one suture, and then allow the heart to recover; repeat as needed to effectively repair the wound.

Juxtacoronary Injuries

• The repair of ventricular wounds adjacent to coronary arteries is performed by placing “U” sutures or horizontal mattress sutures such that the suture does not occlude the coronary arteries (Figures 10 and 11).
• The function of the myocardium distal to the repair, as well as the intraoperative electrocardiogram, should be monitored to identify (and prevent) coronary artery occlusion and ischemia.
• Partial transection of a major coronary artery in the distal third of the coronary artery can be treated by ligation.
• If the coronary artery injury is proximal or on a major branch, ligation may be fatal. Optimal repair is best achieved with the help of a cardiothoracic surgeon.

Blunt Myocardial Rupture

• Cardiac rupture due to blunt trauma is almost always fatal, except for atrial rupture, which is relatively rare.
• This injury should be suspected in a blunt trauma patient with a positive pericardial ultrasound.
• Intracardiac valvular injuries or papillary injuries should be repaired at a later time, under controlled settings, with the aid of the cardiothoracic team.