Multiple Penetrating Injuries to the Heart Diagnosed With Ultrasonography.

ABSTRACT: Penetrating heart injury poses significant diagnostic and therapeutic challenges. Patients may initially appear in extremis or in stable condition. Surgeon-performed ultrasonography is effective in determining the presence or absence of tamponade. Definitive repair requires cardiorrhaphy, using a median sternotomy or thoracotomy incision, depending on the suspected injury site(s). Frequent postoperative complications can usually be managed without reoperation. Echocardiography, electrocardiography, and cardiac catheterization may be used postoperatively in reassessment. A patient with stab wounds to both ventricles of the heart is described.

PENETING INJURY to the heart can include stab wounds or missile wounds of high or low velocity. Cardiac injury is suspected when any wound is present at or near the precordial region or when the missile transit is suspected to have included the mediastinum. Ultrasonography in the trauma room has proven to be effective in diagnosing pericardial fluid, leading to more rapid definitive treatment and resulting in higher curvivability rates. We describe a patient with two separate stab wounds to the chest who was diagnosed by ultrasound to have pericardial fluid.

CASE REPORT

A 37-year-old man had multiple torso stab wounds, including a superficial, 10 cm diagonal wound to the left side of the neck, a 1 cm wound just inferior to the left nipple, two punctate-type wounds less than 1 cm adjacent to the sternum on the left, and a 2 cm wound in the left upper quadrant of the abdomen. Before the patient's arrival, a chest tube had been inserted on the left, with an initial output of 2000 mL of blood. He was transported by helicopter to the Trauma Resuscitation Unit, where initial vital signs included a systolic blood pressure of 84 mm Hg, pulse rate of 120/min, respiratory rate of 24/min, and a Glasgow Coma Scale score of 13.

The patient was intubated and became progressively unresponsive, and rapid volume infusion was continued. A size 12F trauma catheter was placed in the right femoral vein. Ultrasonography showed blood in the pericardium, and a chest radiograph revealed increased density of the left lung, suggesting contusion and hemorrhage but no pneumothorax. Initial hematocrit value was 32%. Within 9 minutes of arrival, the patient was taken to the operating room for a median sternotomy. The pericardium was opened, revealing approximately 200 mL of blood and fresh clot. Two separate cardiac injuries were found, each from separate stab wounds. One was a 1.5 cm wound to the right anterior ventricular wall, the other a 1 cm left ventricular wound at the apex. Both of these injuries were actively bleeding, and repair was made with a double-pledgeted polypropylene mattress suture. The stab wound to the neck appeared superficial; the abdominal wound was locally explored and did not penetrate the peritoneum.

The postoperative course was uneventful, with extubation on postoperative day 2. Cardiac rhythm remained stable, and no murmurs were detected. Echocardiogram on postoperative day 4 revealed normal left ventricular function with minimal anteroseptal dysfunction and conduction abnormality. The patient was discharged home on postoperative day 5, doing well.

DISCUSSION

Cardiac injury from penetrating wounds of the precordium poses significant challenges. Most injuries lead to death, but an estimated 20% of patients with cardiac wounds arrive at hospitals with some signs of life. [1] Cardiac injuries that lead to immediate death do so from exsangnination, cardiac tamponade, coronary artery laceration, valvular disruption, or interruption of essential conduction pathways. Survival approaches 70% for those who arrive with recordable vital signs. [1] This salvage rate requires rapid diagnosis and transport to the operating room for repair of the cardiac injury.

Recent data confirm that ultrasonography is useful in establishing the diagnosis of hemopericardium. Current protocols as advocated by Rozycki et al [2] recommend an operation if the result is positive, a pericardial window or echocardiogram if the result is equivocal, and observation and discharge if the result is negative. They support a sensitivity of 100% and a specificity of nearly 97%. Benefits of ultrasonography include its lack of invasiveness, repeatability, and rapidity. In that series, total mean time from diagnosis to the operating room was about 12 minutes.

Pericardiocentesis does not provide definitive treatment of cardiac penetration with tamponade but may be used as an adjunct in initial stabilization of patients awaiting transport to tertiary care facilities. An indwelling catheter in the pericardial sac may provide a means to remove accumulating blood and allow hemodynamic stability before thoracotomy. The subxyphoid pericardial window should be used to confirm the diagnosis of pericardial tamponade in stable patients if results of ultrasonography or echocardiography are equivocal. For patients in unstable condition, an urgent thoracotomy or median sternotomy is the recommended procedure of choice. [3,4] These diagnostic modalities are useful because the classic physical signs of pericardial tamponade--hypotension, muffled heart sounds, and distended neck veins--are often lacking in the trauma situation. [5]

Tamponade occurs as a result of the body's own compensatory mechanisms. The defect in the pericardium becomes sealed off by fat or clot. This leads to accumulation of blood in the pericardial sac that causes a reflex response of tachycardia. Increased circulating catecholamines lead to an increase in ventricular filling pressure and enhanced myocardial contractility. This, in turn, leads to augmentation of right ventricular diastolic filling, which produces pulsus paradoxus (exaggerated decrease in systolic blood pressure during inspiration). Cardiac output is initially maintained if the preload is improved with volume infusion. This produces compensated tamponade. However, when the limits of distensibility are reached, even small amounts of additional pericardial blood will cause a significant decrease in cardiac output. This decrease in cardiac output is also due to septal shift causing profound systemic hypotension, which can occur suddenly and unexpectedly in the patient. [3]

Cardiac injuries are repaired through a thoracotomy or median sternotomy incision. A thoracotomy incision is preferred if a posterior wall injury is suspected. The incision is made in the fifth intercostal space as a left anterior or anterolateral thoracotomy The pericardium is opened anterior and parallel to the phrenic nerve. A sternotomy incision is versatile in allowing extension into the neck or abdomen. It allows superb exposure to anterior heart injuries. [3]

Cardiorrhaphy is done using pledgeted mattress sutures. Strips of pericardium can be used as pledgets if the synthetic variety is unavailable. Digital pressure is maintained over the injury to allow ease of repair. Heart lacerations in proximity to coronary vessels are repaired using a horizontal mattress suture placed deep to the vessel to avoid vascular occlusion. For large wounds, balloon occlusion of the heart injury can be used by inserting a Foley catheter and applying gentle traction to provide temporary hemostasis. Injuries to coronary vessels may be repaired primarily with or without bypass. Adjacent small coronary vessels that are injured may be ligated. [3]

Postoperative complications are common and include immediate coagulopathy, sepsis, shock, arrhythmias, myocardial infarction, and encephalopathy. Delayed complications include ventricular septal defects, conduction problems, wound infection, or costochondritis. The most common delayed complication is a ventricular septal defect. Because interventricular septal injuries are often not diagnosed at the time of injury, follow-up should include 2-dimensional echocardiography, electrocardiography, and cardiac catheterization in symptomatic patients. [6]

Our patient had multiple stab wounds to the anterior aspect of the chest and a cardiac injury leading to tamponade, which was rapidly diagnosed by surgeon-performed ultrasonography. This led to quick transportation to the operating room. Because the patient was believed to have an anterior heart injury, a median sternotomy was done. Exploration showed that two separate stab wounds caused a multichambered injury. Although a multichamber injury is associated with significantly higher mortality than single-chamber injuries, our patient was discharged without sequelae and remains well.

References

(1.) Naughton MJ, Brissie RM, Bessey PQ: Demography of penetrating cardiac trauma. Ann Surg 1989; 209:676-683

(2.) Rozycki GS, Feliciano DV, Ochsner G, et al: The role of ultrasound in patients with possible penetrating cardiac wounds: a prospective multicenter study. J Trauma 1999; 46:543-552

(3.) Ivatury RR: Injury to the heart. Trauma, Feliciano DV, Moore EE, Mattox KL (eds). Stamford, Appleton and Lange, 3rd Ed, 1996, pp 409-417

(4.) Laws HL: The broken heart. Am Surg 1998; 64:485-492

(5.) Demetriades D, VanderVeen PW: Penetrating injuries of the heart: experience over two years in South Africa. J Trauma 1983; 23:1034

(6.) Mittal V, McAleese P, Young 5: Penetrating cardiac injuries. Am Surg 1999; 65:444-448