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Pericardiocentesis followed by thoracotomy and repair of penetrating cardiac injury caused by nail gun injury to the heart

Highlights • Nail gun injuries to the heart are potentially fatal and difficult to recognize.• Timely recognition and definitive repair of the injury is essential for patient survival.• Pericardiocentesis using a catheter capable of repeated and/or sustained aspiration/drainage can be a temporizing life-saving measure allowing for definitive repair in a controlled setting.• Pericardiocentesis must be considered as a bridge to definitive therapy in select cases of penetrating cardiac injury, particularly in rural settings with limited surgeon availability.


Introduction
The frequency of accidental injuries sustained as a result of pneumatic and explosive powered nail guns has been reported to be increasing [1]. The risk of injury is increased amongst novice users, as lack of training and experience have been shown to be independent risk factors [2]. The mechanism of injury can be secondary to ricochet effect or from inappropriate trigger pull. While most nail gun injuries are survivable, penetrating cardiac injuries from nail guns have been reported as infrequent occurrences associated with a high morbidity and mortality [3]. In most of the reported cases of cardiac nail gun injuries, survival of the patients is postulated to result from the actual nail wedging into the tissue providing locoregional tamponade. The described treatment of these injuries typically has involved median sternotomy or anterolateral thoracotomy, followed by repair of the cardiac injury [4]. However, cardiac tamponade resulting from penetrating cardiac injuries presents the added problem of associated hemodynamic instability. Cardiac tamponade is a life threatening emergency which requires decompression of the pericardium in addition to treatment of the underlying etiology. The choice between percutaneous and open drainage of the pericardium is based upon the etiology of tamponade and underlying pathophysiology. Periocardiocentesis is a well-known and accepted technique in providing relief of tamponade, but has traditionally been reserved for atraumatic etiologies [5]. Percicardiocentesis has also been described in the successful treatment of cardiac tamponade arising from blunt traumatic injuries [6]. The management of penetrating cardiac injuries has evolved to favor emergency department thoracotomy for the hemodynamically unstable or pulseless patient, and median sternotomy/anterolateral thoracotomy for the hemodynamically stable patient [7]. There are few studies that endorse the utility of pericardiocentesis in the setting of penetrating cardiac injuries.  tality rates when used as a bridge to definitive surgery [8]. Herein, we describe a unique case where penetrating cardiac injury with nail gun resulted in cardiac tamponade effectively treated with emergency room pericardiocentesis with a central venous catheter allowing for repeated aspiration, followed by operative anterolateral thoracotomy with repair of the cardiac injury.

Presentation of case
A 20 year old male was brought by his relative to our emergency department after having sustained a nail gun injury to his precordium at a construction site. On arrival, the patient was lethargic and noted to be tachycardic with a heart rate of 132 beats per minute and a blood pressure of 54/43 mm Hg. Primary survey revealed an intact airway with equal bilateral breath sounds, and faint peripheral pulses. Physical examination revealed a punctate wound in the anterior midline of his chest overlying his sternum with no foreign bodies, and prominent bilateral jugular venous distention. No other injuries were noted on secondary survey. Endotracheal intubation was performed and central venous access obtained (left subclavian and right femoral veins), after which our massive transfusion protocol was initiated. Arterial blood gas demonstrated a severe lactic acidosis (serum lactate 6.9). A chest X-ray was obtained which showed a foreign body overlying the cardiac silhouette (Fig. 1). A bedside ultrasound was performed, demonstrating a pericardial effusion (Fig. 2).
A decision was made immediately to take the patient to the operating room. Within the trauma bay, a pericardiocentesis was performed with aspiration of 100 cc of blood yielding a transient decrease in tachycardia and concomitant increase in blood pressure, as well as improved ventricular contractility on bedside echocardiogram. As a temporizing measure to provide further drainage, a central venous catheter was placed into the pericardium which drained an additional 100 cc of blood upon repeated aspiration (Fig. 3). Resuscitation with blood products was ongoing as the patient was taken emergently to the operating room. A left anterolateral thoracotomy was performed after which longitudinal pericardotomy provided immediate relief of tamponade. The nail was removed from the right atrium after which a brief period of cardiac arrest (5 s) was relieved by open cardiac massage. A 1 cm laceration of the right atrium was repaired with interrupted pledgeted #1 Ethibond suture. A 32 French chest tube was left in the left pleural cavity, and the chest was closed. In total, the patient received four units of packed red blood cells, four units of fresh frozen plasma and four liters of lactated ringers solution. Postoperatively, the patient was extubated and his chest tube was removed. He made an uneventful recovery and was discharged home.

Discussion
Although predominant involving the extremity, nail gun injuries pose a significant threat to construction workers and novice users with the potential of significant morbidity and mortality. Modification of nail gun design and improvement of training and safety measures at construction sites remain important public health measures to reduce the incidence of such injuries. The fatality of nail gun injuries to the heart is attributable to several factors including the difficulty in recognizing the injury itself, particularly in the absence of external foreign bodies [4]. Entry points into the skin can be barely visible and often do not reflect the severity of the underlying injury. Penetrating cardiac injuries have a high mortality rate amenable to reduction only by early recognition and early intervention. Therefore, a high index of suspicion is important. Tamponade physiology may or may not be readily apparent. When cardiac tamponade is present, early decompression followed by repair of the cardiac injury is essential in maximizing the chances for a favorable outcome. The rarity of these injuries precludes a failsafe algorithm for treatment. The cardiac component of the focused assessment using sonography for trauma (FAST) is a valuable imaging modality in the emergent setting to evaluate for cardiac motion and pericardial fluid, particularly in cases such as ours where the nature of the injury is unclear. In the case of the patient presented herein, both portable chest X-ray as well as cardiac ultrasound were useful in aiding in the diagnosis of cardiac injury and tamponade. While emergency room thoracotomy would have been justified given the patient's hemodynamic instability, prompt pericardiocentesis allowed for safe transfer of the patient to the operating room for thoracotomy and definitive repair under controlled and sterile conditions. The insertion of a central venous catheter into the pericardium allowed for sustained drainage and repeated aspiration of the pericardial sac precluding recurrent tamponade en route to the operating room. Pericardiocentesis is well described as an important step in the algorithm of managing medical causes of cardiac tamponade. Although it has been reported sporadically as having a role in the management of traumatic causes of tamponade, we believe that our case highlights a role for pericardiocentesis in the appropriate setting as a life-saving, temporizing measure until definitive repair of penetrating cardiac injuries. Particularly in rural and community hospital settings where a surgeon may not be immediately available, survival of the patient depends both upon prompt recognition of these seemingly occult injuries, as well as the timeliness of temporizing, albeit lifesaving measures such as paracentesis.

Conclusions
Nail gun injuries to the heart are rare but frequently fatal due to the difficulty in establishing a diagnosis and the severity of the injury itself. Their prevalence remains an issue amongst industrial site workers, and prompt recognition and immediate intervention are vital in preventing mortality. Our reported case highlights the subtlety of presentation amongst nail gun injuries to the heart and should increase the reader's awareness of such injuries and the difficulties that can exist in arriving at a prompt diagnosis. Cardiac tamponade in the setting of trauma must be considered in the differential diagnosis of the hemodynamically unstable patient with penetrating injuries. Moreover, while emergency department thoracotomy remains the gold standard in the treatment of penetrating cardiac injury in the unstable patient, pericardiocentesis (particularly with a catheter which can be used for sustained and/or repeated drainage) can be a potentially life-saving adjunct to definitive repair of the injury and must be considered to be part of the treatment algorithm particularly in rural and community hospital settings where surgeon availability is variable.

Conflicts of interest
There are no conflicts of interest.

Sources of funding
No sponsors or funding sources were involved in the preparation of this manuscript.

Ethical approval
This case report is not a research study.

Consent
Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the editor-in-chief of this journal on request.

Authors contribution
Dr. Zoha was the treating physician for the patient. Drs. Prabhakaran, Chirumamilla, and Petrone contributed to the manuscript writing. Drs. Marini and Savino contributed to revisions of the manuscript.

Guarantor
Drs. Zoha and Prabhakaran are the guarantors.