Nail Gunshot Induced Hemopericardium, Detected by Point-of-care Ultrasound (POCUS) in the Emergency Department

Abstract

Penetrating injuries to the heart often lead to pericardial effusion (PCE) that may result in cardiac tamponade which can be rapidly fatal. Thus, early detection of PCE is extremely important in initial resuscitation. A 37-year-old man without any past medical illness was sent to our emergency department by ambulance due to left chest wall penetrating injury by nail gun 30 minutes ago. Upon presentation, the patient was agitated and diaphoretic. The penetration site was in the region of cardiac box, which raised awareness that possible heart injury has been inflicted. Point-of-care ultrasound (POCUS) was used immediately to screen for PCE which was present. In addition, POCUS revealed a hyper-echoic point in the left ventricle (LV) which we speculate is the foreign body (FB). Non-contrast computed tomography confirmed the presence of PCE and FB in the LV. The patient received emergent blood transfusion and was immediately transferred to a level-1 trauma center where removal of FB and cardiorrhaphy of LV apex was performed. He was discharged one week later under stable condition. Take home Message: The presence of hemopericardium in penetrating thoracic trauma may cause life threatening injuries such as cardiac tamponade which warrants immediate intervention. POCUS is a reliable, repeatable, and readily available tool at bedside for detecting PCE in penetrating thoracic trauma patients. Given its high sensitivity and specificity, POCUS should be used as the initial screening tool for the presence of PCE in all thoracic penetrating trauma patients.

Introduction

Penetrating cardiac injuries are rare, and only account for 0.1% of all trauma admissions. 1 Although uncommon, penetrating cardiac injury is a true medical emergency that presents with a high prehospital and in-hospital morality rate. Any penetrating trauma to the thorax or upper abdomen should raise awareness of a cardiac injury. Rapid confirmation of cardiac injuries and prompt intervention is of paramount importance to patient’s survival. Utilization of point-of-care ultrasound (POCUS) in primary survey is an effective and reliable method for evaluating cardiac injuries and hemopericardium in trauma patients. We report a rare case of left ventricle (LV) penetrating injury with hemopericardium, detected initially by POCUS that led to prompt intervention and ultimately patient’s survival.

Case Report

A 37-year-old man without any past medical illness was sent to our emergency department by ambulance due to left chest wall penetrating injury by nail gun 30 minutes ago. The patient did not provide a clear history of how the incident happened but stated that after the incident he briefly lost consciousness and vomited 2 times after waking up. Upon arrival, the patient was diaphoretic and agitated with initial blood pressure of 93/67 mmHg, heart rate of 106 beats/min, respiratory rate of 20 breaths/min and temperature of 36.9°C. Physical examination revealed a small penetrating wound without visible foreign body (FB) at left costal margin area below and medial to the left nipple. Chest X-ray disclosed a FB within the thoracic cavity at the inferior border of the cardiac region ( Fig. 1 , arrow). A POCUS was performed and revealed pericardial effusion (PCE) of 5.6 mm in thickness ( Fig. 2 , arrow) and a hyper-echoic lesion in the LV which we presume is the FB ( Fig. 2 , arrow head). A non-contrast computed tomography confirmed a FB ( Fig. 3 , arrow) piercing into the LV with surrounding PCE. The patient received emergent blood transfusion and was transferred to a level-1 trauma center immediately. Approximately 49 minutes after arrival at the trauma center, the patient received cardiorrhaphy of LV apex and FB removal. He was discharged one week later under stable condition.

Fig. 1 . Chest X-ray showing a 4.5 cm long foreign body at the inferior border of the heart within the thoracic cavity (arrow).

Fig. 2 . Point-of-care ultrasound showing a hyper-echoic lesion, presumbly the foreign body, in the left ventricle (arrow head) and 5.6 mm thickness of pericardial effusion (arrow).

Fig. 3 . Non-contrast computed tomography showing a foreign body (arrow) piercing the left ventricle with surrouding pericardial effusion.

Discussion

Thoracic trauma is a common form of trauma, and is reported in > 10% of all trauma admissions. 2 Any injury in the “cardiac box”, an area outlined superiorly by the clavicles and sternal notch, laterally by the nipple line, and inferiorly by the costal margins should raise suspicion for cardiac injuries. 3 Most penetrating cardiac trauma is related to stab wounds or gunshot wounds and presents with a prehospital mortality rate as high as 94% and an in-hospital morality rate of 50% among initial survivors. 4 Deaths from penetrating cardiac trauma are result of hemorrhagic shock (77.5%) and cardiac tamponade (22.5%). 5 In penetrating trauma, since right ventricle (RV) forms most of the anterior surface of the heart, it is entered more often than the LV (62% for the RV vs. 38% for the LV). 6 However, the prognosis for LV penetrating trauma is much worse, as less than 2% of LV injury reached the hospital alive. 6

Cardiac penetrating injuries can lead to PCE and as little as 50 mL of pericardial blood can cause cardiac tamponade that can be rapidly fatal. 7 Therefore, timely diagnosis and intervention for hemopericardium is important for patient’s survival. Extended focused assessment with sonography for trauma (E-FAST) is a noninvasive and repeatable diagnostic tool that has been incorporated in primary survey of trauma patients across the globe. Many reports have demonstrated that E-FAST is effective in diagnosing PCE in trauma cases. One pooled-study showed that E-FAST has an excellent sensitivity of 91% and specificity of 94% in detecting PCE in trauma patients. 8 Another study with a sample size of 2,100 penetrating trauma patients have demonstrated that POCUS can achieve an outstanding sensitivity of 95% and specificity of 100% in detecting PCE. 9

In addition, in torso stab wounds in which dual-cavity (chest and abdominal cavity) injuries can potentially happen, correct sequence of which cavity to explore first is important. Life threating injuries in the chest such as tension pneumothorax, massive hemothorax and cardiac tamponade should be addressed first before managing any abdominal injuries. 10 In these cases, POCUS again play a crucial role to confirm or exclude the presence of PCE and reduce the chance of inappropriate surgical sequence. 10 Finally, physicians should be aware that the concomitant presence of left hemothorax may lead to false negative pericardial ultrasound and further diagnostic tests should be performed in these cases. 11

This case illustrates the importance of utilizing POCUS as an adjunctive study in the primary survey of all thoracic trauma patients, especially those with shock or cardiac tamponade signs. Sub-xiphoid view is usually the initial point for PCE screening, however, due to variation in body size and mass, long and short axis cardiac view can also be performed to ensure the most accurate result. In hemodynamically unstable thoracic trauma patients, POCUS should be prioritized over other imaging modalities since it can be performed readily and swiftly at bedside without the patient having to be transferred outside of trauma blue area.