This patient sustained a penetrating traumatic injury to the left chest and presented to the emergency department with hemodynamic instability (tachycardic and hypotensive). Some differential diagnoses to consider on arrival include tension pneumothorax, cardiac tamponade, aortic injury, or aero-digestive tract injury. Prior to taking a detailed history on any trauma patient, a primary survey should be performed. The goal of the primary survey in a trauma patient is to identify and treat any life-threatening injuries as soon as possible. The primary survey is also known as the “ABCs.” Sometimes it is referred to as the “ABCDEFs.” This acronym stands for Airway, Breathing, Circulation, Disability, Exposure, and FAST exam (How to learn eFAST exam for free). Each letter is addressed and assessed in the order they exist in the alphabet. This creates a methodical, algorithmic approach to assist the practitioner in assessing the trauma patient for life-threatening injuries. The sonographic view shown in this question is the subxiphoid (cardiac) view and demonstrates the presence of free fluid. Free fluid on ultrasound appears black, or “anechoic” and is assumed to be blood in the setting of trauma. The free fluid is highlighted by red stars in the image below. The collapse of the right ventricle is shown by the yellow arrow in the below image.
In conjunction with hemodynamic instability and a history of penetrating chest trauma, this sonographic view strongly supports the diagnosis of cardiac tamponade. Consulting the general surgery team for exploratory laparotomy (Choice A) would be the correct course of action for a patient with hemodynamic instability and free fluid on the other abdominal views of the FAST exam. Needle decompression of the chest (Choice B) would be the correct initial treatment for a tension pneumothorax. The patient described in the case has clear bilateral lung sounds, no tracheal deviation mentioned, normal O2 saturation on room air, and sonographic demonstration of cardiac tamponade. A CT scan of the chest, abdomen, and pelvis (Choice D) would be indicated in this patient if he had normal vital signs and no free fluid on the FAST exam. A pericardiocentesis (Choice C) is the most appropriate next step in the management of this patient with cardiac tamponade to relieve signs of obstructive shock. It should be noted that this procedure has limitations and is not always effective. Pericardiocentesis is a temporizing treatment with pericardiotomy being the definitive therapy. Blood in an acute hemopericardium may clot and be unable to be aspirated with a large-bore needle. The procedure may injure surrounding organs, such as the liver, intestines, or heart itself. Ultrasound-guidance should be used whenever possible to avoid injury to surrounding organs. Emergent thoracotomy to relieve the cardiac tamponade should be performed on any patient with confirmed cardiac tamponade and cardiac arrest in the Emergency Department. Correct Answer: C