Although the police department told you the scene was safe, you feel better hearing the assailant is in custody. Your patient, a 19-year-old male, has been stabbed multiple times in the chest. Bystanders told police he had been drinking heavily and began arguing with another party guest. No one saw exactly with happened, but they called 9-1-1 when they saw the patient lying on the floor bleeding.
The patient responds to noxious stimuli with moaning and eye opening. He has a rapid, weak radial pulse and is breathing about 20 times a minute. After applying a non-rebreather mask to the patient’s face, you begin to expose his chest. An EMT from the engine company asks if you want a backboard, and you tell him no, just the stretcher. A rapid assessment on the scene reveals two wounds to the patient’s anterior left chest at the third and fifth intercostal space. Breath sounds are clear in all fields. The initial physical exam reveals no other obvious injuries. Once in the back of the ambulance, you begin obtaining vascular access. You ask for a rider to assist you in the back and tell your partner to begin transporting emergently to the Level I trauma center downtown about 20 minutes away.
During transport, the patient becomes less responsive. His radial pulse becomes difficult to palpate, but he still has a palpable femoral and carotid pulse. You obtain and initial set of vital signs: pulse 110 and blood pressure 96/70. The patient’s breath sounds remain clear in all fields. You were able to easily place two large-bore IVs. The patient had great veins. A second set of vital signs reveal a pulse rate of 130 and blood pressure of 80/68.
IV fluid is run attempting to keep the patient’s blood pressure between 80 and 90 systolic. A blanket is placed on the patient to keep him warm. A more detailed physical exam doesn’t reveal much more information. You notify the hospital and then hand off the patient to the trauma team. After the call, your partner and third rider ask you what you think was going on.
This scenario gives us a traumatically injured patient going into shock. He has an altered level of consciousness that could have been caused by hypoperfusion to his brain, by the large amount of alcohol he had reportedly been consuming or some combination of both. His pulse is elevated, which is a common finding in patients presenting with shock. As the body’s blood pressure begins to drop, baroreceptors located in larger arteries sense the decrease in pressure and trigger the release of epinephrine. Epinephrine causes the heart rate to increase, which works to maintain blood pressure. Epinephrine also causes constriction of the blood vessels, again helping to maintain blood pressure. In this patient, the blood pressure continues to drop, suggesting the body is beyond its ability to compensate for shock—an ominous finding.
A couple of injuries can result in this patient’s presentation based on the mechanism of injury. The penetrating injuries to the chest could have lacerated large vessels of the heart, causing a loss of blood into the thoracic space that results in hemorrhagic shock. The lung could have been damaged, causing a tension pneumothorax, or a laceration into the pericardial sac could cause pericardial tamponade. Both these injuries cause obstructive shock.
It’s possible that the penetrating object went deep enough to damage the spinal cord, which could cause neurogenic shock—a form of distributive shock. So now our options are hemorrhagic shock, obstructive shock or distributive shock. Which one exists in this patient?
Both hemorrhagic and obstructive shocks present with elevated pulse rates. Neurogenic shock can present with slow or normal heart rates due to the disruption of autonomic ganglia.1 All three types of shock result in decreased systolic blood pressure. Hemorrhagic and obstructive shocks both present with a narrowed pulse pressure, which is the difference between the systolic and diastolic pressure, because of the arterial constriction. Distributive shock, including neurogenic shock, causes vasodilation, resulting in a drop in diastolic pressure and a widened pulse pressure.
In this patient, the pulse pressure and the tachycardia lead away from the consideration of neurogenic shock. Hemorrhagic shock and obstructive shock, either tension pneumothorax or pericardial tamponade, are still possible. A tension pneumothorax will present with diminished or absent breath sounds on one side. The patient in this case has clear, equal bilateral breath sounds. Pericardial tamponade can present with muffled heart sounds, which may be difficult for an unpracticed ear to recognize. The finding that presents with obstructive shocks not seen in hemorrhagic shock is venous distention. Typically jugular venous distension is discussed.
In this patient, it was noted the IV establishment was easy because the patient had good veins. This patient had a pericardial tamponade. Treatment in the prehospital setting is focused on stabilizing the patient as appropriate and transporting for definitive care. Patient airways must be managed to ensure adequate ventilation and oxygenation.
Vascular access is important, and volume should be administered to maintain a systolic pressure of 80 or 90 mmHg. Keep the patient warm. With isolated penetrating injuries, spinal immobilization isn’t indicated.2 Transport must be rapid to the closest most appropriate trauma center. Although treatment of patients with penetrating thoracic injuries presenting with shock isn’t dependent on identifying the exact cause of shock, physical findings can be relayed to the receiving facility to better streamline definitive care.
1. Marx J, Hockberger R, Walls R. Rosen’s Emergency Medicine Concepts and Clinical Practice, Sixth Edition. Mosby: Philadelphia, 436–437.
2. National Association of Emergency Medical Technicians. PHTLS, Seventh Edition. Elsevier: St. Louis, 2011, 256.