"Someone's been shot": An EMS case study
There are critical decisions made in the prehospital emergency care of unstable patients with penetrating trauma
The crew heard a "Pop, pop, pop" nearby, and knew it wasn't just a car backfiring. The dispatch was for "someone shot," and they were two blocks away. Law enforcement worked quickly to secure the area, and asked that EMS approach quickly. A young man was on the ground, unconscious. He was warm. There was no blood. A rapid assessment found multiple wounds in his chest, and he would respond to painful stimuli. He had a weak pulse, and agonal respirations.
The trauma protocol called for a rapid removal, and the police were nervous because a high powered automatic weapon was used and the perpetrator might still be in the area.
The patient was strapped on a backboard and moved to the ambulance, where the paramedic could do a full secondary assessment. The injured man had no head wounds, but there was blood in the mouth and coming up from the airway. The neck veins were distended. The victim was breathing in a very shallow fashion, and the paramedic noted that the right side of the chest "felt like a full balloon."
He carefully removed the muscular man's shirt, making sure he did not cut through the bullet holes. There was no air moving into that side of the chest on auscultation. He had two wounds on that side of his chest: there was an additional open wound to his left anterior chest, which caused a 4x4cm open area to be blown away. This was covered initially with a large trauma dressing. There was an additional wound to his upper left thigh. He had no other wounds to the extremities or his back, and he withdrew all four extremities from painful stimuli. The paramedic was able to barely palpate a carotid artery pulse, so he moved immediately to primary interventions.
As the ambulance began to move on a 20-minute transport to the trauma center, the crew communicated a "trauma alert," critical in the case of an unstable penetrating trauma patient. The paramedic arranged equipment for a quick set of life-saving interventions.
The trauma protocol called for the paramedic to "restore perfusion," which is an important concept. In penetrating trauma, this means performing techniques that will allow the most important organs to have adequate blood supply, but not accelerating hemorrhage or fulfilling any specific numbers for blood pressure or pulse or oxygen saturation.
To do this, the paramedic would need to:
- Control the airway and ventilate using a bag-valve-mask
- Apply a seal to the chest wound, and decompress any tension pneumothorax
- Infuse enough fluid to restore critical perfusion
- To infuse fluids in a patient with open chest wounds, the paramedic would try to get intravenous access above and below the diaphragm. This is usually done below the diaphragm using an intraosseous infusion device.
- Use pressure infusers to give rapid fluid boluses
The important first interventions are to ventilate and secure an airway. The EMT inserted an oral airway and started bagging the patient with high flow oxygen. It was very difficult to ventilate, so the paramedic knew he would have to seal the chest wound quickly and decompress the chest. He needed an occlusive dressing to the left chest wound that would seal it, and that would adhere to the skin despite the blood, sweat, and hair on the man's chest. A new generation of occlusive dressings is available for that purpose, and one version of the dressing is available with a pressure relief valve system that would allow air to escape from the open wound, but would not allow it to get sucked back into the chest. These dressings have been used in recent war zones, and have been designed to be quickly applied and transparent, so that the trauma team can visualize the wounds once the patient arrives at the hospital.
The SAM Chest Seal is the self-adherent occlusive dressing that the paramedic applied to the open left chest wound. The hydrogel adhesive was strong and flexible, so it adhered to the skin in the presence of blood, hair, and diaphoresis. With the cap removed, the dressing functions as a valve chest seal with one-way outward flow. Once in place, the paramedic performed a needle decompression of the right chest, due to the EMT's ongoing difficulty trying to ventilate the patient, the lack of air flow and chest wall movement on that side, and the feeling that the chest "was like a tight balloon." The man had a muscular chest wall, so the paramedic inserted one of the three inch long needle and catheter devices into the second intercostal space, and had to almost bury the needle to the hub before he could get into the pleural space. He heard a large rush of air, followed by a "thank you" from the EMT that is was now much easier to bag the patient.
The patient had a large antecubital vein in the right arm, so a large catheter was inserted and a normal saline infusion started with the bag put in a pressure infusion cuff. The paramedic then inserted an intraosseous needle into the patient's right tibia, away from the injured left leg. He started another infusion of normal saline with a pressure infusion cuff.
The patient continued to have blood coming up from his mouth, so the paramedic quickly performed an endotracheal intubation. The blood was coming from the patient's lungs, so the paramedic relayed that information to the trauma center, and the crew suctioned the airway on a regular basis to keep the blood from occluding the tube and compromising ventilation.
After about 2 liters of fluid, the patient developed a regular pulse on the pulse oximeter, with a saturation of about 94%. His diaphoresis disappeared, and the wound on his left thigh began to bleed more profusely. The paramedic considered applying a tourniquet, but instead started with direct pressure, and the bleeding was controlled. The victim started to stir around a little.
With these signs of improving perfusion, he takes the pressure infusers off the bags, and cuts the fluid administration rate back to about 100cc per hour. As they arrive in the trauma center Emergency Department, the victim has a pulse rate of 110, an oxygen saturation of 96%, and is moving all four extremities. The trauma team assumes care of the patient, with a plan for rapid transport to the operating room.
After weeks of treatment, and multiple operations the patient was able to leave the hospital.
Decision making in cases of critical penetrating trauma
There are critical decisions made in the prehospital emergency care of unstable patients with penetrating trauma. The key assessments and interventions are summarized as:
Integrity of the body and important body portions: Penetrating wounds to the face, neck and chest create immediate and profound airway problems. Where possible, the patient should be positioned to control his or her own airway. Spine immobilization should be dictated by mechanism of injury and evidence of trauma to the spine. Many patients with penetrating wounds away from the spinal column can be managed without immobilizing the spine, and that may simplify airway management. Chest and neck integrity is necessary for preventing major bleeding, and allowing the patient to both ventilate and perfuse. Loss of integrity, particularly with major bleeding, can be addressed by direct pressure, the new adherent dressings, or another occlusive dressing.
Airway: Where needed, airways using oral, nasal, or cricothyroid routes are lifesaving. With some facial injuries, before bleeding and swelling progress, the EMT can perform an oral or digital intubation to secure the airway. In some cases, the patient will need a needle or surgical cricothyrotomy, which can be performed by paramedics in some systems. Crews that are managing critical airways across long prehospital care timelines must be prepared with a number of options for airway management.
Ventilation: The chest wall must be intact for the patient to breathe, and the pleural space cannot be filled with air or blood. Filling those spaces with air creates a life threat to the patient, and the air must be removed with a needle or a chest tube. A tension pneumothorax also creates filling problems for the heart, and perfusion will decrease.
Oxygenation: Lung integrity is important for oxygenation. Supplemental oxygen is usually helpful.
Perfusion is the ability of the body to provide critical oxygenation to cells and remove waste products, and the compromise of perfusion is called "shock". Enhancing both volume and oxygen delivery to the patient is needed to restore or maintain perfusion in the traumatized patient.
Surgical intervention: EMS providers should be experienced in their work with local hospitals or the trauma center, and capable of "making the call" in a timely manner that a crisis is en route and will need to be managed at the ED.