Spinal Cord Injury

     First responders are dispatched to the scene of a motorcycle accident. Upon arrival, they find a victim lying supine on the street. The victim informs them that he's fine and wants to go home. However, due to the potential mechanism of the man's injury and the significant damage to his nearby motorcycle, the first responders hold gentle inline manual cervical immobilization while proceeding with their interview.

     They convince the patient to allow them to conduct a rapid assessment. As part of this process, they conduct a rapid neurological exam, and find the patient has no sensation or movement in his lower extremities. Determining that this is a load-and-go situation, they explain to the patient that he needs to be evaluated at the emergency department. The patient agrees.

     The providers carefully immobilize the patient with a cervical collar and long spine board, noting no trauma to his back upon log-roll. They apply oxygen via nonrebreather at 15 lpm, initiate intravenous access (16-gauge, normal saline), and apply the ECG monitor (sinus rhythm) and pulse oximetry (98%). Initial vital signs are BP 82/40, HR 72 and RR 20. They complete a detailed assessment during transport.

     Throughout transport, the patient has no complaints of pain. He still has no sensation or movement in his lower extremities, though both are good in the upper ones. He's had no chest wall impairment and can breathe on his own. He is, however, exhibiting a difference in skin temperature: cool and diaphoretic from the nipple line up, but warm and dry below. The man also has minor abrasions throughout all of his extremities. The crew initiates IV solutions and monitors the blood pressure continuously.

     The providers identify that the patient is experiencing neurogenic shock, which can result from severe damage to the central nervous system (brain and spinal cord), and opt to administer an infusion of dopamine, a medication used to constrict blood vessels for blood pressure support. Shortly after they do, the patient's blood pressure improves.

Possible Spinal Cord Injuries
     Though it may be difficult for prehospital personnel to determine when a spinal cord injury is present, it is crucial to maintain a high index of suspicion and always address the possibility. In addition, first responders should always consider protecting the cervical spine region of a patient who exhibits neurological deficit after a traumatic insult. The spinal cord exits the cranium through the foramen magnum and travels down the narrow spinal canal. Any trauma to the cervical region that results in excessive hyperextension, flexion, rotation, distraction, axial loading or lateral bending may cause transection, bruising or swelling to the cord, and/or injury to the surrounding musculoskeletal structures of the cervical region.

     The higher the injury on the spinal cord, the greater the chance for a catastrophic outcome. The nerves responsible for innervating the chest wall and diaphragm exit the spinal cord from the cervical region. If affected, they will prohibit the ability of the chest wall to expand. This will pose a serious problem for the patient when attempting to breathe. Also, neurological impulses will no longer be able to travel to the target areas of the body, due to a transection or injury of the spinal cord. Injury to the spinal cord may present with neurological deficit, such as quadriplegia, paraplegia, paresthesia, incontinence and/or priapism.

     However, as reflected in this case, managing the spinal injury may not be the only challenge for prehospital providers. Here was a case where the patient experienced a spinal injury accompanied by shock resulting from the spinal injury. In prior columns we've addressed the importance of a systematic patient assessment approach and conducting a quick neurological assessment only after the ABCs have been completed. Let's take this opportunity to review neurogenic shock resulting from a spinal injury.

     Neurogenic shock is the loss of autonomic nervous system response. Neurological activity in the body is controlled by the brain, spinal cord and peripheral nerves. This system governs both voluntary and involuntary body processes. Control of involuntary processes (the autonomic nervous system) affects things we really don't think about—heart rate, blood vessel calibration, digestion, respiration, etc.

     The autonomic nervous system consists of the sympathetic and parasympathetic nervous systems. The sympathetic nervous system plays a role when the body is placed under stress; when stimulated, it results in the "fight or flight" response—reactions like increased heart and respiratory rates, increased blood pressure, blood vessel constriction, diaphoresis and other stress responses. The parasympathetic system has a complementary function governing the body's "rest and digest" response.

     The sympathetic nervous system is therefore an integral part of ensuring the body responds to stress. If an injury occurs to the spinal cord in areas where there are sympathetic nerve clusters and the sympathetic nerves are unable to transmit impulses to target areas, a loss of sympathetic response occurs. This may result in bradycardia, hypotension (due to vasodilation), decrease in respiratory rate, warm and dry skin, and other nonsympathetic responses. If the body loses its ability to engage a sympathetic response, this will lead to inadequate tissue perfusion, or shock.

     Keep in mind that neurogenic shock is not a true hypovolemic issue—it's a "pipe" issue. Three things must be intact to prevent inadequate tissue perfusion: 1) A working pump (heart); 2) adequate volume (blood); and 3) intact pipes (a working vascular system). In neurogenic shock, there is a problem with the pipes: They have lost the ability to vasoconstrict. This is why the providers in our example decided to administer a dopamine infusion only after a trial infusion of normal saline had been administered. Although the patient was exhibiting signs of neurogenic shock, we can't dismiss the fact that due to the mechanism of injury, a hypovolemic insult may have also been present.

     There may be times when, due to a lack of neurological deficits, a spinal injury may not be obvious to the prehospital provider. Therefore, a detailed assessment, a good patient history and the mechanism of injury should all be considered when deciding to immobilize a patient without evidence of a neurological deficit. Patients suspected of spinal injury with neurological deficit should be secured on a long spine board with a cervical collar. When immobilizing the patient to the spine board, it is important to immobilize the torso, pelvis, lower extremities and, finally, the head. By understanding the anatomy of the nervous system and the physiology of shock, and always executing a thorough assessment, you will be able to better manage the neurogenic shock patient.

Orlando J. Dominguez, Jr., MBA, FF/EMT-P, is chief of EMS and public information officer for Brevard County Fire Rescue in Rockledge, FL.