Prehospital Care

The prehospital treatment of patients with spinal cord injury involves recognition of patients at risk, proper triage, and early care. All patients who have complaints of neck or back pain or who have tenderness on prehospital assessment must be presumed to have a spine injury until proven otherwise. Traditionally, all patients with significant injury above the clavicle are also presumed to have cervical spine injury regardless of related complaints. All patients with neurologic complaints must be presumed to have a spinal cord injury. Sometimes this is obvious, as in a patient with flaccid paraplegia. More often, symptoms are much more subtle (numbness or tingling in an extremity). Appropriate triage is imperative, as the results of the treatment for spinal cord injury are somewhat time-related. Therefore, initial triage to a center that is capable of rapid diagnostics and therapeutics is essential to optimize outcome following spinal cord injury.

Triage can be difficult. Patients may be asymptomatic or may have suffered a concomitant head injury that makes them unable to describe their injuries and hence does not allow for neurologic assessment in the field. Other injuries may preclude accurate hospital assessment. The mechanism of injury is an important criterion on which prehospital providers can rely. High-speed or roll-over vehicular accidents are commonly associated with spinal injury. Even more commonly, axial loading injuries such as substantial falls from a height produce spinal cord injuries, generally in the area of the thoracolumbar junction. Diving and surfing accidents, where force is transmitted through the cranium and into the cervical spine, typically produce cervical spine injuries. Any patient at risk by mechanism of injury must be presumed to have a spinal cord injury. While this may result in a substantial rate of overtriage, the consequences of undertriage can be devastating.

Prehospital care for spinal injuries involves immobilization of the entire spine and initial fluid therapy as proposed by the American College of Surgeons. 15 The entire cervical spine can be immobilized with a rigid cervical collar supplemented with sandbags and tape. The thoracic and lumbar spine can be immobilized utilizing a long backboard. Patients are "papoosed" onto the boards to maintain spinal alignment. Patients should be transported completely immobilized. Fluid therapy is begun and tailored to avoid hypotension. While there is little scientific evidence to support any single target for systolic or mean arterial blood pressure in patients with spinal cord injuries, a mean arterial pressure of 65 to 70 mmHg seems a reasonable target. Optimal perfusion of the spinal cord is one of the therapies that can be implemented in the field to lessen the chances of secondary spinal injury.

Prehospital personnel must balance the issues of time of transport with the level of expertise of the various hospitals within their system. All efforts should be made to deliver patients with symptomatic spinal injuries to the areawide spine center. Delays engendered by transport to a different site can be costly. Clearly, patients who are not hemodynamically stable must be taken to the closest available hospital. ED Stabilization

ED evaluation should not differ substantially from any patient with multiple injuries (see C.h.a.p, 2.4.3). It involves a stepwise search for immediately life-threatening injuries. Airway concerns are paramount. Real consideration should be given to immediate airway control in patients with cervical spine injuries no matter how stable they seem at the time of presentation. The higher the level of spinal injury, the more compelling the indication for early airway intervention. The roots of the phrenic nerve, which supplies the diaphragm, emerge at the third, fourth, and fifth cervical vertebral levels. Thus, any patient with an injury at C5 or above should be intubated. It may be prudent to intubate parents with cervical cord lesions even below this level. Significant spinal cord edema may progress rostrally to involve the roots of the phrenic nerve. Many patients can initially support ventilatory function utilizing intercostal muscles or abdominal breathing, but they eventually tire and then develop respiratory failure. As the evaluation process for these patients often involves transport outside of the ED, the authors feel strongly that early airway control is the safest route. Patients who develop respiratory failure in the CT scanner or the MRI suite may suffer respiratory arrest before it can be recognized and the airway secured. This risks anoxic brain damage and worsening spinal cord injury from hypoxia.

AIRWAY It is important to try to perform a complete neurologic assessment if possible before patients are intubated and sedated. The spine must be kept immobilized while the airway is managed. In general, this is accomplished using orotracheal intubation with in-line cervical stabilization (without distraction force) and cricoid pressure. Nasal intubation can be performed in patients while maintaining spine immobilization, though it is not our preferred method and presents considerable difficulties. Nasal intubation is generally a blind technique. Virtually all patients with potential cervical spine trauma require sedation before nasal intubation can be accomplished; but if respirations become substantially depressed, nasotracheal intubation may not be possible. If patients are inadequately prepared they may resist intubation. Motion of an unstable fracture can worsen spinal injury. If patients are over-sedated, they may become hypoxic and lose the ability to protect the airway. Also, nasal intubation is performed with a smaller endotracheal tube, which can compromise respiratory therapy later during the hospitalization. Fiberoptic bronchoscopy (FOB) may be required, particularly in those with pulmonary injuries or significant atelectasis. Bronchoscopy can be used for diagnostic purposes or to facilitate removal of inspissated mucous plugs or blood. A relatively large endotracheal tube (8.0 mm or greater in size) is needed during FOB in order to ensure that ventilation is not compromised during the procedure. An 8.0 mm endotracheal tube is often too large for nasotracheal intubation. In addition, the limiting factor in minimizing tube size is the increasing respiratory resistance to gas flow imposing increased work for the patient with each spontaneous breath. Thus, the work of breathing is greater with tubes of 6 to 7 mm internal diameter, sometimes used for nasal intubation, than with tubes of 8 mm or greater internal diameter. The most limiting aspect of nasal intubation is the inability to move the cervical spine to attain the "sniff" position, optimal for the procedure. Finally, nasal intubation increases the risk of sinusitis, which later becomes symptomatic.

Nasal intubation with fiberoptic guidance is a useful technique. It does carry many of the concerns of nasal intubation previously mentioned. It is, however, not a blind technique and can be directed, maximizing the chances of successful airway management.

Patients with spinal cord injuries often have concomitant chest injuries and/or abdominal injuries. A careful survey must be completed for each of these. Respiratory failure in a spinal cord-injured patient can certainly come from tension pneumothorax or blood loss into the chest.

HYPOTENSION Following airway stabilization, hemodynamic stability is the most pressing concern. Fluid therapy is generally the treatment of choice to support cardiovascular functioning. Patients with spinal cord injuries often present with hypotension, which must be differentiated as to its cause: spinal cord injury, blood loss, or both. Injury to the spinal cord at the level of the cervical or thoracic vertebrae causes sympathetic denervation. There is a loss of a-adrenergic tone and dilatation of the arterial and venous vessels. Elimination of sympathetic arterial tone results in hypotension. Systemic vascular resistance is reduced. Loss of sympathetic innervation to the heart (T1 through T4 cord levels) leaves the parasympathetic cardiac innervation via the vagus nerve unopposed, resulting in bradycardia. While it is true that neurogenic shock is associated with bradycardia, it should never be assumed that a patient with hypotension and bradycardia is suffering from isolated neurogenic shock. Vital signs are often nonspecific. Patients with neurogenic shock may have concomitant hemorrhagic shock and may not be able to mount a tachycardic response. Blood loss must be presumed to be the cause of hypotension until proven otherwise. In general, patients with neurogenic shock are warm, peripherally vasodilated, and bradycardic. They seem to tolerate hypotension relatively well. This makes some sense, as peripheral oxygen delivery is presumably normal. They have incurred mechanical sympathectomy, thus cardiovascular function is not impaired.

The mechanism of injury is important in determining whether hypotension is from spinal cord injury or blood loss. Soderstrom et al. have demonstrated that 70 percent of patients with blunt trauma have hypotension secondary to the spinal cord injury.16 However, in almost one-third of the patients, blood loss at least partly explained the hemodynamic instability. Hypotension from spinal cord injury is highly unusual in patients with penetrating injury. Zipnick et al. have demonstrated that over 90 percent of hypotensive patients with penetrating spinal cord injury have blood loss to at least partly explain their hypotension. 17

In all patients, a rapid search for potential blood loss should be undertaken. A chest x-ray will identify blood loss within the thorax. Retroperitoneal blood loss can come from concomitant pelvic fractures or may be secondary to lumbar arterial bleeding from spine fractures, especially in patients with substantial falls from a height. This can be a difficult diagnosis to make. Every patient with a spinal fracture should have an abdominal investigation. In hemodynamically unstable patients, CT

scanning is too time-consuming; therefore ultrasound or diagnostic peritoneal lavage should be used (see Chap 252). Retroperitoneal bleeding should be suspected in patients without evidence of intraabdominal blood loss who develop abdominal distention or tenderness. 12 Plain x-rays that demonstrate spinal fractures should help with the diagnosis. Angiography may be necessary for both diagnosis and treatment of ongoing bleeding.

NEUROLOGIC EXAMINATION Once patients are stabilized and other life-threatening injuries have been excluded or treated, a detailed neurologic examination should be performed if still possible. Details of history include whether the patient has had a loss of consciousness. Ask about the presence or absence of sensory or motor symptomatology in the field. A patient who was asymptomatic in the field and has neurologic deterioration in the ED requires emergent therapy. The presence of neck or back pain, or urinary or fecal incontinence clearly defines the patient at risk for spinal cord injury.

Physical examination should delineate the level of spinal cord injury, if any ( Fig 248-7). Document the initial neurologic performance. If patients deteriorate later, a complete initial neurologic examination must be documented for comparison purposes. The presence or absence of neck or back tenderness should be noted. A careful motor examination should be performed. Motor function for muscle groups should be tested and recorded on a scale of 0 to 5 ( Table.. ..2.48.-2). The level of sensory loss should be determined. Gross proprioception or vibratory function must be investigated to examine posterior column function. Deep tendon reflexes should be tested. Anogenital reflexes should also be tested, because "sacral sparing" with preservation of the reflexes denotes an incomplete spinal cord level even if the patient has complete sensory and motor loss. The neurosurgeon must be notified emergently. To test the bulbocavernosus reflex, squeeze the penis to determine whether the anal sphincter simultaneously contracts, and assess rectal tone at the same time. Priapism implies a complete spinal cord injury. The cremasteric reflex is tested by running a pin or a blunt instrument up the medial aspect of the thigh. If the scrotum rises, there is some spinal cord integrity. The area around the anus should be tested with a pin. An "anal wink" (contraction of the anal musculature) indicates some sacral sparing.

FIG. 248-7. Spinal cord level. This level can be delineated by physical examination, including a detailed neurologic examination.

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