Respiratory Management Following Spinal Cord Injury - 20

RESPIRATORY MANAGEMENT FOLLOWING SPINAL CORD INJURY

intubation and surgical tracheostomy for mechanical ventilation, if possible. These include the acute complications of intubation itself, the maintenance of the body’s mechanism for filtering inspired air in the oro- and nasopharynx, as well as the chronic complications associated with tracheostomy tubes. In the acute setting, patients who have mild respiratory dysfunction (low vital capacity) may be managed by noninvasive means of ventilation (Tromans et al., 1998). To be effective, bulbar muscles must be intact, and the patient must be cooperative and otherwise medically stable. Most patients with SCI have intact bulbar function and are therefore good candidates. A concern about noninvasive ventilation is the potential for emesis and aspiration, especially in the acute setting when gastric emptying is slowed, which may increase the patient’s chance for acute respiratory distress syndrome (ARDS). If the facility staff do not have expertise in the use of noninvasive means of ventilation, however, it is prudent to intubate acutely injured patients immediately. For those individuals who require long-term mechanical ventilation, potential complications of tracheostomy tubes may include granulation formation, stomal infection, tracheomalacia, tracheal perforation, stenosis, fistula formation, decreased voice volume, and inability to perform glossopharyngeal breathing (Bach et al., 1991). The use of noninvasive means for ventilation, if suitable for the individual, can decrease these issues. Noninvasive intermittent positive pressure ventilation (NIPPV) can be delivered via oral, nasal, or oro-nasal interfaces, and can be used for full-time ventilation as well as in the sitting and supine position (Bach et al., 1990). Nasal interfaces can be used when a mouthpiece is not effective and during the night. Other negative pressure options can include the use of body ventilators, such as the iron lung, Porta-lung, cuirass, and “wrap” ventilators. Of these negative pressure body ventilators, only the cuirass can be used for ventilatory assistance in the seated position. Intermittent abdominal pressure ventilation can be used in seated patients, as it compresses the viscera, forcing exhalation, and then allows passive inhalation. Persons with chronic spinal cord injury with a tracheostomy tube can be decannulated and managed with noninvasive means of ventilation (Bach et al., 1991; Bach and Alba, 1993). In addition, the use of noninvasive ventilation may facilitate weaning from the ventilator (Tromans et al., 1998; Bach, 1991; Bach et al., 1993). The benefits of noninvasive ventilation, aside from the complications of the tracheostomy tube, include a decreased risk of infection, as the presence of a

foreign body in the patient’s trachea is avoided; a lower risk of hospital-associated pneumonia; and a greater likelihood of discharge to home.

Sleep-Disordered Breathing
21. Perform a polysomnographic evaluation for those patients with excessive daytime sleepiness or other symptoms of sleep-disordered breathing.
(Scientific evidence–V; Grade of recommendation–C; Strength of panel opinion–Strong)

Persons with chronic tetraplegia have a high prevalence of sleep-disordered breathing. Although subject inclusion criteria have varied across studies, most have reported 25–45% prevalence (Short et al., 1992; Cahan et al., 1993; McEvoy et al., 1995; Burns et al., 2000; Ayas et al., 2001). The prevalence of sleep-disordered breathing in acute tetraplegia has not been reported, although most patients show obstructive sleep apnea. Central sleep apnea appears to be relatively common as well (Short et al., 1992; McEvoy et al., 1995; Burns et al., 2000). Possible risk factors for sleep-disordered breathing in persons with SCI include obesity, neurological changes, and baclofen use (Burns et al., 2000; Burns et al., 2001; Ayas et al., 2001; Klefbeck et al., 1998), although these findings have not been consistent across all studies. When sleep-disordered breathing causes significant nocturnal desaturation, tetraplegic patients are predisposed to cognitive dysfunction, with deficits in attention, concentration, memory, and learning skills (Sajkov et al., 1998). Other ventilatory disorders that occur in people with SCI, such as chronic alveolar hypoventilation, are exacerbated during sleep and may have health consequences similar to sleep apnea. Finally, nocturnal ventilatory disorders are prevalent in patients with hypoxemic or hypercapneic respiratory failure, and obstructive sleep apnea may play a role in the development of atelectasis. Patients with signs and symptoms of sleepdisordered breathing, such as severe snoring or excessive daytime sleepiness without other causes, should undergo diagnostic evaluation. Full polysomnography with electroencephalographic monitoring is the most sensitive test for diagnosing sleep-disordered breathing in the general population. Additional signs that should prompt a polysomnographic evaluation include hypertension that is resistant to pharmacologic treatment and persistent nocturnal bradycardia. Nocturnal pulse oximetry may be adequate for detecting severe

Respiratory Management Following Spinal Cord Injury

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