Neuromuscular Respiratory Failure

Abstract

tion to airway clearance will aid in the prevention or delay of respiratory failure in these chronically ill patients who usually have an ineffective cough. Manual percussion and postural drainage with deep suction can be benefi cial. The use of a mechanical in–exsuffl ator (cough assist device) has been found to be helpful in improving airway clearance. In a retrospective study of 62 children with neuromuscular disease who used the mechanical in–exsuffl ator in the home setting, 90% found it to be effective in promoting airway clearance and preventing atelectasis and pneumonia [1]. This device has been demonstrated to potentially aid physicians and respiratory therapy staff in successfully weaning such patients from mechanical ventilatory support. Bach et al. have reported successful use of a protocol-driven approach to extubation in spinal muscular atrophy type 1 (SMA-1) patients using a combination of the mechanical in–ex-suffl ator and nasal positive pressure ventilation [2,3] A similar protocol has been reported for patients with Duchenne muscular dystrophy (DMD) [4]. In either circumstance, strict attention to airway clearance is the most important goal for preventing respiratory failure or aiding the recovery from an episode of respiratory failure in patients with chronic neuromuscular disorders. The decision to move from noninvasive ventilation to tracheal intubation for treatment of an acute event must be made with the understanding that there is a strong possibility of long-term ventilator dependence and tracheotomy for patients with progressive neuromuscular disease. In a questionnaire study of pediatric intensivists, physiatrists, and neurologists regarding attitudes about intervention for acute respiratory distress in a child with SMA-1, there was a wide variation in practice among specialties. Intensivists and neurologists were more likely than physiatrists to support noninvasive mechanical ventilation (NIMV) for both acute and chronic management, whereas physiatrists were more likely to support tracheal intubation/tracheostomy for these patients and less likely to promote comfort care only [5]. In another retrospective study of 56 SMA-1 children with respiratory failure presenting before 2 years of age, outcomes were compared for three groups: 16 children with tracheostomy, 33 children with nocturnal NIMV and cough assist plus tracheal intubation for acute infections, and 7 children who died of respiratory failure after tracheal intubation or tracheostomy was rejected [3]. Those children with tracheostomies had fewer hospitalizations before the age of 3 years, but this group also had more hospitalizations after the age of 5 years compared with those children using NIMV. Fifteen of the children with Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219 Therapeutic Principles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219 Anatomy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220 Force–Length Relationship . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220 Elastic Properties of the Chest Wall. . . . . . . . . . . . . . . . . . . . . . . . 220 Growth and Development. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221 Assessment of Chest Wall Function . . . . . . . . . . . . . . . . . . . . . . . . 222 Disease Classifi cations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226