Discuss the pathophysiology of ventilatory failure in patients with neuromuscular disease or chest wall deformities.
Discuss the indications for invasive and noninvasive ventilation in this patient population.
Discuss initial ventilator settings for invasive and noninvasive ventilatory support in this patient population.
Discuss monitoring during and weaning from ventilatory support for patients with neuromuscular disease.
Discuss the use of the in-exsufflator in patients with neuromuscular disease.
Patients with neuromuscular disease or chest wall deformities represent a small percentage of patients receiving ventilatory support. However, they also represent a large percentage of patients requiring long-term ventilatory support. As these patients usually have normal lungs and the reason for ventilatory assistance is an inability to generate sufficient muscular effort to ventilate, providing mechanical ventilation is much easier in this group than with other groups of patients.
The neurorespiratory system includes the central nervous system control centers and feedback mechanisms, spinal cord, motor nerves, and the respiratory muscles that affect chest wall and lung movement. Neuromuscular respiratory failure can be due to dysfunction of the central or the peripheral nervous system (Tables 22-1 and 22-2). The three main components of neuromuscular respiratory failure are inability to ventilate, inability to cough, and aspiration risk. This group of patients can be divided into two general categories—those with a relatively rapid (days to weeks) onset of neuromuscular weakness and those in which neuromuscular weakness is progressive and not reversible.
Table 22-1Diseases of the Central Nervous System Associated With Respiratory Dysfunction ||Download (.pdf) Table 22-1 Diseases of the Central Nervous System Associated With Respiratory Dysfunction
|Cerebral cortex ||Brainstem ||Basal ganglia ||Spinal cord |
Infarction ("locked-in syndrome")
Progressive bulbar palsy
Primary alveolar hypoventilation
Infarction or hemorrhage
Motor neuron disease
Table 22-2Diseases of the Peripheral Nervous System Associated With Respiratory Dysfunction ||Download (.pdf) Table 22-2 Diseases of the Peripheral Nervous System Associated With Respiratory Dysfunction
|Motor nerves ||Neuromuscular junction ||Myopathies |
Amyotrophic lateral sclerosis
Spinal muscular atrophy
Toxins (eg, lithium, arsenic, gold)
Lambert-Eaton myasthenic syndrome
Polymyositis and dermatomyositis
Nemaline body myopathy
Acid maltase deficiency