Pathophysiology of respiratory failure in neuromuscular diseases
Non-invasive Ventilation and Weaning: Principles and Practice, CRC Press, ss.331-339, 2010
- Yayın Türü: Kitapta Bölüm / Araştırma Kitabı
- Basım Tarihi: 2010
- Doi Numarası: 10.1201/b13434
- Yayınevi: CRC Press
- Sayfa Sayıları: ss.331-339
- Sağlık Bilimleri Üniversitesi Adresli: Evet
Özet
Respiratory failure is one of the most important causes of increased morbidity and mortality in patients with neuromuscular diseases. The pathophysiology of respiratory failure in these patients is complex and includes alveolar hypoventilation, impaired gas exchange or both. Alveolar hypoventilation can result from impaired control of breathing and increased mechanical load on the respiratory muscles. In most patients, however, respiratory muscle weakness is the main culprit for the development of alveolar hypoventilation. Impaired gas exchange results from ventilation/perfusion inequality or, less often, increased intrapulmonary shunt. These derangements in gas exchange occur when patients affected by neuromuscular diseases develop bulbar and expiratory muscle weakness. Weakness of the bulbar and expiratory muscles increases the risk for pulmonary aspiration, retention of secretions, and pneumonia. In addition, bulbar and expiratory muscle weakness can increase the likelihood of atelectasis in patients with inspiratory muscle weakness. Diagnosis of respiratory impairment frequently goes undetected in patients with neuromuscular diseases until ventilatory failure is precipitated by aspiration pneumonia or cor pulmonale. Diagnosis is delayed because limb muscle weakness prevents patients from exceeding their limited ventilatory capacity. In specific cases the lack of dyspnoea may reflect the difficulty in communicating symptoms because of cognitive impairment. It follows that the diagnosis of respiratory dysfunction resulting from neuromuscular diseases requires a high index of clinical suspicion and, in selected cases, the use of specific tests. In this chapter we discuss the multifaceted pathophysiology of respiratory failure in patients with neuromuscular diseases.