Prolonged Mechanical Ventilation in Children with Neuromuscular Disease

Respiratory muscle involvement in neuromuscular diseases (NMDs) is the base of breathing abnormalities in affected children. Imbalanced ventilation observed in NMDs is the result of respiratory muscle weakness, increased respiratory load due to thoracic stiffness, and bulbar dysfunction. As breathing is physiologically less efficient during sleep, hypoventilation and sleep-disordered breathing (SDB) will be the initial signs of respiratory insufficiency in children with NMDs, but, with the progression of the disease, diurnal hypoventilation may also occur. The role of prolonged mechanical ventilation (PMV) is then to assist or “replace” the weakened respiratory muscles, in order to correct alveolar hypoventilation by maintaining a minute ventilation sufficient to ensure optimal gas exchange. Noninvasive ventilation (NIV) is often the earliest type of respiratory support in NMD patients. NIV is electively initiated in children with a reduction in pulmonary function assessed by volitional noninvasive tests able to measure lung volumes, maximal static pressures, and flows. NIV is also indicated when clinical signs of unrefreshing sleep are detected, or in case of acute respiratory failure requiring any type of ventilation. NIV is usually delivered through a nasal or a facial mask, and a ventilator with a bi-level mode and a backup respiratory rate. With disease progression, NIV may be required all day long, preferentially by means of a mouthpiece that allows speech and eating. When bulbar involvement makes airway severely unstable or NIV has failed to correct hypoventilation, tracheostomy placement and initiation of invasive mechanical ventilation (IMV) should be considered. In NMD patients, early use of PMV and mechanical or manual techniques meant to improve airway clearance prevents thoracic deformities, corrects gas exchange, and reduces the frequency of hospitalization, and it is associated with increased sleep efficiency and longer survival. Children with NMDs should be managed by an expert pediatric multidisciplinary team and transitioned to adult pulmonary care facilities, which will be facing new challenges, such as health complications or social problems not previously seen. Therefore, the implementation of healthcare programs that enhance the quality of life of young adults with NMDs and chronic respiratory failure is necessary.