6533b7d1fe1ef96bd125d583

RESEARCH PRODUCT

Neuromuscular and Chest Wall Diseases in Pregnancy

subject

description

Patients with severe respiratory muscle impairment, in particular when vital capa-city is below 60% of the predicted normal values, are often discouraged frombecoming pregnant for fear of respiratory complications and the need for tra-cheostomy and invasive mechanical ventilation (1). A growing fetus can impairthe functioning of weak diaphragms resulting in lower vital capacity and respira-tory reserve and impair cough function. In addition, there is increased oxygenconsumption and ventilation requirement. Complications in pregnancy and theneed for analgesics and anesthesia during labor and delivery can also cause orexacerbate ventilatory failure.Neuromuscular DiseasesNeuromuscular diseases (NMD) are those affecting motor unit (upper and lowermotor neuron, neuromuscular junction, and muscle) (Table 15.1). These processesare characterized by a progressive muscle weakness. The main causes of morbidityand mortality in neuromuscular patients are respiratory problems due to respira-tory muscles weakness (2). Inspiratory, expiratory, and upper airway (bulbar)muscles are involved, resulting in a progressive alveolar hypoventilation, decreasein cough capacity, and swallowing dysfunction with episodes of aspiration (3).Alveolar hypoventilation initially occurs during rapid eye movement (REM)sleepwhenrespiratorymuscleinhibitionandadecreaseinrespiratoryoutputoccurin patients with a weak diaphragm. As the disease progresses, hypoventilationextends to non-REM sleep and finally to wakefulness (4). The progressive declinein respiratory muscle function also produces a decrease in cough capacity, whichcan become ineffective. This results in atelectasis, increased work of breathing dueto impairment in lung compliance because of retained respiratory secretions, andrepetitive chest infections (5).