Chapter 42. Restrictive Disease of the Respiratory System and the Abdominal Compartment Syndrome

• Scoliotic curves greater than 100° may cause dyspnea; curves greater than 120° are associated with alveolar hypoventilation and cor pulmonale.
• Most patients with chest wall deformity survive their first episode of acute respiratory failure. Common precipitants include upper and lower respiratory tract infections and congestive heart failure.
• Biphasic positive airway pressure may be effective in patients with acute hypercapnic respiratory failure.
• Low tidal volumes and high respiratory rates likely minimize the risk of barotrauma during mechanical ventilation; however, gradual institution of anti-atelectasis measures may improve gas exchange and static compliance.
• Nocturnal hypoxemia is common and may contribute to cardiovascular deterioration; routine polysomnography is recommended.
• Strategies for management of patients with chronic ventilatory failure include daytime intermittent positive pressure ventilation, nocturnal noninvasive ventilation, and ventilation through tracheostomy.
• Abdominal compartment syndrome (ACS) is caused by an acute increase in intra-abdominal pressure resulting from a number of surgical and medical conditions.
• By elevating the diaphragm and decreasing respiratory system compliance, ACS causes a restrictive defect. However, ACS affects a number of other organs and may cause multiorgan system failure.
• Diagnosis relies on measurement of intra-abdominal bladder pressure and identification of organ dysfunction.
• The abdomen should be decompressed before critical organ dysfunction develops.
• Failure to recognize and treat ACS portends a poor prognosis.
• Acute deterioration in respiratory status can occur from disease progression or a number of other infectious and noninfectious processes.
• Patients with idiopathic pulmonary fibrosis admitted to the ICU with acute respiratory failure have an extremely poor prognosis.
• If mechanical ventilation is deemed appropriate, the use of low tidal volumes and high respiratory rates during mechanical ventilation likely minimizes ventilator-induced lung injury.
• Idiopathic pulmonary fibrosis is typically refractory to drug treatment.
• Lung transplantation is a viable option in selected patients with end-stage fibrosis.

Thoracic cage deformity and pulmonary fibrosis both result in a restrictive limitation to breathing. Although relatively rare in the context of pulmonary intensive care, these disorders present unique challenges that complicate ICU management. More commonly a tense and distended abdomen decreases thoracic volume and respiratory system compliance. In this chapter, we describe the pathophysiologic derangements in cardiopulmonary function associated with these disorders and how they affect management during acute illness. A primary goal of this chapter is to offer a strategy for cardiovascular management and mechanical ventilation that minimizes the risk of ventilator-induced complications and maximizes the chance for early, successful extubation.

Although a number of disorders can deform and restrict the movement of the respiratory system (Table 42-1), kyphoscoliosis (KS) is the prototypical cause of severe thoracic deformity. Kyphoscoliosis is the combination of kyphosis (posterior deformity of the spine) and scoliosis (lateral deformity of the spine). It is far more common than isolated cases of kyphosis or scoliosis, placing as many as 200,000 people in the United States at risk of developing respiratory failure.1 Most cases are idiopathic and begin in childhood. Other cases result from congenital defects, poliomyelitis, thoracoplasty, syringomyelia, vertebral and spinal cord tumors, ...