Restrictive Respiratory Diseases and Lung Transplantation

Restrictive respiratory diseases encompass a broad spectrum of conditions characterized by reduced lung volumes, particularly total lung capacity, while preserving normal or elevated expiratory flow rates. These disorders arise from two primary mechanisms: intrinsic parenchymal injury and extrinsic compression of lung tissue. Acute intrinsic forms include various types of pulmonary edema—cardiogenic, noncardiogenic, negative pressure, neurogenic, and reexpansion—alongside emerging conditions such as vaping-associated lung injury and viral pneumonitis. Chronic intrinsic restrictive disease, often termed interstitial lung disease, involves diffuse parenchymal scarring from conditions like sarcoidosis and hypersensitivity pneumonitis, characterized by markedly reduced functional residual capacity that severely limits oxygen stores and tolerance of apnea. Extrinsic restrictive disease stems from mechanical impedance to lung expansion through thoracic factors including chest wall deformities, pleural disorders, and mediastinal masses, or through extrathoracic mechanisms such as neuromuscular weakness, obesity, pregnancy, and abdominal distension. Acute respiratory failure and acute respiratory distress syndrome represent critical deteriorations requiring immediate mechanical ventilation with protective lung strategies employing low tidal volumes and judicious positive end-expiratory pressure titration. Perioperative anesthesia management demands recognition that supine positioning and general anesthesia further compromise functional residual capacity in these already-limited patients, necessitating elevated inspiratory pressures and careful drug selection to avoid prolonged respiratory depression. Lung transplantation remains the definitive intervention for end-stage restrictive and obstructive lung diseases, with sequential bilateral and heart-lung procedures offered depending on underlying pathology. A critical physiologic consequence of transplantation is denervation of the graft, which eliminates the protective cough reflex below the tracheal anastomosis and substantially elevates the risk of silent aspiration and nosocomial infection. Chronic rejection manifests as bronchiolitis obliterans, an irreversible progressive airflow obstruction. Management of transplant recipients requires strict infection control, heightened vigilance for acute and chronic rejection, meticulous fluid balance to prevent graft edema, and preferential use of regional anesthesia to preserve airway reflexes and facilitate secretion clearance.