Chapter 32: Acute Respiratory Failure & ARDS

Acute respiratory failure manifests as either hypoxemic failure, characterized by inadequate oxygenation with arterial oxygen levels below 60 mmHg, or hypercapnic failure, involving carbon dioxide retention above 50 mmHg with accompanying acidosis. The pathophysiology underlying hypoxemic failure includes ventilation-perfusion mismatch, intrapulmonary shunting, diffusion impairment, and alveolar hypoventilation, while hypercapnic failure results from central nervous system depression, neuromuscular disorders, chest wall abnormalities, or severe airway obstruction. Clinical assessment reveals progressive respiratory distress with dyspnea, accessory muscle use, altered mental status, and eventual cardiovascular compromise. Management strategies encompass oxygen therapy, positive pressure ventilation including continuous positive airway pressure and mechanical ventilation, secretion mobilization techniques, and pharmacological interventions with bronchodilators, corticosteroids, and supportive medications. Acute respiratory distress syndrome represents a severe inflammatory condition affecting the alveolar-capillary membrane, progressing through distinct exudative, proliferative, and fibrotic phases with characteristic refractory hypoxemia and bilateral pulmonary infiltrates. Treatment protocols emphasize lung-protective ventilation strategies with low tidal volumes, optimal positive end-expiratory pressure, prone positioning, and restrictive fluid management. Advanced interventions may include extracorporeal membrane oxygenation for refractory cases, while comprehensive nursing care addresses ventilator-associated pneumonia prevention, nutritional support, psychological support, and recognition of multi-organ dysfunction syndrome complications.