Chapter 15: Acute Respiratory Failure

Acute respiratory failure represents the inability of the respiratory system to maintain adequate gas exchange, either through insufficient oxygenation or inadequate carbon dioxide elimination, and stands as one of the most frequent diagnoses requiring critical care admission with significant mortality implications. The condition manifests in two distinct presentations: Type 1 failure involves hypoxemia with arterial oxygen pressure below 60 millimeters of mercury despite relatively normal carbon dioxide levels, typically resulting from processes such as hypoventilation, intrapulmonary shunting, ventilation-perfusion mismatch, or diffusion impairment across the alveolar-capillary membrane. Type 2 failure is characterized by hypercapnia with elevated carbon dioxide levels, stemming from inadequate minute ventilation caused by central nervous system depression, neuromuscular dysfunction, or chest wall mechanics abnormalities. Acute respiratory distress syndrome represents the most severe manifestation, defined by acute bilateral lung inflammation with profound refractory hypoxemia that fails to respond adequately to supplemental oxygen and progresses through distinct pathological phases including exudative inflammation, proliferative fibrosis development, and ultimate alveolar obliteration. Management of acute respiratory distress syndrome incorporates lung-protective mechanical ventilation employing reduced tidal volumes to prevent barotrauma, positive end-expiratory pressure to recruit collapsed alveoli, prone positioning to optimize ventilation-perfusion relationships, and judicious fluid restriction. Specific clinical scenarios require tailored approaches, including careful oxygen titration in chronic obstructive pulmonary disease exacerbations to preserve hypoxic respiratory drive, aggressive bronchodilation and corticosteroid therapy in severe asthma, systematic prevention bundles for ventilator-associated pneumonia through head-of-bed positioning and oral hygiene, and thromboembolism prophylaxis for pulmonary embolism management. Nursing care emphasizes maintaining airway patency, optimizing oxygen delivery through strategic positioning such as dependent placement of healthier lung segments, reducing metabolic oxygen demand through rest and symptom management, and continuous monitoring using pulse oximetry and arterial blood gas analysis to detect early deterioration.