Respirator management of sepsis-related respiratory failure

The first description of acute respiratory distress syndrome (ARDS) in adults appeared in 1967 and was characterized by dyspnea, hypoxemia, diffuse alveolar infiltrates, and reduced respiratory system compliance. ARDS and acute lung injury (ALI) syndrome have no specific treatment, only supportive care: treating the underlying cause, when possible, and using mechanical ventilation. Historically, mechanical ventilation applied normal/large tidal volumes and low levels of positive end-expiratory pressure (PEEP). Experimental data showed that a high-volume, high-pressure ventilation strategy may lead to lung lesions indistinguishable from ARDS. Subsequent randomized clinical trials showed improved survival using low tidal volumes (6 vs 12 mL/kg ideal body weight) and limiting plateau pressure to 30 cm H ₂O, although the optimal level of PEEP remains controversial. Prone positioning should be reserved for severely ill patients. Inhaled nitric oxide, which is a pulmonary vasodilator with anti-inflammatory properties, is associated with limited improvement in oxygenation without improvement in survival.