OBJECTIVE: To present electron micrographs of lung tissue obtained from a patient exposed to high ventilatory pressures in the context of pulmonary dysfunction and pulmonary hypertension. DESIGN: Case report. SETTING: Adult intensive care unit of a university-affiliated teaching hospital. PATIENTS: A patient exposed to high-pressure mechanical ventilation during support for acute respiratory distress syndrome; the acute respiratory distress syndrome in this case was secondary to septic shock. MEASUREMENTS AND MAIN RESULTS: Scanning electron micrographs of lung tissue, focusing on the internal alveolar surfaces. FINDINGS: Multiple gross disruptions of the alveolar walls, suggestive of stress fractures. CONCLUSION: High-pressure mechanical ventilation may promote fracturing of the alveolar blood:airspace barrier.