Dynamic alveolar mechanics in four models of lung injury

• Published in: Intensive care medicine Vol. 32; no. 1; pp. 140 - 148
• Main Authors: DIROCCO, Joseph D, PAVONE, Lucio A, CARNEY, David E, LUTZ, Charles J, GATTO, Louis A, LANDAS, Steve K, NIEMAN, Gary F
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 01.01.2006; Berlin Springer Nature B.V
• Subjects: Acute respiratory distress syndrome; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Animals; Artificial respiration; Biological and medical sciences; Care and treatment; Causes of; Diagnosis; Disease Models, Animal; Emergency and intensive respiratory care; Hemodynamics; Hypoxia - physiopathology; Injuries of the thorax. Foreign bodies. Diseases due to physical agents; Intensive care medicine; Lipopolysaccharides; Male; Medical sciences; Oleic Acid; Prospective Studies; Pulmonary Alveoli - physiopathology; Pulmonary Edema - pathology; Pulmonary Gas Exchange; Rats; Rats, Sprague-Dawley; Respiration, Artificial - adverse effects; Respiratory Distress Syndrome, Adult - etiology; Respiratory Distress Syndrome, Adult - physiopathology; Respiratory Mechanics; Risk factors; Traumas. Diseases due to physical agents; United States; Acute respiratory distress syndrome; Lung disease; Acute lung injury; Ventilator; Oxygen; Intensive care; Respiratory disease; Ventilator-induced lung injury; Hypoxemia; Oleic acid; Respiratory distress; Alveolar mechanics; Resuscitation
• ISSN: 0342-4642; 1432-1238
• DOI: 10.1007/s00134-005-2854-3

To determine whether pathological alterations in alveolar mechanics (i.e., the dynamic change in alveolar size and shape with ventilation) at a similar level of lung injury vary depending on the cause of injury. Prospective controlled animal study in a university laboratory. 30 male Sprague-Dawley rats (300-550 g). Rats were separated into one of four lung injury models or control (n=6): (a) 2% Tween-20 (Tween, n=6), (b) oleic acid (OA, n=6), (c) ventilator-induced lung injury (VILI, PIP 40/ZEEP, n=6), (d) endotoxin (LPS, n=6). Alveolar mechanics were assessed at baseline and after injury (PaO2/FIO2 <300 mmHg) by in vivo microscopy. Alveolar instability (proportional change in alveolar size during ventilation) was used as a measurement of alveolar mechanics. Alveoli were unstable in Tween, OA, and VILI as hypoxemia developed (baseline vs. injury: Tween, 7+/-2% vs. 67+/-5%; OA: 3+/-2% vs. 82+/-9%; VILI, 4+/-2% vs. 72+/-5%). Hypoxemia after LPS was not associated with significant alveolar instability (baseline vs. injury: LPS, 3+/-2 vs. 8+/-5%). These data demonstrate that multiple pathological changes occur in dynamic alveolar mechanics. The nature of these changes depends upon the mechanism of lung injury.