Effect of lung-protective ventilation on severe Pseudomonas aeruginosa pneumonia and sepsis in rats

• Published in: American journal of physiology. Lung cellular and molecular physiology 2004-08, Vol.287 (2), p.L402-L410
• Main Authors: Kurahashi, Kiyoyasu, Ota, Shuhei, Nakamura, Kyota, Nagashima, Yoji, Yazawa, Takuya, Satoh, Minako, Fujita, Asako, Kamiya, Ritsuko, Fujita, Eri, Baba, Yasuko, Uchida, Kanji, Morimura, Naoto, Andoh, Tomio, Yamada, Yoshitsugu
• Format: Article
• Language: English
• Subjects: Animals; Bacteremia - etiology; Bacteremia - prevention & control; Carbon Dioxide - blood; Male; Partial Pressure; Pneumonia, Bacterial - therapy; Positive-Pressure Respiration - adverse effects; Positive-Pressure Respiration - methods; Pseudomonas aeruginosa; Pseudomonas Infections - therapy; Rats; Rats, Sprague-Dawley; Sepsis - etiology; Sepsis - prevention & control; Severity of Illness Index
• ISSN: 1040-0605; 1522-1504
• DOI: 10.1152/ajplung.00435.2003

Departments of 1 Anesthesiology and Critical Care Medicine, 2 Molecular Pathology and Oncology, and 3 Cellular Pathobiology, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa, Japan 236-0004 Submitted 5 December 2003 ; accepted in final form 19 April 2004 Pneumonia caused by Pseudomonas aeruginosa carries a high rate of morbidity and mortality. A lung-protective strategy using low tidal volume (V T ) ventilation for acute lung injury improves patient outcomes. The goal of this study was to determine whether low V T ventilation has similar utility in severe P. aeruginosa infection. A cytotoxic P. aeruginosa strain, PA103, was instilled into the left lung of rats anesthetized with pentobarbital. The lung-protective effect of low V T (6 ml/kg) with or without high positive end-expiratory pressure (PEEP, 10 or 3 cmH 2 O) was then compared with high V T with low PEEP ventilation (V T 12 ml/kg, PEEP 3 cmH 2 O). Severe lung injury and septic shock was induced. Although ventilatory mode had little effect on the involved lung or septic physiology, injury to noninvolved regions was attenuated by low V T ventilation as indicated by the wet-to-dry weight ratio (W/D; 6.13 ± 0.78 vs. 3.78 ± 0.26, respectively) and confirmed by histopathological examinations. High PEEP did not yield a significant protective effect (W/D, 4.03 ± 0.32) but, rather, caused overdistension of noninvolved lungs. Bronchoalveolar lavage revealed higher concentrations of TNF- in the fluid of noninvolved lung undergoing high V T ventilation compared with those animals receiving low V T . We conclude that low V T ventilation is protective in noninvolved regions and that the application of high PEEP attenuated the beneficial effects of low V T ventilation, at least short term. Furthermore, low V T ventilation cannot protect the involved lung, and high PEEP did not significantly alter lung injury over a short time course. acute lung injury; ventilator-induced lung injury; lung protective strategy; cytokines; bacterial toxins Address for reprint requests and other correspondence: K. Kurahashi, 3-9, Fukuura, Kanazawa-ku, Yokohama, Japan, 236-0004 (E-mail: kiyok{at}med.yokohama-cu.ac.jp )