Effect of positive end-expiratory pressure on inflammatory response in oleic acid-induced lung injury and whole-lung lavage-induced lung injury.
OBJECTIVE
The present study investigated the effects of positive end-expiratory pressure (PEEP) on the inflammatory response in two different lung injury models: edematous lung induced by oleic acid (OA); and atelectatic lung induced by whole-lung lavage (LAV).


METHODS
Japanese white rabbits (n = 28) were allocated to one of the two lung injury (OA or LAV) groups, and each group was treated with intermittent positive pressure ventilation, using zero end-expiratory pressure (ZEEP) or PEEP (1 cm H(2)O above the lower inflection point [LIP]). Thus, the animals were divided into LAV-ZEEP, LAV-PEEP, OA-ZEEP, and OA-PEEP groups. Blood and bronchoalveolar lavage fluid (BALF) were sampled 3 h after ventilatory treatment to analyze interleukin (IL)-8 levels.


RESULTS
Pa(O) (2) was significantly decreased after the induction of lung injury, but was significantly higher in the PEEP groups compared to the ZEEP groups for each lung injury. Serum IL-8 levels were elevated in both experimental models. Serum IL-8 levels were significantly lower in LAV-PEEP than in LAV-ZEEP, whereas no difference was noted between OA-PEEP and OA-ZEEP. BALF IL-8 levels were lower in LAV-PEEP than in LAV-ZEEP. PEEP above LIP attenuated the elevation of IL-8 in BALF and serum in atelectatic lungs, but did not attenuate these increases in the edematous lungs.


CONCLUSIONS
These results suggest that the protective effects of PEEP on injured lungs may depend on the underlying lung pathology.
Nakazawa
Koichi
K
Department of Anesthesiology and Critical Care Medicine, Tokyo Medical and Dental University School of Medicine, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan.
Yokoyama
Kuninori
K
Yamakawa
Naoko
N
Makita
Koshi
K
D000704:Analysis of Variance; D000818:Animals; D001784:Blood Gas Analysis / Q000379:methods; D001794:Blood Pressure; D018893:Bronchoalveolar Lavage / Q000009:adverse effects* / Q000379:methods; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D004195:Disease Models, Animal; D016209:Interleukin-8 / Q000032:analysis / Q000097:blood; D019301:Oleic Acid; D011014:Pneumonia / Q000139:chemically induced / Q000473:pathology / Q000628:therapy*; D011175:Positive-Pressure Respiration / Q000379:methods*; D011506:Proteins / Q000378:metabolism; D001261:Pulmonary Atelectasis / Q000209:etiology / Q000378:metabolism / Q000628:therapy*; D011654:Pulmonary Edema / Q000139:chemically induced / Q000473:pathology / Q000628:therapy*; D011817:Rabbits; D012121:Respiration, Artificial / Q000379:methods; D012128:Respiratory Distress Syndrome / Q000517:prevention & control; D012965:Sodium Chloride / Q000008:administration & dosage / Q000009:adverse effects; D013997:Time Factors; D014139:Tracheostomy
D016209:Interleukin-8; D011506:Proteins; D019301:Oleic Acid; D012965:Sodium Chloride