title: Hypothermia attenuates vascular manifestations of ventilator-induced lung injury in rats.
abstract: Alveolar hemorrhage and pulmonary edema induced by mechanical ventilation are partly dependent on cardiac output. Because cardiac output is low during hypothermia, we hypothesized that hypothermia may protect against these vascular manifestations of ventilator-induced lung injury. Twenty-seven Sprague-Dawley rats were assigned to either normothermia (37 +/- 1 degrees C)-injurious ventilation (NT; n = 10), hypothermia (27 +/- 1 degrees C)- injurious ventilation (HT; n = 10), or nonventilated control ( n = 7). The two ventilated groups were subjected to injurious ventilation of peak airway pressure 30 cm H(2)O with zero end-expiratory pressure for 20 min. Compared with the NT group, the hemorrhage/congestion score of the lung (11.2 +/- 1.5 vs. 4.7 +/- 1.6; p < 0.001) and the ratio of wet/dry lung weight (6.1 +/- 0.8 vs. 5.0 +/- 0.1; p = 0.046) of the HT group were lower. Compared with the NT group, protein concentration (3,471 +/- 1,985 micro g/ml vs. 1,374 +/- 726 micro g/ml; p = 0.003) and lactate dehydrogenase level (0.43 +/- 0.22 U/ml vs. 0.18 +/- 0.1 U/ml; p = 0.046) in bronchoalveolar lavage fluid of the HT group were lower. Whereas pressure-volume curve was shifted to the right in the NT group after injurious ventilation, it was not shifted in the HT group. In conclusion, hypothermia in rats attenuated the degrees of vascular manifestations and alveolar epithelial injuries induced by injurious ventilation, and preserved the mechanical properties of the lung.
authors.affiliation: Division of Respiratory and Critical Care Medicine, Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea 138-600. cmlim@amc.seoul.kr
authors.forename: C-M
authors.initials: CM
authors.lastname: Lim
authors.forename: S-B
authors.initials: SB
authors.lastname: Hong
authors.forename: Y
authors.initials: Y
authors.lastname: Koh
authors.forename: S D
authors.initials: SD
authors.lastname: Lee
authors.forename: W S
authors.initials: WS
authors.lastname: Kim
authors.forename: D-S
authors.initials: DS
authors.lastname: Kim
authors.forename: W D
authors.initials: WD
authors.lastname: Kim
mesh_terms: D000818:Animals; D001784:Blood Gas Analysis; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D004195:Disease Models, Animal; D007036:Hypothermia, Induced; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D007958:Leukocyte Count; D008168:Lung / Q000033:anatomy & histology / Q000378:metabolism; D008171:Lung Diseases / Q000097:blood / Q000209:etiology* / Q000473:pathology; D055370:Lung Injury; D008297:Male; D009504:Neutrophils / Q000378:metabolism; D009929:Organ Size; D011175:Positive-Pressure Respiration; D011506:Proteins / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013990:Tidal Volume / Q000502:physiology; D017211:Treatment Failure; D012122:Ventilators, Mechanical / Q000009:adverse effects*
chemical_list: D011506:Proteins; D007770:L-Lactate Dehydrogenase