title: Prophylactic effects of dexamethasone in lung injury caused by hyperoxia and hyperventilation.
abstract: To determine if prophylactic corticosteroids would prevent acute lung injury caused by hyperoxia and barotrauma, 29 piglets (1.2 +/- 0.3 kg, 1-2 days of age) were studied. Ten piglets were hyperventilated [arterial PCO2 (PaCO2) 15-20 Torr] with 100% O2 for 48 h and compared with 10 piglets treated with the identical management but given 0.7 mg/kg of dexamethasone at time 0 and every 12 h for the 48-h study. Six piglets were normally ventilated (PaCO2 40-45 Torr) for 48 h with 21% O2 as an additional control group. Pulmonary function and tracheal aspirates were examined at time 0 and every 24 h. Bronchoalveolar lavage was performed for surfactant analyses at the conclusion of the study. In animals treated with hyperoxia and hyperventilation, lung compliance decreased 32% and tracheal aspirate polymorphonuclear leukocyte (PMN) chemotactic activity increased by 51%, cell counts by 204%, number of PMNs by 277%, elastase activity by 111%, and albumin concentration by 328% over 48 h (P less than 0.05). In contrast, dexamethasone-treated piglets had increases in only tracheal aspirate albumin concentration (206%) over the 48-h study. All cellular and biochemical variables were lower in dexamethasone-treated compared with hyperoxic hyperventilated piglets. Room air normal ventilation controls had only a 108% increase in tracheal aspirate albumin concentration noted. Despite quantitative differences in surfactant among the three groups, activity was unaffected. Results indicate that hyperoxia and hyperventilation for 48 h causes significant inflammatory changes and acute lung injury and that prophylactic high-dose dexamethasone significantly ameliorates this lung damage.
authors.affiliation: Department of Pediatrics, Neonatology, Hematology-Oncology, University of Rochester School of Medicine and Dentistry, New York 14642.
authors.forename: J M
authors.initials: JM
authors.lastname: Davis
authors.forename: J
authors.initials: J
authors.lastname: Whitin
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001469:Barotrauma / Q000150:complications / Q000503:physiopathology; D003907:Dexamethasone / Q000378:metabolism / Q000494:pharmacology*; D006985:Hyperventilation / Q000150:complications / Q000503:physiopathology; D008168:Lung / Q000187:drug effects* / Q000503:physiopathology; D055370:Lung Injury; D016676:Macrophages, Alveolar / Q000187:drug effects / Q000473:pathology; D009504:Neutrophils / Q000187:drug effects / Q000473:pathology; D010100:Oxygen; D011663:Pulmonary Surfactants / Q000378:metabolism; D012121:Respiration, Artificial / Q000009:adverse effects; D013552:Swine
chemical_list: D011663:Pulmonary Surfactants; D003907:Dexamethasone; D010100:Oxygen