Endotracheal naloxone in rabbits: No adverse effects on blood gases and lung tissue

52 Endotracheal Naloxone in Rabbits: No Adverse Effects on Blood Gases and Lung Tissue SC Rector, RW Geiss, K Beamer, P Legg/Emergency Service, and Departments of Surgery and Pathology, West Virginia School of Medicine, Morgantown We compared endotracheal naloxone with normal saline solution to study the effects on arterial blood gases and lung tissue in 16 rabbits. The pulmonary effects of endotracheal naloxone have not been studied previously. Eight rabbits received naloxone through an endotracheal tube, and eight controls received normal saline. Blood gases were sampled for 30 minutes. Four subject rabbits and four controls were killed after two days; the remaining rabbits were killed after six weeks. Microscopic analysis of lung tissue was done by a pathologist blinded to the identity of the specimens. There was no significant difference in blood gas values between the naloxone and control groups. By microscopy, there was no observed pattern of variance in pulmonary pathology between the subject and control groups. This experiment revealed no adverse effects on rabbit blood gases and lung tissue after one dose of endotracheal naloxone as compared with saline. Further study is needed before endotracheal naloxone can be considered safe for human use.