ALTERATIONS IN THE COURSE OF ACID-INDUCED LUNG INJURY IN RATS AFTER GENERAL-ANESTHESIA - VOLATILE ANESTHETICS VERSUS KETAMINE

Pulmonary aspiration of gastric acid is a complication that occurs dur ing anesthesia. The effects of the often used anesthetics on the infla mmatory response after aspiration of acid are not known. We examined t he effects of three different inhaled anesthetics-halothane, enflurane , and isoflurane-as well as parenteral ketamine, on the associated imm ediate mortality, alveolar protein leakage, and morphometric changes a fter intrapulmonary instillation of acidic solution in rats. Animals i n a deep state of anesthesia had a higher mortality after the instilla tion of acidic solutions than those in lighter stages (82.5% vs 31.6%) . Protein leakage over 5 h was greater in the animals receiving volati le anesthetics (range 0.9-1.2) compared with those receiving ketamine (0.6 +/- 0.05). Desferoxamine did not decrease protein leakage in acid -injured animals (1.1 +/- 0.06 vs 1.02 +/- 0.08). Furthermore, volatil e anesthetics resulted in an increase in the acute inflammatory respon se and leukocytic infiltration compared with ketamine in acid-injured lungs. We conclude that the administration of inhaled anesthetics was associated with exacerbation of an acute inflammatory response after a spiration of acidic solution. Lung injury was not increased with ketam ine anesthesia. This difference was the result of the hypotensive effe cts of inhaled anesthetics. Implications: This study reveals that the use of inhaled anesthetics aggravates inflammation secondary to gastri c aspiration and should be avoided on diagnosis of the situation.