Alveolar integrity and ultrastructure in pigs remain undamaged after exposure to sevoflurane

Previous studies have shown that both halothane and isoflurane have adverse but reversible effects on alveolar physiology. The present study was designed to test the hypothesis that also sevoflurane may affect alveolar integrity. Fifteen pigs were randomly selected to receive either thiopentone infusion (control group, n=8) or sevoflurane (n=7) at 4.0% inspiratory concentration (1.5 MAC) in air for 6 h. Tissue samples from the lungs were obtained at the end of the experiment. Both histopathological light microscopy and electron microscopy were used to assess the structural integrity of the alveoli. Pulmonary hemodynamics were comparable in both groups. Light microscopy showed no difference between the groups in the amount of alveolar macrophages, red blood cells or edema. Electron microscopy showed minor changes such as moderate local swelling of alveolar epithelium in both study groups. Alveolar type II cells were ultrastructurally unaltered in both study groups. We conclude that long-term, high concentration exposure to sevoflurane has no detrimental effect on the alveolar integrity in pigs.