Sister chromatid exchange in human lymphocytes exposed to isoflurane and nitrous oxide in vitro

The question of whether or nor inhalation anaesthetics are genotoxic remain s controversial. Therefore, we have studied the in vitro genotoxic potentia l of isoflurane and nitrous oxide in human lymphocytes. Blood samples were obtained from eight healthy male, non-smelting volunteers, which were incub ated and exposed to increasing concentrations of isoflurane (0.0, 0.3, 0.6 and 1.2 mmol litre(-1)) or 50% nitrous oxide in oxygen. Baseline sister chr omatid exchange (SCE) rate per cell was mean 7.65 (SD 1.5) which increased to 9.15 (1.0), 9.55 (1.4) and 9.95 (1.8) SCE/cell during exposure to isoflu rane 0.3, 0.6 and 1.2 mmol litre(-1), respectively. During 50% nitrous oxid e exposure, SCE rate was 9.26 (1.4). The difference between the control and exposed cells was statistically significant (P less than or equal to 0.05) . We conclude that exposure to nitrous oxide and subanaesthetic concentrati ons of isoflurane can produce genetic damage in peripheral lymphocytes in v itro.