Effect of low concentrations of halothane on the oxygen electrode

The effect of low concentrations of halothane dissolved in saline (equivalent to 0.34% halothane) on the oxygen electrode was examined using a multi-wire Clark type electrode, consisting of eight platinum wires, each of 15 microns tip diameter. On the first exposure of the day to saline equilibrated with halothane in 10% oxygen or air, the output of the oxygen electrode increased by 40% over 56 min. On the second and subsequent exposures the increase in output was much less, but was still 10% greater than the correct values. After immersing the electrode overnight in saline without halothane the high sensitivity to halothane was present again next morning, even if neither membrane nor electrolyte was changed.