An evaluation of tests of psychomotor function in assessing recovery following a brief anaesthetic

Abstract

This study was designed to evaluate the usefulness of three commonly used tests of psychomotor function and one test of short-term memory in assessing recovery from a brief nitrous oxide, oxygen and halothane anaesthetic. Twenty-six female patients undergoing minor gynaecological surgery were allocated to one of three treatment groups depending on premedication (placebo, low dose and high dose). Immediate recovery was most rapid in the placebo group. Both the tests of simple reaction time and picture recall were able to differentiate between the post-anaesthetic recovery of the high-dose group and that of the other two groups. Neither component of the letter cancellation test showed a clear difference in recovery pattern. Tests of critical flicker fusion were too unreliable to be of use in clinical decision making. Our results suggest that tests of reaction time and memory were more sensitive than letter cancellation in assessing recovery.