Lee SY, et al. - Experts sought to determine the concentration (Ce) of remifentanil for preventing emergence cough following extubation in male and female elderly patients and evaluated the sex-related difference. Compared to male elderly patients, the remifentanil requirement for preventing emergence cough was lower in the female. This finding indicated sex-related differences in Ce of remifentanil. When using remifentanil target-controlled infusion for preventing emergence cough in elderly patients, sex ought to be considered.