Patient-controlled sedation using inhaled anaesthetics provides several potential advantages. In a study of healthy volunteers, low-dose inhaled sevoflurane impaired volunteers' ability to complete a button-press task without significant cardiorespiratory compromise. Thus patient-controlled sedation using sevoflurane might be feasible; however, regulatory hurdles require proof of safety and efficacy through clinical trials. Although a promising concept, it must be demonstrated that patients cannot induce unconsciousness on their own despite any interactions with opioid analgesics. Significant steps remain before practical, patient-controlled sevoflurane sedation can be implemented.