Propofol patient-controlled sedation during hip or knee arthroplasty in elderly patients

Purpose: Little information is available regarding the use of patient-controlled sedation (PCS) among the elderly. This: study evaluated the safety and efficacy of propofol PCS among elderly patients undergoing hip or knee arthroplasty. Methods: Forty patients, aged 65-78 yr, undergoing hip or knee arthroplasty under regional anaesthesia were randomized to receive propofol PCS (dose = 0.3 mg.kg(-1), delay = three min; n = 20) or anaesthetist-administered midazolam-fentanyl sedation (n = 20). Sedation, anxiety and discomfort visual analogue scores (VAS) were measured, by an independent observer, preoperatively, immediately at the end of surgery and one hour,following admission to the postanaesthetic care unit (PACU). Cognition was evaluated, using an abbreviated Mini Mental Status Examination, preoperatively and in the PACU. Patient satisfaction, based on VAS and a brief questionnaire, was measured in the PACU. The incidence of intraoperative complications was also compared. Results: Patient satisfaction was high in each group. Sedation and anxiety VAS were similar in each group, A high incidence of pain with drug injection was noted among patients receiving propofol (80%). Transient deeper levels of sedation (6 vs 1; P = 0.05) were observed more commonly in the propofol PCS group. Conclusion: Propofol PCS provides effective sedation. Using a propofol dose of 0.3 mg.kg(-1), transient episodes of deeper sedation were noted more frequently among patients receiving PCS. These episodes did not require intervention but, suggest that this propofol PCS dose approaches the limit of safety and Should be further reduced for some elderly patients.