Patient-controlled versus continuous anesthesiologist-controlled sedation using propofol during regional anesthesia in orthopedic procedures – a pilot study

Abstract

Objective: In the present study, we compared patient-controlled (PCS) and anesthesiologist-controlled sedation (ACS) with respect to adverse effects and patient centered outcomes. Methods: A total of 100 patients undergoing elective knee- or hip-replacement under spinal anesthesia were randomly allocated to either a PCS (bolus: 0.25 mg kg-1; no lockout interval; n = 50) or a continuous infusion of propofol 1% (3 mg kg-1 h-1; n = 50), following an initial bolus of 0.25 mg kg-1. Safety parameters and patient satisfaction were evaluated and calculated propofol plasma concentrations were analyzed. Results: Baseline characteristics were comparable between the groups. Patient satisfaction did not differ between the investigated groups. Memory of the operation was more pronounced in the PCS group. Mean propofol plasma levels were significantly higher in the ACS group and the individual variation was more pronounced in the PCS group. Episodes of respiratory depression occurred in one PCS and in three ACS patients. Conclusions: PCS using propofol boluses of 0.25 mg kg-1, without a lockout interval, appeared to be safe for sedation during knee- and hip replacements, with a high degree of patient satisfaction. PCS and ACS provided comparable satisfaction levels but PCS was associated with lower mean calculated plasma concentrations. Individual propofol consumption and associated plasma levels to obtain satisfactory levels of sedation are highly variable.