Patient-controlled Sedation Versus Target-controlled Infusion in Orthopaedic Surgery Under Central Neuraxial Block

Central neuraxial block (CNB) is one of the mainstays of anaesthesia methods in various disciplines particularly orthopaedic surgeries. However the state of consciousness can potentially cause patient anxiety thus sedation is often utilized as a mean to improve patient satisfaction and increase patient acceptance of CNB.

Conventionally, the anaesthesiologist administers sedatives for the patients. Propofol is the commonly used drug for sedation due to its favourable pharmacokinetic profile, which results in fast induction, easy control of depth of sedation and rapid recovery. It can be infused by using target-controlled infusion (TCI) devices where the anaesthetists titrates propofol by setting desired target plasma and effect site concentration. However it is difficult to judge precisely patient requirements for adequate patient sedation, comfort and analgesia as patients' needs differ.

Patient-controlled sedation (PCS) is a valid option, initially adapted from post surgery patient-controlled analgesia. It allows patients to titrate sedative medication to their comfort and therefore present an option that addresses the needs of patients with strong desire to maintain sense of control during procedures.

This study was designed to compare total propofol requirement between PCS versus TCI sedation (TCIS), complications and patient satisfaction, in patients undergoing lower limb orthopaedic surgery under CNB.