Comparison between patient-controlled analgesia and subcutaneous morphine in elderly patients after total hip replacement

Background. The goal of this study was to evaluate the effectivenesson postoperative pain, and cognitive impact, of patient-controlledanalgesia (PCA) compared with subcutaneous (s.c.) injectionsof morphine in elderly patients undergoing total hip replacement(THR). Methods. Forty patients older than 70 yr were randomly assignedto two different postoperative analgesic techniques for 48 h:i.v. PCA morphine (dose, 1 mg; lockout interval, 8 min; PCAgroup) or regular s.c. morphine injections (SC group). Postoperativepain was assessed at rest and when moving, using a visual analoguescale (VAS) every 4 h. A Mini Mental Status (MMS) examinationwas used to assess cognitive functions before surgery, at 2h, 24 h and 48 h after surgery, and at hospital discharge. Side-effectswere also recorded systematically during the first 48 h aftersurgery. Results. The PCA group showed significantly lower pain scoresthan the SC group both at rest and during mobilization. However,the clinical significance of pain scores was weak. There wasno intergroup difference in postoperative MMS scores. The incidenceof side-effects was similar in both groups. Conclusions. We conclude that in healthy elderly subjects undergoingTHR, the flexibility of the analgesic regimen is more importantthan the route of administration with regard to efficacy, adverseeffects and recovery of cognitive function. Br J Anaesth 2003; 90: 53–7