Patient-controlled analgesia (PCA) with intravenous piritramide and subarachnoid bupivacaine was studied during postoperative pain management in comparison with nurse-administered bolus injections.Methods:
Following general anaesthesia (n=60) patients randomly received either 3.75-7.5 mg i.v. piritramide on demand (group P-Bolus) or via PCA (group P-PCA; initial bolus: 3.75 mg i.v. piritramide, baseline rate: 1 mg/h, demand-dose 1.5 mg, lockout time: 20 min). Following continuous spinal anaesthesia (n=60; CSA; 28-G spinal catheter) patients randomly received a subarachnoid injection of 1.5 ml bupivacaine 0.25% every 2-4 h (group B-Bolus) or a baseline infusion of 0.5 ml/h bupivacaine 0.125% plus 0.5 ml bupivacaine 0.125% on demand via PCA (group B-PCA; lockout time: 30 min). Pain ratings were assessed hourly by patients using a visual analogue scale (0=no pain, 100 mm=unbearable pain). Statistics: multivariate analysis of variance.Results:
While pain scores did not differ between group P-Bolus and P-PCA, group B-PCA showed the lowest pain ratings (18±22 mm) differing significantly from group B-Bolus (41±32 mm; P<0.001). Group P-PCA required more piritramide than group P-Bolus (46±15 mg vs. 31±13 mg, P=0.001). In contrast group B-PCA required less bupivacaine than group B-Bolus (18±4 vs. 23±7 mg, P=0.002).Conclusion:
PCA with CSA was more effective than nurse-administered bolus-administration of bupivacaine, while the present study failed to show superiority of i.v. PCA over i.v. bolus-administration of piritramide. PCA using the subarachnoid route is a promising concept for treatment of postoperative pain in orthopaedic patients, while the PCA piritramide regime of this study warrants improvement.