SUBARACHNOID AND INTRAVENOUS PCA VERSUS BOLUS ADMINISTRATION FOR POSTOPERATIVE PAIN RELIEF IN ORTHOPEDIC PATIENTS

Background: Patient-controlled analgesia (PCA) with intravenous piritr amide and subarachnoid bupivacaine was studied during postoperative pa in management in comparison with nurse-administered bolus injections. Methods: Following general anaesthesia (n=60) patients randomly receiv ed either 3.75-7.5 mg i.v. piritramide on demand (group P-Bolus) or vi a 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 con tinuous spinal anaesthesia (n=60; CSA; 28-G spinal catheter) patients randomly received a subarachnoid injection of 1.5 mi bupivacaine 0.25% every 2-4 h (group B-Bolus) or a baseline infusion of 0.5 ml/h bupiva caine 0.125% plus 0.5 mi bupivacaine 0.125% on demand via PCA (group B -PCA; lockout time: 30 min). Pain ratings were assessed hourly by pati ents using a visual analogue scale (0=no pain, 100 mm=unbearable pain) . Statistics: multivariate analysis of variance. Results: While pain s cores did not differ between group P-Bolus and P-PCA, group B-PCA show ed the lowest pain ratings (18+/-22 mm) differing significantly from g roup B-Bolus (41+/-32 mm; P<0.001). Group P-PCA required more piritram ide than group P-Bolus (46+/-15 mg vs. 32+/-13 mg, P=0.001). In contra st 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 tha n nurse-administered bolus-administration of bupivacaine, while the pr esent study failed to show superiority of i.v. PCA over i.v. bolus-adm inistration of piritramide. PCA using the subarachnoid route is a prom ising concept for treatment of postoperative pain in orthopaedic patie nts, while the PCA piritramide regime of this study warrants improveme nt.