[Postoperative peridural analgesia. Continuous versus patient-controlled administration of a low-dose mixture of sufentanil, clonidine and bupivacaine].

UNLABELLED: The purpose of our study was to find out whether patient-controlled epidural administration (PCEA) of a mixture containing a low-dose local anaesthetic, opioid and alpha 2-agonist provides as good or better postoperative analgesia as continuous epidural administration of the same analgetic solution.

METHODS: 30 patients (ASA I-III), scheduled for major abdominal surgery, were randomly divided into 2 groups. 90 minutes after induction of general anaesthesia all patients received a continuous epidural infusion of 5 ml/h of the analgetic solution (50 micrograms sufentanil + 150 micrograms clonidine in 50 ml 0.125% bupivacaine) until the end of surgery. Immediately postoperatively the patients of group A received a continuous infusion of the study solution (5-8 ml/h), the patients of group B received a baseline continuous epidural infusion (3 ml/h), additionally they could self-administer 5 ml boli via a PCEA device. Measurements included the total dose of infused drug solution, pain at rest and on exercise by a visual analogue scale, cardiorespiratory data and side effects within the first 24 hours postoperatively. A standardised interview on analgesia and side effects was held 2 days after surgery.

RESULTS: The PCEA group demanded less epidural analgesics (gr. B: 112 +/- 33 ml vs. gr. A: 135 +/- 20 ml) p < 0.01). Both continuous epidural infusion and patient-controlled administration provided very good analgesia at rest (gr. A: VAS 0.4 +/- 0.4 and gr. B: VAS 0.4 +/- 0.5) (n.s.). On exercise continuous epidural infusion of analgesics resulted in significantly lower pain scores (gr. A: 1.9 +/- 1.1) than patient-controlled application (gr. B: 3.4 +/- 1.1) (p < 0.01). We did not notice severe side effects such as respiratory depression or drop of heart rate or blood pressure.

CONCLUSION: In patients at rest both continuous and patient-controlled epidural administration of analgesics provides excellent analgesia after major abdominal surgery. Contrariwise, patients on exercise who could use a PCA-device experienced more pain compared to those with a continuous epidural infusion technique. On the other hand the patients of the PCA-group consumed less epidural analgesics. We did not notice any severe side effects such as respiratory depression or cardiovascular instability during the study.