[Drug-related copmlicatios of epidural postoperative analgesia]

Postoperative epidural analgesia may be associated with a range of complications. The aim of the study was to register and analyze drug-related complications that occurred in patients having epidural analgesia.

One thousand, three hundred patients received continuous epidural analgesia after major thoracic, vascular or urologic operations, and were cared for by the Acute Pain Service for 3.5 +/- 1.7 days. They were visited and assessed every 7 hours.

Drug-related side effects and complications were noted in 58% of patients. Moderate hypotension (SAP < 100 mmHg or decrease by 20% of the initial blood pressure) occurred in 46% of patients, and severe hypotension (SAP < 90 mmHg or decrease by 30% of the initial blood pressure) occurred in 7% of patients). Pruritus occurred in 3.0% of patients, nausea and vomiting in 1.1%, and extensive sedation (Ramsey score >4) in 0.2%. Two patients received an epidural infusion intravenously. Side effects were related to the dose of bupivacaine, the time of treatment, or the method of drug administration (bolus vs. continuous). Nausea and vomiting were strongly correlated to the hypotension.

A surprisingly high percentage of side effects and complications were observed during epidural analgesia, indicating the necessity for careful monitoring of anaesthetized patients. Since bolus administration of bupivacaine to the epidural space is associated with marked hypotension, continuous infusion should be considered as the method of choice.