Clinical and bacteriologic survey of epidural analgesia in patients in the intensive care unit.

Abstract

The risk of bacterial contamination related to epidural analgesia in patients cared for in the intensive care unit has not been assessed. Thus the authors studied patients who received care in the intensive care unit who were given epidural analgesia for more than 48 h to determine the rates of local, epidural catheter, and spinal space infection and to identify risk factors. Each patient receiving epidural analgesia for longer than 48 h was examined daily for local and general signs of infection. A swab sample for culture was taken if there was local discharge; all epidural catheters were cultured on withdrawal. All patients underwent weekly neurologic monitoring for 1 month; those with positive epidural catheter cultures had one spinal magnetic resonance image scan. The 75 patients cared for in the intensive care unit who were studied had been receiving epidural analgesia for a median of 4 days (interquartile range, 3.5 to 5 days). Twenty-seven patients had signs of local inflammation (erythema or local discharge), and nine of these had infections. All the patients who had both local signs also had infection. All nine infections were local (12%), but four patients also had epidural catheter infections (5.3%). No patient with erythema alone or without local signs had a positive epidural catheter culture. No spinal space infection was diagnosed. Staphylococcus epidermidis was the most frequently cultured microorganism. Local infection was treated by removing the epidural catheter without any antibiotics. Concomitant infection at other sites (21 of 75 patients, or 28%), antibiotic therapy (64 of 75 patients, or 85%), the duration of epidural analgesia, and the insertion site level of the epidural catheter were not identified as risk factors for epidural analgesia-related infections. The risk of epidural analgesia-related infection in patients in the intensive care unit seems to be low. The presence of two local signs of inflammation is a strong predictor of local and epidural catheter infection.