Prospective, randomized comparison of epidural versus parenteral opioid analgesia in thoracic trauma

Abstract

Objective: To evaluate systemic versus epidural opioid administration for analgesia in patients sustaining thoracic trauma.

Summary background data: The authors have previously shown that epidural analgesia significantly reduces the pain associated with significant chest wall injury. Recent studies report that epidural analgesia is associated with a lower catecholamine and cytokine response in patients undergoing elective thoracotomy compared with patient-controlled analgesia (PCA). This study compares the effect of epidural analgesia and PCA on pain relief, pulmonary function, cathechol release, and immune response in patients sustaining significant thoracic trauma.

Methods: Patients (ages 18 to 60 years) sustaining thoracic injury were prospectively randomized to receive epidural analgesia or PCA during an 18-month period. Levels of serum interleukin (IL)-1beta, IL-2, IL-6, IL-8, and tumor necrosis factor-alpha (TNF-alpha) were measured every 12 hours for 3 days by enzyme-linked immunosorbent assay. Urinary catecholamine levels were measured every 24 hours. Independent observers assessed pulmonary function using standard techniques and analgesia using a verbal rating score.

Results: Twenty-four patients of the 34 enrolled completed the study. Age, injury severity score, thoracic abbreviated injury score, and length of hospital stay did not differ between the two groups. There was no significant difference in plasma levels of IL-1beta, IL-2, IL-6, or TNF-alpha or urinary catecholamines between the two groups at any time point. Epidural analgesia was associated with significantly reduced plasma levels of IL-8 at days 2 and 3, verbal rating score of pain on days 1 and 3, and maximal inspiratory force and tidal volume on day 3 versus PCA.

Conclusions: Epidural analgesia significantly reduced pain with chest wall excursion compared with PCA. The route of analgesia did not affect the catecholamine response. However, serum levels of IL-8, a proinflammatory chemoattractant that has been implicated in acute lung injury, were significantly reduced in patients receiving epidural analgesia on days 2 and 3. This may have important clinical implications because lower levels of IL-8 may reduce infectious or inflammatory complications in the trauma patient. Also, tidal volume and maximal inspiratory force were improved with epidural analgesia by day 3. These results demonstrate that epidural analgesia is superior to PCA in providing analgesia, improving pulmonary function, and modifying the immune response in patients with severe chest injury.

Figures

Figure 1. Effect of route of opioid administration on patient verbal rating score with coughing. The epidural route was significantly (p

Figure 2. Maximal inspiratory force measurements increased for the patients receiving epidural analgesia throughout the study period. In contrast, the PCA group had a progressive decline in maximal inspiratory force (p

Figure 3. Tidal volume measurements increased in the epidural group and decreased in the PCA group throughout the study (p

Figure 4. Plasma levels of IL-1β, IL-2 and TNF-α were not altered by the route of analgesic administration.

Figure 5. Plasma levels of IL-6 were elevated at all time points. By days 2 and 3, the measurements were markedly lower in the epidural group. However, this was not statistically significant.

Figure 6. Epidural administration of opioid significantly lowered plasma levels of IL-8 throughout the study, reaching statistical significance on days 2 and 3 (p

Figure 7. There was no difference in the 24-hour urinary catecholamine metabolite concentration between the study groups.