Comparison of short-term versus long-term epidural analgesia after limited thoracotomy with special reference to pain score, pulmonary function, and respiratory muscle strength.

To determine the optimal duration of epidural analgesia (EA) after lung cancer surgery, a retrospective analysis was conducted to compare chest pain, pulmonary function, and respiratory muscle strength between patients given EA until postoperative day (POD) 3 and those given EA until POD 8. Each group comprised 25 lung cancer patients who underwent a lobectomy under anterior limited thoracotomy and given continuous thoracic EA using morphine until POD 3 (POD3-EA group) or POD 8 (POD8-EA group). The two groups were matched by sex and age. Postoperative pain from PODs 1 to 12 was evaluated by the pain score and analgesic requirements. The pulmonary function and respiratory muscle strength were measured on POD 7. The POD3-EA group did not experience any increase in pain after withdrawal, but the POD8-EA group did show a significant increase in pain the day after withdrawal (P < 0.05). The pain scores on PODs 8 and 9 in the POD8-EA group were significantly higher than those in the POD3-EA group (P < 0.05). There was no significant difference in pulmonary function and respiratory muscle strength on POD 7 between the two groups. Although the postoperative thoracic EA did not affect pulmonary function and respiratory muscle strength, prolonged thoracic EA after a limited thoracotomy significantly increased the pain after withdrawal, thus negatively affecting postoperative pain control.