[Correlation of acute pain treatment to occurrence of chronic pain in tumor patients after thoracotomy]

Abstract

Background & objective: Some researches found that the intensity, property and management of acute pain are associated with chronic pain in tumor patients after thoracotomy. Chronic pain may be transformed from acute pain. However, there are no routine or standard strategies to effectively prevent or relieve chronic pain in tumor patients after thoracotomy. This study was to explore the correlation of acute and chronic pain in tumor patients after thoracotomy.

Methods: A total of 105 patients (American Society of Anesthesiologists physical status I-II) underwent thoracotomy were randomly divided into 3 groups: 36 received administration of ropivacaine and morphine through thoracic epidural preoperatively (group PE), 36 received the same treatment postoperatively (group E), and 33 received intravenous infusion of fentanyl postoperatively (group IV). VAS scores were recorded in the first 48 h after operation. The occurrence of chronic pain was observed at the first, second, third, sixth months after operation.

Results: VAS scores in the first 48h after operation were significantly lower in group PE and group E than that in group IV (P<0.05). VAS scores were significantly lower in group PE than in group E (P=0.004 at 4 h, P=0.013 at 8 h, P=0.035 at 24 h). The occurrence rate of pain after operation was significantly lower in group PE than in groups E and IV in the first and second months (Chi2=5.989, P=0.014; Chi2=7.603, P=0.006), and lower in groups PE and E than in group IV in the third and sixth months (Chi2=6.585, P=0.010; Chi2=8.661, P=0.003). The duration of pain was significantly shorter in group PE than in groups E and IV (P=0.027, P=0.009).

Conclusions: Chronic pain after thoracotomy is associated with the intensity and management of acute pain after thoracotomy. The patients with intensive acute pain would experience intensive and long-term chronic pain. Preemptive administration with thoracic epidural ropivacaine and morphine can decrease the incidence and duration of chronic pain after operation.