A Randomized Double-Blinded Study of Clonidine as an Analgesic Adjuvant to Continuous Extrapleural Intercostal Bupivacaine for Post-Thoracotomy Pain

We prospectively evaluated the effect of adding clonidine to bupivacaine for continuous intercostal nerve block in terms of VAS scores and pulmonary function tests. Thirty patients scheduled to undergo thoracotomy were randomized to receive either 2mg/kg of 0.125% bupivacaine alone or 2mg/kg of 0.125% bupivacaine with 2µg/kg clonidine as an infusion through an extrapleural intercostal catheter. Hemodynamic parameters, VAS scores and pulmonary function tests (FEV1, FVC, and PEFR) were recorded by a blinded observer. Patients in the clonidine group had better VAS scores, but a higher incidence of hypotension and sedation. There was no significant difference in pulmonary function between the groups. We conclude that using clonidine as an adjunct to bupivacaine for continuous intercostal nerve block improves pain relief after thoracotomy, but hypotension was seen to be a major adverse effect interfering with clinical application.