Comparison between Thoracic Epidural Block and Thoracic Paravertebral Block for Post Thoracotomy Pain Relief.

INTRODUCTION: Postoperative pain after thoracotomy is being considered one of the most severe pain and if not treated well, can result in various respiratory and other complications.

AIM: Present study was conducted with the aim to compare continuous thoracic epidural infusion with continuous paravertebral infusion for postoperative pain using Visual Analogue Scale (VAS) score and four point observer ranking. The secondary outcomes measured were pulmonary functions and any complication like hypotension, bradycardia, nausea, vomiting, urinary retention and neurological complications if any.

MATERIALS AND METHODS: Sixty patients of age group 18-60 years posted for anterolateral thoracotomy surgery for lung resection were randomised either to epidural or paravertebral group in this randomised prospective double blind study. In Epidural group 7.5ml bolus of 0.125% Bupivacaine with 50μg Fentanyl and in Paravertebral group 15ml bolus of 0.125% Bupivacaine with 50μg Fentanyl was given 30 minutes before the anticipated end of surgery. Bolus dose was followed by infusion of 0.125% Bupivacaine with 2μg/ml Fentanyl at the rate of 5 ml/hr in both groups. Parameters noted were Mean Arterial Pressure (MAP), Heart Rate (HR), Oxygen Saturation (SpO2 ), Arterial Blood Gas (PaCO2 , P/F ratio), Visual Analogue Scale (VAS) and Four Point Observer Ranking Scale (FPORS) for pain, number of sensory segments blocked (by checking for pinprick sensation), requirement of infusion top ups and rescue analgesia (Tramadol), pre and postoperative pulmonary function test {(Forced Expiratory Volume (FEV)1 , Forced Vital Capacity (FVC), FEV1 /FVC, Peak Expiratory Flow Rate (PEFR)} and complications from start of infusion till 24 hours in the postoperative period.

RESULTS: Both the techniques were effective in relieving pain but pain relief was significantly better with epidural. Postoperatively, HR, SpO2 , P/F ratio and PaCO2 were comparable between group E and P. There was significant decline in FeV1 , FVC, FeV1 /FVC and PEFR in postoperative period as compared to preoperative value in both the groups. Hypotension and bradycardia were more in group E.

CONCLUSION: Both the techniques, continuous thoracic epidural block and continuous thoracic paravertebral block were effective for post-thoracotomy pain relief; however, epidural block provides better pain relief. The incidence of sympatholytic complications was more in epidural group. The effect on respiratory mechanics was equivalent. Hence, paravertebral block can be used in post thoracotomy pain relief in those patients where thoracic epidural is contraindicated.