Comparison of two concentrations of bupivacaine by continuous paravertebral infusion after thoracotomy with pulmonary resection: a double-blind, randomized clinical trial

Resumen

Background and objectives: Post-thoracotomy pain management should be based on a multimodal approach that includes continuous regional analgesia. The objective of this study was to compare the analgesic efficacy of two concentrations of bupivacaine (0.2% and 0.3%) through a paravertebral catheter, both group plus fentanyl 2 mcg/ml. Methods: We conducted a randomized double-blind clinical trial to compare these two concentrations in patients undergoing pulmonary resection by thoracotomy in Donostia University Hospital between November 2010 and May 2011 (n=59). The paravertebral catheter was placed prior to the surgical intervention, with the patient awake and sitting upright. Data were analyzed on an intention-to-treat basis. The Chi-squared test was used for qualitative variables and Student's t-tests or Mann-Whitney-Wilcoxon tests for quantitative variables, depending on the distribution of the variables. Statistical analysis was performed using IBM SPSS software (Version 17). Results: We did not find statistically significant differences in postoperative pulmonary function (p=0.49), self-perceived pain (VAS; p=0.28) or cumulative morphine consumption (p=0.101) in the two groups. We observed adverse effects in 8 patients in group 1 (29.6%) and in 12 patients (37.5%) in group 2, the difference not being statistically significant (p=0.52). Conclusions: Continuous thoracic paravertebral block for 48 hours is a good technique for the management of postoperative pain after pulmonary resection by thoracotomy. With moderate doses of local anesthetics (bupivacaine 0.20%) we achieved good pain control and observed few systemic complications than major doses (bupivacaine 0.30 %)