Efficacy of preemptive, continuous, thoracic paravertebral nerves block with ropivacaine 0.5% in relieving post-thoracotomy pain

ABSTRACT

The purpose of our study was to evaluate the efficacy of preemptive, continuous paravertebral block to relief post-thoracotomy pain after open heart surgery. to help weaning from mechanical ventilation. Also, to study its effect on pulmonary function tests postoperatively, and any complication that occurs. Patients were classified into two groups, 20 patients each In the paravertebral group, 20 patients with paravertebral catheter inserted at the 4th thoracic space before induction of anesthesia. Postoperative pain relief was achieved by preemptive injection of 20 ml of 0.5% ropivacaine through the paravertebral catheter, followed by continuous infusion at a rate of 0.1 ml /kg/ hr of ropivacaine 0.5% during the perioperative period and 5 days postoperatively. In the control group, 20 patients were the postoperative analgesia was achieved by IM injection of 5 mg morphine 6 hrs starting at the end of the surgery and for 5 days postoperatively. In both groups, 20 mg pethidine was injected IV. if pain scoring was 3. postoperative data collected time to extuhatlon when criteria for extubation were fulfilled. pain score [VAS] at rest, on coughing, respiratory rate. FVC. PEFR/6 hrs for 48 hours postoperatively, total dose of pethidine used and any untoward effects. Both groups were comparable as regard age, duration of CPB and duration of surgery, but the time from admission to ICU till extubation was significantly shorter in the paravertebral group than in the control group [4.8 +/- 3.3 hours vs 6.3 +/- 4.5 hours]. The visual analogue pain scores were significantly lower in both groups at all time of measurements compared to full recovery score both at rest and on coughing. The paravertebral group has significant lower VAS pain score when compared to the control group at all time of measurements. The pethidine consumption was significantly less in the paruvertehrul group throughout all the study period. The respiratory rate decrease insignificantly in paravertebral group compared to preoperative value. In contrast, the decrease in respiratory rate was significant in the control group. There was significant difference between groups with lower rate in the control group at 12 hours till 36 hours postoperatively. The FVC and PEFR decreased significantly at recovery when compared with the preoperative value in both groups and then gradually increased during the 48 hours postoperatively. After recovery which was comparble in both groups, both had significantly lower values in the control group compared to the paravertebral group. Oxmietre recordings were significantly better in the paravertebral group throughout the 5 days study period compared with the control group. After full recovery, no patient in either group had a sedation score >2 throughout the study time, although patients in the control group were significantly more sedated till the 4th day postoperatively than in the paravertebral group. Nausea and vomiting occurred more frequently in the control group [8/5 vs 2/2] [P< 0.05]. Hypotension, after weaning from inotropes occurred only in 2 patients in the control group [P> 0.05]. Urinary retention after removal of urinary catheter occurred more frequently in the control group [11 vs 2] [P<0.001].There was no difference between group in the duration of ICU stay [3.9 vs 3.1 days]. We concluded that continuous paravertebral block, beginning before operation was highly effective for post-thoracotomy pain. In this study, we found that paravertebral analgesia was superior in terms of analgesia, pulmonary function and side effects then IM morphine