O-029CONTROL OF POST-THORACOTOMY PAIN BY TRANSCUTANEOUS ELECTRICAL NERVE STIMULATION: A RANDOMIZED PROSPECTIVE STUDY

Abstract

Objectives: Transcutaneous electrical nerve stimulation (TENS) has been used successfully to control postoperative pain in different surgical procedures. We aim to assess the efficacy of TENS on post-thoracotomy pain. Methods: Prospective study of 60 patients submitted to thoracotomy. Patients were divided in two independent groups [anterior thoracotomy (AT) and posterolateral thoracotomy (PT)]. Postoperative analgesia protocol consisted in local anaesthetic (300 mg/day) through a paravertebral catheter placed by the surgeon at the end of the procedure and metamizole sodium (every 6 h). Subcutaneous meperidine hydrochloride was employed as a rescue drug. Patients were randomized in 2 groups: TENS group (30 patients) who received postoperatively TENS for 3 days and control group (30 patients) without TENS. The level of pain was measured with the visual analogic scale (VAS) at 1, 6, 24, 48 and 72 h after surgery. Results: Seven patients (11.6%) needed meperidine as rescue drug (2 with TENS and 5 in control group). Mean VAS values were the following: all the cases (n = 60): 5.0 + 1.9, AT (n = 36): 4.3 + 2.0, PT (n = 24): 5.8 + 1.9, TENS (n = 30): 4.6 + 2.0, control group (n = 30): 5.6 + 2.1, ATwith TENS (n = 18): 4.0 + 2.1, AT in control group (n = 18): 4.8 + 1.9, PTwith TENS (n = 12): 5.5 +1.9, PT in control group (n = 12): 6.1 + 1.7. Conclusions: Post-thoracotomy analgesia combining paravertebral catheter and a non-steroidal anti-inflammatory drug is a safe and effective practice. Patients submitted to ATexperienced less pain than those with PT (4.3 vs 5.8, P < 0.01). VAS score in the TENS group was significantly lower than in the control group 1, 6, 24, 48 and 72 h postoperatively. Finally, TENS patients required less rescue analgesia compared to control group (P < 0.05). TENS is a valuable complementary strategy to alleviate post-thoracotomy pain.