Control of Acute Postoperative Pain by Transcutaneous Electrical Nerve Stimulation after Open Cardiac Operations: A Randomized Placebo-Controlled Prospective Study

Abstract

We investigated the effectiveness of transcutaneous electrical nerve stimulation (TENS) therapy on pain during the first 24 hours after a cardiac surgical procedure. A total of 60 patients who had undergone median sternotomy (MS) for coronary artery bypass graft (n = 55) or valve repair surgery (n = 5) were randomized to receive TENS and pharmacologic analgesia, placebo TENS and pharmacologic analgesia, or pharmacologic analgesia alone (control group). For each group we recorded severity of pain, analgesic intake, and pulmonary complications. Pethidine HCL and metamizol sodium were administered for postsurgical analgesia. Pain after MS was measured on a 10-point visual analogue scale (VAS). Mean scores in the TENS, placebo TENS, and control groups, respectively, were 5.70 +/- 1.78, 5.75 +/- 1.83, and 5.95 +/- 1.63 before treatment (P >.05); 2.40 +/- 1.18, 3.90 +/- 1.48, and 3.55 +/- 1.60 on the 12th hour of the intervention (P < .05); and 1.25 +/- 0.91, 2.30 +/- 1.34, and 2.15 +/- 1.13 on the 24th hour of the intervention (P < .05). The mean VAS scores decreased within each group (P < .05). However, the mean VAS scores decreased much more significantly in the TENS group (P < .05). Metamizol sodium intake was 1.05 +/- 0.39 g, 2.30 +/- 1.08 g, and 2.90 +/- 1.20 g and pethidine HCL intake was 17 +/- 16.25 mg, 57 +/- 21.54 mg, and 51.50 +/- 18.99 mg, respectively, in the TENS, placebo TENS, and control groups. Metamizol sodium and pethidine HCL intake was least in the TENS group (P < .05). Postoperative complications were observed in 6 (10%) of patients. The most frequent complication was atelectasia. TENS was more effective than placebo TENS or control treatments in decreasing pain and limiting opioid and nonopioid medication intake during the first 24-hour period following MS.