Effect of TENS on pain, medications, and pulmonary function following coronary artery bypass graft surgery

The efficacy of transcutaneous electrical nerve stimulation (TENS) as an adjunct to narcotic medications for the management of postoperative pain was assessed in a prospective, randomized, controlled study of patients following coronary artery bypass graft (CABG) surgery with the right or left internal thoracic artery (ITA). Forty-five male patients (mean age, 57 +/- 6 years) were randomly assigned to (1) TENS, (2) placebo TENS, or (3) control treatments (n = 15 each), following extubation and during the 24- to 72-h postoperative period. Two-way analysis of variance tests indicated no significant differences among treatment groups for (1) pain with cough, (2) narcotic medication intake, (3) FVC, (4) FEV1, and (5) PEFR (p > 0.05). However, pain at rest reported by the TENS group was significantly lower than that reported by the control group (treatment main effect; p < 0.04), although no significant differences were observed between the TENS and placebo or between the placebo and control groups (p > 0.05). All six criterion measures were characterized by significant changes over time for the entire group (n = 45; time main effect; p < 0.01), as follows: pain and medication intake were similar on days 1 and 2, but were significantly less on day 3, and pulmonary functions were significantly lower than preoperatively on day 1, decreased further on day 2, and despite an improvement on day 3, remained significantly lower than preoperative values (p < 0.01). This study suggests that the addition of TENS, applied continuously during the immediate postoperative period following CABG with ITA, may not be advantageous in pain management or the prevention of pulmonary dysfunction.