Transcutaneous electrical nerve stimulation for post-sternotomy pain

Abstract

Background: Post-sternotomy patients report high pain levels, possibly leading to the development of pulmonary complications, decreased shoulder range of motion (ROM) and Chronic Post-Sternotomy Pain (CPSP). Transcutaneous Electrical Nerve Stimulation (TENS) is a non-invasive application of low-voltage current which provides pain relief and has been reported to reduce pain and improve functionality. Objectives: To investigate the effect of using TENS in the acute post-operative phase on pain, lung function, shoulder flexion, and C-Reactive Protein (CRP) levels and the prevalence of CPSP in patients who undergo a sternotomy procedure. Study Design: Randomized placebo-controlled pre-test – post - test design. Methods: Phase 1 - 81 post-sternotomy patients were randomly assigned to 3 groups: TENS (n = 28), placebo-TENS (n = 26), control (n = 27), all receiving standard routine care. TENS and placebo-TENS were applied for 50 minutes, 5 hours after administration of prescribed medication and repeated daily for 4 days. Outcome measures: NRS-11 for pain, Universal inclinometer for ROM, Spirometer for forced vital capacity (FVC) and expiratory volume (FEV1), blood test for CRP. Phase 2 - 69 patients were assessed after 3 months. Results: Phase 1 - TENS significantly reduced pain at rest, on coughing and on shoulder flexion (p < .001) and significantly improved lung function (p < .05). Placebo-TENS significantly reduced pain (p < .05), but with a smaller pain difference than TENS. CRP levels were not statistically significant between groups (p = .944). TENS significantly improved shoulder ROM (p < .001). Phase 2 – No statistical significance was noted in pain (p = .276), lung function (p > .05) and shoulder ROM (p > .05). Conclusion: TENS significantly reduces pain and improves lung function and shoulder ROM from days 1 – 4 post-operatively but does not affect CPSP in post-sternotomy patients.