Effects of transcutaneous electrical nerve stimulation on pain, pulmonary function, and respiratory muscle strength after posterolateral thoracotomy: a randomized controlled trial

Abstract

Purpose To evaluate the efects of transcutaneous electrical nerve stimulation (TENS) compared to placebo TENS and a control group on pain, pulmonary function, respiratory muscle strength, and analgesic medications in the postoperative period of thoracotomy in an Intensive care unit (ICU). Methods Patients who had undergone posterolateral thoracotomy were randomly allocated to receive TENS during ICU stay, or placebo TENS, or into the control group. All groups received conventional physiotherapy. We analysed the intensity of pain, pulmonary function, respiratory muscle strength, and use of analgesia medications. Outcomes were evaluated before surgery, immediately after, 24 and 48 h after ICU admission. Results Forty-fve patients were included. Regarding pain perception, there was no diference between groups (p=0.172), but there was a signifcant reduction in pain intensity for patients receiving TENS after frst physiotherapy session compared to baseline (4.7±3.2 vs 3.3±2.6; p<0.05). All groups had a decrease in forced vital capacity (FVC) after surgery (p<0.001). There was no diference between the groups regarding the use of analgesic medications, but a higher intake of morphine and acetaminophen were observed for the control (p=0.037) and placebo group (p=0.035), respectively. Conclusion The use of TENS provides a little beneft of pain (in the frst 12 h) but failed to demonstrate any improvement in the recovery of ICU patients after 48 h of posterolateral thoracotomy.