The effect of transcutaneous electric nerve stimulation on postoperative pain and pulmonary function

Surgery on the upper abdomen is associated with marked postoperative pulmonary dysfunction that results largely from restriction of lung expansion secondary to incisional pain. This study, utilizing three groups of patients (a control group, a sham group, and a group receiving transcutaneous electric nerve stimulation [TENS] for pain control), was designed to determine whether this modality is effective in alleviating postoperative pain. Spirometry, arterial blood gases, clinical as well as radiologic evidence of postoperative pulmonary complications, and the frequency of analgesic requests were determined. Of the 40 patients studied, the 15 receiving TENS required only 4.7 +/- 2.5 doses of narcotic analgesics in the first 72 hours as opposed to 10.1 +/- 2.7 and 10.4 +/- 2.7 in the other two groups (P less than 0.005). There were a total of six postoperative pulmonary complications, all occurring in the groups not receiving TENS. Postoperative arterial Po2, vital capacity, and functional residual capacity were least depressed in the TENS group. The data suggest that TENS minimizes the tendency toward postoperative alteration in respiratory mechanics and decreases the incidence of pulmonary complications by alleviating incisional pain.