Purpose: Severity of hypoxemic events resulting from obstructive sleep apnea (OSA) is correlated with increased risk of complications and sudden death. We studied the use of a peripheral transcutaneous electrical stimulus (TES) on the magnitude and duration of sleep apnea associated hypoxemia in postoperative patients at high risk for OSA. Methods: In this randomized, double-blind, controlled, single-centre trial, 106 adult patients undergoing elective surgery who were at medium to high risk for OSA (sleep apnea clinical scores of 18–35) were randomized to either TES (active stimulus group, n = 53) or control (non-stimulus group, n = 53) during their stay in the postanesthesia care unit. Transcutaneous electrical stimuli were delivered at threshold oxygen saturation measurements (SpO2) ≤ 93%. The primary endpoint was the SpO2 area under the curve (AUC) < 90%. Secondary endpoints included the percentage of patients with SpO2 < 90%, duration SpO2 < 90%, lowest SpO2 in the first hour, and adverse events associated with TES. Results: Compared with controls (n = 45), those in the active group (n = 34) showed a decreased SpO2 AUC < 90% (median 0.0 vs 15.2 % sec, respectively; P = 0.009), a smaller percentage of subjects with SpO2 < 90% (47% active vs 71% control; P = 0.03), a shorter duration of SpO2 < 90% (median 0.0 vs 19.1 sec, respectively; P = 0.01), and a higher nadir of SpO2 recorded during the first hour (median 90.5% vs 87.9%, respectively; P = 0.04). Among patients with at least one SpO2 < 93%, there were fewer with SpO2 < 90% in the active group (55% vs 84%, respectively; P = 0.009). No adverse events related to TES were reported. Conclusion: In postoperative surgical patients at risk for OSA, peripheral transcutaneous electrical stimulation applied during apneic episodes decreased the duration and magnitude of hypoxemia. Trial registration: www.ClinicalTrials.gov (NCT02554110); registered 18 September, 2015.
Smith, H. M., Kilger, J., Burkle, C. M., Schroeder, D. R., & Gali, B. (2019). Peripheral electrical stimulation reduces postoperative hypoxemia in patients at risk for obstructive sleep apnea: a randomized-controlled trial. Canadian Journal of Anesthesia, 66(11), 1296–1309. https://doi.org/10.1007/s12630-019-01451-3