O1 The effect of transcutaneous electrical stimulation of the submental area on the cardiorespiratory response in normal and awake subjects

<h3>Background</h3> Electrical stimulation has recently been introduced to treat patients with Obstructive sleep apnoea (OSA). There are, however, few data on the effects of transcutaneous submental electrical stimulation (TES) on the cardiovascular system. We studied the effect of TES on cardiorespiratory variables in healthy volunteers during head-down-tilt (HDT) induced baroreceptor loading. <h3>Method</h3> Cardiorespiratory parameters (blood pressure, heart rate, minute ventilation, oxygen saturation, and end-tidal CO2/O2 concentration) were recorded seated, supine, and during HDT (50°) under normoxic, hypercapnic (FiCO2 5%) and poikilocapnic hypoxic (FiO2 12%) conditions. Blood pressure (BP) was measured non-invasively and continuously (Finapres). TES was individually titrated to skin sensation and gentle stimulation. We studied all participants twice on different days, once without and once with TES.¹ <h3>Results</h3> We studied 13 healthy subjects (age 29 (12) years, 6 female, body mass index (BMI) 23.23 (1.6) kg·m-2). A three-way ANOVA indicated that BP decreased significantly with TES (systolic: p=4.93E-06, diastolic: p=3.48E-09, mean: p=3.88E-08). Change in gas condition (systolic: p=0.0402, diastolic: p=0.0033, mean: p= 0.0034) and different postures (systolic: 8.49E-08, diastolic: p=6.91E-04, mean: p=5.47E-05) similarly impacted on BP control. When tested for interaction, there were no significant associations between the three different factors electrical stimulation, gas condition, or posture, except for an effect on minute ventilation (gas condition/posture p=0.0369). <h3>Conclusion</h3> Transcutaneous electrical stimulation reduces blood pressure significantly. Similarly, postural changes and variations in inspired gas impact on blood pressure control. Further research is needed to study the effects of TES on cardiovascular parameters over the long term and to evaluate its efficacy and safety in OSA patients. <h3>Reference</h3> Alsharifi A, Kaltsakas G, Pengo MF, Parati G, Serna-Pascual M, Rafferty G, Steier J. The effect of transcutaneous electrical stimulation of the submental area on the cardiorespiratory response in normal and awake subjects. <i>Frontiers in physiology</i>, 2023;<b>14</b>:1089837. https://doi.org/10.3389/fphys.2023.1089837