Abstract P200: Predictive Value of the Pressor Response to a Voluntary Apnea
Previously, we have shown that chemoreflex control of sympathetic nerve activity (SNA) is hypersensitive in patients with obstructive sleep apnea (OSA), and this is manifest as an exaggerated SNA and blood pressure response to voluntary apneas. We hypothesized that an exaggerated systolic arterial pressure (SAP) response to apnea in OSA patients is detectable with standard auscultation in a clinical setting. Methods: Beat-to-beat blood pressure (Finometer) and standard auscultatory blood pressure were measured in triplicate during quiet rest and immediately following a 20 sec voluntary end-expiratory breath-hold (apnea) in 42 patients with OSA and in 34 control subjects without OSA. Pulse oximetry was also measured and the nadir of oxygen saturation was obtained for each breath-hold. Mean systolic blood pressure changes during breath-holding were compared between groups and among those with a score of 10 or higher on Epworth and those with a score of 9 and lower. Results: Post-apnea SAP, measured by auscultation, increased significantly more in patients with OSA (+7.5 +/- 2.3 mmHg, p<0.01) as compared to healthy control subjects (+2.4 +/- 1.5 mmHg). In addition, the response in control subjects was not different from zero. Conclusion: These data demonstrate that measurement of the SAP response to a voluntary breath-hold can distinguish patients with OSA from normotensive subjects without OSA. Further studies will seek to better define the predictive power of this physiologic screening tool for OSA and hypertension.
- © 2013 by American Heart Association, Inc.