Development and clinical application of a new technique for detecting 'sleep blood pressure surges' in sleep apnea patients based on a variable desaturation threshold

Obstructive sleep apnea (OSA) places an enormous pressure load on the cardiovascular system by inducing a temporary blood pressure (BP) surge (sleep BP surge (SLBPS)), often resulting in target organ damage and cardiovascular events, such as left ventricular hypertrophy, sudden death, myocardial infarction and stroke. Accurate measurement of SLBPS would be valuable for the risk stratification of OSA patients. We developed a new oxygen-triggered BP monitoring system based on a variable SpO 2 threshold (VT algorithm) to selectively detect severe SLBPS, which are associated with morbidity, and evaluated its performance in comparison with a previous technique based on a fixed SpO 2 threshold (FT algorithm). In 23 OSA patients, the correlation between individual minimum SpO 2 values and SLBPS was not significant when the FT algorithm was used alone ( r =0.400, P =0.058) but became significant ( r =0.725, P