Influence of cuff pressures of automatic sphygmomanometers on pulse oximetry measurements

Information about blood arterial oxygen saturation (SpO(2)) is crucial in critical care settings or home health monitoring during the COVID-19 pandemic. Also, we need to identify the factors that affect the SpO(2) measurement. In this paper, the effect of compression of the cuff during noninvasive blood pressure (NIBP) measurement on the SpO(2) results was investigated. A custom-made system was used for simultaneous measurement of NIBP and SpO(2). The study was conducted on 213 subjects aged between 21 and 93, with a systolic blood pressure of (94 to 194) mmHg, diastolic blood pressure of (52-98) mmHg, and 994 NIBP readings were used for the analysis. During the NIBP measurement, momentary changes in SpO(2) can reach +/- 17% and are in most cases positive (mean 2.9%). The change was not correlated with sex, age, height, body weight, BMI, HR and blood pressure. The obtained results show that frequent NIBP measurements may lead to wrong conclusions about SpO(2). In our study, pressure measurements mainly caused the increase of blood oxygenation level.