Identification of the cuff transfer function increases indirect blood pressure measurement accuracy

At present, oscillometric blood pressure meters are among the most commonly used medical devices in the world. While substantial effort has been invested in developing more reliable evaluation algorithms, the actual hardware setup-an inflatable cuff and a pressure transducer connected to it-remained basically unchanged since the mid 19th century. Our research work has concentrated on developing an experimental test set-up to determine the transfer function of cuffs. The relationship between the volume pulses in the brachial artery and the pressure changes induced in the bladder was studied for cuffs of different size and placement. Significant differences have been found between small-, standard- and large-size cuffs. The placement of the bladder (tight, loose, upside down, over a shirtsleeve) remarkably affects the estimated systolic and diastolic pressures. Based on the reported research work it is possible to identify an improperly applied cuff that would result in a misleading BP measurement. Distortion caused by miscuffing is rather patient specific.