EVALUATING INDIRECT BLOOD PRESSURE TECHNIQUES–A COMPARATIVE STUDY

An accurate systolic blood pressure (SBP) can now be measured indirectly in all infants & children with an ultrasonic flow detector (UFD) and an inflatable cuff of appropriate size & design. Two semi-automatic blood pressure devices, Arteriosonde 1010 (A) & Infrasonde (I), are purported to accurately measure both SBP and diastolic blood pressure (DBP). A two-Pronged study was designed to evaluate the accuracy of indirect blood pressure obtained with A, I, & a new plastic (Pedisphyg) cuff (PC). In part one, with the cuff of either A, I, or PC systems applied to the upper arm in random and sequential fashion & with a catheter in the ipsilateral subclavian artery, simultaneous direct & indirect pressures were recorded & compared. In part two, A, I, & PC systolic BP values alone were compared by performing simultaneous measurements on both upper arms of selected infants previously shown to have identical SPP in both arms. Comparisons were made hy random application of A, I, & PC to each arm. In this two-pronged study, 125 comparisons revealed that (1) with a properly sized plastic cuff and an ultrasonic flow detector, systolic BP can be measured accurately but not diastolic BP, (2) A & I frequently fail to sound a distinct signal to mark SBP accurately, & even with a relatively good signal the plastic cuff & UFD system is more accurate than A or I, (3) neither A nor I accurately marks DBF and should not he relied upon for this measurement.