COMPARISON OF INTRAARTERIAL WITH CONTINUOUS NONINVASIVE BLOOD-PRESSURE MEASUREMENT IN POSTOPERATIVE PEDIATRIC-PATIENTS

Objective. The purpose of this study was to estimate the accuracy, bias, and frequency response of continuous blood pressure monitoring using finger photoplethysmography in children. Methods. To compare arterial blood pressure measured using the Finapres device with simultaneously measured intraarterial blood pressure we studied 27 randomly selected postoperative pediatric patients who were receiving a variety of inotropic and vasoactive agents at a cardiac intensive care unit in university-affiliated pediatric hospital. Results. Sixty-two of 66 attempts (94%) to obtain a noninvasive blood pressure measurement were successful. A total of 37,351 paired blood pressure measurements from 53 records were compared, revealing a measurement bias of -18.6 mm Hg for systolic blood pressure and -13.4 mm Hg for diastolic blood pressure. The measurement bias increased proportionately to blood pressure, with systolic and diastolic gains between the noninvasive and intraarterial techniques of 0.86 and 0.75 mm Hg/mm Hg, respectively. The variation bias during each recording epoch, as measured by standard deviation of bias, was low (mean sigma(systolic) = 2.9 mm Hg; mean sigma(diastolic) = 2.0 mm Hg). The frequency response between the intraarterial and noninvasive pressure waveforms was flat to 10 Hz and approximately equal to 1. Conclusions. Substantial measurement bias exists between this noninvasive blood pressure measurement technique and intraarterial blood pressure. Measurements of the intrapatient variability and frequency response analysis suggest that the noninvasive technique accurately tracks intraarterial blood pressure over the short term. This technique may have useful applications in settings where intraarterial monitoring is undesirable or unobtainable.