Measurement of Systolic Blood Pressure Using POCUS With Color Doppler Compared to with an Intraarterial Line

In some clinical circumstances, it may be difficult to accurately measure systolic blood pressure (SBP) using direct auscultation technique or an automated oscillometric cuff pressure device. As an alternative method, this study compared the measurement of SBP using point of care ultrasound (POCUS) with color Doppler to the measurement of SBP using an intraarterial catheter.

Study subjects were 50 patients in an intensive care unit who had an intraarterial catheter placed for monitoring blood pressure. The intraarterial catheter systolic pressure was recorded and compared to the contemporaneous measurement of SBP using POCUS with color power Doppler (CPD). The operator placed the Doppler sample volume over the brachial artery with ipsilateral inflation of a prepositioned upper arm blood pressure cuff that was inflated sufficiently to ablate blood flow in the target artery. The blood pressure cuff was then deflated until there was return of CPD signal in the brachial artery. At this moment, the corresponding blood pressure was noted on a sphygmomanometer attached to the blood pressure cuff. The values of the two methods were compared using standard statistical technique.

The intraarterial systolic pressures and CPD systolic pressures by POCUS were well correlated with a Pearsons correlation coefficient of 0.96. Bland-Altman analysis of bias and limits of agreement indicated that the POCUS with CPD measurement was sufficiently accurate to have clinical utility.

The use of POCUS with CPD to measure SBP may have utility in situations where direct auscultation or automated oscillometeric cuff pressure measurements may be unreliable.