A Pulse Wave Velocity Based Method to Assess the Mean Arterial Blood Pressure Limits of Autoregulation in Peripheral Arteries.

ABSTRACT: Background: Constant blood flow despite changes in blood pressure, a phenomenon called autoregulation, has been demonstrated for various organ systems. We hypothesized that by changing hydrostatic pressures in peripheral arteries, we can establish these limits of autoregulation in peripheral arteries based on local pulse wave velocity (PWV). Methods: Electrocardiogram and plethysmograph waveforms were recorded at the left and right index fingers in 18 healthy volunteers. Each subject changed their left arm position, keeping the right arm stationary. Pulse arrival times (PAT) at both fingers were measured and used to calculate PWV. We calculated ?PAT (?PWV), the differences between the left and right PATs (PWVs), and compared them to the respective calculated blood pressure at the left index fingertip to derive the limits of autoregulation. Results: ?PAT decreased and ?PWV increased exponentially at low blood pressures in the fingertip up to a blood pressure of 70 mmHg, after which changes in ?PAT and ?PWV were minimal. The empirically chosen 20 mmHg window (75-95 mmHg) was confirmed to be within the autoregulatory limit (slope = 0.097, p = 0.56). ?PAT and ?PWV within a 20 mmHg moving window were not significantly different from the respective data points within the control 75-95 mmHg window when the pressure at the fingertip was between 56 and 110 mmHg for ?PAT and between 57 and 112 mmHg for ?PWV. Conclusions: Changes in hydrostatic pressure due to changes in arm position significantly affect peripheral arterial stiffness as assessed by ?PAT and ?PWV, allowing us to estimate peripheral autoregulation limits based on PWV.

SUBMITTER: Tripathi A 

PROVIDER: S-EPMC5681752 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature