The impact of calibration approaches on the accuracy of oscillometric central aortic blood pressure measurement

Abstract

Background: Two fully automated oscillometric devices have become available for the noninvasive assessment of central aortic blood pressure (BP). They tend, however, to underestimate SBP. It has been proposed that calibration by mean/diastolic instead of systolic/diastolic brachial BP may reduce this bias. The present work compares the accuracy of these two calibrations in the Mobil-O-Graph. Methods: Post-hoc analysis of the largest validation study on noninvasive assessment of central BP so far. Data on both calibration approaches were available in 159 patients without atrial fibrillation, who underwent simultaneous invasive and noninvasive assessment of central BP. Noninvasive BP measurements were conducted using the SphygmoCor XCEL (calibration by systolic/diastolic brachial BP only) and the Mobil-O-Graph (calibration by both systolic/diastolic and mean/diastolic brachial BP). Results: Measurements of both devices and both calibration methods revealed highly significant correlations for systolic and diastolic central BP with invasively assessed BP (P < 0.001 each). Calibration by mean/diastolic and systolic/diastolic BP yielded similar correlations for central DBP (R 2 0.56 vs. R 2 0.55, P = 0.919). Correlation of central SBP, however, was significantly lower using calibration by mean/diastolic brachial BP (R 2 0.86 vs. R 2 0.74, P = 0.002). Numerically, the SphygmoCor device revealed the highest correlation (R 2 0.92 for central SBP and 0.72 for central DBP; P < 0.001 each). Calibration by systolic/diastolic brachial BP was associated with an underestimation of central SBP using both the SphygmoCor and the Mobil-O-Graph. Calibration by mean/diastolic brachial BP, instead, was associated with an overestimation, which was numerically comparable (4.8 ± 11.3 vs. −4.2 ± 8.0). The calibration method had little effects on the biases of diastolic measurements. Conclusion: Calibration by mean/diastolic instead of systolic/diastolic brachial BP led to an overestimation instead of underestimation of central SBP without improving accuracy. Hence, mean/diastolic calibration is not necessarily superior to systolic/diastolic calibration and the optimal approach has to be determined in a device-specific manner.

Feasibility of non‐invasive measurement of central blood pressure and arterial stiffness in shock

“…In addition, all of the central pulse wave analysis parameters are calculated from the average central pressure pulse. These two current automated oscillometric monitors are able to assess central blood pressure with acceptable accuracy, as seen recently 22,23 …”

“…Our previous studies showed an excellent accuracy for the Mobil-o-Graph PWA and SphygmoCor XCEL regarding central blood pressure measurement in haemodynamic stable patients. 22,23 In a study by Hashimoto et al, SBP amplification at the femoral artery was found to be comparable to SBP amplification at After cases of device malfunction, death before complete assessment or patient transfer to another hospital were excluded.…”

“…These two current automated oscillometric monitors are able to assess central blood pressure with acceptable accuracy, as seen recently. 22,23 Reporting of the study conforms to broad EQUATOR guidelines (Simera et al January 2010 issue of EJCI).…”

Relation between Oscillometric Measurement of Central Hemodynamics and Left Ventricular Hypertrophy in Hypertensive Patients

“…A smaller cuff was used when the arm circumference was 24 cm. After measuring the brachial BP, the cuff was instantly inflated, and the brachial artery pressure waves were recorded at the DBP level for 10 s. The central pressure waveform was calculated using a generalized transfer function [11], and the calibration by the systolic/diastolic brachial BP was used [20].…”

Updates about TC-25: The Technical Committee on Biological and Medical Measurements

“…As a consequence, BP monitors can pass the validation tests in the presence of clinically significant differences occurring in the BP estimated values in some individuals [9], [14]. The accuracy of NIBP measurement instruments based on oscillometric methods and their calibration continues to be an object of research interest, and different approaches have been proposed to solve these issues, for example by the application of artificial intelligence [14], [16], by focusing on the cuff related effects [17] or on the oscillometric blood pressure waveform [15], by analyzing the problems related to the NIPB instrument calibration [18]- [21]. The TC-25 SCOBPM, aware of the current BP measurement metrological problems and challenges, works to provide an objective reference for measuring systemic arterial BP in humans, in the form of definitions and descriptions of objective techniques and traceable calibration procedures that are independent of the specific devices, apparatus, instruments, or computing devices that may be used in BP measurements.…”