Reliability of pulse waveform separation analysis

effects of posture and fasting

Abstract

Objective: 

Oscillometric pulse wave analysis devices enable, with relative simplicity and objectivity, the measurement of central hemodynamic parameters. The important parameters are central blood pressures and indices of arterial wave reflection, including wave separation analysis (backward pressure component P_b and reflection magnitude). This study sought to determine whether the measurement precision (between-day reliability) of P_b and reflection magnitude: exceeds the criterion for acceptable reliability; and is affected by posture (supine, seated) and fasting state.

Methods: 

Twenty healthy adults (50% female, 27.9 years, 24.2 kg/m²) were tested on six different mornings: 3 days fasted, 3 days nonfasted condition. On each occasion, participants were tested in supine and seated postures. Oscillometric pressure waveforms were recorded on the left upper arm.

Results: 

The criterion intra-class correlation coefficient value of 0.75 was exceeded for P_b (0.76) and reflection magnitude (0.77) when participants were assessed under the combined supine-fasted condition. The intra-class correlation coefficient was lowest for P_b in seated-nonfasted condition (0.57), and lowest for reflection magnitude in the seated-fasted condition (0.56). For P_b, the smallest detectible change that must be exceeded in order for a significant change to occur in an individual was 2.5 mmHg, and for reflection magnitude, the smallest detectable change was 8.5%.

Conclusion: 

Assessments of P_b and reflection magnitude are as follows: exceed the criterion for acceptable reliability; and are most reliable when participants are fasted in a supine position. The demonstrated reliability suggests sufficient precision to detect clinically meaningful changes in reflection magnitude and P_b.