title: The repeated sit-to-stand maneuver is a superior method for cardiac baroreflex assessment: a comparison with the modified Oxford method and Valsalva maneuver.
abstract: Baroreflex assessment has diagnostic and prognostic utility in the clinical and research environments, and there is a need for a reliable, simple, noninvasive method of assessment. The repeated sit-to-stand method induces oscillatory changes in blood pressure (BP) at a desired frequency and is suitable for assessing dynamic baroreflex sensitivity (BRS). However, little is known about the reliability of this method and its ability to discern fundamental properties of the baroreflex. In this study we sought to: 1) evaluate the reliability of the sit-to-stand method for assessing BRS and compare its performance against two established methods (Oxford method and Valsalva maneuver), and 2) examine whether the frequency of the sit-to-stand method influences hysteresis. Sixteen healthy participants underwent three trials of each method. For the sit-to-stand method, which was performed at 0.1 and 0.05 Hz, BRS was quantified as an integrated response (BRSINT) and in response to falling and rising BP (BRSDOWN and BRSUP, respectively). Test retest reliability was assessed using the intraclass correlation coefficient (ICC). Irrespective of frequency, the ICC for BRSINT during the sit-to-stand method was ≥0.88. The ICC for a rising BP evoked by phenylephrine (PEGAIN) in the Oxford method was 0.78 and ≤0.5 for the remaining measures. During the sit-to-stand method, hysteresis was apparent in all participants at 0.1 Hz but was absent at 0.05 Hz. These findings indicate the sit-to-stand method is a statistically reliable BRS assessment tool and suitable for the examination of baroreflex hysteresis. Using this approach we showed that baroreflex hysteresis is a frequency-dependent phenomenon.
authors.affiliation: Cardiovascular Systems Laboratory; Centre for Translational Physiology, University of Otago, Wellington, New Zealand;
authors.forename: H M
authors.initials: HM
authors.lastname: Horsman
authors.affiliation: Cardiovascular Systems Laboratory; Centre for Translational Physiology, University of Otago, Wellington, New Zealand;
authors.forename: Y C
authors.initials: YC
authors.lastname: Tzeng
authors.affiliation: Cardiovascular Systems Laboratory; Centre for Translational Physiology, University of Otago, Wellington, New Zealand;
authors.forename: D C
authors.initials: DC
authors.lastname: Galletly
authors.affiliation: Cardiovascular Systems Laboratory; Centre for Translational Physiology, University of Otago, Wellington, New Zealand; Department of Physiology, University of Otago, Dunedin, New Zealand; and Department of Human Sciences, Macquarie University, Sydney, Australia karen.peebles@mq.edu.au.
authors.forename: K C
authors.initials: KC
authors.lastname: Peebles
mesh_terms: D000328:Adult; D017704:Baroreflex / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology; D005260:Female; D006321:Heart / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D009068:Movement / Q000502:physiology*; D015203:Reproducibility of Results; D014636:Valsalva Maneuver / Q000502:physiology*; D055815:Young Adult
keywords: baroreflex; blood pressure; hysteresis; reliability; repeated sit-to-stand method