Arterial pressure control during non-hypo/hypertensive changes incentral venous volume: assessment with multivariate autoregressivemodeling

摘要

To evaluate how small decreases and increases of central volumeinfluence heart rate and arterial pressure control multivariateautoregressive techniques were used to quantify the interactions betweenrespiration, RR interval and arterial blood pressure during randominterval breathing, at 3 low levels of lower body negative pressure and3 low levels of increased central volume. In addition to the classicspectral parameters for each signal, the algorithms were used to derivethe closed-loop feedforward and feedback gains for the baroreflex andthe effects of respiration on RR interval. With reductions of centralvolume below control, baroreflex and respiratory sinus arrhythmia gainswere generally reduced, while with increases of volume above control,they increased only for the first two levels, and decreased at thehighest volume. These findings indicate that reflex heart rate controlis maximum with mild hypervolemia, and are consistent with the presenceof the Bainbridge reflex in healthy humans