Assessing baroreflex sensitivity in the sequences technique: local versus global approach

The sequences technique is the most used time domain technique for the assessment of arterial baroreceptor reflex sensitivity (BRS) and is based in the analysis of the beat-to-beat spontaneous variability of systolic blood pressure and heart period. Although a common used method, the sequences technique imposes the setting of several parameters to determine what is a valid baroreflex event and no consensual opinion about these parameters is found in the literature. The theory is overlooked, and linear regression over three values is the usual procedure. The methodology itself can be questionable and the estimator has not been clearly examined regarding its statistical properties, namely bias and variance. In this work, an alternative estimator that we have been using is evaluated and compared with the traditional approach, considering real and simulated data. The results obtained show that the proposed estimator is less biased and presents lower variance than the traditional approach