1. The Sit-to-Stand Technique for the Measurement of Dynamic Cerebral Autoregulation
- Author
-
Sorond, Farzaneh A., Serrador, Jorge M., Jones, Richard N., Shaffer, Michele L., and Lipsitz, Lewis A.
- Subjects
- *
CEREBRAL circulation , *TRANSCRANIAL Doppler ultrasonography , *BLOOD flow measurement , *BLOOD pressure , *REGULATION of blood circulation , *HEALTH outcome assessment , *PHYSIOLOGICAL stress , *AGING , *ANALYSIS of variance , *CEREBRAL arteries , *COMPARATIVE studies , *HEMODYNAMICS , *HOMEOSTASIS , *LIGATURE (Surgery) , *RESEARCH methodology , *MEDICAL cooperation , *RESEARCH , *RESEARCH funding , *THIGH , *EVALUATION research , *BODY movement - Abstract
Abstract: Measurement of cerebral autoregulation is important for the evaluation and management of a number of clinical disorders that affect cerebral blood flow. We currently lack simple bedside measures that mimic common physiologic stresses. Therefore, we evaluated a new sit-to-stand technique as an alternative method to the frequently-used thigh-cuff technique in healthy volunteers. Continuous middle cerebral artery (MCA) blood flow velocities (BFV) and arterial blood pressure (ABP) were measured in response to standing from a sitting position, or rapid thigh-cuff deflation in 24 healthy subjects (50 ± 22 y). Autoregulatory index (ARI) was calculated as the BFV response for step changes in ABP using a second-order differential equation with a set of parameters that can be used to grade the performance of autoregulation. Of these 24 subjects, 30% could tolerate only two thigh-cuffs and refused to proceed with the third cuff, whereas none of our subjects had any difficulty with performing the three sit-to-stand trials. The two techniques produced similar changes in mean ABP, but the times to nadir of the blood pressure and BFV were significantly faster for the thigh-cuff. The mean group ARIs were similar between the two techniques. Although between-subjects variability was higher for sit-to-stand ARIs, the within-subject sit-to-stand ARI variability was small. Thus, for the assessment of cerebral autoregulation, the sit-to-stand procedure is well tolerated and produces ARI values that have low within-subject variability. The sit-to-stand technique appears to be a suitable measure of individual ARI values for inferring dynamic cerebral autoregulation. E-mail: fsorond@partners.org [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
- View/download PDF