Cerebral blood flow velocity response to induced and spontaneous sudden changes in arterial blood pressure

Valsalva maneuver Cerebral autoregulation
DOI: 10.1152/ajpheart.2001.280.5.h2162 Publication Date: 2017-12-22T18:03:04Z
ABSTRACT
The influence of different types maneuvers that can induce sudden changes arterial blood pressure (ABP) on the cerebral flow velocity (CBFV) response was studied in 56 normal subjects (mean age 62 yr, range 23–80). ABP recorded finger with a Finapres device, and bilateral recordings CBFV were performed Doppler ultrasound middle arteries. Recordings at rest (baseline) during thigh cuff test, lower body negative pressure, cold pressor hand grip, Valsalva maneuver. From baseline recordings, positive spontaneous transients also selected. Stability Pco 2 monitored transcutaneous measurements. Dynamic autoregulatory index (ARI), impulse, step responses obtained for 1-min segments data eight conditions by fitting mathematical model to ABP-CBFV transient (Aaslid's model) Wiener-Laguerre moving-average method. Impulse similar right- left-side their temporal pattern not influenced type Step showed rise time 0 then started fall back original level, indicating an active autoregulation. ARI independent maneuver, giving overall mean 4.7 ± 2.9 ( n = 602 recordings). Amplitudes impulse responses, however, significantly maneuver highly correlated resistance-area product before change r −0.93, P < 0.0004). These results suggest amplitude is sensitive point operation instantaneous relationship, which be shifted maneuvers. Various degrees sympathetic nervous system activation resulting from ABP-stimulating reflected dynamic within physiological ABP.
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