Peer-Reviewed Journal Details
Mandatory Fields
Deegan, BM;Devine, ER;Geraghty, MC;Jones, E;OLaighin, G;Serrador, JM
2010
November
Journal Of Applied Physiology
The relationship between cardiac output and dynamic cerebral autoregulation in humans
Published
WOS: 37 ()
Optional Fields
ARTERY BLOOD VELOCITY LEFT-VENTRICULAR VOLUMES FLOW VELOCITY GENDER-DIFFERENCES ORTHOSTATIC STRESS AUTO-REGULATION EXERCISE PRESSURE PERFUSION ECHOCARDIOGRAPHY
109
1424
1431
Cerebral autoregulation adjusts cerebrovascular resistance in the face of changing perfusion pressures to maintain relatively constant flow. Results from several studies suggest that cardiac output may also play a role. We tested the hypothesis that cerebral blood flow would autoregulate independent of changes in cardiac output. Transient systemic hypotension was induced by thigh-cuff deflation in 19 healthy volunteers (7 women) in both supine and seated positions. Mean arterial pressure (Finapres), cerebral blood flow (transcranial Doppler) in the anterior (ACA) and middle cerebral artery (MCA), beat-by-beat cardiac output (echocardiography), and end-tidal PCO2 were measured. Autoregulation was assessed using the autoregulatory index (ARI) defined by Tiecks et al. (Tiecks FP, Lam AM, Aaslid R, Newell DW. Stroke 26: 1014-1019, 1995). Cerebral autoregulation was better in the supine position in both the ACA [supine ARI: 5.0 +/- 0.21 (mean +/- SE), seated ARI: 3.9 +/- 0.4, P = 0.01] and MCA (supine ARI: 5.0 +/- 0.2, seated ARI: 3.8 +/- 0.3, P = 0.004). In contrast, cardiac output responses were not different between positions and did not correlate with cerebral blood flow ARIs. In addition, women had better autoregulation in the ACA (P = 0.046), but not the MCA, despite having the same cardiac output response. These data demonstrate cardiac output does not appear to affect the dynamic cerebral autoregulatory response to sudden hypotension in healthy controls, regardless of posture. These results also highlight the importance of considering sex when studying cerebral autoregulation.
8750-7587
10.1152/japplphysiol.01262.2009
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