This Article Order Full text via Infotrieve Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Lagi, A. Articles by Colzi, L. Search for Related Content PubMed PubMed Citation Articles by Lagi, A. Articles by Colzi, L.

Stroke, Vol 25, 1771-1775, Copyright © 1994 by American Heart Association

ARTICLES

Cerebral autoregulation in orthostatic hypotension. A transcranial Doppler study

A Lagi, S Bacalli, S Cencetti, C Paggetti and L Colzi
Internal Medicine Department, S. Maria Nuova Hospital, Florence, Italy.

BACKGROUND AND PURPOSE: Transcranial Doppler measurements of blood flow velocity permit an assessment of variations in intracranial hemodynamics in response to acute arterial pressure variations. The purpose of this study was to scan healthy volunteers and patients with autonomic failure for differences in cerebral hemodynamic patterns under an acute hypotensive stimulus. METHODS: We used transcranial Doppler monitoring of blood flow velocity in the middle cerebral artery and noninvasive monitoring of arterial blood pressure and heart rate before, during, and after acute arterial hypotension induced by reactive hyperemia of the lower limbs. RESULTS: After maximum hypotension, the mean blood flow velocity was higher in the healthy volunteers than in the patients. In the healthy subjects mean velocity rose significantly (P < .01) higher than arterial blood pressure after 30 seconds and 60 seconds; in the patients mean velocity and arterial pressure moved in parallel fashion. The diastolic blood flow velocity increased more in the control group than in the patients during the early stages of the test; furthermore, only in the healthy volunteers did it increase significantly more than arterial pressure after 30 seconds and 60 seconds. Regarding the pulsatility index, the differences between the two groups were similar to the diastolic velocity results. CONCLUSIONS: (1) Monitoring of mean blood flow velocity showed the ability to maintain an adequate cerebral blood flow in healthy subjects; this mechanism was not efficient in the patients with autonomic failure. (2) Diastolic velocity and pulsatility index values clearly showed that only in healthy subjects were cerebral hemodynamics relatively independent of pressure values.

This article has been cited by other articles:

				A. M. Kaki and W. A. Almarakbi Does Patient Position Influence the Reading of the Bispectral Index Monitor? Anesth. Analg., December 1, 2009; 109(6): 1843 - 1846. [Abstract] [Full Text] [PDF]

				I. Taneja, M. S. Medow, J. L. Glover, N. K. Raghunath, and J. M. Stewart Increased vasoconstriction predisposes to hyperpnea and postural faint Am J Physiol Heart Circ Physiol, July 1, 2008; 295(1): H372 - H381. [Abstract] [Full Text] [PDF]

				C. H. Gibbons and R. Freeman Delayed orthostatic hypotension: A frequent cause of orthostatic intolerance. Neurology, July 11, 2006; 67(1): 28 - 32. [Abstract] [Full Text] [PDF]

				H. Guo, N. Tierney, F. Schaller, P. B. Raven, S. A. Smith, and X. Shi Cerebral autoregulation is preserved during orthostatic stress superimposed with systemic hypotension J Appl Physiol, June 1, 2006; 100(6): 1785 - 1792. [Abstract] [Full Text] [PDF]

				A. G. Hermosillo, K. Jauregui-Renaud, A. Kostine, M. F. Marquez, J. L. Lara, and M. Cardenas Comparative study of cerebral blood flow between postural tachycardia and neurocardiogenic syncope, during head-up tilt test Europace, January 1, 2002; 4(4): 369 - 374. [Abstract] [PDF]

				D. J. Mehagnoul-Schipper, L. C. M. Vloet, W. N. J. M. Colier, W. H. L. Hoefnagels, and R. W. M. M. Jansen Cerebral Oxygenation Declines in Healthy Elderly Subjects in Response to Assuming the Upright Position Stroke, July 1, 2000; 31(7): 1615 - 1620. [Abstract] [Full Text] [PDF]

				P. J. Mahony, R. B. Panerai, S. T. Deverson, P. D. Hayes, and D. H. Evans Assessment of the Thigh Cuff Technique for Measurement of Dynamic Cerebral Autoregulation Stroke, February 1, 2000; 31(2): 476 - 480. [Abstract] [Full Text] [PDF]

				V. Novak, P. Novak, J. M. Spies, and P. A. Low Autoregulation of Cerebral Blood Flow in Orthostatic Hypotension Stroke, January 1, 1998; 29(1): 104 - 111. [Abstract] [Full Text] [PDF]

				R. L. Bondar, P. T. Dunphy, P. Moradshahi, M. S. Kassam, A. P. Blaber, F. Stein, and R. Freeman Cerebrovascular and Cardiovascular Responses to Graded Tilt in Patients With Autonomic Failure Stroke, September 1, 1997; 28(9): 1677 - 1685. [Abstract] [Full Text]

				A. P. Blaber, R. L. Bondar, F. Stein, P. T. Dunphy, P. Moradshahi, M. S. Kassam, and R. Freeman Transfer Function Analysis of Cerebral Autoregulation Dynamics in Autonomic Failure Patients Stroke, September 1, 1997; 28(9): 1686 - 1692. [Abstract] [Full Text]