This Article Full Text Full Text (PDF) All Versions of this Article: 38/2/402    most recent 01.STR.0000254551.92209.5cv1 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 Lavinio, A. Articles by Czosnyka, M. Search for Related Content PubMed PubMed Citation Articles by Lavinio, A. Articles by Czosnyka, M. Related Collections Cerebrovascular disease/stroke Other hypertension Other diagnostic testing Brain Circulation and Metabolism Doppler ultrasound, Transcranial Doppler etc. Other Research

(Stroke. 2007;38:402.)
© 2007 American Heart Association, Inc.

Research Reports

Noninvasive Evaluation of Dynamic Cerebrovascular Autoregulation Using Finapres Plethysmograph and Transcranial Doppler

Andrea Lavinio, MD; Eric Albert Schmidt, MD, PhD; Christina Haubrich, MD; Piotr Smielewski, PhD; John D. Pickard, F Med Sci Marek Czosnyka, PhD

From the Department of Academic Neurosurgery, Addenbrooke’s Hospital, Cambridge, UK (A.L., E.A.S., C.H., P.S., J.D.P., M.C.); Institute of Anesthesiology and Intensive Care Medicine, University of Brescia, Brescia, Italy (A.L.); Department of Neurosurgery, Hopital Purpan, Toulouse, France (E.A.S.); and Department of Neurology, University Hospital Aachen, Aachen, Germany (C.H.).

Correspondence to Dr Marek Czosnyka, Academic Neurosurgery, Box 167, Addenbrooke’s Hospital, Cambridge, UK. E-mail Mc141{at}medschl.cam.ac.uk

Background and Purpose— Mx is an index of cerebrovascular autoregulation. It is calculated as the correlation coefficient between slow spontaneous fluctuations of cerebral perfusion pressure (cerebral perfusion pressure=arterial blood pressure–intracranial pressure) and cerebral blood flow velocity. Mx can be estimated noninvasively (nMxa) with the use of a finger plethysmograph arterial blood pressure measurement instead of an invasive cerebral perfusion pressure measurement. We investigated the agreement between nMxa and the previously validated index Mx.

Methods— The study included 10 head-injured adults. Intracranial pressure was monitored with a parenchymal probe. Arterial blood pressure was monitored simultaneously with an arterial catheter and with the Finapres plethysmograph. Flow velocity in the middle cerebral artery was measured bilaterally with transcranial Doppler. Mx and nMxa were computed in both hemispheres, and asymmetry of autoregulation was calculated.

Results— Ninety-six measures of Mx and nMxa were obtained (48 for each side) in 10 patients. Mx correlated with nMxa (R=0.755, P<0.001; 95% agreement=±0.36; bias=0.01). Asymmetry in autoregulation assessed with Mx correlated significantly with asymmetry estimated with nMxa (R=0.857, P<0.0001; 95% agreement=±0.26; bias=–0.03).

Conclusions— The noninvasive index of autoregulation nMxa correlates with Mx and is sensitive enough to detect autoregulation asymmetry. nMxa is proposed as a practical tool to assess cerebral autoregulation in patients who do not require invasive monitoring.

Key Words: head injury • neuromonitoring • transcranial Doppler • autoregulation • cerebral blood flow

This article has been cited by other articles:

				J. K. Lee, K. K. Kibler, P. B. Benni, R. B. Easley, M. Czosnyka, P. Smielewski, R. C. Koehler, D. H. Shaffner, and K. M. Brady Cerebrovascular Reactivity Measured by Near-Infrared Spectroscopy Stroke, May 1, 2009; 40(5): 1820 - 1826. [Abstract] [Full Text] [PDF]