Cerebrovascular regulation during transient hypotension and hypertension in humans

Hdl Handle:
http://hdl.handle.net/10149/218332
Title:
Cerebrovascular regulation during transient hypotension and hypertension in humans
Authors:
Tzeng, Y-C. (YuChieh); Willie, C. K. (Chris); Atkinson, G. (Greg); Lucas, S. J. E. (Samuel); Wong, A. (Aaron); Ainslie, P. N. (Philip)
Citation:
Tzeng, Y.C., Willie, C.K., Atkinson, G., Lucas, S.J., Wong, A., and Ainslie, P.N. (2010) 'Cerebrovascular regulation during transient hypotension and hypertension in humans', Hypertension, 56(2), pp.268-273.
Publisher:
Lippincott, Williams & Wilkins
Journal:
Hypertension
Issue Date:
Aug-2010
URI:
http://hdl.handle.net/10149/218332
DOI:
10.1161/HYPERTENSIONAHA.110.152066
PubMed ID:
20547971
Additional Links:
http://hyper.ahajournals.org/content/56/2/268
Abstract:
The cerebrovasculature dilates or constricts in response to acute blood pressure changes to stabilize cerebral blood flow across a range of blood pressures. It is unclear, however, whether such dynamic cerebral autoregulation (dCA) is equally effective in responding to falling versus rising blood pressure. In this study we applied a pharmacological approach to evaluate dCA gain to transient hypotension and hypertension and compared this method with 2 established indices of dCA that do not explicitly differentiate between dCA efficacy and falling versus rising blood pressure. Middle cerebral arterial velocity and blood pressure recordings were made in 26 healthy volunteers randomized to 2 protocols. In 10 subjects, dCA gain to transient hypotension induced with intravenous nitroprusside was compared with dCA gain to transient hypertension induced with intravenous phenylephrine. In 16 subjects, dCA gain to transient hypotension induced with intravenous nitroprusside was compared with the rate of regulation and autoregulatory index derived from transient hypotension induced with the thigh cuff deflation technique. dCA gain to transient hypotension induced with intravenous nitroprusside was unrelated to dCA gain to transient hypertension induced with intravenous phenylephrine (r=0.06; P=0.87) and was consistently greater than dCA gain to transient hypertension induced with intravenous phenylephrine (0.57+/-0.16 versus 0.31+/-0.20 cm/s per millimeter of mercury; P<0.01). However, dCA gain to transient hypotension induced with intravenous nitroprusside was inversely related to the rate of regulation (r=-0.52; P=0.037) and autoregulatory index (r=-0.66; P=0.005). These data indicate that, under our laboratory conditions, dCA appears to be inherently nonlinear with disparate efficacy against rising and falling blood pressure, and dCA gain derived from pharmacologically induced transient hypotension correlates with established nonpharmacological indices of dCA.
Type:
Article
Language:
en
Keywords:
blood flow velocity; blood pressure; cerebral arteries; hemodynamics; brain circulation; transcranial Doppler
ISSN:
0194-911X
EISSN:
1524-4563
Rights:
Subject to restrictions author can archive publisher's version/PDF. For full details see http://www.sherpa.ac.uk/romeo/ [Accessed 12/04/2012].
Citation Count:
8 [Scopus, 12/04/2012]

Full metadata record

DC FieldValue Language
dc.contributor.authorTzeng, Y-C. (YuChieh)en_GB
dc.contributor.authorWillie, C. K. (Chris)en_GB
dc.contributor.authorAtkinson, G. (Greg)en_GB
dc.contributor.authorLucas, S. J. E. (Samuel)en_GB
dc.contributor.authorWong, A. (Aaron)en_GB
dc.contributor.authorAinslie, P. N. (Philip)en_GB
dc.date.accessioned2012-04-12T14:39:51Z-
dc.date.available2012-04-12T14:39:51Z-
dc.date.issued2010-08-
dc.identifier.citationHypertension; 56 (2): 268-273en_GB
dc.identifier.issn0194-911X-
dc.identifier.pmid20547971-
dc.identifier.doi10.1161/HYPERTENSIONAHA.110.152066-
dc.identifier.urihttp://hdl.handle.net/10149/218332-
dc.description.abstractThe cerebrovasculature dilates or constricts in response to acute blood pressure changes to stabilize cerebral blood flow across a range of blood pressures. It is unclear, however, whether such dynamic cerebral autoregulation (dCA) is equally effective in responding to falling versus rising blood pressure. In this study we applied a pharmacological approach to evaluate dCA gain to transient hypotension and hypertension and compared this method with 2 established indices of dCA that do not explicitly differentiate between dCA efficacy and falling versus rising blood pressure. Middle cerebral arterial velocity and blood pressure recordings were made in 26 healthy volunteers randomized to 2 protocols. In 10 subjects, dCA gain to transient hypotension induced with intravenous nitroprusside was compared with dCA gain to transient hypertension induced with intravenous phenylephrine. In 16 subjects, dCA gain to transient hypotension induced with intravenous nitroprusside was compared with the rate of regulation and autoregulatory index derived from transient hypotension induced with the thigh cuff deflation technique. dCA gain to transient hypotension induced with intravenous nitroprusside was unrelated to dCA gain to transient hypertension induced with intravenous phenylephrine (r=0.06; P=0.87) and was consistently greater than dCA gain to transient hypertension induced with intravenous phenylephrine (0.57+/-0.16 versus 0.31+/-0.20 cm/s per millimeter of mercury; P<0.01). However, dCA gain to transient hypotension induced with intravenous nitroprusside was inversely related to the rate of regulation (r=-0.52; P=0.037) and autoregulatory index (r=-0.66; P=0.005). These data indicate that, under our laboratory conditions, dCA appears to be inherently nonlinear with disparate efficacy against rising and falling blood pressure, and dCA gain derived from pharmacologically induced transient hypotension correlates with established nonpharmacological indices of dCA.en_GB
dc.language.isoenen
dc.publisherLippincott, Williams & Wilkinsen_GB
dc.relation.urlhttp://hyper.ahajournals.org/content/56/2/268en_GB
dc.rightsSubject to restrictions author can archive publisher's version/PDF. For full details see http://www.sherpa.ac.uk/romeo/ [Accessed 12/04/2012].en_GB
dc.subjectblood flow velocityen_GB
dc.subjectblood pressureen_GB
dc.subjectcerebral arteriesen_GB
dc.subjecthemodynamicsen_GB
dc.subjectbrain circulationen_GB
dc.subjecttranscranial Doppleren_GB
dc.titleCerebrovascular regulation during transient hypotension and hypertension in humansen
dc.typeArticleen
dc.identifier.eissn1524-4563-
dc.identifier.journalHypertensionen_GB
ref.citationcount8 [Scopus, 12/04/2012]en_GB
or.citation.harvardTzeng, Y.C., Willie, C.K., Atkinson, G., Lucas, S.J., Wong, A., and Ainslie, P.N. (2010) 'Cerebrovascular regulation during transient hypotension and hypertension in humans', Hypertension, 56(2), pp.268-273.en_GB

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