Please use this identifier to cite or link to this item: http://ahro.austin.org.au/austinjspui/handle/1/9154
Title: Systematic errors in estimating mean blood pressure from finger blood pressure measurements.
Authors: O'Callaghan, Christopher J;Straznicky, N E;Komersova, K;Louis, William J
Affiliation: Department of Medicine, University of Melbourne, Austin and Repatriation Medical Centre, Heidelberg, Australia
cjo1@le.ac.uk
Issue Date: 1-Nov-1998
Citation: Blood Pressure; 7(5-6): 277-81
Abstract: The mean blood pressure (BP) can be accurately estimated from indirect measurements of brachial artery pressure, i.e. mean BP = diastolic BP + 1/3 pulse pressure. Although this equation has been used as a surrogate of mean systemic pressure, it is unknown whether this approximation can be validly applied to distal vascular beds. Therefore we determined the accuracy of this method as an estimate of the mean pressure in distal arteries by measuring finger BP with the Finapres device in 16 normotensive and 12 hypertensive subjects. The "calculated" and measured values of mean BP were compared when subjects were resting and during manoeuvres which aimed to alter the shape of the pulse waveform. Although closely correlated with the measured value, the "calculated" resting mean BP was systematically greater (+2.7+/-0.7 mm Hg, p<0.001). Additionally, the rise in the mean pressure produced by infusion of phenylephrine, an alpha1-adrenoceptor stimulant (16.0+/-1.5 mm Hg) was underestimated by the calculation (13.1+/-1.5 mm Hg, p<0.05). Of even greater concern was that calculating the mean pressure during infusion of isoprenaline (a beta-adrenergic stimulant) suggested the mean pressure had increased by 5.8+/-1.6 mm Hg when it had actually fallen (-2.1+/-2.4 mm Hg, p<0.001 vs. the measured value). Thus, calculating the mean BP from Finapres measurements roughly approximates the measured value when subjects are at rest. However, this estimation becomes inaccurate when pulse wave dimensions are altered, and is probably unsuitable for assessing the acute effects of vasoactive drugs, in particular vasodilators, on BP.
Internal ID Number: 10321439
URI: http://ahro.austin.org.au/austinjspui/handle/1/9154
URL: http://www.ncbi.nlm.nih.gov/pubmed/10321439
Type: Journal Article
Subjects: Adrenergic beta-Agonists.pharmacology
Arm.blood supply
Blood Pressure Determination.methods
Diagnostic Errors
Female
Fingers.blood supply
Humans
Isoproterenol.pharmacology
Male
Middle Aged
Phenylephrine.pharmacology
Reference Values
Regional Blood Flow.drug effects.physiology
Reproducibility of Results
Vasoconstrictor Agents.pharmacology
Appears in Collections:Journal articles

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