title: Do the Finapres and Colin radial artery tonometer measure the same blood pressure changes following deflation of thigh cuffs?
abstract: The objective of this work was to determine if systematic differences exist between blood pressure time series measured by two non-invasive techniques. Cerebral blood flow autoregulation is often measured while a change in blood pressure is induced by deflation of thigh cuffs. To interpret the result a continuous measurement of arterial blood pressure is required. The Finapres is a non-invasive blood pressure monitor that is often used when assessing autoregulation but there is uncertainty about its reliability. A more recent device, the Colin tonometer, uses radial artery tonometry, which may prove to be a more reliable non-invasive method of obtaining a blood pressure waveform. Twenty healthy volunteers were recruited; blood pressure trends following cuff deflation were measured simultaneously with a Finapres and a Colin tonometer. A significant difference was found between the blood pressure waveforms measured with the two devices. The most striking difference was a slower recovery time measured with the Finapres (Wilcoxon signed rank test P < 0.001). Peripheral vasoaction may be distorting the measurement of blood pressure by the Finapres. This would account for the difference that exists between the techniques. Comparison with a direct arterial line would confirm which non-invasive measurement is more accurate.
mesh_terms: D001794:Blood Pressure / Q000502:physiology*; D001795:Blood Pressure Determination / Q000379:methods* / Q000592:standards; D015924:Blood Pressure Monitors; D002560:Cerebrovascular Circulation / Q000502:physiology*; D006706:Homeostasis / Q000502:physiology; D006801:Humans; D011673:Pulsatile Flow / Q000502:physiology; D017534:Radial Artery / Q000502:physiology*; D015203:Reproducibility of Results; D013848:Thigh / Q000098:blood supply*