Comparative study of Finapres devices

Devices based on the arterial volume clamping technique, such as the Finapres, Portapres or Finometer, have become the methods of choice in studies requiring continuous noninvasive recordings of arterial blood pressure (BP). Most validation studies have used intravascular BP measurements in the radial artery as a reference. We tested the hypothesis that the simultaneous use of two Finapresses in different combinations of fingers and hands would not lead to significant differences.

Two Finapresses of the same model were used. BP was measured using four combinations of ipsilateral and contralateral middle and ring fingers and two Finapresses on 11 healthy individuals. Differences between the two devices were assessed at rest by the agreement between systolic, mean and diastolic values, pulse bandwidth, frequency response, magnitude squared coherence and drift. BP response to the Valsalva manoeuvre was used for dynamic comparisons.

The two Finapresses showed significant differences for systolic (P=0.010), mean (P=0.008) and diastolic (P=0.021) pressures (two-way analysis of variance). No significant differences were found for drift, bandwidth or the Valsalva manoeuvre. Spectral and coherence analysis showed a linear frequency response to ∼13 Hz.

Different Finapres devices might show differences between the systolic, mean and diastolic BP at rest, but there is excellent agreement between dynamic indices. The response bandwidth is adequate to register the BP waveform with good accuracy, thus supporting applications in which waveform-dependent indices are extracted. Further studies are required in patients with different pathologies, including those with peripheral circulatory disorders.