!
Intended Use
In this manual, when talking about device or equipment, the reference is to all its parts, unless otherwise
noted. Each unit alone does not produce useful results.
This medical device is intended to determinate the arterial stiffness and to record the arterial
pressure wave, by means of the “applanation tonometry”, for diagnostic purposes. It must be used by
qualified medical / paramedical personnel, familiar with the “applanation tonometry” method, in
medical environment or research centers.
The primary functions are capture, display and storage of the arterial tonometric
signal for later calculation of the related parameters including Pulse Wave Velocity -
PWV, that defines the arterial stiffness. This instrument is based on the applanation
tonometry principle. The user places the sensor on the skin, where the artery pulse is
found, with a moderate pressure that slightly compresses the artery (applanation
tonometry): in such way, a balance of the circumferential forces inside the vessel is
obtained and the sensor records the pressure inside the compressed artery.
Intermediate layers between sensor and vessel, with their thickness and rigidity, that
vary for each individual, influence the pressure measured by the sensor in a not, a
priori, quantifiable manner. For this reason it is necessary to calibrate tonometric
signals using the systolic and diastolic pressures obtained from an external
sphygmomanometer (supplied by the operator). The calibration process is based on
the assumption that diastolic and mean pressure substantially don’t change along the
arterial tree.
The pulse wave velocity is defined as the
propagation velocity of the pressure wave
(not of the blood) from the center to the
periphery and is therefore obtained by
dividing the distance between two examined
points (for example Carotid and Femoral) by
the related sphygmic wave transit time
(DeltaT).
This propagation time can be assessed in two different ways (I or II):
I. Using the
wEc1
unit together with the
wTn1
unit, first for Carotid (R-cW) and then for the peripheral
artery (e.g. the Femoral Artery in figure, R-fW ) , to measure the delay time between the R peak of the
ECG wave and the “foot” of the tonometric waves, time A and B, and then the difference between them,
DeltaT.
II. Using two
wTn1
units to contemporarily capture two tonometric signals, one of the Carotid and the
other of the selected peripheral Artery, to obtain the time interval DeltaT between the two waves’ “feet”.
⚠
The ECG lead captured must only be used for PWV estimation and must never be used for any kind
of diagnosis on the patient!
!
3
User Manual
PulsePen
- V. 4.6
