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PHYSIO-PORT / PHYSIO-PORT AS
A8136 Revision A
Application, Safety Information
The inflation measurement method is a novel method
based on the "Inflation Measurement Technology
(IMT)" developed by PAR Medizintechnik. With this
innovative technique, the cuff is inflated to a pressure
just above the expected systolic value. Once the systolic
value is determined, the cuff can immediately and
quickly be deflated. The measurement typically takes
only approx. 20 seconds. (see Fig. 1-2)
If disturbances occur during measurements with the in-
flation measurement method, which may be due to mo-
tion artifacts, for example, the PHYSIO-PORT devices
will automatically switch to the deflation measurement
method and complete the blood pressure measurement.
Fig. 1-2 Waveform representing the pressure in the cuff
during a measurement using the inflation
measurement method: systolic pressure at 125
mmHg, diastolic pressure at 83 mmHg
With both methods, a pressure transducer measures the
cuff pressure as well as the superimposed pressure pulsa-
tions. During blood pressure measurements the cuff must
be at heart level. If this is not ensured, the hydrostatic
pressure of the liquid column in the blood vessels will
lead to incorrect results. (Each 10 cm difference result in
a pressure deviation of 8.0 mmHg.)
When the patient is sitting or standing during measure-
ments the cuff is automatically at the correct level.
The Pulse Wave Analysis
Electively, the variant PHYSIO-PORT AS (
A
rterial
S
tiffness) can conduct a pulse wave analysis following a
non-invasive blood pressure measurement.
If elected, the pulse wave analysis is performed right after
one of the two blood pressure measurement methods. For
this, the measured mean arterial pressure level (MAD) is
set in the cuff and the pulses in the cuff are recorded for
a fixed period of time (see Fig. 1-3). Disturbances are
removed from the recorded pulses. From the usable
pulses, the pulse that is located centrally at the heart is
reconstructed non-invasively to determine the central
blood pressure and the pulse wave velocity. Both
parameters can be used by the physician to estimate the
patient-specific state of the vessels.
Fig. 1-3 Waveform representing the pressure in the cuff
during a measurement using the inflation
measurement method with subsequent pulse
wave analysis
1.2 Functional Description
The PHYSIO-PORT devices accommodate the blood
pressure measuring system and a microprocessor for
system control and data processing.
A second microprocessor with a second pressure trans-
ducer and a second valve are provided for control of the
technical safety.
The devices are powered by two AA size batteries (either
rechargeable NiMH batteries or alkaline batteries).
The variant PHYSIO-PORT AS holds an additional high-
performance circuit board (PWA module) which is
integrated in the basic version PHYSIO-PORT in order to
perform the pulse wave analysis. This board has its own
microprocessor and works only on command from the
PHYSIO-PORT main system whereby the additional
function has no influence on safety-relevant features of
the basic version.
