Introduction
16
EasyOne Pro™ / EasyOne Pro™ LAB
EasyOne Pro™
consists of a compact main unit and a hand-held flow
sensor
S
with removable DLCO valve unit
Q
. The hand-held sensor is
electrically connected to the device. For DLCO tests, a gas supply tube
P
delivers gas to the DLCO valve. The sensor measures flow velocity, volume
and molar mass of the gases that the patient inhales and exhales.
The mains connector
A
connects the device to line power. The gas cylinder
T
supplies the medical gas mixture that is required to perform DLCO tests
(normally 0.3% CO, 10% He, 21% O
2
in N
2
).
A temperature and humidity sensor
H
measures the temperature and
humidity in the examination room.
The device contains an industrial standard PC
E
(
Windows XP embedded
)
that performs data acquisition, data analysis and storage of test results.
The user interface for display and control consists of a flat panel display
with touch screen
N
. If required a keyboard and/or a mouse can be
connected to the PC. A pneumatic system
J
delivers gas to the patient,
allows flushing of the DLCO gas delivery hose and draws gas samples from
the patient's inspiratory and expiratory breath. The side stream flow used
for gas analysis is driven by a pump
I
. CO gas is analyzed by a sensor based
on infrared absorption
L
. A molar mass sensor
M
based on ultrasound
transit time measurement determines the helium content of the respired air.
The oxygen supply unit
V
required by the
EasyOne Pro™ LAB
version is
located on the left side of the device.
Note
EasyOne Pro™
includes the
Touch-It Virtual Keyboard
developped
by Chessware SA.
1.11
EasyOne Pro™
Flow Sensor Design and Operation
The ultrasound flow sensor measures the transit time to determine flow
velocity, volume and molar mass of the gas (molecular weight x
concentration). The illustration below explains the measuring principle: two
ultrasound sensors emit very short ultrasound pulses that travel along the
transmission path to the opposite ultrasound transducer. Measuring the
transit times allows the flow velocity to be determined very accurately and
independently of temperature, humidity and molar mass of the gas. Since
the measuring principle is based on a digital measurement technique, the
sensor requires only one single calibration. The sensor calibration does not
change during the sensor's lifetime.