Selection Of Appropriate Pressure Level - MIETHKE M.blue Mode D'emploi

M.blue
®
Consequently, the opening pressure of M.blue
in the horizontal position is characterised by the
fixed differential pressure unit pre selected at
implantation to be either 0, 5 or 10 cm H
is not adjustable. The main operation method
used by the adjustable differential pressure unit
is shown in Fig. 2a and b.
Fig. 2: Operation of the differential pressure unit
a) closed b) open
In fig. 2a the valve is closed, hence drainage is
not possible.
If the patient's intraventricular pressure (IVP)
exceeds the spring force of the micro-coil
spring, the sealing ball moves out of the cone,
leaving a gap for CSF drainage (fig. 2b).
Vertical position
As the patients body moves from prone to
vertical, the gravitational unit closes the dis-
charge channel in the proximal part of the valve
(Fig. 3a). Thus, the opening pressure of M.blue
is increased in the upright position, because
now the weight of the tantalum weight (opening
pressure of the gravitational unit) must be over-
come in addition to the opening pressure of the
differential pressure unit. Drainage is only pos-
sible once the sum of IVP and hydrostatic suc-
tion is greater than the opening pressure of both
units (fig. 3b). For individual adaptation of the
opening pressure to the patient, a valve open-
ing pressure between 0 and 40 cm H
selected for the adjustable gravitational unit.
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Fig. 3:
a) closed b) open
During physical activity which is associated with
shock (e.g. jogging) the opening pressure of
M.blue may decrease temporarily according to
laboratory results. Generally however, function-
ality is retained. At the end of physical activity,
the opening pressure returns to its original level
and remains stable.
SELECTION OF APPROPRIATE
PRESSURE LEVEL
Horizontal position
In the lying position, the gravitational unit has
no influence on the valve opening pressure. In
this position, the valve opening pressure is thus
determined exclusively by the differential pres-
sure unit. In this case, the pressure level should
be set in accordance with the clinical picture
and indications. By default, a differential pres-
sure unit with an opening pressure of 5 cmH
is recommended.
Vertical position
The M.blue opening pressure for the ver-
tical body position is calculated from the
sum of the opening pressure in the differen-
tial pressure unit and the adjustable gravita-
tional unit. Patient height, activity level and
potentially increased abdominal pressure (obe-
sity) should be taken into account in select-
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ing the opening pressure for the gravitational
unit (see pressure level recommendations at
https://www.miethke.com/downloads/). This is
a non-binding recommendation for the attend-
ing physician. According to his diagnosis, the
physician decides each case independently,
without instructions and individually.
INSTRUCTIONS FOR USE | EN
Gravitational unit in vertical body position
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