MIETHKE proGAV 2.0 Instrucciones De Manejo página 17

proGAV ® 2.0
Horizontal position
In the horizontal position, the gravitational unit
is always open and does not present any resis-
tance.
Fig. 2: Gravitational unit in horizontal body position
Consequently, the opening pressure of the pro-
GAV 2.0 in the horizontal body position is char-
acterised by the adjustable differential pressure
unit. The principal working method used by the
adjustable differential pressure unit is shown in
fig. 3a and b.
In fig. 3a it is closed so that no drainage is pos-
sible. In fig. 3b, the adjustable differential pres-
sure unit is shown in the open state.
Fig. 3: Adjustable differential pressure unit in horizontal
body position
a) closed b) open
INSTRUCTIONS FOR USE | EN
The intraventricular pressure (IVP) of the patient
is increased and the spring force which would
otherwise keep the differential pressure unit
closed is overcome. Now, the sealing ball
moves out of the cone and a gap is sealing for
liquor drainage.
Vertical position
When the patient moves into an upright posi-
tion, in that moment the gravitational unit closes
(fig. 4a). Now, additionally to the opening pres-
sure of the adjustable DP-unit, the weight of
the tantalum ball has to be exceeded (open-
ing pressure of the gravitational unit), thus the
opening pressure of the proGAV 2.0 is signifi
cantly increased. Only when the sum of the
IVP and the hydrostatic pressure exceeds the
opening pressure of the proGAV 2.0, drainage
will be possible again (fig. 4b).
Fig. 4: Gravitational unit in vertical body position
a) closed b) open
During physical activity which is associated with
vibrations (for example jogging) the opening
pressure of the proGAV 2.0 can decrease tem-
porarily by 25 % to 35 % according to labo-
ratory results. This a ects both the individual
valve and the combination with a gravita-
tional unit. As a basic principle, functionality is
retained. At the end of physical activity, the
opening pressure returns to its original level and
remains stable.
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