Function Of The Valve - MIETHKE proGAV 2.0 Instrucciones De Manejo

functIon of the valve

The opening pressure of the proGAV 2.0 is de-
fi ned by the opening pressure of the adjustable
dP-unit and the opening pressure of the gravi-
tational unit.
Horizontal position
when the patient is lying down, the gravitatio-
nal unit is always open and therefore does not
present any resistance to the fl uid fl ow. (fi g. 3).
Fig. 3: Gravitational unit in horizontal position
hence, the opening pressure of the proGAV
2.0 is defi ned by the adjustable dP-unit. The
operational principle of the adjustable dP-unit
is illustrated in fi gures 3 and 4.
In fi g. 4a, the ball-cone valve is closed. The
drainage is blocked. In fi g. 4b, the adjustable
dP-unit is shown in the open condition. The
patient's IVP is increased and the spring force,
which otherwise keeps closed the ball-cone
valve, is overcome. The closing ball moves out
of the cone and a gap opens to allow drainage.
a)
b)
Fig. 4: Adjustable DP-unit
a) closed b) open
INSTrUcTIONS fOr USe |
Vertical position
when the patient moves into an upright positi-
on, in that moment the gravitational unit closes
(fi g. 5a). Now, additionally to the opening pres-
sure of the adjustable dP-unit, the weight of
the tantalum ball has to be exceeded (opening
pressure of the gravitational unit), thus the ope-
ning 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 (fi g. 5b).
a) b)
Fig. 5: Gravitational unit in vertical position
a) closed, b) open
Note: during physical activity which is asso-
ciated with shocks (e.g.: running), laboratory
results have shown that the proGAV 2.0's ope-
ning pressure can decrease temporarily around
25% to 35%.
This concerns the single valve aswell as the
combination with the gravitational unit. Princi-
pallly, the reliability of the proGAV 2.0 is pre-
served. Once physical activity is stopped the
original opening pressure will be re-established.
GB
19