Physics Background - MIETHKE proGAV 2.0 Instrucciones De Manejo

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PhysIcs background

The intraventricular pressure is positive in a
healthy human in a horizontal position. To ad-
just this pressure through shunt drainage, one
has to choose the appropriate pressure range,
taking into account the abdominal cavity pres-
sure. The resulting IVP is the sum of the shunt
opening pressure and the abdominal cavity
pressure (fig. 6).
horizontal: IVP = P
IVP = P
vertical:
IVP Intraventricular pressure
P Opening pressure in horizontal position
l
(adjustable DP-unit only)
P Opening pressure in vertical position
S
(adjustable DP-unit + gravitational unit)
P Pressure in the abdominal cavity
B
P Hydrostatic pressure
h
IVP
Fig. 6: Calculating the intraventricular pressure for horizontal and vertical body position
20
+ P
l B
- P - P
h S B
The ventricular pressure in a healthy human in
a vertical position becomes slightly negative.
To maintain this pressure by means of shunt
drainage, the shunt opening pressure has to be
significantly higher so that the shunt can com-
pensate the hydrostatic pressure minus the
sum of the abdominal cavity pressure and the
slightly negative intraventricular pressure.
P
l
P
B
IVP
P
S
P
B