MIETHKE proGAV 2.0 XABO Instrucciones De Manejo página 24

| INSTRUCTIONS FOR USE
contained in the catheter represent only a frac-
tion of the therapeutic dose of these antibiotics.
The proGAV 2.0 XABO is a posture-depen-
dent hydrocephalus valve system. The opening
pressure of the proGAV 2.0 XABO is composed
of the opening pressures of the adjustable dif-
ferential pressure unit and the gravitational unit.
In the horizontal body position, the gravitational
unit is always open and does not present any
resistance (Fig. 2).
Fig. 2: The gravitational unit in the horizontal body posi-
tion
The opening pressure of the proGAV 2.0 XABO
in the horizontal body position is thus deter-
mined by the adjustable differential pressure
unit. The basic operating principle of the differ-
ential pressure unit is shown in Fig. 3 a) and b).
Fig. 3: The adjustable differential pressure unit in the
horizontal body position
a) closed b) open
In Fig. 3 a), the differential pressure unit is
closed hence, shunting is not possible.
24
If the patient's intraventricular pressure (IVP)
exceeds the spring force of the torsion spring,
which otherwise keeps the differential pressure
unit closed, the sealing ball moves out of the
cone, leaving a gap for shunting of CSF (Fig. 3
b).
As soon as the patient sits or stands up, the
gravitational unit immediately closes (Fig. 4 a).
The opening pressure of the proGAV 2.0 XABO
is thus increased significantly, because now the
weight of the tantalum ball (opening pressure
of the gravitational unit) must be overcome in
addition to the opening pressure of the differ-
ential pressure unit. Shunting is only possible
again when the sum of IVP and hydrostatic suc-
tion is greater than the opening pressure of both
units (Fig. 4 b).
For individual adaptation of the opening pres-
sure to the patient, an opening pressure
between 0 and 20 cmH O can be selected for
the adjustable differential pressure unit.
Fig. 4: Gravitational unit in the vertical body position
a) closed b) open
proGAV ® 2.0 XABO ®