VP shunt systems are programmed proGAV
Şekil-1. ProGAV mechanism
MIETHKE proGAV position is a dependent valve.The opening pressure of valve changes according to patients position otomotically.When a proGAV put into practice;pressures are conditioned of the patients such as horizantal and vertical position.
Şekil-2 Gravitasyonel ünit
The pressure of the body’s of patient working pressure is determined by the adjustable unit of valves.Gravitational ünit has no effect on the working pressure.Woking pressure of the valve is adjusted while after the determinig of patients suitable values between the 0 and 20 cmH2O(21 steps).
If the patient is horizantal position,the gravitional unit sopn all the time,it does not disrupt to flow of BOS.(figure 2)In the figure of 3 and 4 shows the function of adjustable unit.
Şekil-3 Adjustable unit and valve-close
Şekil-4 Adjustable unit and valve-open
When the patient is afoot,gravitional unit is closed.For this reason pressure of the proGAV get by the high functional grade and happens the BOS dreinage.(figure 5)the total of intraventicüler pres and hydrostatic pres drive through the second step of proGAV,dreinage starts reagain.(figure6).In the vertical position the working pressure of proGAV equals the total pressure of adjustable unit and gravitional unit.
Gravitional unit Şekil-5 close Şekil-6 open
Value of the pressure of proGAV
|Standard||Smart unit||Gravitional unit|
|Above the lenght of 1.60 and active patients until 60 years old||0 - 20 cm H2O||25 cm H2O|
|Until the 5 years of child and above 60 years old patients||0 -20 cm H2O||20 cm H2O|