Mietke GAV 2.0
- Instruction for use
- Technical description
GAV 2.0 is a valve made from titanium. It consists of a ball-cone unit and a gravitational unit. Thus a physiological intraventricular pressure (IVP) can be reached in any body position. In the proximal part of the GAV 2.0, micro spiral spring (1) enables the opening pressure of the ball-cone unit. The gravitational unit in the distal part of the valve consists of a tantalum ball (2) which defines the opening pressure of this unit, and a sapphire ball (3) which enables its precise closure. Coding (4) permits the identification of pressure levels in an X-ray.
- GAV 2.0 in horizontal position
In the horizontal position, the gravitational unit is always open and does not present any resistance. For that reason, the GAV 2.0 opening pressure in this position is only defined by the ball-cone unit. (A) shows the ball-cone unit in closed status. If the patient’s intraventricular pressure (IVP) exceeds the opening pressure of the micro spiral spring, the ball from the cone, thus opening a gap for drainage (B).
- GAV 2.0 in vertical position
When the patient moves into an upright position, the gravitational unit is activated and the opening pressure of the GAV 2.0 is significantly increased (A). In addition to the opening pressure of the ball-cone unit, the weight of the tantalum ball (opening pressure of the gravitational unit) has to be exceeded. Drainage is only possible once the sum of intraventricular pressure (IVP) and hydrostatic pressure is greater than the opening pressure of both units (B).
Mietke proGAV 2.0
Has 3 components
Reservoir
- Can use a traditional reservoir instead with an in line connector if you cannot find one
Differential pressure unit
- Fixed
- Variable
- Adjustable differential pressure unit
- 0-20cm H₂O
Gravitational unit valve
Fixed
- 20cmH₂O
- Less than 5 yrs old or more than 65 yrs old
- 25cmH₂O
- Between 5 yrs old and 65 yrs old
Opening pressure for vertical posture | Coding of gravitational unit |
10 cmH₂O | Small, no ring |
15 cmH₂O | Large, no ring |
20 cmH₂O | Large, 1 ring |
25 cmH₂O | Large, 2 rings |
30 cmH₂O | Large, 3 rings |
35 cmH₂O | Large, 4 rings |
Variable: Blue series
Instruction for use:
Technical description
- The proGAV 2.0 is a valve made from titanium.
- It consists of an
- Adjustable differential pressure unit AND
- The adjustable differential pressure unit consists of a stable titanium housing in which a tried and tested ball cone valve (1) is integrated in the proximal section.
- A bow spring (2) determines the opening pressure of this unit.
- The pretension of the spring, and therefore the valve opening pressure, can be adjusted through the skin using a revolving rotor on a bearing (3).
- Gravitational unit
- Major components in the gravitational unit are a tantalum ball (4), which defines the opening pressure for this valve depending on the body position and a sapphire ball (5), which ensures precise closure.
Horizontal position
In the horizontal position, the gravitational unit is always open and does not present any resistance.
Consequently, the opening pressure of the proGAV 2.0 in the horizontal body position is characterized 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 possible. In fig. 3b, the adjustable differential pressure unit is shown in the open state.
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 position, in that moment the gravitational unit closes (fig. 4a). Now, additionally to the opening pressure of the adjustable DP-unit, the weight of the tantalum ball has to be exceeded (opening pressure of the gravitational unit), thus the opening pressure of the proGAV 2.0 is significantly 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).
During physical activity which is associated with vibrations (for example jogging) the opening pressure of the proGAV 2.0 can decrease temporarily by 25% to 35% according to laboratory results. This affects both the individual valve and the combination with a gravitational 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.
Reading the pressure setting from an X-ray image
Valve test
- Preoperative valve test
- The most careful way of filling the valve is by aspiration through a sterile single-use syringe attached to the distal end of the catheter. The distal end of the valve is connected and immersed in a sterile physiological saline solution. The valve is patent if saline solution can be extracted (fig. 15).
Contamination in the solution used for testing can impair the product‘s performance.
Pressurisation by the single-use syringe should be avoided both at the proximal and the distal end (fig. 16).
- Postoperative valve test
- The proGAV 2.0 has been constructed as a reliably functioning unit without pump or test function. The valve test can be performed by flushing, pressure measurement or pumping.
Mode of operation
Recommendation
Features and benefits
Feature | Benefit |
Soft Touch mechanism | Easy and comfortable adjustment |
proGAV 2.0 instruments | Increases patient comfort |
“Active-Lock” mechanism 3-Tesla MR safe | No unintended readjustments by external magnetic fields |
Gravitational unit | Proven overdrainage protection |
Design and function of sensor reservoir
Membrane:
- Injection of medication
- Fluid removal
- Careful pumping
Types of measurement
- Three types of measurements takes 44 measurements per seconds
Made with Bullet