Infusion pumps are used in an infusion therapy, where the standard gravity infusion is not precise enough or can't be used because of space limitations. They have a mechanical or electrical drive which guarantees the permanent supply of medication.
The pump is connected to a port cannula with an infusion line, which for its part makes the connection to the port and thus to the patient's vascular system (vein or artery).
Also see description: Ports and accessories.
Electrical Infusion Pumps
Within the electrical infusion pumps are two versions.
A syringe (commonly with a volume of 20ml or 50 ml) will be fixed in the pump and the piston will be pushed forward with the selected flowrate.
Because of their dimensions these pumps are not used for ambulatory but for stationary applications.
The pump consists of two elements:
The electrical control unit and the medication reservoir.
After the medication reservoir is filled, it will be connected with the control unit.
Volumetric pumps works on the basis of the peristaltic system. Pressure is exerted on the infusion line that is coming from the reservoir. This alternate high- and low-pressure conditions in the infusion line, make it possible to "suck out" the medication reservoir until it is empty.
These pumps are available in different sizes. The smaller versions are used for ambulatory applications, where patients can carry them permanently thanks to their small dimensions and low weight.
With all of these pumps the flowrate is individually selectable (normally with 0,1 ml/h increments) and different alarm functions (of audio and visual kind) are existing.
The disadvantage is the high cost that are in the region of 1000 Euro.
Therefore much cheaper mechanical pumps are often used for ambulatory applications.
The product range of medfein consists of:
Infusion Syringe Pump AJ 5803
Ambulatory Infusion Pump AJ 5806
The AJ 5806 pump combines the advantages of an electric pump (high precision and selectable flowrates) with the price of a mechanical pump.
To reach this goal certain functions had been simplified (the flowrate selection is limited to 7 rates).
We consider this pump as a price sensitive alternative to the mechanical disposable pumps that can only be used one time.
Because the control unit of the AJ 5806 is reusable, remarkable cost savings can be realized already in short term.
Mechanical Infusion Pumps
An mechanical infusion pump is a fluid reservoir (50 - 200 ml) which guarantees the permanent supply of medication by a mechanical drive.
The pumps available on the market comprise a silicon hose, which is filled with the medication in question and thus adopts the shape of a balloon.
The entire equipment is in a protective cover made of transparent plastic. These pumps are generally called balloon pumps.
Due to the balloon's tendency to compress again, a pressure which presses the fluid out of the balloon through the infusion line is exercised.
The flowrate is limited by a capillary tube and can' t be changed; that means each pump has only one flow rate.
Due to the material, the balloon pump described above cannot guarantee a constant pressure for the whole infusion period. The tolerance is ± 10 - 15%.
However, this tolerance figure refers to the whole infusion period.
Temporary pressure peaks with deviations of about 20% are also possible.
As the capillary tube which limits the flow rate is not in a position to compensate the pressure peaks, this also means a faulty supply by about 20%.
All mechanical infusion pumps are disposable pumps, that means they can be used only one time and have to be disposed after use.