INSULIN INJECTION TECHNIQUES: CONTINUOUS SUBCUTANEOUS AND IMPLANTABLE PUMPS
INSULIN INJECTION TECHNIQUES: CONTINUOUS SUBCUTANEOUS AND IMPLANTABLE PUMPS
Continuous subcutaneous insulin infusion pumpsThe new device that everyone asks about is the continuous subcutaneous insulin infusion (CSII) pump. This is the first step towards the portable artificial pancreas. Put simply, the pancreas needs to be able to do two things as tar as the diabetic is concerned. First, to sense the blood glucose level. Second, to increase or decrease insulin output in response to that glucose vel. People involved in diabetes research in Japan, and elsewhere, have succeeded in making a fine needle sensor that can be inserted subcutaneously to register the concentration of blood glucose in tiny blood vessels (capillaries). This device can then activate an insulin pump to release the correct amount of insulin. As yet this is not ready for widespread use. There are teething troubles with the glucose sensing part of the artificial pancreas. The insulin infusing part is, though, already on the market.Insulin infusion pumps slowly and continuously push down the plunger of a syringe or vial of insulin at a preset rate. Extra squirts of insulin can be given through a button on the pump, whenever necessary Fast-acting insulin is always used. The pump is set up so that it delivers a background or basal infusion over a twenty-four hour period, then at each meal and sometimes at snack times the wearer presses the button to give the correct amount of insulin to cope with that particular meal. Sally, for example, is on abase rate of twelve units per twenty-four hours (or 0.5 units per hour). She has four units before breakfast, four before lunch and six before her evening meal, which is the largest of the day.
Implantable pumps Heart pacemakers – whose technology is being used to develop CSII pumps – are implanted under the skin. This approach has been tried with a specially adapted CSII pump, which is entirely buried beneath the skin. The pump has a flexible reservoir that can be filled with insulin injected through the skin and the wall of the reservoir. Its batteries keep the small pump going and it can be programmed by external computer, another contribution from pacemaker technology. This device is still at the research stage.
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