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AN EFFECTIVE PROGRAMMABLE INSULIN PUMP.

Many different types of implantable insulin pumps have been tried. The pumps, placed under the skin, deliver insulin to the peritoneal cavity from a reservoir that can be filled percutaneously every few weeks. Virtually all pumps have been open-loop systems that deliver insulin, but do not measure blood glucose and adjust insulin delivery accordingly (the ideal closed-loop system). Open-loop systems have typically delivered a pre-set amount of insulin: they cannot be programmed to adjust insulin delivery depending on blood glucose levels. Finally, past systems have had problems with aggregation of insulin within the pump and catheter, short battery life, erosion of skin above the implanted pump, and mechanical failure.

Investigators at John Hopkins University now report an open-loop pump that has been used in 18 patients for a mean of 18 months. The patient can program the pump to adjust the insulin dose depending on the blood glucose level (as determined by self-monitoring). The system achieved good control of blood sugar, without severe hyperglycemia or hypoglycemia. Few mechanical problems occurred, no skin erosions were seen, and few problems with insulin aggregation were noted (a new type of insulin-surfactant mix that reduces aggregation was used).

It remains to be seen whether insulin pumps can ever become sufficiently effective, reliable, and inexpensive to warrant widespread use, but this report indicates that progress is being made.

— ALK

Published in Journal Watch General Medicine September 8, 1989

Citation(s):

Saudek CD et al. A preliminary trial of the programmable implantable medication system for insulin delivery. N Engl J Med 1989 Aug 31 321 574-579.

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