Long-term implantation of a new implantable programmable insulin pump in two diabetic dogs

A positive-pressure implantable programmable pump with an integrated sideport and a detachable catheter was tested for long-term intraperitoneal insulin delivery in 2 diabetic dogs. Programming and refilling of the pump was simple and presented no problems during 28 months of pump function. During pump therapy an acceptable degree of glycemic control was maintained. No catheter occlusion occurred, and no skin erosions or infections were observed. Insulin in the pump reservoir was stable. After 9.5 months of pump function, flow progressively decreased because of insulin precipitation in the valved accumulator. Solubilization of these precipitates using 0.1 N NaOH injected in the reservoir and drained through the sideport normalized pump delivery rates. We conclude that this device is safe for long-term intraperitoneal insulin delivery. The sideport enables discrimination between different causes of pump malfunction and allows for the safe use of an alkaline solution to remove insulin precipitates, thus avoiding pump explantation.