Diagnostic procedures for catheter malfunction in programmable implantable intraperitoneal insulin infusion devices

To evaluate the roles of 1) abdominal radiography, 2) a pressure diagnostic procedure (PDP) using a standardized diluent infusion into the catheter sideport, and 3) radiocontrast imaging of the catheter lumen as procedures for diagnosing catheter malfunction in diabetic patients implanted with a programmable intraperitoneal infusion device.

Sixteen type I diabetic patients implanted with Infusaid programmable intraperitoneal insulin pumps were studied. The ability of the above three procedures to assist diagnosis of catheter malfunction and distinguish between occlusion and catheter breakage was retrospectively analyzed. Glycated hemoglobin was measured to determine the clinical importance of catheter malfunctions and decreases in pump flow due to insulin aggregation in the pump chamber.

Mean glycated hemoglobin levels increased significantly from 8.0 +/- 0.3 to 9.0 +/- 0.4% (P < 0.05) before and after catheter malfunction, but not during pump flow slowdowns. Mean peak pressure during PDP was 1.96 +/- 0.14 psi (P < 0.01 vs. normal) in reversibly occluded catheters and 1.86 +/- 0.35 psi (P < 0.05 vs. normal) in broken catheters, compared with 1.32 +/- 0.23 psi in normal catheters. Decay times during PDP were > 50 s for both reversibly occluded and broken catheters (P < 0.001 vs. normal of 3.6 +/- 0.82 s). Abdominal radiographs and sideport injections of contrast material were used to distinguish the types of broken catheters.

Catheter breakage and occlusion are complications in implantable insulin infusion systems and result in metabolic deterioration. The presence of a sideport allows pressure data and radiographic procedures to assist in determining the cause of catheter malfunction. A diagnostic algorithm was generated to improve efficiency in investigating catheter problems.