User's Manual

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CHAPTER 10 Troubleshooting Pump
System under-delivery
Potential under-delivery of insulin by the Medtronic MiniMed 2007D Implant-
able Insulin Pump System may result in an increase in daily programmed insulin
usage, difficulty maintaining euglycemia, occasional hyperglycemia, and prob-
lems calculating refill accuracy. This chapter describes how to diagnose potential
Pump System problems that may cause insulin under-delivery, and offers poten-
tial Pump and Catheter solutions to correct for under-delivery.
Diagnostic procedures
When refill procedures reveal the possibility of a Pump System under-delivery
problem, diagnostic procedures must be performed to verify if there is a problem
with either the Pump or Catheter. The Stroke Volume Measurement Procedure
tests Pump function, while the Pressure Measurement Procedure tests Catheter
patency. These diagnostic procedures should be performed according to the steps
outlined in Appendix G.
Under-delivery caused by backflow
Backflow results in the inverted flow of insulin through the Pump System. Back-
flow is caused by insulin deposits that compromise valve integrity, and allow the
negative reservoir pressure (vacuum) to pull insulin back into the reservoir. To
compensate for this under-delivery, the user can program appropriate increases in
their basal rates and bolus amounts.
Backflow conditions are characterized by increases in daily programmed insulin
usage, difficulty in maintaining euglycemia, increasingly negative refill accuracy
and sometimes hyperglycemia. Confirm a backflow condition by performing the
Stroke Volume Measurement Procedure. Then rinse the Pump System with
NaOH solution to dissolve insulin deposits, following the Pump Rinse Procedure
outlined in Appendix E.