Bubble formation occurs in insulin pumps in response to changes in ambient temperature and atmospheric pressure but not as a result of vibration

Abstract

Introduction: Bubble formation in insulin pump giving sets is a common problem. We studied change in temperature, change in atmospheric pressure, and vibration as potential mechanisms of bubble formation.

Methods: 5 Animas 2020 pumps with 2 mL cartridges and Inset II infusion systems, 5 Medtronic Paradigm pumps with 1.8 mL cartridge and Quickset and 3 Roche Accu-chek pumps with 3.15 mL cartridges were used. Temperature study: insulin pumps were exposed to a temperature change from 4°C to 37°C. Pressure study: insulin pumps were taken to an altitude of 300 m. Vibration study: insulin pumps were vigorously shaken. All were observed for bubble formation.

Results: Bubble formation was observed with changes in temperature and atmospheric pressure. Bubble formation did not occur with vibration.

Discussion: Changes in insulin temperature and atmospheric pressure are common and may result in bubble formation. Vibration may distribute bubbles but does not cause bubble formation.

Keywords: Insulin Pump Therapy; Parenting Stress; Pediatric Diabetes.

Figure 1

Mathematical modeling of bubble formation in insulin pump cartridges (3 mL solid line, 2 mL dotted line, and 1.8 mL dashed line) and lines during an increase in temperature from 4°C to 37°C. Henry's law (1) was used to graph the predicted bubble formation in insulin as the temperature changes between 4°C and 37°C.

Figure 2

Bubbles present in an insulin pump cartridge and line following an increase in temperature from 4°C to 37°C. The insulin cartridge and line containing aspart insulin was cooled to 4°C in a fridge and then moved to an oven at 37°C.