Design and Development of a Simple Screw Mechanism for a Low-Cost Neonatal Syringe Pump

Approximately 2.3 million neonates die annually. UNICEF proposes that the deployment of specialist, quality neonatal care could help reduce neonatal mortality rates by 28% by 2025. Syringe pumps are a key medical device for providing accurate and precise fluid and drug delivery to neonates. However, syringe pumps are expensive, complicated to use and not designed for the additional challenges of providing quality healthcare in low resource healthcare settings. Several open-source designs for low-cost syringe pumps already exist, however, they all have respective limitations.

To design and test a simple, open-source, screw mechanism, with the potential to be used in a future low-cost syringe pump.

A low-cost screw mechanism for a syringe pump, using a non-captive stepper motor, was developed. The prototype's accuracy was tested using 5mL, 20mL, 30mL and 60mL syringes at different rates. The rate was measured by recording the changing mass of saline fluid dispensed onto a weighing scale. The mean flow rate error from each run was calculated as the time taken to infuse 75% of the nominal volume, as per the ISO 286020:2020 standard.

The prototype produced a total mean flow rate error of 0.38%±1.62%. All errors were within the 3% limit (Z-score: 0.125) stipulated by the UNICEF and NEST360 target product profile. Compared to the other open-source designs, the prototype has the fewest parts, can accommodate a range of syringe sizes and is more accurate than many of the other open-source designs. Future work should involve testing the device with more viscous fluids, a greater range of rates and microstep settings, and improving the accuracy with further software and hardware development.