Evaluation of a low-cost, low-power syringe pump to deliver magnesium sulfate intravenously to pre-eclamptic women in a Malawian referral hospital

Abstract

Background: Magnesium sulfate is an affordable and effective treatment for pre-eclampsia and eclampsia. In settings where infusion pumps are not available to regulate the flow rate of intravenous delivery, healthcare providers must administer magnesium sulfate (MgSO4) via time-consuming and painful, large-volume intramuscular injections. As an alternative to costly commercially available syringe pumps, we developed AutoSyp, an accurate, low-cost, and low-powered syringe pump designed to meet the needs and constraints these low-resource settings. This paper describes results of a pilot study to evaluate the feasibility of using AutoSyp to administer MgSO4 intravenously to women suffering from pre-eclampsia at a referral hospital in Blantyre, Malawi.

Methods: AutoSyp was programmed to deliver MgSO4 following the Zuspan regimen to pregnant and post-partum women suffering from pre-eclampsia at Queen Elizabeth Central Hospital in Blatnyre, Malawi. Given the selection of either loading or maintenance dose on AutoSyp's user interface, the flow rate was automatically programmed to dispense 60 mL/h or 5 mL/h of 20% MgSO4 solution, respectively. During each treatment, the dispensed volume was automatically calculated by the device based on the plunger position and stored on a computer for accuracy analysis of the mean flow rate and total volume delivered. The clinical results for both the loading and maintenance dose administrations were compared to the device's accuracy during tests performed in the laboratory setting.

Results: Twenty-two women were enrolled in this study. In both the clinical and laboratory settings, the mean flow rate errors for the loading and maintenance dose infusions were under 2%. During 466 h of testing, the device sounded 129 occlusion alarms across 14 subjects. Of these, 71 alarms were false positives.

Conclusion: Results of this study support the use of AutoSyp as a less painful and accurate means of MgSO4 administration in clinical environments that lack infusion systems. There were a large number of false alarms in the current system which will be addressed in future designs. AutoSyp maintains the comfort of intravenous MgSO4 administration, but unlike commercially available syringe pumps, it is capable of operating with a variety of syringe brands and sizes and requires no additional consumables. AutoSyp's appropriate design will benefit its implementation and sustained use in low-resource settings.

Trial registration: Trial registered prospectively on November 18, 2014 with ClinicalTrials.gov ( NCT02296931 ).

Keywords: Global Health; Infusion pump; Low-resource settings; Magnesium sulfate; Malawi; Maternal Health; Pre-eclampsia; Syringe pump.

Figures

Fig. 1

The AutoSyp Device. a AutoSyp can be used with all major brands of syringes and giving sets. The simple user interface includes an LCD screen and keypad. b The redesign includes a simplified drive mechanism used to rewind the spring. A robust load cell is used in place of the pressure pad for occlusion detection