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Syringe pump

For every ventilator used there needs to be about 3-4 electronic syringe pump to keep patients sedated, keep up blood pressure, and several other drugs that are necessary during anaesthesia. The pharmaceuticals are given constantly during long time (1-2 weeks) and precision and dose titration is important. There will be a big shortage of such syringe pump systems during the covid-19 peak.

Important update: At Skåne University Hospital the need seems as of 2020-04-09 to be possible to fill by standard supply chains. The project is therefore temporarily halted. If you work at a hospital and see no other options for supply chains to provide syringe pumps please let us know and then the project will be revived

There are quite mature open source design available for syringe pumps. One such is the Y-struder project. The aim of this project is to 1) Help Swedish healthcare to deal with peak Covid-19 by manufacture syringe pumps, 2) provide a well documented open source project for design of syringe pumps for emergency medical usage.

Based on the above we are now gearing this project up and are seeking for more volunteers with a wide range of competencies, contact Einar Heiberg and David Nordlund. The aim is to have an early prototype to show in two weeks (2020-04-21).

Next step is kick-off meeting on 2020-04-08.

Preliminary requirements

  • Infusion pump for delivering pharmaceutical used in emergency medicine situations when ordinary medical technology equipment is not available.
  • Compatible with 50ml and 20ml syringes of the following types: BD Plastik, BBraun (syringes seems very standardized).
  • Alarm possible when setting are not delivered.
  • Alarm when there are 5, 3, 1 minute left until syringe is empty.
  • Alarm for obstruction/occlusion.
  • Alarm systems according to international standards.
  • System should understand if syringe is not completely filled from start, i.e. when loaded with a syringe the pump needs to detect where the piston end is.
  • Set injection speed in ml/min.
  • Display indicating injection speed, injected volume / volume left [ml].
  • System that can measure how far the piston actually have come to be able to sound alarm if delivered medicine is not same as plan.
  • Free flow prevention (the pump must hold the piston to prevent it from sliding by itself due to negative pressure in the flow line).
  • Easy load of syringe.
  • Intuitive interaction design.
  • Accuracy of 5% or better. Defined as; if it is expected to take x min to empty the syringe based on volume in syringe and pump setting the time it took to empty the syringe should be within 5% of x min.

Here is an article how_safety_features_make_or_break_infusion_pump_design.pdf on principles for syringe pump design (paper is on both syringe pump and volume pump).

Nice to have

  • Some system so that the equipment knows the size of the syringe
  • Set the content (pharmaceutical) so that this is displayed
  • Stackable and attachable to standard poles.
  • Ability to set patient weight and drug concentration to allow displaying mg/kg/min (or microg/kg/min)
  • Bolus function: the ability to momentarily inject a set dose at a button press
  • It should be reasonably easy to disinfect the surfaces that operators touch, such as the keypad

Preliminary design

  • Arduino*2 or Arduino+Raspberry Pie system for control.
  • 3D printed design for fast prototyping / manufacture.
  • Standard stepmotor.
  • System to detect rotation of stepmotor.
  • Load sensor to detect obstruction.
  • Low level control from the open source Y-struder project.
  • Possible flow chart for the menus found here syringe_pump_flow_chart_2020-04-08b.xlsx

Uncertain design parameters

  • Need for battery backup?
  • Power supply (12V?)

User interface

One way to achieve a user interface that can be wiped off with disinfectant is to use a membrane keyboard for user input. They seem to typically be available in matrix shapes of sizes 1×4, 3×4 and 4×4.

Electrokit has a few self-adhesive models with pre-marked symbols:

Elfa Distrelec has keyboards in the same shape, also self-adhesive, with customizable key symbols:*&filter_Buyable=1&filter_Category3=Tangentbord&filter_Manufacturer=Apem

Test protocol

On this page there is a stub for a test protocol


MilestoneTarget deadline
Assignment of teams2020-04-09
First prototype; no casing, set flow in ml/min, occlusion detection2020-04-21
Second prototype; casing and “keypad”-
Usability testing-
Third prototype; set ml/min/kg, display of pharmaceutical-
Final testing-
Start of production-

Current team, more volunteers wanted!

NameOrgRole / competence
Einar Heiberg 3DPrint SUS Project leader
David Nordlund Klinfys Lund University / SUS Deputy project leader, clinical input
Erik Ekbom 3DPrint SUS 3D printing
Philip Bernborg 3DPrint SUS 3D printing
Muris Imsirovic 3DPrint SUS CAD, 3D printing
Per Nordqvist Medicinsk Teknik SUS Risk analysis
Erik Cederberg3D verkstanCAD
Anton Eliasson AxisSoftware
Azal AlothmaniAxisElectronics, programming, design
Leif Barendt Lomma Elektronik design Electronic CAD and development

We need to organise into sub team, suggested teams are

  • Electronics and low level control (lead TBD)
  • High level software design, including user interface (lead TBD)
  • Riskanalysis, verification, validation and testing (lead Einar)
  • Documentation (lead TBD)
  • Communiction (lead TBD)

Timeline (latest first)

  • 2020-04-09 Project temporarily on hold.
  • 2020-04-08 Call for more volunteers, added first testing protocol, updated team list. Preliminary flow chart for menus by David
  • 2020-04-07 Edits in requirements by Einar. Decision to scale up project based on feedback from health care.
  • 2020-04-06 First design meeting. Start of medical need inventory.
  • 2020-04-05 Minor adds/edits in requirements by Einar.
  • 2020-04-05 Minor adds/edits in requirements & nice to have by David.
  • 2020-04-04 Software developer on board.
  • 2020-04-03 Formal project start.
syringepump.txt · Last modified: 2020/04/09 19:14 by