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Design and validation of a diaphragm pump for pediatric CRRT during ECMO
Arvind Santhanakrishnan1, Trent Nestle, Brian L Moore
1Wallace H. Coulter School of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA - USA.
Insights
A new diaphragm pump accurately measures fluid balance for pediatric patients on extracorporeal membrane oxygenation (ECMO) requiring continuous renal replacement therapy (CRRT). This novel design improves accuracy over existing devices for critical care.
Area of Science:
- Biomedical Engineering
- Pediatric Nephrology
- Critical Care Medicine
Background:
- Children on extracorporeal membrane oxygenation (ECMO) face high risks of acute kidney injury (AKI).
- Continuous renal replacement therapy (CRRT) is standard for pediatric AKI, but current devices struggle with accuracy at low flow rates.
- Inaccurate fluid balance (FB) during CRRT in pediatric ECMO patients is a significant clinical challenge.
Purpose of the Study:
- To design and validate a novel pump system for accurate CRRT fluid balance in pediatric ECMO patients.
- To address the limitations of existing CRRT pumps in pediatric critical care settings.
- To improve patient outcomes by ensuring precise fluid management during ECMO support.
Main Methods:
- A 7 mL stroke volume diaphragm pump was prototyped using a flexible membrane and hydraulic fluid.
- In vitro testing compared the diaphragm pump against standard intravenous (IV) pumps across relevant pressure ranges.
- The diaphragm pump was integrated into a CRRT circuit alongside ECMO to evaluate fluid balance accuracy.
Main Results:
- The novel diaphragm pump demonstrated significantly improved fluid transport efficiency with errors as low as 1-5 ml/hr.
- Unlike IV pumps, the diaphragm pump exhibited minimal variation in stroke volume with changing source pressures.
- Integration of the diaphragm pump into a CRRT-ECMO circuit substantially enhanced fluid balance accuracy.
Conclusions:
- A novel diaphragm pump concept offers a promising solution for accurate CRRT in pediatric ECMO patients.
- In vitro validation confirmed the superior accuracy of the new pump compared to conventional CRRT pumps.
- This innovation has the potential to improve fluid management and patient care in pediatric critical care.
Purpose:
Children requiring artificial heart-lung support through extracorporeal membrane oxygenation (ECMO) are at increased risk of developing acute kidney injury (AKI). Continuous renal replacement therapy (CRRT) is the preferred method of treatment in pediatric AKI patients. CRRT devices are noted to provide inaccurate fluid balance (FB) when operated under low flow rates seen in children. We present the design and validation of a novel pump concept to provide accurate pediatric CRRT during ECMO.
Methods:
A diaphragm pump was prototyped with a working stroke volume (SV) of 7 mL. Fluid transport occurs by periodic expansion and contraction of a flexible membrane due to pressure fluctuations of hydraulic fluid contained below its surface. Comparison of intravenous (IV) pumps to the diaphragm pump was conducted in vitro across the range of pressures observed during CRRT in ECMO. The pump was integrated into a CRRT circuit parallel with ECMO and FB accuracy was evaluated.
Results:
The pump design improved efficiency of fluid transport, with flow rate errors as low as 1-5 ml/hr as compared to IV pumps (15-50 ml/hr). The SV of IV pumps increased with source pressure in a nearly linear manner compared to the minimal variation produced by the diaphragm pump. Inclusion of the diaphragm pump in a conventional CRRT circuit with ECMO improved the FB accuracy.
Conclusions:
A novel diaphragm pump concept has been presented for providing CRRT during ECMO in the pediatric population. Improvement of the pump accuracy compared to currently used CRRT pumps was demonstrated via in vitro testing.
