Technology, School of Biomedical. Engineering, Atlanta, GA. (2) Children's Healthcare of. Atlanta at Egleston, Atlanta, GA. (3) Emory University, School of.
Development of a Novel Fluid Management System for Accurate Continuous Hemofiltration in Extracorporeal Membrane Oxygenation (ECMO) Lakshmi P. Dasi(1), Philippe Sucosky(1), Stephen Goldman(1), Matthew Paden(2,3), James Fortenberry(2), Ajit P. Yoganathan(1) (1) Georgia Institute of Technology, School of Biomedical Engineering, Atlanta, GA
(2) Children’s Healthcare of Atlanta at Egleston, Atlanta, GA
(3) Emory University, School of Medicine, Atlanta, GA
Outline • • • • • •
Background Motivations Objectives Design description Future work Conclusions
Background
Motivations
Objectives
Design description
Future work
Conclusions
Outline • • • • • •
Background Motivations Objectives Design description Future work Conclusions
Background
Motivations
Objectives
Design description
Future work
Conclusions
Outline • • • • • •
Background Motivations Objectives Design description Future work Conclusions
Background
Motivations
Objectives
Design description
Future work
Conclusions
Outline • • • • • •
Background Motivations Objectives Design description Future work Conclusions
Background
Motivations
Objectives
Design description
Future work
Conclusions
Outline • • • • • •
Background Motivations Objectives Design description Future work Conclusions
Background
Motivations
Objectives
Design description
Future work
Conclusions
Outline • • • • • •
Background Motivations Objectives Design description Future work Conclusions
Background
Motivations
Objectives
Design description
Future work
Conclusions
Extracorporeal Membrane Oxygenation (ECMO) • “Artificial heart-lung machine” • Support infants, children, and adults with : flow probe
arterial return cannula
– lung failure – heart failure – severe infections
venous drain cannula
membrane oxygenator
ECMO bladder roller pump
membrane oxygenator roller pump
ECMO components Background
Motivations
Objectives
Typical ECMO setup Design description
Future work
Conclusions
Continuous Venovenous Hemofiltration (CVVH) • Used for kidney failure as well as fluid management • Ultrafiltrate removed from blood and replaced by electrolyte solution • Allows correction of electrolytes as well as ability to remove volume • Well tolerated by sick patients
P replacement fluid hemofilter IV pump
IV pump
(Foland et al., 2004) ultrafiltrate
CVVH components Background
Motivations
Objectives
Design description
Future work
Conclusions
ECMO + CVVH: Advantages • Compensates for fluid accumulation during ECMO treatment
flow probe
(Sell, 1987; Meyer, 2001) ultrafiltrate
IV pump
IV pump
replacement fluid
hemofilter membrane oxygenator roller pump
ECMO bladder
• Eliminates need for diuretics • Enhances nutrition • Decreases exposure to medications with significant side effects (Hoover et al., 2006)
ECMO + CVVH circuit Background
Motivations
Objectives
Design description
Future work
Conclusions
ECMO+CVVH: Issues • Typical ECMO pressure >> physiologic pressure • Concerns about IV pump accuracy
Background
Motivations
Objectives
Design description
Future work
Conclusions
ECMO + CVVH: Issues • High pressure and flow lead to: – Increased ultrafiltrate removal from patient – Decreased replacement of fluid to patient
• The smaller the patient, the worse the problem
Rapid dehydration, leading to shock
Background
Motivations
Objectives
Design description
Future work
Conclusions
ECMO + CVVH: Issues
Implementation of CVVH with ECMO
Background
Motivations
Objectives
Design description
Future work
Conclusions
Objectives •
To design a CVVH system that satisfies the following requirements: – Easy integration with ECMO system – Production of exact or negative fluid balance between toxin clearance and electrolyte replacement – Fluid replacement flow rate of up to 8 L/hour – Preservation of patient’s safety – Maintenance of sterility – Easy operation – Compact size
Background
Motivations
Objectives
Design description
Future work
Conclusions
Design Principles replacement fluid
linear piston
open valve
negative balance bag
linear piston
drain
syringe pump to remove replacement fluid to ECMO bladder
hemofilter
Phase 1: electrolyte replacement and toxin clearance Background
replacement fluid
negative balance bag
Motivations
Objectives
closed valve
drain
syringe pump to remove replacement fluid to ECMO bladder
hemofilter
Phase 2: Replacement fluid chamber refill and toxin chamber drainage Design description
Future work
Conclusions
Design Implementation translating arm syringe
cradle
linear positioner
Accurate fluid balance system
Pinch valve (Bio-Chem Valve Inc.)
Linear positioner (Parker Hannifin) Background
Motivations
Objectives
Design description
Future work
Conclusions
CVVH Design Solution replacement fluid drawer
- balance drawer toxin clearance drawer
hemofilter
pump compartment
pump drive
mounting stand
Front panel Background
Rear panel Motivations
Objectives
Design description
Future work
Conclusions
CVVH Design Solution: Front Panel from membrane oxygenator
hemofilter
replacement fluid bag
pinch valve 1
- balance bag
pinch valve 3 “zero-balance” pump compartment
to ECMO bladder pinch valve 2
replacement fluid pump
toxin clearance pump negative balance pump stepper drive
“negative balance” pump compartment Background
Motivations
Objectives
Design description
Future work
Conclusions
from membrane oxygenator
Fluid Balance – Phase 1 Replacement fluid delivery and ultrafiltrate clearance Device function filtered blood
1
2
to ECMO bladder
fluid replacement bag
ultrafiltrate toxin bag
1
fluid replacement syringe
2
toxin clearance syringe
Pinch valves status Background
Motivations
Objectives
Design description
Future work
Conclusions
from membrane oxygenator
Fluid Balance – Phase 2 Replacement fluid syringe refill and toxin syringe drainage Device function filtered blood
1
2
to ECMO bladder
fluid replacement bag
ultrafiltrate toxin bag
1
fluid replacement syringe
2
toxin clearance syringe
Pinch valves status Background
Motivations
Objectives
Design description
Future work
Conclusions
Negative Fluid Balance – Phase 1
from membrane oxygenator
Replacement fluid removal Device function filtered blood 1 3
to ECMO bladder
fluid replacement bag
replacement fluid - balance bag
1
fluid replacement syringe
3
- balance syringe
Pinch valves status Background
Motivations
Objectives
Design description
Future work
Conclusions
Negative Fluid Balance – Phase 2
from membrane oxygenator
- balance syringe drainage Device function
1 replacement fluid
3
to ECMO - balance bag bladder
- balance syringe
3
Pinch valves status Background
Motivations
Objectives
Design description
Future work
Conclusions
In-Room Implementation
Background
Motivations
Objectives
Design description
Future work
Conclusions
Future Work • Valve synchronization and stepper drive programming • Mechanical validation • In vivo animal testing • Clinical testing and implementation Background
Motivations
Objectives
Design description
Future work
Conclusions
Conclusions • A novel CVVH circuit has been designed to complement an ECMO loop • Accurate pump system achieving exact/negative fluid balance • Theoretical max flow rate: 8 L/hour • Compact system fits easily near the patient’s bed • Simple operation via stepper drive interface Background
Motivations
Objectives
Design description
Future work
Conclusions
Acknowledgments • Funding Agency: – Health Systems Institute (HSI) at Georgia Tech (Funding)
• Scott Wagoner (ECMO Specialist, CHOA) • Members of the Cardiovascular Fluid Mechanics Laboratory (Georgia Tech) • Colly Mitchell (Administrative Assistant, Georgia Tech)
