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In Vitro Characterization of the Pittsburgh Pediatric Ambulatory Lung
Ryan A Orizondo1, Alexandra G May1,2, Shalv P Madhani1,3
1From the McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania.
Insights
The Pittsburgh Pediatric Ambulatory Lung (P-PAL) is a wearable device offering respiratory support for children. This innovative blood pump and oxygenator allows ambulation, potentially improving outcomes for pediatric respiratory failure.
Area of Science:
- Biomedical Engineering
- Pediatric Critical Care
Background:
- Pediatric respiratory failure significantly impacts child morbidity and mortality.
- Current respiratory support systems often immobilize patients, potentially worsening long-term outcomes.
- There is a need for ambulatory respiratory support solutions for children.
Purpose of the Study:
- To design and evaluate the Pittsburgh Pediatric Ambulatory Lung (P-PAL), a wearable blood pump and oxygenator for pediatric respiratory support.
- To assess the P-PAL's ability to provide ambulation and significant respiratory assistance.
- To ensure the device meets performance specifications for flow, oxygenation, and hemocompatibility.
Main Methods:
- Computational fluid dynamics and numerical modeling were used for device design and performance prediction.
- A prototype P-PAL was tested in vitro using blood analog fluid and human blood.
- Pressure-flow curves, oxygen exchange rates, and normalized index of hemolysis (NIH) were measured.
Main Results:
- The P-PAL achieved target blood flows (1-2.5 L/min) against relevant pressures.
- Oxygen exchange rates reached 108 ml/min, meeting the design target for respiratory support.
- Low device-induced hemolysis was observed (NIH 0.022-0.027 g/100 L) within the intended flow range.
Conclusions:
- The P-PAL design successfully met pumping, oxygenation, and hemolysis specifications.
- This wearable device demonstrates potential to improve treatment for pediatric respiratory failure by enabling ambulation.
- The P-PAL offers a promising alternative to current bedridden respiratory support methods for children.
Abstract:
Acute and chronic respiratory failure are a significant source of pediatric morbidity and mortality. Current respiratory support options used to bridge children to lung recovery or transplantation typically render them bedridden and can worsen long-term patient outcomes. The Pittsburgh Pediatric Ambulatory Lung (P-PAL) is a wearable pediatric blood pump and oxygenator (0.3 m surface area) integrated into a single compact unit that enables patient ambulation. The P-PAL is intended for long-term use and designed to provide up to 90% of respiratory support in children weighing 5-25 kg. Computational fluid dynamics and numerical gas exchange modeling were used to design the P-PAL and predict its performance. A P-PAL prototype was then used to obtain pressure versus flow curves at various impeller rotation rates using a blood analog fluid. In vitro oxygen exchange rates were obtained in blood in accordance with ISO standard 7199. The normalized index of hemolysis (NIH) was measured over a 6 hour period at blood flow rates of 1 and 2.5 L/min. The P-PAL provided blood flows of 1-2.5 L/min against the pressure drop associated with its intended-use pediatric cannulas. The oxygen exchange rate reached a maximum of 108 ml/min at a blood flow rate of 2.5 L/min and met our respiratory support design target. Device-induced hemolysis was low with NIH values of 0.022-0.027 g/100 L in the intended blood flow rate range. In conclusion, the current P-PAL design met our pumping, oxygenation, and hemolysis specifications and has the potential to improve treatment for pediatric respiratory failure.
