Pediatric Artificial Lung: A Low-Resistance Pumpless Artificial Lung Alleviates an Acute Lamb Model of Increased Right Ventricle Afterload

Abstract

Lung disease in children often results in pulmonary hypertension and right heart failure. The availability of a pediatric artificial lung (PAL) would open new approaches to the management of these conditions by bridging to recovery in acute disease or transplantation in chronic disease. This study investigates the efficacy of a novel PAL in alleviating an animal model of pulmonary hypertension and increased right ventricle afterload. Five juvenile lambs (20-30 kg) underwent PAL implantation in a pulmonary artery to left atrium configuration. Induction of disease involved temporary, reversible occlusion of the right main pulmonary artery. Hemodynamics, pulmonary vascular input impedance, and right ventricle efficiency were measured under 1) baseline, 2) disease, and 3) disease + PAL conditions. The disease model altered hemodynamics variables in a manner consistent with pulmonary hypertension. Subsequent PAL attachment improved pulmonary artery pressure (p = 0.018), cardiac output (p = 0.050), pulmonary vascular input impedance (Z.0 p = 0.028; Z.1 p = 0.058), and right ventricle efficiency (p = 0.001). The PAL averaged resistance of 2.3 ± 0.8 mm Hg/L/min and blood flow of 1.3 ± 0.6 L/min. This novel low-resistance PAL can alleviate pulmonary hypertension in an acute animal model and demonstrates potential for use as a bridge to lung recovery or transplantation in pediatric patients with significant pulmonary hypertension refractory to medical therapies.

Figure 1. Device design and computational fluid dynamics modeling

A) Schematic of the Device Design; A representative planar view of the computationally obtained velocity (B) and pressure (C).

Figure 2

Experimental setup

Figure 3. In vitro gas exchange and pressure drop

A) Average oxygen (O₂) transfer; B) Average carbon dioxide (CO₂) removal; C) Average resistance across the device

Figure 4. Pulmonary vascular input impedance spectrum

Z.0, zeroth harmonic impedance; Z.1, first harmonic impedance; Z.2, second harmonic impedance; Z.3, third harmonic impedance; Z.C, characteristic impedance. * denotes a significant difference between Baseline and Disease Model. # denotes a significant difference between Disease Model and Disease