Background
Thoracic artificial lungs (TALs) have been proposed as a bridge to transplant in patients with end-stage lung disease. Systemic embolic complications can occur following TAL attachment in the pulmonary artery to left atrium (PA-LA) configuration. Therefore, we evaluated the function of a compliant TAL (cTAL) attached via the proximal PA to distal main PA configuration.
Methods
The cTAL was attached to five (63 ± 0.9 kg) sheep in the PA-PA configuration. Device function and animal hemodynamics were assessed at baseline and with approximately 60%, 75%, and 90% of CO diverted to the cTAL. At each condition, dobutamine (0 and 5 mcg · kg−1 · min−1) was used to simulate rest and exercise conditions.
Results
At rest, CO decreased from 6.20 ± 0.53 L/min at baseline to 5.40 ± 0.43, 4.66 ± 0.31, and 4.05 ± 0.27 L/min with 50, 75, and 90% of CO to the cTAL (p<0.01 for each flow diversion vs. baseline). During exercise, CO decreased from 7.85 ± 0.70 L/min at baseline to 7.46 ± 0.55, 6.93 ± 0.51, and 5.96 ± 0.44 L/min (p=0.82, 0.19, and p<0.01 with respect to baseline) with 50, 75, and 90% of CO to the cTAL. The cTAL resistance averaged 0.46 ± 0.02 mmHg/(L/min) and did not vary significantly with cTAL blood flow rate.
Conclusions
Use of a cTAL may be feasible in the PA-PA setting if cTAL blood flow is held at < 75% of CO. To ensure a drop in CO < 10%, a cTAL flow rate < 60% of CO is advised.