Therapeutic options for battlefield treatment of lung injury are limited. We evaluated an extracorporeal veno-venous CO2 removal device (Hemolung, ALung Technologies Inc., Pittsburgh, PA), for its ability to reduce minute ventilation (MV) in anesthetized swine.
Seven anesthetized (ketamine/midazolam) swine (54.2+0.8 kg standard error of the mean (SEM)) were placed on volume-controlled ventilation with MV titrated to normocapnea (PaCO2 35–45 mmHg). After a 20 α/kg bolus of heparin, a 15-Fr. dual-lumen catheter was inserted in the right jugular vein. The proximal set of catheter openings resided in the superior vena cava and was used to withdraw venous blood. The blood passed through a saline-primed 300-ml-volume gas-exchange device. After CO2 removal, blood was re-infused through the distal tip of the catheter residing in the right atrium. MV was titrated to maintain normocapnea. Animals were maintained for 72 hours with round-the-clock ICU care. MV, heart rate (HR), systolic arterial pressure (SAP), PaO2, PaCO2, CO2 removal rate (CO2 rem) and Hemolung blood flow (BF), activated clotting time (ACT) were measured.
See table. Average CO2 removal was 72±1.2 ml/min at mean blood flows of 447±5 ml/min and remained steady over 72 hours. PO2 and vital signs were well maintained. Heparin requirements were low.
Use of the Hemolung allowed for up to a 50% reduction in MV throughout the 72-hour study. “Respiratory dialysis” via the Hemolung system may be an effective adjunct and a viable future alternative to mechanical ventilation.
Refinement of this technology may transfer adult extracorporeal lung support from specialized units to aeromedical evacuation platforms and community hospital ICUs. Further, new strategies that reduce ventilator-induced lung injury in ARDS will be explored.
Andriy Batchinsky, No Financial Disclosure Information; Product/procedure/technique that is considered research and is NOT yet approved for any purpose. The Hemolung system is currently undergoing an FDA approval process for extracorporeal CO2 removal in patients with chronic obstructive pulmonary disease. At this time this device is not yet approaved for the use and thus the materials presented in this abstract are research materials.