The combination of extracorporeal carbon dioxide removal (ECCO2R) and hemofiltration is a possible therapeutic strategy for patients needing both lung and renal support. We tested the effects of the recirculation of ultrafiltrate on membrane lung (ML) CO2 removal (VCO2ML). Three conscious, spontaneously breathing sheep were connected to a commercially produced ECCO2R device (Hemolung; Alung Technologies, Pittsburgh, PA) with a blood flow of 250 ml/min and a gas flow of 10 L/min. A hemofilter (NxStage, NxStage Medical, Lawrence, MA) was interposed in series after the ML. Ultrafiltrate flow was generated and recirculated before the ML. We tested four ultrafiltrate flows (0, 50, 100, and 150 ml/min) for 25 min each, eight times per animal, resulting in 24 randomized test repetitions. We recorded VCO2ML, hemodynamics and ventilatory variables, and natural lung CO2 transfer (VCO2NL) and collected arterial and circuitry blood samples. VCO2ML was unchanged by application of ultrafiltrate recirculation (40.5 ± 4.0, 39.7 ± 4.2, 39.8 ± 4.2, and 39.2 ± 4.1 ml/min, respectively, at ultrafiltrate flow of 0, 50, 100, and 150 ml/min). Minute ventilation, respiratory rate, VCO2NL, and arterial blood analyses were not affected by ultrafiltrate recirculation. In the tested configuration, ultrafiltrate recirculation did not affect VCO2ML. This modular technology may provide a suitable platform for coupling CO2 removal with various forms of blood purification.
From the *Comprehensive Intensive Care Research Task Area, Battlefield Health and Trauma Research Institute, U.S. Army Institute of Surgical Research, Fort Sam Houston, San Antonio, Texas; †Department of Experimental Medicine, University Milano-Bicocca, Monza (MB), Italy; ‡Department of Anesthesiology and Intensive Care Medicine, University Hospital Bonn, Bonn, Germany; §Pediatric Department, University Hospital Bonn, Bonn, Germany; ¶Department of Perioperative Medicine and Intensive Care, San Gerardo Hospital, Monza (MB), Italy; and ‖Department of Trauma & Critical Care, San Antonio Military Medical Center, San Antonio, Texas.
Submitted for consideration December 4, 2013; accepted for publication in revised form February 22, 2014.
Disclaimer: The opinions or assertions contained herein are the private views of the author and are not to be construed as official or as reflecting the views of the Department of the Army or the Department of Defense.
Reprint Requests: Vittorio Scaravilli, MD, Comprehensive Intensive Care Research Task Area, Battlefield Health and Trauma Research Institute, U.S. Army Institute of Surgical Research, 3698 Chambers Pass, BHT 2, JBSA Fort Sam Houston, TX 78234-6315. Email: firstname.lastname@example.org.