Hemodynamic stability during arteriovenous carbon dioxide removal for adult respiratory distress syndrome: A prospective randomized outcomes study in adult sheep

To evaluate the ability of arteriovenous carbon dioxide removal (AVCO₂R) to maintain hemodynamic stability during treatment of adult respiratory distress syndrome (ARDS), we used our smoke/burn, LD₄₀ sheep model of ARDS. With onset of ARDS (PaO₂/FiO₂ < 200) animals were randomized to AVCO₂R (n = 20) or SHAM (n = 8). With AVCO₂R, the carotid artery (10-14 F) and jugular vein (14-16 F) were cannulated; SHAM received identical management, sparing the vessels. AVCO₂R maintained stable hemodynamics compared to SHAM at 48 hours; heart rate (114.8 ± 6.1 vs. 110.1 ± 11.0 beats/min.), mean arterial pressure (112 ± 5.1 vs. 107.0 ± 8.5 mm Hg), cardiac output (7.4 ± 0.5 vs. 7.5 ± 0.9 L/min.), pulmonary arterial pressure (26 ± 2.4 vs. 21 ± 1.3 mm Hg), pulmonary arterial wedge pressure (14.1 ± 1.8 vs. 14.0 ± 1.2 mm Hg), and central venous pressure (7 ± 1.6 vs. 8 ± 0.9 mm Hg). At 48 hours, AVCO₂R allowed significant reductions (p<0.05) in minute ventilation (13.6 ± 2.5 to 7.6 ± 0.8 L/min); tidal volume (TV) (389.4 ± 24.1 to 295.0 ± 10.1 mi); peak inspiratory pressure (PIP) (25.4 ± 9.2 to 18.8 ± 2.5 cm H₂O); RR (27.5 ± 0.7 to 21.6 ± 1.8 breaths/min); and FiO₂ (0.96 ± 0.00 to 0.48 ± 0.2) while normocapnia was maintained. AVCO₂R is an effective method of CO₂ removal during severe respiratory failure that is hemodynamically well tolerated.