683: Tissue Inflammation in Awake Sheep Subjected to Extracorporeal Acid Load Co2 Removal (ALCO2R)
ARMY INST OF SURGICAL RESEARCH FORT SAM HOUSTON TX
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Learning Objectives ARDS remains a significant medical problem in ICU patients and requires mechanical ventilation which by itself may be injurious. ALCO2R is a unique strategy to reduce ventilator settings to minimize additional lung damage in patients with ARDS. We tested the hypothesis that ALCO2R does not induce an inflammatory response in target organs. MethodsConscious spontaneously breathing sheep n6 were connected to a Hemolung Alung Technologies, Pittsburgh, PA membrane lung ML via heparin-coated tubing and a dual lumen catheter inserted in the right jugular vein. A hemofilter Purema, Nx Stage Medical, Lawrence, MA was set up in series after the ML with a pump for recirculation of ultrafiltrate and reinfusion before the ML. 1.5 mEqmin of lactic acid was infused into the ultrafiltrate to acidfy blood locally and enhance CO2 removal by the ML. Animals were subjected to ALCO2R or standard CO2 removal without acidification for 12 hr periods twice over a 48 hr period and each sheep served as its own control. Sheep were then euthanized and liver and lungs were flash frozen and analyzed for select indices of oxidative stress and cytokines. Results The efficiency of CO2 removal was 70 higher during ALCO2R than without acid. Cardiac output and oxygen consumption were about 6 8 higher during ALCO2R than without acid. pHa was normal and lactate higher in ALCO2R and markers of kidney and liver function were within the normal range. Lung and liver indices of lipid peroxidation, antioxidant status, as well as glutathione levels and indices of nitrosative stress were similar to historic controls. Lung and liver IL-1 and IL-8 as markers of inflammation were not significantly elevated over the normal range in either tissue. Conclusions Spontaneously breathing sheep subjected to ALCO2R were able to maintain ventilator status with improved efficiency in CO2 removal.
- Anatomy and Physiology
- Medicine and Medical Research