Evaluation of splanchnic perfusion and oxygenation during positive end-expiratory pressure ventilation in relation to subcutaneous tissue gases and pH - An experimental study in pigs with oleic acid-induced lung injury

Evaluation of splanchnic perfusion and oxygenation was performed by measure ments of serosal tissue oxygen tension (PserO(2)) and intramucosal pH (pHi) in relation to subcutaneous oxygen tension (PscO(2)), subcutaneous carbon dioxide tension (PscCO(2)) and subcutaneous pH (pHsc) in pigs subjected to oleic acid-induced lung injury during ventilation with increasing levels of positive end-expiratory pressure (PEEP). Lung injury resulted in a general hypoxia and redistribution of perfusion away from the subcutaneous and spl anchnic tissues, illustrated by a decrease in PaO2 from 93 to 37 mm Hg (P < 0.01), PscO(2) from 45 to 17 mm Hg (p < 0.01), PserO(2) from 80 to 30 mm H g (p < 0.01) and pHi from 6.84 to 6.74 (p < 0.05) and a decrease of porta f low from 0.77 to 0.57 l/min. Application of PEEP up to 10-15 cm H2O resulte d in an increase of portal vein oxygen tension (PportaO(2)) from 21 to 34 m m Hg (P < 0.01), PscO(2) from 17 to 26 mm Hg (p < 0.06) and PserO(2) from 3 0 to 55 mm Hg (p < 0.05). At PEEP 20 cm H2O PserO(2) decreased to 47 mm Hg (p < 0.05). Porta flow decreased continuously with increasing levels of PEE P. PserO(2) correlated with PportaO(2) (r = 0.7, p < 0.001). pHi correlated poorly with PportaO(2) (r = 0.2) and porta flow (r = 0.4). PscO(2) and Pse rO(2) correlated well (r = 0.8, p < 0.001). In summary, splanchnic perfusio n and oxygenation was better reflected by serosal oxygen tension than pHi i n the colon. Changes in serosal oxygenation of the colon paralleled changes in subcutaneous tissue oxygenation. Copyright (C) 2001 S. Karger AG, Basel .