Mucosal tissue oxygenation of the porcine jejunum during normothermic cardiopulmonary bypass

Cardiopulmonary bypass (CPB) has been associated with intestinal tissue hyp oxia, but direct measurements of mucosal oxygenation have not been performe d. In anaesthetized pigs, jejunal mucosal oxygen tension and microvascular haemoglobin oxygen saturation were measured by a Clark-type electrode and t issue reflectance spectrophotometry. In pigs, normothermic CPB with systemi c oxygen transport equivalent to baseline values was performed. In control animals, mucosal oxygen tension and mucosal haemoglobin oxygen saturation w ere mean 5.01 (so 1.08) kPa and 38.0 (2.3)%, respectively. CPB was associat ed with a decrease in mucosal oxygen tension to 2.26 (1.21) kPa, decrease i n mucosal microvascular haemoglobin oxygen saturation to 26.0 (3.9)% and ap pearance of oscillations in mucosal microvascular haemoglobin oxygen satura tion. With CPB, arterial lactate concentrations increased from 1.77 (1.37) to 3.52 (1.58) mmol litre(-1), but transvisceral lactate and splanchnic ven ous-arterial carbon dioxide tension gradients remained unchanged. Our resul ts support the concept that CPB is associated with diminished oxygenation o f intestinal mucosa that is probably caused by regional redistribution.