Mucosal tissue oxygenation of the porcine jejunum during normothermic cardiopulmonary bypass

Abstract

Cardiopulmonary bypass (CPB) has been associated with intestinal tissue hypoxia, but direct measurements of mucosal oxygenation have not been performed. In anaesthetized pigs, jejunal mucosal oxygen tension and microvascular haemoglobin oxygen saturation were measured by a Clark-type electrode and tissue reflectance spectrophotometry. In pigs, normothermic CPB with systemic oxygen transport equivalent to baseline values was performed. In control animals, mucosal oxygen tension and mucosal haemoglobin oxygen saturation were mean 5.01 (SD 1.08) kPa and 38.0 (2.3)%, respectively. CPB was associated with a decrease in mucosal oxygen tension to 2.26 (1.21) kPa, decrease in mucosal microvascular haemoglobin oxygen saturation to 26.0 (3.9)% and appearance of oscillations in mucosal microvascular haemoglobin oxygen saturation. With CPB, arterial lactate concentrations increased from 1.77 (1.37) to 3.52 (1.58) mmol litre-1, but transvisceral lactate and splanchnic venous-arterial carbon dioxide tension gradients remained unchanged. Our results support the concept that CPB is associated with diminished oxygenation of intestinal mucosa that is probably caused by regional redistribution.

Extracorporeal Circulation Induced Microvascular Perfusion Injury of the Small Bowel

“…This is extremely important, because only slight changes in perfusion pressure and/or CO result in an immediate and significant change in microvascular blood flow of the small bowel. The phenomenon of impaired gastrointestinal perfusion due to CPB was observed by several authors [13][14][15][16]. In our experiments, we could demonstrate clearly that a pLHB induces a microvascular perfusion injury of the small bowel despite unchanged macrohemodynamics.…”

Jejunal tissue oxygenation and microvascular flow motion during hemorrhage and resuscitation

“…These oscillations increased in amplitude and frequency during hemorrhage, whereas gastric motility remained constant. During normothermic cardiopul-monary bypass (CPB), we reported the onset of HBjO 2 oscillations with frequencies of 5-7 cycles/min simultaneously with a significant drop in PO 2muc after institution of CPB (12). There were no significant differences in mean arterial pressure and systemic O 2 delivery between sham and CPB animals.…”

Ischemic Intestinal Injury during Cardiopulmonary Bypass Does Not Show an Association with Neutrophil Activation

“…A notable reduction in capillary density was observed, but the underlying mechanism remained open [6] . CPB has been associated with diminished oxygenation of intestinal mucosa that is probably caused by oxygen delivery/demand mismatch and regional redistribution [27,28] . Leukocyte/endothelial cell interaction within microcirculation and a formation of ROS during extracorporeal circulation have been demonstrated by Kamler et al [29] .…”