Extracorporeal Circulation and Intestinal Microcirculation: Pathophysiology and Therapeutical Options

The impact of selective visceral perfusion on intestinal macrohemodynamics and microhemodynamics in a porcine model of thoracic aortic cross-clamping

“…Relevant factors contributing to damage of the mucosa can also be a reduced functional capillary density of the small bowel and shunting of the microcirculation, as it has been described in septic shock and after mesenteric ischemia/ reperfusion. [25][26][27] Furthermore, that the flow pattern (pulsatile, nonpulsatile) of our artificial organ perfusion system had also an effect on the intestinal microvascular blood flow cannot be excluded. 28,29 Altogether, a detectable injury of the mucosa and muscularis occurred as a result of a prolonged "low-flow ischemia" during SVP caused by a decreased overall intestinal blood flow (CT and SMA).…”

Microcirculatory perfusion shift in the gut wall layers induced by extracorporeal circulation

“…1,11 Hence, ECC may induce a variety of pathologic phenomena that are still unclear and may possibly be triggered by a suboptimal microperfusion of the intestinal tissue. The porcine model by Sack and Hagl, 12 which creates a flow of 50% by ECC and 50% by the normal heart beat, demonstrated a drop in blood cell velocity in small vessels of the small intestine muscular layer. 12 Whether this phenomenon is the same in a small intestine fully perfused by ECC is unclear.…”

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

“…In one previous experimental study, CPB induced microvascular perfusion injury despite the normal and stable macrohemodynamics [6] . Using intravital microscopy, Sack and Hagl [6] demonstrated arteriolar vasoconstriction and a reduction in blood cell velocities at the microvascular level. A notable reduction in capillary density was observed, but the underlying mechanism remained open [6] .…”

“…Using intravital microscopy, Sack and Hagl [6] demonstrated arteriolar vasoconstriction and a reduction in blood cell velocities at the microvascular level. 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] .…”

“…However, the fact that the SVR increase was more pronounced in the MPO+ group, with better mucosal oxygenation during reperfusion, suggests that the mucosal oxygenation may be affected by other factors than the oxygen content of the blood and total flow through the splanchnic microcirculation. One such factor could be a rapid reorganization of the capillary bed as demonstrated by Sack and Hagl [6] .…”