Effects of systemic arterial hypoperfusion on splanchnic hemodynamics and hepatic arterial buffer response in pigs

Abstract

The hepatic arterial buffer response (HABR) tends to maintain liver blood flow under conditions of low mesenteric perfusion. We hypothesized that systemic hypoperfusion impairs the HABR. In 12 pigs, aortic blood flow was reduced by cardiac tamponade to 50 ml. kg(-1). min(-1) for 1 h (short-term tamponade) and further to 30 ml. kg(-1). min(-1) for another hour (prolonged tamponade). Twelve pigs without tamponade served as controls. Portal venous blood flow decreased from 17 +/- 3 (baseline) to 6 +/- 4 ml. kg(-1). min(-1) (prolonged tamponade; P = 0.012) and did not change in controls, whereas hepatic arterial blood flow decreased from 2 +/- 1 (baseline) to 1 +/- 1 ml. kg(-1). min(-1) (prolonged tamponade; P = 0.050) and increased from 2 +/- 1 to 4 +/- 2 ml. kg(-1). min(-1) in controls (P = 0.002). The change in hepatic arterial conductance (DeltaC(ha)) during acute portal vein occlusion decreased from 0.1 +/- 0.05 (baseline) to 0 +/- 0.01 ml. kg(-1). min(-1). mmHg(-1) (prolonged tamponade; P = 0.043). In controls, DeltaC(ha) did not change. Hepatic lactate extraction decreased, but hepatic release of glutathione S-transferase A did not change during cardiac tamponade. In conclusion, during low systemic perfusion, the HABR is exhausted and hepatic function is impaired without signs of cellular damage.

Jejunal luminal microdialysate lactate in cardiac tamponade – effect of low systemic blood flow on gut mucosa

“…The 12 animals in the present experiment were included in a larger study (n=24), which focused on hepatic arterial buffer response [18]. Gut luminal microdialysis was performed only in these 12 animals, which represent one of the two blocks in the block randomization protocol of the larger series.…”

Hypoxic Hepatopathy: Pathophysiology and Prognosis

“…Profound hepatic hypoperfusion (66% reduction of portal flow during ischemia and 80% reduction in hepatic artery flow during reperfusion) producing temporary acute hepatic dysfunction has been found to follow intestinal ischemia-reperfusion injury in the rat (40). In the pig model the reduction of aortic blood flow by cardiac tamponade can exhaust the hepatic arterial buffer response resulting in hepatic dysfunction without signs of cellular damage (41).…”

Effects of cardiac preload reduction and dobutamine on hepatosplanchnic blood flow regulation in porcine endotoxemia

“…Global hepatic blood flow is supposed to be relatively protected when gut blood flow decreases because hepatic arterial flow increases when portal venous flow decreases (the hepatic arterial buffer response, HABR) (25, 26). However, evidence suggests that the HABR is diminished or even abolished during endotoxemia (1) and when gut blood flow becomes very low (19,31).The HABR is usually assessed by decreasing superior mesenteric or portal venous blood flow and measurement of the associated changes in hepatic arterial blood flow and pressure. The clinical correlates to this maneuver, mesenteric embolism or acute portal vein thrombosis, are rare events.…”

“…Global hepatic blood flow is supposed to be relatively protected when gut blood flow decreases because hepatic arterial flow increases when portal venous flow decreases (the hepatic arterial buffer response, HABR) (25, 26). However, evidence suggests that the HABR is diminished or even abolished during endotoxemia (1) and when gut blood flow becomes very low (19,31).…”