Effects of norepinephrine on tissue perfusion in a sheep model of intra-abdominal hypertension

Abstract

BackgroundThe aim of the study was to describe the effects of intra-abdominal hypertension (IAH) on regional and microcirculatory intestinal blood flow, renal blood flow, and urine output, as well as their response to increases in blood pressure induced by norepinephrine.MethodsThis was a pilot, controlled study, performed in an animal research laboratory. Twenty-four anesthetized and mechanically ventilated sheep were studied. We measured systemic hemodynamics, superior mesenteric and renal blood flow, villi microcirculation, intramucosal-arterial PCO2, urine output, and intra-abdominal pressure. IAH (20 mm Hg) was generated by intraperitoneal instillation of warmed saline. After 1 h of IAH, sheep were randomized to IAH control (n = 8) or IAH norepinephrine (n = 8) groups, for 1 h. In this last group, mean arterial pressure was increased about 20 mm Hg with norepinephrine. A sham group (n = 8) was also studied. Fluids were administered to prevent decreases in cardiac output. Differences between groups were analyzed with two-way repeated measures of analysis of variance (ANOVA).ResultsAfter 2 h of IAH, abdominal perfusion pressure decreased in IAH control group compared to IAH norepinephrine and sham groups (49 ± 11, 73 ± 11, and 86 ± 15 mm Hg, P < 0.0001). There were no differences in superior mesenteric artery blood flow, intramucosal-arterial PCO2, and villi microcirculation among groups. Renal blood flow (49 ± 30, 32 ± 24, and 102 ± 45 mL.min−1.kg−1, P < 0.0001) and urinary output (0.3 ± 0.1, 0.2 ± 0.2, and 1.0 ± 0.6 mL.h−1.kg−1, P < 0.0001) were decreased in IAH control and IAH norepinephrine groups, compared to the sham group.ConclusionsIn this experimental model of IAH, the gut and the kidney had contrasting responses: While intestinal blood flow and villi microcirculation remained unchanged, renal perfusion and urine output were severely compromised.Electronic supplementary materialThe online version of this article (doi:10.1186/s40635-015-0046-1) contains supplementary material, which is available to authorized users.

Effect of intraabdominal hypertension on splanchnic blood flow in children with appendicular peritonitis

“…[ 5 ] Likewise, in another study by Ferrara et al there was no correlation between APP and mesenteric blood flow in sheep with IAH of 20 mm Hg. [ 13 ] We also did not find statistically significant correlation between APP and BFI SMA or BFI PV , so our data confirm Ferrara's et al study results.…”

“…In contrast, Ferrara et al have not found differences in BF SMA between sheep with IAH (20 mm Hg for 2 hours) and sheep with normal IAP. [ 13 ] This can be attributed to small sample size in Ferrara's et al study.…”

Abdominal pressure and gastrointestinal function: an inseparable couple?

“…IAH causes a dose-related decrease in abdominal blood flow including the mesenteric artery, the hepatic artery, the portal veins and the renal artery [46,[50][51][52][53][54]. The threshold of IAP causing reductions in regional abdominal blood flow has been shown to vary between 8 and 20 mm Hg and probably reflects the different measurement techniques used (Doppler flow probes, transit-time flow probes) and subjects studied (animals, humans) [46,53].…”

“…Ferrara et al [54] studied the hemodynamic effect of NA in a healthy sheep model of IAH. While an IAP of 20 mm Hg did not change cardiac output or blood pressure, it decreased superior mesenteric and renal artery blood flow.…”

“…Studies examining the splanchnic effect of vasoactive drugs: 1) are most often performed in animals and not in humans [54,[76][77][78][79][80][81][82]; 2) frequently compare such an effect in septic and non-septic conditions [76][77][78]; and 3) are rarely performed in the setting of IAH [54,81,82].…”