Norepinephrine and vital organ blood flow.
OBJECTIVE
To test whether norepinephrine (NE) infusion at 0.4 microg kg(-1) min(-1) adversely affects regional blood flow in the normal mammalian circulation.


METHODS
Randomized cross-over experimental animal study in a university-affiliated physiology institute.


METHODS
Six merino ewes.


METHODS
Staged insertion of transit-time flow probes around the ascending aorta and circumflex coronary, superior mesenteric and left renal arteries. In conscious animals with chronically embedded flow probes randomization to either 6 h of placebo (saline) or drug (NE at 0.4 microg kg(-1) min(-1)).


RESULTS
Compared to placebo, NE significantly increased mean arterial pressure (84.4 vs. 103.8 mmHg), heart rate (61.0 vs. 74.6 bpm) and cardiac output (3.76 vs. 4.78 l/min). These changes were associated with an increase in coronary blood flow (24.2 vs. 37.4 ml/min) and renal blood flow (215.2 vs. 282.0 ml/min) but no change in mesenteric blood flow. The increase in renal and coronary blood flow was associated with an increase in regional conductance (regional vasodilatation), while mesenteric conductance fell (mesenteric vasoconstriction). Urine output (91+/-17 vs. 491+/-360 ml/h) and creatinine clearance (61+/-18 vs. 89+/-12 ml/min) increased during NE infusion.


CONCLUSIONS
NE infusion does not induce vital organ ischaemia in the normal mammalian circulation. Furthermore, it results in a significant increase in coronary and renal blood flow with a concomitant improvement in urine output and creatinine clearance.
Di Giantomasso
David
D
Department of Intensive Care, Austin and Repatriation Medical Centre, Heidelberg, Victoria 3084, Australia.
May
Clive N
CN
Bellomo
Rinaldo
R
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002302:Cardiac Output / Q000187:drug effects; D003326:Coronary Circulation / Q000187:drug effects*; D018592:Cross-Over Studies; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D007262:Infusions, Intravenous; D009638:Norepinephrine / Q000494:pharmacology*; D012039:Regional Blood Flow / Q000187:drug effects; D012079:Renal Circulation / Q000187:drug effects*; D012756:Sheep; D018709:Statistics, Nonparametric
D009638:Norepinephrine