The effect of norepinephrine and dobutamine on bladder epithelial oxygen tension.
OBJECTIVE
To assess the effects of two contrasting vasoactive agents (dobutamine [DOB] and norepinephrine [NE]) on (1) global and regional cardiorespiratory variables, (2) acid base status, and (3) bladder epithelial oxygen tension (BEOT), a putative marker of organ perfusion.


METHODS
Measurement of aortic blood flow (ABF) and renal blood flow (RBF), mean arterial blood pressure, arterial blood gases, and BEOT were made during infusion of placebo and varying doses of DOB and NE.


METHODS
Medical school laboratory.


METHODS
Eighteen anesthetized, spontaneously breathing, male Sprague-Dawley rats divided into three groups.


METHODS
Two groups were allocated to receive escalating doses of DOB (to 40 micrograms/kg/min) or NE (to achieve a 50% change in any hemodynamic variable). The drug therapy was then discontinued for 15 min and restarted at the previous maximum dose. A third group received 0.9% saline solution at the same infusion rate (16 mL/kg/h).


RESULTS
There was a dose-related increase in mean blood pressure with NE and fall with DOB. Compared with control values, NE had no effect on ABF but decreased RBF significantly whereas DOB significantly increased ABF but had no effect on RBF. Base excess and BEOT decreased significantly and in parallel with both agents, more so with NE.


CONCLUSIONS
Despite their different macrocirculatory effects, DOB and NE both produced a significant but reversible fall in BEOT and a metabolic acidosis. BEOT shows potential as a monitor of the effectiveness of organ perfusion.
Rosser
D M
DM
Bloomsbury Institute of Intensive Care Medicine, Department of Medicine, University College London Medical School, United Kingdom.
Stidwill
R P
RP
Millar
C G
CG
Singer
M
M
D000818:Animals; D004280:Dobutamine / Q000494:pharmacology*; D004848:Epithelium / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology*; D010100:Oxygen / Q000097:blood*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow / Q000187:drug effects; D001743:Urinary Bladder / Q000187:drug effects* / Q000502:physiology; D014662:Vasoconstrictor Agents / Q000494:pharmacology*
D014662:Vasoconstrictor Agents; D004280:Dobutamine; D010100:Oxygen; D009638:Norepinephrine