Dopamine-1-receptor stimulation and mucosal tissue oxygenation in the porcine jejunum.
OBJECTIVE
To evaluate the effects of dopamine-1-receptor stimulation on intestinal mucosal tissue oxygenation.


METHODS
Prospective, experimental, controlled trial.


METHODS
Animal research laboratory.


METHODS
Anesthetized domestic pigs (30 to 45 kg).


METHODS
A small segment of the jejunal mucosa and serosa was exposed by midline laparotomy and antimesenteric incision. Fenoldopam, a selective dopamine-1-receptor agonist, was infused in steps, exponentially increasing from 0.6 to 9.6 micrograms/kg/min via a central venous catheter (n = 8, fenoldopam group), whereas a second group (n = 6, saline group) was only given the solvent.


RESULTS
Systemic hemodynamics as well as systemic and jejunal acid base and blood gas variables were measured using an arterial catheter, a thermodilution pulmonary artery catheter, and a jejunal venous catheter. Jejunal mucosal and serosal tissue PO2 were measured by means of Clark-type surface oxygen electrodes. Oxygen saturation and relative concentration of mucosal microvascular hemoglobin were measured by means of tissue reflectance spectrophotometry. In the fenoldopam group, systemic oxygen delivery (12.5 +/- 0.8 mL/kg/min at baseline) increased by 56% (p < .001) above baseline values. Mean arterial pressure remained unchanged. Fenoldopam produced a 51% increase in mucosal PO2 (23.8 +/- 2.8 torr [3.2 +/- 0.4 kPa] at baseline; p < .001) and a 31% increase in mucosal hemoglobin oxygen saturation (55.4 +/- 8.3% at baseline; p < .001), but not change in serosal PO2 (58 +/- 4.8 torr [7.7 +/- 0.6 kPa] at baseline).


CONCLUSIONS
Fenoldopam improves tissue oxygenation of the porcine jejunum in a dose-related manner. This effect is limited to the inner mucosal layer. Dopamine-1-receptor agonists should be evaluated in patients presenting with signs of intestinal mucosal ischemia.
Germann
R
R
Department of Anesthesia and General Intensive Care Medicine, University of Innsbruck, Austria.
Hasibeder
W
W
Haisjackl
M
M
Sparr
H
H
Luz
G
G
Pernthaler
H
H
Friesenecker
B
B
Bonatti
J
J
Gruber
E
E
Schwarz
B
B
D000818:Animals; D004305:Dose-Response Relationship, Drug; D018818:Fenoldopam / Q000494:pharmacology*; D006439:Hemodynamics / Q000187:drug effects; D007413:Intestinal Mucosa / Q000098:blood supply / Q000187:drug effects* / Q000378:metabolism; D007583:Jejunum / Q000098:blood supply / Q000187:drug effects* / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption / Q000187:drug effects; D011446:Prospective Studies; D017447:Receptors, Dopamine D1 / Q000187:drug effects* / Q000378:metabolism; D013552:Swine
D017447:Receptors, Dopamine D1; D018818:Fenoldopam; D010100:Oxygen