Effects of epinephrine on intestinal oxygen supply and mucosal tissue oxygen tension in pigs.
OBJECTIVE
To study the effects of increasing dosages of epinephrine given intravenously on intestinal oxygen supply and, in particular, mucosal tissue oxygen tension in an autoperfused, innervated jejunal segment.


METHODS
Prospective, randomized experimental study.


METHODS
Animal research laboratory.


METHODS
Domestic pigs.


METHODS
Sixteen pigs were anesthetized, paralyzed, and normoventilated. A small segment of the jejunal mucosa was exposed by midline laparotomy and antimesenteric incision. Mucosal oxygen tension was measured by using Clark-type surface oxygen electrodes. Microvascular hemoglobin oxygen saturation and microvascular blood flow (perfusion units) were determined by tissue reflectance spectrophotometry and laser-Doppler velocimetry. Systemic hemodynamics, mesenteric-venous acid-base and blood gas variables, and systemic acid-base and blood gas variables were recorded. Measurements were performed after a resting period and at 20-min intervals during infusion of increasing dosages of epinephrine (n = 8; 0.01, 0.05, 0.1, 0.5, 1, and 2 microg x kg(-1) x min(-1)) or without treatment (n = 8). In addition, arterial and mesenteric-venous lactate concentrations were measured at baseline and at 60 and 120 mins.


RESULTS
Epinephrine infusion led to significant tachycardia; an increase in cardiac output, systemic oxygen delivery, and oxygen consumption; and development of lactic acidosis. Epinephrine significantly increased jejunal microvascular blood flow (baseline, 267 +/- 39 perfusion units; maximum value, 443 +/- 35 perfusion units) and mucosal oxygen tension (baseline, 36 +/- 2.0 torr [4.79 +/- 0.27 kPa]; maximum value, 48 +/- 2.8 torr [6.39 +/- 0.37 kPa]) and increased hemoglobin oxygen saturation above baseline. Epinephrine increased mesenteric venous lactate concentration (baseline, 2.9 +/- 0.6 mmol x L(-1); maximum value, 5.5 +/- 0.2 mmol x L(-1)) without development of an arterial-mesenteric venous lactate concentration gradient.


CONCLUSIONS
Epinephrine increased jejunal microvascular blood flow and mucosal tissue oxygen supply at moderate to high dosages. Lactic acidosis that develops during infusion of increasing dosages of epinephrine is not related to development of gastrointestinal hypoxia.
Division of General and Surgical Intensive Care Medicine, Department of Anesthesia and Critical Care Medicine, The Leopold Franzens University of Innsbruck, Innsbruck, Austria.
N
N
Salak
W
W
Pajk
H
H
Knotzer
H
H
Hofstötter
B
B
Schwarz
A
A
Mayr
B
B
Labeck
R
R
Kafka
H
H
Ulmer
N
N
Mutz
W
W
Hasibeder
D000140:Acidosis, Lactic / Q000139:chemically induced; D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000818:Animals; D001783:Blood Flow Velocity / Q000187:drug effects; D004195:Disease Models, Animal; D004353:Drug Evaluation, Preclinical; D004837:Epinephrine / Q000494:pharmacology*; D006439:Hemodynamics / Q000187:drug effects; D007262:Infusions, Intravenous; D007413:Intestinal Mucosa / Q000098:blood supply* / Q000737:chemistry / Q000187:drug effects*; D007583:Jejunum / Q000098:blood supply* / Q000737:chemistry / Q000187:drug effects*; D017078:Laser-Doppler Flowmetry; D008833:Microcirculation / Q000187:drug effects*; D010100:Oxygen / Q000032:analysis*; D010101:Oxygen Consumption / Q000187:drug effects*; D011446:Prospective Studies; D011897:Random Allocation; D013053:Spectrophotometry; D013552:Swine; D014662:Vasoconstrictor Agents / Q000494:pharmacology*
D000316:Adrenergic alpha-Agonists; D000318:Adrenergic beta-Agonists; D014662:Vasoconstrictor Agents; D010100:Oxygen; D004837:Epinephrine