Effects of hemorrhage on gastrointestinal oxygenation.
OBJECTIVE
(1) To demonstrate that metabolic parameters are better indicators of tissue hypoxia than regional and whole oxygen consumption (VO(2)). (2) To compare intramucosal pH (pHi) in different gastrointestinal segments.


METHODS
Prospective, interventional study.


METHODS
Research laboratory at a university center.


METHODS
Fourteen anesthetized, mechanically ventilated dogs.


METHODS
Twenty milliliters per kilogram bleeding.


RESULTS
We placed pulmonary, aortic and mesenteric venous catheters, and an electromagnetic flow probe in the superior mesenteric artery, and gastric, jejunal and ileal tonometers to measure flows, arterial and venous blood gases and lactate, and intramucosal PCO(2). We calculated systemic and intestinal oxygen transport (DO(2)) and consumption (VO(2)), pHi and arterial minus intramucosal PCO(2) (DeltaPCO(2)). Then, we bled the dogs and repeated the measurements after 30 min. Systemic and intestinal DO(2) fell (26.0+/-7.3 versus 8.9+/-2.6 and 71.9+/-17.3 versus 24.6+/-9.6 ml/min per kg, respectively, p<0.0001). Systemic and intestinal VO(2) remained unchanged (5.5+/-1.3 versus 5.4+/-1.3 and 15.7+/-5.0 versus 14.9+/-5.3 ml/min per kg, respectively). Gastric, jejunal and ileal pHi (7.13+/-0.11 versus 6.96+/-0.17, 7.18+/-0.06 versus 6.97+/-0.15, 7.12+/-0.11 versus 6.94+/-0.14, p<0.05) and DeltaPCO(2) (21+/-13 versus 35+/-23, 15+/-5 versus 33+/-16, 23+/-17 versus 38+/-20, p<0.05) changed accordingly. Arterial and mesenteric venous lactate and their difference, rose significantly (1.7+/-0.9 versus 3.7+/-1.4 and 1.8+/-0.8 versus 4.3+/-1.5 mmol/l, 0.1+/-0.6 versus 0.6+/-0.7 mmol/l, p<0.05).


CONCLUSIONS
During hemorrhage, systemic and intestinal VO(2) remained stable. However, hyperlactatemia and intramucosal acidosis evidenced anaerobic metabolism. pHi changes paralleled in the three intestinal segments.
Dubin
A
A
Cátedra de Farmacología, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, calle 42 No 577, (1900) La Plata, Argentina. adee@infovia.com.ar
Estenssoro
E
E
Murias
G
G
Canales
H
H
Sottile
P
P
Badie
J
J
Barán
M
M
Pálizas
F
F
Laporte
M
M
Rivas Díaz
M
M
D000704:Analysis of Variance; D000818:Animals; D002245:Carbon Dioxide / Q000097:blood; D004285:Dogs; D005753:Gastric Mucosa / Q000098:blood supply / Q000378:metabolism*; D006439:Hemodynamics; D006863:Hydrogen-Ion Concentration; D007082:Ileum / Q000378:metabolism; D007413:Intestinal Mucosa / Q000098:blood supply / Q000378:metabolism*; D007583:Jejunum / Q000378:metabolism; D019344:Lactic Acid / Q000097:blood; D010100:Oxygen / Q000378:metabolism*; D010313:Partial Pressure; D011446:Prospective Studies; D012771:Shock, Hemorrhagic / Q000150:complications / Q000378:metabolism*; D013152:Splanchnic Circulation
D002245:Carbon Dioxide; D019344:Lactic Acid; D010100:Oxygen