AJP - Heart and Circulatory Physiology, Vol 271, Issue 5 1849-H1855, Copyright © 1996 by American Physiological Society
Effects of hemodilution on gastric regional perfusion and intramucosal pH
M. Kleen, O. Habler, J. Hutter, A. Podtschaske, M. Tiede, G. Kemming, M. Welte, C. Corso and K. Messmer
Institute for Surgical Research, University of Munich, Germany.
Acute normovolemic hemodilution (ANH) has been shown to be a cost-effective
method of reducing allogenic blood transfusion during elective surgery. ANH
has been implicated with impaired oxygenation in isolated canine gastric
flaps. The present study was designed to investigate the effects of ANH on
gastric mucosal oxygenation using a model closely imitating the clinical
situation. Sixteen splenectomized anesthetized beagles were isovolemically
hemodiluted to a hematocrit of 20 +/- 1% (6% hydroxyethyl starch; mol wt
200,000; substitution ratio 0.45-0.55). Blood volume (indocyanine green),
cardiorespiratory parameters, gastric intramucosal pH (pHi), and gastric
regional blood flow (radioactive microspheres; 15 microns) were measured
before and after ANH. Results: blood volume was unchanged (87 +/- 8 ml/kg
before and 88 +/- 7 ml/kg after ANH). Median total gastric mucosal blood
flow at baseline was 0.51 +/- 0.35 ml.min-1.g-1 and did not change
significantly upon ANH. The mean pHi was 7.29 +/- 0.05 before and 7.28 +/-
0.05 after hemodilution. There was a homogenization of blood flow
distribution in gastric mucosa. Severe hemodilution to a hematocrit of 20%
does not impair gastric mucosal oxygenation and poses no risk to gastric
mucosal integrity.
