Assessment of hepatic ischemia-reperfusion injury by simultaneous measurement of tissue pO2, pCO2, and pH.
BACKGROUND
The objective of this study was to determine whether the simultaneous measurement of tissue pH, pCO(2), and pO(2) with a multiple-parameter fiberoptic sensor (Paratrend 7) can be used for continuous monitoring of hepatic microperfusion in a pig model of hepatic ischemia given endothelin(A) receptor antagonist (ET(A)-RA) or isotonic saline.


METHODS
Fourteen anesthetized swine were subjected to 2 h of hepatic vascular exclusion. The animals were randomized into two groups: control group (n = 7, saline solution iv) and therapy group (n = 7, ET(A)-RA). For evaluation of ischemia-reperfusion injury, the data of the multiple-parameter sensor (pO(2para), pCO(2para), and pH(para)) were compared with partial oxygen pressure in tissue (p(ti)O(2)), laser Doppler flow, and systemic hemodynamic, metabolic data, and time course of transaminases.


RESULTS
In the control group 30 and 60 min after reperfusion, the following values were measured: p(ti)O(2): 34.0 +/- 8.6 / 36.3 +/- 7.0 mm Hg (P < 0.05 vs. preop.: 49.8 +/- 12.1 mm Hg), laser Doppler area: 133.3 +/- 23.2 / 156.4 +/- 15.4 (P < 0.05 vs. preop.: 215.9 +/- 14.8). Animals in the therapy group revealed significantly improved values (p(ti)O(2): 54.0 +/- 8.6 / 58.1 +/- 7.8 mm Hg, laser Doppler: 210.2 +/- 38.5 / 225.2 +/- 21.3; P < 0.05). Using the Paratrend, also an improvement in the therapy group was seen 30 and 60 min after reperfusion. The values showed a strong correlation with p(ti)O(2) (r = 0.895; P < 0.05) and laser Doppler flow (r = 0.807; P < 0.05). In the treatment group, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and glutamate dehydrogenase (GLDH) were reduced 6 and 18 h after reperfusion, respectively, indicating hepatoprotection by the therapy (P < 0.05 vs. control).


CONCLUSIONS
The Paratrend sensor offers the opportunity to study postischemic organ hemodynamics through the simultaneous measurement of interstitial pH, pCO(2), and pO(2) in a small tissue region. This method offers a prognostic tool for the study of the effects of experimental vasoactive therapy on liver microcirculation and perspectives for continuous monitoring of human liver microperfusion after liver surgery and trauma.
Uhlmann
Dirk
D
2nd Department of Surgery, University of Leipzig, 04103, Leipzig, Germany. Uhld@medizin.uni-leipzig.de
Pietsch
Uta Carolin
UC
Ludwig
Stefan
S
Hess
Jochen
J
Armann
Barbara
B
Gaebel
Gabor
G
Escher
Evelyn
E
Schaffranietz
Lutz
L
Tannapfel
Andrea
A
Fiedler
Martin
M
Hauss
Johann
J
Witzigmann
Helmut
H
D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D001219:Aspartate Aminotransferases / Q000097:blood; D002245:Carbon Dioxide / Q000378:metabolism*; D005260:Female; D005969:Glutamate Dehydrogenase / Q000097:blood; D006499:Hepatic Artery / Q000473:pathology; D006863:Hydrogen-Ion Concentration; D017078:Laser-Doppler Flowmetry; D008099:Liver / Q000378:metabolism / Q000473:pathology*; D008833:Microcirculation; D010100:Oxygen / Q000378:metabolism*; D010313:Partial Pressure; D011169:Portal Vein / Q000473:pathology; D044022:Receptor, Endothelin A / Q000378:metabolism / Q000502:physiology*; D015427:Reperfusion Injury; D013552:Swine; D013997:Time Factors
D044022:Receptor, Endothelin A; D002245:Carbon Dioxide; D005969:Glutamate Dehydrogenase; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; D010100:Oxygen