[Influence of clonidine-induced systemic sympathicolysis on oxygenation and perfusion of the liver. Investigations with healthy pigs under general anesthesia].
BACKGROUND
Increased sympathetic nervous activity which induces vasoconstriction and decreases perfusion may be an underlying mechanism behind the development of perioperative liver damage. This animal study was designed to assess how clonidine-induced systemic sympathicolysis affects liver oxygenation with respect to induced hypotension and vasodilatation under physiological conditions.


METHODS
Following ethical approval 17 anesthetized and acutely instrumented pigs were randomly assigned to 2 groups. Group 1 consisted of 8 animals receiving intravenous clonidine (2 microg x kg(-1) bolus and 2 microg x kg(-1) x h(-1) for induction of sympathicolysis and group 2 consisted of 9 animals serving as controls. After obtaining baseline values, measurements were repeated 90 and 250 min after starting to reduce systemic sympathetic nervous activity.


RESULTS
Clonidine-induced systemic sympathicolysis was associated with decreased mean arterial blood pressure, cardiac output and heart rate. Portal venous and hepatic arterial blood flow, oxygen delivery to the liver, oxygen uptake and liver tissue oxygen partial pressure remained unchanged. The plasma indocyanine green disappearance rate increased.


CONCLUSIONS
We concluded that despite decreased mean arterial pressure and cardiac output, clonidine-induced systemic sympathicolysis did not affect liver oxygenation or perfusion.
Iber
T
T
Klinik und Poliklinik für Anästhesiologie und Intensivtherapie, Universität Rostock, Schillingallee 35, 18055 Rostock, Deutschland.
Roesner
J P
JP
Mutz
C
C
Werner
B
B
Peters
E
E
Brüderlein
K
K
Nöldge-Schomburg
G
G
Vagts
D A
DA
D000768:Anesthesia, General; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D003000:Clonidine / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects; D007208:Indocyanine Green; D007275:Injections, Intravenous; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008102:Liver Circulation / Q000187:drug effects*; D009638:Norepinephrine / Q000097:blood; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption / Q000187:drug effects* / Q000502:physiology; D011652:Pulmonary Circulation / Q000187:drug effects; D013552:Swine; D013565:Sympatholytics / Q000494:pharmacology*; D014661:Vasoconstriction / Q000187:drug effects / Q000502:physiology; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology
D013565:Sympatholytics; D007208:Indocyanine Green; D003000:Clonidine; D010100:Oxygen; D009638:Norepinephrine