[Direct observation of microcirculation in isoflurane anesthesia].
The effects of anaesthesia with 1.0 vol% isoflurane or 0.7 vol% halothane on the microcirculation were studied in the dorsal skin fold chamber of 15 awake Syrian Golden hamsters. To avoid relative hypovolaemia hydroxyethyl starch (HES 450/0.7) was infused to keep the CVP at baseline level. Arterial blood gas values did not change with either of the anaesthetic agents. Mean arterial pressure decreased significantly with isoflurane to 79% of baseline. Small arteries (25-100 micron) did not exhibit any alterations of diameters in both groups, whereas arterioles (less than 25 micron) constricted with isoflurane from 15.5 to 13.3 micron (15 min) and to 12.0 micron (60 min). 10 min after stopping isoflurane further vasoconstriction was regularly noticed (from 51.0 resp. 15.5 micron to 36.6 resp. 9.7 micron) which did not occur after halothane. Spontaneous arteriolar vasomotion was abolished by halothane, but not by isoflurane; in two animals its amplitude increased. Capillary density rose with both anaesthetics: 9.1% (15 min) resp. 9.0% (60 min) with halothane, 14.0% resp. 17.3% with isoflurane. Local tissue pO2 measured in 6 additional hamsters increased during isoflurane from 16.4 to 22.8 mmHg (15 min) and 19.8 mmHg (60 min). It is concluded that isoflurane is less detrimental to local perfusion control than halothane. The preserved regulatory capacity results in a redistribution of microvascular flow and an improvement of oxygen supply to the dorsal skin fold chamber despite arterial hypotension.
D000769:Anesthesia, Inhalation; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D006224:Cricetinae; D006221:Halothane / Q000494:pharmacology; D007530:Isoflurane / Q000494:pharmacology*; D008647:Mesocricetus; D008833:Microcirculation / Q000187:drug effects*; D010100:Oxygen / Q000097:blood; D012867:Skin / Q000098:blood supply*
D007530:Isoflurane; D010100:Oxygen; D006221:Halothane
Direkte Beobachtung der Mikrozirkulation unter Isofluran-Anästhesie.