Cardioprotection against reperfusion injury is maximal with only two minutes of sevoflurane administration in rats.
OBJECTIVE
Volatile anesthetics can protect the heart against reperfusion injury. When sevoflurane is given for the first 15 min of reperfusion, a concentration corresponding to one minimum alveolar concentration (MAC) provides a maximum protective effect. The present study addresses the question of how long sevoflurane has to be administered to achieve the best cardioprotection.


METHODS
Chloralose anesthetized rats were subjected to a 25-min occlusion of a major coronary artery, followed by 90 min of reperfusion. During the initial phase of reperfusion, an end-tidal concentration of 2.4 vol.% of sevoflurane (1 MAC) was given for two (n = 8), five (n = 8) or ten minutes (n = 7). Seven rats served as untreated controls. We measured left ventricular (LV) pressure, mean aortic pressure and infarct size (triphenyltetrazolium staining).


RESULTS
Administration of sevoflurane for two minutes resulted in the greatest reduction of infarct size to 15% (8-22 [mean (95% confidence interval)] of the area at risk compared with controls [51 (47-55) %, P < 0.001]. Five or ten minutes of sevoflurane administration reduced infarct size to 26 (18-34) and 26 (18-35) % [P < 0.05], respectively. The cardiodepressant effect of sevoflurane varied with the duration of its administration: LV dP/dt was reduced from 6332 mmHg x sec(-1) (5771-6894) during baseline to 4211 mmHg x sec(-1) (3031-5391), 3811 mmHg x sec(-1) (2081-5540) and 3612 mmHg x sec(-1) (2864-4359) after two, five and ten minutes of reperfusion, respectively.


CONCLUSIONS
Administration of 1 MAC sevoflurane for the first two minutes of reperfusion effectively protects the heart against reperfusion injury in rats in vivo. A longer administration time had lesser cardioprotective effects in this experimental model.
Obal
Detlef
D
Klinik für Anaesthesiologie, Universitätsklinikum Düsseldorf, Germany.
Scharbatke
Horst
H
Barthel
Holger
H
Preckel
Benedikt
B
Müllenheim
Jost
J
Schlack
Wolfgang
W
D000704:Analysis of Variance; D018685:Anesthetics, Inhalation / Q000008:administration & dosage / Q000627:therapeutic use; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002316:Cardiotonic Agents / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D006339:Heart Rate / Q000187:drug effects; D008738:Methyl Ethers / Q000008:administration & dosage / Q000627:therapeutic use*; D009203:Myocardial Infarction / Q000517:prevention & control*; D015428:Myocardial Reperfusion Injury / Q000517:prevention & control*; D051381:Rats; D017208:Rats, Wistar; D000077149:Sevoflurane; D013997:Time Factors; D014655:Vascular Resistance / Q000187:drug effects
D018685:Anesthetics, Inhalation; D002316:Cardiotonic Agents; D008738:Methyl Ethers; D000077149:Sevoflurane