Purpose:To assess the influence of isoflurane and pentobarbital anesthesia and the carrier gases on myocardial blood flow (MBF) in the rat heart in vivo.
Materials and Methods:MBF was quantified in vivo using arterial spin-labeling (ASL) magnetic resonance imaging (MRI). Left ventricular (LV) function was estimated during the same experiment using cine-MRI. Thirty-four male Wistar-Kyoto rats were divided in four groups, one anesthetized with isoflurane in oxygen:nitrous oxide mix (ISO), the three others with intraperitoneal pentobarbital, and breathing either room air (PB), oxygen:nitrous oxide (PB ϩ N 2 O), or oxygen:nitrogen (PB ϩ N 2 ).Results: MBF was significantly higher in the ISO and PB ϩ N 2 O groups vs. PB and in ISO vs. PB ϩ N 2 , with the following respective MBF values: ISO, 5.9 Ϯ 1.1; PB, 4.0 Ϯ 0.8; PB ϩ N 2 O, 5.1 Ϯ 1.4; and PB ϩ N 2 , 4.6 Ϯ 0.8 mL/g/minute, mean Ϯ SD. Ejection fractions were reduced by 10% in PB and PB ϩ N 2 O rats vs. ISO rats. Cardiac output (CO) and index (CI) were 25 to 30% lower in all rats anesthetized with pentobarbital than with isoflurane.
Conclusion:Isoflurane and nitrous oxide induce a higher MBF than pentobarbital. Isoflurane also induces a higher ejection fraction in healthy rats.