Heart Rate and Blood Pressure Variability effects as a result of Oxygen and Nitrous Oxide Administration in the Anesthetized Mouse

This study examines the effects of changing oxygen fractional inspiration ratio (FiO(2)), and nitrous oxide (N2O) for the improvement of cardiovascular control of mean arterial blood pressure (MAP) and heart rate (HR) in C57BL/6 mice under isoflurane anesthesia (1.5%) for up to 90 minutes post-induction. Heart rate variability (HRV) indices are also quantified under these conditions. The results indicate that changing the FiO(2) does result in lower MAP and HR values compared to the case of N2O (50%) administration to the isoflurane gas mixture. HRV indices declined over the course of all anesthetic regimens, suggesting a decrease in parasympathetic tone. We conclude that the most optimal anesthetic condition is achieved when N2O (50%) is added to the gas mixture.