Isoflurane For Maintenance Of Anesthesia Research Articles

Comparison of recoveries from halothane vs isoflurane anesthesia in horses

Summary Recovery from isoflurane anesthesia was shorter, with no difference in quality, compared with halothane anesthesia in 2 groups of horses. In 1 group, 12 horses scheduled for elective arthroscopy were randomly assigned to receive halothane or isoflurane for maintenance of anesthesia during surgery. In the other group, 6 horses received anesthesia only, on 2 occasions, with halothane on 1 occasion, and isoflurane on the other. Difference in the quality of recovery was not seen between isoflurane and halothane anesthesia in either group. In the group that had surgery, recovery to sternal position was significantly shorter when isoflurane was used. In the group not treated surgically, recovery to sternal and standing positions was significantly shorter with isoflurane.

End-Tidal Concentrations of Halothane and Isoflurane During Induction of Anaesthesia in Young and Elderly Patients

Twenty-two young (18–32 yr) and 22 healthy elderly (60–80 yr) patients received either halothane or isoflurane for maintenance of anaesthesia during controlled ventilation. Endtidal fractional concentrations (FE) of the agents were measured for 20 min after their introduction into inspired gas and the increase in end-tidal concentrations of the two agents was compared during induction of anaesthesia using the ratios of FE to the inspired fraction (F1). FE: F1 ratios for isoflurane were higher than those for halothane in both young and elderly patients, confirming that equilibration of end-tidal with inspired concentration occurs more rapidly with isoflurane than with halothane in both age groups. FE: F1 ratios for isoflurane became significantly lower in the elderly than in the young after 15 min administration of isoflurane. This suggests slower induction of anaesthesia in the elderly if equipotent concentrations of isoflurane are used; the clinical significance of this difference is probably small. Mean FE: F1 ratios for halothane in elderly patients were similar to those in the young throughout induction of anaesthesia.

END-TIDAL CONCENTRATIONS OF HALOTHANE AND ISOFLURANE DURING INDUCTION OF ANAESTHESIA IN YOUNG AND ELDERLY PATIENTS

Twenty-two young (18-32 yr) and 22 healthy elderly (60-80 yr) patients received either halothane or isoflurane for maintenance of anaesthesia during controlled ventilation. End-tidal fractional concentrations (FE) of the agents were measured for 20 min after their introduction into inspired gas and the increase in end-tidal concentrations of the two agents was compared during induction of anaesthesia using the ratios of FE to the inspired fraction (FI). FE:FI ratios for isoflurane were higher than those for halothane in both young and elderly patients, confirming that equilibration of end-tidal with inspired concentration occurs more rapidly with isoflurane than with halothane in both age groups. FE:FI ratios for isoflurane became significantly lower in the elderly than in the young after 15 min administration of isoflurane. This suggests slower induction of anaesthesia in the elderly if equipotent concentrations of isoflurane are used; the clinical significance of this difference is probably small. Mean FE:FI ratios for halothane in elderly patients were similar to those in the young throughout induction of anaesthesia.