Cerebral Blood Flow at 0.5 and 1.0 Minimal Alveolar Concentrations of Desflurane or Sevoflurane Compared with Isoflurane in Normoventilated Pigs

Abstract

Whether desflurane and sevoflurane have clinical advantages over isoflurane in neuroanesthesia is much debated. A porcine model was used for comparison of desflurane and sevoflurane with isoflurane with respect to their cerebrovascular effects. The minimal alveolar concentration (MAC) of each of the three agents was first determined in a standardized manner in six domestic juvenile pigs to enhance comparison reliability. Six other pigs were then anesthetized with isoflurane, desflurane, and sevoflurane, given in sequence to each pig in an even crosswise order with the first agent also used to maintain anesthesia during surgical preparation. Cerebral blood flow (CBF) was calculated from the clearance curve of intraarterially injected 133Xe. The mean arterial pressure (MAP) was invasively monitored. The estimated cerebrovascular resistance (CVRe) was calculated by dividing MAP with CBF, thereby approximating the cerebral perfusion pressure with MAP. For both MAC levels, the trend for CBF was desflurane > isoflurane > sevoflurane, and the trend for MAP and CVRe was sevoflurane > isoflurane > desflurane. Statistical comparison of desflurane and sevoflurane with isoflurane with respect to CBF and MAP revealed two statistically significant differences-namely, that CBF at 1.0 MAC desflurane was 17% higher than CBF at 1.0 MAC isoflurane (P =.0025) and that MAP at 1.0 MAC sevoflurane was 16% higher than MAP at 1.0 MAC isoflurane (P =.011). Consequently, in this study at normocapnia, these agents did not seem to differ much in their cerebral vasodilating effects at lower doses. At higher doses, however, desflurane, in contrast to sevoflurane, was found to induce more cerebral vasodilation than isoflurane.

Minimum alveolar concentrations and hemodynamic effects of two different preparations of sevoflurane in pigs

“…In the study of Hecker,10 where the pigs had almost the same weight and were submitted to the same nociceptive stimulation as in the present study, the MAC was lower, which may have been due to the previous use of azaperone and propofol. Holmström and Åkeson,13 in animals weighing 20.1± 0.7 kg, obtained a MAC of 4.4 90 minutes after propofol administration, which is the same value reported in the present investigation. On the other hand, Moeser et al,12 studying animals weighing 19 ±0.4 kg and with no other agent than sevoflurane, obtained a MAC of 3.5±0.17.…”

“…These values are higher than most published reports, in which sevoflurane MAC values range between 2.1% and 4.4% in pigs 8–13…”

Influence of Ventilation Strategies and Anesthetic Techniques on Regional Cerebral Oximetry in the Beach Chair Position

“…The effect on rSO 2 due to interactions between inspired gas composition and anesthetic choice is of clinical interest, especially when comparing propofol to desflurane, the halogenated ether with the greatest potential for cerebral vasodilatation. 18 …”

Wpływ stopniowo narastających stężeń desfluranu na mózgowe ciśnienie perfuzyjne u królika

“…Likewise, the results of experiments in animal models [20,[31][32][33][34] are not explicit. According to studies on pigs, ICP and CBF increased after the use of desflurane under normocapnic conditions.…”