The effects of halothane and isoflurane on the phosphoenergetic state of the liver during hemorrhagic shock in rats: an in vivo 31P nuclear magnetic resonance spectroscopic study.

We studied the effects of halothane versus isoflurane on the phosphoenergetic state and intracellular pH (pHi) of the rat liver using in vivo 31P nuclear magnetic resonance (NMR) spectroscopy during and after hemorrhagic shock. Seventeen rats were anesthetized with 1 minimum alveolar anesthetic concentration of halothane or isoflurane. The mean arterial blood pressure was reduced to 40 mm Hg and maintained at this level for 45 min by withdrawing blood from the common carotid artery. The shed blood was then returned slowly. In vivo 31P NMR spectra were consecutively collected throughout the study. The phosphoenergetic state of the liver was evaluated from the changes in adenosine triphosphate (ATP) and inorganic phosphate (P(i)) levels. pHi was calculated from the chemical shifts of P(i) and alpha-ATP peaks. During hemorrhagic shock, beta-ATP decreased to 35% and 45%, and P(i) increased to 300% and 230% of their initial values in the halothane and isoflurane groups, respectively. Intracellular acidosis was more severe in the halothane group. The recoveries of beta-ATP and P(i) were better in the isoflurane group. Halothane showed a more detrimental effect than isoflurane on the hepatic phosphoenergetic level during and after hemorrhagic shock.