Hemodynamics and catecholamines in anesthesia with different concentrations of xenon

Background: During xenon anesthesia with inspiratory concentrations of 1 MA C, no adverse effects on cardiovascular stability were reported until prese nt. During different surgical procedures, small and not significant increas es in plasma norepinephrine and not significant decreases in plasma epineph rine concentrations were observed. Plasma dopamine concentrations remained unaltered. Excluding the influence of different surgical stimuli and to inv estigate the influence of different concentrations of xenon, we conducted a study in an experimental animal model during standardized surgical stimula tion. Methods: Twenty-eight pigs were randomly assigned to one of four groups: To tal intravenous anesthesia (TIVA) as control group, xenon anesthesia with c oncentrations of 30%, 50% or 70%. Open dissection of femoral artery was use d as surgical stimulus. Hemodynamic parameters were measured on-line by art erial and Swan Ganz catheter. The depth of anesthesia was monitored using t he spectral edge frequency SEF 95. Plasma concentrations of dopamine, norep inephrine and epinephrine were measured by High-Performance-Liquid-Chromato graphy (HPLC). Results: All hemodynamic parameters were not significantly changed during x enon anesthesia. Plasma dopamine and norepinephrine concentrations remained within normal limits. Compared to controls, epinephrine concentrations wer e significantly reduced in all xenon groups. Conclusions: Xenon anesthesia with inspiratory concentrations between 30% a nd 70% is associated with a high degree of cardiovascular stability. Signif icant reduction of epinephrine levels seems to be a specific xenon effect, occurring even in subanesthetic concentrations of 30% and 50%.