Xenon is not superior to isoflurane on cardiovascular function during experimental acute pulmonary hypertension.

Background: Acute right ventricular afterload increase is a known perioperative challenge for the anaesthetic regime especially for patients with a compromised right ventricle. The accused negative inotropic action of volatile anaesthetics, with the exception of xenon, might be crucial for the adaptation of the right ventricle.
Methods: Reversible pulmonary hypertension (mean pressure 40 mmHg) was induced by an infusion of the stable thromboxane A(2) analog U46619 in a porcine model (n = 35). The effects of 70 vol% xenon and 0.9 vol% isoflurane on biventricular function were studied by conductance catheter technique. Inflammation and myocardial injury was quantified using serum probes [tumour necrosis factor α (TNFα), interleukin 6 (IL-6), troponin] and myocardial tissue [B natriuretic peptide (BNP), TNFα, activated caspase 3] by enzyme-linked immunosorbance assays and reverse-transcription polymerase chain reaction.
Results: After wash in of xenon global haemodynamic parameters remained stable whereas isoflurane caused a systemic vasodilation. This led to a significant decrease in mean arterial pressure in the isoflurane group whereas cardiac output remained stable. Both substances did not alter the biventricular contractility nor did they induce changes in preload for both ventricles. Xenon led to an additional increase in right ventricular afterload, whereas isoflurane reduced pulmonary vascular resistance. No effects on systemic inflammatory response and myocardial injury were found, whereas higher apoptosis rate and expression of BNP and IL-6 was determined in the right ventricle.
Conclusions: These results do not support the idea that xenon is more beneficial than isoflurane in right ventricular failure during pulmonary hypertension. Isoflurane did not compromise systolic ventricular function during acute PHT it only led to vasodilation in contrast to xenon.
(© 2012 The Authors. Acta Anaesthesiologica Scandinavica © 2012 The Acta Anaesthesiologica Scandinavica Foundation.)