Haemodynamic effects of haemorrhage during xenon anaesthesia in pigs

Background. It was hypothesized that xenon would stabilize meanarterial pressure (MAP) in haemorrhagic shock, recovery, andvolume resuscitation, because a higher MAP has been observedwith xenon, when compared with isoflurane anaesthesia. The responsesto haemorrhage and subsequent volume replacement were thereforecompared between xenon and isoflurane anaesthesia, in pigs. Methods. Pigs were randomized to anaesthesia with xenon 0.55MAC (group Xe, n=9) or isoflurane 0.55 MAC (group Iso, n=9),each with remifentanil 0.5 µg kg^–1 min^–1.MAP, heart rate, cardiac output (CO), and left ventricular fractionalarea change (FAC) were collected at control (1), after haemorrhage(20 ml kg^–1) (2), after 10 min of recovery (3), aftervolume replacement (4), and 30 min later (5). Data were analysedby two-way repeated measures ANOVA. Results. Blood loss decreased MAP (Xe: 103 21] to 53 24] mmHg; Iso: 92 18] to 55 14] mm Hg) and CO (Xe: 4.1 0.8] to2.6 0.5] litre min^–1; Iso: 5.1 1.1] to 3.8 1.2] litremin^–1), in spite of significant tachycardia. MAP and COrecovered to about 75% of control, and subsequent volume replacementcompletely reversed symptoms in both groups, but increased FAConly with xenon. Conclusion. Haemodynamic response to acute haemorrhage appearedfaster with xenon/remifentanil than with isoflurane/remifentanilanaesthesia. In particular MAP decrease and short-term recoverywere more marked with xenon (P<0.02). In the xenon group,volume replacement increased FAC compared with control and isoflurane(P<0.02).