The effect of nitrous oxide on jugular bulb oxygen saturation during remifentanil plus target-controlled infusion propofol or sevoflurane in patients with brain tumors

Abstract

During propofol/fentanyl anesthesia, a large percentage of patients have jugular bulb oxygen saturation (Sjo2) <50%. The incidence is less with isoflurane/N2O. We evaluated the effect of N2O on Sjo2 during remifentanil-based anesthesia with concurrent propofol or sevoflurane in 20 adults undergoing brain tumor surgery. Anesthesia was randomized: Group 1 (n = 10), target-controlled infusion propofol; and Group 2 (n = 10), thiopental 2-3 mg/kg followed by sevoflurane 0.9% end-tidal. Jugular bulb and arterial blood samples for gas analysis were withdrawn during the administration of oxygen 33% with nitrogen 67% and then with N2O 67%. All samples were drawn before surgery and 20 min after the addition of the study gas and with an ETco2 26-28 mm Hg and mean arterial pressure >90 mm Hg. Both groups had similar demographic and physiologic data. In the Propofol group, Sjo2 was 50% ± 10% with nitrogen and 52% ± 9% with N2O (not significant); in the Sevoflurane group, however, N2O 67% increased