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 Jugular bulb and arterial blood samples for gas analysis were withdrawn during the administration of oxygen 33% with nitrogen 67% and then with N2O 67%.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 Sjo2 from 56% ± 13% to 66% ± 12% (P < 0.01). This indicates that N2O does not reduce the incidence of low Sjo2 values during propofol anesthesia.