Does monitoring end-tidal isoflurane concentration improve titration during general anesthesia?
STUDY OBJECTIVE: To assess the value of end-tidal anesthetic gas monitoring with respect to intraoperative hemodynamic stability and recovery times. DESIGN: Randomized blinded study. SETTING: Operating rooms at a university teaching hospital. PATIENTS: 120 ASA I and II patients receiving general anesthesia maintained with isoflurane and nitrous oxide (N2O). INTERVENTIONS: Following a standardized induction technique, patients were assigned to either an end-tidal isoflurane monitored (n = 60) or unmonitored (n = 60) group. During each operation, the anesthesiologist attempted to maintain an adequate “depth of anesthesia” by varying the administered concentration of isoflurane with or without information from an end-tidal isoflurane monitor. Intraoperative hemodynamic stability was assessed by determining the variation from a preincisional “baseline” mean arterial pressure (MAP) value established during a 10 minute interval immediately prior to the surgical incision. Recovery times were
