Transcranial Monitoring of Cerebral Oxygen Saturation under Different Anesthetic Drugs and Ventilation Patterns: Observations in an Animal Model

Background: Transcranial regional cerebral oxygen saturation (rSO2) is based on specific algorithms of near infrared spectroscopy (NIRS). In an animal model we measured the reactivity of rSO2 trends under basal total intravenous anesthesia (TIVA) with propofol and remifentanil during different experimental interventions. These maneuvers included the additional application of desflurane and halothane as well as hypoand hyperventilation in two pigs.Results: Induced hypercapnia during administration of desflurane and halothane led to increased rSO2 values. Administration of thiopental (5mg/kg bolus followed by 3mg/kg/h continuously) under normocapnia also led to increased rSO2 values. In contrast, thiopental administration during hypocapnia led to moderately decreased rSO2 readings.Conclusion: Monitoring of cerebral oxygenation metabolism seems to be a control tool in an interventional setting using the combination of thiopental and hyperventilation. Further studies in this context using NIRS monitoring and cerebral tissue oxygenation appear warranted.