Comparison of plasma propofol concentration for apnea, response to mechanical ventilation, and airway device between endotracheal tube and supraglottic airway device in beagles

The relationships between propofol plasma concentrations and the pharmacodynamic endpoints may differ according to a type of airway device. To clarify these relationships in different airway devices would be useful to avoid the complication such as apnea and intraoperative awareness. The aim of this study was to investigate the influence of difference of airway device on propofol requirement during maintenance of anesthesia in dogs. We compared the influence of airway devices on the plasma propofol concentrations for apnea, response to mechanical ventilation, and response to airway device between endotracheal tube (ETT) and supraglottic airway device (SGAD) in Beagles. The pharmacodynamic effects were repeatedly assessed at varying propofol concentrations. The plasma concentrations (mean ± SD) of propofol in the ETT and SGAD groups were 10.2 ± 1.8 and 10.9 ± 2.4 µg/ml for apnea (P=0.438), 7.9 ± 1.2 and 7.4 ± 1.5 µg/ml for response to mechanical ventilation (P=0.268), and 5.2 ± 0.7 and 5.4 ± 1.5 µg/ml for response to airway device (P=0.580), respectively. Required propofol concentration during maintenance of anesthesia may be similar between ETT and SGAD. Without moderate to strong stimuli such as airway device insertion or painful stimulation during surgery, the type of airway device may have little impact on required propofol concentration during maintenance of anesthesia in dogs.