Purpose: The goal of this investigation was to examine the influence of two oxygenators with different membranes, made of either polypropylene (PPL) or polymethylpentane (PMP), on the plasma concentration of sevoflurane during cardiopulmonary bypass.
Methods: The concentrations of sevoflurane during cardiopulmonary bypass were examined in patient plasma, endotracheal tubes, cardiotomy reservoirs and the outlets of the heart-lung oxygenators in twenty patients who underwent elective heart surgery.
Results: The sevoflurane losses are smaller in cardiopulmonary bypass when using a polymethylpentane versus a polypropylene oxygenator. Ten minutes after beginning cardiopulmonary bypass, the sevoflurane plasma concentration in the PPL oxygenator group compared to the PMP oxygenator group fell significantly (PPL 0.48-1.79 (0.93) vs. PMP 0.80-2.15 (1.56) µL × 100 mL-1, p = 0.02). This difference persisted until ten minutes after the termination of cardiopulmonary bypass.
Conclusion: The results of this study show that using a polymethylpentane membrane oxygenator rather than a polypropylene oxygenator significantly reduces the losses of sevoflurane, resulting in higher plasma concentrations and greater depth of anesthesia.