Complete bacterial filter blockage by a plastic film.

We describe a case where the expiratory bacterial filter was completely blocked by a plastic membrane. Significantly increased airway pressures and inability to deliver adequate tidal volume to the patient were experienced. The cause of machine failure could not be identified until a complete preanesthesia machine manual check was performed. All machines and circuits should be checked manually, even with the availability of new and advanced self-tests in machines. Backup ventilation equipments and familiarity with signs of expiratory and inspiratory limb obstruction should not be underestimated.