Fig. 1. Diagram showing the experimental setting. The ultrasonic nebulizer is positioned 40 cm before the Y piece connecting inspiratory and expiratory limbs to the proximal tip of the endotracheal tube. An expiratory filter is inserted on the expiratory limb, just after the Y piece. Extrapulmonary deposition is defined as the amount of ceftazidime trapped in A , B , C , and D after nebulization.