Fig. 2. Lung tissue concentrations of ceftazidime obtained in 15 piglets with noninfected lungs. Fifteen minutes after intravenous administration of 33 mg/kg ceftazidime (n = 5) or administration of 1 g ceftazidime by an ultrasonic nebulizer, using 65%/35% nitrogen–oxygen (n = 5) or helium–oxygen (n = 5) as the operating gas of the ventilator, animals were killed, and five juxtapleural specimens were collected from the upper, middle, and lower lobes to obtain representative distal lung tissue samples. Tissue concentrations are expressed in μg/g. Nebulization dramatically increased ceftazidime lung deposition, and there was an additional 33% increase in lung tissue concentrations when using the helium–oxygen rather than the nitrogen–oxygen mixture (* P < 0.001). He = helium; O2= oxygen.