normal saline 2 mL nebulized Q 8 hours placebo for gentamicin or vancomycin

vancomycin 120 mg every 8 hours or gentamicin 80 mg every 8 hours

Choice of antibiotic is determined by Gram stain of sputum.The antibiotic is administered via nebulization through the ventilator circuit every 8 hours

Tracheal aspirates are taken at randomization. Randomization to drug is determined by the Gram stain(organisms are Gram-positive, Gram-negative or both). End of treatment culture, susceptibility and Gram stain of tracheal aspirate is taken after 14 days of treatment or at time of extubation, (which ever comes first).

Eradication is defined as absence of growth in culture and absence of organisms on Gram stain.

CPIS is an index for risk of respiratory infection using a number of signs and symptoms . An index of greater than or equal to 6 suggests pneumonia