The investigator's goal in this study is to evaluate the efficacy and safety of nebulized amikacin versus intravenous amikacin in patients with hospital and ventilator acquired pneumonia in surgical patients admitted to the intensive care units infected with gram negative bacilli

prospective, randomized, controlled study on post-cardiac surgery patients , included two groups, over one year period. The first group was administered intravenous (IV) amikacin 20 mg/kg once daily. The second group was prescribed amikacin nebulizer 400 mg twice daily. Both groups were co-administered intravenous (IV) piperacillin/tazobactam empirically.

Inclusion Criteria:

• Patients admitted to ICU
• Clinical suspicion of VAP or HAP defined by a new persistent radiological infiltrate and one of the following signs:
• purulent tracheal aspirations, or
• temperature of 38° or higher, or leucocyte count > 10000/ml or
• Positive culture sensitive to amikacin
• In case of empirical treatment, risk of multi resistant bacteria defined as follows:
• Antimicrobial therapy in preceding 90 days and
• Current hospitalization of 5 d or more

Exclusion Criteria:

• History of Asthma
• Multi organ failure or any psychiatric illness
• allergy to amikacin or intolerance to nebulized amikacin
• Myasthenia gravis.
• Severely impaired renal function (creatinine clearance lower than 10 mL/min or renal replacement therapy)
• Vestibulo-cochlear disease.
• Pregnancy.
• Brain death