Fig. 1

Patients’ flowchart. VAP ventilator-acquired pneumonia, CPIS Clinical Pulmonary Infection Score, AS aerosolised, IV intravenous, COS colistin-only susceptible. *The order of randomization was as follows: Block 1: AS, AS, IV, IV; Block 2: AS, IV, AS, IV; Block 3: IV, IV, AS, AS; Block 4: IV, AS, IV, AS. Details of combination are displayed in Table 1