OBJECTIVE:This study aimed to determine the impact of providing chest physiotherapy after routine clinical assessment on the duration of mechanical ventilation, outcome and intensive care length of stay. DESIGN AND SETTING:Single-centre, single-blind, prospective, randomised, controlled trial in a university hospital general intensive care unit. PATIENTS AND PARTICIPANTS:180 patients requiring mechanical ventilation for more than 48 h. INTERVENTIONS:Patients randomly allocated, one group receiving physiotherapy as deemed appropriate by physiotherapists after routine daily assessments and another group acting as controls were limited to receiving decubitus care and tracheal suctioning. MEASUREMENTS AND RESULTS:Primary endpoints were initial time to become ventilator-free, secondary endpoints included intensive care unit (ICU) and hospital mortality and ICU length of stay. Kaplan-Meier analysis censored for death revealed a significant prolongation of median time to become ventilator-free among patients receiving physiotherapy (p=0.047). The time taken for 50% of patients (median time) to become ventilator-free was 15 and 11 days, respectively, for physiotherapy and control groups. There were no differences between groups in ICU or hospital mortality rates, or length of ICU stay. The number of patients needing re-ventilation for respiratory reasons was similar in both groups.