RESULTS: There were 11,994 patient days from 1,947 ICU admissions of 1,729 patients (166 patients had more than one admission). Intervention cohort characteristics (combined) were: Age: 56.7(SD: 17.6), 66% male, 96% survival, APACHE II 14 (IQR: 11-19), MV (occurrences) / patient admission: mean 0.7 (SD: 0.6; range: 0-5), duration (hours) of MV: 21.7 (IQR: 9.8-81.4) and ICU LOS (days): 2.8 (IQR: 1.8-5.6). The average pCXR rate per patient per day before the intervention was 0.93 (95% CI: 0.89~0.96), and after the intervention it was 0.73 (95% CI: 0.69~0.77). After controlling for patient severity characteristics, daily pCXR rate immediately following the intervention decreased by 21.7% (p<0.001). The daily CXR rate following the intervention steadily increased over 10.8 months by about 3% / month (p=0.044) without further intervention. There was no change in APACHE II, mortality, and occurrences of MV, unplanned re-intubations, ICU LOS, or duration of MV.