Comparison of routine and on-demand prescription of chest radiographs in mechanically ventilated adults: a multicentre, cluster-randomised, two-period crossover study

Background Present guidelines recommend routine daily chest radiographs for mechanically ventilated patients in intensive care units. However, some units use an on-demand strategy, in which chest radiographs are done only if warranted by the patient's clinical status. By comparison between routine and on-demand strategies, we aimed to establish which strategy was more efficient and effective for optimum patient care. Methods In a cluster-randomised, open-label crossover study, we randomly assigned 21 intensive care units at 18 hospitals in France to use a routine or an on-demand strategy for prescription of chest radiographs during the first of two treatment periods. Units used the alternative strategy in the second period. Each treatment period lasted for the time taken for enrolment and study of 20 consecutive patients per intensive care unit; patients were monitored until discharge from the unit or for up to 30 days' mechanical ventilation, whichever was first. Units enrolled 967 patients, but 118 were excluded because they had been receiving mechanical ventilation for less than 2 days. The primary outcome measure was the mean number of chest radiographs per patient-day of mechanical ventilation. Analysis was by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00893672. Findings 11 intensive care units were randomly allocated to use a routine strategy to order chest radiographs in the first treatment period, and 10 units to use an on-demand strategy. Overall, 424 patients had 4607 routine chest radiographs (mean per patient-day of mechanical ventilation 1.09, 95% CI 1.05-1.14), and 425 had 3148 on-demand chest radiographs (mean 0.75, 0.67-0.83), which corresponded to a reduction of 32% (95% CI 25-38) with the on-demand strategy (p<0.0001). Interpretation Our results strongly support adoption of an on-demand strategy in preference to a routine strategy to decrease use of chest radiographs in mechanically ventilated patients without a reduction in patients' quality of care or safety.