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Table 1 Characteristics and methodological quality of randomized and quasi-randomized controlled trials of restrictive versus routine CXR strategies.

From: Routine chest x-rays in intensive care units: a systematic review and meta-analysis

Study ICU Population Patient selection criteria Location Total patients (n) CXRs/patients, restrictive group (n/n) CXRs/patients, routine group (n/n) Outcomes used in meta-analysis Method of allocation Allocation concealment Blinded outcomes assessmenta Zero losses to follow up
Krivopal et al., 2003 [16] Medical, Adult Ventilated for 48 to 72 hours
Exclusion criteria: reintubated, transferred from other centers
USA 94 226/51 293/43 ICU and hospital mortality
ICU and hospital length of stay
Duration of mechanical ventilation
Quasi-randomization based on last digit of medical record number No Not specified Yes
Clec'h et al., 2007b [15] Medical-surgical, Adult Ventilated for ≥ 48 hours
Exclusion criteria: reintubated, tracheostomy, or withdrawal of life support
France 165 94/81 885/84 ICU and hospital mortality
ICU and hospital length of stay
Computer-generated random number table Not reported Not specified Yes
Hejblum et al., 2009 [13] Medical-surgical, Adult Ventilated for ≥ 2 days France 611, 849c 3,148/306, 425c 4,607/305, 424c ICU mortality
ICU length of stay
Duration of mechanical ventilation
Computer-generated Not reported ('open-label with respect to allocation concealment') Not specified Yes
  1. aRadiologists and clinicians were not blinded to the group when interpreting films; bIn this trial all patients had daily CXRs, but results in the restrictive group were concealed from clinicians, who were free to order CXRs as needed. cThe first sample size is adjusted for the design effect due to clustering [14], assuming intracluster correlation 0.01 (design effect 1.39); the second is the unadjusted sample size as reported in the study. CXR, chest X-ray; n, number.