Therapy
Are daily routine chest radiographs useful in critically ill, mechanically ventilated patients? A randomized study.
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Summary
Posted By: Gordon Doig
E-Mail: gdoig@med.usyd.edu.au
Posted Date: 1 Feb 2008
Title: Are daily routine chest radiographs useful in critically ill, mechanically ventilated patients? A randomized study.
Authors: Clec'h C, Simon P, Hamdi A, Hamza L, Karoubi P, Fosse JP, Gonzalez F, Vincent F, Cohen Y.
Reference: Intensive Care Med. 2007 Nov 10 [Epub ahead of print]
Link: Click here for a direct link to the paper. A password may be required for access to fulltext.
Abstract: OBJECTIVE: Whether chest radiographs (CXRs) in mechanically ventilated patients should be routinely obtained or only when an abnormality is anticipated remains debated. We aimed to compare the diagnostic, therapeutic and outcome efficacy of a restrictive prescription of CXRs with that of a routine prescription, focusing on delayed diagnoses and treatments potentially related to the restrictive prescription.
DESIGN: Randomized controlled trial.
SETTING: Intensive care unit of the Avicenne Teaching Hospital, Bobigny, France.
PATIENTS AND PARTICIPANTS: All consecutive patients mechanically ventilated for[Symbol: see text]>/=[Symbol: see text]48[Symbol: see text]h between January and June 2006.
INTERVENTIONS: Patients were randomly assigned to have daily routine CXRs (routine prescription group) or clinically indicated CXRs (restrictive prescription group).
MEASUREMENTS AND RESULTS: For each CXR, a questionnaire was completed addressing the reason for the CXR, the new findings, and any subsequent therapeutic intervention. The endpoints were the rates of new findings, the rates of new findings that prompted therapeutic intervention, the rate of delayed diagnoses, and mortality. Eighty-four patients were included in the routine prescription group and 81 in the restrictive prescription group. The rates of new findings and the rates of new findings that prompted therapeutic intervention in the restrictive prescription group and in the routine prescription group were 66% vs. 7.2% (p[Symbol: see text]<[Symbol: see text]0.0001), and 56.4% vs. 5.5% (p[Symbol: see text]<[Symbol: see text]0.0001) respectively. The rate of delayed diagnoses in the restrictive prescription group was 0.7%. Mortality was similar.
CONCLUSIONS: Restrictive use of CXRs in mechanically ventilated patients was associated with better diagnostic and therapeutic efficacies without impairing outcome.
 
Are the Results Valid?
1. Was the assignment of patients to treatments randomized? ( Was allocation concealment maintained?)
Unsure. Although the authors do provide information about how the randomization sequence was generated, we are not told how allocation concealment was maintained. The authors should have told us whether they used sequentially numbered, opaque sealed envelopes (SNOSE), central phone randomisation, concealed web site or pharmacy based concealment.
2. Were all patients who entered the trial properly accounted for and attributed at its conclusion?
2a. Was followup complete?
Yes. 165 patients were randomized and outcomes were reported for all 165.
2b. Were patients analyzed in the groups to which they were randomized?
Yes. All patients were analyzed in the group to which they were originally randomised to.
3. Were patients, health workers, and study personnel blind to treatment?
No. Unfortunately the people conducting the study were also reading the x-rays AND determining what treatment was/was not required based on x-ray findings. It would not have been too much work to have the x-ray findings / treatment recommendations ascertained by readers blinded to the group to which patients were randomized to.
4. Were the groups similar at the start of the trial?
Table 1 demonstrates acceptable baseline balance. The apparent imbalance in COPD is likely a misprint (the reported %'s add up, but the numbers do not. Based on %'s, there is no imbalance).
5. Aside from the experimental intervention, were the groups treated equally?
Uncertain. We do not know the onset of ARDS after randomization, differences in ventilation modes etc.
What are the Results?
1. How large was the treatment effect?
Except when complex statistical techniques are used, such as in a cluster randomized trial, the unit of randomization (patients) should always serve as the denominator in any analysis. I have recalculated the primary findings using the number of patients as denominator. This is not ideal, but it is more conservative:
New findings:
62/81 restrictive vs 64/84 routine, p=0.897
Missed findings in restrictive group:
6 out of 81 patients = 7% (95% CI 3% to 15%)
Missed therapeutic interventions as a result of missed findings in restrictive group:
0 interventions out of 81 patients = 0% (95% CI 0% to 4.45%)
2. How precise was the estimate of the treatment effect?
See above for 95% CIs
Will the Results Help Me In Caring For My Patients?
1. Can the results be applied to my patient care?
Yes, most ICU's perform routine chest x-rays. This paper provides an estimate of the treatment opportunities that may be missed by not doing routine chest x-rays.
2. Were all clinically important outcomes considered?
No. The sample size may have been too small to capture a good estimate of missed viewings of tube misplacements and the clinical consequences thereof.
It would be interesting to see a true economic analysis that captures up-front costs and costs of consequences.
3. Are the likely treatment benefits worth the potential harms and costs?
Uncertain.

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Are daily routine chest radiographs useful in critically ill, mechanically ventilated patients? A randomized study.

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