Context: Acute lung injury (ALI) and ARDS are
currently defined by the American-European Consensus Conference
(AECC) definition criteria, which contain a radiographic criterion. The
accuracy or reliability of this consensus radiographic definition has
not been evaluated, and no radiographic definition of ALI-ARDS has been
evaluated by a large international group of experts.
Objective: To study the interobserver variability in
applying the AECC radiographic criterion for ALI-ARDS.
convenience sample of 21 experts selected from participants attending
the 1997 Toronto Mechanical Ventilation Workshop and from members of
the National Institutes of Health ARDS Network.
measures: Participants reviewed 28 randomly selected chest
radiograph from critically ill, hypoxemic
(Pao2/fraction of inspired oxygen ratio,< 300) patients and decided whether the radiograph fulfilled the AECC
definition for ALI-ARDS.
agreement in applying the AECC definition for ALI-ARDS was moderate
(κ = 0.55; 95% confidence interval, 0.52 to 0.57). Thirteen
radiographs (43%) showed nearly complete agreement (defined as 20 or
21 readers in agreement). Nine radiographs (32%) had more than or
equal to five dissenting readers. The percentage of radiographs
interpreted as consistent with ALI-ARDS by individual readers ranged
from 36 to 71%. Participants commented that mild infiltrates, pleural
effusions, atelectasis, isolated lower lobe involvement, radiographic
technique, and overlying monitoring equipment posed the most
Conclusions: The radiographic criterion
used in the current AECC definition for ALI-ARDS showed high
interobserver variability when applied by expert investigators in the
fields of mechanical ventilation and ARDS. This variability may result
in differences in ALI-ARDS populations at different clinical research
centers and may make it difficult for clinicians to apply the results
of clinical trials to their patients. Modifications to the radiographic
criterion or annotated reference radiograph may improve the reliability
of future definitions for ALI-ARDS.