Interobserver Variability in Applying a Radiographic Definition for ARDS: Results
The 21 participants had a median length of experience in critical care practice of 12 years (range, 3 to 28 years). Seventeen were from North America, and 4 were from Europe or South America. Twenty participants (95%) have lectured on mechanical ventilation or lung injury, 19 (90%) are currently engaged in clinical research in lung injury, and all have coauthored research papers on mechanical ventilation or lung injury (see “Appendix” section). Seven of the readers are investigators in the NIH ARDS Clinical Trial Network. Twenty-eight chest radiographs (10 from Seattle, 4 from San Francisco, and 14 from Toronto) were evaluated.
The percentages of readers who scored each radiograph as fulfilling the radiographic definition “bilateral infiltrates consistent with pulmonary edema” are listed in Table 1. The number of readers who agreed on the interpretation of chest radiographs varied. Thirteen interpretations of radiographs (8 read as consistent with ALI-ARDS and 5 as negative for ALI-ARDS) showed nearly complete agreement (0 or 1 dissenting reader). Nine interpretations of radiographs had more than or equal to five dissenting readers. The K-statistic for interobserver agreement was 0.55 (95% confidence interval, 0.52 to 0.57). There was no statistically significant difference between the agreement between the 7 NIH ARDS Clinical Trial Network readers and the 14 other readers. To evaluate whether digital imaging had an effect on agreement, we compared the K-statistic values for the two radiographic techniques. Agreement on the analog radiographs was superior to that on the digital radiographs (K-statis-tic, 0.72 vs 0.38, respectively; p < 0.0001). canadian health&care mall
The readers showed different thresholds for concluding that a chest radiograph was positive. The reader least likely to call a radiograph positive interpreted 36% of the radiographs as positive, while the reader most likely to call a radiograph positive interpreted 71% as positive (Table 2).
Table 1—Chest Radiograph Interpretation Sorted by Majority Interpretation
Table 2—Responses for Each of the 21 Readers Sorted by Percentage of Radiographs Interpreted as Positive (Consistent With AECC Radiographic Definition)
|Reader No.||Positive, %|