To the Editor
We read with interest the publication “Point-of-Care Lung Ultrasound to Evaluate Lung Isolation During One-Lung Ventilation in Children: A Blinded Observational Feasibility Study” by Moharir et al. We applaud the authors for this study, which is vastly relevant to pediatric thoracic anesthesia practice. However, we would like to highlight a few issues regarding the study design and methodology.
The study has evaluated the accuracy of 2 methods, lung ultrasound and auscultation, to confirm lung isolation in children. It is therefore a “diagnostic” study and not a “feasibility” study as described in the title. For the same reason, the Standards of Reporting of Diagnostic Accuracy guidelines would be more appropriate for this study rather than Consolidated Standards of Reporting Trials guidelines, which are used for randomized controlled trials.
There is a mention of randomization, but there is no description of why and how it was performed. Blinding of the sonologist and the auscultator to the side of one-lung ventilation was appropriate to avoid bias. However, it would have been better if the auscultator and sonologist were in addition blind to each other’s findings. According to the study protocol, the evaluation of lung isolation by ultrasound and auscultation was done in the supine position, while the confirmation was done in the lateral position during surgery. There is a high possibility of displacement of airway devices during positioning, especially in children, which could have affected the results. To circumvent this problem, the evaluation of lung isolation by ultrasound and auscultation would have been ideal. The enrolled patients varied widely in age, ranging from 0 to 20 years. The efficacy of ultrasound and auscultation for detection of lung isolation may vary in different ages. Therefore, further investigations are required in children of different age groups. Lastly, a major limitation of the study is that while a sample size of 41 was calculated, data of only 34 patients were analyzed, undermining the results.