Comparative Study between Lung Ultrasound as Diagnostic Modality of Lung Aeration versus Computed Tomography in Invasively Ventilated Patient

Abstract Background Ventilator-associated pneumonia (VAP) is one of the most frequent ICU- acquired infections. Reported incidences vary widely from 5 to 40% depending on the setting and diagnostic criteria. Ventilator-associated pneumonia is associated with prolonged duration of mechanical ventilation and ICU stay. Aim of the Work to evaluate the efficacy of lung ultrasound in diagnosis and follow up of ventilator associated pneumonia in comparison to lung CT and to assess the concordance between lung ultrasound scores and CT aeration scores as assessment tools for lung aeration in different lung regions. Patients and Methods To achieve this aim, this study was conducted on 40 Ventilator- associated pneumonia patients who were assessed by lung ultrasound and CT at different time points. The chest CT is ordered by the treating physician as part of clinical care. Then, patients undergo a comprehensive LUS exam in the last minutes before transport to the CT scanner while already connected to the transport ventilator. As part of follow up for each patient LUS will be done at day 0, 3 and 6, while CT at day 0 and 6 of the study (1st LUS and CT). Results Mean age of the included patients was 57.7 ± 11.2 years with male predominance (65%). Mean APACHE II score was 20.8 ± 6.39 and mean APACHE II percent was 38.1 ± 15.9. Baseline lung ultrasound reported similar findings to the CT with higher affection of aeration in lower anterior, lower middle, upper posterior (B2 pattern; poor aeration) and lower posterior areas (C pattern) in both lungs. The lung ultrasound score had comparable ability to detect the changes over time and reported similar changes in the same lung areas where significant percent of patients changed from B2 pattern to B1 or A pattern or changed from C pattern to B or A pattern. Overall, at any time points, concordance between the lung ultrasound findings and CT findings was shown as regard lung aeration at different regions in both sides. As regard the association between B- line count score and lung aeration by CT aeration by HU, poor correlations were present, and it was limited to upper anterior lung areas only. Transfer- related complications were reported in 62.5% of patients at day 0 and 27.5% of patients at day 6 with overall incidence (45%). The rate decreased significantly from day 0 to day 6 due to the reported significant improvement in lung condition and presence of patients who were no intubated at day 6. The commonest reported adverse events were hypoxia and hypotension. Conclusion lung ultrasound score and B- line percentage score had the ability to detect ventilator associated pneumonia with similar efficacy to lung CT. Also, lung ultrasound is considered a good assessment tool to be used for following up of such patients with good reliability and reproducibility.