key: cord-0747873-yfpppegh authors: Avdeev, Sergey N.; Nekludova, Galina V.; Trushenko, Natalia V.; Tsareva, Natalia A.; Yaroshetskiy, Andrey I.; Kosanovic, Djuro title: Lung ultrasound can predict response to the prone position in awake non-intubated patients with COVID‑19 associated acute respiratory distress syndrome date: 2021-01-25 journal: Crit Care DOI: 10.1186/s13054-021-03472-1 sha: ef7fb084cde064e2bbcedd0fa59679ac6ac9e88a doc_id: 747873 cord_uid: yfpppegh nan To the Editor, Prone positioning (PP) is a well-known therapeutic strategy used in acute respiratory distress syndrome (ARDS). Several studies demonstrated positive effects of PP on oxygenation parameters in awake non-intubated patients with COVID-19-associated ARDS [1] [2] [3] . However, PP is not effective in every case. The pilot study by Elharrar et al. demonstrated a significant improvement of oxygenation parameters during PP in only 25% of the patients [3] . The results of previous studies highlighted heterogeneity of COVID-19-associated ARDS, which demands further studies of the predictors of PP effectiveness and indications for its use in COVID-19 patients. The main objective of our study was to evaluate whether the changes of lung aeration assessed by lung ultrasound (LUS) can predict the oxygenation response during PP. This prospective cohort study was conducted in COVID-19 care units of two university-affiliated hospitals (Sechenov University) between April 8 and May 10, 2020. The study included spontaneously breathing patients with confirmed or suspected diagnosis of COVID-19, and bilateral changes detected by high-resolution computed tomography and PaO 2 /FiO 2 < 300 mmHg. Sixteen of 22 patients (72.7%) responded to PP treatment with significant increase in PaO 2 /FiO 2 . At the same time, fewer patients had clinically significant improvement in dyspnea score-3 patients (13.6%) at 15 min in PP and 12 patients (54.5%) at 3 h in PP (Table 1) . RR also significantly improved in responders. Responders and non-responders demonstrated significant differences in disease duration (8.5 (5.0-10.8) vs. 13.0 (10.0-17.0) days of disease, p = 0.02), no other differences in baseline clinical and laboratory parameters were observed. Three patients (all from non-responder group) were transferred to intensive care unit and then intubated, two of them died. The patients who responded to PP had more pronounced disturbances of aeration in posterior regions PP was 0.87 (95% CI 0.64-1.0; p < 0.01). Changes of aeration score over time in posterior segments by LUS data correlated with PaO 2 /FiO 2 changes (r = 0.53, p = 0.01), i.e. aeration improvement in posterior lung segments was associated with improved oxygenation status (Fig. 1) . Previous studies examined the changes of aeration by LUS in PP in intubated patients with ARDS not-associated with COVID-19 [5, 6] . Haddam et al. found that oxygenation response to PP was not correlated with a specific LUS pattern regardless of the focal or non-focal nature of ARDS [5] . However, Wang et al. demonstrated that aeration score changes assessed by LUS were significantly higher in the PP responder and survivor groups [6] . Our study demonstrated in awake non-intubated patients with COVID-19-associated ARDS the relationship between the pattern of lung changes (presence of areas with subpleural consolidations), their localization The study protocol included the measurement of SpO 2 , respiratory rate (RR), heart rate (HR) and dyspnea assessment using Borg-Dyspnea-Scale (at baseline, after 15 min in PP, after 3 h in PP, 15 min and 1 h after turning in supine position). Arterial blood gas analysis was measured twice: at baseline and after 3 h in PP. The increase of PaO 2 /FiO 2 by 20 mmHg in 3 h after turning a patient into the prone position was used as the criterion of the response to PP. All parameters of respiratory support and FiO 2 were the same during supine and prone positions. Before PP and after 3 h in PP semi-quantitative assessment of the lung tissue was performed by LUS. The study protocol included 14 areas for scanning (two anterior, two lateral and three posterior regions of each hemithorax) [4] Data are expressed as median (inter-quartile range). PaO 2 /FiO 2 (mmHg): arterial oxygen tension to inspired oxygen fraction ratio; PaCO 2 (mmHg): arterial carbon dioxide tension; SpO 2 /FiO 2 : arterial oxygen saturation to inspired oxygen fraction ratio; RR (min In conclusion, in patients with severe COVID-19, response to PP probably depends on the extent and localization of lung tissue changes. The aeration changes assessed by LUS may be useful in prediction of oxygenation response to PP in awake non-intubated patients with COVID-19-associated ARDS. Feasibility and physiologic effects of prone positioning in non-intubated patients with acute respiratory failure due to COVID-19 (PRON-COVID): a prospective cohort study Respiratory parameters in patients with COVID-19 after using noninvasive ventilation in the prone position outside the intensive care unit Use of prone positioning in nonintubated patients with COVID-19 and hypoxemic acute respiratory failure Proposal for international standardization of the use of lung ultrasound for patients with COVID-19 patients: a simple, quantitative, reproducible method Lung ultrasonography for assessment of oxygenation response to prone position ventilation in ARDS Lung ultrasound can be used to predict the potential of prone positioning and assess prognosis in patients with acute respiratory distress syndrome Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations None. Concept and design of the study, and drafting of the manuscript: SNA; supervision and drafting of the manuscript: DK; performing the measurements and collection of data: GVN NVT NAT AIY. Transthoracic LUS was performed by two expert physicians (GVN, AIY) with expertise in LUS recording and interpretation. Double reading was conducted to reduce inter-and intra-observer variability and final decisions were reached by consensus. Our physicians were blinded to the individual patients´ oxygenation response. All authors were involved in data analysis and interpretation. Finally, all authors were involved in writing, reviewing and editing of the manuscript. All authors read and approved the final manuscript. None. Data and materials can be obtained from the corresponding author upon the reasonable request. The local ethics committee (LEC No. 16-2016-20) approved the study. The ethics committee of the hospitals (Sechenov First Moscow State Medical University) waived the written informed consent from patients with COVID-19, and all the procedures being performed were part of the routine care. Not applicable. The authors declare that they have no competing interests.