Outcomes/PredictorsCan lung ultrasonography predict prone positioning response in acute respiratory distress syndrome patients?
Introduction
Once low stretch ventilation strategy is applied [1], prone positioning (PP) is an additional therapy for managing patients with severe acute respiratory distress syndrome (ARDS). Prone positioning has shown its routine feasibility [2], [3], [4] and potential oxygenation benefits, but may also induce various adverse events [5]. Up to 70% to 80% of ARDS patients experience oxygenation improvement with PP, but there are no conclusive criteria to predict oxygenation response [3].
General ultrasonography (US) is noninvasive, radiation-free, cheap, easy to use, and widely available as a bedside technique. Its use has increased in intensive care unit (ICUs) during the last decade. Ultrasonography has been validated for hemodynamic management, pleural effusions, and pneumothorax detection and central vein catheter placement [6], [7], [8], [9]. Moreover, superficial lung aspect can be visualized using lung ultrasonography (L-US).
The main objective of this preliminary prospective physiological study was to determine whether L-US patterns of aeration in specific pulmonary regions may predict PP oxygenation response in ARDS patients. We assumed that PP would be beneficial to patients with low aerated posterobasal regions and aerated anterior regions as identified using L-US.
Section snippets
Methods
Local ethics committees waived patients’ written informed consent (CHU Brest Ethics Committee and Comité de Protection des Personnes Ouest VI; 12/05/2011) given the noninvasive procedure used in this prospective physiological study.
Patients
Nineteen patients were prospectively included during a 13-month period: 12 were classified as severe and 7 as moderate ARDS patients according to the Berlin definition [10]. Initial physiological characteristics’ (H0) distribution according to oxygenation course at H2 and H14 is depicted in Table 1, Table 2. Eighteen patients remained within the same group (responders/nonresponders) between H2 and H14: 1 patient was classified as nonresponder at H2 and became responder at H14.
Most of the ARDS
Discussion
Prone positioning and the mechanism by which it can improve patient oxygenation have been investigated over the past years. Gattinoni et al described PP mechanism through a so-called sponge model. According to this model, patient’s oxygenation can be improved through inversion of gravitational forces with homogenous distribution of inflation throughout lung parenchyma. The latter depends on factors such as lung-chest wall shape matching and heart weight [20], [21]. According to Sud et al [22],
Conclusion
Despite several limitations due to the small sample of patients, this study highlighted the usefulness of easy-to-use bedside L-US in assessment of PP oxygenation response in ARDS patients. A normal L-US pattern of both left and right anterobasal regions in supine position may be useful in prediction of an early and late oxygenation improvement in PP.
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2023, Journal of Critical CareCitation Excerpt :Differences in correlation coefficients across anatomical regions hint that response is correlated not only to extent but also to localization. These findings are consistent with a previous ARDS study which suggested that a well-aerated anterior lung has greater potential for ventilation-perfusion matching [6]. Interestingly, another investigation suggests that a well-aerated anterior lung simply indicates a focal ARDS phenotype (prone sensitive) as opposed to non-focal ARDS (PEEP sensitive) [19].
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2020, ChestCitation Excerpt :Chest CT imaging also retains a significant role but can usually be reserved for situations in which LUS fails to answer the question at hand. LUS has added advantages as a dynamic imaging modality that can be repeated frequently to assess the effect of therapeutic interventions; using serial LUS examinations during weaning from mechanical ventilation, lung recruitment maneuvers, positive end expiratory pressure titration, or identification of the patient who may respond to prone positioning are common examples.13,22-28 Limitations associated with LUS relate primarily to operator factors (as an operator-dependent skill where training and experience are important) and patient factors (where elements such as obesity and immobility can make performing examinations difficult).
Lung Ultrasound May Support Diagnosis and Monitoring of COVID-19 Pneumonia
2020, Ultrasound in Medicine and BiologyCitation Excerpt :An increase in score and/or the presence of posterolateral/inferior consolidations indicate a decrease in aeration, suggesting the need for additional PEEP and recruitment maneuvers, while a decrease in score indicates re-aeration, suggesting the success of interventions and, eventually, weaning from respiratory support (Conway et al. 2020). To confirm this, although data on COVID-19 patients are still lacking, PEEP-induced lung recruitment (Lichtenstein et al. 2004; Bouhemad et al. 2011) and the response to prone positioning (Prat et al. 2016; Wang et al. 2016) can be adequately estimated with bedside LUS in patients with ARDS. LUS can be useful in confirming endotracheal tube placement (Das et al. 2015; Karacabey et al. 2016), which is particularly tricky in the COVID-19 area setting and when an end-tidal CO2 device is not available, and in detecting pneumothorax (Alrajab et al. 2013), which is frequently identified by an anterior extension in the critically ill patient in a recumbent or semirecumbent position.