Weaning failure from mechanical ventilation : a scoping review of the utility of ultrasonography in the weaning process

Abstract

Background: Weaning failure has been associated with increased hospital stay and higher mortality. Identification of the risk factors that may affect weaning outcome is paramount. Ultrasonography is an excellent tool for pulmonary and diaphragmatic monitoring during mechanical ventilation, allowing real-time evaluation of anatomical structures and function. We performed a scoping review to highlight the usefulness and limitations of ultrasonography as a tool for detecting weaning failure. Methods: The Joanna Briggs Institute recommendations, the PRISMA Extension for Scoping Reviews (PRISMA-ScR) checklist, and the methodological framework by Arksey and O'Malley were followed. We searched PubMed, Scopus, and Cochrane databases for observational and randomised studies published from inception to August 12, 2024. Inclusion criteria were articles written in English, intensive care unit setting, mechanical ventilation, adults, and those that described a measure for burden of weaning failure using ultrasonography. Results: The search revealed 3573 records. After removal of duplicates, 3117 articles were screened for potential inclusion, of which 89 articles were finally included. These comprised six clinical trials, 80 observational prospective studies, and three retrospective studies. In total, 6841 subjects were included, with a weaning failure rate of 28.2%. The parameters most associated with weaning failure were higher ratio of early diastolic mitral inflow velocity to early diastolic septal mitral annulus velocity, diaphragmatic excursion, diaphragm thickening fraction, diaphragmatic rapid shallow breathing index, ratio between ventilatory frequency, diaphragmatic displacement, excursions, and contraction velocity on coughing. Loss of aeration, pulmonary oedema, and pleural effusion detected with ultrasound were associated with weaning failure and airway obstruction caused by post-extubation laryngeal oedema. Conclusions: Ultrasound represents a valuable tool for optimising the weaning process. It enables precise assessment of lung function and diaphragmatic performance, underscoring the need for its implementation in ICU setting.