Association Between Diaphragmatic Dysfunction and Weaning from Mechanical Ventilation in Critically Ill Patients: An Integrative Review

Abstract

Introduction: Invasive mechanical ventilation is an essential resource for the management of critically ill patients; however, its use may be accompanied by structural and functional changes in the respiratory muscles, particularly the diaphragm. Diaphragmatic dysfunction may be associated with difficulties during the ventilator weaning process, making its assessment relevant to the monitoring of recovery of spontaneous breathing. In this context, diaphragmatic ultrasonography and physiotherapeutic strategies targeting the respiratory muscles, such as inspiratory muscle training, have been investigated as assessment and intervention approaches during mechanical ventilation. Objective: To analyze the association between diaphragmatic dysfunction and weaning from mechanical ventilation in critically ill patients, considering its relationship to the success or failure of weaning, methods for assessing diaphragmatic function, and physical therapy strategies targeting the respiratory muscles. Methods: This is an integrative literature review, descriptive and analytical in nature, conducted in accordance with the methodological framework proposed by Whittemore and Knafl. Searches were conducted between August and September 2026 in the following databases: Virtual Health Library (VHL), Latin American and Caribbean Health Sciences Literature (LILACS), National Library of Medicine (PubMed/MEDLINE), Scopus, and Scientific Electronic Library Online (SciELO). Eligibility criteria were established to include primary, experimental, or observational studies published between 2011 and 2025 in Portuguese, English, or Spanish, involving critically ill adult patients on invasive mechanical ventilation and assessing diaphragmatic function, weaning from mechanical ventilation, and/or physical therapy strategies targeting the respiratory muscles. The selection process involved independent stages conducted by two reviewers, with a third reviewer to resolve disagreements, and the process was reported in accordance with the PRISMA guidelines. The synthesis was narrative and comparative, with separate analysis of observational and intervention studies, without the use of formal quality scores. Reviews and other secondary studies were excluded. Results: A total of 12 primary studies were included—four randomized clinical trials and eight observational studies—selected from 176 identified records, of which 31 duplicates were removed. After screening 145 titles and abstracts, 41 articles were evaluated in full, and 29 were excluded. The analyzed studies identified relationships between parameters of diaphragmatic function and various outcomes related to weaning from mechanical ventilation, including performance on the spontaneous breathing test, duration of mechanical ventilation, and occurrence of weaning failure. Diaphragmatic ultrasound was the primary assessment method investigated, with analysis of parameters such as excursion, thickness, and thickening fraction. However, its ability to predict extubation failure on its own was not consistent across the studies. Inspiratory muscle training showed favorable results regarding respiratory muscle strength parameters and, in certain contexts, was associated with a reduction in the duration of mechanical ventilation. However, it did not produce consistent effects on the duration of weaning, nor did it result in differences among the compared training protocols. Conclusion: Diaphragmatic dysfunction is related to different aspects of ventilator weaning in critically ill patients and may provide complementary information for assessing the ability to resume spontaneous breathing. Ultrasonographic assessment and inspiratory muscle training are strategies investigated in this context, but their findings should be interpreted together with the patient's clinical and respiratory conditions. The heterogeneity of assessment methods and outcomes reinforces the need for future studies with greater standardization of assessment and intervention protocols.