Diaphragm ultrasound to predict weaning outcome: systematic review and meta-analysis

Predictors of weaning failure in ventilated intensive care patients: a systematic evidence map

BACKGROUND

Ventilator weaning is of great importance for intensive care patients in order to avoid complications caused by prolonged ventilation. However, not all patients succeed in weaning immediately. Their spontaneous breathing may be insufficient, resulting in extubation failure and the subsequent need for reintubation. To identify patients at high risk for weaning failure, a variety of potential predictors has already been examined in individual studies and meta-analyses over the last decades. However, an overview of all the predictors investigated is missing.

AIM

To provide an overview of empirically investigated predictors for weaning failure.

METHODS

A systematic evidence map was developed. To this end, we conducted a systematic search in the Medline, Cochrane, and CINAHL databases in December 2023 and added a citation search and a manual search in June 2024. Studies on predictors for weaning failure in adults ventilated in the intensive care unit were included. Studies on children, outpatients, non-invasive ventilation, or explanatory factors of weaning failure were excluded. Two reviewers performed the screening and data extraction independently. Data synthesis followed an inductive approach in which the predictors were thematically analyzed, sorted, and clustered.

RESULTS

Of the 1388 records obtained, 140 studies were included in the analysis. The 112 prospective and 28 retrospective studies investigated a total of 145 predictors. These were assigned to the four central clusters 'Imaging procedures' (n = 22), 'Physiological parameters' (n = 61), 'Scores and indices' (n = 53), and 'Machine learning models' (n = 9). The most frequently investigated predictors are the rapid shallow breathing index, the diaphragm thickening fraction, the respiratory rate, the P/F ratio, and the diaphragm excursion.

CONCLUSION

Predictors for weaning failure are widely researched. To date, 145 predictors have been investigated with varying intensity in 140 studies that are in line with the current weaning definition. It is no longer just individual predictors that are investigated, but more comprehensive assessments, indices and machine learning models in the last decade. Future research should be conducted in line with international weaning definitions and further investigate poorly researched predictors. Registration, Protocol: https://doi.org/10.17605/OSF.IO/2KDYU.

Diagnostic accuracy of lung ultrasound to predict weaning outcome: a systematic review and meta-analysis

Background

This systematic review and meta-analysis aim to systematically assess the diagnostic accuracy of lung ultrasound in predicting weaning failure from mechanical ventilation in critically ill patients.

Methods

We searched the relevant literature up to January 2024 in the databases Web of Science, Cochrane Library, Embase, and PubMed. Two researchers independently screened eligible studies and extracted data; disagreements, if any, were resolved through discussion or consultation with a third-party expert. The quality of the included studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. Statistical analyses were performed using Review Manager version 5.3 and Stata version 18.0, applying bivariate random-effects models to estimate sensitivity, specificity, diagnostic odds ratios, and their 95% confidence intervals, as well as to summarize receiver operating characteristic curves. Inter-study heterogeneity was assessed using the I-squared statistic, and potential sources of heterogeneity were explored by meta-regression analysis. The study follows the guidelines for Preferred Reporting Items for Systematic Reviews and Meta-Analyses in reporting.

Results

Fourteen studies were included in the systematic review, of which 13 studies (totaling 988 patients) were included in the meta-analysis. The meta-analysis revealed an overall sensitivity of 0.86 (95% confidence interval: 0.77-0.91) and a specificity of 0.75 (95% confidence interval: 0.66-0.83) for lung ultrasound in predicting extubation failure. The area under the receiver operating characteristic curve was 0.87 (95% confidence interval: 0.84-0.89). Meta-regression analysis identified lung ultrasound thresholds, reference standards (extubation outcomes), and study flow and time bias as significant factors influencing diagnostic accuracy.

Conclusion

This systematic review and meta-analysis demonstrated that lung ultrasound has high diagnostic accuracy in predicting extubation failure in mechanically ventilated critically ill patients. Despite some study heterogeneity, lung ultrasound proved to be a reliable predictive tool for extubation failure. Future research should focus on standardizing the definition of extubation failure, exploring the impact of different thresholds on the predictive ability of lung ultrasound, and validating its application in various clinical settings to enhance its utility and accuracy in clinical practice.

Systematic review registration

This systematic review and meta-analysis was registered with PROSPERO (registration number: CRD42024555909). The study adhered to the guidelines set by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Details of the PROSPERO protocol can be found in Supplementary Table 1.

Diaphragmatic Ultrasonography in Sports Performance: A Systematic Review

This paper aims to investigate and analyze the correlation between diaphragmatic parameters through ultrasonography and sports performance in various sports disciplines. This systematic review followed the PRISMA methodology. The search strategy was applied in the Medline database through Ovid, EMBASE, LILACS, the Cochrane Central Register of Controlled Trials, and Open Gray. Clinical trials, cohort, case-control, and cross-sectional studies were included, and animal experiments were excluded. A total of 388 studies were identified. After removing duplicates and screening titles and abstracts, sixteen studies were selected for full review, and six were included in the qualitative analysis. The results demonstrated a positive correlation between diaphragm excursion and thickness during inspiration with the anaerobic power, highlighting their importance in high-intensity performance. Additionally, one study reported a positive correlation between diaphragm thickness and aerobic power, suggesting the need for further research. The impact of inspiratory muscle training in Paralympic athletes was also evaluated, providing valuable insights into diaphragmatic adaptation in disabled populations. Ultrasonography is a feasible tool for evaluating the structure and function of the diaphragm, the main element of the respiratory process during sports practice. Its use could contribute to the evaluation and planning of sports training and be a possible indicator of performance improvement.

Exploring ultrasonographic diaphragmatic function in perioperative anesthesia setting: A comprehensive narrative review

The ultrasound study of diaphragm function represents a valid method that has been extensively studied in recent decades in various fields, especially in intensive care, emergency, and pulmonology settings. Diaphragmatic function is pivotal in these contexts due to its crucial role in respiratory mechanics, ventilation support strategies, and overall patient respiratory outcomes. Dysfunction or weakness of the diaphragm can lead to respiratory failure, ventilatory insufficiency, and prolonged mechanical ventilation, making its assessment essential for patient management and prognosis in critical care and emergency medicine. While several studies have focused on diaphragmatic functionality in the context of intensive care, there has been limited attention within the field of anesthesia. The ultrasound aids in assessing diaphragmatic dysfunction (DD) by measuring muscle mass and contractility and their potential variations over time. Recent advancements in ultrasound imaging allow clinicians to evaluate diaphragm function and monitor it during mechanical ventilation more easily. In the context of anesthesia, early studies have shed light on the patho-physiological mechanisms of diaphragm function during general anesthesia. In contrast, more recent research has centered on evaluating diaphragmatic functionality at various phases of general anesthesia and by comparing diverse types of procedures or anatomical position during surgery. The objectives of this current review are to highlight the use of diaphragm ultrasound for the evaluation of diaphragmatic function during perioperative anesthesia and surgery. Specifically, we aim to examine the effects of anesthetic agents, surgical techniques, and anatomical positioning on diaphragmatic function. We explore how ultrasound aids in assessing DD by measuring muscle mass and contractility, as well as their potential variations over time. Additionally, we will discuss recent advancements in ultrasound imaging that allow clinicians to evaluate diaphragm function and monitor it during mechanical ventilation more easily.

Diaphragm muscle parameters as a predictive tool for weaning critically ill patients from mechanical ventilation: a systematic review and meta-analysis study

Diaphragmatic ultrasound, valued for its portability and safety, assesses both structural and functional aspects of the diaphragm. While some studies support its predictive value, others conflict. This meta-analysis aims to clarify diaphragmatic ultrasound's role in predicting successful liberation from mechanical ventilation in intensive care settings. A systematic search was performed on Web of Science, Scopus, and PubMed up to March, 2024. The search strategy included a combination of relevant medical subject heading (MeSH) terms and relevant keywords. We defined our eligibility criteria based on the PICO framework. Two authors performed the data extraction using a standardized sheet. The pooled mean difference was calculated using random effects model and Hedges' g along with SD estimation. R and RStudio were used for the statistical analysis and creating forest and funnel plots. The pooled mean difference was 7.25 (95% CI: 4.20, 10.21) for DE among the two groups. We found a statistically significant difference between the two groups indicating that those with successful weaning from intubation had higher means of DE compared to those with failed weaning attempt (p-value<0.01). The mean difference of DTF was also higher among those with successful weaning from intubation compared to those with failed weaning attempt with the pooled mean difference of 14.52 (95% CI: 10.51, 18.54, p-value<0.01). The mean difference of RSBI was lower among those with successful weaning from intubation compared to those with failed weaning attempt with the pooled mean difference of -28.86 (95% CI: -41.82, -15.91, p-value<0.01). Our results suggest that evaluating diaphragmatic excursion and thickening fraction can reliably anticipate successful liberation from mechanical ventilation. However, significant heterogeneity was present among the included studies. High-quality research, particularly randomized clinical trials, is required to further elucidate the role of diaphragmatic ultrasound in predicting weaning from mechanical ventilation.

Effects of proprioceptive neuromuscular facilitation combined with threshold inspiratory muscle training on respiratory function in neurocritical patients with weaning failure: a randomized controlled trial

The purpose of this study was to determine the effects of combining proprioceptive neuromuscular facilitation (PNF) with threshold inspiratory muscle training (TIMT), compared with TIMT alone, on respiratory function in neurocritical patients who experienced a weaning failure. Forty-seven participants (mostly after a stroke), were randomly divided into the experimental group ( n  = 24) and the control group ( n  = 23). The control group received usual care and TIMT, whereas the experimental group, in addition, underwent four 90-s periods of manual PNF. Both groups performed training in the ICU twice a day for 5 consecutive days. The main outcome measures included maximum inspiratory pressure, diaphragmatic excursions, diaphragm thickening fraction, oxygenation index, and forced expiratory volume in 1 s/forced vital capacity. The results showed a significant group-by-time interaction effect for maximum inspiratory pressure [ F (1, 45) = 17.84, η2  = 0.328, P  < 0.001] and oxygenation index [ F [1, 45) = 5.58, η2  = 0.11, P  = 0.023]. When compared with the control group, the experimental group showed overall significantly higher maximum inspiratory pressure [mean difference = 4.37 cm H 2 O, 95% confidence interval (CI) 0.25-8.50, P  = 0.038]. No other significant group differences were found. Combining PNF with TIMT may improve respiratory function in neurocritical patients with weaning failure. This combination approach may increase the likelihood of survival of neurocritical patients in the ICU.

Intercostal Muscle Function During Noninvasive Ventilation and Acute Hypercapnic Respiratory Failure

BACKGROUND

Noninvasive ventilation (NIV) is a widely used and well-established treatment modality for respiratory failure. In patients with increased respiratory work of breathing, accessory muscles are commonly activated along with the diaphragm. Whereas diaphragm ultrasound has been utilized to assess outcomes of mechanical ventilation, the data on intercostal muscle ultrasound remain limited. We aimed to investigate the association between intercostal muscle thickening fraction (TF) and NIV failure in critical care patients with hypercapnic respiratory failure.

METHODS

Critical care subjects receiving NIV for hypercapnic respiratory failure were enrolled in the study. The intercostal muscle TF was measured on admission day (day 0) and the following day (day 1). NIV failure was defined as the need for invasive mechanical ventilation or death during NIV therapy.

RESULTS

A total of 158 subjects were enrolled, and 30 experienced NIV failure. Age, sex, and body mass index (BMI) were similar in the NIV success and failure groups. Acute Physiology And Chronic Health Evaluation II (APACHE II) and the Sequential Organ Failure Assessment (SOFA) scores were higher in the NIV failure group. In terms of causes of respiratory failure, the COPD exacerbation rate was higher in the NIV success group. TF was higher in the NIV failure group on both day 0 and day 1. The increased TF on the ICU admission day, with a cutoff value of 12%, was associated with NIV failure after adjusting for age, sex, BMI, APACHE II, and SOFA. Persistence of a higher TF value on both day 0 and day 1 was also associated with NIV failure risk.

CONCLUSIONS

There was a positive relation between intercostal muscle TF measured by ultrasound and NIV failure, even after adjusting for APACHE II and SOFA scores.

Diaphragm Ultrasound in Different Clinical Scenarios: A Review with a Focus on Older Patients

Diaphragm muscle dysfunction is increasingly recognized as a fundamental marker of several age-related diseases and conditions including chronic obstructive pulmonary disease, heart failure and critical illness with respiratory failure. In older individuals with physical frailty and sarcopenia, the loss of muscle mass and function may also involve the diaphragm, contributing to respiratory dysfunction. Ultrasound has recently emerged as a feasible and reliable strategy to visualize diaphragm structure and function. In particular, it can help to predict the timing of extubation in patients undergoing mechanical ventilation in intensive care units (ICUs). Ultrasonographic evaluation of diaphragmatic function is relatively cheap, safe and quick and can provide useful information for real-time monitoring of respiratory function. In this review, we aim to present the current state of scientific evidence on the usefulness of ultrasound in the assessment of diaphragm dysfunction in different clinical settings, with a particular focus on older patients. We highlight the importance of the qualitative information gathered by ultrasound to assess the integrity, excursion, thickness and thickening of the diaphragm. The implementation of bedside diaphragm ultrasound could be useful for improving the quality and appropriateness of care, especially in older subjects with sarcopenia who experience acute respiratory failure, not only in the ICU setting.

The Role of Ultrasonography in the Process of Weaning from Mechanical Ventilation in Critically Ill Patients

Weaning patients from mechanical ventilation (MV) is a complex process that may result in either success or failure. The use of ultrasound at the bedside to assess organs may help to identify the underlying mechanisms that could lead to weaning failure and enable proactive measures to minimize extubation failure. Moreover, ultrasound could be used to accurately identify pulmonary diseases, which may be responsive to respiratory physiotherapy, as well as monitor the effectiveness of physiotherapists' interventions. This article provides a comprehensive review of the role of ultrasonography during the weaning process in critically ill patients.

Ultrasonography to Access Diaphragm Dysfunction and Predict the Success of Mechanical Ventilation Weaning in Critical Care: A Narrative Review

INTRODUCTION

Weaning failure is common in mechanically ventilated patients, and whether ultrasound (US) can predict weaning outcome remains controversial. This review aims to evaluate the diaphragmatic function measured by US as a predictor of weaning outcome.

METHODS

PubMed was searched to identify original articles about the use of diaphragmatic US in ICU patients. A total of 61 citations were retrieved initially; available data of 26 studies were included in this review.

RESULTS

To assess diaphragmatic dysfunction in adults, six studies evaluated excursion, five evaluated thickening fraction, and both in nine. Despite heterogeneity in the diagnostic accuracy of diaphragm US among the studies, the sonographic indices showed good diagnostic performance for predicting weaning outcome.

CONCLUSIONS

Diaphragmatic US can be a useful and accurate tool to detect diaphragmatic dysfunction in critically ill patients and predict weaning outcome.

Replacement of fluoroscopy by ultrasonography in the evaluation of hemidiaphragm function, an exploratory prospective study

INTRODUCTION

Dysfunction of the diaphragm may ultimately lead to respiratory insufficiency and compromise patient outcome. Evaluation of diaphragm function is cumbersome. Fluoroscopy has been the gold standard to measure diaphragmatic excursion. Ultrasonography can visualize diaphragm excursion and holds many advantages such as no radiation exposure, increased portability and accessibility. However, correlation between fluoroscopy and ultrasonography has never been studied. We aimed to compare fluoroscopic and ultrasound measures of diaphragm excursion to determine if ultrasonography can replace fluoroscopy.

METHODS

We performed ultrasound and fluoroscopy simultaneously during sniff inspiration and at total inspiratory capacity in patients with chronic obstructive pulmonary disease, heart failure and in healthy volunteers. Cranio-caudal excursion was measured by fluoroscopy and compared directly to M-mode excursion, B-mode excursion, area change, resting thickness, thickening fraction and contraction velocity measured by ultrasonography.

RESULTS

Forty-two participants were included. The Pearson correlation between M-mode and fluoroscopy excursion was 0.61. The slope was 0.9 (90%CI 0.76-1.04) in a regression analysis. Using the Bland-Altman method, the bias was - 0.39 cm (95% CI - 1.04-0.26), p = 0.24. The Pearson correlation between fluoroscopy and B-mode and area change ultrasonography was high; low for thickness and fraction. All correlations were lower during sniff inspiration compared with inspiratory capacity breathing.

CONCLUSION

Ultrasonography has an acceptable correlation and bias compared to fluoroscopy and can thus be used as the primary tool to evaluate diaphragm excursion.

The combined use of parasternal intercostal muscle thickening fraction and P0.1 for prediction of weaning outcomes

BACKGROUND

A variety of parameters and diaphragmatic ultrasound in ventilator weaning has been studied extensively, and the findings yield inconsistent conclusions. The parasternal intercostal muscle holds important substantial respiratory reserve capacity when the central drive is enhanced, the predictive value of combining parasternal intercostal muscle ultrasound parameters with P0.1(airway occlusion pressure at 100 msec) in assessing ventilator weaning outcomes is still unknown.

OBJECTIVES

Our study aimed to evaluate the predictive efficacy of parasternal intercostal muscle ultrasound in conjunction with P0.1 in determining weaning failure.

METHODS

We recruited patients who had been admitted to ICU and had been receiving mechanical ventilation for over two days. All patients underwent a half-hour spontaneous breathing trial (SBT) with low-level pressure support ventilation (PSV). They were positioned semi-upright for parasternal intercostal muscle ultrasound evaluations, including parasternal intercostal muscle thickness (PIMT), and parasternal intercostal muscle thickening fraction (PIMTF); P0.1 was obtained from the ventilator. Weaning failure was defined as the need for non-invasive positive pressure ventilation or re-intubation within 48 h post-weaning.

RESULTS

Of the 56 enrolled patients with a mean age of 63.04 ± 15.80 years, 13 (23.2%) experienced weaning failure. There were differences in P0.1 (P = .001) and PIMTF (P = .017) between the two groups, but also in patients with a diaphragm thickness ≥ 2 mm. The predictive threshold values were PIMTF ≥ 13.15% and P0.1 ≥ 3.9 cmH2O for weaning failure. The AUROC for predicting weaning failure was 0.721 for PIMTF, 0.792 for P0.1, and 0.869 for the combination of PIMTF and P0.1.

CONCLUSIONS

The parasternal intercostal muscle thickening fraction and P0.1 are independently linked to weaning failure, especially in patients with normal diaphragm thickness. The combination of parasternal intercostal muscle thickening fraction and P0.1 can serve as a valuable tool for the precise clinical prediction of weaning outcomes.

TRIAL REGISTRATION

Chinese Clinical Trial Registry website (ChiCTR2200065422).

Value of Diaphragm Ultrasonography for Extubation: A Single-Blinded Randomized Clinical Trial

Introduction

Daily evaluation of mechanically ventilated (MV) patients is essential for successful extubation. Proper withdrawal prevents complications and reduces the cost of hospitalization in the intensive care unit (ICU). Diaphragm ultrasonography (DUS) has emerged as a potential instrument for determining whether a patient is ready to be extubated. This study compared the efficacy rate of extubation using a standard withdrawal protocol and DUS in patients with MV.

Methods

A randomized, parallel, single-blind, controlled study was conducted on ICU patients undergoing MV. Patients were randomly assigned to either the control (conventional weaning protocol) group or intervention (DUS-guided weaning) group in a 1 : 1 ratio. The primary outcome measure was the rate of reintubation and hospital mortality.

Results

Forty patients were randomized to the trial. The mean age of the sample was 70 years, representing an older population. The extubation success rate was 90% in both groups. There was no reintubation in the first 48 hours and only two reintubations in both groups between the second and seventh days. The hospital mortality risk in patients with acute kidney injury was positively correlated with age and the need for hemodialysis. Discussion. This study demonstrates the usefulness of DUS measurement protocols for withdrawing MV. The rate of reintubation was low for both cessation methods. As a parameter, the diaphragm thickness fraction comprehensively evaluates the diaphragm function. The results demonstrate that DUS has the potential to serve as a noninvasive tool for guiding extubation decisions. In conclusion, using DUS in patients with respiratory failure revealed no difference in reintubation rates or mortality compared with the conventional method. Future research should concentrate on larger, multicentered, randomized trials employing a multimodal strategy that combines diaphragmatic parameters with traditional clinical withdrawal indices.

Role of ultrasound in acute respiratory failure and in the weaning of mechanical ventilation

Comprehensive ultrasound assessment has become an essential tool to facilitate the diagnosis and therapeutic management of critically ill patients with acute respiratory failure (ARF). There is evidence supporting the use of ultrasound for the diagnosis of pneumothorax, acute respiratory distress syndrome, cardiogenic pulmonary edema, pneumonia and acute pulmonary thromboembolism, and in patients with COVID-19. In addition, in recent years, the use of ultrasound to evaluate responses to treatment in critically ill patients with ARF has been developed, providing a noninvasive tool for titrating positive end-expiratory pressure, monitoring recruitment maneuvers and response to prone position, as well as for facilitating weaning from mechanical ventilation. The objective of this review is to summarize the basic concepts on the utility of ultrasound in the diagnosis and monitoring of critically ill patients with ARF.

Ultrasonographic Assessment of Diaphragmatic Function and Its Clinical Application in the Management of Patients with Acute Respiratory Failure

Acute respiratory failure (ARF) is a common life-threatening medical condition, with multiple underlying etiologies. In these cases, many factors related to systemic inflammation, prolonged use of steroids, and lung mechanical abnormalities (such as hyperinflation or increased elastic recoil due to pulmonary oedema or fibrosis) may act as synergic mechanisms leading to diaphragm dysfunction. The assessment of diaphragm function with ultrasound has been increasingly investigated in the emergency department and during hospital stay as a valuable tool for providing additional anatomical and functional information in many acute respiratory diseases. The diaphragmatic ultrasound is a noninvasive and repeatable bedside tool, has no contraindications, and allows the physician to rapidly assess the presence of diaphragmatic dysfunction; this evaluation may help in estimating the need for mechanical ventilation (and the risk of weaning failure), as well as the risk of longer hospital stay and higher mortality rate. This study presents an overview of the recent evidence regarding the evaluation of diaphragmatic function with bedside ultrasound and its clinical applications, including a discussion of real-life clinical cases.