Diaphragmatic ultrasonography for predicting ventilator weaning: A meta-analysis

Systematic review and meta-analysis of the diagnostic performance of lacrimal gland ultrasound elastography in primary Sjögren's syndrome

OBJECTIVE

This research conducted a comprehensive evaluation of the effectiveness of ultrasonic elastography (USE) in detecting lacrimal gland involvement in individuals suffering from primary Sjögren's syndrome (pSS).

METHODS

A comprehensive search was undertaken across multiple databases including PubMed, the Cochrane Library, EMBASE, Wanfang, Web of Science, and the Chinese National Knowledge Infrastructure, to gather relevant literature pertaining to the application of USE in diagnosing pSS from January 1, 2000, to October 1, 2023. Pooled data were used to calculate sensitivity, specificity, and diagnostic odds ratios. Several summary metrics were used to evaluate SWE's performance in detecting pSS, including the area under the receiver operating characteristic curve, diagnostic odds ratios, sensitivities, and specificities.

RESULTS

Five pertinent studies included a total of 273 patients. Shear wave elastography (SWE) demonstrated a pooled sensitivity of 0.88 (95% CI 0.77-0.94) and specificity of 0.94 (95% CI 0.88-0.98), with an area under the receiver operating characteristic curve of 0.97 (95% CI 0.95-0.98). SWE exhibited a positive likelihood ratio of 15.86 (95% CI 6.99-36.00) and a negative likelihood ratio of 0.13 (95% CI 0.07-0.25). No evidence of publication bias was observed (p = 0.70).

CONCLUSION

SWE demonstrates a remarkable degree of precision in detecting lacrimal gland involvement in individuals suffering from pSS.

[EXTUBATION FAILURE IN BURNS: INCIDENCE, RISK FACTORS AND PROGNOSIS]

The incidence of extubation failure varies between 2 and 25% depending on the studied population. Few studies have been conducted in burn victims. To determine the incidence, causes, risk factors and outcome of burned patients after a failed extubation, a retrospective single-center case-control study was conducted over a period of 3 years (January 2018-December 2021). All burned patients aged over 16, ventilated for at least 24 hours and having had at least one extubation attempt were included. Extubation failure was defined as the need for re-intubation within 48 hours. Eighty-eight patients had planned extubation. These patients were divided into 2 groups comparable in terms of age and sex. Failure group: including patients with failed extubation (N= 34) and a success group (N= 64) including patients who succeeded. The incidence of extubation failure was 36.6%. Hypophosphatemia, anemia <8g/dl, duration of mechanical ventilation of 8,5 days and abundant secretions during extubation were identified as risk factors for extubation failure (p<0.05). The main cause of failure was retention of secretion (50%). Extubation failure was associated with prolonged length of stay (34 vs. 19 days, P= 0.005), increased infectious complications (P=0.007) and mortality rate (79.4%, 1.5%, P<0.001).

Predictive value of fluid balance before extubation on its outcome in mechanically ventilated adults in the intensive care unit

BACKGROUND

Although there are many reasons for extubation failure, maintaining negative or lower positive fluid balances 24 hours before extubation may be a key measure for successful extubation.

AIM

To assess the predictive value of fluid balance before extubation and its outcome in mechanically ventilated cases in the intensive care unit (ICU).

STUDY DESIGN

This retrospective cohort study involved collecting clinical data from patients undergoing mechanical ventilation in Lanzhou general adult ICU from January 2022 to December 2022. Based on extubation outcomes, the patients were divided into a successful extubation group and a failed extubation group. Their fluid balance levels 24 h before extubation were compared with analyse the predictive value of fluid balance on extubation outcomes in patients undergoing mechanical ventilation.

RESULTS

In this study, clinical data from 545 patients admitted to a general adult ICU were collected. According to the inclusion and exclusion criteria, 265 (48.6%) patients were included, of which 197 (74.3%) were successfully extubated; extubation was unsuccessful in 68 (25.7%) patients. The total intake and fluid balance levels in patients in the failed extubation group 24 h before extubation were significantly higher than those in the successful extubation group, with a median of 2679.00 (2410.44-3193.50) mL versus 2435.40 (1805.04-2957.00) mL, 831.50 (26.25-1407.94) mL versus 346.00 (-163.00-941.50) mL. Receiver operating characteristic (ROC) curve analysis showed that the optimal cut-off value for predicting extubation outcomes was 497.5 mL (sensitivity 64.7%, specificity 59.4%) for fluid balance 24 h before extubation. The area under the ROC curve was 0.627 (95% confidence interval [CI] 0.547-0.707). Based on the logistic regression model, cumulative fluid balance >497.5 mL 24 h before extubation could predict its outcomes in mechanically ventilated patients in the ICU (OR = 5.591, 95% CI [2.402-13.015], p < .05).

CONCLUSIONS

The fluid balance level 24 h before extubation was correlated with the outcome of extubation in mechanically ventilated patients in the ICU. The risk of extubation failure was higher when the fluid balance level was >497.5 mL.

RELEVANCE TO CLINICAL PRACTICE

Tracheal intubation is a crucial life support technique for many critically ill patients, and determining the appropriate time for extubation remains a challenge for clinicians. Although there are many reasons for extubation failure, acute pulmonary oedema caused by continuous positive fluid balance and volume overload is one of the main reasons for extubation failure. Therefore, it is very important to study the relationship between fluid balance and extubation outcome to improve the prognosis of patients with invasive mechanical ventilation in ICU.

Diaphragm ultrasound in patients with prolonged weaning from mechanical ventilation

Background

Several publications have examined diaphragmatic ultrasound using two-dimensional (2D) parameters in the context of weaning from mechanical ventilation (MV) and extubation. However, the studied cohorts had rather short duration of ventilation. Examinations on patients with prolonged weaning after long-term ventilation were missing. It was the aim of this study to assess of the diaphragm and peripheral musculature of patients undergoing prolonged weaning creating a chronological sequence of ultrasonic parameters during the course of weaning.

Methods

This study was carried out as a monocentric, prospective observational cross-sectional study. Patients in prolonged weaning who were transferred to a specialized weaning unit were eligible for inclusion if they were ventilated invasively by means of an endotracheal tube or tracheal cannula and if their expected treatment period was at least 5 days. Diaphragmatic function and one representative peripheral muscle were examined in 50 patients between March 2020 and April 2021. The 2D sonographic parameters of diaphragm and diaphragmatic function consisted of diaphragmatic thickness (Tdi) at the end of inspiration and expiration, the fractional thickening (FT) and the diaphragmatic excursion. Additionally, the M. quadriceps femoris was sonographically assessed at two locations. The difference of measurements between the first and the last measuring timepoint were examined using the Wilcoxon signed-rank test. For a longer chronological sequence, the Friedman's rank sum test with subsequent Wilcoxon-Nemenyi-McDonald-Thompson test for multiple comparisons was carried out.

Results

Fifty patients with prolonged weaning were included. The median duration of MV before transfer to the weaning unit was 11.5 [interquartile range (IQR) 10] days. Forty-one patients could be assessed over the full course of weaning, with 38 successfully weaned. Within these 41 patients, the sonographic parameters of the diaphragm slightly increased over the course of weaning indicating an increase in thickness and mobility. Especially parameters which represented an active movement reached statistical significance, i.e., inspiratory Tdi when assessed under spontaneous breathing [begin 3.41 (0.99) vs. end 3.43 (1.31) mm; P=0.01] and diaphragmatic excursion [begin 0.7 (0.8) vs. end 0.9 (0.6) cm; P=0.01]. The presence of positive end-expiratory pressure (PEEP) and pressure support did not influence the sonographic parameters significantly. The M. quadriceps femoris, in contrast, decreased slightly but constantly over the time [lower third: begin 1.36 (0.48) vs. end 1.28 (0.36) cm; P=0.054].

Conclusions

The present study is the first one to longitudinally analyse diaphragmatic ultrasound in patients with prolonged weaning. Sonographic assessment showed that Tdi and excursion increased over the course of prolonged weaning, while the diameter of a representative peripheral muscle decreased. However, the changes are rather small, and data show a wide dispersion. To allow a potential, standardized use of diaphragm ultrasound for diagnostic decision support in prolonged weaning, further studies in this specific patient group are required.

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.

Diaphragm Ultrasonography: Reference Values and Influencing Factors for Thickness, Thickening Fraction, and Excursion in the Seated Position

INTRODUCTION

Measurements of diaphragm function by ultrasonography are affected by body position, but reference values in the seated position have not been established for an Asian population. This study aimed to determine reference values for diaphragm thickness, thickening fraction, and dome excursion by ultrasonography and to investigate the effects of sex, height, and body mass index.

METHODS

Diaphragm ultrasonography was performed on 109 seated Japanese volunteers with normal respiratory function who were enrolled between March 2022 and January 2023. Thickness, thickening fraction, and excursion were measured. Reference values and the measurement success rate were calculated. Multivariate analysis adjusted for sex, height, and body mass index was performed.

RESULTS

The measurement success rate was better for thickness than for excursion. The mean (lower limit of normal) values on the right/left sides were as follows. During quiet breathing, thickness at end expiration(mm) was 1.7 (0.9)/1.6 (0.80), thickening fraction(%) was 50 (0.0)/52 (0.0), and excursion(cm) was 1.7 (0.5)/1.9 (0.5). During deep breathing, the thickening fraction was 111 (24)/107 (22), and the excursion was 4.4 (1.7)/4.1 (2.0). In multivariate analysis, body mass index was positively associated with thickness but not with the thickening fraction.

CONCLUSION

The reference values in this study were smaller than those in previous reports from Europe. Considering that thickness is influenced by body mass index, using Western reference values in Asia, where the average body mass index is lower, might not be appropriate. The thickening fraction in deep breathing is unaffected by other items and can be used more universally.

Correlation Between Diaphragmatic Excursion and Exercise Tolerance Improvement Following Pulmonary Rehabilitation in Patients with Chronic Obstructive Pulmonary Disease-Obstructive Sleep Apnea Overlap Syndrome

Purpose

We assess the predictive value of diaphragm excursion (DE) in enhancing exercise tolerance following pulmonary rehabilitation (PR) among patients with COPD-OSA overlap syndrome.

Material and Methods

This prospective cohort study enrolled 63 patients diagnosed with COPD-OSA overlap syndrome who actively participated in a PR program from January 2021 to May 2023. Among these, 58 patients successfully completed the 20-week PR program, with exercise tolerance assessed through the measurement of six-minute walk distance (6MWD), and DE evaluated by ultrasonography. The responder to PR in terms of exercise ability was defined as a patient who showed an increase of >30m in 6MWD. The cutoff value for predicting PR response based on DE was determined using receiver operating characteristic (ROC) curves.

Results

Following the PR program, significant improvements were observed in mMRC, 6MWD, DE during deep breathing, and diaphragm thickness fraction (DTF). Of the participants, 33 patients (57%) were classified as responders, while 25 patients (43%) were considered non-responders. Baseline values of FEV1% predicted, 6MWD, DE during deep breathing, DTF, and PaO2 exhibited a significant elevation in responders as compared to non-responders. The changes of 6MWD were positively associated with the baseline values of DTF and DE during deep breathing, FEV1% predicted and PaO2, while negatively correlated with baseline value of mMRC. The predictive performance in terms of the area under the ROC curve for determining responder's DTF was found to be 0.769, accompanied by a sensitivity of 85% and specificity of 68%, using a cutoff value at 17.26%. Moreover, it was observed that DE during deep breathing could predict the area under the ROC curve for responders to be 0.753, with a sensitivity of 91% and specificity of 56% at a cutoff value of 3.61cm.

Conclusion

Diaphragm excursion serves as a valuable predictor for determining the enhancement of exercise tolerance following PR in patients with COPD-OSA overlap syndrome.

Trial Registration

ChiCTR1800020257, www.chictr.org.cn/index.aspx.

Effects of transcutaneous electrical diaphragmatic stimulation in critically ill elderly patients: a randomized controlled trial

BACKGROUND

Elderly patients under invasive mechanical ventilation (IMV) are more susceptible to muscle weakness. In the out-of-hospital environment, there are benefits to transcutaneous electrical diaphragmatic stimulation (TEDS), which is an easy-to-apply and low-cost technique.

OBJECTIVE

To evaluate the effect of TEDS on respiratory muscle strength, diaphragm thickness (DT), and IMV time in critically ill elderly patients.

METHODS

This was a randomized controlled trial in which patients were divided into an experimental group (EG) and a control group (CG). TEDS started 24 h after orotracheal intubation and lasted until the end of weaning. Both groups underwent the following assessments during the spontaneous breathing test after weaning from mechanical ventilation (MV): measurement of respiratory muscle strength by pressure gauge, analysis of DT by lung ultrasound, and extubation failure prevention checklist.

RESULTS

There were 23 participants in the EG and 21 in the CG. The median age was 66 (60-79) years. The mean values of the diaphragmatic thickening index in the EG and CG participants were 99.13 ± 26.75 and 66.88 ± 31.77, respectively (p = .001, Cohen's d = 1.094). The mean values of maximum inspiratory pressure in the EG and CG were 22.04 ± 3.41 and 19.34 ± 4.23 cmH2O, respectively (p = .005, Cohen's d = 0.698). The Tobin index and the integrative weaning index were similar between groups (p = .584 and p = .102, respectively). The duration of MV in the EG and CG was 6.28 ± 2.68 and 9.21 ± 2.76 days, respectively (p = .001, Cohen's d = -1.075).

CONCLUSION

Critically ill elderly patients receiving TEDS had shorter MV time, greater inspiratory muscle strength, and greater diaphragmatic contraction capacity according to their thickness fraction.

Comparing lung aeration and respiratory effort using two different spontaneous breathing trial: T-piece vs pressure support ventilation

OBJECTIVE

To assess the changes in lung aeration and respiratory effort generated by two different spontaneous breathing trial (SBT): T-piece (T-T) vs pressure support ventilation (PSV).

DESIGN

Prospective, interventionist and randomized study.

SETTING

Intensive Care Unit (ICU) of Hospital del Mar.

PARTICIPANTS

Forty-three ventilated patients for at least 24 h and considered eligible for an SBT were included in the study between October 2017 and March 2020.

INTERVENTIONS

30-min SBT with T-piece (T-T group, 20 patients) or 8-cmH2O PSV and 5-cmH2O positive end expiratory pressure (PSV group, 23 patients).

MAIN VARIABLES OF INTEREST

Demographics, clinical data, physiological variables, lung aeration evaluated with electrical impedance tomography (EIT) and lung ultrasound (LUS), and respiratory effort using diaphragmatic ultrasonography (DU) were collected at different timepoints: basal (BSL), end of SBT (EoSBT) and one hour after extubation (OTE).

RESULTS

There were a loss of aeration measured with EIT and LUS in the different study timepoints, without statistical differences from BSL to OTE, between T-T and PSV [LUS: 3 (1, 5.5) AU vs 2 (1, 3) AU; p = 0.088; EELI: -2516.41 (-5871.88, 1090.46) AU vs -1992.4 (-3458.76, -5.07) AU; p = 0.918]. Percentage of variation between BSL and OTE, was greater when LUS was used compared to EIT (68.1% vs 4.9%, p ≤ 0.001). Diaphragmatic excursion trend to decrease coinciding with a loss of aeration during extubation.

CONCLUSION

T-T and PSV as different SBT strategies in ventilated patients do not show differences in aeration loss, nor estimated respiratory effort or tidal volume measured by EIT, LUS and DU.

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.

Accuracy of lung and diaphragm ultrasound in predicting infant weaning outcomes: a systematic review and meta-analysis

Background

Although lung and diaphragm ultrasound are valuable tools for predicting weaning results in adults with MV, their relevance in children is debatable. The goal of this meta-analysis was to determine the predictive value of lung and diaphragm ultrasound in newborn weaning outcomes.

Methods

For eligible studies, the databases MEDLINE, Web of Science, Cochrane Library, PubMed, and Embase were thoroughly searched. The Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) method was used to evaluate the study's quality. Results were gathered for sensitivity, specificity, diagnostic odds ratio (DOR), and the area under the curve of summary receiver operating characteristic curves (AUSROC). To investigate the causes of heterogeneity, subgroup analyses and meta-regression were conducted.

Results

A total of 11 studies were suitable for inclusion in the meta-analysis, which included 828 patients. The pooled sensitivity and specificity of lung ultrasound (LUS) were 0.88 (95%CI, 0.85-0.90) and 0.81 (95%CI, 0.75-0.87), respectively. The DOR for diaphragmatic excursion (DE) is 13.17 (95%CI, 5.65-30.71). The AUSROC for diaphragm thickening fraction (DTF) is 0.86 (95%CI, 0.82-0.89). The most sensitive and specific method is LUS. The DE and DTF were the key areas where study heterogeneity was evident.

Conclusions

Lung ultrasonography is an extremely accurate method for predicting weaning results in MV infants. DTF outperforms DE in terms of diaphragm ultrasound predictive power.

Clinical utility of diaphragmatic ultrasonography for mechanical ventilator weaning in adults: A study protocol for systematic review and meta-analysis

Background and Aims

Mechanical ventilation is associated with several risks, including barotrauma, ventilator-associated pneumonia, and ventilator-induced diaphragmatic dysfunction. A delay in weaning from mechanical ventilation increases these risks, and prolonged weaning has been shown to increase hospital mortality. Various tools have been used in clinical practice to predict successful weaning from mechanical ventilation; however, they have a low prognostic accuracy. The use of ultrasonography in intensive care units is an area of growing interest since it is a noninvasive, convenient, and safe modality. Since ultrasonography can provide real-time assessment of diaphragmatic morphology and function, it may have clinical utility in predicting successful mechanical ventilator weaning. This study aimed to describe a protocol to assess the effectiveness of diaphragmatic ultrasonography in the decision-making process for ventilator weaning in terms of its impact on clinical outcomes.

Methods

This systematic review of published analytical research will use an aggregative thematic approach according to the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols guidelines. We will perform a comprehensive search for studies on the MEDLINE, Embase, and Cochrane Central Register of Controlled Trials databases. Two authors will independently perform abstract and full-text screening and data extraction. Additionally, a meta-analysis and the risk of bias evaluation will be conducted, as appropriate.

Conclusion

Systematic reviews on the effectiveness of diaphragmatic ultrasonography in the decision-making process for ventilator weaning in terms of its impact on clinical outcomes are lacking. The results of this systematic review may serve as a basis for future clinical trials. Systematic review registration: This protocol was registered with the Open Science Framework: https://osf.io/cn8xf.

Effectiveness of diaphragmatic ultrasound as a predictor of successful weaning from mechanical ventilation: a systematic review and meta-analysis

BACKGROUND

Several measurements have been used to predict the success of weaning from mechanical ventilation; however, their efficacy varies in different studies. In recent years, diaphragmatic ultrasound has been used for this purpose. We conducted a systematic review and meta-analysis to evaluate the effectiveness of diaphragmatic ultrasound in predicting the success of weaning from mechanical ventilation.

METHODS

Two investigators independently searched PUBMED, TRIP, EMBASE, COCHRANE, SCIENCE DIRECT, and LILACS for articles published between January 2016 and July 2022. The methodological quality of the studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool; additionally, the certainty of the evidence is evaluated using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) methodology. Sensitivity and specificity analysis was performed for diaphragmatic excursion and diaphragmatic thickening fraction; positive and negative likelihood ratios and diagnostic odds ratios (DOR) with their confidence intervals (95% CI) were calculated by random effects analysis, summary receiver operating characteristic curve was estimated. Sources of heterogeneity were explored by subgroup analysis and bivariate meta-regression.

RESULTS

Twenty-six studies were included, of which 19 were included in the meta-analysis (1204 patients). For diaphragmatic excursion, sensitivity was 0.80 (95% CI 0.77-0.83), specificity 0.80 (95% CI 0.75-0.84), area under the summary receiver operating characteristic curve 0.87 and DOR 17.1 (95% CI 10.2-28.6). For the thickening fraction, sensitivity was 0.85 (95% CI 0.82-0.87), specificity 0.75 (95% CI 0.69-0.80), area under the summary receiver operating characteristic curve 0.87 and DOR 17.2 (95% CI 9.16-32.3). There was heterogeneity among the included studies. When performing a subgroup analysis and excluding studies with atypical cutoff values, sensitivity and specificity increased for diaphragmatic thickening fraction; sensitivity increased and specificity decreased for diaphragmatic excursion; when comparing studies using pressure support (PS) versus T-tube, there was no significant difference in sensitivity and specificity; bivariate meta-regression analysis shows that patient position at the time of testing was a factor of heterogeneity in the included studies.

CONCLUSIONS

Measurement of diaphragmatic excursion and diaphragmatic thickening fraction predict the probability of successful weaning from mechanical ventilation with satisfactory diagnostic accuracy; however, significant heterogeneity was evident in the different included studies. Studies of high methodological quality in specific subgroups of patients in intensive care units are needed to evaluate the role of diaphragmatic ultrasound as a predictor of weaning from mechanical ventilation.

The ratio of respiratory rate to diaphragm thickening fraction for predicting extubation success

BACKGROUND

Several parameters are used to predict successful extubation but their accuracy varies among studies. We hypothesized that combining conventional and diaphragmatic parameters would be more effective than using just one. Our primary objective was to evaluate the performance of the respiratory rate in relation to the diaphragm thickening fraction (RR/DTF) ratio to predict the success of extubation.

METHODS

We enrolled 130 adult patients who required invasive mechanical ventilation, planned to be extubated, and used a spontaneous breathing trial (SBT) in the intensive care unit from July 2020 to April 2022. We measured the conventional parameters and the diaphragmatic parameters 2 h after SBT. The RR/DTF was calculated by dividing the respiratory rate (RR) by the diaphragm thickening fraction (DTF). The definition of weaning success is successful extubation within 48 h.

RESULTS

Of 130 patients, 8 patients (6.2%) were reintubated within 48 h. The RR/DTF was significantly lower in the successful extubation group than in the extubation failure group (right hemidiaphragm; 0.47 (0.33-0.64) vs 1.1 (0.6-2.32), p < 0.001 and left hemidiaphragm; 0.45 (0.31-0.65) vs 0.78 (0.48-1.75), p < 0.001). The right RR/DTF using a cut-off point at ≤ 0.81 had a sensitivity of 87.7%, a specificity of 75%, and areas under the receiver operating characteristic curve (AUROC) of 0.762 for predicting successful extubation (p = 0.013). The sensitivity, specificity, and AUROC for predicting extubation success of right DTF at a cut-off point of ≥ 26.2% were 84.3%, 62.5%, and 0.775, respectively (p = 0.009).

CONCLUSION

The RR/DTF ratio is a promising tool for predicting extubation outcome. Additionally, using RR/DTF was more reliable than conventional or diaphragmatic parameters alone in predicting extubation success.

Diaphragm Ultrasound in Critically Ill Patients on Mechanical Ventilation—Evolving Concepts

Mechanical ventilation (MV) is a life-saving respiratory support therapy, but MV can lead to diaphragm muscle injury (myotrauma) and induce diaphragmatic dysfunction (DD). DD is relevant because it is highly prevalent and associated with significant adverse outcomes, including prolonged ventilation, weaning failures, and mortality. The main mechanisms involved in the occurrence of myotrauma are associated with inadequate MV support in adapting to the patient’s respiratory effort (over- and under-assistance) and as a result of patient-ventilator asynchrony (PVA). The recognition of these mechanisms associated with myotrauma forced the development of myotrauma prevention strategies (MV with diaphragm protection), mainly based on titration of appropriate levels of inspiratory effort (to avoid over- and under-assistance) and to avoid PVA. Protecting the diaphragm during MV therefore requires the use of tools to monitor diaphragmatic effort and detect PVA. Diaphragm ultrasound is a non-invasive technique that can be used to monitor diaphragm function, to assess PVA, and potentially help to define diaphragmatic effort with protective ventilation. This review aims to provide clinicians with an overview of the relevance of DD and the main mechanisms underlying myotrauma, as well as the most current strategies aimed at minimizing the occurrence of myotrauma with special emphasis on the role of ultrasound in monitoring diaphragm function.

Ultrasonography of Diaphragm to Predict Extubation Outcome

Background and objectives An intensivist's decision, when it comes to weaning off a patient from mechanical ventilation and extubation, is based on many criteria. Problems can be associated with both prolonged ventilation and early extubation. Therefore, for optimal functioning of the diaphragm, the primary inspiratory muscle, it is important to resume spontaneous ventilation after extubation irrespective of the cause of respiratory failure. Thus, diaphragmatic parameters can prove useful in predicting the rate of success of extubation. However, till date in our institute, extubation has been done using only the standard parameters; hence, in this study, diaphragmatic parameters obtained by ultrasonography-diaphragmatic thickening fraction (dTF) and diaphragmatic excursion (DE) have been studied to predict extubation outcome. The objectives of this study are to (1) measure the diaphragmatic thickening fraction (dTF) in % and diaphragmatic excursion (DE) in cm before and after the spontaneous breathing trial (SBT) and (2) compare dTF and DE with standard extubation parameters in order to predict extubation outcome. Materials and methods This is a prospective, double-blind, observational study. The number of patients involved was 41. After obtaining ethical committee clearance, informed consent was taken from the patients' attendants. In this study, we divided doctors into the treating team and the research team. The treating team comprised the primary doctors working in the intensive care unit (ICU), and they evaluated the patients' readiness for pressure support ventilation. The research team performed diaphragmatic ultrasonography on those patients who met the inclusion criteria. The treating team was blinded to the dTF and DE results obtained by the research team. Prior to extubation, all the patients had to satisfy the standard extubation criteria followed at R. L. Jalappa Hospital and Research Centre (RLJH), Kolar Results We observed that 68.29 (%) of the patients with normal dTF and DE values and 21.95(%) with slightly lower dTF and DE values were extubated successfully, and 7.31 (%) with normal dTF and DE values were reintubated; 2.43 (%) were extubated onto non-invasive ventilation (NIV). Conclusion From our study, we have concluded that bedside ultrasonography of the diaphragm, that is the measurement of diaphragm for dTF and DE always compliments the standard criteria for extubation and can be used for weaning the patients from mechanical ventilation, as bedside ultrasonography is not only easy and convenient but also a reliable parameter in predicting the outcome of weaning, however, it cannot be used as a sole criteria.

Update on Lean Body Mass Diagnostic Assessment in Critical Illness

Acute critical illnesses can alter vital functions with profound biological, biochemical, metabolic, and functional modifications. Despite etiology, patient's nutritional status is pivotal to guide metabolic support. The assessment of nutritional status remains complex and not completely elucidated. Loss of lean body mass is a clear marker of malnutrition; however, the question of how to investigate it still remains unanswered. Several tools have been implemented to measure lean body mass, including a computed tomography scan, ultrasound, and bioelectrical impedance analysis, although such methods unfortunately require validation. A lack of uniform bedside measurement tools could impact the nutrition outcome. Metabolic assessment, nutritional status, and nutritional risk have a pivotal role in critical care. Therefore, knowledge about the methods used to assess lean body mass in critical illnesses is increasingly required. The aim of the present review is to update the scientific evidence regarding lean body mass diagnostic assessment in critical illness to provide the diagnostic key points for metabolic and nutritional support.

New International Guidelines and Consensus on the Use of Lung Ultrasound

Following the innovations and new discoveries of the last 10 years in the field of lung ultrasound (LUS), a multidisciplinary panel of international LUS experts from six countries and from different fields (clinical and technical) reviewed and updated the original international consensus for point-of-care LUS, dated 2012. As a result, a total of 20 statements have been produced. Each statement is complemented by guidelines and future developments proposals. The statements are furthermore classified based on their nature as technical (5), clinical (11), educational (3), and safety (1) statements.

Methodological and Clinimetric Evaluation of Inspiratory Respiratory Muscle Ultrasound in the Critical Care Setting: A Systematic Review and Meta-Analysis

OBJECTIVE

Significant variations exist in the use of respiratory muscle ultrasound in intensive care with no society-level consensus on the optimal methodology. This systematic review aims to evaluate, synthesize, and compare the clinimetric properties of different image acquisition and analysis methodologies.

DATA SOURCES

Systematic search of five databases up to November 24, 2021.

STUDY SELECTION

Studies were included if they enrolled at least 50 adult ICU patients, reported respiratory muscle (diaphragm or intercostal) ultrasound measuring either echotexture, muscle thickness, thickening fraction, or excursion, and evaluated at least one clinimetric property. Two independent reviewers assessed titles, abstracts, and full text against eligibility.

DATA EXTRACTION

Study demographics, ultrasound methodologies, and clinimetric data.

DATA SYNTHESIS

Sixty studies, including 5,025 patients, were included with 39 studies contributing to meta-analyses. Most commonly measured was diaphragm thickness (DT) or diaphragm thickening fraction (DTF) using a linear transducer in B-mode, or diaphragm excursion (DE) using a curvilinear transducer in M-mode. There are significant variations in imaging methodology and acquisition across all studies. Inter- and intrarater measurement reliabilities were generally excellent, with the highest reliability reported for DT (ICC, 0.98; 95% CI, 0.94-0.99). Pooled data demonstrated acceptable to excellent accuracy for DT, DTF, and DE to predicting weaning outcome after 48 to 72 hours postextubation (DTF AUC, 0.79; 95% CI, 0.73-0.85). DT imaging was responsive to change over time. Only three eligible studies were available for intercostal muscles. Intercostal thickening fraction was shown to have excellent accuracy of predicting weaning outcome after 48-hour postextubation (AUC, 0.84; 95% CI, 0.78-0.91).

CONCLUSIONS

Diaphragm muscle ultrasound is reliable, valid, and responsive in ICU patients, but significant variation exists in the imaging acquisition and analysis methodologies. Future work should focus on developing standardized protocols for ultrasound imaging and consider further research into the role of intercostal muscle imaging.

Diaphragm Evaluation and Lung Ultrasound Score during Weaning

How to cite this article: Blanco JB, Esquinas A. Diaphragm Evaluation and Lung Ultrasound Score during Weaning. Indian J Crit Care Med 2022;26(9):1054–1055.

Diaphragmatic ultrasound in weaning ventilated patients: a reliable predictor?

Timely weaning of mechanical ventilation is clinically difficult, as both early and late discontinuations are associated with adverse events impeding the patient's favorable course in the critical care unit. Many parameters aid in judging whether the patient is going to be safely extubated; however, some remain deficient. We herein describe diaphragmatic ultrasound as a new modality for this purpose, detailing diaphragm excursion and thickness as means of it.

Diaphragm Electromyography Versus Ultrasonography in the Prediction of Mechanical Ventilation Liberation Outcome

BACKGROUND

ICU-acquired diaphragm paresis occurs in about 25% of patients after prolonged mechanical ventilation. Diaphragm function can be evaluated via several approaches including monitoring of electrical activity of diaphragm (electromyography [EMG]) or ultrasound (US) measurements. We aimed to assess the usefulness of diaphragm EMG indices in predicting liberation outcome in comparison with diaphragm US measurements.

METHODS

We included consecutive subjects invasively ventilated for > 48 h for acute respiratory failure and who were considered ready to undergo a spontaneous breathing trial (SBT). Exclusion criteria were age < 18 y, pregnancy, tracheostomy, or patients with confirmed neuromuscular diseases. To start the SBT, we set pressure support to 0 cm H2O and PEEP to 5 cm H2O. During the initial 5 min of SBT, mean values of Δ electrical activity of the diaphragm (ΔEAdi) (EAdi peak - EAdi minimal), tidal volume (VT), and breathing frequency were measured. Neuroventilatory efficiency was calculated as VT divided by ΔEAdi. Rapid shallow breathing index was calculated as breathing frequency divided by VT. US examination of the diaphragm and assessment of diaphragmatic excursion (DE) and diaphragm thickening fraction (DTF) were recorded 30 min after initiation of SBT.

RESULTS

Twenty-four subjects were included; DTF predicted weaning failure with area under the curve 0.96 and P value < .001 with sensitivity 100% and specificity 94% for the cutoff value ≤ 15%. DE for the cutoff ≤ 1.56 cm showed sensitivity 75% and specificity 69%, whereas ΔEAdi with cutoff value ≤ 4 μV showed sensitivity 25% and specificity 100%. Neuroventilatory efficiency with cutoff value ≤ 29 mL/μV showed sensitivity 50% and specificity 81%. All 3 parameters showed nonsignificant results with area under the curve 0.73, 0.56, and 0.62 and P values .08, .65, and .34, respectively.

CONCLUSIONS

Diaphragm EMG indices were inferior to diaphragm ultrasonography in prediction of mechanical ventilation liberation outcome.

Visual Rounds Based on Multiorgan Point-of-Care Ultrasound in the ICU

Point-of-care ultrasonography (POCUS) is performed by a treating clinician at the patient's bedside, provides a acquisition, interpretation, and immediate clinical integration based on ultrasonographic imaging. The use of POCUS is not limited to one specialty, protocol, or organ system. POCUS provides the treating clinician with real-time diagnostic and monitoring information. Visual rounds based on multiorgan POCUS act as an initiative to improve clinical practice in the Intensive Care Unit and are urgently needed as part of routine clinical practice.

Number of attempts required by emergency physicians to achieve competency in diaphragmatic ultrasound imaging

PURPOSE

This research aimed to determine the number of attempts that emergency physicians need to become proficient in undertaking diaphragmatic ultrasound imaging.

METHODS

A prospective observational study was conducted at the emergency department (ED) of a tertiary-care university hospital. Sixteen emergency physicians were each required to obtain a set of images of the right hemidiaphragm of five dyspneic patients using both diaphragmatic excursion and thickness techniques. The images were subsequently reviewed by a specialist using American College of Emergency Physician guidelines. If the evaluations of a physician did not reach the expected standard, the physician was to be given feedback and requested to collect images from another five patients. The process was to be repeated until such time as the images obtained by the physician were deemed to be up to standard.

RESULTS

Eighty patients, twelve emergency medicine residents, and four attending physicians were enrolled. Following a didactic session on diaphragmatic ultrasound imaging and its interpretation, practicing on five patients proved sufficient to achieve an adequate level of competency in conducting diaphragmatic ultrasound examinations.

CONCLUSION

Practicing on five patients is sufficient for emergency physicians to achieve an adequate level of competency in conducting right-sided diaphragmatic ultrasound examinations.

Predictive Value of Diaphragmatic Ultrasonography for the Weaning Outcome in Mechanically Ventilated Children Aged 1-3 Years

BACKGROUND

There are estimated 20% of mechanically ventilated patients having difficulty in weaning from the ventilators, and the weaning process accounts for 40% of the whole ventilation time. Reliable tools are urgently needed to estimate the weaning outcome. Diaphragmatic ultrasonography, as a relatively good predictive method for the adults, was measured in this study, assessing the value of each indicator of diaphragmatic ultrasonography to predict the outcomes of ventilator weaning from mechanically ventilated children of 1-3 years old.

METHODS

Between November 2018 and November 2019, children who were mechanically ventilated and ready for weaning in the pediatric intensive care unit (PICU) were enrolled in the study. Diaphragmatic ultrasonography was performed to the children to measure the right diaphragm excursion (DE), contraction velocity, thickness, and diaphragm thickening fraction (DTF), which were recorded followed by spontaneous breathing trial (SBT). The receiver operator characteristic (ROC) curves were also used to assess the value of each indicator to predict the weaning outcome.

RESULTS

During this study period, a total of 72 children were enrolled, and of them, 56 children passed the weaning process, while 16 children failed. There were significant differences in DE, contraction velocity, thickness, and DTF parameters between the weaning success group and the failure group. The areas under the ROC curves (AUC) and the optimal threshold of the above indicators were as follows: 0.72 and 8.08 mm for DE, 0.71 and 26.1% for right DTF (DTF^R), 0.71 and 20.7% for left DTF (DTF^L), 0.78 and 14.8% for minimum DTF (DTF^MIN), 0.79 and 26.1% for maximum DTF (DTF^MAX), 0.71 and 1.24 mm for maximum diaphragm thickness at the end of inspiration (Dtei^MAX), and 0.65 and 10.0 mm/s for contraction velocity.

CONCLUSION

Diaphragmatic ultrasonography is feasible in guiding ventilator weaning, and the indicators of DE, DTF, and Dtei^MAX guide the weaning more accurately. Among them, DTF may act as a more reliable predictor of weaning by avoiding the influence of diaphragm development in children.

Diaphragm Ultrasound: A Valuable Predictor of the Outcome of Extubation. An Observational Pilot Study in Covid-19 Related ARDS

Introduction

Because both early and delayed weaning are associated with increased mortality, longer stay in the ICU and higher economic costs, performing extubation once the patient can cope with the respiratory load is completely recommended. Ultrasound Sonography (US) is an available bedside tool that allows a rapid assessment and visualization of the different structures involved in spontaneous breath. M-mode ultrasonography can be useful for the assessment of diaphragm kinetics, providing valuable information about diaphragm disfunction.

Aim of the Study

The aim of this study is to find a correlation between the value of the acceleration of the diaphragm detected with the US M-mode and the outcome of the weaning.

Materials and Methods

We have enrolled 19 patients admitted in our ICU. Each patient underwent the trial with the ultrasound M-mode to assess the acceleration of the diaphragm during the contraction. We have analyzed the results relating them to the outcome of the weaning.

Results

While 11 of our patients have had a successful weaning, 8 have failed it, and we can see that the outcome is associated to the values of acceleration.

Discussion

Our study has demonstrated that an assessment of the diaphragm function using US could represent a usable and effective technique as the acceleration is related to the force generated by the diaphragm contraction.

Conclusions

In conclusion, the acceleration could be a useful parameter to consider when it comes to the prediction of the outcome of the weaning process.

Diaphragmatic excursion is correlated with the improvement in exercise tolerance after pulmonary rehabilitation in patients with chronic obstructive pulmonary disease

BACKGROUND

In patients with chronic obstructive pulmonary disease (COPD), the maximum level of diaphragm excursion (DEmax) is correlated with dynamic lung hyperinflation and exercise tolerance. This study aimed to elucidate the utility of DEmax to predict the improvement in exercise tolerance after pulmonary rehabilitation (PR) in patients with COPD.

METHODS

This was a prospective cohort study. Of the 62 patients with stable COPD who participated in the outpatient PR programme from April 2018 to February 2021, 50 completed the programme. Six-minute walk distance (6MWD) was performed to evaluate exercise tolerance, and ultrasonography was performed to measure DEmax. Responders to PR in exercise capacity were defined as patients who demonstrated an increase of > 30 m in 6MWD. The receiver operating characteristic (ROC) curve was used to determine the cut-off point of DEmax to predict responses to PR.

RESULTS

Baseline levels of forced expiratory volume in 1 s, 6MWD, maximum inspiratory pressure, DEmax and quadriceps muscle strength were significantly higher, and peak dyspnoea of modified Borg (mBorg) scale score was lower in responders (n = 30) than in non-responders (n = 20) to PR (p < 0.01). In multivariate analysis, DEmax was significantly correlated with an increase of > 30 m in 6MWD. The area under the ROC curve of DEmax to predict responders was 0.915, with a sensitivity and specificity of 83% and 95%, respectively, at a cut-off value of 44.9 mm of DEmax.

CONCLUSION

DEmax could adequately predict the improvement in exercise tolerance after PR in patients with COPD.

Overall diagnostic accuracy of different MR imaging sequences for detection of dysplastic nodules: a systematic review and meta-analysis

OBJECTIVE

To assess the overall diagnostic accuracy of different MR imaging sequences in the detection of the dysplastic nodule (DN).

METHODS

PubMed, Cochrane Library, and Web of Science were systematically searched. Study selection and data extraction were conducted by two authors independently. Quality assessment of diagnostic accuracy studies (QUADAS) 2 in RevMan software was used to score the included studies and assess their methodological quality. A random-effects model was used for statistical pooling by Meta-Disc. Subgroup analysis and sensitivity analysis were used to explore potential sources of heterogeneity.

RESULTS

Fourteen studies (335 DN lesions in total) were included in our meta-analysis. The area under the curve (AUC) of summary receiver operating characteristic (SROC) of T₂WI was 0.87. Pooled sensitivity, specificity, positive likelihood ratio (PLR), and negative likelihood ratio (NLR) of DWI were 0.81 (95%CI, 0.73-0.87), 0.90 (95%CI, 0.86-0.93), 7.04 (95%CI, 4.49-11.04), and 0.24 (95%CI, 0.17-0.33) respectively. In the arterial phase, pooled sensitivity, specificity, PLR, and NLR were 0.89 (0.84-0.93), 0.75 (0.72-0.79), 3.72 (2.51-5.51), and 0.17 (0.12-0.25), respectively. Pooled sensitivity, specificity, PLR, and NLR of the delayed phase were 0.78 (0.72-0.83), 0.60 (0.55-0.65), 2.19 (1.55-3.10), and 0.36 (0.23-0.55) separately. Pooled sensitivity, specificity, PLR, and NLR of the hepatobiliary phase were 0.77 (0.71-0.82), 0.92 (0.89-0.94), 8.74 (5.91-12.92), and 0.24 (0.14-0.41) respectively. Pooled sensitivity, specificity, and PLR were higher on DWI and hepatobiliary phase in diagnosing LGDN than HGDN.

CONCLUSION

MR sequences, particularly DWI, arterial phase, and hepatobiliary phase imaging demonstrate high diagnostic accuracy for DN.

KEY POINTS

• MRI has dramatically improved the detection and accurate diagnosis of DNs and their differentiation from hepatocellular carcinoma. • Overall diagnostic accuracy of different MRI sequences in the detection of DN has not been studied before. • Our meta-analysis demonstrates that MRI achieves a high diagnostic value for DN, especially when using DWI, arterial phase imaging, and hepatobiliary phase imaging.

Point of care diaphragm ultrasound in acute bronchiolitis: A measurable tool to predict the clinical, sonographic severity of the disease, and outcomes

BACKGROUND

The aim of this study was to evaluate diaphragmatic parameters in bronchiolitis patients and identify correlations between clinical and sonographic severity scores and outcomes to develop a more objective and useful tool in the emergency department.

METHODS

Children aged between 1 and 24 months and diagnosed with acute bronchiolitis were included in the study. The Modified Respiratory Distress Assessment Instrument (mRDAI) score was used to quantify the clinical severity of the disease. Lung ultrasound was performed and a bronchiolitis ultrasound score (BUS) was calculated. Diaphragm ultrasound was then performed and diaphragm thickness at the end of inspiration and expiration, thickening fraction, diaphragm excursion (EXC), inspiratory slope (IS), expiratory slope (ES), and total duration time of the respiratory cycle were measured.

RESULTS

There were 104 patients evaluated in this study. The mRDAI score and BUS had a significant positive correlation. There was a positive correlation between IS and respiratory rate at admission. As the clinical score increased, IS, ES, and EXC measurements rose and they were positively correlated. Values of IS, ES, and EXC were higher in the moderate-severe group than the mild group for both mRDAI and BUS scores. Inspiratory slope values were correlated with the length of stay in the hospital.

CONCLUSION

Values of IS and ES were correlated with clinical and sonographic severity scores. Moreover, IS was a good predictor of outcome. Diaphragm ultrasound appears to be an objective and useful tool to help the physician make decisions regarding the evaluation and management of bronchiolitis.

Bedside noninvasive monitoring of mechanically ventilated patients

PURPOSE OF REVIEW

Among noninvasive lung imaging techniques that can be employed at the bedside electrical impedance tomography (EIT) and lung ultrasound (LUS) can provide dynamic, repeatable data on the distribution regional lung ventilation and response to therapeutic manoeuvres.In this review, we will provide an overview on the rationale, basic functioning and most common applications of EIT and Point of Care Ultrasound (PoCUS, mainly but not limited to LUS) in the management of mechanically ventilated patients.

RECENT FINDINGS

The use of EIT in clinical practice is supported by several studies demonstrating good correlation between impedance tomography data and other validated methods of assessing lung aeration during mechanical ventilation. Similarly, LUS also correlates with chest computed tomography in assessing lung aeration, its changes and several pathological conditions, with superiority over other techniques. Other PoCUS applications have shown to effectively complement the LUS ultrasound assessment of the mechanically ventilated patient.

SUMMARY

Bedside techniques - such as EIT and PoCUS - are becoming standards of the care for mechanically ventilated patients to monitor the changes in lung aeration, ventilation and perfusion in response to treatment and to assess weaning from mechanical ventilation.

Respiratory muscle imaging by ultrasound and MRI in neuromuscular disorders

Respiratory muscle weakness is common in neuromuscular disorders and leads to significant respiratory difficulties. Therefore, reliable and easy assessment of respiratory muscle structure and function in neuromuscular disorders is crucial. In the last decade, ultrasound and MRI emerged as promising imaging techniques to assess respiratory muscle structure and function. Respiratory muscle imaging directly measures the respiratory muscles and, in contrast to pulmonary function testing, is independent of patient effort. This makes respiratory muscle imaging suitable to use as tool in clinical respiratory management and as outcome parameter in upcoming drug trials for neuromuscular disorders, particularly in children. In this narrative review, we discuss the latest studies and technological developments in imaging of the respiratory muscles by US and MR, and its clinical application and limitations. We aim to increase understanding of respiratory muscle imaging and facilitate its use as outcome measure in daily practice and clinical trials.

Machine learning for the prediction of successful extubation among patients with mechanical ventilation in the intensive care unit: A retrospective observational study

BACKGROUND

Ventilator weaning protocols are commonly implemented for patients receiving mechanical ventilation. However, the rate of extubation failure remains high despite the protocols. This study investigated the usefulness and accuracy of ventilator weaning through machine learning to predict successful extubation.

METHODS

We retrospectively evaluated the data of patients who underwent intubation for respiratory failure and received mechanical ventilation in the intensive care unit (ICU). Data on 57 factors including patient demographics, vital signs, laboratory data, and data from ventilator were extracted. Extubation failure was defined as re-intubation within 72 hours of extubation. For supervised learning, the data were labeled requirement of intubation or not. We used three learning algorithms (Random Forest, XGBoost, and LightGBM) to predict successful extubation. We also analyzed important features and evaluated the area under curve (AUC) and prediction metrics.

RESULTS

Overall, 13 of the 117 included patients required re-intubation. LightGBM had the highest AUC (0.950), followed by XGBoost (0.946) and Random Forest (0.930). The accuracy, precision, and recall performance were 0.897, 0.910, and 0.909, for Random Forest; 0.910, 0.912, and 0.931 for XGBoost; and 0.927, 0.915, and 0.960 for LightGBM, respectively. The most important feature was the duration of mechanical ventilation followed by the fraction of inspired oxygen, positive end-expiratory pressure, maximum and mean airway pressures, and Glasgow Coma Scale.

CONCLUSIONS

Machine learning could predict successful extubation among patients on mechanical ventilation in the ICU. LightGBM has the highest overall performance. The duration of mechanical ventilation was the most important feature in all models.

European Respiratory Society statement on thoracic ultrasound

Thoracic ultrasound is increasingly considered to be an essential tool for the pulmonologist. It is used in diverse clinical scenarios, including as an adjunct to clinical decision making for diagnosis, a real-time guide to procedures and a predictor or measurement of treatment response. The aim of this European Respiratory Society task force was to produce a statement on thoracic ultrasound for pulmonologists using thoracic ultrasound within the field of respiratory medicine. The multidisciplinary panel performed a review of the literature, addressing major areas of thoracic ultrasound practice and application. The selected major areas include equipment and technique, assessment of the chest wall, parietal pleura, pleural effusion, pneumothorax, interstitial syndrome, lung consolidation, diaphragm assessment, intervention guidance, training and the patient perspective. Despite the growing evidence supporting the use of thoracic ultrasound, the published literature still contains a paucity of data in some important fields. Key research questions for each of the major areas were identified, which serve to facilitate future multicentre collaborations and research to further consolidate an evidence-based use of thoracic ultrasound, for the benefit of the many patients being exposed to clinicians using thoracic ultrasound.

Sonographic evaluation of diaphragmatic thickness and excursion as a predictor for successful extubation in mechanically ventilated preterm infants

Sonographic assessment of diaphragmatic thickness and excursion has been found to be an accurate tool in predicting successful extubation of adult patients from invasive mechanical ventilation. We aimed to evaluate the accuracy of sonographic assessment of diaphragmatic thickness and excursion in predicting successful extubation of preterm infants from invasive conventional mechanical ventilation. Preterm infants less than 32 weeks gestation who required invasive conventional mechanical ventilation were evaluated by diaphragmatic sonography within 1 h of their planned extubation. Infants were classified into successful or failed extubation groups based on their ability to stay off invasive mechanical ventilation for 72 h after extubation. Inspiratory and expiratory thickness plus excursion of the right and left hemidiaphragm as well as diaphragmatic thickening fraction (DTF) measures were compared between groups. We included 43 eligible infants, of whom 34 infants succeeded and 9 infants failed extubation. Infants in the successful extubation group had a significantly higher expiratory thickness of the right and left hemidiaphragm, excursion of the right and left hemidiaphragm, inspiratory thickness of the left hemidiaphragm, and DTF of the left hemidiaphragm compared with infants who failed extubation. The receiver-operating characteristic curves showed that excursion of the right and left hemidiaphragm has the highest significant accuracy in predicting successful extubation of preterm infants among all diaphragmatic parameters (AUC is 0.98 and 0.96, respectively; p value < 0.001 for both).Conclusion: We conclude that diaphragmatic excursion is a useful indicator for successful extubation of preterm infants from mechanical ventilation. What is Known: • Invasive mechanical ventilation induces ventilator induced diaphragmatic dysfunction (VIDD) particularly when used for long time. • Assessment of diaphragmatic dimensions and functional activity has been a valuable tool in predicting successful extubation of adult patients from invasive mechanical ventilation. What is New: • Sonographic assessment of diaphragmatic dimensions can be used to predict successful extubation of preterm infants from mechanical ventilation. • Sonographic assessment of diaphragmatic excursion shows the highest sensitivity and specificity in predicting successful extubation of preterm infants.

Multi-organ point-of-care ultrasound for COVID-19 (PoCUS4COVID): international expert consensus

COVID-19 has caused great devastation in the past year. Multi-organ point-of-care ultrasound (PoCUS) including lung ultrasound (LUS) and focused cardiac ultrasound (FoCUS) as a clinical adjunct has played a significant role in triaging, diagnosis and medical management of COVID-19 patients. The expert panel from 27 countries and 6 continents with considerable experience of direct application of PoCUS on COVID-19 patients presents evidence-based consensus using GRADE methodology for the quality of evidence and an expedited, modified-Delphi process for the strength of expert consensus. The use of ultrasound is suggested in many clinical situations related to respiratory, cardiovascular and thromboembolic aspects of COVID-19, comparing well with other imaging modalities. The limitations due to insufficient data are highlighted as opportunities for future research.

Diaphragmatic ultrasound: a review of its methodological aspects and clinical uses

The diaphragm is the main muscle of respiration, acting continuously and uninterruptedly to sustain the task of breathing. Diaphragmatic dysfunction can occur secondary to numerous pathological conditions and is usually underdiagnosed in clinical practice because of its nonspecific presentation. Although several techniques have been used in evaluating diaphragmatic function, the diagnosis of diaphragmatic dysfunction is still problematic. Diaphragmatic ultrasound has gained importance because of its many advantages, including the fact that it is noninvasive, does not expose patients to radiation, is widely available, provides immediate results, is highly accurate, and is repeatable at the bedside. Various authors have described ultrasound techniques to assess diaphragmatic excursion and diaphragm thickening in the zone of apposition. Recent studies have proposed standardization of the methods. This article reviews the usefulness of ultrasound for the evaluation of diaphragmatic function, addressing the details of the technique, the main findings, and the clinical applications.

Diaphragm Function Assessment During Spontaneous Breathing Trial in Patients with Neuromuscular Diseases

Introduction

The optimal time to discontinue patients from mechanical ventilation is critical as premature discontinuation as well as delayed weaning can result in complications. The literature on diaphragm function assessment during the weaning process in the intriguing subpopulation of critically ill neuromuscular disease patients is lacking.

Methods

Patients with neuromuscular diseases, on mechanical ventilation for more than 7 days, and who were ready for weaning were studied. During multiple T-piece trials over days, diaphragm function using ultrasound and diaphragm electrical activity (Edi peaks using NAVA catheter) was measured every 30 min till a successful 2 h weaning.

Results

A total of 18 patients were screened for eligibility over 5-month period and eight patients fulfilled the inclusion criteria. Sixty-three data points in these 8 subjects were available for analysis. A successful breathing trial was predicted by Edi reduction (1.22 μV for every 30 min increase in weaning duration; 0.69 μV for every day of weaning) and increase in diaphragm excursion (2.81 mm for every 30 min increase in weaning duration; 2.18 mm for every day of weaning).

Conclusion

The Edi and diaphragm excursion changes can be used as additional objective tools in the decision-making of the weaning trials in neuromuscular disease.

Electronic supplementary material

The online version of this article (10.1007/s12028-020-01141-9) contains supplementary material, which is available to authorized users.

Extubating to Noninvasive Ventilation: Noninvasive Ventilation from Intensive Care Unit to Home

Weaning to noninvasive ventilation in intensive care unit and bridging the patients to home with respiratory support is evolving as the technology of noninvasive ventilation is improving. In patients with chronic obstructive pulmonary disease exacerbation, timing of initiation of noninvasive ventilation is the key, as persistently hypercapnic patients show benefits. High-intensity pressure support seems to do better in comparison to low-intensity pressure support. In patients with obesity and hypercapnia, obesity hypoventilation cannot be ruled out especially in an inpatient setting, and it is crucial that these patients are discharged with noninvasive ventilation.

Use of ultrasonography in COVID-19: Probing for success

The ongoing pandemic of COVID-19 has put an immense strain on healthcare facilities around the world. Unique challenges are being faced in the adequate management of rapidly increasing number of cases while ensuring adequate healthcare providers apostrophe safety. Issues related to the difficulty of examination while wearing personal protective equipment, need for objectivity in triage and testing of patients, and evidence-based management of the critically ill has resulted in reliance on longitudinal radiological assessment. There are a number of portability, disinfection and radiation exposure related problems with the use of X-rays and computerized tomography (CT). Point of care ultrasonography provides a pragmatic, safe, and repeatable approach for addressing the pertinent clinical questions that have traditionally relied on X-rays and CT scans. Here, we summarize the use ultrasound assessment can play in the triage, identification, and subsequent management of patients with COVID-19.

Use of Ultrasound to Determine Changes in Diaphragm Mechanics During A Spontaneous Breathing Trial

OBJECTIVE

Assess change in ultrasound measures of diaphragm mechanics over the course of a 30-minute spontaneous breathing trial (SBT).

DESIGN

Prospective observational study.

SETTING

Single intensive care unit (Logan Hospital, Queensland, Australia), patients recruited from August 2016 to April 2018.

PARTICIPANTS

Eligible patients were over the age of 18 years, ventilated for >24 hours, and planned to undergo an SBT. In total, 129 patients were screened.

MAIN OUTCOME MEASURES

Ultrasound measures taken at 5 and 30 minutes during SBT: diaphragmatic excursion (DE), diaphragmatic thickening fraction (DTF), and diaphragmatic contraction speed (DCS). Diaphragmatic rapid shallow breathing index (DRSBI) was calculated using DE/respiratory rate. The presence of diaphragmatic dysfunction (DD) was also determined using DTF < 30%, DE < 11 mm, or DRSBI > 1.6.

RESULTS

Eighteen patients had ultrasound measures during an SBT. Four were unable to have DTF visualized. There was no significant change in DTF (n = 14, 32.41 ± 32.21 vs 23.19 ± 17.42, P = .33) or DE (n = 18, 1.72 ± 0.63 vs 1.66 ± 0.59, P = .63) over time. Diaphragmatic contraction speed increased over time (n = 18, 2.21 ± 1.25 vs 2.67 ± 1.61, P = .007). Diaphragmatic rapid shallow breathing index worsened over time (n = 18, 1.65 ± 1.02 vs 2.08 ± 1.51, P = .03). There was no significant change in the presence of DD. Diaphragmatic dysfunction by DTF 8/14 versus 10/14, by DE 4/18 versus 3/18, and by DRSBI 7/18 versus 9/18. No patients failed SBT and one patient failed extubation.

CONCLUSIONS

Diaphragmatic mechanics may change over the course of an SBT. Further research is required to determine the clinical implications of these changes and the optimal timing of diaphragmatic ultrasound to predict weaning outcome. Diaphragmatic ultrasound may be less feasible than the published data suggest.

Diagnostic thoracic ultrasound imaging - An exploration of respiratory physiotherapists' interest and use in clinical practice: A national survey

INTRODUCTION

Physiotherapists are learning to perform diagnostic thoracic ultrasound but it is currently unknown how they are learning, how they are using thoracic ultrasound in their practice, or any factors affecting the implementation of thoracic ultrasound into practice. The aim of this survey was to explore the use of thoracic ultrasound by physiotherapists. This information could be used to aid training and implementation strategies to assist physiotherapists to integrate thoracic ultrasound safely into their practice.

METHODS

A questionnaire comprising of open/closed questions was distributed to respiratory physiotherapist. Distribution was at three national study days and via a specialist newsletter containing a link to a SurveyMonkey™ questionnaire.

RESULTS

A total of 133 questionnaires were returned with 31 reported that they used thoracic ultrasound imaging and 101 reporting they did not. The most common roles of thoracic ultrasound in practice were to: enhance the ability to differentially diagnose respiratory pathologies, aid respiratory assessment and support clinical reasoning. Of the 133 respondents, 58 reported that they had undertaken training in thoracic ultrasound imaging and 75 had not. The most common factors identified regarding thoracic ultrasound implementation were team support, ultrasound machine availability/cost, time pressures and mentor availability.

DISCUSSION

This survey has provided an understanding of thoracic ultrasound practice amongst respiratory physiotherapists in the UK. The survey results demonstrated the barriers that inhibit current practice and highlighted the importance of mentor support. There was a good understanding by all respondents regarding the clinical application of thoracic ultrasound. These findings are being used to develop professional guidance and ensure safe practice of thoracic ultrasound.

[Usefulness of diaphragmatic ultrasound in predicting extubation success]

OBJECTIVE

To evaluate the diagnostic accuracy of diaphragmatic ultrasound in predicting extubation success.

DESIGN

A diagnostic accuracy study was carried out.

SCOPE

Intensive Care Unit of an Academic hospital in the city of Bogotá (Colombia).

PATIENTS OR PARTICIPANTS

A consecutive sample of patients >18 years of age subjected to invasive mechanical ventilation for >48h.

INTERVENTIONS

Diaphragmatic ultrasound evaluation at the end of spontaneous ventilation testing.

MAIN VARIABLES OF INTEREST

Diaphragmatic excursion (DE, cm), inspiration time (TPIA_dia, s), diaphragm contraction speed (DE/TPIA_dia, cm/s) and total time (Ttot, s) were evaluated, together with thickening fraction (TF_di, %).

RESULTS

A total of 84 patients were included, 79.8% (n=67) with successful extubation and 20.2% (n=17) with failed extubation. The variable with the best discriminatory capacity in predicting extubation success was diaphragm contraction speed, with AUC-ROC 0.70 (p=0.008).

CONCLUSIONS

Diaphragm contraction speed exhibited acceptable discriminatory capacity. Ultrasound could be part of a multifactorial approach in the extubation process.

Ventilator-induced diaphragm dysfunction: translational mechanisms lead to therapeutical alternatives in the critically ill

Mechanical ventilation [MV] is a life-saving technique delivered to critically ill patients incapable of adequately ventilating and/or oxygenating due to respiratory or other disease processes. This necessarily invasive support however could potentially result in important iatrogenic complications. Even brief periods of MV may result in diaphragm weakness [i.e., ventilator-induced diaphragm dysfunction [VIDD]], which may be associated with difficulty weaning from the ventilator as well as mortality. This suggests that VIDD could potentially have a major impact on clinical practice through worse clinical outcomes and healthcare resource use. Recent translational investigations have identified that VIDD is mainly characterized by alterations resulting in a major decline of diaphragmatic contractile force together with atrophy of diaphragm muscle fibers. However, the signaling mechanisms responsible for VIDD have not been fully established. In this paper, we summarize the current understanding of the pathophysiological pathways underlying VIDD and highlight the diagnostic approach, as well as novel and experimental therapeutic options.