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Background: Studies conducted in interstitial lung disease (ILD) patients to assess diaphragmatic excursion and thickening fraction suggest a weak to strong correlation with pulmonary function parameters. However, diaphragmatic excursion velocity, a novel imaging marker, has not been correlated with pulmonary function and high-resolution computed tomography (HRCT) fibrosis score in ILD patients previously. Methods: We conducted a cross-sectional analytical study in 40 ILD patients during quiet (QB) and deep breathing (DB) to measure diaphragmatic thickening, excursion and excursion velocity using transthoracic ultrasound and correlated them with pulmonary function parameters and HRCT fibrosis score. Results: Most diaphragm parameters in DB correlated more strongly with lung function parameters compared to quiet breathing. Right diaphragmatic excursion, during QB and DB, showed positive correlations with forced vital capacity (FVC) z-score (r = 0.591, 0.676) and diffusion capacity of the lung for carbon monoxide (DLCO) z-score (r = 0.437, 0.438), and negative correlations with HRCT fibrosis score (r = -0.439, -0.425), respectively. In addition, right diaphragmatic velocity exhibited positive correlations with FVC z-score (r = 0.388, 0.667) and DLCO z-score (r = 0.139, 0.412), and negative correlations with HRCT fibrosis score (r = -0.454, -0.445). Right diaphragm thickening fraction showed positive correlations with FVC z-score (r = 0.330, 0.460) and DLCO z-score (r = 0.400, 0.426), and negative correlations with HRCT fibrosis score (r = -0.199, -0.237). Similarly, right diaphragmatic thickness indicated positive correlations with FVC z-score (r = 0.526, 0.614) and DLCO z-score (r = 0.298, 0.298), and negative correlations with HRCT fibrosis score (r = -0.398, -0.401). Conclusion: Diaphragmatic excursion velocity during DB showed a weak to moderate correlation with pulmonary function parameters and HRCT fibrosis score and may be utilized as a surrogate marker in ILD patients unable to perform pulmonary function tests or undergo sequential HRCT thorax in follow-up. [ABSTRACT FROM AUTHOR]

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 among 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

BackgroundUltrasound has demonstrated its interest in the analysis of diaphragm function in patients with respiratory failure. The criteria used to diagnose hemidiaphragm paralysis are not well defined.MethodsThe aim of this observational retrospective study was to describe the ultrasound findings in 103 patients with diaphragm paralysis, previously diagnosed by conventional methods after various circumstances such as trauma or surgery. The ultrasound study included the recording of excursions of both diaphragmatic domes and the measurement of inspiratory thickening.ResultsOn paralyzed hemidiaphragm, thickening was less than 20% in all patients during deep inspiration. Thinning was recorded in 53% of cases. In some cases, the recording of the thickening could be difficult. The study of motion during voluntary sniffing reported a paradoxical excursion in all but one patient. During quiet breathing, an absence of movement or a paradoxical displacement was observed. During deep inspiration, a paradoxical motion at the beginning of inspiration followed by a reestablishment of movement in the cranio-caudal direction was seen in 82% of cases. In some patients, there was a lack of movement followed, after an average delay of 0.4 s, by a cranio-caudal excursion. Finally, in 4 patients no displacement was recorded. Evidence of hyperactivity (increased inspiratory thickening and excursion) of contralateral non-paralyzed hemidiaphragm was observed.ConclusionTo accurately detect hemidiaphragm paralysis, it would be interesting to combine the ultrasound study of diaphragm excursion and thickening. The different profiles reported by our study must be known to avoid misinterpretation.

Beclomethasone dipropionate/formoterol fumarate/glycopyrronium (BDP/FF/G) single inhaler extrafine triple therapy is effective for the treatment of uncontrolled asthma. Nevertheless, there is a lack of data about the use of diaphragmatic ultrasonography to monitor adult asthmatics while they are receiving inhaled treatment. We took into consideration a 78-year-old woman complaining of asthma, treated with inhaled corticosteroid/long-acting β2-adrenergic agonist (ICS/LABA), characterized by an asthma control questionnaire-5 (ACQ-5) score and a lung function test suggestive of uncontrolled asthma. Moreover, a diaphragmatic ultrasound showed signs of high diaphragm workload. Because of these findings, we proposed to our patient a shift toward triple inhaled therapy with BDP/FF/G, and she underwent a second evaluation after 7 days of treatment. Improvements in the diaphragmatic ultrasound parameters, lung function test, and ACQ-5 score were found. In particular, we detected a reduction of thickening fraction (TF), and a normalization of the other diaphragmatic measures, indicative of a decrease in diaphragmatic workload. To our knowledge, this is the first literature report showing concomitant improvements of both lung function tests and diaphragmatic ultrasonography parameters, observed in an adult patient with uncontrolled asthma after short-term treatment with the single inhaler triple therapy BDP/FF/G.

Summary: Background: Diaphragmatic function can be affected in many diseases and disorders. Although systemic sclerosis (SSc) is a serious connective tissue disease that affects not only the skin but also the pulmonary and musculoskeletal systems, there is insufficient information about diaphragm function. Aims: To compare the diaphragmatic parameters by ultrasonography (USG) in patients with SSc and healthy individuals and examine the relationship between these parameters and clinical features in patients with SSc. Methods: This study included 13 patients with SSc and 15 healthy individuals. Muscle thickness (in deep inspiration Tins and at the end of calm expiration Texp), changes in thickness (∆T), and thickening fraction at deep breathing were evaluated by USG. Skin thickness, pulmonary function tests, respiratory muscle strength, and the perception of dyspnea were measured as clinical features. Results: The results of Texp, Tins, and ∆T were similar in both groups (p > 0.05), albeit patients in the SSc group had less thickening fraction compared to the control group (79.9 ± 36.7 cm and 103.8 ± 20.6 cm, respectively, p < 0.05). The Tins, ∆T, and thickening fraction of the diaphragm were associated with skin thickness, pulmonary function test parameters, and respiratory muscle strength (p < 0.05). Besides, there was significant correlation between muscle thickening fraction and perception of dyspnea (p < 0.05). Conclusion: These results confirm that diaphragm thickness and contractility can be affected in patients with SSc. Therefore, ultrasonographic evaluation of the diaphragm can play a complementary role to pulmonary function test and respiratory muscle strength measurement in the diagnosis and follow-up of patients with SSc. [ABSTRACT FROM AUTHOR]

Diaphragmatic thickness (Tdi) and diaphragm thickening fraction (dTF) are widely used parameters in ultrasound studies of the diaphragm in mechanically ventilated children, but normal values for healthy children are scarce. We determined reference values of Tdi and dTF using ultrasound in healthy children aged 0–8 years old and assessed their reproducibility. In a prospective, observational cohort, Tdi and dTF were measured on ultrasound images across four age groups comprising at least 30 children per group: group 1 (0–6 months), group 2 (7 months-1 year), group 3 (2–4 years) and group 4 (5–8 years). Ultrasound images of 137 healthy children were included. Mean Tdi at inspiration was 2.07 (SD 0.40), 2.09 (SD 0.40), 1.69 (SD 0.30) and 1.72 (SD 0.30) mm for groups 1, 2, 3 and 4, respectively. Mean Tdi at expiration was 1.64 (SD 0.30), 1.67 (SD 0.30), 1.38 (SD 0.20) and 1.42 (SD 0.20) mm for groups 1, 2, 3 and 4, respectively. Mean Tdi at inspiration and mean Tdi at expiration for groups 1 and 2 were significantly greater than those for groups 3 and 4 (both p < 0.001). Mean dTF was 25.4% (SD 10.4), 25.2% (SD 8.3), 22.8% (SD 10.9) and 21.3% (SD 7.1) for group 1, 2, 3 and 4, respectively. The intraclass correlation coefficients (ICC) representing the level of inter-rater reliability between two examiners performing the ultrasounds was 0.996 (95% CI 0.982–0.999). ICC of the inter-rater reliability between the raters in 11 paired assessments was 0.989 (95% CI 0.973–0.995). Conclusion: Ultrasound measurements of Tdi and dTF were highly reproducible in healthy children aged 0–8 years. Trial registration: ClinicalTrials.gov identifier (NCT number): NCT04589910. What is Known: • Diaphragmatic thickness and diaphragm thickening fraction are widely used parameters in ultrasound studies of the diaphragm in mechanically ventilated children, but normal values for healthy children to compare these with are scarce. What is New: • We determined normal values of diaphragmatic thickness and diaphragm thickening fraction using ultrasound in 137 healthy children aged 0–8 years old. The diaphragmatic thickness of infants up to 1 year old was significantly greater than that of children from 2 to 8 years old. Diaphragmatic thickness decreased with an increase in body surface area. These normal values in healthy children can be used to assess changes in respiratory muscle thickness in mechanically ventilated children. [ABSTRACT FROM AUTHOR]

BackgroundAlthough previous studies have determined limit values of normality for diaphragm excursion and thickening, it would be beneficial to determine the normal diaphragm motion-to-inspired volume ratio that integrates the activity of the diaphragm and the quality of the respiratory system.MethodsTo determine the normal values of selected ultrasound diaphragm motion-volume indices, subjects with normal pulmonary function testing were recruited. Ultrasound examination recorded diaphragm excursion on both sides during quiet breathing and deep inspiration. Diaphragm thickness was also measured. The inspired volumes of the corresponding cycles were systematically recorded using a spirometer. The indices were calculated using the ratio excursion, or percentage of thickening, divided by the corresponding breathing volume. From this corhort, normal values and limit values for normality were determined. These measurements were compared to those performed on the healthy side in patients with hemidiaphragm paralysis because an increase in hemidiaphragm activity has been previously demonstated in such circumstances.ResultsA total of 122 subjects (51 women, 71 men) with normal pulmonary function were included in the study. Statistical analysis revealed that the ratio of excursion, or percentage of thickening, to inspired volume ratio significantly differed between males and females. When the above-mentioned indices using excursion were normalized by body weight, no gender differences were found. The indices differed between normal respiratory function subjects and patients with hemidiaphragm paralysis (27 women, 41 men). On the paralyzed side, the average ratio of the excursion divided by the inspired volume was zero. On the healthy side, the indices using the excursion and the percentage of thickening during quiet breathing or deep inspiration were significantly increased comparedto patients with normal lung function. According to the logistic regression analysis, the most relevant indice appeared to be the ratio of the excursion measured during quiet breathing to the inspired volume.ConclusionThe normal values of the diaphragm motion-volume indices could be useful to estimate the performance of the respiratory system. Proposed indices appear suitable in a context of hyperactivity.

IntroductionIn mechanically ventilated adults, thickening fraction of diaphragm (dTF) measured by ultrasound is used to predict extubation success. Whether dTF can also predict extubation success in children is unclear.AimTo investigate the association between dTF and extubation success in children. Second, to assess diaphragm thickness during ventilation and the correlation between dTF, diaphragm thickness (Tdi), age and body surface.MethodProspective observational cohort study in children aged 0–18 years old with expected invasive ventilation for >48 h. Ultrasound was performed on day 1 after intubation (baseline), day 4, day 7, day 10, at pre-extubation, and within 24 h after extubation. Primary outcome was the association between dTF pre-extubation and extubation success. Secondary outcome measures were Tdi end-inspiratory and Tdi end-expiratory and atrophy defined as

Objectives: In critically ill, mechanically ventilated adults, diaphragmatic atrophy and reduced diaphragmatic thickening fraction (DTF) has been associated with poor extubation outcomes. Diaphragmatic ultrasound assessment in critically ill pediatric patients shows similar results, though studies are on‐going. We sought to explore the feasibility and utility of using DTF, obtained during a spontaneous breathing trial (SBT) in predicting weaning outcomes. Methods: We conducted a prospective, observational study in a single‐center tertiary noncardiac pediatric intensive care unit (PICU) in a children's hospital. Mechanically ventilated pediatric patients were included except for those with preexisting conditions of neuromuscular weakness, diaphragm paresis, or chronic respiratory failure requiring non‐invasive or invasive mechanical ventilation at baseline. A convenience sample of 38 patients were included in the study. Results: Weaning failure occurred in 10/38 (26%) instances with 9/38 (24%) occurring due to failed SBT and 1/38 (2%) due to failed extubation requiring reintubation. Median DTF was 24% (IQR: 12–33). DTF was significantly lower in instances of failed SBT, 12% compared to 27% (P <.01). The odds ratio (OR) of SBT failure utilizing: TF < 25% is 12 (CI: 1.33–108.0, Z‐score: 2.22, P =.027), TV <5 mL/kg was 10.4 (CI: 1.76–61.67, Z‐score: 2.58, P =.01), and combined TV <5 mL/kg and TF < 25% is 17.6 (CI: 1.19–259.61, Z‐score: 2.09, P =.04). Conclusions: Our preliminary study suggests that ultrasound measurements of diaphragm thickening fraction during spontaneous breaths in mechanically ventilated pediatric patients may be a useful addition in predicting weaning readiness. [ABSTRACT FROM AUTHOR]

Abstract Background The diaphragm muscle whose dysfunction may be very common in patients undergoing mechanical ventilation (Ferrari G, De Filippi G, Elia F, Panero F, Volpicelli G, Aprà F. Crit Ultrasound J 6:8, 2014). Aim: To evaluate real-time ultrasound in the evaluation of diaphragmatic thickening, thickening fraction, and/or excursion to predict extubation outcomes. We aimed to compare these parameters with other traditional weaning measures is a fundamental. Results Out of 80 included patients, 20 (25%) have failed extubation. Diaphragmatic thickening (DT), thickening fraction (DTF), and/or excursion (DE) were significantly higher in the successful group compared to those who failed extubation (p < 0.05). Cutoff values of diaphragmatic measures associated with successful extubation (during tidal breathing) were ≥ 17 mm for DE; ≥ 2.1 cm for DT inspiration; ≥ 15.5 mm for DT expiration, functional residual capacity (FRC); and ≥ 32.82% for DTF %, giving 68%, 95%, 62%, and 90% sensitivity, respectively, and 65%, 100%, 100%, and 75% specificity, respectively. Cutoff values of diaphragmatic parameters associated with successful extubation (during deep breathing) were > 28.5 mm DT Insp, total lung capacity (TLC); >22.5mm DT Exp (RV); >37 DTF %; and > 31 mm DE, giving 100%, 73%, 97%, and 75% sensitivity and 65%, 75%, 100%, and 55% specificity, respectively. Rapid shallow breathing index (RSBI) had 47% sensitivity but 90% specificity. Conclusion Ultrasound evaluation of diaphragmatic parameters could be a good predictor of weaning in patients who passed the T-tube.

BackgroundSARS-CoV-2 infection can impair diaphragm function at the acute phase but the frequency of diaphragm dysfunction after recovery from COVID-19 remains unknown.Materials and methodsThis study was carried out on patients reporting persistent respiratory symptoms 3–4 months after severe COVID-19 pneumonia. The included patients were selected from a medical consultation designed to screen for recovery after acute infection. Respiratory function was assessed by a pulmonary function test, and diaphragm function was studied by ultrasonography.ResultsIn total, 132 patients (85M, 47W) were recruited from the medical consultation. During the acute phase of the infection, the severity of the clinical status led to ICU admission for 58 patients (44%). Diaphragm dysfunction (DD) was detected by ultrasonography in 13 patients, two of whom suffered from hemidiaphragm paralysis. Patients with DD had more frequently muscle pain complaints and had a higher frequency of prior cardiothoracic or upper abdominal surgery than patients with normal diaphragm function. Pulmonary function testing revealed a significant decrease in lung volumes and DLCO and the dyspnea scores (mMRC and Borg10 scores) were significantly increased in patients with DD. Improvement in respiratory function was recorded in seven out of nine patients assessed 6 months after the first ultrasound examination.ConclusionAssessment of diaphragm function by ultrasonography after severe COVID-19 pneumonia revealed signs of dysfunction in 10% of our population. In some cases, ultrasound examination probably discovered an un-recognized pre-existing DD. COVID-19 nonetheless contributed to impairment of diaphragm function. Prolonged respiratory physiotherapy led to improvement in respiratory function in most patients.Clinical trial registration[www.cnil.fr], identifier [#PADS20-207].

Aim: This study aimed to sonographically examine the fraction of thickening in the respiratory muscles during the acute exacerbation of chronic obstructive pulmonary disease (COPD) and to determine its relationship with the clinical severity of the exacerbation. Methods: This prospective study looked at 159 people over the age of 50 who were diagnosed with COPD using the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria and were admitted to the hospital because they were having an acute COPD flare-up. Ultrasonography was used to measure how thick the parasternal intercostals, pectoralis major, and diaphragm muscles were in each patient. Results: Of the patients, 63 had mild, 63 had moderate, and 33 had severe exacerbations. Parasternal intercostal and pectoralis major muscle thickening fractions were significantly higher in moderate and severe exacerbations compared to mild exacerbations, while the diaphragm muscle thickening fraction was significantly lower (p

Background: Diagnosing diaphragm dysfunction in the absence of complete paralysis remains difficult. The aim of the present study was to assess the normal values of the thickness and the inspiratory thickening of both hemidiaphragms as measured by ultrasonography in healthy volunteers while in a seated position.Methods: Healthy volunteers with a normal pulmonary function test were recruited. The diaphragmatic thickness was measured on both sides at the zone of apposition of the diaphragm to the rib cage during quiet breathing at end-expiration, end-inspiration, and after maximal inspiration. The thickening ratio, the thickening fraction, and the thickness at end-inspiration divided by the thickness at deep breathing were determined. The mean values and the lower and upper limits of normal were determined for men and women.Results: 200 healthy volunteers (100 men and 100 women) were included in the study. The statistical analysis revealed that women had a thinner hemidiaphragm than men on both sides and at the various breathing times studied. The lower limit of normality of the diaphragm thickness measured at end-expiration was estimated to be 1.3 mm in men and 1.1 mm in women, on both sides. The thickening fraction did not differ significantly between men and women. In men, it ranged from 60 to 260% on the left side and from 57 to 200% on the right side. In women, it ranged from 58 to 264% on the left side and from 60 to 229% on the right side. The lower limits of normality of the thickening fraction were determined to be 40 and 39% in men and 39 and 48% in women for the right and left hemidiaphragms, respectively. The upper limit for normal of the mean of both sides of the ratio thickness at end-inspiration divided by the thickness at deep breathing was determined to be 0.78 in women and 0.79 in men.Conclusion: The normal values of thickness and the indexes of diaphragmatic function should help clinicians with detecting diaphragm atrophy and dysfunction.

Abstract Background The use of ultrasound to visualize the diaphragm is well established. Over the last 15 years, certain indices of diaphragm function, namely diaphragm thickness, thickening fraction and excursion have been established for mechanically ventilated patients to track changes in diaphragm size and function over time, to assess and diagnose diaphragmatic dysfunction, and to evaluate if these indices can predict successful liberation from mechanical ventilation. In the last 2 years, three meta-analyses and a systematic review have assessed the usability of diaphragmatic ultrasound to predict successful weaning. Since then, further data have been published on the topic. Conclusions The aim of this narrative review is to briefly describe the common methods of diaphragmatic function assessment using ultrasound techniques, before summarizing the major points raised by the recent reviews. A narrative summary of the most recent data will be presented, before concluding with a brief discussion of future research directions in this field.

Background: Ultrasound has demonstrated its interest in the analysis of diaphragm function in patients with respiratory failure. The criteria used to diagnose hemidiaphragm paralysis are not well defined., Methods: The aim of this observational retrospective study was to describe the ultrasound findings in 103 patients with diaphragm paralysis, previously diagnosed by conventional methods after various circumstances such as trauma or surgery. The ultrasound study included the recording of excursions of both diaphragmatic domes and the measurement of inspiratory thickening., Results: On paralyzed hemidiaphragm, thickening was less than 20% in all patients during deep inspiration. Thinning was recorded in 53% of cases. In some cases, the recording of the thickening could be difficult. The study of motion during voluntary sniffing reported a paradoxical excursion in all but one patient. During quiet breathing, an absence of movement or a paradoxical displacement was observed. During deep inspiration, a paradoxical motion at the beginning of inspiration followed by a reestablishment of movement in the cranio-caudal direction was seen in 82% of cases. In some patients, there was a lack of movement followed, after an average delay of 0.4 s, by a cranio-caudal excursion. Finally, in 4 patients no displacement was recorded. Evidence of hyperactivity (increased inspiratory thickening and excursion) of contralateral non-paralyzed hemidiaphragm was observed., Conclusion: To accurately detect hemidiaphragm paralysis, it would be interesting to combine the ultrasound study of diaphragm excursion and thickening. The different profiles reported by our study must be known to avoid misinterpretation., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Boussuges, Fourdrain, Leone, Brioude, Menard, Zieleskiewicz, Delliaux, Gouitaa, Dutau and Brégeon.)

Background:  Mechanical ventilation is a life-saving intervention for critically ill patients, but it can also lead to diaphragm atrophy, which may prolong the duration of mechanical ventilation and the length of stay in the intensive care unit. IntelliVent-ASV® (Hamilton Medical, Rhäzüns, Switzerland) is a new mode of ventilation that has been developed to reduce diaphragm atrophy by promoting spontaneous breathing efforts. In this study, we aimed to evaluate the effectiveness of IntelliVent-ASV® and pressure support-synchronized intermittent mandatory ventilation (PS-SIMV) mode in reducing diaphragm atrophy by measuring diaphragm thickness using ultrasound (US) imaging., Methods:  We enrolled 60 patients who required mechanical ventilation due to respiratory failure and were randomized into two groups: IntelliVent-ASV ®  and PS-SIMV. We measured the diaphragm thickness using US imaging at admission and on the seventh day of mechanical ventilation., Results: Our results showed that diaphragm thickness decreased significantly in the PS-SIMV group but remained unchanged in the IntelliVent-ASV ®  group. The difference in diaphragm thickness between the two groups was statistically significant on the seventh day of mechanical ventilation., Conclusions: IntelliVent-ASV ®  may reduce diaphragm atrophy by promoting spontaneous breathing efforts. Our study suggests that this new mode of ventilation may be a promising approach to preventing diaphragm atrophy in mechanically ventilated patients. Further studies using invasive measures of diaphragm function are warranted to confirm these findings., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2023, Alay et al.)

Background: Although previous studies have determined limit values of normality for diaphragm excursion and thickening, it would be beneficial to determine the normal diaphragm motion-to-inspired volume ratio that integrates the activity of the diaphragm and the quality of the respiratory system., Methods: To determine the normal values of selected ultrasound diaphragm motion-volume indices, subjects with normal pulmonary function testing were recruited. Ultrasound examination recorded diaphragm excursion on both sides during quiet breathing and deep inspiration. Diaphragm thickness was also measured. The inspired volumes of the corresponding cycles were systematically recorded using a spirometer. The indices were calculated using the ratio excursion, or percentage of thickening, divided by the corresponding breathing volume. From this corhort, normal values and limit values for normality were determined. These measurements were compared to those performed on the healthy side in patients with hemidiaphragm paralysis because an increase in hemidiaphragm activity has been previously demonstated in such circumstances., Results: A total of 122 subjects (51 women, 71 men) with normal pulmonary function were included in the study. Statistical analysis revealed that the ratio of excursion, or percentage of thickening, to inspired volume ratio significantly differed between males and females. When the above-mentioned indices using excursion were normalized by body weight, no gender differences were found. The indices differed between normal respiratory function subjects and patients with hemidiaphragm paralysis (27 women, 41 men). On the paralyzed side, the average ratio of the excursion divided by the inspired volume was zero. On the healthy side, the indices using the excursion and the percentage of thickening during quiet breathing or deep inspiration were significantly increased comparedto patients with normal lung function. According to the logistic regression analysis, the most relevant indice appeared to be the ratio of the excursion measured during quiet breathing to the inspired volume., Conclusion: The normal values of the diaphragm motion-volume indices could be useful to estimate the performance of the respiratory system. Proposed indices appear suitable in a context of hyperactivity., Competing Interests: GC was employed by AltraBio. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Boussuges, Chaumet, Boussuges, Menard, Delliaux and Brégeon.)

Introduction: In mechanically ventilated adults, thickening fraction of diaphragm (dTF) measured by ultrasound is used to predict extubation success. Whether dTF can also predict extubation success in children is unclear., Aim: To investigate the association between dTF and extubation success in children. Second, to assess diaphragm thickness during ventilation and the correlation between dTF, diaphragm thickness (Tdi), age and body surface., Method: Prospective observational cohort study in children aged 0-18 years old with expected invasive ventilation for >48 h. Ultrasound was performed on day 1 after intubation (baseline), day 4, day 7, day 10, at pre-extubation, and within 24 h after extubation. Primary outcome was the association between dTF pre-extubation and extubation success. Secondary outcome measures were Tdi end-inspiratory and Tdi end-expiratory and atrophy defined as <10% decrease of Tdi end-expiratory versus baseline at pre-extubation. Correlations were calculated with Spearman correlation coefficients. Inter-rater reliability was calculated with intraclass correlation (ICC)., Results: Fifty-three patients, with median age 3.0 months (IQR 0.1-66.0) and median duration of invasive ventilation of 114.0 h (IQR 55.5-193.5), were enrolled. Median dTF before extubation with Pressure Support 10 above 5 cmH 2 O was 15.2% (IQR 9.7-19.3). Extubation failure occurred in six children, three of whom were re-intubated and three then received non-invasive ventilation. There was no significant association between dTF and extubation success; OR 0.33 (95% CI; 0.06-1.86). Diaphragmatic atrophy was observed in 17/53 cases, in three of extubation failure occurred. Children in the extubation failure group were younger: 2.0 months (IQR 0.81-183.0) vs. 3.0 months (IQR 0.10-48.0); p  = 0.045. At baseline, pre-extubation and post-extubation there was no significant correlation between age and BSA on the one hand and dTF, Tdi- insp and Tdi-exp on the other hand. The ICC representing the level of inter-rater reliability between the two examiners performing the ultrasounds was 0.994 (95% CI 0.970-0.999). The ICC of the inter-rater reliability between the raters in 36 paired assessments was 0.983 (95% CI 0.974-0.990)., Conclusion: There was no significant association between thickening fraction of the diaphragm and extubation success in ventilated children., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2023 Duyndam, Smit, Houmes, Heunks, Molinger, IJland, van Rosmalen, Van Dijk, Tibboel and Ista.)

Background: SARS-CoV-2 infection can impair diaphragm function at the acute phase but the frequency of diaphragm dysfunction after recovery from COVID-19 remains unknown., Materials and Methods: This study was carried out on patients reporting persistent respiratory symptoms 3-4 months after severe COVID-19 pneumonia. The included patients were selected from a medical consultation designed to screen for recovery after acute infection. Respiratory function was assessed by a pulmonary function test, and diaphragm function was studied by ultrasonography., Results: In total, 132 patients (85M, 47W) were recruited from the medical consultation. During the acute phase of the infection, the severity of the clinical status led to ICU admission for 58 patients (44%). Diaphragm dysfunction (DD) was detected by ultrasonography in 13 patients, two of whom suffered from hemidiaphragm paralysis. Patients with DD had more frequently muscle pain complaints and had a higher frequency of prior cardiothoracic or upper abdominal surgery than patients with normal diaphragm function. Pulmonary function testing revealed a significant decrease in lung volumes and DLCO and the dyspnea scores (mMRC and Borg10 scores) were significantly increased in patients with DD. Improvement in respiratory function was recorded in seven out of nine patients assessed 6 months after the first ultrasound examination., Conclusion: Assessment of diaphragm function by ultrasonography after severe COVID-19 pneumonia revealed signs of dysfunction in 10% of our population. In some cases, ultrasound examination probably discovered an un-recognized pre-existing DD. COVID-19 nonetheless contributed to impairment of diaphragm function. Prolonged respiratory physiotherapy led to improvement in respiratory function in most patients., Clinical Trial Registration: [www.cnil.fr], identifier [#PADS20-207]., Competing Interests: GC was employed by ALTRA BIO. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as potential conflicts of interest., (Copyright © 2022 Boussuges, Habert, Chaumet, Rouibah, Delorme, Menard, Million, Bartoli, Guedj, Gouitaa, Zieleskiewicz, Finance, Coiffard, Delliaux and Brégeon.)

Background: Diagnosing diaphragm dysfunction in the absence of complete paralysis remains difficult. The aim of the present study was to assess the normal values of the thickness and the inspiratory thickening of both hemidiaphragms as measured by ultrasonography in healthy volunteers while in a seated position. Methods: Healthy volunteers with a normal pulmonary function test were recruited. The diaphragmatic thickness was measured on both sides at the zone of apposition of the diaphragm to the rib cage during quiet breathing at end-expiration, end-inspiration, and after maximal inspiration. The thickening ratio, the thickening fraction, and the thickness at end-inspiration divided by the thickness at deep breathing were determined. The mean values and the lower and upper limits of normal were determined for men and women. Results: 200 healthy volunteers (100 men and 100 women) were included in the study. The statistical analysis revealed that women had a thinner hemidiaphragm than men on both sides and at the various breathing times studied. The lower limit of normality of the diaphragm thickness measured at end-expiration was estimated to be 1.3 mm in men and 1.1 mm in women, on both sides. The thickening fraction did not differ significantly between men and women. In men, it ranged from 60 to 260% on the left side and from 57 to 200% on the right side. In women, it ranged from 58 to 264% on the left side and from 60 to 229% on the right side. The lower limits of normality of the thickening fraction were determined to be 40 and 39% in men and 39 and 48% in women for the right and left hemidiaphragms, respectively. The upper limit for normal of the mean of both sides of the ratio thickness at end-inspiration divided by the thickness at deep breathing was determined to be 0.78 in women and 0.79 in men. Conclusion: The normal values of thickness and the indexes of diaphragmatic function should help clinicians with detecting diaphragm atrophy and dysfunction., Competing Interests: GC was employed by ALTRA BIO SA. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Boussuges, Rives, Finance, Chaumet, Vallée, Risso and Brégeon.)