Acute exacerbations of chronic obstructive pulmonary disease (COPD) are associated with compromised diaphragmatic function. This can be evaluated using point-of-care ultrasound. The association of diaphragm function with hospital length of stay or mortality has not been assessed earlier. This study aimed to evaluate the correlation of diaphragmatic function with length of hospital stay, mortality, and non-invasive ventilation (NIV) failure in severe acute exacerbation of COPD. Diaphragmatic excursion and thickening index (Tdi) were evaluated with ultrasound-guided assessment in individuals with severe acute exacerbation of COPD at the time of hospitalization. The individuals were evaluated for length of stay in survivors, NIV ventilation failure in those requiring NIV therapy, and mortality in non-survivors. A total of 110 individuals were screened, and 60 of these were enrolled. A total of 55 individuals survived, and 5 died. The length of stay had a negative correlation with excursion (R: -0.78, p<0.001) and Tdi (R: -0.96, p<0.001). The excursion and Tdi were smaller by 30% and 50%, respectively, in the event of NIV failure compared to NIV success. Excursion ≤1.96 cm [area under receiver-operating characteristic curve (AUROC): 0.958] or Tdi≤92% (AUROC: 0.974) were associated with length of stay ≥8 days. Excursion ≤1.48 cm (AUROC: 0.75) or Tdi≤51.2% (AUROC: 0.8) were associated with NIV failure. Tdi≤40% was associated with a high risk of mortality (RR: 22.67, p=0.035). Smaller diaphragmatic excursion, or Tdi, correlated with prolonged LoS, mortality, and NIV failure.

Diaphragmatic dysfunction is an important contributor to hypercapnic respiratory failure, but its presence is often challenging to determine at the bedside. Diaphragm ultrasound provides an opportunity to evaluate the function of the diaphragm noninvasively by evaluating the following parameters that can help define diaphragmatic dysfunction: diaphragm excursion, diaphragm muscle thickness, and thickening fraction. Its evaluation has the potential to assist with diagnosis of respiratory failure, provide prognosis, and assist with patient monitoring and should be considered as part of an internal medicine physician's and emergency physician's skill set. This article provides an overview on how to perform diaphragm ultrasound, review its pitfalls, and discuss the evidence of its use in patients with neuromuscular disorders and chronic obstructive pulmonary disease. Finally, its potential emerging uses in the perioperative setting and for evaluation of acute heart failure are discussed.

This study aimed to establish normal reference values for multimodal diaphragmatic ultrasound indices in healthy adult volunteers and evaluate intra-and inter-observer consistency between ultrasound physicians and critical care physicians.

An ultrasound physician (US physician) used techniques such as B-mode, M-mode, Tissue Doppler Imaging (TDI), and shear wave elastography (SWE) to measure diaphragmatic parameters in 46 healthy adults during quiet and deep breathing. A critical care physician (CC physician) trained in diaphragmatic ultrasound repeated these measurements. Consistency was analyzed in intra-researcher and inter-researchers of various diaphragmatic ultrasound indicators.

Diaphragm thickness at the end of expiration, end of inspiration, and end of deep inspiration (DT-ee, DT-ei, and DT-edi) in both B-mode and M-mode method of males were higher than that of females, Diaphragm shear modulus-edi of males is higher than that of females (P<0.05). Between different diaphragmatic ultrasound indicators, the study showed a moderate consistency of peak contraction velocity (PCV) and peak relaxation velocity (PRV) in intra-researcher of CC physician and inter-researchers between US physician and CC physician, (ICC = 0.678 and 0.704, P < 0.001). For other multiple diaphragm ultrasound indicators, our study showed an excellent consistency in both intra-researcher and inter-researchers (ICC = 0.824-0.994, P < 0.001). For DT measurement by B-mode and M-mode, it showed an excellent consistency in both intra-researcher, intra-researcher of US physician, intra-researcher of CC physician and total cases (ICC = 0.919-0.960, P < 0.001). Correlation analysis showed a moderate positive correlation between diaphragm displacement during quiet breathing (DD-qb) and pleural sliding displacement (PSD) in US physician (r = 0.568), CC physician (r = 0.470), and total cases (r = 0.511), with significant differences (P < 0.05).

Ultrasound-based assessment of diaphragmatic function is a reliable method. This study provides normal reference values and highlights the high observer reproducibility among experienced ultrasound and critical care physicians.

Despite the understanding of the role of diaphragm role as a crucial element in trunk stabilizer performance, limited research has been carried out on the diaphragmatic features particularly in smoking population.

It was aimed to compare the diaphragm structure beside trunk stabilizer performance & body balance of young regular smokers and non-smokers and investigate the relationship between diaphragmatic features and physical performance in regular smokers.

Asymptomatic regular smoker (n = 22) and nonsmoker (n = 22) young male subjects (21.63 ± 2.37 years) were participated to the study. The diaphragmatic ultrasonic scanning and physical performance tests of core muscle strength and endurance & Y balance test were performed.

The duration of prone and lateral side bridge (t = -3.347, t = 3.477, p < 0.001), and modify push-up test repetition (Z = -2.213, p = 0.027) were detected lower in regular smokers. A positive moderate correlation was observed between the duration of the prone bridge test and the maximum inspiration thickness & the thickness difference at inspiration and expiration (r = 0.545, p = 0.009 & r = 0.468, p = 0.028) and between the number of repetitions of the modify push-up and the maximum expiration thickness (r = 0.530, p = 0.011).

While no difference was detected in terms of the diaphragm structure between groups, trunk stabilizer performance was lower and greater diaphragm thickness was associated with better trunk stability in some performance tasks in smokers. While the diaphragm muscle structure, which is the main respiratory muscle, does not differ in young smokers, the effects of the diaphragm muscle on general body biomechanics have been preliminary demonstrated.

Diaphragm ultrasound makes it possible to diagnose diaphragmatic atrophy and dysfunction. Important indications include unclear dyspnea; diaphragmatic elevation; assessment of diaphragm dysfunction in pulmonary, neuromuscular and neurovascular diseases; and in critically ill patients before noninvasive and mechanical ventilation and follow-up of diaphragm thickness and function during mechanical ventilation with potential prediction of prolonged weaning. In patients with respiratory insufficiency and potential diaphragm dysfunction, it is possible to objectify the contribution of diaphragm dysfunction. In addition, assessment of diaphragmatic hernias, tumors and diaphragmatic dysfunction in COVID-19 and diaphragmatic ultrasound in sports medicine have been described. This narrative review includes the sonomorphology of the diaphragm, standardization of ultrasonographic investigation with transducer positions and ultrasound techniques, normal findings and diagnostic criteria for pathological findings. The correct sonographic measurement, calculation and evaluation can ultimately influence further therapeutic procedures for the patient suffering from diaphragm dysfunction in various diseases.

The diaphragm is crucial for ventilator weaning, but its specific impact on weaning indicators needs further clarification. This study investigated the variability in weaning outcomes across different diaphragm function populations and the value of respiratory drive and inspiratory effort in weaning.

This observational case-control study enrolled patients on mechanical ventilation for more than 48 h and completed a 30-minute spontaneous breathing trial (SBT) with pressure-support ventilation for the first time. After the SBT, airway pressure at 100 ms during occlusion (P0.1), inspiratory effort, and diaphragmatic ultrasound were evaluated to predict weaning outcomes. Weaning failure was defined as re-intubation within 48 h of weaning, the need for therapeutic non-invasive ventilation, or death.

68 patients with a mean age of 63.21 ± 15.15 years were included. In patients with diaphragm thickness (DT) ≥ 2 mm, P0.1 (P=0.002), pressure-muscle index (PMI) (P=0.012), and occluded expiratory airway pressure swing (ΔPocc) (P=0.030) were significantly higher in those who failed weaning. Conversely, for patients with DT<2 mm, PMI (P=0.003) and ΔPocc (P=0.002) were lower in the weaning failure group. Additionally, within the DT≥2 mm group, P0.1 demonstrated a higher area under the curve (AUC) for weaning prediction (0.889 vs. 0.739) compared to those with DT<2 mm.

PMI and ΔPocc are predictive of weaning outcomes in patients with diaphragm thickness ≥ 2 mm, where the assessment value of P0.1 is notably higher. Diaphragm function significantly influences the accuracy of weaning predictions based on respiratory drive and inspiratory effort.

Our findings indicate that the effectiveness of respiratory drive and inspiratory effort in predicting successful weaning from mechanical ventilation may vary across different patient populations. Diaphragm function plays a crucial role in weaning assessments, particularly when using P0.1, the pressure-muscle index (PMI), and occluded expiratory airway pressure swing (ΔPocc).

Diaphragm dysfunction is frequently observed in patients with pleural effusion. The aim of the study was to determine the criteria for estimating the impact of pleural fluid on diaphragm function and detecting impairment of diaphragmatic muscle.

This was a retrospective observational study carried out in a university hospital. Cases of free pleural effusion were recruited from the ultrasound consultation of the lung function test laboratory. The quantification of pleural effusion and analysis of diaphragmatic function were performed using chest ultrasound performed while sitting. In case of abnormal diaphragmatic motion, the examination was repeated in supine position.

109 pleural effusions (57 left, 52 right) were included in the analysis. Pleural effusions were detected after thoracic surgery in 89% of cases and in the context of medical disease in other cases. Excursion during deep inspiration was reduced by the amount of fluid (4.3 ± 2.1 cm for small effusions, 3.2 ± 1.7 cm for moderate effusions and 1.1 ± 1.8 cm for large effusions). In 23 cases of large pleural effusion, the excursions during deep inspiration were always below the lower limit of normal. In some cases, a paradoxical motion suggesting hemidiaphragm paralysis was observed. When the inspiratory thickening was normal, the paradoxical excursions disappeared in supine position. In moderate pleural effusion (53 cases), hemidiaphragm excursion was above lower limit of normal in 68% of cases. In cases of paradoxical motions, repeated ultrasound examinations were in favor of hemidiaphragm paralysis. In small pleural effusion (32 cases) the excursion was most often normal.

The ultrasound analysis of diaphragm excursion and thickening in sitting and supine positions is useful to assess the impact of pleural effusion and detect impairment in diaphragm muscle function.

Background/Objectives: The effects of ageing on the diaphragm are unclear. This study examined the association between ageing and diaphragm thickness, thickening fraction (TF), and diaphragm excursion (DE) as assessed by ultrasonography after adjusting for other factors. The relationship between these parameters and maximal inspiratory pressure (MIP) was also investigated. Methods: From 2022 to 2024, ambulatory and communicative adult volunteers and outpatients were recruited from four Japanese medical institutions. Each participant's background factors (including height, weight, and underlying diseases) and pulmonary function test results were assessed. Diaphragm thickness, TF, and DE were evaluated using ultrasonography. Results: The study involved 230 individuals with a mean age of 55.5 years (older adults (65 years and over), n = 117; non-older adults, n = 113). In older adults, the diaphragm was thicker (2.1 vs. 1.7 mm, p < 0.001), and TF was lower (88.7% vs. 116.0%, p < 0.001), with no significant difference in DE. Multivariate linear regression analysis adjusted for sex, height, body mass index, and underlying diseases showed positive associations between age and diaphragm thickness (p = 0.001), but not with TF or DE. MIP was positively associated with DE (p < 0.001) but not with thickness or TF. Age was negatively associated with MIP, regardless of diaphragm thickness, TF, and DE (all p < 0.001). Conclusions: As the diaphragm thickens with age, neither thickness nor TF is associated with MIP; only DE is related to MIP. Additionally, ageing is negatively associated with MIP, independent of diaphragm thickness, TF, and DE. Diaphragm function should be assessed using DE rather than thickness or TF.

The diaphragm is considered the main inspiratory muscle, and as such, its assessment is crucial in patients with respiratory pathology. It is known that the contractile capacity of a muscle is determined by strength, length, and the duration of contraction. Although transdiaphragmatic pressure is the gold standard test for its study, ultrasound has been confirmed as a useful tool in clinical practice. Thanks to it, both the strength (diaphragmatic thickness) and the length of movement (diaphragmatic excursion) can be evaluated. This study aims to investigate the relationship between the inspiratory time and the diaphragmatic contraction.

Cross-sectional controlled study.

Eighty healthy subjects, yoga practitioners, with no previous respiratory pathology participated in this study. They were asked to take three different types of deep breaths: diaphragmatic with nasal inspiration, pursed-lip inspiration, and ujjayi (nasal inspiration with slight contraction of the glottis). The variables of thickness, excursion, and inspiratory contraction time were taken for each of them by ultrasound.

Diaphragmatic contraction time is the only variable that shows a significant correlation with the other two. Thus, the correlation between inspiratory time and diaphragmatic thickness is significant (p < .001) for the three breaths: diaphragmatic (0.60), ujjayi (0.67), and pursed lips (0.39) and the correlation between inspiratory time and diaphragmatic excursion is significant for diaphragmatic breaths (-0.24, p = .035) and ujjayi (0.27, p = .017), but not in pursed lips (-0.01, p = .90).

The inspiratory contraction time and the diaphragmatic excursion are two essential variables in the dynamic functional evaluation of the diaphragm, compared to the diaphragmatic thickness measurement that only reports its strength.

Chronic Obstructive Pulmonary Disease (COPD) is a prevalent condition that poses a significant burden on individuals and society due to its high morbidity and mortality rates. The diaphragm is the main respiratory muscle, its function has a direct impact on the quality of life and prognosis of COPD patients. This article aims to review the structural measurement and functional evaluation methods through the use of diaphragmatic ultrasound and relevant research on its application in clinical practice for COPD patients. Thus, it serves to provide valuable insights for clinical monitoring of diaphragm function in COPD patients, facilitating early clinical intervention and aiding in the recovery of diaphragm function.

Background: It is known that the consumption of single phytochemicals improves respiratory function in chronic obstructive pulmonary disease (COPD) patients. Since phytochemicals have a synergistic effect on health, a more comprehensive analysis is needed. The aim of this study was to estimate the intake of phytochemicals using the dietary phytochemical index (DPI) and assess their association with respiratory function, inspiratory muscle strength and function, and peripheral muscle strength. Methods: This study was conducted at the Special Hospital for Pulmonary Diseases in Zagreb (September 2023 to May 2024). The DPI was assessed using three 24 h recalls from 71 COPD patients (66.5 ± 8.4 years; 53.5% men). Anthropometric measurements, respiratory function, inspiratory muscle function and strength, and peripheral muscle strength were assessed during pulmonary rehabilitation following standard protocols. Results: Patients were divided into DPI tertiles with mean values of 7.3 ± 3.0, 16.0 ± 3.0, and 32.2 ± 8.8, respectively. After controlling for confounding factors, a significant association was found between DPI tertiles and FEV1 (p-trend < 0.001), FVC (p-trend = 0.002), FEV1/FVC (p-trend < 0.001), MIP (p-trend = 0.012), and MSUE (p-trend = 0.002). In addition, an inverse association was found between DPI tertiles and diaphragm thickness during inhalation (p-trend = 0.012) and exhalation (p-trend = 0.013). Conclusions: This study suggests that a higher intake of phytochemicals could be beneficial in dietary interventions for COPD therapy. Future prospective studies are needed to confirm these findings.

In recent years, diaphragm ultrasound (DUS) has been used to identify diaphragm dysfunction in the intensive care unit (ICU). However, there are few studies on DUS parameters to evaluate function, normal ranges, and influencing factors in population. The aim of this study is to provide a methodological reference for clinical evaluation of diaphragm function by measuring different DUS parameters in a healthy population.

A descriptive study was conducted 212 (105 males, 107 females) subjects with normal spirometry underwent ultrasound imaging in this study. The diaphragm contraction and motion related parameters and shear wave velocity (SWV) were measured in the supine position. The effects of gender, age, body mass index (BMI) and lifestyle on diaphragm ultrasound parameters were analyzed.

The diaphragm thickness at end-expiration (DT-exp) was 0.14 ±0.05 cm, the diaphragm thickness at end- inspiration (DT-insp) was 0.29±0.10 cm, with thickening fraction (TF) was 1.11±0.54. The diaphragm excursion (DE) was 1.68±0.37cm and diaphragm velocity was 1.45±0.41 cm/s during calm breathing. During deep breathing, the DE was 5.06±1.40cm and diaphragm velocity was 3.20±1.18 cm/s. The Diaphragm shear modulus-longitudinal view were Mean16.72±4.07kPa, Max25.04±5.58kPa, Min11.06±3.88kPa, SD2.56±0.98. The results of diaphragmatic measurement showed that the DT of males was significantly greater than that of females (P< 0.05), but there was no significant difference in TF. The DT-insp (r=0.155, P= 0.024) and the DT-exp (r=0.252, P=0.000) were positively correlated with age, and the DE during calm breathing was negatively correlated with age (r=-0.218, P= 0.001) and BMI (r=-00.280, P= 0.000). The DE (R=0.371, P=0.000) and velocity (R=0.368, P=0.000) during deep breathing were correlated with lifestyle.

Our study provides normal reference values of the diaphragm and evaluates the influence of gender, age, body mass index and lifestyle on diaphragmatic morphology.

Background: Diaphragmatic dysfunction correlates with weaning failure, highlighting the need to independently assess the diaphragm's effects on weaning. We modified the rapid shallow breathing index (RSBI), a predictor of successful weaning, by incorporating temporal variables into existing ultrasound-derived diaphragm index to create a simpler index closer to tidal volume. Methods: We conducted a prospective observational study of patients who underwent a spontaneous breathing trial in the medical intensive care unit (ICU) at Severance Hospital between October 2022 and June 2023. Diaphragmatic displacement (DD) and diaphragm inspiratory time (Ti) were measured using lung ultrasonography. The modified RSBI was defined as follows: respiratory rate (RR) divided by DD was defined as D-RSBI, and RR divided by the sum of the products of DD and Ti on both sides was defined as DTi-RSBI. Results: Among the sonographic indices, DTi-RSBI had the highest area under the receiver operating characteristic (ROC) curve of 0.774 in ROC analysis, and a correlation was found between increased DTi-RSBI and unsuccessful extubation in a multivariable logistic regression analysis (adjusted odds ratio 0.02, 95% confidence interval 0.00-0.97). Conclusions: The DTi-RSBI is beneficial in predicting successful weaning in medical ICU patients.

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

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.

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.

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.

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.

Skeletal muscle weakness and wasting also occurs in the respiratory muscles, called respiratory sarcopenia. Respiratory sarcopenia may lead to worse clinical indicators and outcomes. We present a novel definition and diagnostic criteria for respiratory sarcopenia, summarize recent reports on the association between respiratory sarcopenia, physical and nutritional status, and clinical outcomes, and provide suggestions for the prevention and treatment of respiratory sarcopenia.

Recently, a novel definition and diagnostic criteria for respiratory sarcopenia have been prepared. Respiratory sarcopenia is defined as a condition in which there is both low respiratory muscle strength and low respiratory muscle mass. Respiratory muscle strength, respiratory muscle mass, and appendicular skeletal muscle mass are used to diagnose respiratory sarcopenia. Currently, it is challenging to definitively diagnose respiratory sarcopenia due to the difficulty in accurately determining low respiratory muscle mass. Decreased respiratory muscle strength and respiratory muscle mass are associated with lower physical and nutritional status and poorer clinical outcomes. Exercise interventions, especially respiratory muscle training, nutritional interventions, and their combinations may effectively treat respiratory sarcopenia. Preventive interventions for respiratory sarcopenia are unclear.

The novel definition and diagnostic criteria will contribute to promoting the assessment and intervention of respiratory sarcopenia.

In recent years, lung ultrasound (LUS) has developed rapidly, and it is gaining growing popularity in various scenarios. There are constant attempts to introduce it to new fields. In addition, knowledge regarding lung and LUS has been augmented by the recent COVID-19 pandemics. In the first part of this review we discuss lines, signs and pheno-mena, profiles, some applications, and misconceptions. An aim of the second part of the review is mainly to discuss some advanced applications of LUS, including lung elastography, lung spectroscopy, colour and spectral Doppler, contrast-enhanced ultrasound of lung, speckled tracking of pleura, quantification of pulmonary oedema, predicting success of talc pleurodesis, asthma exacerbations, detecting chest wall invasion by tumours, lung biopsy, estimating pleural effusion volume, and predicting mechanical ventilatory weaning outcome. For this purpose, we reviewed literature concerning LUS.

Although a growing body of evidence emphasizes the superiority of VATS over conventional thoracotomy, little is still known about early postoperative diaphragm muscle function after lobectomy via these two approaches. To fill the gap in existing literature, we conducted a comparative study between VATS and conventional thoracotomy in terms of postoperative diaphragm muscle function, assessing its contractility, strength, the magnitude of effort and potential risk of dysfunction such as atrophy and paralysis. A total of 59 patients (30 after VATS), who underwent anatomical pulmonary resection at our institution, were enrolled in this study. The control group consisted of 28 health subjects without medical conditions that could contribute to diaphragm dysfunction. Diaphragm muscle was assessed before and after surgery using ultrasonography. We found that both surgical approaches were associated with postoperative impairment of diaphragm muscle function-compared to baseline data. Postoperative reduction in diaphragm contraction was demonstrated in most of the 59 patients. In the case of the control group, the differences between measurements were not observed. We noted that lobectomy via thoracotomy was linked with a greater percentage of patients with diaphragm paralysis and/or atrophy than VATS. Similar findings were observed in referring to diaphragm magnitude effort, as well as diaphragm contraction strength, where minimally invasive surgery was associated with better diaphragm function parameters-in comparison to thoracotomy. Disturbance of diaphragm work was reported both at the operated and non-operated side. Upper-right and left lobectomy were connected with greater diaphragm function impairment than other segments. In conclusion, the VATS technique seems to be less invasive than conventional thoracotomy providing a better postoperative function of the main respiratory muscle.

Diaphragm ultrasonography is used to identify causes of diaphragm dysfunction. However, its correlation with pulmonary function tests, including maximal inspiratory (MIP) and expiratory pressures (MEP), remains unclear. This study investigated this relationship by measuring diaphragm thickness, thickening fraction (TF), and excursion (DE) using ultrasonography, and their relationship to MIP and MEP. It also examined the influence of age, sex, height, and BMI on these measures.

We recruited healthy Japanese volunteers and conducted pulmonary function tests and diaphragm ultrasonography in a seated position. Diaphragm ultrasonography was performed during quiet breathing (QB) and deep breathing (DB) to measure the diaphragm thickness, TF, and DE. A multivariate analysis was conducted, adjusting for age, sex, height, and BMI.

Between March 2022 and January 2023, 109 individuals (56 males) were included from three facilities. The mean (standard deviation) MIP and MEP [cmH2O] were 72.2 (24.6) and 96.9 (35.8), respectively. Thickness [mm] at the end of expiration was 1.7 (0.4), TF [%] was 50.0 (25.9) during QB and 110.7 (44.3) during DB, and DE [cm] was 1.7 (0.6) during QB and 4.4 (1.4) during DB. Multivariate analysis revealed that only DE (DB) had a statistically significant relationship with MIP and MEP (p = 0.021, p = 0.008). Sex, age, and BMI had a statistically significant influence on relationships between DE (DB) and MIP (p = 0.008, 0.048, and < 0.001, respectively).

In healthy adults, DE (DB) has a relationship with MIP and MEP. Sex, age, and BMI, but not height, are influencing factors on this relationship.

Thoracic ultrasound has attracted much interest in detecting pleural effusion or pulmonary consolidation after cardiac surgery. In 2016, Trovato reported, in the World Journal of Cardiology, the interest of using, in addition to echocardiography, thoracic ultrasound. In this editorial, we highlight the value of assessing diaphragm function after cardiac surgery and interventional cardiology procedures. Various factors are able to impair diaphragm function after such interventions. Diaphragm motion may be decreased by chest pain secondary to sternotomy, pleural effusion or impaired muscle function. Hemidiaphragmatic paralysis may be secondary to phrenic nerve damage complicating cardiac surgery or atrial fibrillation ablation. Diagnosis may be delayed. Indeed, respiratory troubles induced by diaphragm dysfunction are frequently attributed to pre-existing heart disease or pulmonary complications secondary to surgery. In addition, elevated hemidiaphragm secondary to diaphragm dysfunction is sometimes not observed on chest X-ray performed in supine position in the intensive care unit. Analysis of diaphragm function by ultrasound during the recovery period appears essential. Both hemidiaphragms can be studied by two complementary ultrasound methods. The mobility of each hemidiaphragms is measured by M-mode ultrasonography. In addition, recording the percentage of inspiratory thickening provides important information about the quality of muscle function. These two approaches make it possible to detect hemidiaphragm paralysis or dysfunction. Such a diagnosis is important because persistent diaphragm dysfunction after cardiac surgery has been shown to be associated with adverse respiratory outcome. Early respiratory physiotherapy is able to improve respiratory function through strengthening of the inspiratory muscles i.e. diaphragm and accessory inspiratory muscles.

Computed tomography (CT) is routinely employed on the evaluation of dyspnea, yet limited data exist on its assessment of diaphragmatic muscle. This study aimed to determine the capability of CT in identifying structural changes in the diaphragm among patients with ultrasound-confirmed diaphragmatic dysfunction.

Diaphragmatic ultrasounds conducted between 2018 and 2021 at our center in Marseille, France, were retrospectively collected. Diaphragmatic pillars were measured on CT scans at the L1 level and the celiac artery. Additionally, the difference in height between the two diaphragmatic domes in both diaphragmatic dysfunction cases and controls was measured and compared.

A total of 65 patients were included, comprising 24 with diaphragmatic paralysis, 13 with diaphragmatic weakness, and 28 controls. In the case group (paralysis and weakness) with left dysfunctions (n = 24), the CT thickness of the pillars at the level of L1 and the celiac artery was significantly thinner compared with controls (2.0 mm vs. 7.4 mm and 1.8 mm vs. 3.1 mm, p < 0.001 respectively). Significantly different values were observed for paralysis (but not weakness) in the right dysfunction subgroup (n = 15) (2.6 mm vs. 7.4 mm and 2.2 mm vs. 3.8 mm, p < 0.001 respectively, for paralysis vs. controls). Regardless of the side of dysfunction, a significant difference in diaphragmatic height was observed between cases and controls (7.70 cm vs. 1.16 cm and 5.51 cm vs. 1.16 cm, p < 0.001 for right and left dysfunctions, respectively). Threshold values determined through ROC curve analyses for height differences between the two diaphragmatic domes, indicative of paralysis or weakness in the right dysfunctions, were 4.44 cm and 3.51 cm, respectively. Similarly for left dysfunctions, the thresholds were 2.70 cm and 2.48 cm, respectively, demonstrating good performance (aera under the curve of 1.00, 1.00, 0.98, and 0.79, respectively).

In cases of left diaphragmatic dysfunction, as well as in paralysis associated with right diaphragmatic dysfunction, CT revealed thinner pillars. Additionally, a notable increase in the difference in diaphragmatic height demonstrated a strong potential to identify diaphragmatic dysfunction, with specific threshold values.

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.

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.

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.

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.

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.

COVID-19 pneumonia results in an impairment of the diaphragmatic musculature that influences the development of respiratory failure during the patient's hospitalization. Diaphragmatic ultrasound is a useful, non-invasive, and accessible tool for measuring the function of this muscle.

Assessing the morphological and functional ultrasound status of the diaphragm in patients admitted within the first 24 h for COVID-related pneumonia and its association with hospital morbidity and mortality (NCT05805579).

Observational, prospective cohort study that included 68 patients admitted for COVID-19 pneumonia with respiratory failure. Diaphragmatic ultrasound was performed within the first 24 h of admission to the pulmonology ward. Clinical, analytical, and ultrasound variables were collected: excursion, thickness, and diaphragmatic shortening fraction (DSF). DSF < 20% was used to define diaphragmatic dysfunction (DD). Patients who showed favorable progression and were managed on the ward (HCONV) were compared to those who required admission to the respiratory monitoring unit (RMU).

A total of 68 patients were included, of which 22 (32.35%) were admitted to the RMU. Diaphragmatic excursion at maximum volume was higher in the HCONV group compared to the RMU group (58.41 ± 17.83 vs. 50.03 ± 16.23; p = 0.123). Diaphragmatic dysfunction (DD) was observed in 21 (30.88%) patients, with a higher prevalence in the RMU group than in the HCONV group (15 (68.18%) vs. 6 (13.04%); p = 0.0001). In the multivariate analysis, age and DSF at admission were the best predictors of failure to discharge.

Performing diaphragmatic ultrasound to assess mobility and DSF within the first 24 h of admission for COVID-19 pneumonia proves valuable in determining short-term progression and the need for admission to a respiratory monitoring unit.

Ultrasonography is an emerging tool that helps to assess diaphragmatic function. It is now widely used in ICUs to predict weaning from mechanical ventilation. Ultrasonography is readily available, harmless (no radiation), and repeatable with good interoperator reproducibility. Over the past few years, ultrasonography has seen increasing use in patients with chronic pulmonary pathologies.

The aim of this review is (1) to describe the ultrasound techniques used to assess diaphragmatic excursion and thickening, (2) to indicate the expected, normal values in healthy patients, and (3) to summarize the main findings and clinical applications in treatment of chronic respiratory disorders.

Chronic pulmonary diseases are associated with diaphragmatic dysfunction that can be assessed with ultrasound. Diaphragmatic dysfunction is primary in neuromuscular disorders and secondary to respiratory disease in other chronic pulmonary conditions (COPD, ILD). Ultrasound is correlated with the severity of the underlying disease (functional and clinical parameters).

The prognostic interest of diaphragm ultrasonography remains to be established, after which its utilization should become routine.

Diaphragmatic dysfunction (DD) is defined as a weakening of the diaphragmatic muscle and can be an undetected cause of dyspnea. The objectives of this study were to explore the appropriate diaphragmatic location, measure diaphragmatic thickness (DT), evaluate the effect of intrinsic factors on DT, and compare DT between healthy and diseased cats, using 33 healthy cats and 15 diseased cats. A retrospective, analytical, case-control study using thoraco-abdominal feline computed tomography (CT) was performed. Two radiologists independently reviewed all images to verify inter- and intra-observer reliabilities and the best position for measuring DT. The effects of sex, age, and body weight were also studied, and cutoff values for detecting DT abnormalities were established. The results showed that the appropriate location for DT measurement was at the ventral border of the cranial endplate of the first lumbar vertebral body (L1) due to its highest intra- and inter-observer reliabilities. At this location, a significant difference in DT between the right and left hemidiaphragms (p = 0.01) was observed. Only sex had an impact on DT values. Interestingly, the DTs of cardiorespiratory-affected cats, both on the right and left sides, were significantly thinner than those of healthy cats. In conclusion, CT imaging is a reliable imaging method for determining diaphragmatic muscular atrophy. The ventral border of the cranial endplate of L1 is recommended for measuring the DT, and sex was the only factor affecting the DT measurement.

Amyotrophic lateral sclerosis (ALS) leads to diaphragmatic weakness at some point during its course, which is a major cause of respiratory insufficiency. The aim of this study was to evaluate ultrasound-based measures for assessing the diaphragmatic competency and the need for ventilatory support.

Twenty-six subjects with ALS and 12 healthy controls were enrolled. All participants underwent B-mode diaphragm ultrasound (DUS). Diaphragm thickness and thickening indices were recorded. In the subjects with ALS, further assessments included functional scales and spirometry. We investigated the diagnostic accuracy of DUS thickening indices in predicting diaphragmatic dysfunction and the correlation between clinical, spirometric, and DUS data.

Significant relationships were found between forced vital capacity and all diaphragmatic thickening indices. Similarly, all diaphragmatic thickening indices correlated with both Milano Torino staging and disease progression rate. Only thickening fraction (TFdi) correlated with score on the revised ALS Functional Rating Scale (r = 0.459, P = .024). TFdi had better accuracy in predicting diaphragmatic dysfunction (area under the curve [AUC] = 0.839, 95% confidence interval [CI] 0.643 to 0.953) and the need for initiation of noninvasive ventilation (NIV) (AUC = 0.989, 95% CI 0.847 to 1.000) compared with the other indices. A TFdi cut-off point of 0.50 was a sensitive threshold to consider NIV.

DUS successfully identifies diaphragmatic dysfunction in ALS, being a valuable accessory modality for investigating respiratory symptoms. TFdi was found to be the most useful DUS index, which encourages further investigation.

The diaphragm function assessed by ultrasound has been well-studied in COPD, asthma, and intensive care. However, there are only a few studies on diffuse interstitial lung disease, while dyspnea and quality of life are major issues in the management that may depend on the diaphragm.

We retrospectively included idiopathic pulmonary fibrosis (IPF) patients followed in our center (Marseille, France) between January 2020 and February 2023 who underwent diaphragmatic ultrasound. Our objectives were to describe the diaphragmatic function of IPFs compared to healthy controls and to correlate with clinical, functional, and lung density on CT-scan.

24 IPF patients and 157 controls were included. The diaphragmatic amplitude in IPF was increased at rest (median of 2.20 cm vs 1.88 cm on the right, p < 0.007, and 2.30 cm vs 1.91 cm on the left, p < 0.03, in IPF and controls respectively) and decreased in deep breathing (median of 4.85 cm vs 5.45 cm on the right, p < 0.009, and 5.10 cm vs 5.65 cm on the left, p < 0.046, in IPF and controls respectively). Diaphragmatic thickness was significantly reduced at rest on the right side (median of 1.75 mm vs 2.00 mm, p < 0.02, in IPF and controls respectively) and in deep breathing on both sides compared to controls (mean of 3.82 mm vs 4.15 mm on the right, p < 0.02, and 3.53 mm vs 3.94 mm, on the left, p < 0.009, in IPF and controls respectively). Diaphragmatic amplitude in deep breathing was moderate to strongly correlated with FVC, DLCO, and 6MWT and negatively correlated with the dyspnea and lung density on CT scan.

The diaphragmatic amplitude and thickness were impaired in IPF compared to controls. Diaphragmatic amplitude is the parameter best correlated with clinical, functional, and lung density criteria. Further studies are needed to determine if diaphragmatic amplitude can be a prognostic factor in IPF.

The diaphragm is considered the main muscle involved in breathing and also linked to trunk stabilization functions. Up to date, rehabilitative ultrasound imaging (RUSI) has been the most used technique to evaluate unilaterally the transcostal diaphragm thickness. Nevertheless, the inspiratory activity of both hemi-diaphragms is bilaterally performed at the same time, and its simultaneous evaluation with a thoracic orthosis could improve its assessment as well as its re-education with visual biofeedback of both hemi-diaphragms at the same time. The purpose was to evaluate the reliability and repeatability of simultaneous thickness measurements of both hemi-diaphragms bilaterally during normal breathing using a thoracic orthosis that allowed bilateral fixation of both right and left ultrasound probes.

The study was conducted in 46 healthy subjects, whose diaphragm thickness was measured bilaterally and simultaneously in the anterior axillary line during relaxed breathing with a designed thoracic orthosis and 2 ultrasound tools. Intra-examiner (same examiner), inter-examiner (2 examiners), intra-session (1 hour) and inter-session (1 week) reliability and repeatability between each pair of measurements of diaphragm muscle thickness were analyzed during normal breathing.

Reliability and repeatability for intra-session evaluations using the thoracic orthosis were excellent to evaluate simultaneous thickness of both hemi-diaphragms by bilateral probes fixation (intraclass correlation coefficient =0.919-0.997; standard error of measurement =0.002-0.007 cm; minimum detectable change =0.006-0.020 cm), without systematic errors (P>0.05) between each pair of measurements. Nevertheless, inter-session evaluations varied from good to excellent using the bilateral probes fixation (intraclass correlation coefficient =0.614-0.984; standard error of measurement =0.006-0.028 cm; minimum detectable change =0.017-0.079 cm), although some systematic errors were presented (P<0.05).

Good to excellent reliability and repeatability was shown for simultaneous thickness measurements of both hemi-diaphragms bilaterally during normal breathing. Despite systematic errors were presented for some inter-examiner assessments, the use of the thoracic orthosis that allowed bilateral fixation of ultrasound probes could be recommended for simultaneous hemi-diaphragms breathing re-education by visual biofeedback.

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.

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.

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.

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).

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.

The leading clinical feature of 5q-associated spinal muscular atrophy (SMA) is symmetric, proximal muscle weakness. Muscles involved in ventilation exhibit a specific pattern of denervation: intercostal muscles are severely atrophic, whereas the diaphragm muscle is less affected. The aim of this study was to investigate the involvement of diaphragmatic function by ultrasound imaging in adult patients with SMA and to quantify dynamics of diaphragmatic function during nusinersen treatment.

Diaphragmatic thickness, thickening, and excursion during quiet breathing were assessed in 24 adult patients with SMA type 2 and 3 by diaphragm ultrasound imaging before and during nusinersen treatment and were correlated with spirometric parameters.

Diaphragm thickness was not reduced, but increased in a remarkable proportion of patients, whereas diaphragm thickening and excursion were reduced in about 20% to 30% of nusinersen-naive, adult patients with SMA types 2 and 3. During 26 months of nusinersen treatment, diaphragm thickening fraction and excursion improved.

Diaphragm ultrasound imaging can provide disease- and treatment-relevant information that is not identified during routine clinical assessments and may therefore be a valuable complementary outcome measure.

Critically ill COVID-19 patients present long-term sequelae that affect their everyday life. This study aimed to describe the clinical and functional status of patients with severe COVID-19 pneumonia at 2-3 months post discharge from a Spanish critical care unit.

We collected retrospective data from 58 patients admitted to the critical care unit with diagnosis of severe respiratory failure due to COVID-19. Only patients who required invasive (IMV) or noninvasive ventilation (NIV) during their hospital stay were included. The following data were collected 2-3 months after hospital discharge: respiratory signs and symptoms, lung ultrasound (LUS) and diaphragm ultrasound images, blood test analysis, lung function parameters (spirometry and DLCO), exercise capacity (6 min walk test and sit-to-stand test), level of physical activity and health-related quality of life.

We found clinical symptoms and lung structural alterations in LUS images of 26 patients (48.1%). Those presenting LUS abnormalities had longer length of stay in hospital (p = 0.026), functional alterations in spirometry (p < 0.01) and decreased diaphragm excursion (p = 0.029). No significant alterations were observed in blood test analysis, exercise capacity, level of physical activity and health-related quality of life.

A significant part of the patients admitted to a critical care unit continue to present clinical symptoms, pulmonary morphological abnormalities, and lung function alterations 2-3 months post discharge. This study corroborates that assessing the functional status of the survivors is essential to monitor the evolution of pulmonary sequelae.

To numerically assess the significance of dextrose 5% in water (D5W) thermo-protection during radiofrequency ablation (RFA) of hepatocellular carcinomas (HCCs) located near the 'bare area of liver'.

This study utilises quasi-anatomical structures extracted from CT images. A multi-tine electrode, deployed inside the extracted organs and operated under temperature-controlled mode was used as the source of ablation. Geometrically, D5W was modelled around the 'bare area' and sandwiched between the liver and diaphragm. RFA at different sites relative to the 'bare area' was simulated to answer when to consider modelling D5W.

For targets near the edge of 'bare area' and at 0.5 mm gap (between the electrode and the 'bare area'), ignoring D5W and using ground conditions could result in underestimation of ablation volume by almost 25%. The importance of D5W becomes negligible for ablations near the centre of the 'bare area'.

Consideration of D5W during RFA of HCCs proximal to the 'bare area' can significantly influence the ablation outcome, especially when ablation is performed near the edge of the 'bare area'.

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.

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.

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.

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.

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.

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.

Sarcopenia and chronic obstructive pulmonary disease (COPD) are risk factors for postoperative pulmonary complications (PPCs). Preoperative inspiratory muscle weakness is also a risk factor for PPCs. Sarcopenia and COPD are often associated with inspiratory muscle weakness. Respiratory sarcopenia has been defined as the coexistence of whole-body sarcopenia and respiratory muscle weakness. We report our experience with preoperative pulmonary rehabilitation, including inspiratory muscle training (IMT), in a patient with lung cancer and comorbid respiratory sarcopenia and COPD.

A 73-year-old man with squamous cell lung cancer (cStage IA2) was hospitalized for pulmonary rehabilitation before lung resection. He had comorbid severe sarcopenia and COPD (GOLD stage III). He also had inspiratory muscle weakness and a thin diaphragm. We conducted IMT on the patient in addition to aerobic exercise and instruction regarding sputum expectoration for 2 weeks before the surgery. Consequently, his pulmonary function, respiratory muscle strength, and exercise capacity improved. Segmentectomy was performed using video-assisted thoracic surgery. No postoperative complications occurred.

IMT in a patient with lung cancer and comorbid respiratory sarcopenia and COPD resulted in improved respiratory muscle strength and pulmonary function. IMT may have reduced the risk of PPCs by strengthening the respiratory muscles and improving pulmonary function.

Ultrasonography of the diaphragm in the zone of apposition has become increasingly popular to evaluate muscle thickness and thickening fraction. However, measurements in this anatomical location are frequently hindered by factors that constrain physical accessibility or that alter diaphragm position. Therefore, other anatomical positions at the chest wall for transducer placement are used, but the variability in diaphragm thickness across the dome has not been systematically studied. The aim of this study was to evaluate anatomical variation of diaphragm thickness in 46 healthy volunteers on three ventrodorsal lines and two craniocaudal positions on these three lines. The intraclass correlation coefficient (ICC) for diaphragm thickness in the craniocaudal direction on the mid-axillary line was significantly higher than those on the posterior axillary and midclavicular lines, suggesting it had the lowest variability (ICC_midaxillary = .89, 95% confidence interval [CI]: 0.83-0.93, ICC_{posterior axillary} = 0.74, 95% CI: 0.62-0.85, ICC_{midclavicular} = 0.62, 95% CI: 0.43-0.47, p < 0.05). Average diaphragm thickness was comparable on the posterior axillary and midaxillary lines and substantially larger on the midclavicular line (1.24 mm [1.06-1.47], 1.27 mm [1.10-1.42] and 2.32 [1.97-2.70], p < 0.01). We conclude that the normal diaphragm has a large variability in thickness, especially in the ventrodorsal direction. Variability in craniocaudal position is the lowest at the midaxillary line, which therefore appears to be the preferred site for diaphragm thickness measurement.