Assessment of the reproducibility of the indirect ultrasound method of measuring diaphragm mobility

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

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

Diaphragm thickness and mobility elicited by two different modalities of inspiratory muscle loading in heart failure participants: A randomized crossover study

OBJECTIVES

To analyze diaphragmatic thickness, at end-inspiration and end-expiration, diaphragmatic thickening index and mobility via US under two different modalities of inspiratory muscle loading, in two different modalities of inspiratory muscle loading and different load intensities at full-vital capacity maneuvers and the relationship between diaphragmatic thickness with pulmonary function tests in participants with HF.

METHODS

This randomized crossover trial, enrolled with 17 HF subjects, evaluated diaphragm thickness (Tdi, mm), fractional thickness (TFdi, %), and mobility (mm) US during low and high intensities (30% and 60% of maximal inspiratory pressure-MIP) with two modalities of inspiratory muscle loading mechanical threshold loading (MTL) and tapered flow-resistive loading (TFRL).

RESULTS

Both MTL and TFRL produced a increase in Tdi, but only with high intensity loading compared to baseline-2.21 (0.26) vs. 2.68 (0.33) and 2.73 (0.44) mm; p = .01. TFdi was greater than baseline under all conditions, except during low intensity of TFRL. Diaphragm mobility was greater than baseline under all conditions, and high intensity of TFRL elicited greater mobility compared to all other conditions. Additionally, baseline Tdi was moderately correlated with pulmonary function tests.

CONCLUSIONS

MTL and TFRL modalities elicit similar increases in diaphragm thickness at loads, but only during high intensity loading it was greater than baseline. Diaphragm mobility was significantly greater than baseline under both loads and devices, and at high intensity compared to low intensity, although TFRL produced greater mobility compared to modalities of inspiratory muscle loading. There is an association between diaphragm thickness and pulmonary function tests.

Influence of mild pulmonary congestion on diaphragmatic mobility and activities of daily living in chronic kidney disease: An experimental and clinical study

BACKGROUND

Pulmonary congestion is a strong predictor of mortality and cardiovascular events in chronic kidney disease (CKD); however, the effects of the mild form on functionality have not yet been investigated. The objective of this study was to assess the influence of mild pulmonary congestion on diaphragmatic mobility (DM) and activities of daily living (ADL) in hemodialysis (HD) subjects, as well as compare ADL behavior on dialysis and non-dialysis days. In parallel, experimentally induce CKD in mice and analyze the resulting pulmonary and functional repercussions.

METHODS

Thirty subjects in HD underwent thoracic and abdominal ultrasonography, anthropometric assessment, lung and kidney function, respiratory muscle strength assessment and symptoms analysis. To measure ADL a triaxial accelerometer was used over seven consecutive days. Twenty male mice were randomized in Control and CKD group. Thoracic ultrasonography, TNF-α analysis in kidney and lung tissue, exploratory behavior and functionality assessments were performed.

RESULTS

Mild pulmonary congestion caused a 26.1% decline in DM (R²=.261; P=.004) and 20% reduction in walking time (R²=.200; P=.01), indicating decreases of 2.23mm and 1.54min, respectively, for every unit increase in lung comet-tails. Regarding ADL, subjects exhibited statistically significant differences for standing (P=.002), walking (P=.034) and active time (P=.002), and number of steps taken (P=.01) on days with and without HD. In the experimental model, CKD resulted in increased levels of TNF-α on kidneys (P=.037) and lungs (P=.02), attenuation of exploratory behavior (P=.01) and significant decrease in traveled distance (P=.034). Thoracic ultrasonography of CKD mice showed presence of B-lines.

CONCLUSION

The mild pulmonary congestion reduced DM and walking time in subjects undergoing HD. Individuals were less active on dialysis days. Furthermore, the experimental model implies that the presence of pulmonary congestion and inflammation may play a decisive role in the low physical and exploratory performance of CKD mice.

Ultrasonography Comparison of Diaphragm Morphological Structure and Function in Young and Middle-Aged Subjects with and without Non-Specific Chronic Low Back Pain: A Case-Control Study

Background

It is reported that impaired postural control in patients with non-specific chronic low back pain (NCLBP) was associated with "core" trunk muscle incoordination. However, as the diaphragm is an important component of the "core" deep trunk muscle group, we still know little about the potential relationship between diaphragm dysfunction and NCLBP.

Objectives

This case-control study is intended to investigate the changes of diaphragm morphological structure and function in young and middle-aged subjects with and without NCLBP by ultrasound evaluation and its possible validity in predicating the occurrence of NCLBP.

Methods

31 subjects with NCLBP (NCLBP group) and 32 matched healthy controls (HC group) were enrolled in this study. The diaphragm thickness at the end of inspiration (T ^ins) or expiration (T ^exp) during deep breathing was measured through B-mode ultrasound, and the diaphragm excursion (T ^exc) was estimated at deep breathing through M-mode ultrasound. The diaphragm thickness change rate (T ^rate) was calculated by the formula: T ^rate=(T ^ins - T ^exp)/T ^exp × 100%.

Results

Compared with the HC group, the NCLBP group had a significant smaller degree of T^ins (t = -3.90, P < 0.001), T ^exp (Z = -2.79, P=0.005), and T ^rate (t = -2.03, P=0.047). However, there was no statistical difference in T ^exc between the two groups (t = -1.42, P=0.161). The binary logistic regression analysis indicated that T ^rate (OR = 16.038, P=0.014) and T ^exp (OR = 7.714, P=0.004) were potential risk factors for the occurrence of NCLBP.

Conclusions

The diaphragm morphological structure and function were changed in young and middle-aged subjects with NCLBP, while the diaphragm thickness change rate (T ^rate) and diaphragm thickness at the end of expiration (T ^exp) may be conductive to the occurrence of NCLBP. Furthermore, these findings may suggest that abnormal diaphragm reeducation is necessary for the rehabilitation of patients with NCLBP.

Evaluation of diaphragm thickening by diaphragm ultrasonography: a reproducibility and a repeatability study

PURPOSE

We have focused on the two-dimensional (B-mode) and the time-motion (M-mode) analysis of the zone of apposition to determine the reliability of diaphragm ultrasonography in the clinical environment.

METHODS

Ten healthy volunteers were enrolled and studied by three operators with different skills in ultrasonography. For every volunteer, each operator acquired three images of the diaphragm for each side, both in B-mode and in M-mode. Then a fourth operator calculated the thickening fraction (TF), by means of the formula TF = (TEI - TEE)/TEE (TEI is the thickness at end inspiration and TEE the thickness at end expiration). Afterwards, intraclass correlation coefficients (ICCs) were computed on TF to establish reproducibility and repeatability both in the B- and M-modes. A Coefficient of Repeatability or repeatability (CR) ≤ 0.3 was considered acceptable.

RESULTS

Both B-mode (CRs 0.16-0.26) and M-mode (CRs 0.10-0.15) were sufficiently repeatable to assess TF, except for the less experienced operator (CRs B-Mode 0.20-0.32). Reproducibility was moderate to good between operators with CRs much narrower for the M-Mode (0.13-0.14).

CONCLUSIONS

The results of our study have shown that diaphragm ultrasound is repeatable and reproducible when carried out by a radiologist or an intensivist with a basic curriculum in ultrasonography. The method is more accurate when using the M-mode for less experienced operators, and in this case, repeatability and reproducibility are not sufficient to make clinical decisions. No TF value lower than 36% was obtained using both techniques. This suggests the existence of a cut-off value that could be used as an initial tool to discriminate healthy subjects from those affected by diaphragmatic dysfunction.

CLINICAL TRIAL REGISTRATION

EUDRACT 2015-004635-12.

Peri-operative diaphragm ultrasound as a new method of recognizing post-operative residual curarization

Background

This study sought to evaluate the diagnostic accuracy of peri-operative diaphragm ultrasound in assessing post-operative residual curarization (PORC).

Methods

Patients undergoing non-thoracic and non-abdominal surgery under general anaesthesia were enrolled from July 2019 to October 2019 at Peking Union Medical College Hospital. A train-of-four ratio (TOFr) lower than 0.9 was considered as the gold standard for PORC. Diaphragm ultrasound parameters included diaphragmatic excursion (DE) and diaphragm thickening fraction (DTF) during quiet breathing (QB) and deep breathing (DB). The diaphragm excursion fraction (DEF) was calculated as the DE-QB divided by the DE-DB. The diaphragm excursion difference (DED) was defined as DE-DB minus DE-QB. Receiver operating characteristic curve analysis was used to determine the cut-off values of ultrasound parameters for the prediction of PORC.

Results

In total, 75 patients were included, with a PORC incidence of 54.6%. The DE-DB and DED were positively correlated with the TOFr, while the DEF was negatively correlated with the TOFr. The DE-DB cut-off value for predicting PORC was 3.88 cm, with a sensitivity of 85.4% (95% confidence interval [CI]: 70.1–93.9%), specificity of 64.7% (95% CI: 46.4–79.7%), positive likelihood ratio of 2.42 (95% CI 1.5–3.9), and negative likelihood ratio of 0.23 (95% CI: 0.1–0.5). The DED cut-off value was 1.5 cm, with a specificity of 94.2% (95% CI: 80.3–99.3%), sensitivity of 63.4% (95% CI: 46.9–77.9%), positive likelihood ratio of 10.78 (95% CI: 2.8–42.2), and negative likelihood ratio of 0.39 (95% CI: 0.3–0.6).

Conclusions

Peri-operative diaphragm ultrasound may be an additional method aiding the recognition of PORC, with DED having high specificity.

Pneumothorax: Classification and Etiology

Pneumothorax is a common problem worldwide. Pneumothorax develops secondary to diverse aetiologies; in many cases, there may be no recognizable lung abnormality. The pathogenetic mechanism(s) causing spontaneous pneumothorax may be related to an interplay between lung-related abnormalities and environmental factors such as smoking. Tobacco smoking is a major risk factor for primary spontaneous pneumothorax; chronic obstructive pulmonary disease is most frequently associated with secondary spontaneous pneumothorax. This review article provides an overview of the historical perspective, epidemiology, classification, and aetiology of pneumothorax. It also aims to highlight current knowledge and understanding of underlying risks and pathophysiological mechanisms in pneumothorax development.

Mobility impact and methods of diaphragm monitoring in patients with chronic obstructive pulmonary disease: a systematic review

The objectives of the study were to identify the factors that limit diaphragmatic mobility and evaluate the therapeutic results of the monitoring methods previously used in patients with chronic obstructive pulmonary disease. The PubMed, Web of Science, Scopus, and LILACS databases were used. A gray literature search was conducted with Google scholar. PRISMA was used, and the bias risk analysis adapted from the Cochrane Handbook for clinical trials and, for other studies, the Downs and Black checklist were used. Twenty-five articles were included in the qualitative synthesis analysis on physiotherapeutic techniques and diaphragmatic mobility. Eight clinical trials indicated satisfactory domains, and on the Downs and Black scale, 17 cohort studies were evaluated to have an acceptable score. Different conditions must be observed; for example, for postoperative assessments the supine position is suggested to be the most appropriate position to verify diaphragm excursion, although it has been shown to be associated with difficulty of restriction and matching in samples. Therefore, we identified the need for contemporary adjustments and strategies that used imaging instruments, preferably in the dorsal position. Therapeutic evidence on the association between the instrumental method and diaphragmatic mobility can be controversial. The ultrasound measurements indicated some relevance for different analyses, for pulmonary hyperinflation as well as diaphragm thickness and mobilization, in COPD patients. In particular, the study suggests that the ultrasound technique with B-mode for analysis and M-mode for diaphragmatic excursion be used with a 2 - 5 MHz with the patient in the supine position. However, the methods used to monitor diaphragm excursion should be adapted to the conditions of the patients, and additional investigations of their characteristics should be performed. More selective inclusion criteria and better matching in the samples are very important. In addition, more narrow age, sex and weight categories are important, especially in patients with chronic obstructive pulmonary disease.

Lipoabdominoplasty: repercussions for diaphragmatic mobility and lung function in healthy women

Objective:

To evaluate the impact of lipoabdominoplasty on diaphragmatic mobility (DM) and lung function in healthy women.

Methods:

This was a prospective cohort study using high-resolution ultrasound and forced spirometry to assess DM and lung function, respectively, prior to lipoabdominoplasty, as well as on postoperative day (POD) 10 and POD 30. DM was measured under two conditions: during tidal volume breathing and during a VC maneuver.

Results:

The sample consisted of 20 women, with a mean age of 39.85 ± 7.52 years and a mean body mass index of 26.21 ± 2.0 kg/m². Comparing the preoperative and postoperative periods, we found that DM and lung function values were significantly lower after lipoabdominoplasty, the mean DM on POD 10 being 17% and 15% lower during tidal volume breathing and during the VC maneuver, respectively, in comparison with the preoperative mean (p = 0.009 and p < 0.001, respectively). In addition, FEV₁, FVC, and PEF were significantly lower on POD 10 than in the preoperative period (p = 0.046, p = 0.002, and p < 0.001, respectively), returning to preoperative values by POD 30.

Conclusions:

Lipoabdominoplasty appears to have negative short-term repercussions for DM and lung function in healthy women. However, lung function and DM are both apparently restored to preoperative conditions by POD 30. (ClinicalTrials.gov identifier: NCT02762526 [http://www.clinicaltrials.gov/])

Comparison of diaphragmatic mobility between COPD patients with and without thoracic hyperkyphosis: a cross-sectional study

Objective:

To compare diaphragmatic mobility, lung function, and respiratory muscle strength between COPD patients with and without thoracic hyperkyphosis; to determine the relationship of thoracic kyphosis angle with diaphragmatic mobility, lung function, and respiratory muscle strength in COPD patients; and to compare diaphragmatic mobility and thoracic kyphosis between male and female patients with COPD.

Methods:

Participants underwent anthropometry, spirometry, thoracic kyphosis measurement, and evaluation of diaphragmatic mobility.

Results:

A total of 34 patients with COPD participated in the study. Diaphragmatic mobility was significantly lower in the group of COPD patients with thoracic hyperkyphosis than in that of those without it (p = 0.002). There were no statistically significant differences between the two groups of COPD patients regarding lung function or respiratory muscle strength variables. There was a significant negative correlation between thoracic kyphosis angle and diaphragmatic mobility (r = −0.47; p = 0.005). In the sample as a whole, there were statistically significant differences between males and females regarding body weight (p = 0.011), height (p < 0.001), and thoracic kyphosis angle (p = 0.036); however, there were no significant differences in diaphragmatic mobility between males and females (p = 0.210).

Conclusions:

Diaphragmatic mobility is lower in COPD patients with thoracic hyperkyphosis than in those without it. There is a negative correlation between thoracic kyphosis angle and diaphragmatic mobility. In comparison with male patients with COPD, female patients with COPD have a significantly increased thoracic kyphosis angle.

Validity and reliability of assessing diaphragmatic mobility by area on X-rays of healthy subjects

OBJECTIVE

To investigate the concurrent validity, as well as the intra- and inter-rater reliability, of assessing diaphragmatic mobility by area (DMarea) on chest X-rays of healthy adults.

METHODS

We evaluated anthropometric parameters, pulmonary function, and diaphragmatic mobility in 43 participants. Two observers (rater A and rater B) determined diaphragmatic mobility at two time points. We used Pearson's correlation coefficient to evaluate the correlation between DMarea and the assessment of diaphragmatic mobility by distance (DMdist). To evaluate intra- and inter-rater reliability, we used the intraclass correlation coefficient (ICC [2,1]), 95% CI, and Bland-Altman analysis.

RESULTS

A significant correlation was found between the DMarea and DMdist methods (r = 0.743; p < 0.0001). For DMarea, the intra-rater reliability was found to be quite high for the right hemidiaphragm (RHD)-ICC (2,1) = 0.92 (95% CI: 0.86-0.95) for rater A and ICC (2,1) = 0.90 (95% CI: 0.84-0.94) for rater B-and the left hemidiaphragm (LHD)-ICC (2,1) = 0.96 (95% CI: 0.93-0.97) for rater A and ICC (2,1) = 0.91 (95% CI: 0.81-0.95) for rater B-(p < 0.0001 for all). Also for DMarea, the inter-rater reliability was found to be quite high for the first and second evaluations of the RHD-ICC (2,1) = 0.99 (95% CI: 0.98-0.99) and ICC (2,1) = 0.95 (95% CI: 0.86-0.97), respectively-and the LHD-ICC (2,1) = 0.99 (95% CI: 0.98-0.99) and ICC (2,1) = 0.94 (95% CI: 0.87-0.97)-(p < 0.0001 for both). The Bland-Altman analysis showed good agreement between the mobility of the RHD and that of the LHD.

CONCLUSIONS

The DMarea method proved to be a valid, reliable measure of diaphragmatic mobility.

Mobilidade diafragmática direita e esquerda em indivíduos saudáveis e na doença pulmonar obstrutiva crônica

RESUMO Avaliar o músculo diafragma é importante para verificar suas possíveis alterações ou disfunções. Existem várias formas de avaliar a mobilidade diafragmática, mas poucos estudos que comparam a mobilidade do hemidiafragma direito com o esquerdo. O objetivo deste estudo é avaliar se existem diferenças entre a mobilidade diafragmática das hemicúpulas direita e esquerda em indivíduos saudáveis e em indivíduos com Doença Pulmonar Obstrutiva Crônica (DOCP), bem como comparar a mobilidade diafragmática entre homens e mulheres, e entre pacientes saudáveis e com DPOC. Foram avaliados 40 indivíduos saudáveis e 40 indivíduos com diagnóstico clínico de DPOC. Utilizaram-se os parâmetros antropométricos, cardiopulmonares e avaliação da mobilidade diafragmática pelo método radiográfico. Os dados foram analisados estatisticamente e tratados com análise descritiva (média e desvio-padrão) e análise inferencial. Para comparar a mobilidade das hemicúpulas diafragmáticas direita e esquerda, utilizou-se o teste t pareado. O nível de significância adotado para o tratamento estatístico foi de 5% (p<0,05). Não houve diferença da mobilidade diafragmática tanto do lado direito quanto do lado esquerdo nos indivíduos saudáveis (p=0,45) e nos indivíduos com DPOC (p=0,77), assim como não houve diferenças quando os grupos foram separados por sexo. Foi encontrada uma diferença importante comparando tanto a mobilidade diafragmática do lado direito quanto do lado esquerdo entre indivíduos saudáveis e DPOC (p<0,001). Concluiu-se que a mobilidade diafragmática das hemicúpulas direita e esquerda em indivíduos saudáveis e em indivíduos com DPOC é a mesma. Não há diferença da mobilidade entre homens e mulheres. A mobilidade diafragmática é reduzida em paciente com DPOC.

Use of thoracic ultrasound by physiotherapists: a scoping review of the literature

BACKGROUND

Use of diagnostic thoracic ultrasound (TUS) in medical professions to examine the pleura, lung parenchyma and diaphragm is gaining in popularity, however the ways in which physiotherapists are using TUS is unclear.

OBJECTIVE

The aim of this scoping review is to gain an understanding of the emerging evidence base surrounding physiotherapy use of TUS to inform research and clinical practice.

DATA SOURCES

A systematic search was conducted of the following databases: Cochrane, EPPI centre, PROSPERO, Medline, CINAHL, AMED, EMBASE, HMIC, and BNI.

STUDY SELECTION

Inclusion criteria: primary research reporting the use of diagnostic TUS; a physiotherapist as part of the study design or as the chief investigator; published in English.

SYNTHESIS METHODS

Data regarding demographics, design, type of conditions and anatomical structures investigated and profession leading the TUS of included papers were compiled in a tabular format.

RESULTS

Of the 26 included papers, nine studied healthy participants, four studied COPD and four studied critical care patients. Most papers (n=23) involved scanning the diaphragm. In eight studies the physiotherapist operated the TUS.

LIMITATIONS

The paper selection process was performed by one author; with no cross-checking by another individual.

CONCLUSION

Use of TUS by physiotherapists is an emerging area in both diaphragm and lung diagnostics. A wide range of patient populations may benefit from physiotherapists using TUS. Papers in this review are heterogeneous making any generalisability difficult but does show its potential for varied uses. TUS is an innovative skill in the hands of physiotherapists, but more research is needed.

Validity and reliability of fluoroscopy for digital radiography: a new way to evaluate diaphragmatic mobility

Background

Fluoroscopy is considered the most accurate method to evaluate the diaphragm, yet most existing methods for measuring diaphragmatic mobility using fluoroscopy are complex. To assess the validity and reliability of a new evaluation method of diaphragmatic motion using fluoroscopy by digital radiography of healthy adults.

Methods

Twenty-six adults were evaluated, according to the parameters: anthropometry and pulmonary function test. The evaluation of diaphragm mobility by means of fluoroscopy by digital radiography method was randomly conducted by two raters (A and B). The Pearson correlation coefficient and the intraclass correlation coefficient (ICC) were used to assess the concurrent validity. The inter-rater and intra-rater reliability of the measurement of diaphragmatic motion was determined using ICC and a confidence interval of 95%.

Results

There was a relationship in the assessment of the concurrent validity. There was good inter-rater reliability for right hemidiaphragm mobility and moderate reliability for left hemidiaphragm in the first assessment. In the second assessment, there was good reliability for the mobility of both hemidiaphragms. There was good intra-rater reliability in the mobility of both hemidiaphragms for raters A and B.

Conclusion

The evaluation of diaphragmatic motion using fluoroscopy by digital radiography proved to be a valid and reliable method of healthy adults.

Reproducibility of the SPI-US protocol for ultrasound diameter measurements of the Posterior Circumflex Humeral Artery and Deep Brachial Artery: an inter-rater reliability study

OBJECTIVES

Elite overhead athletes are at risk of posterior circumflex humeral artery (PCHA) degeneration, aneurysm formation and thrombosis. Identification of the proximal PCHA and the nearby originating deep brachial artery (DBA) can be a challenge, even among experienced sonographers. The aim of this study was to assess the accuracy and precision of a newly designed standardized ultrasound (US) protocol (SPI-US) for assessment of the PCHA and DBA.

METHODS

Two experienced sonographers determined diameters of the PCHA and DBA using the SPI-US protocol. Inter-observer agreement was evaluated using intra-class correlation coefficient (ICC), standard error of measurement (SEM), minimal detectable change (MDC), Bland-Altman (BA) analysis, and variance component (VARCOMP) analysis.

RESULTS

Thirty-three healthy volunteers participated. The ICC for diameter measurement of the PCHA and DBA were 0.70 (95 %CI 0.50-0.83) and 0.60 (95 %CI 0.30-0.80), respectively. The SEM for the PCHA and DBA was 0.32 mm and 0.29 mm and MDC was 0.90 mm and 0.80 mm, respectively. The BA and VARCOMP analyses showed no systematic and only marginal sonographer bias.

CONCLUSIONS

The SPI-US protocol is accurate and precise for PCHA and DBA diameter assessment in cases where they originate from the axillary artery. PCHA and DBA diameter measurements are sonographer-independent using the SPI-US-protocol.

KEY POINTS

• PCHA & DBA diameter assessment is accurate and reliable using the SPI-US protocol • PCHA & DBA diameter measurements are sonographer-independent using the SPI-US protocol • The SPI-US protocol minimal detectable change is 0.90 mm for PCHA diameter measurement • This minimal detectable change enables detection of PCHA aneurysms • First step towards international periodic surveillance of athletes at risk of PCHA-injury.