Background: Although diaphragmatic motion is readily studied by ultrasonography, the procedure remains poorly codified. The aim of this
prospective study was to determine the reference values for ...diaphragmatic motion as recorded by M-mode ultrasonography.
Methods: Two hundred ten healthy adult subjects (150 men, 60 women) were investigated. Both sides of the posterior diaphragm were
identified, and M-mode was used to display the movement of the anatomical structures. Examinations were performed during quiet
breathing, voluntary sniffing, and deep breathing. Diaphragmatic excursions were measured from the M-mode sonographic images.
In addition, the reproducibility (inter- and intra-observer) was assessed.
Results: Right and left diaphragmatic motions were successfully assessed during quiet breathing in all subjects. During voluntary
sniffing, the measurement was always possible on the right side, and in 208 of 210 volunteers, on the left side. During deep
breathing, an obscuration of the diaphragm by the descending lung was noted in subjects with marked diaphragmatic excursion.
Consequently, right diaphragmatic excursion could be measured in 195 of 210 subjects, and left diaphragmatic excursion in
only 45 subjects. Finally, normal values of both diaphragmatic excursions were determined. Since the excursions were larger
in men than in women, the gender should be taken into account. The lower limit values were close to 0.9 cm for women and 1
cm for men during quiet breathing, 1.6 cm for women and 1.8 cm for men during voluntary sniffing, and 3.7 cm for women and
4.7 cm for men during deep breathing.
Conclusions: We demonstrated that M-mode ultrasonography is a reproducible method for assessing hemidiaphragmatic movement.
This article reports the various methods used to assess diaphragmatic function by ultrasonography. The excursions of the two hemidiaphragms can be measured using two-dimensional or M-mode ...ultrasonography, during respiratory maneuvers such as quiet breathing, voluntary sniffing and deep inspiration. On the zone of apposition to the rib cage for both hemidiaphragms, it is possible to measure the thickness on expiration and during deep breathing to assess the percentage of thickening during inspiration. These two approaches make it possible to assess the quality of the diaphragmatic function and the diagnosis of diaphragmatic paralysis or dysfunction. These methods are particularly useful in circumstances where there is a high risk of phrenic nerve injury or in diseases affecting the contractility or the motion of the diaphragm such as neuro-muscular diseases. Recent methods such as speckle tracking imaging and ultrasound shear wave elastography should provide more detailed information for better assessment of diaphragmatic function.
Rapid response teams are intended to improve early diagnosis and intervention in ward patients who develop acute respiratory or circulatory failure. A management protocol including the use of a ...handheld ultrasound device for immediate point-of-care ultrasound (POCUS) examination at the bedside may improve team performance. The main objective of the study was to assess the impact of implementing such a POCUS-guided management on the proportion of adequate immediate diagnoses in two groups. Secondary endpoints included time to treatment and patient outcomes.
A prospective, observational, controlled study was conducted in a single university hospital. Two teams alternated every other day for managing in-hospital ward patients developing acute respiratory and/or circulatory failures. Only one of the team used an ultrasound device (POCUS group).
We included 165 patients (POCUS group 83, control group 82). Proportion of adequate immediate diagnoses was 94% in the POCUS group and 80% in the control group (p = 0.009). Time to first treatment/intervention was shorter in the POCUS group (15 10-25 min vs. 34 15-40 min, p < 0.001). In-hospital mortality rates were 17% in the POCUS group and 35% in the control group (p = 0.007), but this difference was not confirmed in the propensity score sample (29% vs. 34%, p = 0.53).
Our study suggests that protocolized use of a handheld POCUS device at the bedside in the ward may improve the proportion of adequate diagnosis, the time to initial treatment and perhaps also survival of ward patients developing acute respiratory or circulatory failure. Clinical Trial Registration NCT02967809. Registered 18 November 2016, https://clinicaltrials.gov/ct2/show/NCT02967809 .
Diaphragm ultrasonography is rapidly evolving in both critical care and research. Nevertheless, methodologically robust guidelines on its methodology and acquiring expertise do not, or only ...partially, exist. Therefore, we set out to provide consensus-based statements towards a universal measurement protocol for diaphragm ultrasonography and establish key areas for research.
To formulate a robust expert consensus statement, between November 2020 and May 2021, a two-round, anonymous and online survey-based Delphi study among experts in the field was performed. Based on the literature review, the following domains were chosen: "Anatomy and physiology", "Transducer Settings", "Ventilator Impact", "Learning and expertise", "Daily practice" and "Future directions". Agreement of ≥ 68% (≥ 10 panelists) was needed to reach consensus on a question.
Of 18 panelists invited, 14 agreed to participate in the survey. After two rounds, the survey included 117 questions of which 42 questions were designed to collect arguments and opinions and 75 questions aimed at reaching consensus. Of these, 46 (61%) consensus was reached. In both rounds, the response rate was 100%. Among others, there was agreement on measuring thickness between the pleura and peritoneum, using > 10% decrease in thickness as cut-off for atrophy and using 40 examinations as minimum training to use diaphragm ultrasonography in clinical practice. In addition, key areas for research were established.
This expert consensus statement presents the first set of consensus-based statements on diaphragm ultrasonography methodology. They serve to ensure high-quality and homogenous measurements in daily clinical practice and in research. In addition, important gaps in current knowledge and thereby key areas for research are established. Trial registration The study was pre-registered on the Open Science Framework with registration digital object identifier https://doi.org/10.17605/OSF.IO/HM8UG .
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.
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Chest ultrasonography has proven to be useful in the diagnosis of diaphragm dysfunction. The aim of the present study was to determine the normal values of the motion of both hemidiaphragms recorded ...by M-mode ultrasonography. Healthy volunteers were studied while in a seated position. Diaphragmatic excursions and diaphragm profiles were measured during quiet breathing, voluntary sniffing and deep breathing. Diaphragmatic excursions were assessed by M-mode ultrasonography, using an approach perpendicular to the posterior part of the diaphragm. Anatomical M-mode was used for the recording of the complete excursion during deep breathing. The study included 270 men and 140 women. The diaphragmatic motions during quiet breathing and voluntary sniffing were successfully recorded in all of the participants. The use of anatomical M-mode was particularly suitable for measurement of the entire diaphragmatic excursion during deep breathing. The statistical analysis showed that the diaphragmatic excursions were larger in men compared to women, supporting the determination of normal values based on sex. The lower and upper limits of normal excursion were determined for men and women for both hemidiaphragms during the three manoeuvres that were investigated. The lower limits of normal diaphragmatic excursions during deep breathing should be used to detect diaphragmatic hypokinesia,
3.3 and 3.2 cm in women and 4.1 and 4.2 cm in men for the right and the left sides, respectively. The normal values of the diaphragmatic motion and the lower and upper limits of normal excursion can be used by clinicians to detect diaphragmatic dysfunction.
On one side, decompression sickness (DCS) with neurological disorders lead to a reshuffle of the fecal metabolome from rat caecum. On the other side, there is high inter-individual variability in ...terms of occurrence of DCS. One could wonder whether the fecal metabolome could be linked to the DCS-susceptibility. We decided to study male and female rats selected for their resistance to decompression sickness, and we hypothesize a strong impregnation concerning the fecal metabolome. The aim is to verify whether the rats resistant to the accident have a fecal metabolomic signature different from the stem generations sensitive to DCS. 39 DCS-resistant animals (21 females and 18 males), aged 14 weeks, were compared to 18 age-matched standard Wistar rats (10 females and 8 males), i.e., the same as those we used for the founding stock. Conventional and ChemRICH approaches helped the metabolomic interpretation of the 226 chemical compounds analyzed in the cecal content. Statistical analysis shows a panel of 81 compounds whose expression had changed following the selection of rats based on their resistance to DCS. 63 compounds are sex related. 39 are in common. This study shows the spectral fingerprint of the fecal metabolome from the caecum of a strain of rats resistant to decompression sickness. This study also confirms a difference linked to sex in the metabolome of non-selected rats, which disappear with selective breeding. Results suggest hormonal and energetic reshuffle, including steroids sugars or antibiotic compounds, whether in the host or in the microbial community.
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Abstract
Introduction
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.
Methods
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.
Results
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.
Conclusion
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.
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Background An association was reported between the left ventricular longitudinal strain (LV-LS) and preload. LV-LS reflects the left cardiac function curve as it is the ratio of shortening over ...diastolic dimension. The aim of this study was to determine the sensitivity and specificity of LV-LS variations after a passive leg raising (PLR) maneuver to predict fluid responsiveness in intensive care unit (ICU) patients with acute circulatory failure (ACF). Methods Patients with ACF were prospectively included. Preload-dependency was defined as a velocity time integral (VTI) variation greater than 10% between baseline (T0) and PLR (T1), distinguishing the preload-dependent (PLD+) group and the preload-independent (PLD-) group. A 7-cycles, 4-chamber echocardiography loop was registered at T0 and T1, and strain analysis was performed off-line by a blind clinician. A general linear model for repeated measures was used to compare the LV-LS variation (T0 to T1) between the two groups. Results From June 2018 to August 2019, 60 patients (PLD+ = 33, PLD- = 27) were consecutively enrolled. The VTI variations after PLR were +21% (±8) in the PLD+ group and -1% (±7) in the PLD- group (p<0.01). Mean baseline LV-LS was -11.3% (±4.2) in the PLD+ group and -13.0% (±4.2) in the PLD- group (p = 0.12). LV-LS increased in the whole population after PLR +16.0% (±4.0) (p = 0.04). The LV-LS variations after PLR were +19.0% (±31) (p = 0.05) in the PLD+ group and +11.0% (±38) (p = 0.25) in the PLD- group, with no significant difference between the two groups (p = 0.08). The area under the curve for the LV-LS variations between T0 and T1 was 0.63 0.48-0.77. Conclusion Our study confirms that LV-LS is load-dependent; however, the variations in LV-LS after PLR is not a discriminating criterion to predict fluid responsiveness of ICU patients with ACF in this cohort.
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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.
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