Left hemidiaphragmatic mobility: assessment with ultrasonographic measurement of the craniocaudal displacement of the splenic hilum and the inferior pole of the spleen

The Role of Ultrasonography in the Process of Weaning from Mechanical Ventilation in Critically Ill Patients

Weaning patients from mechanical ventilation (MV) is a complex process that may result in either success or failure. The use of ultrasound at the bedside to assess organs may help to identify the underlying mechanisms that could lead to weaning failure and enable proactive measures to minimize extubation failure. Moreover, ultrasound could be used to accurately identify pulmonary diseases, which may be responsive to respiratory physiotherapy, as well as monitor the effectiveness of physiotherapists' interventions. This article provides a comprehensive review of the role of ultrasonography during the weaning process in critically ill patients.

Reliability and validity of ultrasonography in evaluating the thickness, excursion, stiffness, and strain rate of respiratory muscles in non-hospitalized individuals: a systematic review

OBJECTIVE

To summarize the reliability and validity of ultrasonography in evaluating the stiffness, excursion, stiffness, or strain rate of diaphragm, intercostals and abdominal muscles in healthy or non-hospitalized individuals.

LITERATURE SEARCH

PubMed, Embase, SPORTDiscus, CINAHL and Cochrane Library were searched from inception to May 30, 2022.

STUDY SELECTION CRITERIA

Case-control, cross-sectional, and longitudinal studies were included if they investigated the reliability or validity of various ultrasonography technologies (e.g., brightness-mode, motion-mode, shear wave elastography) in measuring the thickness, excursion, stiffness, or strain rate of any respiratory muscles.

DATA SYNTHESIS

Relevant data were summarized based on healthy and different patient populations. The methodological quality by different checklist depending on study design. The quality of evidence of each psychometric property was graded by the Grading of Recommendations, Assessment, Development and Evaluations, respectively.

RESULTS

This review included 24 studies with 787 healthy or non-hospitalized individuals (e.g., lower back pain (LBP), adolescent idiopathic scoliosis (AIS), and chronic obstructive pulmonary disease (COPD)). Both inspiratory (diaphragm and intercostal muscles) and expiratory muscles (abdominal muscles) were investigated. Moderate-quality evidence supported sufficient (intra-class correlation coefficient > 0.7) within-day intra-rater reliability of B-mode ultrasonography in measuring right diaphragmatic thickness among people with LBP, sufficient between-day intra-rater reliability of M-mode ultrasonography in measuring right diaphragmatic excursion in non-hospitalized individuals. The quality of evidence for all other measurement properties in various populations was low or very low. High-quality evidence supported sufficient positive correlations between diaphragm excursion and forced expiratory volume in the first second or forced vital capacity (r >  = 0.3) in healthy individuals.

CONCLUSIONS

Despite the reported sufficient reliability and validity of using ultrasonography to assess the thickness, excursion, stiffness, and strain rate of respiratory muscles in non-hospitalized individuals, further large-scale studies are warranted to improve the quality of evidence regarding using ultrasonography for these measurements in clinical practice. Researchers should establish their own reliability before using various types of ultrasonography to evaluate respiratory muscle functions.

TRIAL REGISTRATION

PROSPERO NO. CRD42022322945.

Ultrasound imaging of diaphragmatic motion

The diaphragm is the key muscle of respiration, especially in infants. Diaphragmatic dysfunction and paralysis can have significant implications for medical management and treatment, and they can be challenging to diagnose by clinical parameters alone. Multiple imaging modalities are useful for assessing the diaphragm, but US - specifically M-mode US - offers several distinct advantages and few limitations compared to fluoroscopy, radiography, CT and MRI. The purpose of this manuscript is to discuss the pathophysiology of the diaphragm, review common indications for dynamic diaphragmatic US, describe optimal imaging technique, and discuss how to avoid imaging pitfalls.

Ultrasound evaluation of diaphragm motion in BAG-3 myofibrillar myopathy: A case report

RATIONALE

Mutations in Bcl-2-associated athanogene-3 (BAG-3) can cause a rare subtype of myofibrillar myopathies (MFMs), characterized by progressive muscle weakness, cardiomyopathy, and severe respiratory insufficiency in childhood. Little is known about diaphragmatic function in BAG-3 MFM. To our knowledge, this is the first case report of detailed evaluation of diaphragmatic function with ultrasound in BAG-3 MFM.

PATIENT CONCERN

We describe the case of a 15-year-old girl who complained of fever and shortness of breath. Diaphragmatic sonography revealed bilateral diaphragmatic paralysis. Shortness of breath progressed to respiratory failure approximately 3 months later.

DIAGNOSIS

A neurologist was consulted and genetic sequencing identified a p.Pro209Leu mutation in BAG-3, yielding diagnosis of BAG-3 MFM leading to bilateral diaphragmatic paralysis.

INTERVENTIONS

Respiratory muscle training and long-term mechanical ventilation.

OUTCOMES

It is quite unfortunate for this patient to have a poor prognosis due to the lack of effective treatment for this genetic disorder.

LESSONS

This case provides more clinical information for this rare disease which may cause severe diaphragm pathological damage leading to respiratory failure in BAG3 MFM and a future study with a systematic evaluation of a greater number of patients will be necessary to characterize this population.

Assessment of diaphragmatic function by ultrasonography: Current approach and perspectives

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.

Respiratory muscle ultrasonography: methodology, basic and advanced principles and clinical applications in ICU and ED patients-a narrative review

Respiratory muscle ultrasound is used to evaluate the anatomy and function of the respiratory muscle pump. It is a safe, repeatable, accurate, and non-invasive bedside technique that can be successfully applied in different settings, including general intensive care and the emergency department. Mastery of this technique allows the intensivist to rapidly diagnose and assess respiratory muscle dysfunction in critically ill patients and in patients with unexplained dyspnea. Furthermore, it can be used to assess patient-ventilator interaction and weaning failure in critically ill patients. This paper provides an overview of the basic and advanced principles underlying respiratory muscle ultrasound with an emphasis on the diaphragm. We review different ultrasound techniques useful for monitoring of the respiratory muscle pump and possible therapeutic consequences. Ideally, respiratory muscle ultrasound is used in conjunction with other components of critical care ultrasound to obtain a comprehensive evaluation of the critically ill patient. We propose the ABCDE-ultrasound approach, a systematic ultrasound evaluation of the heart, lungs and respiratory muscle pump, in patients with weaning failure.

Utility of ultrasound assessment of diaphragmatic function before and after pulmonary rehabilitation in COPD patients

Background

Pulmonary rehabilitation (PR) may improve respiratory symptoms and skeletal muscle strength in patients with COPD. We aimed to evaluate changes in ultrasound (US) measurements of diaphragmatic mobility and thickness after PR in COPD patients and to test its correlation with PR outcomes.

Methods

Twenty-five COPD patients were enrolled and underwent a diaphragm US assessment before and after a 12-week PR program.

Results

We found a correlation between the intraindividual percentage of change in the diaphragmatic length of zone of apposition at functional residual capacity (ΔLzapp%) and the change in 6-minute walking distance (6MWD) after PR (rho=0.49, P=0.02). ΔLzapp% was significantly higher in patients with improved 6MWD and COPD Assessment Test (CAT) score (mean rank=12.03±2.57 vs 6.88±4.37; P=0.02). A ΔLzapp% of ≥10% was able to discriminate among patients with improved 6MWD, with a sensitivity of 83% and a specificity of 74%. The area under the receiver operating characteristic curve for ΔLzapp% was 0.83. A cutoff value of ≥9% of ΔLzapp% had a positive predictive value in discriminating a reduction in ≥2 points of CAT score after PR, with a sensitivity and a specificity of 80% and 62%, respectively.

Conclusion

Diaphragm US assessment represents a useful prognostic marker of PR outcomes in COPD patients.

[Exploring the diaphragm: Ultrasound is essential]

The diaphragm is the muscle most implicated in breathing. Its morphological exploration usually depends on pulmonary radiography, fluoroscopy, CT-scanning and MRI. Its function is evaluated by the classical respiratory functional tests, the measurement of maximum inspiratory and expiratory pressures, the transdiaphragmatic pressure and even an electromyogram. Ultrasound is a technique still insufficiently used in respiratory medicine. It offers, however, many advantages: it is easy to implement, there is no irradiation, it is usable at the bedside, particularly when the patient is immobile or in intensive care. The results of the examination are immediately available. It allows morphological and dynamic study of each hemidiaphragm as well as providing invaluable information on the thoracic and subdiaphragmatic environment. Its field of exploration is extremely wide: raised hemidiaphragm, dyspnea following a stroke or a surgical procedure (thoracic or abdominal), road accident trauma, diagnosis and follow-up of a paresis or paralysis, evaluation of diaphragmatic mobility during the course of COPD (Chronic Obstructive Pulmonary Disease) and many other pathologies. Ultrasound is insufficiently used in pleural disease and even less so in the evaluation of the morphology and function of the diaphragm.

Interpreting diaphragmatic movement with bedside imaging, review article

The diaphragm is the most important muscle of respiration. At equilibrium, the load imposed on the diaphragmatic muscles from transdiaphragmatic pressure balances the force generated by diaphragmatic muscles. However, procedural and nonprocedural thoracic and abdominal conditions may disrupt this equilibrium and impair diaphragmatic function. Diaphragmatic dysfunction is associated with respiratory insufficiency and poor outcome. Therefore, rapid diagnosis and early intervention may be useful. Ultrasound imaging provides quick and accurate bedside assessment of the diaphragm. Various imaging techniques have been suggested, using 2-dimensional and M-mode technology. Diaphragm viewing depends on the degree of robe movement, determined by the angle of incidence of the ultrasound beam and by the direction of probe movement. In this review, we will discuss the function of the diaphragm focusing on clinically important anatomical and physiological properties of the diaphragm. We will review the literature regarding various sonographic techniques for diaphragm assessment. We will also explore the evidence for the role of the tidal displacement of subdiaphragmatic organs as a surrogate for diaphragm movement.

Diaphragm ultrasound as indicator of respiratory effort in critically ill patients undergoing assisted mechanical ventilation: a pilot clinical study

Introduction

Pressure-support ventilation, is widely used in critically ill patients; however, the relative contribution of patient’s effort during assisted breathing is difficult to measure in clinical conditions. Aim of the present study was to evaluate the performance of ultrasonographic indices of diaphragm contractile activity (respiratory excursion and thickening) in comparison to traditional indices of inspiratory muscle effort during assisted mechanical ventilation.

Method

Consecutive patients admitted to the ICU after major elective surgery who met criteria for a spontaneous breathing trial with pressure support ventilation were enrolled. Patients with airflow obstruction or after thoracic/gastric/esophageal surgery were excluded. Variable levels of inspiratory muscle effort were achieved by delivery of different levels of ventilatory assistance by random application of pressure support (0, 5 and 15 cmH₂O). The right hemidiaphragm was evaluated by B- and M-mode ultrasonography to record respiratory excursion and thickening. Airway, gastric and oesophageal pressures, and airflow were recorded to calculate indices of respiratory effort (diaphragm and esophageal pressure–time product).

Results

25 patients were enrolled. With increasing levels of pressure support, parallel reductions were found between diaphragm thickening and both diaphragm and esophageal pressure–time product (respectively, R = 0.701, p < 0.001 and R = 0.801, p < 0.001) during tidal breathing. No correlation was found between either diaphragm or esophageal pressure–time product and diaphragm excursion (respectively, R = −0.081, p = 0.506 and R = 0.003, p = 0.981), nor was diaphragm excursion correlated to diaphragm thickening (R = 0.093, p = 0.450) during tidal breathing.

Conclusions

In patients undergoing in assisted mechanical ventilation, diaphragm thickening is a reliable indicator of respiratory effort, whereas diaphragm excursion should not be used to quantitatively assess diaphragm contractile activity.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-015-0894-9) contains supplementary material, which is available to authorized users.

Guiding intramuscular diaphragm injections using real-time ultrasound and electromyography

INTRODUCTION

We describe a unique method that combines ultrasound and electromyography to guide intramuscular diaphragm injections in anesthetized large animals.

METHODS

Ultrasound was used to visualize the diaphragm on each side of spontaneously breathing, anesthetized beagle dogs and cynomolgus macaques. An electromyography (EMG) needle was introduced and directed by ultrasound to confirm that the needle entered the muscular portion of the diaphragm, and methylene blue was injected. Injection accuracy was confirmed upon necropsy by tracking the spread of methylene blue.

RESULTS

All methylene blue injections were confirmed to have been placed appropriately into the diaphragm.

CONCLUSIONS

This study demonstrates the feasibility and accuracy of using ultrasound and EMG to guide injections and to reduce complications associated with conventional blind techniques. Ultrasound guidance can be used for clinical EMG of the diaphragm. Future applications may include targeted diaphragm injections with gene replacement therapy in neuromuscular diseases.