Diaphragm Dysfunction in Critical Illness

The Application of Diaphragm Ultrasound in Chronic Obstructive Pulmonary Disease: A Narrative Review

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.

Suppression of Ventilation-Induced Diaphragm Fibrosis through the Phosphoinositide 3-Kinase-γ in a Murine Bleomycin-Induced Acute Lung Injury Model

Mechanical ventilation (MV), used in patients with acute lung injury (ALI), induces diaphragmatic myofiber atrophy and contractile inactivity, termed ventilator-induced diaphragm dysfunction. Phosphoinositide 3-kinase-γ (PI3K-γ) is crucial in modulating fibrogenesis during the reparative phase of ALI; however, the mechanisms regulating the interactions among MV, myofiber fibrosis, and PI3K-γ remain unclear. We hypothesized that MV with or without bleomycin treatment would increase diaphragm muscle fibrosis through the PI3K-γ pathway. Five days after receiving a single bolus of 0.075 units of bleomycin intratracheally, C57BL/6 mice were exposed to 6 or 10 mL/kg of MV for 8 h after receiving 5 mg/kg of AS605240 intraperitoneally. In wild-type mice, bleomycin exposure followed by MV 10 mL/kg prompted significant increases in disruptions of diaphragmatic myofibrillar organization, transforming growth factor-β1, oxidative loads, Masson's trichrome staining, extracellular collagen levels, positive staining of α-smooth muscle actin, PI3K-γ expression, and myonuclear apoptosis (p < 0.05). Decreased diaphragm contractility and peroxisome proliferator-activated receptor-γ coactivator-1α levels were also observed (p < 0.05). MV-augmented bleomycin-induced diaphragm fibrosis and myonuclear apoptosis were attenuated in PI3K-γ-deficient mice and through AS605240-induced inhibition of PI3K-γ activity (p < 0.05). MV-augmented diaphragm fibrosis after bleomycin-induced ALI is partially mediated by PI3K-γ. Therapy targeting PI3K-γ may ameliorate MV-associated diaphragm fibrosis.

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.

Protective role of pretreatment with Anisodamine against sepsis-induced diaphragm atrophy via inhibiting JAK2/STAT3 pathway

There is an increasing tendency for sepsis patients to suffer from diaphragm atrophy as well as mortality. Therefore, reducing diaphragm atrophy could benefit sepsis patients' prognoses. Studies have shown that Anisodamine (Anis) can exert antioxidant effects when blows occur. However, the role of Anisodamine in diaphragm atrophy in sepsis patients has not been reported. Therefore, this study investigated the antioxidant effect of Anisodamine in sepsis-induced diaphragm atrophy and its mechanism. We used cecal ligation aspiration (CLP) to establish a mouse septic mode and stimulated the C2C12 myotube model with lipopolysaccharide (LPS). After treatment with Anisodamine, we measured the mice's bodyweight, diaphragm weight, fiber cross-sectional area and the diameter of C2C12 myotubes. The malondialdehyde (MDA) levels in the diaphragm were detected using the oxidative stress kit. The expression of MuRF1, Atrogin1 and JAK2/STAT3 signaling pathway components in the diaphragm and C2C12 myotubes was measured by RT-qPCR and Western blot. The mean fluorescence intensity of ROS in C2C12 myotubes was measured by flow cytometry. Meanwhile, we also measured the levels of Drp1 and Cytochrome C (Cyt-C) in vivo and in vitro by Western blot. Our study revealed that Anisodamine alleviated the reduction in diaphragmatic mass and the loss of diaphragmatic fiber cross-sectional area and attenuated the atrophy of the C2C12 myotubes by inhibiting the expression of E3 ubiquitin ligases. In addition, we observed that Anisodamine inhibited the JAK2/STAT3 signaling pathway and protects mitochondrial function. In conclusion, Anisodamine alleviates sepsis-induced diaphragm atrophy, and the mechanism may be related to inhibiting the JAK2/STAT3 signaling pathway.

Chest Dynamic MRI as Early Biomarker of Respiratory Impairment in Amyotrophic Lateral Sclerosis Patients: A Pilot Study

Background: Amyotrophic lateral sclerosis (ALS) is a neuromuscular progressive disorder characterized by limb and bulbar muscle wasting and weakness. A total of 30% of patients present a bulbar onset, while 70% have a spinal outbreak. Respiratory involvement represents one of the worst prognostic factors, and its early identification is fundamental for the early starting of non-invasive ventilation and for the stratification of patients. Due to the lack of biomarkers of early respiratory impairment, we aimed to evaluate the role of chest dynamic MRI in ALS patients. Methods: We enrolled 15 ALS patients and 11 healthy controls. We assessed the revised ALS functional rating scale, spirometry, and chest dynamic MRI. Data were analyzed by using the Mann-Whitney U test and Cox regression analysis. Results: We observed a statistically significant difference in both respiratory parameters and pulmonary measurements at MRI between ALS patients and healthy controls. Moreover, we found a close relationship between pulmonary measurements at MRI and respiratory parameters, which was statistically significant after multivariate analysis. A sub-group analysis including ALS patients without respiratory symptoms and with normal spirometry values revealed the superiority of chest dynamic MRI measurements in detecting signs of early respiratory impairment. Conclusions: Our data suggest the usefulness of chest dynamic MRI, a fast and economically affordable examination, in the evaluation of early respiratory impairment in ALS patients.

Understanding the Risk Factors and Pathogenesis of Disseminated Nocardiosis in Immunocompromised Patients

Nocardia is a genus of aerobic, Gram-positive, partially acid-fast, filamentous bacilli notoriously known for causing multisystemic infections in immunocompromised individuals. Notably, this genus of bacteria commonly infects the pleural and central nervous system, leading to pneumonia and brain abscesses, respectively. Our patient is a 71-year-old female who initially presented to the emergency department complaining of shortness of breath and altered mental status. Imaging revealed multiple enhancing brain lesions, a pleural effusion, and a paraspinal abscess, which upon aspiration and culture demonstrated Nocardia farcinica/kroppenstedtii. The patient underwent antibiotic treatment, including intravenous (IV) imipenem and trimethoprim/sulfamethoxazole (TMP-SMX), before being transitioned to oral TMP-SMX and amoxicillin/clavulanate. This case demonstrates the importance of diagnosing nocardiosis acutely and treating it appropriately.

Ultrasound evaluation of diaphragm kinetics after minimally invasive surfactant administration

PURPOSE

Concerns remain on different alveolar deposition of surfactant between LISA and INSURE methods. Ultrasound evaluation of diaphragm kinetics may provide clinical evidence on this issue, as indirect representation of the respiratory system compliance.

METHODS

This was a prospective-observational pilot study. The inclusion criterion was CPAP-supported infants ≤ 32 weeks with RDS receiving surfactant via minimally invasive technique. 52 patients randomized for surfactant administration via LISA or INSURE methods were enrolled. Right diaphragm (RD) global mean peak velocity (MPV) by Pulsed-Wave Tissue Doppler Imaging (PTDI) was recorded before and two hours after surfactant administration with simultaneous measurements of oxygen saturation (SpO2)/fraction of inspired oxygen (FiO2) (SF ratio). Mechanical ventilation ≤ 72 h from birth represented treatment failure.

RESULTS

LISA infants had significantly higher gestational age (p = 0.029) and birth weight (p = 0.030) with lower CRIB-II scores (p = 0.030) than INSURE infants. LISA infants showed higher median MPV at baseline RD-PTDI US assessment (p = 0.024), but post-surfactant median MPV and other the investigated variables were similar at the adjusted analysis for gestational age and sedation. 8/52 (15%) infants who failed treatment had a significantly lower SF ratio (p = 0.002) and higher median MPV at RD-PTDI US (p = 0.004) after surfactant administration, despite the higher CPAP support level before (p = 0.007) and after (p = 0.001) surfactant administration. A full course of antenatal steroids was protective against mechanical ventilation (p = 0.038).

CONCLUSIONS

Different minimally invasive surfactant administration techniques do not appear to influence diaphragm kinetics evaluated by RD-PTDI US.

Ultrasonography to Access Diaphragm Dysfunction and Predict the Success of Mechanical Ventilation Weaning in Critical Care: A Narrative Review

INTRODUCTION

Weaning failure is common in mechanically ventilated patients, and whether ultrasound (US) can predict weaning outcome remains controversial. This review aims to evaluate the diaphragmatic function measured by US as a predictor of weaning outcome.

METHODS

PubMed was searched to identify original articles about the use of diaphragmatic US in ICU patients. A total of 61 citations were retrieved initially; available data of 26 studies were included in this review.

RESULTS

To assess diaphragmatic dysfunction in adults, six studies evaluated excursion, five evaluated thickening fraction, and both in nine. Despite heterogeneity in the diagnostic accuracy of diaphragm US among the studies, the sonographic indices showed good diagnostic performance for predicting weaning outcome.

CONCLUSIONS

Diaphragmatic US can be a useful and accurate tool to detect diaphragmatic dysfunction in critically ill patients and predict weaning outcome.

The molecular mechanism of sepsis-induced diaphragm dysfunction

Background

No effective drugs for the treatment of sepsis-induced diaphragm dysfunction are currently available. Therefore, it is particularly important to clarify the molecular regulatory mechanism of this condition and subsequently implement effective treatment and prevention of sepsis-induced diaphragm dysfunction.

Methods

A mouse model of diaphragm dysfunction was established via injection of lipopolysaccharide (LPS). An RNA-sequencing (RNA-seq) technique was used to detect the differentially expressed genes (DEGs) in the diaphragms of mice. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed for functional analysis of DEGs. The protein-protein interaction network obtained from the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) website was imported into Cytoscape, the key molecular regulatory network was constructed with CytoNCA, the ClueGo plugin was further used to analyze the core regulatory pathways of key molecular, and finally, the iRegulon plugin was used to the identify key transcription factors.

Results

The genes upregulated after LPS treatment were involved in biological processes and pathways related to immune response; the genes downregulated after LPS treatment were mainly correlated with the muscle contraction. The expressions of several inflammation-related genes were upregulated after LPS treatment, of which tumor necrosis factor (Tnf), interleukin (Il)-1β, and Il-6 assumed a core regulatory role in the network; meanwhile, the downregulated key genes included Col1a1, Uqcrfs1, Sdhb, and ATP5a1, among others. These key regulatory factors participated in the activation of Toll-like receptor (TLR) signaling pathway, nuclear factor (NF)-κB signaling pathway, and TNF signaling pathway as well as the inhibition of oxidative phosphorylation pathway, cardiac muscle contraction pathway, and citrate cycle pathway. Finally, RelA, IRF1, and STAT3, were identified as the key regulators in the early stage of diaphragmatic inflammatory response.

Conclusions

Sepsis-induced diaphragm dysfunction in mice is closely correlated with the activation of TLR signaling pathway, NF-κB signaling pathway, and TNF signaling pathway and the inhibition of oxidative phosphorylation pathway, cardiac muscle contraction pathway, and citrate cycle pathway. Our findings provide insight into the molecular mechanism of sepsis-induced diaphragm dysfunction in mice and provide a promising new strategy for targeted treatment of diaphragm dysfunction.

Electrical stimulation mitigates muscle degradation shift in gene expressions during 12-h mechanical ventilation

Ventilator-induced diaphragm dysfunction (VIDD), a dysfunction of the diaphragm muscle caused by prolonged mechanical ventilation (MV), is an important factor that hinders successful weaning from ventilation. We evaluated the effects of electrical stimulation of the diaphragm muscle (pulsed current with off-time intervals) on genetic changes during 12 h of MV (E-V12). Rats were divided into four groups: control, 12-h MV, sham operation, and E-V12 groups. Transcriptome analysis using an RNA microarray revealed that 12-h MV caused upregulation of genes promoting muscle atrophy and downregulation of genes facilitating muscle synthesis, suggesting that 12-h MV is a reasonable method for establishing a VIDD rat model. Of the genes upregulated by 12-h MV, 18 genes were not affected by the sham operation but were downregulated by E-V12. These included genes related to catabolic processes, inflammatory cytokines, and skeletal muscle homeostasis. Of the genes downregulated by 12-h MV, 6 genes were not affected by the sham operation but were upregulated by E-V12. These included genes related to oxygen transport and mitochondrial respiration. These results suggested that 12-h MV shifted gene expression in the diaphragm muscle toward muscle degradation and that electrical stimulation counteracted this shift by suppressing catabolic processes and increasing mitochondrial respiration.

Fu's subcutaneous needling as an adjunctive therapy for diaphragmatic dysfunction in a critically ill patient with severe neurologic disability: A case report

RATIONALE

Diaphragmatic dysfunction is prevalent among intensive care unit patients. The use of Fu's subcutaneous needling (FSN) for respiratory problems is a new issue and few study has been conducted so far.

PATIENT CONCERNS

Despite conventional treatments, the patient continued using noninvasive ventilation after discharge from the intensive care unit due to diaphragmatic dysfunction.

DIAGNOSIS

Diaphragmatic dysfunction.

INTERVENTIONS

After the myofascial trigger points were confirmed in the neck, chest, and abdomen area, FSN therapy was performed using disposable FSN needles. FSN needles were penetrated into the subcutaneous layer.

OUTCOMES

The patient dyspnea and tachypnea improved, and noninvasive ventilation time dropped significantly. The patient was successfully weaned from the ventilator after 3 sessions of FSN therapy, and there was an increase in diaphragmatic excursion and tidal fraction of the diaphragm via the ultrasound imaging. We found no evidence of relapse 12 months after treatment.

LESSONS

FSN therapy has potential as an alternative strategy for patients with diaphragmatic dysfunction and severe neurologic disabilities who do not respond well to conventional therapies, but further research is still required to establish the effects of FSN on diaphragmatic function.

Imaging of the Diaphragm Following Cardiac Surgery: Focus on Ultrasonographic Assessment

Diaphragm dysfunction is a common complication following cardiac surgery. Its clinical impact is variable, ranging from the absence of symptoms to the acute respiratory failure. Post-operative diaphragm dysfunction may negatively affect patients' prognosis delaying the weaning from the mechanical ventilation (MV), extending the time of hospitalization and increasing mortality. Ultrasonography is a valid tool to evaluate diaphragmatic impairment in different settings, like the Intensive Care Unit, to predict successful weaning from the MV, and the Cardiovascular Rehabilitation Unit, to stratify patients in terms of risk of functional recovery failure. The aim of this review is to describe the pathophysiology of post-cardiac surgery diaphragm dysfunction, the techniques used for its diagnosis and the potential applications of diaphragm ultrasound.

Research progress on the pathogenesis and treatment of ventilator-induced diaphragm dysfunction

Prolonged controlled mechanical ventilation (CMV) can cause diaphragm fiber atrophy and inspiratory muscle weakness, resulting in diaphragmatic contractile dysfunction, called ventilator-induced diaphragm dysfunction (VIDD). VIDD is associated with higher rates of in-hospital deaths, nosocomial pneumonia, difficulty weaning from ventilators, and increased costs. Currently, appropriate clinical strategies to prevent and treat VIDD are unavailable, necessitating the importance of exploring the mechanisms of VIDD and suitable treatment options to reduce the healthcare burden. Numerous animal studies have demonstrated that ventilator-induced diaphragm dysfunction is associated with oxidative stress, increased protein hydrolysis, disuse atrophy, and calcium ion disorders. Therefore, this article summarizes the molecular pathogenesis and treatment of ventilator-induced diaphragm dysfunction in recent years so that it can be better served clinically and is essential to reduce the duration of mechanical ventilation use, intensive care unit (ICU) length of stay, and the medical burden.

Pleuropulmonary and diaphragmatic ultrasound in intensive care medicine

The usefulness of ultrasound for chest exploration was described in 1968. It was not until the 1990s, when its use became widespread in Intensive Care Units as a diagnostic, monitoring and procedural guide tool. The fact that it is a non-invasive tool, accessible at the bedside, with a sensitivity and specificity close to computerized tomography (CT) and with a short learning curve, have made it a mandatory technique in the management of critically ill patients. It is essential to know that there are different air/fluid ratio generated by different pathologies that gives rise to one echographic pattern or another. The identification of these patterns together with the clinical information will allow to make an accurate diagnosis in most settings of respiratory failure. Likewise, we must not forget the importance of evaluating diaphragmatic function by ultrasound during weaning from mechanical ventilation.

Acute muscle loss and early effects of COVID-19 on skeletal muscle in adult patients: A retrospective cohort study

OBJECTIVES

It is known that COVID-19 has multisystemic effects. However, its early effects on muscle tissue have not been clearly elucidated. The aim of this study is to investigate early changes in the pectoral muscle in patients with COVID-19 infection.

MATERIALS AND METHODS

The pectoral muscle areas (PMA) and pectoral muscle index (PMI) of 139 patients diagnosed with COVID-19 were measured from chest CTs taken at the time of the first diagnosis and within 6 months after the diagnosis. The effect of the infection on the muscle area was investigated by evaluating whether there was a change between the two measurements. Lung involvement of the infection in the first CT was scored with the CT severity score (CT-SS). In addition, the effects of patients' clinics, CT-SS, length of hospital stay, and intubation history on changes in the muscle area were investigated.

RESULTS

When the PMA and PMI values were compared, there was a statistically significant decrease in the values in the control CT group compared to the first diagnosis CT group. The difference was found higher in intubated patients. CT-SS was associated with a decrease in PMI.

CONCLUSION

COVID-19 is one of the causes of acute sarcopenia. Pectoralis muscle is part of the skeletal muscle, and there may be a decrease in the muscle area in the early period of the disease.

Ultrasonographic evaluation of the diaphragm in critically ill patients to predict invasive mechanical ventilation

BACKGROUND

Diaphragm dysfunction is common in critically ill patients and associated with poorer outcomes. The function of the diaphragm can be evaluated at the bedside by measuring diaphragmatic excursion using ultrasonography. In this study, we investigated the ability of right-sided diaphragmatic excursion (RDE) to predict the need for invasive mechanical ventilation (IMV).

METHODS

Critically ill patients aged 18 years and older who presented to our emergency department between May 20, 2021 and May 19, 2022 and underwent measurement of RDE within 10 min of arrival were enrolled in this prospective study. The ability of RDE to predict the need for IMV was assessed by multivariable logistic regression and analysis of the area under the receiver-operating characteristic curve (AUROC).

RESULTS

A total of 314 patients were enrolled in the study; 113 (35.9%) of these patients required IMV. An increase of RDE value per each 0.1 cm was identified to be an independent predictor of IMV (adjusted odds ratio 0.08, 95% confidence interval [CI] 0.04-0.17, p < 0.001; AUROC 0.850, 95% CI 0.807-0.894). The RDE cutoff value was 1.2 cm (sensitivity 82.3%, 95% CI 74.0-88.8; specificity 78.1%, 95% CI 71.7-83.6). Time on a ventilator was significantly longer when the RDE was ≤ 1.2 cm (13 days [interquartile range 5, 27] versus 5 days [interquartile range 3, 8], p = 0.006).

CONCLUSIONS

In this study, RDE had a good ability to predict the need for IMV in critically ill patients. The optimal RDE cutoff value was 1.2 cm. Its benefit in patient management requires further investigation.

Prognostic Value of Diaphragm Diameter, Muscle Volume, and Bone Mineral Density in Critically Ill COVID-19 Patients

Objective: We aimed to analyze the prognostic value of muscle volume (MV), bone mineral density (BMD), and diaphragm diameter (DD) in COVID-19. Method: The study included 498 patients admitted to the intensive care unit (ICU) with a positive polymerase chain reaction test for COVID-19 from March 11, 2020, through August 31, 2022. The patients' laboratory and demographic data of the patients at the time of ICU admission were recorded. MV, DD, and BMD measurements were performed using computed tomography examinations. Muscle index (MI) was calculated as MV/height2. Quartiles were determined for all 4 measurements. Patients in the lowest quartile were recorded as having low MV, MI, DD, and BMD values. The parameters were evaluated for the whole group and compared according to gender and mortality. The multiple regression analysis was performed for the prediction of mortality. Results: In the mortality group, the male and female patients had significantly statistically lower values in MV (P < .001 and P = .002, respectively), MI (P < .001 and P = .005, respectively), DD (P < .001 and P < .001, respectively), and BMD (P = .002 and P < .001, respectively). In the multiple regression analysis, low MI (OR: 2.03, 95% CI: 1.14-3.61, P = .016) and DD (OR: 10.47, 95% CI: 5.59-19.59, P < .001) values remained significant for the prediction of mortality. Conclusion: BMD is a risk factor for mortality in patients with severe COVID-19, but cannot be used as an independent predictor. However, MI and DD can be used as independent predictors of mortality even in severe cases.

Transcutaneous electrical diaphragmatic stimulation in mechanically ventilated patients: a randomised study

BACKGROUND

Few specific methods are available to reduce the risk of diaphragmatic dysfunction for patients under mechanical ventilation. The number of studies involving transcutaneous electrical stimulation of the diaphragm (TEDS) is increasing but none report results for diaphragmatic measurements, and they lack power. We hypothesised that the use of TEDS would decrease diaphragmatic dysfunction and improve respiratory muscle strength in patients in ICU.

METHODS

We conducted a controlled trial to assess the impact of daily active electrical stimulation versus sham stimulation on the prevention of diaphragm dysfunction during the weaning process from mechanical ventilation. The evaluation was based on ultrasound measurements of diaphragm thickening fraction during spontaneous breathing trials. We also measured maximal inspiratory muscle pressure (MIP), peak cough flow (PEF) and extubation failure.

RESULTS

Sixty-six patients were included and randomised using a 1:1 ratio. The mean number of days of mechanical ventilation was 10 ± 6.8. Diaphragm thickening fraction was > 30% at the SBT for 67% of participants in the TEDS group and 54% of the Sham group (OR1.55, 95% CI 0.47-5.1; p = 0.47). MIP and PEF were similar in the TEDS and Sham groups (respectively 35.5 ± 11.9 vs 29.7 ± 11.7 cmH20; p = 0.469 and 83.2 ± 39.5 vs. 75.3 ± 34.08 L/min; p = 0.83). Rate of extubation failure was not different between groups.

CONCLUSION

TEDS did not prevent diaphragm dysfunction or improve inspiratory muscle strength in mechanically ventilated patients.

TRIAL REGISTRATION

Prospectively registered on the 20th November 2019 on ClinicalTrials.gov Identifier NCT04171024.

[Intensive care unit-acquired weakness-Diagnostic value of neuromuscular ultrasound]

Intensive care unit-acquired weakness (ICUAW) is one of the most common neuromuscular complications in intensive care medicine. The clinical diagnosis and assessment of the severity using established diagnostic methods (e.g., clinical examination using the Medical Research Council Sum Score or electrophysiological examination) can be difficult or even impossible, especially in sedated, ventilated and delirious patients. Neuromuscular ultrasound (NMUS) has increasingly been investigated in ICUAW as an easy to use noninvasive and mostly patient compliance-independent diagnostic alternative. It has been shown that NMUS appears to be a promising tool to detect ICUAW, to assess the severity of muscular weakness and to monitor the clinical progression. Further studies are needed to standardize the methodology, to evaluate the training effort and to optimize outcome predication. The formulation of an interdisciplinary neurological and anesthesiological training curriculum is warranted to establish NMUS as a complementary diagnostic method of ICUAW in daily clinical practice.

Clinical utility of diaphragmatic ultrasonography for mechanical ventilator weaning in adults: A study protocol for systematic review and meta-analysis

Background and Aims

Mechanical ventilation is associated with several risks, including barotrauma, ventilator-associated pneumonia, and ventilator-induced diaphragmatic dysfunction. A delay in weaning from mechanical ventilation increases these risks, and prolonged weaning has been shown to increase hospital mortality. Various tools have been used in clinical practice to predict successful weaning from mechanical ventilation; however, they have a low prognostic accuracy. The use of ultrasonography in intensive care units is an area of growing interest since it is a noninvasive, convenient, and safe modality. Since ultrasonography can provide real-time assessment of diaphragmatic morphology and function, it may have clinical utility in predicting successful mechanical ventilator weaning. This study aimed to describe a protocol to assess the effectiveness of diaphragmatic ultrasonography in the decision-making process for ventilator weaning in terms of its impact on clinical outcomes.

Methods

This systematic review of published analytical research will use an aggregative thematic approach according to the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols guidelines. We will perform a comprehensive search for studies on the MEDLINE, Embase, and Cochrane Central Register of Controlled Trials databases. Two authors will independently perform abstract and full-text screening and data extraction. Additionally, a meta-analysis and the risk of bias evaluation will be conducted, as appropriate.

Conclusion

Systematic reviews on the effectiveness of diaphragmatic ultrasonography in the decision-making process for ventilator weaning in terms of its impact on clinical outcomes are lacking. The results of this systematic review may serve as a basis for future clinical trials. Systematic review registration: This protocol was registered with the Open Science Framework: https://osf.io/cn8xf.

The Incidence of Diaphragmatic Dysfunction in Patients Presenting With Dyspnea in the Emergency Department

OBJECTIVES

Diaphragmatic dysfunction has been reported as a cause of dyspnea, and its diagnosis can be made using ultrasound. Diaphragmatic ultrasound is mainly used to predict respiratory failure in chronic conditions. The use of diaphragmatic ultrasound has also risen in acute settings, such as emergency departments (EDs). However, the number of studies on its use still needs to be increased. The present study aimed to find the incidence of diaphragmatic dysfunction in the ED.

METHODS

This prospective cohort study was conducted in an ED. We enrolled patients aged greater than 18 years who presented with dyspnea. Diaphragmatic excursion and diaphragmatic thickness techniques were performed. The primary outcome was the incidence of diaphragmatic dysfunction. The secondary outcomes were the associations between diaphragmatic dysfunction and the composition of respiratory therapies within 24 hours, intubation within 24 hours, and 7-day mortality.

RESULTS

A total of 237 patients were analyzed. The incidences of diaphragmatic dysfunction assessed by diaphragmatic excursion and diaphragm thickness were 22.4 and 32.1%, respectively. Patients with sepsis and cancer had the highest incidences. Diaphragmatic dysfunction assessed by both techniques was not associated with the composition of respiratory support therapies within 24 hours, intubation within 24 hours, or 7-day mortality.

CONCLUSIONS

The incidence of diaphragmatic dysfunction in dyspneic patients in the ED ranged from 22.4 to 32.1%, depending on the ultrasound technique. Diaphragmatic dysfunction was not associated with the composition of respiratory support therapies, intubation, or mortality.

Evaluation of IntelliVent-ASV® and PS-SIMV Mode Using Ultrasound (US) Measurements in Terms of Diaphragm Atrophy

BACKGROUND

 Mechanical ventilation is a life-saving intervention for critically ill patients, but it can also lead to diaphragm atrophy, which may prolong the duration of mechanical ventilation and the length of stay in the intensive care unit. IntelliVent-ASV® (Hamilton Medical, Rhäzüns, Switzerland) is a new mode of ventilation that has been developed to reduce diaphragm atrophy by promoting spontaneous breathing efforts. In this study, we aimed to evaluate the effectiveness of IntelliVent-ASV® and pressure support-synchronized intermittent mandatory ventilation (PS-SIMV) mode in reducing diaphragm atrophy by measuring diaphragm thickness using ultrasound (US) imaging.

METHODS

 We enrolled 60 patients who required mechanical ventilation due to respiratory failure and were randomized into two groups: IntelliVent-ASV^® and PS-SIMV. We measured the diaphragm thickness using US imaging at admission and on the seventh day of mechanical ventilation.

RESULTS

Our results showed that diaphragm thickness decreased significantly in the PS-SIMV group but remained unchanged in the IntelliVent-ASV^® group. The difference in diaphragm thickness between the two groups was statistically significant on the seventh day of mechanical ventilation.

CONCLUSIONS

IntelliVent-ASV^® may reduce diaphragm atrophy by promoting spontaneous breathing efforts. Our study suggests that this new mode of ventilation may be a promising approach to preventing diaphragm atrophy in mechanically ventilated patients. Further studies using invasive measures of diaphragm function are warranted to confirm these findings.

Temporal evolution of diaphragm thickness and diaphragm excursion among subjects hospitalized with COVID-19: A prospective observational study

BACKGROUND

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has an affinity for the angiotensin-converting enzyme 2 (ACE2) receptors, which are present abundantly on the diaphragm. This study aims to describe temporal changes in diaphragmatic thickness and excursion using ultrasonography in subjects with acute COVID-19.

METHODS

This prospective observational study included adults hospitalized with COVID-19 in the past 48 hours. The diaphragm thickness at end-expiration (DTE), diaphragm thickening fraction (DTF), and diaphragm excursion during tidal breathing (DE) and maximal inspiration (DEmax) were measured using ultrasonography daily for 5 days. The changes in DTE, DTF, DE, and Demax from day 1 to day 5 were assessed.

RESULTS

This study included 64 adults (62.5% male) with a mean (SD) age of 50.2 (17.5) years. A majority (91%) of the participants had mild or moderate illness. The median (IQR) DTE, DTF (%), DE and Demax on day 1 were 2.2 (1.9, 3.0) mm, 21.5% (14.2, 31.0), 19.2 (16.5, 24.0) mm, and 26.7 (22.0, 30.2) mm, respectively. On day 5, there was a significant reduction in the DTE (p=0.002) with a median (IQR) percentage change of -15.7% (-21.0, 0.0). The DTF significantly increased on day 5 with a median (IQR) percentage change of 25.0% (-19.2, 98.4), p=0.03. There was no significant change in DE and Demax from day 1 to day 5, with a median (IQR) percentage change of 3.6% (-5.2, 15) and 0% (-6.7, 5.9), respectively.

CONCLUSIONS

Non-intubated patients with COVID-19 exhibited a temporal decline in diaphragm thickness with increase in thickening fraction over 5 days of hospital admission. Further research is warranted to assess the impact of COVID-19 pneumonia on diaphragmatic function.

A Trend towards Diaphragmatic Muscle Waste after Invasive Mechanical Ventilation in Multiple Trauma Patients-What to Expect?

Considering the prioritization of life-threatening injuries in trauma care, secondary dysfunctions such as ventilator-induced diaphragmatic dysfunction (VIDD) are often overlooked. VIDD is an entity induced by muscle inactivity during invasive mechanical ventilation, associated with a profound loss of diaphragm muscle mass. In order to assess the incidence of VIDD in polytrauma patients, we performed an observational, retrospective, longitudinal study that included 24 polytraumatized patients. All included patients were mechanically ventilated for at least 48 h and underwent two chest CT scans during their ICU stay. Diaphragmatic thickness was measured by two independent radiologists on coronal and axial images at the level of celiac plexus. The thickness of the diaphragm was significantly decreased on both the left and right sides (left side: -0.82 mm axial p = 0.034; -0.79 mm coronal p = 0.05; right side: -0.94 mm axial p = 0.016; -0.91 coronal p = 0.013). In addition, we obtained a positive correlation between the number of days of mechanical ventilation and the difference between the two measurements of the diaphragm thickness on both sides (r =0.5; p = 0.02). There was no statistically significant correlation between the body mass indexes on admission, the use of vitamin C or N-acetyl cysteine, and the differences in diaphragmatic thickness.

Neuromuscular Ultrasound in Intensive Care Unit-Acquired Weakness: Current State and Future Directions

Intensive care unit-acquired weakness (ICUAW) is one of the most common causes of muscle atrophy and functional disability in critically ill intensive care patients. Clinical examination, manual muscle strength testing and monitoring are frequently hampered by sedation, delirium and cognitive impairment. Many different attempts have been made to evaluate alternative compliance-independent methods, such as muscle biopsies, nerve conduction studies, electromyography and serum biomarkers. However, they are invasive, time-consuming and often require special expertise to perform, making them vastly impractical for daily intensive care medicine. Ultrasound is a broadly accepted, non-invasive, bedside-accessible diagnostic tool and well established in various clinical applications. Hereby, neuromuscular ultrasound (NMUS), in particular, has been proven to be of significant diagnostic value in many different neuromuscular diseases. In ICUAW, NMUS has been shown to detect and monitor alterations of muscles and nerves, and might help to predict patient outcome. This narrative review is focused on the recent scientific literature investigating NMUS in ICUAW and highlights the current state and future opportunities of this promising diagnostic tool.

Respiratory muscle ultrasonography evaluation and its clinical application in stroke patients: A review

Background

Respiratory muscle ultrasound is a widely available, highly feasible technique that can be used to study the contribution of the individual respiratory muscles related to respiratory dysfunction. Stroke disrupts multiple functions, and the respiratory function is often significantly decreased in stroke patients.

Method

A search of the MEDLINE, Web of Science, and PubMed databases was conducted. We identified studies measuring respiratory muscles in healthy and patients by ultrasonography. Two reviewers independently extracted and documented data regarding to the criteria. Data were extracted including participant demographics, ultrasonography evaluation protocol, subject population, reference values, etc.

Result

A total of 1954 participants from 39 studies were included. Among them, there were 1,135 participants from 19 studies on diaphragm, 259 participants from 6 studies on extra-diaphragmatic inspiratory muscles, and 560 participants from 14 studies on abdominal expiratory muscles. The ultrasonic evaluation of diaphragm and abdominal expiratory muscle thickness had a relatively typically approach, while, extra-diaphragmatic inspiratory muscles were mainly used in ICU that lack of a consistent paradigm.

Conclusion

Diaphragm and expiratory muscle ultrasound has been widely used in the assessment of respiratory muscle function. On the contrary, there is not enough evidence to assess extra-diaphragmatic inspiratory muscles by ultrasound. In addition, the thickness of the diaphragm on the hemiplegic side was lower than that on the non-hemiplegic side in stroke patients. For internal oblique muscle (IO), rectus abdominis muscle (RA), transversus abdominis muscle (TrA), and external oblique muscle (EO), most studies showed that the thickness on the hemiplegic side was lower than that on the non-hemiplegic side.Clinical Trial Registration: The protocol of this review was registered in the PROSPERO database (CRD42022352901).

Temporary phrenic nerve stimulated patients: What is the role of ultrasound examination?

BACKGROUND

Prolonged mechanical ventilation caused by ventilator-induced diaphragm dysfunction (VIDD) is a serious problem in critically ill patients. Identification of patients who will have difficulty weaning from ventilation along with attempts to reduce total time on mechanical ventilation is some of the aims of intensive care medicine.

OBSERVATIONS

This article briefly summarizes current options for temporary phrenic nerve stimulation therapy in an effort to keep the diaphragm active as direct prevention and treatment of ventilator-associated diaphragmatic dysfunction in patients on mechanical ventilation. The results of feasibility studies using different approaches are promising but so far, the clinical relevance is low. One important question is which tool would reliably identify early signs of diaphragmatic dysfunction and also be useful in guiding therapy. The authors present a brief overview of the current options considering the advantages and disadvantages of the available examination modalities. Despite the fact that current data point out some limitations of ultrasound examination, we believe that it still has a unique position in the bedside examination of critically ill patients on mechanical ventilation.

CONCLUSION

Temporary phrenic nerve stimulation, regardless of the specific approach used, has the potential to directly treat or reverse VIDD, and ultrasound examination plays an important role in the comprehensive care of critically ill patients.

The Role of Thoracic Ultrasound for Diagnosis of Diseases of the Chest Wall, the Mediastinum, and the Diaphragm-Narrative Review and Pictorial Essay

The diagnostic capabilities of ultrasound extend far beyond the evaluation of the pleural space and lungs. Sonographic evaluation of the chest wall is a classic extension of the clinical examination of visible, palpable, or dolent findings. Unclear mass lesions of the chest wall can be differentiated accurately and with low risk by additional techniques such as color Doppler imaging, contrast-enhanced ultrasound, and, in particular, ultrasound-guided biopsy. For imaging of mediastinal pathologies, ultrasound has only a complementary function but is valuable for guidance of percutaneous biopsies of malignant masses. In emergency medicine, ultrasound can verify and support correct positioning of endotracheal tubes. Diaphragmatic ultrasound benefits from the real-time nature of sonographic imaging and is becoming increasingly important for the assessment of diaphragmatic function in long-term ventilated patients. The clinical role of thoracic ultrasound is reviewed in a combination of narrative review and pictorial essay.

Accuracy of lung and diaphragm ultrasound in predicting successful extubation in extremely preterm infants: A prospective observational study

OBJECTIVE

Chest ultrasound has emerged as a promising tool in predicting extubation readiness in adults and children, yet its utility in preterm infants is lacking. Our aim was to assess the utility of lung ultrasound severity score (LUSS) and diaphragmatic function in predicting extubation readiness in extremely preterm infants.

STUDY DESIGN

In this prospective cohort study, preterm infants < 28 weeks gestational age (GA) who received invasive mechanical ventilation for ≥12 h were enrolled. Chest ultrasound was performed before extubation. The primary outcome was lung ultrasound accuracy for predicting successful extubation at 3 days. Descriptive statistics and logistic regression were done using SPSS version 22.

RESULTS

We enrolled 45 infants, of whom 36 (80%) were successfully extubated. GA and postmenstrual age (PMA) at extubation were significantly higher in the successful group. The LUSS was significantly lower in the successful group compared to failed group (11.9 ± 3.2 vs. 19.1 ± 3.1 p < 0.001). The two groups had no statistically significant difference in diaphragmatic excursion or diaphragmatic thickness fraction. Logistic regression analysis controlling for GA and PMA at extubation showed LUSS was an independent predictor for successful extubation (odd ratio 0.46, 95% confidence interval [0.23-0.9], p = 0.02). The area under the receiver operating characteristic curve was 0.95 (p ˂ 0.001) for LUSS, and a cut-off value of ≥15 had 95% sensitivity and 85% specificity in detecting extubation failure.

CONCLUSION

In extremely preterm infants, lung ultrasound has good accuracy for predicting successful extubation. However, diaphragmatic measurements were not reliable predictors.

[Acute muscle loss and early effects of COVID-19 on skeletal muscle in adult patients: a retrospective cohort study]

OBJECTIVES

It is known that COVID-19 has multisystemic effects. However, its early effects on muscle tissue have not been clearly elucidated. The aim of this study is to investigate early changes in the pectoral muscle in patients with COVID-19 infection.

MATERIALS AND METHODS

The pectoral muscle areas (PMA) and pectoral muscle index (PMI) of 139 patients diagnosed with COVID-19 were measured from chest CTs taken at the time of the first diagnosis and within 6 months after the diagnosis. The effect of the infection on the muscle area was investigated by evaluating whether there was a change between the two measurements. Lung involvement of the infection in the first CT was scored with the CT severity score (CT-SS). In addition, the effects of patients' clinics, CT-SS, length of hospital stay, and intubation history on changes in the muscle area were investigated.

RESULTS

When the PMA and PMI values were compared, there was a statistically significant decrease in the values in the control CT group compared to the first diagnosis CT group. The difference was found higher in intubated patients. CT-SS was associated with a decrease in PMI.COVID-19 is one of the causes of acute sarcopenia. Pectoralis muscle is part of the skeletal muscle, and there may be a decrease in the muscle area in the early period of the disease.

Diaphragmatic Thickness and Excursion in Preterm Infants With Bronchopulmonary Dysplasia Compared With Term or Near Term Infants: A Prospective Observational Study

BACKGROUND

Diaphragmatic atrophy associated with mechanical ventilation is reported in pediatric and adult patients, but a similar association has not been described in preterm infants with bronchopulmonary dysplasia (BPD).

RESEARCH QUESTION

Does BPD impact the diaphragm thickness (DT) and diaphragm excursion (DE) in infants born before 32 weeks' gestation compared with healthy late preterm or term infants?

STUDY DESIGN AND METHODS

In this prospective observational case-control study, DT at end of expiration (DT_exp), DT at end of inspiration (DT_ins), DT fraction (DTF), and DE (DE) were assessed using bedside ultrasound. Two groups were compared: infants with BPD (patients) and healthy, postmenstrual age-matched infants (control participants). To account for variations in body size between groups, diaphragmatic measurements were expressed as a ratio of body surface area (BSA). Statistical analyses were conducted using SAS software version 9.4 (SAS Institute, Inc.).

RESULTS

We enrolled 111 infants, including 56 preterm infants with BPD (mean ± SD study age, 37.7 ± 1.7 weeks) and 55 healthy control participants (mean ± SD study age, 38.1 ± 1.5 weeks). DT_exp and DT_exp to BSA ratio were significantly lower in the BPD group compared with the healthy control group (mean ± SD, 1.3 ± 0.4 mm vs 1.5 ± 0.4 mm [P = .01] and 7.1 ± 1.4 mm/m² vs 7.8 ± 1.8 mm/m² [P = .03]). DTF and DE were significantly higher in the BPD group vs the healthy control group (mean ± SD, 61.8 ± 26.0 vs 43.3 ± 19.7 [P < .01] and 6.0 ± 1.7 mm vs 4.4 ± 1.6 mm [P < .01], respectively).

INTERPRETATION

In infants with BPD, DT_exp was significantly lower, whereas DTF and DE were significantly higher, compared with healthy, age-matched control participants. Future studies are required and should focus on describing the evolution of diaphragmatic dimensions in preterm infants with and without BPD.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT04941963; URL: www.

CLINICALTRIALS

gov.

Closed-loop ventilation

PURPOSE OF REVIEW

The last 25 years have seen considerable development in modes of closed-loop ventilation and there are now several of them commercially available. They not only offer potential benefits for the individual patient, but may also improve the organization within the intensive care unit (ICU). Clinicians are showing both greater interest and willingness to address the issues of a caregiver shortage and overload of bedside work in the ICU. This article reviews the clinical benefits of using closed-loop ventilation modes, with a focus on control of oxygenation, lung protection, and weaning.

RECENT FINDINGS

Closed-loop ventilation modes are able to maintain important physiological variables, such as oxygen saturation measured by pulse oximetry, tidal volume (VT), driving pressure (ΔP), and mechanical power (MP), within target ranges aimed at ensuring continuous lung protection. In addition, these modes adapt the ventilator support to the patient's needs, promoting diaphragm activity and preventing over-assistance. Some studies have shown the potential of these modes to reduce the duration of both weaning and mechanical ventilation.

SUMMARY

Recent studies have primarily demonstrated the safety, efficacy, and feasibility of using closed-loop ventilation modes in the ICU and postsurgery patients. Large, multicenter randomized controlled trials are needed to assess their impact on important short- and long-term clinical outcomes, the organization of the ICU, and cost-effectiveness.

Early passive orthostatic training prevents diaphragm atrophy and dysfunction in intensive care unit patients on mechanical ventilation: A retrospective case‒control study

BACKGROUND

Intensive care unit (ICU) patients on mechanical ventilation (MV), who are always bedridden, easily develop diaphragm atrophy and dysfunction. However, few studies have assessed diaphragmatic thickness and functional changes after early passive orthostatic training.

OBJECTIVES

This is the first study to investigate the efficacy of early passive orthostatic training in preventing diaphragm atrophy and dysfunction in ICU patients on MV.

METHODS

In this randomized retrospective case‒control study, 81 ICU patients on MV for 8 days or longer were enrolled. Forty-four patients received early passive orthostatic training initiated within 72 h of MV initiation (training group), and 37 patients did not receive training (no-training group). The protocol was performed for seven days, once a day for 30 min. The primary outcomes were diaphragmatic thickness and diaphragm contractile fraction (TFdi). The ventilatory parameters were secondary outcomes.

RESULTS

This study included 81 (45 male) ICU patients on MV [(mean ± SD) age = (60.63 ± 7.88) years]. The training group had a larger diaphragmatic thickness at end-expiration (Tdi_,ee) and a smaller magnitude of decrease in Tdi_,ee and TFdi (p = 0.001, 0.029, and <0.001, respectively) than the no-training group after 7 days of training. The mean arterial pressure, fraction of inspired oxygen, and white blood cell levels were decreased in the training group compared with the no-training group (p = 0.003, 0.001, and 0.026, respectively), but lactic acid levels decreased slightly in the training group with no significant difference (p = 0.708).

CONCLUSIONS

Early passive orthostatic training is suitable to ameliorate diaphragm atrophy and dysfunction in ICU patients on MV.

Inspiratory muscle strength and function in mechanically ventilated COVID-19 survivors 3 and 6 months after intensive care unit discharge

Background

Knowledge regarding the long-term impact of invasive mechanical ventilation on the inspiratory muscles and functional outcomes in COVID-19 survivors is limited.

Methods

In this single-centre prospective cohort study, we evaluated invasively ventilated patients with COVID-19 pneumonia 3 and 6 months post-intensive care unit (ICU) discharge. Outcomes included: maximal inspiratory pressure (MIP), ultrasound parameters for diaphragm function, 6-min walk distance (6MWD), dyspnoea and quality of life. We evaluated associations between MIP and duration of mechanical ventilation with follow-up outcomes.

Results

50 COVID-19 survivors discharged from ICU between 15 October 2020 and 1 April 2021 were enrolled. Overall, survivors showed a recovery trajectory over time. However, impaired MIP remained in 24 (48%) and 12 (24%) at 3 and 6 months, respectively. Diaphragm dysfunction was not observed. At 3 months, 23 (46%) had impaired functional capacity versus 10 (20%) at 6 months. Dyspnoea persisted in 44 (88%) patients at 3 months and 38 (76%) at 6 months. Quality of life was slightly decreased at 3 months with further improvements at 6 months. MIP was correlated to 6MWD, 6MWD % predicted, dyspnoea across follow-up, and quality of life at 3 months. The duration of invasive ventilation was correlated with 6MWD and 6MWD % predicted.

Conclusion

In invasively ventilated COVID-19 survivors, inspiratory muscle strength impairments persisted 6 months after ICU discharge, while maintaining normal diaphragm function. Decreased functional capacity, dyspnoea and slightly reduced health status were observed. Early screening of survivors is of utmost importance to identify those with impairments and at risk of delayed or incomplete recovery.

The influence of mouth opening on pharyngeal pressure loss and its underlying mechanism: A computational fluid dynamic analysis

Objective: During inspiration, mechanical energy generated from respiratory muscle produces a negative pressure gradient to fulfill enough pulmonary ventilation. The pressure loss, a surrogate for energy loss, is considered as the portion of negative pressure without converting into the kinetic energy of airflow. Mouth opening (MO) during sleep is a common symptom in patients with obstructive sleep apnoea-hypopnea syndrome (OSAHS). This study aimed to evaluate the effects of mouth opening on pharyngeal pressure loss using computational fluid dynamics (CFD) simulation. Methods: A total of four subjects who were morphologically distinct in the pharyngeal characteristics based on Friedman tongue position (FTP) grades were selected. Upper airway computed tomography (CT) scan was performed under two conditions: Mouth closing (MC) and mouth opening, in order to reconstruct the upper airway models. computational fluid dynamics was used to simulate the flow on the two different occasions: Mouth closing and mouth opening. Results: The pharyngeal jet was the typical aerodynamic feature and its formation and development were different from mouth closing to mouth opening in subjects with different Friedman tongue position grades. For FTP I with mouth closing, a pharyngeal jet gradually formed with proximity to the velopharyngeal minimum area plane (plane_Amin). Downstream the plane_Amin, the jet impingement on the pharyngeal wall resulted in the frictional loss associated with wall shear stress (WSS). A rapid luminal expansion led to flow separation and large recirculation region, corresponding to the interior flow loss. They all contributed to the pharyngeal total pressure loss. While for FTP I with mouth opening, the improved velopharyngeal constriction led to smoother flow and a lower total pressure loss. For FTP IV, the narrower the plane_Amin after mouth opening, the stronger the jet formation and its impingement on the pharyngeal wall, predicting a higher frictional loss resulted from higher WSS. Besides, a longer length of the mouth opening-associated constant constrictive segment was another important morphological factor promoting frictional loss. Conclusion: For certain OSAHS patients with higher Friedman tongue position grade, mouth opening-related stronger jet formation, more jet breakdown and stronger jet flow separation might contribute to the increased pharyngeal pressure loss. It might require compensation from more inspiratory negative static pressure that would potentially increase the severity of OSAHS.

Comparison of assessment of diaphragm function using speckle tracking between patients with successful and failed weaning: a multicentre, observational, pilot study

Background

Diaphragmatic ultrasound has been increasingly used to evaluate diaphragm function. However, current diaphragmatic ultrasound parameters provide indirect estimates of diaphragmatic contractile function, and the predictive value is controversial. Two-dimensional (2D) speckle tracking is an effective technology for measuring tissue deformation and can be used to measure diaphragm longitudinal strain (DLS) to assess diaphragm function. The purpose of this study was to determine the feasibility and reproducibility of DLS quantification by 2D speckle tracking and to determine whether maximal DLS could be used to predict weaning outcomes.

Methods

This study was performed in the intensive care unit of two teaching hospitals, and was divided into two studies. Study A was a prospective study to evaluate the feasibility, reliability, and repeatability of speckle tracking in assessing DLS in healthy subjects and mechanically ventilated patients. Study B was a multicentre retrospective study to assess the use of maximal DLS measured by speckle tracking in predicting weaning outcomes.

Results

Twenty-five healthy subjects and twenty mechanically ventilated patients were enrolled in Study A. Diaphragmatic speckle tracking was easily accessible. The intra- and interoperator reliability were good to excellent under conditions of eupnoea, deep breathing, and mechanical ventilation. The intraclass correlation coefficient (ICC) ranged from 0.78 to 0.95. Ninety-six patients (fifty-nine patients were successfully weaned) were included in Study B. DLS exhibited a fair linear relationship with both the diaphragmatic thickening fraction (DTF) (R2 = 0.73, p < 0.0001) and diaphragmatic excursion (DE) (R2 = 0.61, p < 0.0001). For the prediction of successful weaning, the areas under the ROC curves of DLS, diaphragmatic thickening fraction DTF, RSBI, and DE were 0.794, 0.794, 0.723, and 0.728, respectively. The best cut-off value for predicting the weaning success of DLS was less than -21%, which had the highest sensitivity of 89.19% and specificity of 64.41%.

Conclusions

Diaphragmatic strain quantification using speckle tracking is easy to obtain in healthy subjects and mechanically ventilated patients and has a high predictive value for mechanical weaning. However, this method offers no advantage over RSBI. Future research should assess its value as a predictor of weaning.

Trial registration

This study was registered in the Chinese Clinical Trial Register (ChiCTR), ChiCTR2100049816. Registered 10 August 2021. http://www.chictr.org.cn/showproj.aspx?proj=131790

Influence of reduced muscle mass and quality on ventilator weaning and complications during intensive care unit stay in COVID-19 patients

BACKGROUND & AIMS

Sarcopenia, a loss of muscle mass, quality and function, which is particularly evident in respiratory muscles, has been associated with many clinical adverse outcomes. In this study, we aimed at evaluating the role of reduced muscle mass and quality in predicting ventilation weaning, complications, length of intensive care unit (ICU) and of hospital stay and mortality in patients admitted to ICU for SARS-CoV-2-related pneumonia.

METHODS

This was an observational study based on a review of medical records of all adult patients admitted to the ICU of a tertiary hospital in Milan and intubated for SARS-CoV-2-related pneumonia during the first wave of the COVID-19 pandemic. Muscle mass and quality measurement were retrieved from routine thoracic CT scans, when sections passing through the first, second or third lumbar vertebra were available.

RESULTS

A total of 81 patients were enrolled. Muscle mass was associated with successful extubation (OR 1.02, 95% C.I. 1.00-1.03, p = 0.017), shorter ICU stay (OR 0.97, 95% C.I. 0.95-0.99, p = 0.03) and decreased hospital mortality (HR 0.98, 95% C.I. 0.96-0.99, p = 0.02). Muscle density was associated with successful extubation (OR 1.07, 95% C.I. 1.01-1.14; p = 0.02) and had an inverse association with the number of complications in ICU (Β -0.07, 95% C.I. -0.13 - -0.002, p = 0.03), length of hospitalization (Β -1.36, 95% C.I. -2.21 - -0.51, p = 0.002) and in-hospital mortality (HR 0.88, 95% C.I. 0.78-0.99, p = 0.046).

CONCLUSIONS

Leveraging routine CT imaging to measure muscle mass and quality might constitute a simple, inexpensive and powerful tool to predict survival and disease course in patients with COVID-19. Preserving muscle mass during hospitalisation might have an adjuvant role in facilitating remission from COVID-19.

Persistent unilateral diaphragmatic paralysis in the course of Coronavirus Disease 2019 pneumonia: a case report

Coronavirus Disease 2019 infections can cause a wide range of symptoms, particularly in the respiratory system. Diaphragmatic paralysis is a rare condition that is poorly documented in the literature. We present the case of a 38-year-old Caucasian male adult who developed unilateral diaphragmatic paralysis during the course of the disease. The patient presented to the Emergency Department with fever, cough, and dyspnea, was admitted, and was immediately fitted with a high flow nasal cannula. When his condition worsened eight days later, he was admitted to the Intensive Care Unit and a tracheostomy was performed. A CT scan of the chest revealed significant left diaphragm elevation. On the 48th day, the patient gradually improved and was discharged. The paralysis of the diaphragm persisted three months later in the follow-up examination. This case illustrates a possible neuromuscular virus invasion that may have an impact on the patient's health after discharge.

The Impact of Higher Protein Intake in Patients with Prolonged Mechanical Ventilation

Prolonged mechanical ventilation (PMV) is associated with poor outcomes and a high economic cost. The association between protein intake and PMV has rarely been investigated in previous studies. This study aimed to investigate the impact of protein intake on weaning from mechanical ventilation. Patients with the PMV (mechanical ventilation ≥6 h/day for ≥21 days) at our hospital between December 2020 and April 2022 were included in this study. Demographic data, nutrition records, laboratory data, weaning conditions, and survival data were retrieved from the patient’s electronic medical records. A total of 172 patients were eligible for analysis. The patients were divided into two groups: weaning success (n = 109) and weaning failure (n = 63). Patients with daily protein intake greater than 1.2 g/kg/day had significant shorter median days of ventilator use than those with less daily protein intake (36.5 vs. 114 days, respectively, p < 0.0001). Daily protein intake ≥1.065 g/kg/day (odds ratio: 4.97, p = 0.033), daily protein intake ≥1.2 g/kg/day (odds ratio: 89.07, p = 0.001), improvement of serum albumin (odds ratio: 3.68, p = 0.027), and BMI (odds ratio: 1.235, p = 0.014) were independent predictor for successful weaning. The serum creatinine level in the 4th week remained similar in patients with daily protein intake either >1.065 g/kg/day or >1.2 g/kg/day (p = 0.5219 and p = 0.7796, respectively). Higher protein intake may have benefits in weaning in patients with PMV and had no negative impact on renal function.

High Mortality in an Older Japanese Population with Low Forced Vital Capacity and Gender-Dependent Potential Impact of Muscle Strength: Longitudinal Cohort Study

Generally, weak muscle power is associated with high mortality. We aimed to evaluate the unknown association between % predicted value forced vital capacity (FVC% predicted) and mortality in asymptomatic older people, and the impact of muscle power on this association. We analyzed the Tsurugaya cohort that enrolled Japanese people aged ≥70 for 15 years with Cox proportional hazards model. Exposure variables were FVC% predicted and leg power. The outcome was all-cause mortality. The subjects were divided into quartiles by FVC% predicted or leg power, or into two groups by 80% for FVC% predicted or by the strongest 25% for leg power. Across 985 subjects, 262 died. The males with lower FVC% predicted exhibited higher mortality risks. The hazard ratio (HR) was 2.03 (95% CI 1.30−3.18) at the lowest relative to the highest groups. The addition of leg power reduced the HR to 1.78 (95% CI 1.12−2.80). In females, FVC% predicted under 80% was a risk factor and the HR was 1.67 (95% CI 1.05−2.64) without the effect of leg power. In FVC% predicted <80% males HRs were 2.44 (95% CI 1.48−4.02) in weak and 1.38 (95% CI 0.52−3.64) in strong leg power males, relative to ≥80% and strong leg power males. Low FVC% predicted was associated with high mortality with potential unfavorable effects of weak leg power in males.

Point-of-care application of diaphragmatic ultrasonography in the emergency department for the prediction of development of respiratory failure in community-acquired pneumonia: A pilot study

Background

Early recognition of patients with community-acquired pneumonia (CAP) at risk of poor outcomes is crucial. However, there is no effective assessment tool for predicting the development of respiratory failure in patients with CAP. Diaphragmatic ultrasonography (DUS) is a novel technique developed for evaluating diaphragmatic function via measurements of the diaphragm thickening fraction (DTF) and diaphragm excursion (DE). This study evaluated the accuracy of DUS in predicting the development of respiratory failure in patients with CAP, as well as the feasibility of its use in the emergency department (ED) setting.

Materials and methods

This was a single-center prospective cohort study. We invited all patients with ED aged ≥ 20 years who were diagnosed with CAP of pneumonia severity index (PSI) SIe diagnosed with CAP of pneumonia severe with respiratory failure or septic shock were excluded. Two emergency physicians performed DUS to obtain DTF and DE measurements. Data were collected to calculate PSI, CURB-65 score, and Infectious Diseases Society of America/American Thoracic Society severity criteria. Study endpoints were taken at the development of respiratory failure or 30 days post-ED presentation. Continuous variables were analyzed using T-tests, while categorical variables were analyzed using chi-square tests. Further logistic regression and receiver operating characteristic curve analyses were performed to examine the ability to predict the development of respiratory failure. Intra- and inter-rater reliability was examined with intraclass correlation coefficients (ICCs).

Results

In this study, 13 of 50 patients with CAP enrolled developed respiratory failure. DTF was found to be an independent predictor (OR: 0.939, p = 0.0416). At the optimal cut-off point of 23.95%, DTF had 69.23% of sensitivity, 83.78% of specificity, 88.57% of negative predictive value, and 80% of accuracy. Intra- and inter-rater analysis demonstrated good consistency (intra-rater ICC 0.817, 0.789; inter-rater ICC 0.774, 0.781).

Conclusion

DUS assessment of DTF may reliably predict the development of respiratory failure in patients with CAP presenting to the ED. Patients with DTF > 23.95% may be considered for outpatient management.

Impact of intubated vs. non-intubated anesthesia on postoperative diaphragmatic function: Results from a prospective observational study

Background: An altered diaphragmatic function was associated with the development of postoperative pulmonary complications following thoracic surgery.

Methods: To evaluate the impact of different anesthetic techniques on postoperative diaphragmatic dysfunction, patients undergoing video-assisted thoracoscopic surgery (VATS) lung biopsy for interstitial lung disease were enrolled in a monocentric observational prospective study. Patients received intubated or non-intubated anesthesia according to risk assessment and preferences following multidisciplinary discussion. Ultrasound measured diaphragmatic excursion (DIA) and Thickening Fraction (TF) were recorded together with arterial blood gases and pulmonary function tests (PFT) immediately before and 12 h after surgery. Pain control and postoperative nausea and vomiting (PONV) were also evaluated.

Results: From February 2019 to September 2020, 41 consecutive patients were enrolled. Five were lost due to difficulties in collecting postoperative data. Of the remaining 36 patients, 25 underwent surgery with a non-intubated anesthesia approach whereas 11 underwent intubated general anesthesia. The two groups had similar baseline characteristics. On the operated side, DIA and TF showed a lower residual postoperative function in the intubated group compared to the non-intubated group (54 vs. 82% of DIA and 36 vs. 97% of TF; p = 0.001 for both). The same was observed on the non-operated side (58 vs. 82% and 62 vs. 94%; p = 0.005 and p = 0.045, respectively, for DIA and TF). No differences were observed between groups in terms of pain control, PONV, gas exchange and PFT.

Conclusion: This study suggests that maintenance of spontaneous breathing during VATS lung biopsy is associated with better diaphragmatic residual function after surgery.

Prevalence of Long COVID-19 Symptoms After Hospital Discharge in Frail and Robust Patients

Background

A motley postacute symptomatology may develop after COVID-19, irrespective of the acute disease severity, age, and comorbidities. Frail individuals have reduced physiological reserves and manifested a worse COVID-19 course, during the acute setting. However, it is still unknown, whether frailty may subtend some long COVID-19 manifestations. We explored the prevalence of long COVID-19 disturbs in COVID-19 survivals.

Methods

This was an observational study. Patients aged 65 years or older were followed-up 1, 3, and 6 months after hospitalization for COVID-19 pneumonia.

Results

A total of 382 patients were enrolled. Frail patients were more malnourished (median Mini Nutritional Assessment Short Form score 8 vs. 9, p = 0.001), at higher risk of sarcopenia [median Strength, Assistance with walking, Rising from a chair, Climbing stairs, and Falls (SARC-F) score 3 vs. 1.5, p = 0.003], and manifested a worse physical performance [median Short Physical Performance Battery (SPPB) score 10 vs. 11, p = 0.0007] than robust individuals, after hospital discharge following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pneumonia. Frailty was significantly associated with: (i) confusion, as a presenting symptom of COVID-19 [odds ratio (OR) 77.84, 95% CI 4.23–1432.49, p = 0.003]; (ii) malnutrition (MNA-SF: adjusted B –5.63, 95% CI –8.39 to –2.87, p < 0.001), risk of sarcopenia (SARC-F: adjusted B 9.11, 95% CI 3.10–15.13, p = 0.003), impaired muscle performance (SPPB: B –3.47, 95% CI –6.33 to –0.61, p = 0.02), complaints in mobility (adjusted OR 1674200.27, 95% CI 4.52–619924741831.25, p = 0.03), in self-care (adjusted OR 553305.56, 95% CI 376.37–813413358.35, p < 0.001), and in performing usual activities of daily living (OR 71.57, 95% CI 2.87–1782.53, p = 0.009) at 1-month follow-up; (iii) dyspnea [modified Medical Research Council (mMRC): B 4.83, 95% CI 1.32–8.33, p = 0.007] and risk of sarcopenia (SARC-F: B 7.12, 95% CI 2.17–12.07, p = 0.005) at 3-month follow-up; and (iv) difficulties in self-care (OR 2746.89, 95% CI 6.44–1172310.83, p = 0.01) at the 6-month follow-up. In a subgroup of patients (78 individuals), the prevalence of frailty increased at the 1-month follow-up compared to baseline (p = 0.009).

Conclusion

The precocious identification of frail COVID-19 survivors, who manifest more motor and respiratory complaints during the follow-up, could improve the long-term management of these COVID-19 sequelae.

Assessment of Diaphragm in Hemiplegic Patients after Stroke with Ultrasound and Its Correlation of Extremity Motor and Balance Function

Background: A variety of functional disorders can be caused after stroke, among which impairment of respiratory function is a frequent and serious complication of stroke patients. The aim of this study was to examine diaphragmatic function after stroke by diaphragm ultrasonography and then to apply to explore its correlation with extremity motor function and balance function of the hemiplegia patients. Methods: This cross-sectional observational study recruited 48 hemiplegic patients after stroke and 20 matched healthy participants. The data of demographic and ultrasonographic assessment of all healthy subjects were recorded, and 45 patients successfully underwent baseline data assessment in the first 48 h following admission, including post-stroke duration, stroke type, hemiplegia side, pipeline feeding, pulmonary infection, ultrasonographic assessment for diaphragm, Fugl−Meyer Motor Function Assessment Scale (FMA Scale), and Berg Balance Scale assessment. Ultrasonographic assessment parameters included diaphragm mobility under quiet and deep breathing, diaphragm thickness at end-inspiratory and end-expiratory, and calculated thickening fraction of the diaphragm. The aim was to analyze the diaphragm function of hemiplegic patients after stroke and to explore its correlation with extremity motor function and balance function. Results: The incidence of diaphragmatic dysfunction under deep breath was 46.67% in 45 hemiplegia patients after stroke at the convalescent phase. The paralyzed hemidiaphragm had major impairments, and the mobility of the hemiplegic diaphragm was significantly reduced during deep breathing (p < 0.05). Moreover, the thickness fraction of hemiplegic side was extremely diminished when contrasted with the healthy control and non-hemiplegic side (p < 0.05). We respectively compared the diaphragm mobility under deep breath on the hemiplegic and non-hemiplegic side of patients with left and right hemiplegia and found there was no significant difference between the hemiplegic side of right and left hemiplegia (p > 0.05), but the non-hemiplegic side of right hemiplegia was significantly weaker than that of left hemiplegia patients (p < 0.05). The diaphragm mobility of stroke patients under quiet breath was positively correlated with age and FMA Scale score (R2 = 0.296, p < 0.05), and significant positive correlations were found between the diaphragm mobility under deep breath and Berg Balance Scale score (R2 = 0.11, p < 0.05), diaphragm thickness at end-inspiratory and FMA Scale score (R2 = 0.152, p < 0.05), and end-expiratory thickness and FMA Scale score (R2 = 0.204, p < 0.05). Conclusions: The mobility and thickness fraction of the hemiplegic diaphragm after stroke by diaphragm ultrasonography were significantly reduced during deep breathing. Diaphragm mobility on bilateral sides of the right hemiplegia patients were reduced during deep breathing. Moreover, the hemiplegic diaphragmatic function was positively correlated with extremity motor and balance function of the hemiplegia patients.

Clinical impact of preoperative diaphragm dysfunction on early outcomes and ventilation function in lung transplant: a single-center retrospective study

Background

Clinical impact of preoperative diaphragm dysfunction on lung transplantation has not been studied. We aimed to evaluate how preoperative diaphragm dysfunction affects clinical outcomes and ventilation function after transplantation.

Methods

We retrospectively enrolled 102 patients. Ultrasound for diagnosis of diaphragm dysfunction was performed on all patients both before and after lung transplantation. The primary outcome was to compare prolonged mechanical ventilation after transplantation according to the preoperative diaphragm dysfunction. Secondary outcomes compared global inhomogeneity index and lung volume after transplantation. Multivariate regression analysis were used to evaluate the association between preoperative diaphragm dysfunction and prolonged mechanical ventilation after transplantation.

Results

A total of 33 patients (32.4%) had preoperative diaphragm dysfunction, and half of them (n = 18) recovered their diaphragm function after transplantation. In contrast, 15 patients (45.5%) showed postoperative diaphragm dysfunction. The ratio of prolonged mechanical ventilation after transplantation was significantly higher in the preoperative diaphragm dysfunction group (p = 0.035). The postoperative durations of mechanical ventilation, intensive care unit and hospital stays were higher in the preoperative diaphragm dysfunction group, respectively (p < 0.05). In the multivariate regression analysis, preoperative diaphragm dysfunction was significantly associated with prolonged mechanical ventilation after transplantation (Odds ratio 2.79, 95% confidence interval 1.07–7.32, p = 0.037). As well, the preoperative diaphragm dysfunction group showed more inhomogeneous ventilation (p < 0.05) and lower total lung volume (p < 0.05) after transplantation. In addition, at 1 month and 3 months after transplantation, FVC was significantly lower in the preoperative diaphragm dysfunction group (p < 0.05).

Conclusions

Preoperative diaphragm dysfunction was associated with prolonged mechanical ventilation after lung transplantation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40560-022-00614-7.

Prolonged Mechanical Ventilation: Outcomes and Management

The number of patients requiring prolonged mechanical ventilation (PMV) is increasing worldwide, placing a burden on healthcare systems. Therefore, investigating the pathophysiology, risk factors, and treatment for PMV is crucial. Various underlying comorbidities have been associated with PMV. The pathophysiology of PMV includes the presence of an abnormal respiratory drive or ventilator-induced diaphragm dysfunction. Numerous studies have demonstrated that ventilator-induced diaphragm dysfunction is related to increases in in-hospital deaths, nosocomial pneumonia, oxidative stress, lung tissue hypoxia, ventilator dependence, and costs. Thus far, the pathophysiologic evidence for PMV has been derived from clinical human studies and experimental studies in animals. Moreover, recent studies have demonstrated the outcome benefits of pharmacological agents and rehabilitative programs for patients requiring PMV. However, methodological limitations affected these studies. Controlled prospective studies with an adequate number of participants are necessary to provide evidence of the mechanism, prognosis, and treatment of PMV. The great epidemiologic impact of PMV and the potential development of treatment make this a key research field.