Mechanical Ventilation–induced Diaphragm Atrophy Strongly Impacts Clinical Outcomes

Inhibition of the expression of TRIM63 alleviates ventilator-induced diaphragmatic dysfunction by modulating the PPARα/PGC-1α pathway

BACKGROUND

Ventilator-induced diaphragmatic dysfunction (VIDD) significantly affects the prognosis of critically ill patients and has attracted considerable attention. Tripartite motif-containing protein 63 (TRIM63) plays a pivotal role in muscle protein degradation and muscle mass regulation. Its overexpression is closely associated with VIDD; however, data on the specific effects of TRIM63 on this pathological process remain insufficient.

OBJECTIVES

The aim of this study is to elucidate the role of TRIM63 in VIDD and to assess the correlation between the TRIM63-peroxisome proliferator activated receptor α (PPARα)/PPAR gamma coactivator (PGC-1α) pathway and mitochondrial function.

METHODS

Specific pathogen-free grade female Wistar rats were divided into four groups: Sham + NS, Sham + MyoMed-205, MV + NS, and MV + MyoMed-205. The inhibitor group received MyoMed-205 to suppress the expression of TRIM63. After the experiment, diaphragmatic contractility, mitochondrial structure and function, oxidative stress levels, autophagy, apoptosis, and the involvement of the PPARα/PGC-1α pathway were evaluated.

RESULTS

Our findings indicated that inhibiting TRIM63 prevented mechanical ventilation (MV)-induced diaphragmatic contractile dysfunction and atrophy. Mechanistically, inhibition of the expression of TRIM63 resulted in significant upregulation of the PPARα and PGC-1α expression levels, improved mitochondrial dynamics, enhanced the mitochondrial membrane potential, and reduced mitophagy and apoptosis. Structurally, inhibition of the expression of TRIM63 ameliorated MV-induced mitochondrial fragmentation, fusion, and fission.

CONCLUSIONS

The upregulated expression of TRIM63 in VIDD exacerbated mitochondrial damage by inhibiting the PPARα/PGC-1α signaling pathway, leading to increased reactive oxygen species, mitophagy, and apoptosis. Inhibition of the expression of TRIM63 enhanced mitochondrial function, decreased mitophagy and apoptosis, and mitigated VIDD. Thus, TRIM63 may serve as a potential target for the prevention and treatment of VIDD.

Flow Index as a Noninvasive Method to Evaluate Inspiratory Effort in Patients on Pressure Support Ventilation

Background: The Flow Index was recently developed as a bedside method based on flow waveforms to assess patient inspiratory effort during invasive mechanical ventilation. The aim of this study is to externally validate the Flow Index by assessing its ability to identify low and high inspiratory effort breaths. Methods: Secondary analysis of a randomized controlled trial. The association between Flow Index and patient inspiratory effort (pressure generated by the respiratory muscles [ΔPmus] and pressure-time product from the start of inspiratory flow [PTPinsp]) was evaluated using linear mixed effects models. The discrimination capacity (area under the curve [AUC]) of the Flow Index to identify low and high inspiratory effort breaths was analyzed. Results: A total of 1,095 breaths from 38 subjects were included in the analysis. Flow Index had moderate discriminatory power in identifying low inspiratory effort breaths (AUC of 0.73 and 0.77 for low inspiratory effort defined with ΔPmus and PTPinsp, respectively). Discriminatory power in identifying high inspiratory effort breaths was low (AUC of 0.68 and 0.65 for ΔPmus and PTPinsp, respectively). Conclusions: Flow Index demonstrated moderate discriminatory power in identifying low inspiratory effort breaths, whereas discriminatory power in identifying high inspiratory effort breaths was low.

Respiratory muscle ultrasound echo characteristics and weaning outcomes in mechanically ventilated patients with sepsis: a prospective observational study

AIM

This study aimed to determine the relationship between changes in the ultrasound echo intensity of respiratory muscles and weaning outcomes in mechanically ventilated patients with sepsis.

METHODS

We prospectively observed patients with sepsis receiving mechanical ventilation admitted to the Department of Critical Care Medicine at our hospital, and categorized them into weaning success (n = 75) and weaning failure (n = 35) groups according to their weaning outcomes. The baseline respiratory muscle echo intensity of the patients was observed, and the relationship between the respiratory muscle ultrasonographic echo characteristics and weaning outcomes was evaluated.

RESULTS

Baseline respiratory muscle echo intensity was significantly higher in the weaning failure group than in the weaning success group. The incidence of respiratory muscle echoes during mechanical ventilation was significantly higher in the weaning failure group than in the weaning success group. The respiratory muscle echo characteristics changed after ICU admission. Increased respiratory muscle echo intensity was detected earlier and more readily in patients with weaning failure than in those with respiratory muscle atrophy, and enhanced respiratory muscle echo was associated with a decrease in the incidence of cumulative weaning success.

CONCLUSION

Mechanically ventilated patients with sepsis with failed weaning had higher respiratory muscle echo intensities than those in the weaning success group. Futhermore, there was an association between the respiratory muscle echo intensity and weaning outcomes.

ARDS Weaning: The Impact of Abnormal Breathing Patterns Detected by Electric Tomography Impedance and Respiratory Mechanics Monitoring

Background: After the improvement of the initial phase of ARDS, when the patients begin spontaneous breathing and weaning from mechanical ventilation, some patients may present abnormal breathing patterns, whose evaluation of the repercussions were poorly studied. This study proposed to evaluate abnormal breathing patterns through the use of electrical impedance tomography (EIT), and clinical, respiratory mechanics, and ventilatory parameters according to the types of weaning from mechanical ventilation. Methods: This was a prospective cohort study of subjects with ARDS who were considered able to be weaned from mechanical ventilation in the clinical-surgical ICU. Weaning types were defined as simple, difficult, and prolonged weaning. EIT, ventilatory, lung mechanics, and clinical data were collected. Data were collected at baseline in a controlled ventilatory mode and, after neuromuscular blocker withdrawal, data were collected after 30 min, 2 h, and 24 h. EIT parameter analysis was performed for ventilation distribution in the lung regions, pendelluft, breath-stacking, reverse-trigger, double-trigger, and asynchrony index. Results: The study included 25 subjects who were divided into 3 groups (9/25 simple, 8/25 difficult, and 8/25 prolonged weaning). The prolonged weaning group showed more delirium, ICU-acquired weakness, stay in ICU, and hospital and ICU mortality. During the change from controlled to spontaneous mode, we observed increased tidal volumes and driving pressures, which were mainly found in the prolonged weaning group when compared with the simple weaning group. The prolonged weaning group showed a higher flow index, more asynchronies during volume-assisted ventilation, a higher incidence of pendelluft, and redistribution of ventilation to posterior regions visualized by EIT. Conclusions: The present study showed abnormal breathing patterns in the prolonged weaning group. The clinical occult findings of abnormal breathing patterns could be monitored, mainly through EIT and with better assessment of pulmonary mechanics.

Impact of Sedation on Ventilator-Induced Diaphragmatic Dysfunction in Extremely Preterm Infants

BACKGROUND

Ventilator-induced diaphragmatic dysfunction is associated with poor patient outcomes. However, the detailed pathophysiology and risk factors underlying the exacerbation of diaphragmatic dysfunction remain unclear. We aimed to evaluate the effect of sedation on diaphragmatic function in extremely preterm infants (EPIs) using ultrasound.

METHODS

A prospective observational study was conducted on 30 EPIs requiring mechanical ventilation within 6 h of birth between July 2020 and September 2023. Diaphragm ultrasound was performed to measure the end-expiratory and end-inspiratory thicknesses of the diaphragm (Tde and Tdi, respectively) and to calculate diaphragm thickening fraction (DTF) after birth and on day 1 of life. Patients receiving continuous fentanyl administration on day 1 were categorized into the sedated group, whereas those not receiving were categorized into the non-sedated group. Changes in Tde, Tdi, and DTF from day 0 to day 1 were compared between groups.

RESULTS

Baseline Tde, Tdi, and DTF did not differ between groups, and both groups showed significant reductions in Tde, Tdi, and DTF from day 0 to day 1. Analysis of covariance after controlling for gestational age and birth weight revealed that sedation significantly affected the change ratios (Tde, -0.343 vs. -0.157, p = 0.038; Tdi, -0.4 vs. -0.169, p = 0.008; DTF, -0.385 vs. -0.194, p = 0.038).

CONCLUSION

In this pilot study, we found that sedation may affect Tde, Tdi, and DTF in ventilated EPIs, and that larger, adequately powered studies are required to validate these preliminary findings.

2024 Year in Review-Pediatric Mechanical Ventilation

Children admitted to the pediatric intensive care unit frequently require invasive mechanical ventilation, a critical intervention central to managing severe respiratory failure and supporting gas exchange. This Year in Review article highlights notable articles on pediatric mechanical ventilation published between 2023 and 2024, curated for clinicians and researchers dedicated to optimizing respiratory care. Key topics include lung-protective ventilation strategies, ventilator liberation practices, assessments of pulmonary function, cardiopulmonary interactions, and the impact of quality improvement initiatives on safety and outcomes, emphasizing the role of structured interventions to reduce preventable adverse events. Together, these studies underscore the complexity of pediatric mechanical ventilation and the importance of individualized, evidence-based strategies in advancing respiratory care for critically ill children.

Transcutaneous Carbon Dioxide Monitoring During Weaning From Mechanical Ventilation in Children: The WeanCO2 Study

INTRODUCTION

Spontaneous breathing trial (SBT) is recommended during weaning from mechanical ventilation (MV), but objective and easy tools lack to identify pediatric weaning failure. We aimed to assess whether changes in estimated arterial CO₂ (PaCO₂) derived from transcutaneous measurements (PTCCO₂) were associated with pediatric weaning failure.

METHODS

Children (age 72 h -18 years) with MV > 12 h were continuously monitored using a transcutaneous sensor to estimate PaCO₂ from skin CO₂ tension (PTCCO₂). Values were recorded during SBT (30 min on positive end-expiratory pressure (PEEP) +5 cmH2O, with pressure support of +5 cmH2O for endotracheal tubes with internal diameter ≤ 3.5 mm), then up to 6 h after extubation. Mean PTCCO2 and PTCCO2 changes during SBT, and after extubation, were retrospectively collected to evaluate their association with SBT failure and extubation failure (reintubation within 48 h).

RESULTS

Eighty children (median [IQR] age 1.1 [0.3; 8.7] years) were included, with 89 SBT (14 failures, 75 successes). Sixty-four patients were extubated following their first SBT, with 10 (16%) extubation failures. PTCCO2 changes were not associated with SBT and extubation failures. Patients who failed extubation had a higher mean PTCCO2 value after extubation as compared to those who were successfully extubated (mean PTCCO2 of 51.8 [46.2; 55.4] vs. 42.3 [37.5; 47.2] mmHg, p = 0.02). The difference between the maximal PTCCO2 value within the 2 h following extubation and the value at extubation were higher in patients who failed extubation (ΔPTCCO2 of 20 [9.1; 26] vs. 6.8 [2.9; 9.7] mmHg, p < 10-2).

CONCLUSION

Early post-extubation increase in estimated PaCO₂ was associated with extubation failure, whereas PTCCO₂ changes during SBT were not.

Thoraco-abdominal biomechanical model and dual-layer control method for soft robotic system with application to respiratory assistance

Introduction

Respiratory dysfunction remains a critical challenge for patients transitioning from intensive care. However, existing assistive devices often fail to address both human-robot dynamic synchronization and patient safety due to the lack of interaction force control. Therefore, this study proposes a human-robot force interaction control strategy by integrating a flexible force sensor, aimed at achieving precise alignment between assistive forces and natural respiratory rhythms.

Methods

In this study, a wearable respiratory assistive robotic system was developed to provide respiratory assistance by applying compressive force to the user's abdomen through soft origami actuators. A thoracoabdominal biomechanical transmission analysis was conducted to reveal the cross-domain force transfer mechanisms. To improve the human-robot adaptability, a dual-layer control architecture for force-pressure coordinated control was designed. Besides, through hardware integration and system building, along with the implementation of interaction force control, the respiratory assistive robot achieves effective respiratory assistance control.

Results

Within the 12-40 breaths/min effective respiratory rate range, PEF, MTV, and MV improved significantly. PEF had a 20.12% average increase, MTV a 19.69% average boost, and MV a 15.5% average rise. Statistically, PEF and MV improvements were highly significant across this range, while MTV was highly significant at 20 breaths/min. Respiratory MV measurements segmented by phase showed that the robot enhanced expiratory function and improved inspiratory function at certain rates within 12-40 breaths/min.

Discussion

The proposed human-robot interaction control system integrates hardware and control systems. Tests on healthy subjects in the effective operating range show that the robotic system can enhance subjects' overall respiratory function and ventilation function, offering a technical reference for future respiratory-assist robot development.

Myokine Secretion Dynamics and Their Role in Critically Ill Patients: A Scoping Review

Background/Objectives: Myokines can modulate organ function and metabolism, offering a protective profile against ICU complications beyond preventing local muscle wasting. This scoping review aims to explore and summarize the evidence regarding the secretion of myokines and their potential local or systemic effects in critically ill patients. Methods: A scoping review following Joana Briggs Institute recommendations was conducted. A systematic search of MEDLINE (Ovid), Embase (Ovid), CENTRAL, CINAHL (EBSCOhost), WoS, and Scopus was conducted from inception to February 2023. We included primary studies evaluating myokine secretion/concentration in critically ill adults undergoing physical rehabilitation interventions. Two independent reviewers performed study selection and data extraction. Results: Seventeen studies published between 2012 and 2023 were included. Most were randomized clinical trials (47%). Physical rehabilitation interventions included electrical muscle stimulation, as well as passive and active mobilization, delivered alone or combined, in single or daily sessions lasting 20-60 min. Twelve studies (70%) evaluated interleukin-6, while interleukin-10, tumour necrosis factor-α, Interleukin-8, and myostatin were also commonly studied. Thirteen studies (76%) reported changes in myokine secretion or gene expression, although no clear concentration change pattern emerged. Myokines involved in muscle protein synthesis and breakdown may protect against muscle waste and weakness. Conclusions: The study of myokine dynamics in critically ill patients highlights the systemic impact of physical rehabilitation. This emerging field has grown in interest over the past decade, offering significant research potential. However, challenges such as study design, small sample sizes, and variability in physical therapy protocols hinder a comprehensive understanding of myokine responses.

Mechanical Power to Predict Ventilator Liberation in Patients With a Tracheostomy

Background: Mechanical power (MP) is useful for predicting the outcomes of attempts to liberate patients from mechanical ventilation. MP is computed based on measured variables derived to determine the power in joules required to breathe while receiving mechanical ventilation. The main objectives of this study were to calculate a cutoff value of MP that would predict successful liberation and to determine the prediction rate of liberation success based on this cutoff value. Methods: This was a single-center retrospective study. Data from 110 tracheostomized subjects receiving mechanical ventilation were analyzed. We divided subjects into two groups based on ventilator liberation outcome. Confounding factors in subject background were adjusted using propensity score matching (PSM). Statistically significant differences in MP at tracheostomy and liberation success between liberation success and failure groups were examined. We calculated the MP cutoff value for successful liberation using the area under the curve of the receiver operating characteristic (ROC) and its corresponding prediction rate of liberation success. Results: The number of subjects in the successful liberation group was 79 and that of the failed liberation group was 31. The MP cutoff value and corresponding prediction rate for liberation success were 256.5 J/min (area under the curve-ROC = 0.839) and 92.2%, respectively. After PSM, the low MP group (n = 36), divided based on the MP cutoff value, had a significantly higher liberation success rate than the high MP group (n = 36), with an odds ratio of 19.95 (CI 3.95, 91.23, P < .001). Conclusion: MP at tracheostomy was a strong predictor of successful ventilator liberation, and the prediction rate of liberation success based on the MP cutoff value was shown to be very high. We recommend that patients with low MP be actively considered for liberation. In contrast, those with high MP should continue weaning while simultaneously making early transfer arrangements if liberation is unsuccessful.

Monitoring and preserving diaphragmatic function in mechanical ventilation

PURPOSE OF REVIEW

This review summarizes the evidence on clinical outcomes related to diaphragm dysfunction, providing an overview on available monitoring tools and strategies for its prevention and treatment.

RECENT FINDINGS

Long-term adverse functional outcomes in intensive care survivors are well documented, especially in patients with prolonged mechanical ventilation. Because diaphragm weakness is highly prevalent and strongly associated with weaning failure, a link between diaphragm weakness and adverse functional outcomes is probable. Mechanisms of critical illness-associated diaphragm weakness are complex and include ventilator-related myotrauma through various pathways (i.e. over-assistance, under-assistance, eccentric, expiratory). Given this potential clinical impact, research on preventive and therapeutic strategies is growing including the development of ventilation strategies aiming at protecting both the lung and the diaphragm. Phrenic nerve stimulation and specific rehabilitation strategies also appear promising.

SUMMARY

Diaphragm dysfunction is associated with adverse clinical outcomes in ventilated patients; therefore, their inspiratory effort and function should be monitored. Whenever possible, and without compromising lung protection, moderate inspiratory effort should be targeted. Phrenic nerve stimulation and specific rehabilitation strategies are promising to prevent and treat diaphragm dysfunction, but further evidence is needed before widespread implementation.

Assessment of diaphragmatic thickness as a predictor for intubation in pneumonia patients

Pneumonia, one of the major contributors to morbidity and mortality globally, often leads to serious complications such as respiratory failure. Diaphragmatic dysfunction, detected through ultrasound, may predict the need for intubation in patients with pneumonia. This study aimed to evaluate the roles of diaphragmatic thickness fraction (DTF) and diaphragmatic excursion (DE) as predictors of intubation in pneumonia patients. This follow-up cohort study involved 53 participants diagnosed with pneumonia. Diaphragmatic ultrasonography was performed to measure DTF and DE within 24 hours of admission. The mean age of the patients was 51.8±20.4 years, with 66% being male. Diabetes mellitus (DM) (p=0.000) and hypertension (HTN) (p=0.003) were significantly associated with the need for intubation. DE was significantly correlated with intubation (p=0.001). At a cut-off of 2.9 cm, DE demonstrated 100% sensitivity and 56% specificity for predicting intubation. DTF exhibited 92% sensitivity and 60% specificity at a cut-off of 0.52, with a positive predictive value of 85% and a negative predictive value of 54%. Diaphragmatic parameters, particularly DE and DTF, are significant predictors of intubation in pneumonia patients. Comorbidities such as DM and HTN also play a critical role, underscoring the importance of early identification of high-risk patients for timely intervention.

Prediction of Weaning Outcomes in Mechanically Ventilated Patients Using Diaphragmatic Excursion With Tissue Doppler Imaging Variables of the Diaphragm

Background: Diaphragmatic excursion is a crucial predictor of extubation outcomes in subjects on mechanical ventilation. However, its measurement can be influenced by various factors, which leads to inconsistent optimal thresholds and accuracy. Tissue Doppler imaging variables of the diaphragm have been established as reliable indicators for predicting extubation outcomes. This study aimed to assess the predictive ability of combining diaphragmatic excursion with tissue Doppler imaging variables of the diaphragm in subjects on mechanical ventilation. Methods: This prospective observational study was conducted from April 2023 to April 2024, eligible subjects who underwent mechanical ventilation for > 48 h and successfully completed a 30-min spontaneous breathing test in the ICU of our center. Diaphragmatic excursion and tissue Doppler imaging variables (including peak contraction velocity, peak relaxation velocity, maximal contraction rate, and maximal relaxation rate) were assessed immediately after a 30-min spontaneous breathing trial. The subjects were categorized into successful extubation and failed extubation groups based on their extubation outcomes. Differences in diaphragmatic ultrasound variables between these groups were analyzed. Results: The study included 63 subjects in the successful extubation group and 28 subjects in the failed extubation group. The area under the receiver operating characteristic curve for diaphragmatic excursion in predicting successful extubation was determined as 0.79 (95% CI, 0.69 ∼ 0.89), with a sensitivity of 82.5% and a specificity of 75.0%. The combined area under the receiver operating characteristic curve for diaphragmatic excursion and tissue Doppler imaging variables (including peak contraction velocity and maximal relaxation rate) in predicting successful extubation was determined as 0.94 (95% CI, 0.88 ∼ 0.99), with a sensitivity of 92.1% and a specificity of 89.3%. Conclusions: Combining diaphragmatic excursion with tissue Doppler imaging variables of the diaphragm enhanced the prediction of extubation outcomes in the subjects on mechanical ventilation compared with diaphragmatic excursion alone.

POCUS in the PICU: A Narrative Review of Evidence-Based Bedside Ultrasound Techniques Ready for Prime-Time in Pediatric Critical Care

Point-of-care ultrasound (POCUS) is an accessible technology that can identify and treat life-threatening pathology in real time without exposing children to ionizing radiation. We aim to review current evidence supporting the use of POCUS by pediatric intensivists with novice-level experience with bedside ultrasound. Current evidence supports the universal adoption of POCUS-guided internal jugular venous catheter placement and arterial line placement by pediatric critical care physicians. Focused cardiac ultrasound performed by PICU physicians who have completed appropriate training with quality assurance measures in place can identify life-threatening cardiac pathology in most children and important physiological changes in children with septic shock. POCUS of the lungs, pleural space, and diaphragm have great potential to provide valuable information at the bedside after validation of these techniques for use in the PICU with additional research. Based on currently available evidence, a generalizable and attainable POCUS educational platform for pediatric intensivists should include training in vascular access techniques and focused cardiac examination. A POCUS educational program should strive to establish credentialing and quality assurance programs that can be expanded when additional research validates the adoption of additional POCUS techniques by pediatric intensive care physicians.

Role of diaphragmatic dysfunction in extubation failure among patients at high risk of reintubation: A prospective cohort study

PURPOSE

This study aims to evaluate the role of diaphragmatic dysfunction in extubation failure among patients at high risk of reintubation.

MATERIAL AND METHODS

This prospective cohort study was carried out at a intensive care unit in China. Adult patients who had been intubated for more than 24 h and ready for extubation were included in the study if they exhibited a high risk of extubation failure. Diaphragm dysfunction was defined as a diaphragmatic thickening fraction <30 % or diaphragmatic excursion <10 mm. The primary outcome was defined as extubation failure, which includes either reintubation or death within the initial 7 days following extubation.

RESULTS

Out of the 113 patients, 27 (23.89 %) experienced extubation failure, with diaphragm dysfunction diagnosed in 63 (55.75 %) individuals. Patients who failed extubation were significantly more likely to have diaphragm dysfunction (85.19 % vs. 46.51 %, p < 0.01). In the Cox-proportional hazards regression analysis, diaphragm dysfunction and the Medical Research Council score were found to be associated with extubation failure. The adjusted hazard ratios were 4.56 [95 % CI: 1.56-13.33] and 0.93 [95 % CI: 0.88-0.99]. Both variables were closely correlated with extubation failure showing statistical significance.

CONCLUSION

Diaphragm dysfunction could contribute to an elevated extubation failure rate.

Advancements in imaging techniques for monitoring the respiratory muscles

This review highlights the latest advancements in imaging techniques for monitoring respiratory muscles in critically ill patients. At the bedside, conventional ultrasound has been widely adopted to measure diaphragm thickness, thickening and excursion. It has also been used to assess extradiaphragmatic respiratory muscles, including parasternal intercostal and abdominal muscles. Advanced ultrasound-derived techniques have expanded its applications, enabling the evaluation of tissue velocity (tissue Doppler imaging), stiffness (shear wave elastography), and local tissue displacement (speckle tracking). Facility-based imaging modalities such as magnetic resonance imaging and chest tomography provide complementary insights into respiratory muscles structure and function, offering valuable information for evaluating the effects of therapeutic interventions. Finally, imaging techniques have emerged as valuable tools for evaluating the metabolic demands of respiratory muscles, with advanced methods such as positron emission tomography and contrast-enhanced ultrasound showing significant potential.

Debate on the Role of Eccentric Contraction of the Diaphragm: Is It Always Harmful?

The diaphragm is the primary muscle involved in the ventilatory pump, making it a vital component in mechanical ventilation. Various factors in patients who require mechanical ventilation can lead to the deterioration of the diaphragm, which is associated with increased mortality. This deterioration can arise from either excessive or insufficient support due to improper adjustment of ventilation programming variables. It is essential for healthcare professionals to make appropriate adjustments to these variables to prevent myotrauma, which negatively impacts muscle structure and function. One recognized cause of muscle injury is eccentric work of the diaphragm, which occurs when muscle contractions continue after the expiratory valve has opened. Current evidence suggests that these eccentric contractions during mechanical ventilation can be harmful. This brief review highlights and analyzes the existing evidence and offers our clinical perspective on the importance of properly adjusting ventilation programming variables, as well as the potential negative effects of eccentric diaphragm contractions in routine clinical practice.

Assessing agreement among non-invasive indicators for inspiratory effort during pressure support ventilation

Background

During pressure support ventilation (PSV), the accuracy of non-invasive indicators in diagnosing high or low inspiratory effort has been validated. However, the correlation and agreement of these indicators remain unclear. This study aims to investigate the correlation and agreement among non-invasive inspiratory effort indicators, and to compare characteristics of inspiratory effort in neurocritical and non-neurocritical patients.

Methods

This was a single-centre prospective observational study. We collected three non-invasive inspiratory effort indicators, pressure muscular index (PMI), the maximal negative swing of airway pressure during expiratory occlusion (ΔPocc), and the airway occlusion pressure during the first 100ms (P0.1). Cutoff values for these indicators derived from esophageal pressure-time product (PTPmus) were chosen for this study. The correlation and agreement of these indicators were analyzed using Spearman's rank correlation test and linear weighted Kappa analysis. Characteristics of PSV settings and inspiratory effort in neurocritical and non-neurocritical patients were compared.

Results

Ninety-seven patients were enrolled in this study. Correlation analysis showed a moderate correlation between PMI and ΔPocc (rho = -0.524, p < 0.001), ΔPocc and P0.1 (rho = 0.588, p < 0.001), while no correlation between PMI and P0.1 (rho = -0.140, p = 0.172). There was a moderate agreement between ΔPocc and P0.1 (k = 0.459, p < 0.001), a fair agreement between PMI and ΔPocc (k = 0.362, p < 0.001), but no agreement between PMI and P0.1 (k = 0.134, p = 0.072). The correlation of these indicators was similar in neurocritical patients compared with non-neurocritical patients, but agreement was poor.

Conclusion

The study showed that PMI and ΔPocc had moderate correlation and fair agreement, ΔPocc and P0.1 had moderate correlation and agreement, while PMI and P0.1 had no correlation and agreement.

High Respiratory and Cardiac Drive Exacerbate Secondary Lung Injury in Patients With Critical Illness

The high respiratory and cardiac drive is essential to the host-organ unregulated response. When a primary disease and an unregulated secondary response are uncontrolled, the patient may present in a high respiratory and cardiac drive state. High respiratory drive can cause damage to the lungs, pulmonary circulation, and diaphragm, while high cardiac drive can lead to fluid leakage and infiltration as well as pulmonary interstitial edema. A "respiratory and cardiac dual high drive" state may be a sign of an unregulated response and can lead to secondary lung injury through the increase of transvascular pressure and pulmonary microcirculation injury. Ultrasound examination of the lung, heart, and diaphragm is important when evaluating the phenotype of high respiratory drive in critically ill patients. Ultrasound assessment can guide sedation, analgesia, and antistress treatment and reduce the risk of high respiratory and cardiac drive-induced lung injury in these patients.

Similar Weaning Success Rate with High-Intensity and Sham Inspiratory Muscle Training: A Randomized Controlled Trial (IMweanT)

Rationale: Inspiratory muscle training (IMT) improves respiratory muscle function in patients with weaning difficulties. IMT protocols involve performing daily sets of breaths against external loads. However, the impact of IMT on weaning outcomes while incorporating sham control interventions remains unclear. Objectives: To compare the effects of a high-intensity IMT (Hi-IMT) intervention with a sham low-intensity (Lo-IMT) control group on weaning outcomes and respiratory muscle and pulmonary function 28 days after inclusion in patients with weaning difficulties. Methods: Both groups underwent daily IMT sessions until successful weaning or a maximum of 28 days. The Hi-IMT group (n = 44; 61% male; aged 57 ± 15 yr) performed maximal inspirations initiated from residual volume against an external load representing 30-50% of maximal inspiratory pressure (PImax), and the control group (n = 46; 52% male; aged 60 ± 12 yr) performed maximal inspirations against a load ⩽10% PImax. Measurements and Main Results: Training adherence (completed/planned sessions) was comparable between the groups (Hi-IMT, 77 ± 20%; Lo-IMT, 72 ± 17%; P = 0.25). Weaning success (64% Hi-IMT and 76% Lo-IMT; P = 0.43) and weaning duration (Hi-IMT, 45 ± 48 d; Lo-IMT, 37 ± 26 d; P = 0.33) were similar between groups. Both groups similarly improved PImax (Hi-IMT, +15 cm H2O [95% confidence interval (CI), 9, 20]; Lo-IMT, +14 cm H2O [95% CI, 9, 19]; P = 0.72). FVC improved more in the Hi-IMT group than in the Lo-IMT group (Hi-IMT, +0.33 L [95% CI, 0.22, 0.43]; Lo-IMT, +0.16 L [95% CI, 0.07, 0.25]; P = 0.04). Conclusions: Both high-intensity IMT and sham low-intensity IMT, with high adherence to the protocol, resulted in similar weaning success rates and pronounced improvements in maximal inspiratory muscle strength. Clinical trial registered with www.clinicaltrials.gov (NCT03240263).

Diaphragm thickness and physical performance in regular smokers and non-smokers: A pilot study

BACKGROUND

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

Research on the Correlation between Balance Function and Core Muscles in Patients With Adolescent Idiopathic Scoliosis

OBJECTIVE

This study aimed to explore the correlation between balance function and core muscle activation in patients with adolescent idiopathic scoliosis (AIS), compared to healthy individuals.

METHODS

A total of 24 AIS patients and 25 healthy controls were recruited. The limits of stability (LOS) test were conducted to assess balance function, while surface electromyography was used to measure the activity of core muscles, including the internal oblique, external oblique, and multifidus. Diaphragm thickness was measured using ultrasound during different postural tasks. Center of pressure (COP) displacement and trunk inclination distance were also recorded during the LOS test.

RESULTS

AIS patients showed significantly greater activation of superficial core muscles, such as the internal and external oblique muscles, compared to the control group (p < 0.05). Diaphragm activation was lower in AIS patients during balance tasks (p < 0.01). Although no significant difference was observed in COP displacement between the groups, trunk inclination was significantly greater in the AIS group during certain tasks (p < 0.05).

CONCLUSION

These findings suggest distinct postural control patterns in AIS patients, highlighting the importance of targeted interventions to improve balance and core muscle function in this population.

Predicting Mortality in Sepsis-Associated Acute Respiratory Distress Syndrome: A Machine Learning Approach Using the MIMIC-III Database

BackgroundTo develop and validate a mortality prediction model for patients with sepsis-associated Acute Respiratory Distress Syndrome (ARDS).MethodsThis retrospective cohort study included 2466 patients diagnosed with sepsis and ARDS within 24 h of ICU admission. Demographic, clinical, and laboratory parameters were extracted from Medical Information Mart for Intensive Care III (MIMIC-III) database. Feature selection was performed using the Boruta algorithm, followed by the construction of seven ML models: logistic regression, Naive Bayes, k-nearest neighbor, support vector machine, decision tree, Random Forest, and extreme gradient boosting. Model performance was evaluated using the area under the receiver operating characteristic curve, accuracy, sensitivity, specificity, positive predictive value, and negative predictive value.ResultsThe study identified 24 variables significantly associated with mortality. The optimal ML model, a Random Forest model, demonstrated an AUC of 0.8015 in the test set, with high accuracy and specificity. The model highlighted the importance of blood urea nitrogen, age, urine output, Simplified Acute Physiology Score II, and albumin levels in predicting mortality.ConclusionsThe model's superior predictive performance underscores the potential for integrating advanced analytics into clinical decision-making processes, potentially improving patient outcomes and resource allocation in critical care settings.

Pushing and guiding me towards home; patients' perspectives of person-centred physiotherapy in Intensive Care

PURPOSE

Person-centred physiotherapy in Intensive Care Units (ICU) supports patients' early rehabilitation. Yet little is known about the activity required to enable person-centred physiotherapy in this setting. This study explores the experiences and interpretations of people who received physiotherapy.

METHODS

A qualitative study using Interpretative Phenomenological Analysis was conducted. Eight participants, recruited from a Ventilation Unit in Northwest England, were interviewed. Data were transcribed and managed using NVivo 12 software.

RESULTS

Participants described being "pushed" and guided by physiotherapists. The "emotional" pushing through motivation and encouragement, and "physical" pushing through setting goals, were perceived as person-centred activities, despite physiotherapists initially directing them. Other important aspects of individualised care were feeling safe and understanding how their body had changed.

CONCLUSIONS

Patients viewed physiotherapist led rehabilitation in ICU as being person-centred, despite the lack of collaboration during early recovery, because they were too ill. Models of person-centred physiotherapy could be made more applicable to clinical settings by fully integrating the patient perspective.

Weakness acquired in the cardiac intensive care unit: still the elephant in the room?

Over the past two decades, the cardiac critical care population has shifted to increasingly comorbid and elderly patients often presenting with nonprimary cardiac conditions that exacerbate underlying advanced cardiac disease. Consequently, the modern cardiac intensive care unit (CICU) patient has poor outcome regardless of left ventricular ejection fraction. Importantly, delayed liberation from organ support, independent from premorbid health status and admission severity of illness, has been associated with increased morbidity and mortality up to years post-general critical care. Although a constellation of several acquired morbidities is at play, the most prominent enactor of poor long-term outcome in this population appears to be intensive care unit acquired weakness. Although the specific burden of ICU-acquired morbidities in CICU patients is yet to be clearly defined, it seems unfathomable that patients will not accrue some sort of ICU-related morbidity. There is hence an urgent need to better establish the exact benefit and cost of resource-intensive strategies in both short- and long-term survival of the CICU patient. Consequent and standardized documentation of admission comorbidities, severity of illness indicators, relevant ICU-related complications including weakness, and long-term post-ICU morbidity outcomes can help our understanding of the disease continuum and how to better care for the CICU survivor and their families and caregivers. Given increasing budgetary pressure on healthcare systems worldwide, interventions targeting CICU patients should focus on improving patient-centred long-term outcomes in a cost-effective manner. It will require a holistic and transmural continuity of care model to meet the challenges associated with treating critically ill cardiac patients in the future.

Respiratory effort in mechanical ventilation weaning Prediction: An observational, case-control study

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

IMPLICATIONS FOR CLINICAL PRACTICE

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

Ultrasonographic Assessment of Diaphragm Function to Predict Need for Mechanical Ventilation and its Liberation in Patients with Neuromuscular Disorders: An Observational Cohort Pilot Study

BACKGROUND

Management of assisted ventilation and determining the optimal timing for discontinuation presents a significant clinical obstacle in patients affected by neuromuscular (NM) diseases. This study aimed to evaluate the efficacy of ultrasound in appraising diaphragmatic function for predicting the necessity of intubation and determining the opportune moment to discontinue mechanical ventilation (MV) in patients with NM disorders.

METHODS

The study was conducted in adult patients with NM diseases requiring inpatient care in the high-dependency neurology ward and the intensive care unit. Ultrasonographic assessment of diaphragmatic excursion (DE) and diaphragmatic thickness fraction (DTF) was conducted at the patient's bedside every 48 h for ventilated patients and every 72 h for nonventilated patients until they were weaned from the ventilator or discharged home. Qualitative data are expressed as percentages or numbers, and quantitative data are represented as mean ± standard deviation. Unpaired t-tests were employed to compare continuous variables, and χ2 tests were used for categorical variables. Contingency table analysis was used to compute relative risks in comparing the baseline DE and DTF with the sequential changes in these values.

RESULTS

In cases in which the baseline left DE measured less than 1 cm, the relative risk for the requirement of ventilation was 2.5 times higher, with a confidence interval of 0.62-0.99 (P = 0.19). Notably, a bilateral reduction in DE within the initial 48 h of admission was identified as predictive of need for intubation. When comparing ventilated and nonventilated patients, it was observed that the mean DE values for the left and right sides in ventilated patients (0.74 and 0.79) were significantly lower than those in nonventilated patients (1.3 and 1.66), with corresponding P values of 0.05 and 0.01, respectively. Furthermore, a decline in right DE by more than 50% within 72 h of admission presented a relative risk of 3.3 for the necessity of ventilation, with a confidence interval of 1.29-8.59 (P = 0.01). Duration of ventilation ranged from 2 to 45 days, with an average of 13.14 days, whereas the mean ventilator-free days recorded was 13.57. Notably, a sequential increase in bilateral DE correlated with an extended duration of ventilator-free days.

CONCLUSIONS

The presence of a baseline left DE of less than 1 cm, a consecutive decrease in DE measurements within 48 h, and a comparative reduction in right DE of more than 50% within the initial 3 days are indicators associated with the requirement for MV in patients with NM disease. Furthermore, the upward trajectory of DE in mechanically ventilated patients is linked to an increased number of days free from ventilator support, suggesting its potential to forecast earlier weaning.

Assessment of Respiratory Muscles, Lung Parenchyma, and Cardiac Function by Ultrasound for Predicting Weaning Failure in Critically Ill Adults: A Prospective Observational Study

OBJECTIVES

The parasternal intercostal muscle activity, a marker of accessory muscle usage, is found to correlate inversely with the pressure-generating capacity of the diaphragm and level of support of mechanical ventilation. The primary objective of our study was to determine whether the parasternal intercostal muscle thickening fraction (PMTF) measured by ultrasonography can predict weaning. We also evaluated whether addition of lung ultrasound score and echocardiographic assessment can add on to predicting weaning failure.

METHODS

This prospective observational study conducted in a mixed medical-surgical intensive care unit, included 60 adult patients who were eligible for a spontaneous breathing trial (SBT) after being invasively mechanically ventilated for more than 48 hours. Ultrasound of respiratory muscles, lung parenchyma, and echocardiographic assessment were performed before and after 120 minutes of SBT. Parasternal intercostal muscles were imaged with a high frequency linear probe on the right second intercostal space 5 cm lateral to the sternal margin. PMTF was calculated as (maximum-minimum thickness)/minimum thickness.

RESULTS

Among 60 patients, SBT failure was seen in 11 patients and extubation failed in 8 patients. PMTF (%) was significantly higher in the weaning failure group (13.33 [8.33-19.05]) as compared to patients with successful weaning (6.67 [6.06-11.54]). Diaphragmatic thickening fraction (DTF) correlated inversely to PMTF in patients with weaning failure. A pre-SBT PMTF cut-off of ≥7.7% and post-SBT cut-off of ≥15.38% were good predictors of weaning failure and extubation failure, respectively.

CONCLUSIONS

PMTF has good discriminatory power to predict weaning outcomes (area under the receiver operating characteristic curve: 0.74 [0.59-0.88]). Pre-SBT PMTF had similar power as DTF to predict weaning failure.

Comparison of programmed sedation care with conventional care in patients receiving mechanical ventilation for acute respiratory failure

OBJECTIVE

The aim of this study is to evaluate the effectiveness of planned sedation therapy in comparison to standard care for patients receiving mechanical ventilation for acute respiratory failure (ARF).

METHOD

The research included a total of sixty individuals who underwent mechanical ventilation for acute respiratory failure (ARF). Utilizing the random number table method, these patients were randomized at random to either the planned sedation care group (Group PSC) or the conventional care group (Group C). The objective was to assess and contrast the impact of treatment on the two groups. Significantly shorter durations of mechanical ventilation, sedative use, ICU therapy, length of stay, incidence of delirium, and adverse events were observed in Group PSC compared with Group C (P < 0.05). A higher 1-month survival rate following mechanical ventilation, a higher post-intervention forced expiratory volume in one second (FEV1) as a percentage of the expected value, a higher post-intervention forced vital capacity (FVC), and a higher patient family care satisfaction rate were observed in Group PSC compared to Group C (P < 0.05).

CONCLUSION

The scheduled administration of sedative therapy in patients receiving mechanical ventilation for acute respiratory failure (ARF) offers significant, reliable, and effective therapeutic benefits.

Proportional modes to hasten weaning

PURPOSE OF REVIEW

The purpose of this review is to examine the current state of the evidence, including several recent systematic reviews and meta-analyses, to determine if proportional modes of ventilation have the potential to hasten weaning from mechanical ventilation for adult critically ill patients, compared to pressure support ventilation (PSV), the current standard of care during the recovery and weaning phases of mechanical ventilation.

RECENT FINDINGS

Proportional assist ventilation (PAV) and neurally adjusted ventilatory assist (NAVA) are two commercially available proportional modes that have been studied in randomized controlled trials (RCTs). Although several feasibility studies were not powered to detect differences in clinical outcomes, emerging evidence suggests that both PAV and NAVA may reduce duration of mechanical ventilation, intensive care unit (ICU) length of stay, and hospital mortality compared to PSV, as shown in some small, primarily single-centre studies. Recent meta-analyses suggest that PAV shortens duration of mechanical ventilation and improves weaning success rate, and NAVA may reduce ICU and hospital mortality.

SUMMARY

The current state of the evidence suggests that proportional modes may hasten weaning from mechanical ventilation, but larger, multicentre RCTS are needed to confirm these preliminary findings.

Effects of Expiratory Muscle Strength Training on Swallowing in Survivors of Critical Illness: A Protocol for a Systematic Review and Meta-Analysis

Background and Aims

Post Extubation Dysphagia (PED) is a common consequence of mechanical ventilation. Muscular weakness and atrophy are potential causes. Expiratory Muscle Strength Training (EMST) is a technique whereby a subject exhales against a resistance, strengthening the muscles of expiration. There is evidence that EMST causes activation and hypertrophy of the muscles of swallowing, with clinical evidence that it improves swallowing in certain populations. The aim of this systematic review is to collate the existing literature concerning evaluation of swallowing after extubation, and whether EMST positively affects these measures.

Methods

We will perform a systematic review of the literature by searching electronic databases (Pubmed, Medline, EMBASE, and the Cochrane Library), for articles where EMST has been performed (alone or in conjunction with inspiratory muscle training), in patients who have been liberated from a period of mechanical ventilation. We will identify studies that evaluate swallowing after extubation, listing the methods used to evaluate swallowing and data will be extracted from studies evaluating the impact EMST has on these measures.

Results

We will undertake meta-analysis if data permits. Risk of bias will be assessed using the Risk of Bias 2 tool or the Newcastle Ottawa Score for randomized and non-randomized trials. We will use The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to assess the quality of evidence.

Conclusion

The results of this systematic review will enable us to assess the current literature on the use of EMST in critical care, and whether the intervention improves swallowing and respiratory outcomes. Trial Registration: PROSPERO registration: 42023444479.

Diaphragm dysfunction: how to diagnose and how to treat?

The diaphragm, crucial for respiratory function, is susceptible to dysfunction due to various pathologies that can affect the nervous system, neuromuscular junction or the muscle itself. Diaphragmatic dysfunction presents with symptoms ranging from exertional dyspnoea to respiratory failure, significantly impacting patients' quality of life. Diagnosis involves clinical evaluation complemented by imaging and pulmonary function tests. Chest radiography, fluoroscopy, and ultrasonography are pivotal in assessing diaphragmatic movement and excursion, offering varying sensitivities and specificities based on the type and severity of dysfunction. Ultrasonography emerges as a noninvasive bedside tool with high sensitivity and specificity, measuring diaphragm thickness, thickening fraction, and excursion, and enabling monitoring of disease progression and response to treatment over time. Treatment strategies depend on the underlying aetiology and severity, ranging from conservative management to interventions such as surgical plication or diaphragmatic pacing. Ventilatory support, particularly noninvasive ventilation, plays a pivotal role in treatment, enhancing lung function and patient outcomes across unilateral and bilateral dysfunction. Despite advances in diagnostic techniques, awareness and systematic evaluation of diaphragmatic function remain inconsistent across clinical settings. This review consolidates the current understanding of diaphragmatic dysfunction, highlighting diagnostic modalities and treatment options to facilitate early recognition and management of this entity.

Review of Point-of-Care Diaphragmatic Ultrasound in Emergency Medicine: Background, Techniques, Achieving Competency, Research, and Recommendations

ABSTRACT

The diaphragm is the major muscle of inspiration accounting for approximately 70% of the inspired tidal volume. Point-of-care diaphragmatic ultrasound offers the ability to quantitatively assess diaphragmatic function, perform serial evaluations over time, and visualize structures above and below the diaphragm. Although interest in point-of-care ultrasound (POCUS) of the diaphragm is developing in the emergency medicine, assessment of the diaphragm and its function is not recognized as a core application by national organizations or expert guidelines. As a result, it is infrequently performed, and its potential value in research or clinical practice may not be fully appreciated. The purpose of this review is to describe the developmental aspects of the diaphragm as it pertains to POCUS, discuss the POCUS techniques for evaluating diaphragmatic function, address competency acquisition in this POCUS application, summarize relevant research in the ED, and provide a summary of recommendations for further research and clinical utilization of POCUS in diaphragm evaluation.

Entacapone alleviates muscle atrophy by modulating oxidative stress, proteolysis, and lipid aggregation in multiple mice models

Background

Skeletal muscle atrophy significantly affects quality of life and has socio-economic and health implications. This study evaluates the effects of entacapone (ENT) on skeletal muscle atrophy linked with oxidative stress and proteolysis.

Methods

C2C12 cells were treated with dexamethasone (Dex) to simulate muscle atrophy. Four murine models were employed: diaphragm atrophy from mechanical ventilation, Dex-induced atrophy, lipopolysaccharide (LPS)-induced atrophy, and hyperlipidemia-induced atrophy. Each model utilized entacapone (10 mg/kg), with sample sizes: Control (9), MV (11), MV + ENT (5) for diaphragm atrophy; Control (4), Dex (4), Dex + ENT (5) for Dex model; Control (4), LPS (4), LPS + ENT (5) for LPS model; and similar for hyperlipidemia. Measurements included muscle strength, myofiber cross-sectional area (CSA), proteolysis, oxidative stress markers [uperoxide dismutase 1 (SOD1), uperoxide dismutase 2 (SOD2), 4-hydroxynonenal (4-HNE)], and lipid levels.

Results

Our findings confirm Dex-induced muscle atrophy, evidenced by increased expression of muscle atrophy-associated proteins, including Atrogin-1 and Murf-1, along with decreased diameter of C2C12 myotubes. Atrogin-1 levels rose by 660.6% (p < 0.05) in the Dex group compared to control, while entacapone reduced Atrogin-1 by 84.4% (p < 0.05). Similarly, Murf-1 levels increased by 365% (p < 0.05) in the Dex group and were decreased by 89.5% (p < 0.05) with entacapone. Dexamethasone exposure induces oxidative stress, evidenced by the upregulation of oxidative stress-related proteins Sod1, Sod2, and 4-HNE. Entacapone significantly reduced the levels of these oxidative stress markers, enhancing GSH-PX content by 385.6% (p < 0.05) compared to the Dex-treated group. Additionally, ENT effectively reduced the Dex-induced increase in MDA content by 63.98% (p < 0.05). Furthermore, entacapone effectively prevents the decline in diaphragm muscle strength and myofiber CSA in mice. It also mitigates diaphragm oxidative stress and protein hydrolysis. Additionally, entacapone exhibits the ability to attenuate lipid accumulation in the gastrocnemius muscle of hyperlipidemic mice and alleviate the reduction in muscle fiber CSA.

Conclusion

Our findings suggest that entacapone is a promising therapeutic candidate for muscle atrophy, functioning through the reduction of oxidative stress, proteolysis, and lipid aggregation. Future research should explore the underlying mechanisms and potential clinical applications of entacapone in muscle-wasting conditions.

Bedside Assessment of the Respiratory System During Invasive Mechanical Ventilation

Assessing the respiratory system of a patient receiving mechanical ventilation is complex. We provide an overview of an approach at the bedside underpinned by physiology. We discuss the importance of distinguishing between extensive and intensive ventilatory variables. We outline methods to evaluate both passive patients and those making spontaneous respiratory efforts during assisted ventilation. We believe a comprehensive assessment can influence setting mechanical ventilatory support to achieve lung and diaphragm protective ventilation.

Rehabilitation effects of acupuncture on the diaphragmatic dysfunction in respiratory insufficiency: A systematic review and meta-analysis

INTRODUCTION

Mechanical ventilation after respiratory insufficiency can induce diaphragm dysfunction through various hypothesized mechanisms. In this study, we evaluated the rehabilitative effect of acupuncture on diaphragm function in patients with respiratory insufficiency using meta-analysis and summarised the rules of acupoints through association rules analysis.

METHODS

Articles (published from January 2000 to February 2024) were retrieved from the following databases: PubMed, Cochrane Library, Embase, Web of Science, CNKI, VIP, SinoMed, and Wanfang. Two researchers conducted literature selection, data extraction, and statistical analysis independently. The risk of bias was assessed utilizing the Physical Therapy Evidence Database (PEDro) scale. The meta-analysis was performed with RevMan 5.4 software, and the quality of each outcome evidence was assessed via the online software GRADEpro GDT. The regularity of acupoint selection was summarized using association rules analysis. This study is registered on PROSPERO, number CRD42024526705.

RESULTS

Eleven articles were eventually included, all of which were of low to moderate quality. Results of the meta-analysis showed a significant increase in diaphragmatic thickening fraction (MD 3.40 [1.52, 5.27]) and diaphragmatic excursion (MD 0.95 [0.58, 1.31]) in patients with respiratory insufficiency after acupuncture treatment. Also, OI (MD 28.52 [15.93, 41.11]) and PaO2 (MD 7.18 [2.22, 12.13]) were significantly elevated and PaCO2 (MD -6.94 [-12.30, -1.59]) was decreased. Mechanical ventilation time (MD-1.86 [-2.28, -1.45]) was also significantly improved. The overall quality of the outcome evidence is deemed moderate. Association rules analysis showed that ST36, RN4, RN6, and others are core acupoints for the treatment of diaphragmatic dysfunction in patients with respiratory insufficiency by acupuncture.

CONCLUSION

Acupuncture shows potential in the rehabilitation of patients with respiratory insufficiency and may serve as a complementary and alternative therapy for related conditions. We suggest the use of ST36 as a core acupoint, in combination with other acupoints. Due to the potential publication bias and high heterogeneity of the current data, further high-quality RCTs are needed to confirm these findings.

Diaphragm pacing compared with mechanical ventilation in patients with chronic respiratory failure caused by diaphragmatic dysfunction: a systematic review and meta-analysis

BACKGROUND

The effectiveness of diaphragmatic electrical stimulation (DES) compared to mechanical ventilation (MV) in improving clinical outcomes such as quality-of-life (QOL) and hospital stay remains inconsistent.

METHODS

We conducted a systematic review and meta-analysis by searching PubMed, Scopus, Google Scholar, LILACS, and IEEE Xplore. We included comparative studies (randomized controlled trials and observational studies) of DES administered via the phrenic nerve or intramuscular electrodes, compared with MV in adults with diaphragmatic paralysis or paresis. Two authors independently extracted data and assessed bias, with discrepancies resolved by a senior author. Results were pooled using the inverse variance method.

RESULTS

Out of 1,290 articles, nine were included in the systematic review, totaling 852 subjects. In spinal cord injury (SCI), one study reported lower mortality with DES, while three found no difference compared to MV. In these patients, DES was associated with shorter hospital stay, similar QOL, and heterogeneous results on respiratory infections. In amyotrophic lateral sclerosis (ALS), DES was associated with higher mortality and similar QOL compared to MV. Most SCI studies had a serious risk of bias.

CONCLUSION

DES shows potential in reducing hospital stay and respiratory infections in SCI but is associated with higher mortality in ALS.

Lung and Diaphragm Protection During Mechanical Ventilation in Patients with Acute Respiratory Distress Syndrome

Patients with acute respiratory distress syndrome often require mechanical ventilation to maintain adequate gas exchange and to reduce the workload of the respiratory muscles. Although lifesaving, positive pressure mechanical ventilation can potentially injure the lungs and diaphragm, further worsening patient outcomes. While the effect of mechanical ventilation on the risk of developing lung injury is widely appreciated, its potentially deleterious effects on the diaphragm have only recently come to be considered by the broader intensive care unit community. Importantly, both ventilator-induced lung injury and ventilator-induced diaphragm dysfunction are associated with worse patient-centered outcomes.

What every paediatrician needs to know about mechanical ventilation

Invasive mechanical ventilation (MV) is one of the most practiced interventions in the intensive care unit (ICU) and is unmistakably lifesaving for children with acute respiratory failure (ARF). However, if delivered inappropriately (i.e. ignoring the respiratory system mechanics and not targeted to the need of the individual patient at a specific time point in the disease trajectory), the side effects will outweigh the benefits. Decades of experimental and clinical investigations have resulted in a better understanding of three important detrimental effects of MV. These are ventilation-induced lung injury (VILI), patient self-inflicted lung injury (P-SILI), and ventilation-induced diaphragmatic injury (VIDD). VILI, P-SILI, and VIDD have in common that they occur when there is either too much or too little ventilatory assistance.Conclusion: The purpose of this review is to give the paediatrician an overview of the challenges to prevent these detrimental effects and titrate MV to the individual patient needs.

Pressure support, patient effort and tidal volume: a conceptual model for a non linear interaction

Pressure support ventilation (PSV) is a form of assisted ventilation which has become frequently used, with the aim of partially unloading the patient's inspiratory muscles. Both under- and over-assistance should be avoided to target a lung- and diaphragm- protective ventilation. Herein, we propose a conceptual model, supported by actual data, to describe how patient and ventilator share the generation of tidal volume (Vt) in PSV and how respiratory system compliance (Crs) affects this interaction. We describe the presence of a patient-specific range of PSV levels, within which the inspiratory effort (Pmus) is modulated, keeping Vt relatively steady on a desired value (Vttarget). This range of assistance may be considered the "adequate PSV assistance" required by the patient, while higher and lower levels may result in over- and under-assistance respectively. As we also show, the determinants of over- and under- assistance borders depend on the combination of Crs and the inspiratory effort which the patient is able to sustain over a period of time. These concepts can be applied at the bedside to understand if the level of assistance is adequate to patient's demand, focusing on the variation of relevant parameters (Vt, Pmus and pressure-muscle-index) as patient reaction to a change in the level of assistance.

A Multidimensional Approach to the Management of Patients in Prolonged Weaning from Mechanical Ventilation: The Concept of Treatable Traits - A Narrative Review

BACKGROUND

Established structured weaning approaches, which are effective for patients in simple and difficult weaning, are often not appropriate for patients undergoing prolonged weaning. Addressing the complexity of weaning failure requires personalized precision medicine. The therapeutic concept of treatable traits (TTs) has been proposed as a new paradigm for the management of chronic respiratory diseases. It is based on a multidimensional assessment of specific characteristics, which can be addressed by specific interventions that go beyond traditional diagnostic criteria. The concept is increasingly adopted for other complex diseases.

SUMMARY

This is a narrative review and an expert opinion on the development of a concept of TTs for patients undergoing prolonged weaning. The proposed TTs are based on a systematic review of risk factors for prolonged weaning, an analysis of claims data to assess risk factors within 96 h of IMV onset and data from the WEAN SAFE study. A multidisciplinary team identified clinically important TTs and determined appropriate interventions. The following TTs have been identified: airway disorders and complications associated with tracheostomy or intubation, such as airway obstruction, strictures or tracheomalacia, infectious aspects, anxiety, depression, delirium, post-traumatic stress disorder, anemia, pulmonary and cardio-renal disease. The multidimensional holistic approach also includes tailored sedation and pain management, nutritional therapy, early mobilization, and physiotherapy.

KEY MESSAGE

We propose a framework of relevant considerations for a multidimensional approach to the management of patients undergoing prolonged weaning that supports the regain of respiratory capacity, reduces the respiratory load, and thus could resolve the respiratory workload imbalance.

Effect of five different body positions on lung function in stroke patients with tracheotomy

BACKGROUND

In stroke patients with tracheotomy, reduced lung function heightens pulmonary infection risk. Body position can affect lung function; however, its impact in stroke patients with tracheostomy remains unclear.

OBJECTIVE

To investigate the influence of five body positions on pulmonary function in stroke patients with tracheotomy.

METHODS

Pulmonary function was assessed in five body positions (supine, supine 30°, supine 60°, sitting, and prone) in 47 stroke patients who underwent tracheotomy. Diaphragmatic excursion during quiet breathing (DEQ), diaphragmatic thickening fraction during quiet breathing (DTFQ), and diaphragmatic excursion during coughing (DEC) were measured using ultrasound. Peak cough flow (PCF) was measured using an electronic peak flow meter.

RESULTS

Different positions had a significant impact on DEQ, DEC, and PCF in stroke patients with tracheotomy, although not on DTFQ. DEQ showed no significant differences between supine 60°, sitting, and prone positions. Both DEC and PCF reached their maximum values in the sitting position. In the sub-group analysis, DEQ in females did not show significant differences across different positions. Both males and females exhibited significantly higher PCF in the sitting compared to supine position. The lung function of obese patients was significantly better in the sitting than in the supine and supine 30° position. Regardless of the patient's level of consciousness and whether the brainstem was injured, lung function in the sitting position was significantly higher than in the supine position.

CONCLUSIONS

Body posture influences lung function in stroke patients with tracheotomy. Patients should adopt a sitting position to enhance pulmonary function.

Phenotypes based on respiratory drive and effort to identify the risk factors when P0.1 fails to estimate ∆PES in ventilated children

BACKGROUND

Monitoring respiratory effort and drive during mechanical ventilation is needed to deliver lung and diaphragm protection. Esophageal pressure (∆PES) is the gold standard measure of respiratory effort but is not routinely available. Airway occlusion pressure in the first 100 ms of the breath (P0.1) is a readily available surrogate for both respiratory effort and drive but is only modestly correlated with ∆PES in children. We sought to identify risk factors for P0.1 over or underestimating ∆PES in ventilated children.

METHODS

Secondary analysis of physiological data from children and young adults enrolled in a randomized controlled trial testing lung and diaphragm protective ventilation in pediatric acute respiratory distress syndrome (PARDS) (NCT03266016). ∆PES (∆PES-REAL), P0.1 and predicted ∆PES (∆PES-PRED = 5.91*P0.1) were measured daily to identify phenotypes based upon the level of respiratory effort and drive: one passive (no spontaneous breathing), three where ∆PES-REAL and ∆PES-PRED were aligned (low, normal, and high effort and drive), two where ∆PES-REAL and ∆PES-PRED were mismatched (high underestimated effort, and overestimated effort). Logistic regression models were used to identify factors associated with each mismatch phenotype (High underestimated effort, or overestimated effort) as compared to all other spontaneous breathing phenotypes.

RESULTS

We analyzed 953 patient days (222 patients). ∆PES-REAL and ∆PES-PRED were aligned in 536 (77%) of the active patient days. High underestimated effort (n = 119 (12%)) was associated with higher airway resistance (adjusted OR 5.62 (95%CI 2.58, 12.26) per log unit increase, p < 0.001), higher tidal volume (adjusted OR 1.53 (95%CI 1.04, 2.24) per cubic unit increase, p = 0.03), higher opioid use (adjusted OR 2.4 (95%CI 1.12, 5.13, p = 0.024), and lower set ventilator rate (adjusted OR 0.96 (95%CI 0.93, 0.99), p = 0.005). Overestimated effort was rare (n = 37 (4%)) and associated with higher alveolar dead space (adjusted OR 1.05 (95%CI 1.01, 1.09), p = 0.007) and lower respiratory resistance (adjusted OR 0.32 (95%CI 0.13, 0.81), p = 0.017).

CONCLUSIONS

In patients with PARDS, P0.1 commonly underestimated high respiratory effort particularly with high airway resistance, high tidal volume, and high doses of opioids. Future studies are needed to investigate the impact of measures of respiratory effort, drive, and the presence of a mismatch phenotype on clinical outcome.

TRIAL REGISTRATION

NCT03266016; August 23, 2017.

Highlights from the Respiratory Failure and Mechanical Ventilation Conference 2024

The Respiratory Intensive Care Assembly of the European Respiratory Society gathered in Berlin to organise the third Respiratory Failure and Mechanical Ventilation Conference in February 2024. The conference covered key points of acute and chronic respiratory failure in adults. During the 3-day conference ventilatory strategies, patient selection, diagnostic approaches, treatment and health-related quality of life topics were addressed by a panel of international experts. In this article, lectures delivered during the event have been summarised by early career members of the Assembly and take-home messages highlighted.

Pressure control plus spontaneous ventilation versus volume assist-control ventilation in acute respiratory distress syndrome. A randomised clinical trial

PURPOSE

The aim of this study was to compare the effect of a pressure-controlled strategy allowing non-synchronised unassisted spontaneous ventilation (PC-SV) to a conventional volume assist-control strategy (ACV) on the outcome of patients with acute respiratory distress syndrome (ARDS).

METHODS

Open-label randomised clinical trial in 22 intensive care units (ICU) in France. Seven hundred adults with moderate or severe ARDS (PaO2/FiO2 < 200 mmHg) were enrolled from February 2013 to October 2018. Patients were randomly assigned to PC-SV (n = 348) or ACV (n = 352) with similar objectives of tidal volume (6 mL/kg predicted body weight) and positive end-expiratory pressure (PEEP). Paralysis was stopped after 24 h and sedation adapted to favour patients' spontaneous ventilation. The primary endpoint was in-hospital death from any cause at day 60.

RESULTS

Hospital mortality [34.6% vs 33.5%, p = 0.77, risk ratio (RR) = 1.03 (95% confidence interval [CI] 0.84-1.27)], 28-day mortality, as well as the number of ventilator-free days and organ failure-free days at day 28 did not differ between PC-SV and ACV groups. Patients in the PC-SV group received significantly less sedation and neuro-muscular blocking agents than in the ACV group. A lower proportion of patients required adjunctive therapy of hypoxemia (including prone positioning) in the PC-SV group than in the ACV group [33.1% vs 41.3%, p = 0.03, RR = 0.80 (95% CI 0.66-0.98)]. The incidences of pneumothorax and refractory hypoxemia did not differ between the groups.

CONCLUSIONS

A strategy based on PC-SV mode that favours spontaneous ventilation reduced the need for sedation and adjunctive therapies of hypoxemia but did not significantly reduce mortality compared to ACV with similar tidal volume and PEEP levels.

Association of diaphragmatic dysfunction with duration of mechanical ventilation in patients in the pediatric intensive care unit: a prospective cohort study

BACKGROUND

Mechanical ventilation (MV) can cause diaphragmatic injury and ventilator induced diaphragmatic dysfunction (VIDD). Diaphragm ultrasonography (DU) is increasingly used to assess diaphragmatic anatomy, function and pathology of patients receiving MV in the pediatric intensive care unit (PICU). We report the poor contractile ability of diaphragm during ventilation of critically ill patients in our PICU and the association to prolonged length of MV and PICU stay.

METHODS

Patients who received MV within 24 h of admission to the PICU, expected to undergo continuous MV for more than 48 h and succeeded to extubate were included in the study. DU monitoring was performed daily after the initiation of MV until extubation. Diaphragm thickening fraction (DTF) measured by DU was used as an indicator of diaphragmatic contractile activity. Patients with bilateral DTF = 0% during DU assessment were allocated into the severe VIDD group (n = 26) and the rest were into non-severe VIDD group (n = 29). The association of severe VIDD with individual length of MV, hospitalization and PICU stay were analyzed.

RESULTS

With daily DU assessment, severe VIDD occurred on 2.9 ± 1.2 days after the initiation of MV, and lasted for 1.9 ± 1.7 days. Values of DTF of all patients recovered to > 10% before extubation. The severe VIDD group had a significantly longer duration (days) of MV [12.0 (8.0-19.3) vs. 5.0 (3.5-7.5), p < 0.001] and PICU stay (days) [30.5 (14.9-44.5) vs. 13.0 (7.0-24.5), p < 0.001]. The occurrence of severe VIDD, first day of severe VIDD and length of severe VIDD were significantly positively associated with the duration of MV and PICU stay. The occurrence of severe VIDD on the second and third days after initiation of MV significantly associated to longer PICU stay (days) [43.0 (9.0-70.0) vs. 13.0 (3.0-40.0), p = 0.009; 36.0 (17.0-208.0) vs. 13.0 (3.0-40.0), p = 0.005, respectively], and the length of MV (days) was significantly longer in those with severe VIDD on the third day after initiation of MV [16.5 (7.0-29.0) vs. 5.0 (2.0-22.0), p = 0.003].

CONCLUSIONS

Daily monitoring of diaphragmatic function with bedside ultrasonography after initiation of MV is necessary in critically ill patients in PICU and the influences and risk factors of severe VIDD need to be further studied. (355 words).

Respiratory Drive, Effort, and Lung-Distending Pressure during Transitioning from Controlled to Spontaneous Assisted Ventilation in Patients with ARDS: A Multicenter Prospective Cohort Study

Objectives: To investigate the impact of patient characteristics and treatment factors on excessive respiratory drive, effort, and lung-distending pressure during transitioning from controlled to spontaneous assisted ventilation in patients with acute respiratory distress syndrome (ARDS). Methods: Multicenter cohort observational study of patients with ARDS at four academic intensive care units. Respiratory drive (P0.1), diaphragm electrical activity (EAdi), inspiratory effort derived from EAdi (∆PmusEAdi) and from occlusion of airway pressure (∆Pocc) (PmusΔPocc), and dynamic transpulmonary driving pressure (ΔPL,dyn) were measured at the first transition to assisted spontaneous breathing. Results: A total of 4171 breaths were analyzed in 48 patients. P0.1 was >3.5 cmH2O in 10%, EAdiPEAK > 15 µV in 29%, ∆PmusEAdi > 15 cmH2O in 28%, and ΔPL,dyn > 15 cmH2O in 60% of the studied breaths. COVID-19 etiology of ARDS was the strongest independent risk factor for a higher proportion of breaths with excessive respiratory drive (RR 3.00 [2.43-3.71], p < 0.0001), inspiratory effort (RR 1.84 [1.58-2.15], p < 0.0001), and transpulmonary driving pressure (RR 1.48 [1.36-1.62], p < 0.0001). The P/F ratio at ICU admission, days of deep sedation, and dose of steroids were additional risk factors for vigorous inspiratory effort. Age and dose of steroids were risk factors for high transpulmonary driving pressure. Days of deep sedation (aHR 1.15 [1.07-1.24], p = 0.0002) and COVID-19 diagnosis (aHR 6.96 [1-48.5], p = 0.05) of ARDS were independently associated with composite outcome of transitioning from light to deep sedation (RASS from 0/-3 to -4/-5) or return to controlled ventilation within 48 h of spontaneous assisted breathing. Conclusions: This study identified that specific patient characteristics, including age, COVID-19-related ARDS, and P/F ratio, along with treatment factors such as the duration of deep sedation and the dosage of steroids, are independently associated with an increased likelihood of assisted breaths reaching potentially harmful thresholds of drive, effort, and lung-distending pressure during the initial transition to spontaneous assisted breathing. It is noteworthy that patients who were subjected to prolonged deep sedation under controlled mechanical ventilation, as well as those with COVID-19, were more susceptible to failing the transition from controlled to assisted breathing.