Coexistence and Impact of Limb Muscle and Diaphragm Weakness at Time of Liberation from Mechanical Ventilation in Medical Intensive Care Unit Patients

Ultrasound-guided Transcutaneous Phrenic Nerve Stimulation in Critically Ill Patients: A New Method to Evaluate Diaphragmatic Function

BACKGROUND

Diaphragm dysfunction is common in intensive care unit and associated with weaning failure and mortality. The diagnosis gold standard is the transdiaphragmatic or tracheal pressure induced by magnetic phrenic nerve stimulation. However, the equipment is not commonly available and requires specific technical skills. This study aimed to evaluate ultrasound-guided transcutaneous phrenic nerve stimulation for daily bedside assessment of diaphragm function by targeted electrical phrenic nerve stimulation.

METHODS

This randomized crossover study compared a new method of ultrasound-guided transcutaneous electrical phrenic nerve stimulation (SONOTEPS) using a peripheral nerve stimulator, with magnetic phrenic nerve stimulation. Intensive care unit adult patients under mechanical ventilation with a Richmond Agitation-Sedation Scale score of -4 or -5 were included. Each patient received the two methods of stimulation, in a randomized order. The primary outcome was the tracheal pressure induced by stimulation.

RESULTS

This study analyzed 232 measures of tracheal pressure from 116 patients, of whom 77 presented diaphragm dysfunction (tracheal pressure less than 11 cm H 2 O) and 50 presented severe diaphragm dysfunction (tracheal pressure less than 8 cm H 2 O). The Passing-Bablok regression showed no significant differences (intercept A of -0.03 [95% CI, -0.83 to 0.52] and slope B of 0.98 [95% CI, 0.90 to 1.05]) between the SONOTEPS method and magnetic stimulation, which were positively correlated ( R ² = 0.639). The mean bias was -1.08 (95% CI, 5.02 to -7.18) cm H 2 O. The receiver operating curves showed an excellent performance for the diagnosis of diaphragm dysfunction and severe diaphragm dysfunction with areas under the curve of 0.90 (95% CI, 0.83 to 0.97) and 0.88 (95% CI, 0.82 to 0.95), respectively. This performance was not significantly affected by the body mass index or the presence of a neck catheter.

CONCLUSIONS

The SONOTEPS method is a simple and accurate tool for bedside assessment of diaphragm function with ultrasound-guided transcutaneous phrenic nerve stimulation in sedated patients with no or minimal spontaneous respiratory activity.

The modified effect of mechanical ventilation setting on relationship between fluid balance and hospital mortality for sepsis patients: a retrospective study

BACKGROUND

Fluid supplement may be affected by ventilatory management due to physiological interaction between heart and lung. The aim of the present study was to explore the effects of ventilator strategies on the relationship of fluid balance and hospital mortality for sepsis patients.

METHODS

This was a retrospective cohort study included sepsis patients with invasive mechanical ventilation (MV) over 24 h from Medical Information Mart for Intensive Care (MIMIC) IV database. The accumulative fluid balance increased by 6 h intervals were calculated as fluid intake minus fluid output. The modes (assisted or controlled) and levels (high or low) of positive end-expiratory pressure (PEEP) of MV every 6 h were recorded. The modification effect for modes and levels of PEEP on the relationship of fluid balance and hospital mortality were tested by multivariable regression models, respectively.

RESULTS

A total of 4466 sepsis patients with invasive MV were included, of which hospital mortality was 26.5%. Fluid balance seemed to have U-shape relationship with hospital mortality. The majority of patients used controlled ventilation at the beginning, and switched to assisted ventilation gradually; however, the PEEP level did not change a lot during the first 24 h. The relationship between fluid balance and hospital mortality was not modified by the ventilator mode; while the PEEP level may modify the relationship.

CONCLUSIONS

For sepsis patients admitted to ICU with invasive MV, the PEEP level, but not the mode of MV, appeared to modify the relationship of fluid balance and hospital mortality. The setting of mechanical ventilation may be an important consideration for fluid therapy.

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.

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.

Intensive care unit acquired weakness and physical rehabilitation in the ICU

Approximately half of critically ill adults experience intensive care unit acquired weakness (ICUAW). Patients who develop ICUAW may have negative outcomes, including longer duration of mechanical ventilation, greater length of stay, and worse mobility, physical functioning, quality of life, and mortality. Early physical rehabilitation interventions have potential for improving ICUAW; however, randomized trials show inconsistent findings on the efficacy of these interventions. This review summarizes the latest evidence on the definition, diagnosis, epidemiology, pathophysiology, risks factors, implications, and management of ICUAW. It specifically highlights research gaps and challenges, with considerations for future research for physical rehabilitation interventions.

Ultrasound-based abdominal muscles and diaphragm assessment in predicting extubation failure in patients requiring neurointensive care: a single-center observational study

Extubation failure rates are notably high in patients in neurointensive care. Ineffective cough is the variable independently associated with extubation failure, but its quantification remains challenging. Patients with primary central nervous system injury requiring invasive mechanical ventilation were included. After a successful spontaneous breathing trial (SBT), abdominal muscles and diaphragm ultrasound were performed under tidal breathing and coughing. 98 patients were initially recruited for the study, and 40 patients were ultimately included in the final analysis. Extubation failure occurred in 8 (20%) patients. Rectus abdominis (RA) and internal oblique (IO) muscles showed difference regarding cough thickening fraction (TF) between the extubation success and failure group (P < 0.05). The logistic regression that analysis suggested cough TFRA, cough TFIO and cough TIO were the factors associated with extubation outcome (P < 0.05). In the receiver operating characteristic analysis, cough TFIO exhibited the strongest predictive value (AUC = 0.957, 95% CI:0.8979-1). A threshold of cough TFIO ≥ 34.15% predicted extubation success with a sensitivity of 93.8% and specificity of 75%. Abdominal muscles ultrasound was a promising tool to predict extubation for patients requiring neurointensive care.Trial registration: The study was registered on Chinese Clinical Trial Registry: ChiCTR2400088210, Registered 13 August 2024 - Retrospectively registered, https://www.chictr.org.cn/bin/project/edit?pid=234150 .

USE OF MUSCULAR ULTRASOUND TO DETECT INTENSIVE CARE UNIT-ACQUIRED WEAKNESS: A SYSTEMATIC REVIEW AND META-ANALYSIS

ABSTRACT

Background : This systematic review and meta-analysis aims to detecting performance of muscular ultrasound for intensive care unit (ICU)-acquired weakness (ICUAW). Methods : We searched PubMed, Web of Science, Embase, Cochrane library, CNKI, VIP, and Wanfang databases for articles published before July 2024. A random-effects model was utilized to derive the summary estimates of sensitivity, specificity, and diagnostic odds ratio (DOR) with 95% confidence interval (CI). Additionally, the sources of heterogeneity were explored by subgroup analysis and meta-regression. Results : This meta-analysis comprised 10 prospective studies involving 561 participants, of whom 241 (42.96%) were diagnosed as ICUAW. Overall, muscular ultrasound exhibited good performance for detecting ICUAW, with the area of summary receiver operating characteristic (SROC) curve of 0.85 (95%CI 0.82-0.88), sensitivity of 0.76 (95%CI 0.70-0.81), specificity of 0.80 (95%CI 0.74-0.84), and DOR of 12.43 (95%CI 7.98-19.38). Upon predefined subgroup analysis, the rectus femoris exhibited significantly superior discriminatory ability in identifying ICUAW than the non-rectus femoris, with higher SROC (0.88 [95%CI 0.85-0.91] vs. 0.76 [95%CI 0.72-0.79], P < 0.01). Moreover, cross-sectional area was more effective than thickness, with higher specificity (0.86 [95%CI 0.80-0.91] vs. 0.74 [95%CI 0.68-0.79], P = 0.02) and SROC (0.89 [95%CI 0.86-0.92] vs. 0.76 [95%CI 0.72-0.80], P < 0.01). Furthermore, integrated analysis of these two indicators revealed that the cross-sectional area of rectus femoris was statistically superior to the thickness of rectus femoris, with higher sensitivity (0.82 [95%CI 0.74-0.87] vs. 0.75 [95%CI 0.65-0.83], P < 0.05) and AUC (0.91 [95%CI 0.88-0.93] vs. 0.80 [95%CI 0.76-0.83], P < 0.01). Conclusions : Muscular ultrasound could be a reliable tool for ICUAW detection. Compared with alternative indices, the cross-sectional area of the rectus femoris exhibits superior detection efficacy and may be considered as a valuable parameter for clinical application.

Effectiveness of physiotherapy modalities on persisting dyspnoea in long COVID: A systematic review and meta-analysis

BACKGROUND

Dyspnoea is often found months and years later in the "long-covid" syndrome, impairing quality of life and further perpetuating anxiety and post-traumatic stress disorders. Physiotherapy was recommended as a treatment in long-covid, but there is still insufficient evidence on its effectiveness.

METHODS

We conducted a systematic literature search on MEDLINE, PEDro, WOS, Scopus, VHL and the Cochrane Library until July 2023 (PROSPERO registration number: CRD42023427464). We selected comparative trials including adults with persistent breathlessness following COVID-19, regardless of the initial severity, for whom physiotherapy was implemented as a treatment for dyspnoea. We followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and assessed the study quality using the PEDro Scale.

RESULTS

19 studies that included 1292 adults fulfilled the inclusion criteria, of which 15 were randomised controlled trials and 4 non-randomised controlled trials. As for the rehabilitation modalities, 6 studies used respiratory muscle training, 6 studies used low to moderate intensity rehabilitation, 6 used high intensity rehabilitation and one used passive rehabilitation. The methods used between and within each group differed greatly, leading to an expected high heterogeneity of results. Nethertheless the random-effects model found a significant difference favouring physiotherapy (SMD -0.63, 95 CI [-1.03; -0.24], p < 0.001, I2 = 88 %). Subgroup analysis showed a significant effect in the high intensity rehabilitation group alone, with null heterogeneity.

CONCLUSION

In people suffering from dyspnoea following a SARS-CoV-2 infection, physiotherapy and especially pulmonary rehabilitation may help alleviate respiratory symptoms. Future studies will need to provide more consistent rehabilitation methods and better descriptions of them so as to reveal clear effects and avoid the confusion caused by using too many rehabilitation modalities.

Establishment of a prediction model for extubation failure risk in ICU patients using bedside ultrasound technology

BACKGROUND

Mechanical ventilation (MV) is crucial for managing critically ill patients; however, extubation failure, associated with adverse outcomes, continues to pose a significant challenge.

OBJECTIVE

The purpose of this prospective observational study was to develop and validate a predictive numerical model utilizing bedside ultrasound to forecast extubation outcomes in ICU patients.

METHODS

We enrolled 300 patients undergoing MV, from whom clinical variables, biomarkers, and ultrasound parameters were collected. Patients were randomly assigned to two groups at a 6:4 ratio: the derivation cohort (n = 180) and the validation cohort (n = 120). A nomogram prediction model was developed using significant predictors identified through multivariate analysis and its performance was assessed and validated by evaluating its discrimination, calibration, and clinical utility.

RESULTS

A total of 300 patients (mean age 72 years; 57.3 % male) were included, with an extubation failure rate of 26.7 %. The model, including diaphragm thickening fraction (OR: 0.890, P = 0.009), modified lung ultrasound score (OR: 1.371, P < 0.001), peak relaxation velocity (OR: 1.515, P = 0.015), and APACHE II (OR: 1.181, P = 0.006), demonstrated substantial discriminative capability, as indicated by an area under the receiver operating characteristic curve (AUC) of 0.886 (95 % CI: 0.830-0.942) for the derivation cohort and 0.846 (95 % CI: 0.827-0.945) for the validation cohort. Hosmer-Lemeshow tests yielded P-values of 0.224 and 0.212 for the derivation and validation cohorts.

CONCLUSIONS

We have established a risk prediction model for extubation failure in mechanically ventilated ICU patients. This risk model base on bedside ultrasound parameters provides valuable insights for identifying high-risk patients and preventing extubation failure.

Contribution and evolution of respiratory muscles function in weaning outcome of ventilator-dependent patients

BACKGROUND

The present study was designed to investigate the evolution and the impact of respiratory muscles function and limb muscles strength on weaning success in prolonged weaning of tracheotomized patients. The primary objective was to determine whether the change in respiratory muscles function and limb muscles strength over the time is or is not associated with weaning success.

METHODS

Tracheotomized patients who were ventilator dependent upon admission at a weaning center were eligible. Diaphragm function was assessed with the phrenic nerve stimulation technique and with ultrasound to measure the diaphragm thickening fraction (TFdi) and diaphragm excursion (EXdi). Global respiratory muscle function was assessed with the maximal inspiratory pressure (MIP) and the forced vital capacity (FVC). Limb muscle strength was measured with the Medical Research Council Score (MRC). Measurements were made on a weekly basis. Patients were compared according to their outcome at discharge: complete weaning, partial weaning or death.

RESULTS

Among the 60 patients who were enrolled, 30 patients finally achieved complete weaning, 20 had partial weaning and 10 died. At 6 months, 6 patients were lost of follow-up, 33 achieved complete weaning, 10 had partial weaning and 11 died. In median, 2 (1-9) assessments were performed per patient. Diaphragm dysfunction was present in all patients with a median Ptr,stim of 5.5 cmH2O (3.0-7.5). Ptr,stim, MIP, TFdi and EXdi at admission were not different between patients who achieved complete weaning and their counterparts. At discharge of the weaning center, MIP, Ptr,stim and EXdi significantly increased in patients who achieved complete weaning. The MRC score significantly increased only in patients with complete weaning. At discharge, diaphragm dysfunction was highly prevalent even in patients with complete weaning (Ptr,stim < 11 cmH2O in n = 11 (37%)).

CONCLUSION

Respiratory muscle function and limb muscles strength are severely impaired in patients with prolonged weaning from mechanical ventilation. Significant improvement of diaphragm ultrasound indices was associated with successful weaning from mechanical ventilation and ICU-acquired weakness upon admission was significantly associated with good outcome suggesting that it was an amendable determinant of weaning failure in this population.

Diaphragmatic ultrasound: approach, emerging evidence, and future perspectives in non-ICU patients

Diaphragmatic dysfunction is an important contributor to hypercapnic respiratory failure, but its presence is often challenging to determine at the bedside. Diaphragm ultrasound provides an opportunity to evaluate the function of the diaphragm noninvasively by evaluating the following parameters that can help define diaphragmatic dysfunction: diaphragm excursion, diaphragm muscle thickness, and thickening fraction. Its evaluation has the potential to assist with diagnosis of respiratory failure, provide prognosis, and assist with patient monitoring and should be considered as part of an internal medicine physician's and emergency physician's skill set. This article provides an overview on how to perform diaphragm ultrasound, review its pitfalls, and discuss the evidence of its use in patients with neuromuscular disorders and chronic obstructive pulmonary disease. Finally, its potential emerging uses in the perioperative setting and for evaluation of acute heart failure are discussed.

Speckle tracking ultrasound as a new tool to predict the weaning outcome of mechanical ventilation patients: a prospective observational study

Introduction

Speckle tracking ultrasound is a novel technique for evaluating diaphragm movement, yet its guidance in weaning mechanically ventilated patients remains unclear. In this study, we assessed diaphragmatic function using speckle tracking ultrasound and guided the weaning process.

Methods

A total of 86 mechanically ventilated patients were included and divided into successful or failed weaning groups. Diaphragmatic function was assessed using speckle tracking ultrasound, M-ultrasound diaphragm excursion (DE), and diaphragmatic twitch force (DTF) after 30 min spontaneous breathing trial (SBT). The diagnostic performance of these indicator in predicting weaning outcomes was also evaluated.

Results

In this study, a total of 86 patients completed the follow-up for weaning outcomes, with 35 cases of weaning failure and 51 cases of successful weaning. Logistic regression analysis identified whole strain (p = 0.037) and DE (p = 0.004) as independent predictors of weaning outcome. Receiver operating characteristic (ROC) curve showed that the strain threshold for Costal Diaphragm (Dlcos) was -9.836, Area Under the Curve (AUC) value was 0.760, the predictive specificity for weaning failure was 72.5%, and the sensitivity was 80%. DE value exceeding 1.015 cm had an AUC value of 0.785, noting that DE value had a high specificity (90.2%) for predicting successful weaning, but a lower sensitivity (60%). After merging, the AUC of whole strain and DE was 0.856, and the sensitivity (80%) and specificity (80.4%) were more balanced compared to using DE alone.

Conclusion

The findings of this study demonstrate the feasibility of using speckle tracking ultrasound to assess diaphragmatic function in mechanically ventilated patients. The combined utilization of whole strain and DE provides a more precise evaluation of diaphragmatic function in ICU patient, which may improve patient outcome.

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.

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.

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.

Inspiratory muscle training for mechanically ventilated patients in the intensive care unit: Obstacles and facilitators for implementation. A mixed method quality improvement study

BACKGROUND

Mechanically ventilated patients are at risk of developing inspiratory muscle weakness (IMW), which is associated with failure to wean and poor outcomes. Inspiratory muscle training (IMT) is a recommended intervention during and after extubation but has not been widely adopted in Dutch intensive care units (ICUs).

OBJECTIVES

The objective of this study was to explore the potential, barriers, and facilitators for implementing IMT as treatment modality for mechanically ventilated patients.

METHODS

This mixed-method, proof-of-concept study was conducted in a large academic hospital in the Netherlands. An evidence-based protocol for assessing IMW and training was applied to patients ventilated for ≥24 h in the ICU during an 8-month period in 2021. Quantitative data on completed measurements and interventions during and after ICU-stay were collected retrospectively and were analysed descriptively. Qualitative data were collected through semistructured interviews with physiotherapists executing the new protocol. Interview data were transcribed and thematically analysed.

FINDINGS

Of the 301 screened patients, 11.6% (n = 35) met the inclusion criteria. Measurements were possible in 94.3% of the participants, and IMW was found in 78.8% of the participants. Ninety-six percent started training in the ICU, and 88.5% continued training after transfer to the ward. Follow-up measurements were achieved in 73.1% of the patients with respiratory muscle weakness. Twelve therapists were interviewed, of whom 41.7% regularly worked in the ICU. When exploring reasons for protocol deviation, three themes emerged: "professional barriers", "external factors", and "patient barriers".

CONCLUSIONS

Implementation of measurements of and interventions for IMW showed to be challenging in this single centre study. Clinicians' willingness to change their handling was related to beliefs regarding usefulness, effectiveness, and availability of time and material. We recommend that hospitals aiming to implement IMT during or after ventilator weaning consider these professional and organisational barriers for implementation of novel, evidence-based interventions into daily clinical practice.

Impact of COVID-19 on Diaphragmatic Function: Understanding Multiorgan Involvement and Long-Term Consequences

The COVID-19 pandemic has brought significant attention to the respiratory system, with much focus on lung-related disorders. However, the diaphragm, a crucial component of respiratory physiology, has not been adequately studied, especially in the context of long COVID. This review explores the multipotential role of the diaphragm in both respiratory health and disease, emphasizing its involvement in long-term complications following SARS-CoV-2 infection. The diaphragm's fundamental role in respiratory physiology and its impact on balance and posture control, breathing patterns, and autonomic nervous system regulation are discussed. This review examines complications arising from COVID-19, highlighting the diaphragm's involvement in neurological, musculoskeletal, and inflammatory responses. Particular attention is given to the neuroinvasive impact of SARS-CoV-2, the inflammatory response, and the direct viral effects on the diaphragm. The diaphragm's role in long COVID is explored, with a focus on specific symptoms such as voice disorders, pelvic floor dysfunction, and sleep disturbances. Diagnostic challenges, current methods for assessing diaphragmatic dysfunction, and the complexities of differentiating it from other conditions are also explored. This article is the first to comprehensively address diaphragmatic dysfunction resulting from COVID-19 and long COVID across various physiological and pathological aspects, offering a new perspective on its diagnosis and treatment within a multisystem context.

Effectiveness of abdominal sandbag training in enhancing diaphragm muscle function and exercise tolerance in patients with chronic respiratory failure

BACKGROUND

Chronic respiratory failure is a common cause of ventilator dependence in the intensive care unit (ICU). The causes of chronic respiratory failure include primary disease or complications, such as ICU-acquired weakness. Traditional practice requires patients to remain immobile and bedridden; however, recent evidence suggests that early adequate exercise promotes recovery without increasing risks. In this study, we explored the efficacy of planned progressive abdominal sandbag training in promoting the successful withdrawal of patients with chronic respiratory failure from mechanical ventilation.

METHODS

This study was conducted between April 2019 and November 2020. Patients were recruited and divided into two groups: abdominal sandbag training group and control group (no training). The training group participated in a 3-month daily pulmonary rehabilitation program, which involved a 30-min session of progressive sandbag loading on the upper abdomen as a form of diaphragmatic resistant exercise. The pressure support level of the ventilator was adjusted to maintain a tidal volume of 8 mL/kg. To investigate the effect of abdominal sandbag training on patients with chronic respiratory failure, we compared tidal volume, shallow breathing index, maximum respiratory pressure, and diaphragm characteristics between the training and control groups.

RESULTS

This study included 31 patients; of them, 17 (54.8 %) received abdominal sandbag training and 14 (45.2 %) did not. No significant between-group difference was found in baseline characteristics. Compared with the control group, the training group exhibited considerable improvements in ventilation-related parameters (p < 0.001): the tidal volume markedly increased (p = 0.012), rapid shallow breathing index declined (p = 0.016), and maximum respiratory pressure increased (p < 0.001) in the training group. The diaphragm motion value (p = 0.048) and diaphragm thickness (p = 0.041) were greater in the training group than in the control group. Nine patients (52.9 %) in the training group were removed from the ventilator compared with 1 (7.1 %) in the control group (p = 0.008).

CONCLUSION

Abdominal sandbag training may be beneficial for patients dependent on a ventilator. The training improves the function of the diaphragm muscle, thereby increasing tidal volume and reducing the respiratory rate and rapid shallow breathing index, thus facilitating withdrawal from ventilation. This training approach may also improve the thickness and motion of the diaphragm and the rate of ventilator detachment.

Respiratory muscle dysfunction in acute and chronic respiratory failure: how to diagnose and how to treat?

Assessing and treating respiratory muscle dysfunction is crucial for patients with both acute and chronic respiratory failure. Respiratory muscle dysfunction can contribute to the onset of respiratory failure and may also worsen due to interventions aimed at treatment. Evaluating respiratory muscle function is particularly valuable for diagnosing, phenotyping and assessing treatment efficacy in these patients. This review outlines established methods, such as measuring respiratory pressures, and explores novel techniques, including respiratory muscle neurophysiology assessments using electromyography and imaging with ultrasound.Additionally, we review various treatment strategies designed to support and alleviate the burden on overworked respiratory muscles or to enhance their capacity through training interventions. These strategies range from invasive and noninvasive mechanical ventilation approaches to specialised respiratory muscle training programmes. By summarising both established techniques and recent methodological advancements, this review aims to provide a comprehensive overview of the tools available in clinical practice for evaluating and treating respiratory muscle dysfunction. Our goal is to present a clear understanding of the current capabilities and limitations of these diagnostic and therapeutic approaches. Integrating advanced diagnostic methods and innovative treatment strategies should help improve patient management and outcomes. This comprehensive review serves as a resource for clinicians, equipping them with the necessary knowledge to effectively diagnose and treat respiratory muscle dysfunction in both acute and chronic respiratory failure scenarios.

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).

ICU patients receiving remifentanil do not experience reduced duration of mechanical ventilation: a systematic review of randomized controlled trials and network meta-analyses based on Bayesian theories

Background

The purpose of this network meta-analysis (NMA) was to evaluate the efficacy of intravenous opioid μ-receptor analgesics in shortening the duration of mechanical ventilation (MV) in ICU patients.

Methods

Randomized controlled trials comparing the efficacy of remifentanil, sufentanil, morphine, and fentanyl on the duration of MV in ICU patients were searched in Embase, Cochrane, Pubmed, and Web of Science electronic databases. The primary outcome was MV duration. The Bayesian random-effects framework was used to evaluate relative efficacy.

Results

In total 20 studies were included in this NMA involving 3,442 patients. Remifentanil was not associated with a reduction in the duration of MV compared with fentanyl (mean difference (MD) -0.16; 95% credible interval (CrI): -4.75 ~ 5.63) and morphine (MD 3.84; 95% CrI: -0.29 ~ 10.68). The secondary outcomes showed that, compared with remifentanil, sufentanil can prolong the duration of extubation. No regimen significantly shortened the ICU length of stay and improved the ICU mortality, efficacy, safety, and drug-related adverse events.

Conclusion

Among these analgesics, remifentanil did not appear to be associated with a reduction in MV duration. Clinicians should carefully titrate the analgesia of MV patients to prevent a potentially prolonged duration of MV due to excessive or inadequate analgesic therapy.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, CRD42021232604.

The ReInvigorate Study-phrenic nerve-to-diaphragm stimulation for weaning from mechanical ventilation: a protocol for a randomized pivotal clinical trial

BACKGROUND

In the United States in 2017, there were an estimated 903,745 hospitalizations involving mechanical ventilation (MV). Complications from ventilation can result in longer hospital stays, increased risk of disability, and increased healthcare costs. It has been hypothesized that electrically pacing the diaphragm by phrenic nerve stimulation during mechanical ventilation may minimize or reverse diaphragm dysfunction, resulting in faster weaning.

METHODS

The ReInvigorate Trial is a prospective, multicenter, randomized, controlled clinical trial evaluating the safety and efficacy of Stimdia's pdSTIM System for facilitating weaning from MV. The pdSTIM system employs percutaneously placed multipolar electrodes to stimulate the cervical phrenic nerves and activate contraction of the diaphragm bilaterally. Patients who were on mechanical ventilation for at least 96 h and who failed at least one weaning attempt were considered for enrollment in the study. The primary efficacy endpoint was the time to successful liberation from mechanical ventilation (treatment vs. control). Secondary endpoints will include the rapid shallow breathing index and other physiological and system characteristics. Safety will be summarized for both primary and additional analyses. All endpoints will be evaluated at 30 days or at the time of removal of mechanical ventilation, whichever is first.

DISCUSSION

This pivotal study is being conducted under an investigational device exception with the U.S. Food and Drug Administration. The technology being studied could provide a first-of-kind therapy for difficult-to-wean patients on mechanical ventilation in an intensive care unit setting.

TRIAL REGISTRATION

Clinicaltrials.gov, NCT05998018 , registered August 2023.

Feasibility of veno-arterial extracorporeal life support in awake patients with cardiogenic shock

OBJECTIVES

This study sought to demonstrate outcomes of veno-arterial extracorporeal life support (VA-ECLS) in non-intubated ('awake') patients with cardiogenic shock, as very few studies have investigated safety and feasibility in this population.

METHODS

This was a retrospective review of 394 consecutive VA-ECLS patients at our institution from 2017 to 2021. We excluded patients cannulated for indications definitively associated with intubation. Patients were stratified by intubation status at time of cannulation and baseline differences were balanced by inverse probability of treatment weighting. The primary outcome was in-hospital mortality while secondary outcomes included adverse events during ECLS and destination at discharge.

RESULTS

Out of 135 patients in the final cohort, 79 were intubated and 56 were awake at time of cannulation. All awake patients underwent percutaneous femoral cannulation with technical success of 100% without intubation. Indications for VA-ECLS in awake patients included acute decompensated heart failure (64.3%), pulmonary hypertension or massive pulmonary embolism (12.5%), myocarditis (8.9%) and acute myocardial infarction (5.4%). After adjustment, awake and intubated patients had similar ECLS duration (7 vs 6 days, P = 0.19), in-hospital mortality (39.6% vs 51.7%, P = 0.28), and rates of various adverse events. Intubation status was not a significant risk factor for 90-day mortality (hazard ratio [95% confidence interval]: 1.26 [0.64, 2.45], P = 0.51) in multivariable analysis. Heart transplantation (15.1% vs 4.9%) and ventricular assist device (17.4% vs 2.2%) were more common destinations at discharge in awake patients than intubated patients (P = 0.02).

CONCLUSIONS

Awake VA-ECLS is safe and feasible with comparable outcomes as intubated counterparts in select cardiogenic shock patients.

Development of a machine learning model for prediction of the duration of unassisted spontaneous breathing in patients during prolonged weaning from mechanical ventilation

PURPOSE

Treatment of patients undergoing prolonged weaning from mechanical ventilation includes repeated spontaneous breathing trials (SBTs) without respiratory support, whose duration must be balanced critically to prevent over- and underload of respiratory musculature. This study aimed to develop a machine learning model to predict the duration of unassisted spontaneous breathing.

MATERIALS AND METHODS

Structured clinical data of patients from a specialized weaning unit were used to develop (1) a classifier model to qualitatively predict an increase of duration, (2) a regressor model to quantitatively predict the precise duration of SBTs on the next day, and (3) the duration difference between the current and following day. 61 features, known to influence weaning, were included into a Histogram-based gradient boosting model. The models were trained and evaluated using separated data sets.

RESULTS

18.948 patient-days from 1018 individual patients were included. The classifier model yielded an ROC-AUC of 0.713. The regressor models displayed a mean absolute error of 2:50 h for prediction of absolute durations and 2:47 h for day-to-day difference.

CONCLUSIONS

The developed machine learning model showed informed results when predicting the spontaneous breathing capacity of a patient in prolonged weaning, however lacking prognostic quality required for direct translation to clinical use.

Super-relaxed myosins contribute to respiratory muscle hibernation in mechanically ventilated patients

Patients receiving mechanical ventilation in the intensive care unit (ICU) frequently develop contractile weakness of the diaphragm. Consequently, they may experience difficulty weaning from mechanical ventilation, which increases mortality and poses a high economic burden. Because of a lack of knowledge regarding the molecular changes in the diaphragm, no treatment is currently available to improve diaphragm contractility. We compared diaphragm biopsies from ventilated ICU patients (N = 54) to those of non-ICU patients undergoing thoracic surgery (N = 27). By integrating data from myofiber force measurements, x-ray diffraction experiments, and biochemical assays with clinical data, we found that in myofibers isolated from the diaphragm of ventilated ICU patients, myosin is trapped in an energy-sparing, super-relaxed state, which impairs the binding of myosin to actin during diaphragm contraction. Studies on quadriceps biopsies of ICU patients and on the diaphragm of previously healthy mechanically ventilated rats suggested that the super-relaxed myosins are specific to the diaphragm and not a result of critical illness. Exposing slow- and fast-twitch myofibers isolated from the diaphragm biopsies to small-molecule compounds activating troponin restored contractile force in vitro. These findings support the continued development of drugs that target sarcomere proteins to increase the calcium sensitivity of myofibers for the treatment of ICU-acquired diaphragm weakness.

Impacts of three inspiratory muscle training programs on inspiratory muscles strength and endurance among intubated and mechanically ventilated patients with difficult weaning: a multicentre randomised controlled trial

BACKGROUND

Inspiratory muscle training (IMT) is well-established as a safe option for combating inspiratory muscles weakness in the intensive care setting. It could improve inspiratory muscle strength and decrease weaning duration but a lack of knowledge on the optimal training regimen raise to inconsistent results. We made the hypothesis that an innovative mixed intensity program for both endurance and strength improvement could be more effective. We conducted a multicentre randomised controlled parallel trial comparing the impacts of three IMT protocols (low, high, and mixed intensity) on inspiratory muscle strength and endurance among difficult-to-wean patients.

METHODS

Ninety-two patients were randomly assigned to three groups with different training programs, where each performed an IMT program twice daily, 7 days per week, from inclusion until successful extubation or 30 days. The primary outcome was maximal inspiratory pressure (MIP) increase. Secondary outcomes included peak pressure (Ppk) increase as an endurance marker, mechanical ventilation (MV) duration, ICU length of stay, weaning success defined by a 2-day ventilator-free after extubation, reintubation rate and safety.

RESULTS

MIP increases were 10.8 ± 11.9 cmH2O, 4.5 ± 14.8 cmH2O, and 6.7 ± 14.5 cmH2O for the mixed intensity (MI), low intensity (LI), and high intensity (HI) groups, respectively. There was a non-statistically difference between the MI and LI groups (mean adjusted difference: 6.59, 97.5% CI [- 14.36; 1.18], p = 0.056); there was no difference between the MI and HI groups (mean adjusted difference: - 3.52, 97.5% CI [- 11.57; 4.53], p = 0.321). No significant differences in Ppk increase were observed among the three groups. Weaning success rate observed in MI, HI and LI group were 83.7% [95% CI 69.3; 93.2], 82.6% [95% CI 61.2; 95.0] and 73.9% [95% CI 51.6; 89.8], respectively. MV duration, ICU length of stay and reintubation rate had similar values. Over 629 IMT sessions, six adverse events including four spontaneously reversible bradycardia in LI group were possibly related to the study.

CONCLUSIONS

Among difficult-to-wean patients receiving invasive MV, no statistically difference was observed in strength and endurance progression across three different IMT programs. IMT appears to be feasible in usual cares, but some serious adverse events such as bradycardia could motivate further research on the specific impact on cardiac system. Trial registration Clinicaltrials.gov identifier: NCT02855619. Registered 28 September 2014.

Operator independent continuous ultrasound monitoring of diaphragm excursion predicts successful weaning from mechanical ventilation: a prospective observational study

BACKGROUND

In mechanically ventilated patients, diaphragm ultrasound can identify diaphragm weakness and predict weaning failure. We evaluated whether a novel operator-independent ultrasound-based medical device allowing continuous monitoring of the diaphragm (CUSdi) could reliably (1) measure diaphragm excursion (EXdi) and peak contraction velocity (PCVdi), (2) predict weaning outcome, and (3) approximate transdiaphragmatic pressure (Pdi).

METHODS

In 49 mechanically ventilated patients, CUSdi was recorded during a 30-min spontaneous breathing trial (SBT), and EXdi and PCVdi were measured. In subgroups of patients, standard ultrasound measurement of EXdi and PCVdi was performed (n = 36), and Pdi derived parameters (peak and pressure time product, n = 30) were measured simultaneously.

RESULTS

The agreement bias between standard ultrasound and CUSdi for EXdi was 0.1 cm (95% confidence interval -0.7-0.9 cm). The regression of Passing-Bablok indicated a lack of systematic difference between EXdi measured with standard ultrasound and CUSdi, which were positively correlated (Rho = 0.84, p < 0.001). Weaning failure was observed in 54% of patients. One, two and three minutes after the onset of the SBT, EXdi was higher in the weaning success group than in the failure group. Two minutes after the onset of the SBT, an EXdi < 1.1 cm predicted weaning failure with a sensitivity of 0.83, a specificity of 0.68, a positive predictive value of 0.76, and a negative predictive value of 0.24. There was a weak correlation between EXdi and both peak Pdi (r = 0.22, 95% confidence interval 0.15 - 0.28) and pressure time product (r = 0.13, 95% confidence interval 0.06 - 0.20). Similar results were observed with PCVdi.

CONCLUSIONS

Operator-independent continuous diaphragm monitoring quantifies EXdi reliably and can predict weaning failure with an identified cut-off value of 1.1 cm. Trial registration clinicaltrial.gov, NCT04008875 (submitted 12 April 2019, posted 5 July 2019) and NCT03896048 (submitted 27 March 2019, posted 29 March 2019).

High Airway Occlusion Pressure Is Associated with Dyspnea and Increased Mortality in Critically Ill Mechanically Ventilated Patients

Rationale: Airway occlusion pressure at 100 ms (P0.1) reflects central respiratory drive. Objectives: We aimed to assess factors associated with P0.1 and whether an abnormally low or high P0.1 value is associated with higher mortality and longer duration of mechanical ventilation (MV). Methods: We performed a secondary analysis of a prospective cohort study conducted in 10 ICUs in France to evaluate dyspnea in communicative MV patients. In patients intubated for more than 24 hours, P0.1 was measured with dyspnea as soon as patients could communicate and the next day. Measurements and Main Results: Among 260 patients assessed after a median time of ventilation of 4 days, P0.1 was 1.9 (1-3.5) cm H2O at enrollment, 24% had P0.1 values >3.5 cm H2O, 37% had P0.1 values between 1.5 and 3.5 cm H2O, and 39% had P0.1 values <1.5 cm H2O. In multivariable linear regression, independent factors associated with P0.1 were the presence of dyspnea (P = 0.037), respiratory rate (P < 0.001), and PaO2 (P = 0.008). Ninety-day mortality was 33% in patients with P0.1 > 3.5 cm H2O versus 19% in those with P0.1 between 1.5 and 3.5 cm H2O and 17% in those with P0.1 < 1.5 cm H2O (P = 0.046). After adjustment for the main risk factors, P0.1 was associated with 90-day mortality (hazard ratio per 1 cm H2O, 1.19 [95% confidence interval, 1.04-1.37]; P = 0.011). P0.1 was also independently associated with a longer duration of MV (hazard ratio per 1 cm H2O, 1.10 [95% confidence interval, 1.02-1.19]; P = 0.016). Conclusions: In patients receiving invasive MV, abnormally high P0.1 values may suggest dyspnea and are associated with higher mortality and prolonged duration of MV.

Ultrasonographic Assessment of the Diaphragm

Mechanical ventilation injures not only the lungs but also the diaphragm, resulting in dysfunction associated with poor outcomes. Diaphragm ultrasonography is a noninvasive, cost-effective, and reproducible diagnostic method used to monitor the condition and function of the diaphragm. With advances in ultrasound technology and the expansion of its clinical applications, diaphragm ultrasonography has become increasingly important as a tool to visualize and quantify diaphragmatic morphology and function across multiple medical specialties, including pulmonology, critical care, and rehabilitation medicine. This comprehensive review aims to provide an in-depth analysis of the role and limitations of ultrasonography in assessing the diaphragm, especially among critically ill patients. Furthermore, we discuss a recently published expert consensus and provide a perspective for the future.

EFFECTS OF LEVOSIMENDAN ON DIAPHRAGMATIC DYSFUNCTION IN PATIENTS WITH SEPSIS

ABSTRACT

Objective: In this study, our aim was to examine the effects of levosimendan on diaphragmatic dysfunction in patients with sepsis, as well as assess its impact on respiratory muscle contractility and the outcome of weaning. Methods: This was a single-blind, randomized, controlled trial. Patients with diaphragmatic dysfunction and failure of spontaneous breathing trials (SBTs) were randomly and equally assigned to the experimental and control groups. The experimental group received levosimendan at a loading dose of 6 μg/kg for 10 min, followed by a continuous infusion at 0.2 μg/kg/min. The control group received an equivalent dose of a placebo. The preadministration and postadministration respiratory mechanics parameters of the patients were recorded. Evaluation of the effect of levosimendan on patients with sepsis-induced diaphragm dysfunction comprised arterial blood gas analysis as well as ultrasound measurements of diaphragm excursion (DE), diaphragm thickness (DT), diaphragm thickening fraction (TFdi), and diaphragm-rapid shallow breathing index (D-RSBI). Results: Forty-four patients were enrolled in the study. We found that postadministration of levosimendan, the patients' tidal volume (GCSMV) increased, whereas the D-RSBI decreased, and the partial pressure of carbon dioxide (PACO 2 ) decreased when compared to the preadministration levels. Additionally, following levosimendan administration, patients showed increased DE and pressure support (PS) when compared to before administration (1.14 ± 0.177 vs. 1.22 ± 0.170 cm and 0.248 ± 0.03 vs. 0.284 ± 0.06, respectively) and decreased D-RSBI (22.76 ± 6.14 vs. 20.06 ± 6.04, respectively), all of which were statistically significant ( P < 0.05). In contrast, in the control group of patients, there were no statistically significant differences in the postadministration levels of DE, TFdi, and D-RSBI as compared to the preadministration period ( P > 0.05). Furthermore, in terms of weaning outcomes, we did not find any statistically significant difference in the number of patients in the two groups who eventually underwent weaning ( P = 0.545). Conclusion: In this study, we found that levosimendan enhanced diaphragm contractile function. However, further investigations are required to explore its effect on weaning outcomes in patients undergoing mechanical ventilation.

Ultrasound assessment of diaphragmatic dysfunction in non-critically ill patients: relevant indicators and update

Diaphragm dysfunction (DD) can be classified as mild, resulting in diaphragmatic weakness, or severe, resulting in diaphragmatic paralysis. Various factors such as prolonged mechanical ventilation, surgical trauma, and inflammation can cause diaphragmatic injury, leading to negative outcomes for patients, including extended bed rest and increased risk of pulmonary complications. Therefore, it is crucial to protect and monitor diaphragmatic function. Impaired diaphragmatic function directly impacts ventilation, as the diaphragm is the primary muscle involved in inhalation. Even unilateral DD can cause ventilation abnormalities, which in turn lead to impaired gas exchange, this makes weaning from mechanical ventilation challenging and contributes to a higher incidence of ventilator-induced diaphragm dysfunction and prolonged ICU stays. However, there is insufficient research on DD in non-ICU patients, and DD can occur in all phases of the perioperative period. Furthermore, the current literature lacks standardized ultrasound indicators and diagnostic criteria for assessing diaphragmatic dysfunction. As a result, the full potential of diaphragmatic ultrasound parameters in quickly and accurately assessing diaphragmatic function and guiding diagnostic and therapeutic decisions has not been realized.

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.

Risk factors and clinical prediction models for prolonged mechanical ventilation after heart valve surgery

OBJECTIVES

Prolonged mechanical ventilation (PMV) is a common complication following cardiac surgery linked to unfavorable patient prognosis and increased mortality. This study aimed to search for the factors associated with the occurrence of PMV after valve surgery and to develop a risk prediction model.

METHODS

The patient cohort was divided into two groups based on the presence or absence of PMV post-surgery. Comprehensive preoperative and intraoperative clinical data were collected. Univariate and multivariate logistic regression analyses were employed to identify risk factors contributing to the incidence of PMV. Based on the logistic regression results, a clinical nomogram was developed.

RESULTS

The study included 550 patients who underwent valve surgery, among whom 62 (11.27%) developed PMV. Multivariate logistic regression analysis revealed that age (odds ratio [OR] = 1.082, 95% confidence interval [CI] = 1.042-1.125; P < 0.000), current smokers (OR = 1.953, 95% CI = 1.007-3.787; P = 0.047), left atrial internal diameter index (OR = 1.04, 95% CI = 1.002-1.081; P = 0.041), red blood cell count (OR = 0.49, 95% CI = 0.275-0.876; P = 0.016), and aortic clamping time (OR = 1.031, 95% CI = 1.005-1.057; P < 0.017) independently influenced the occurrence of PMV. A nomogram was constructed based on these factors. In addition, a receiver operating characteristic (ROC) curve was plotted, with an area under the curve (AUC) of 0.782 and an accuracy of 0.884.

CONCLUSION

Age, current smokers, left atrial diameter index, red blood cell count, and aortic clamping time are independent risk factors for PMV in patients undergoing valve surgery. Furthermore, the nomogram based on these factors demonstrates the potential for predicting the risk of PMV in patients following valve surgery.

Feasibility, safety, and patient acceptability of electronic inspiratory muscle training in patients who require prolonged mechanical ventilation in the intensive care unit: A dual-centre observational study

BACKGROUND

Inspiratory muscle training (IMT) is an intervention that can be used to rehabilitate the respiratory muscle deconditioning experienced by patients with critical illness, requiring prolonged mechanical ventilation. Clinicians are currently using mechanical threshold IMT devices that have limited resistance ranges.

OBJECTIVES

The objective of this study was to evaluate the safety, feasibility, and acceptability of using an electronic device to facilitate IMT with participants requiring prolonged mechanical ventilation.

METHOD

A dual-centre observational cohort study, with convenience sampling, was conducted at two tertiary intensive care units. Daily training supervised by intensive care unit physiotherapists was completed with the electronic IMT device. A priori definitions for feasibility, safety, and acceptability were determined. Feasibility was defined as more than 80% of planned sessions completed. Safety was defined as no major adverse events and less than 3% minor adverse event rate, and acceptability was evaluated following the acceptability of intervention framework principles.

RESULTS

Forty participants completed 197 electronic IMT treatment sessions. Electronic IMT was feasible, with 81% of planned sessions completed. There were 10% minor adverse events and no major adverse events. All the minor adverse events were transient without clinical consequences. All the participants who recalled completing electronic IMT sessions reported that the training was acceptable. Acceptability was demonstrated; over 85% of participants reported that electronic IMT was either helpful or beneficial and that electronic IMT assisted their recovery.

CONCLUSION

Electronic IMT is feasible and acceptable to complete with critically ill participants who require prolonged mechanical ventilation. As all minor adverse events were transient without clinical consequences, electronic IMT can be considered a relatively safe intervention with patients who require prolonged mechanical ventilation.

Physical and Cognitive Impairment in Acute Respiratory Failure

Recent research has brought renewed attention to the multifaceted physical and cognitive dysfunction that accompanies acute respiratory failure (ARF). This state-of-the-art review provides an overview of the evidence landscape encompassing ARF-associated neuromuscular and neurocognitive impairments. Risk factors, mechanisms, assessment tools, rehabilitation strategies, approaches to ventilator liberation, and interventions to minimize post-intensive care syndrome are emphasized. The complex interrelationship between physical disability, cognitive dysfunction, and long-term patient-centered outcomes is explored. This review highlights the need for comprehensive, multidisciplinary approaches to mitigate morbidity and accelerate recovery.

Critical illness-associated limb and diaphragmatic weakness

PURPOSE OF REVIEW

In the current review, we aim to highlight the evolving evidence on the diagnosis, prevention and treatment of critical illness weakness (CIW) and critical illness associated diaphragmatic weakness (CIDW).

RECENT FINDINGS

In the ICU, several risk factors can lead to CIW and CIDW. Recent evidence suggests that they have different pathophysiological mechanisms and impact on outcomes, although they share common risk factors and may overlap in several patients. Their diagnosis is challenging, because CIW diagnosis is primarily clinical and, therefore, difficult to obtain in the ICU population, and CIDW diagnosis is complex and not easily performed at the bedside. All of these issues lead to underdiagnosis of CIW and CIDW, which significantly increases the risk of complications and the impact on both short and long term outcomes. Moreover, recent studies have explored promising diagnostic techniques that are may be easily implemented in daily clinical practice. In addition, this review summarizes the latest research aimed at improving how to prevent and treat CIW and CIDW.

SUMMARY

This review aims to clarify some uncertain aspects and provide helpful information on developing monitoring techniques and therapeutic interventions for managing CIW and CIDW.

The effect of high-flow oxygen via tracheostomy on respiratory pattern and diaphragmatic function in patients with prolonged mechanical ventilation: A randomized, physiological, crossover study

Background

Compared to conventional oxygen devices, high-flow oxygen treatment (HFOT) through the nasal cannulae has demonstrated clinical benefits. Limited data exist on whether such effects are also present in HFOT through tracheostomy. Hence, we aimed to examine the short-term effects of HFOT through tracheostomy on diaphragmatic function and respiratory parameters in tracheostomized patients on prolonged mechanical ventilation.

Methods

A randomized, crossover, physiological study was conducted in our ICU between December 2020 and April 2021, in patients with tracheostomy and prolonged mechanical ventilation. The patients underwent a 30-min spontaneous breathing trial (SBT) and received oxygen either via T-piece or by HFOT through tracheostomy, followed by a washout period of 15-min breathing through the T-piece and receipt of 30-min oxygen with the other modality in a randomized crossover manner. At the start and end of each session, blood gasses, breathing frequency (f), and tidal volume (VT) via a Wright's spirometer were measured, along with diaphragm ultrasonography including diaphragm excursion and diaphragmatic thickening fraction, which expressed the inspiratory muscle effort.

Results

Eleven patients were enrolled in whom 19 sessions were uneventfully completed; eight patients were studied twice on two different days with alternate sessions; and three patients were studied once. Patients were randomly assigned to start the SBT with a T-piece (n=10 sessions) or with HFOT (n=9 sessions). With HFOT, VT and minute ventilation (VE) significantly increased during SBT (from [465±119] mL to [549±134] mL, P <0.001 and from [12.4±4.3] L/min to [13.1±4.2] L/min, P <0.05, respectively), but they did not change significantly during SBT with T-piece (from [495±132] mL to [461±123] mL and from [12.8±4.4] mL to [12.0±4.4] mL, respectively); f/VT decreased during HFOT (from [64±31] breaths/(min∙L) to [49±24] breaths/(min∙L), P <0.001), but it did not change significantly during SBT with T-piece (from [59±28] breaths/(min∙L) to [64±33] breaths/(min∙L)); partial pressure of arterial oxygen increased during HFOT (from [99±39] mmHg to [132±48] mmHg, P <0.001), but it decreased during SBT with T-piece (from [124±50] mmHg to [83±22] mmHg, P <0.01). In addition, with HFOT, diaphragmatic excursion increased (from [12.9±3.3] mm to [15.7±4.4] mm, P <0.001), but it did not change significantly during SBT with T-piece (from [13.4±3.3] mm to [13.6±3.3] mm). The diaphragmatic thickening fraction did not change during SBT either with T-piece or with HFOT.

Conclusion

In patients with prolonged mechanical ventilation, HFOT through tracheostomy compared with T-piece improves ventilation, pattern of breathing, and oxygenation without increasing the inspiratory muscle effort.

Trial Registration

Clinicaltrials.gov ldentifer: NCT04758910.

Diaphragm thickness modifications and associated factors during VA-ECMO for a cardiogenic shock: a cohort study

BACKGROUND

The incidence, causes and impact of diaphragm thickness evolution in veno-arterial extracorporeal membrane oxygenation (VA-ECMO) for cardiogenic shock are unknown. Our study investigates its evolution during the first week of VA-ECMO and its relationship with sweep gas flow settings.

METHODS

We conducted a prospective monocentric observational study in a 12-bed ICU in France, enrolling patients on the day of the VA-ECMO implantation. The diaphragm thickness and the diaphragm thickening fraction (as index of contractile activity, dTF; dTF < 20% defined a low contractile activity) were daily measured for one week using ultrasound. Factors associated with diaphragm thickness evolution (categorized as increased, stable, or atrophic based on > 10% modification from baseline to the last measurement), early extubation role (< day4), and patients outcome at 60 days were investigated. Changes in diaphragm thickness, the primary endpoint, was analysed using a mixed-effect linear model (MLM).

RESULTS

Of the 29 included patients, seven (23%) presented diaphragm atrophy, 18 remained stable (60%) and 4 exhibited an increase (17%). None of the 13 early-extubated patients experienced diaphragm atrophy, while 7 (46%) presented a decrease when extubated later (p-value = 0.008). Diaphragm thickness changes were not associated with the dTF (p-value = 0.13) but with sweep gas flow (Beta = - 3; Confidence Interval at 95% (CI) [- 4.8; - 1.2]. p-value = 0.001) and pH (Beta = - 2; CI [- 2.9; - 1]. p-value < 0.001) in MLM. The dTF remained low (< 20%) in 20 patients (69%) at the study's end and was associated with sweep gas flow evolution in MLM (Beta = - 2.8; 95% CI [- 5.2; - 0.5], p-value = 0.017). Odds ratio of death at 60 days in case of diaphragm atrophy by day 7 was 8.50 ([1.4-74], p = 0.029).

CONCLUSION

In our study, diaphragm thickness evolution was frequent and not associated with the diaphragm thickening fraction. Diaphragm was preserved from atrophy in case of early extubation with ongoing VA-ECMO assistance. Metabolic disorders resulting from organ failures and sweep gas flow were linked with diaphragm thickness evolution. Preserved diaphragm thickness in VA-ECMO survivors emphasizes the importance of diaphragm-protective strategies, including meticulous sweep gas flow titration.

Accuracy of respiratory muscle assessments to predict weaning outcomes: a systematic review and comparative meta-analysis

BACKGROUND

Several bedside assessments are used to evaluate respiratory muscle function and to predict weaning from mechanical ventilation in patients on the intensive care unit. It remains unclear which assessments perform best in predicting weaning success. The primary aim of this systematic review and meta-analysis was to summarize and compare the accuracy of the following assessments to predict weaning success: maximal inspiratory (PImax) and expiratory pressures, diaphragm thickening fraction and excursion (DTF and DE), end-expiratory (Tdiee) and end-inspiratory (Tdiei) diaphragm thickness, airway occlusion pressure (P0.1), electrical activity of respiratory muscles, and volitional and non-volitional assessments of transdiaphragmatic and airway opening pressures.

METHODS

Medline (via Pubmed), EMBASE, Web of Science, Cochrane Library and CINAHL were comprehensively searched from inception to 04/05/2023. Studies including adult mechanically ventilated patients reporting data on predictive accuracy were included. Hierarchical summary receiver operating characteristic (HSROC) models were used to estimate the SROC curves of each assessment method. Meta-regression was used to compare SROC curves. Sensitivity analyses were conducted by excluding studies with high risk of bias, as assessed with QUADAS-2. Direct comparisons were performed using studies comparing each pair of assessments within the same sample of patients.

RESULTS

Ninety-four studies were identified of which 88 studies (n = 6296) reporting on either PImax, DTF, DE, Tdiee, Tdiei and P0.1 were included in the meta-analyses. The sensitivity to predict weaning success was 63% (95% CI 47-77%) for PImax, 75% (95% CI 67-82%) for DE, 77% (95% CI 61-87%) for DTF, 74% (95% CI 40-93%) for P0.1, 69% (95% CI 13-97%) for Tdiei, 37% (95% CI 13-70%) for Tdiee, at fixed 80% specificity. Accuracy of DE and DTF to predict weaning success was significantly higher when compared to PImax (p = 0.04 and p < 0.01, respectively). Sensitivity and direct comparisons analyses showed that the accuracy of DTF to predict weaning success was significantly higher when compared to DE (p < 0.01).

CONCLUSIONS

DTF and DE are superior to PImax and DTF seems to have the highest accuracy among all included respiratory muscle assessments for predicting weaning success. Further studies aiming at identifying the optimal threshold of DTF to predict weaning success are warranted.

TRIAL REGISTRATION

PROSPERO CRD42020209295, October 15, 2020.

Rapid review of ventilator-induced diaphragm dysfunction

Ventilator-induced diaphragm dysfunction is gaining increased recognition. Evidence of diaphragm weakness can manifest within 12 h to a few days after the initiation of mechanical ventilation. Various noninvasive and invasive methods have been developed to assess diaphragm function. The implementation of diaphragm-protective ventilation strategies is crucial for preventing diaphragm injuries. Furthermore, diaphragm neurostimulation emerges as a promising and novel treatment option. In this rapid review, our objective is to discuss the current understanding of ventilator-induced diaphragm dysfunction, diagnostic approaches, and updates on strategies for prevention and management.

An Initial Investigation of Diaphragm Neurostimulation in Patients with Acute Respiratory Distress Syndrome

BACKGROUND

Lung protective ventilation aims at limiting lung stress and strain. By reducing the amount of pressure transmitted by the ventilator into the lungs, diaphragm neurostimulation offers a promising approach to minimize ventilator-induced lung injury. This study investigates the physiologic effects of diaphragm neurostimulation in acute respiratory distress syndrome (ARDS) patients. The hypothesis was that diaphragm neurostimulation would improve oxygenation, would limit the distending pressures of the lungs, and would improve cardiac output.

METHODS

Patients with moderate ARDS were included after 48 h of invasive mechanical ventilation and had a left subclavian catheter placed to deliver bilateral transvenous phrenic nerve stimulation. Two 60-min volume-controlled mechanical ventilation (control) sessions were interspersed by two 60-min diaphragm neurostimulation sessions delivered continually, in synchrony with the ventilator. Gas exchange, lung mechanics, chest electrical impedance tomography, and cardiac index were continuously monitored and compared across four sessions. The primary endpoint was the Pao2/fraction of inspired oxygen (Fio2) ratio at the end of each session, and the secondary endpoints were lung mechanics and hemodynamics.

RESULTS

Thirteen patients were enrolled but the catheter could not be inserted in one, leaving 12 patients for analysis. All sessions were conducted without interruption and well tolerated. The Pao2/Fio2 ratio did not change during the four sessions. Median (interquartile range) plateau pressure was 23 (20 to 31) cm H2O and 21 (17 to 25) cm H2O, driving pressure was 14 (12 to 18) cm H2O and 11 (10 to 13) cm H2O, and end-inspiratory transpulmonary pressure was 9 (5 to 11) cm H2O and 7 (4 to 11) cm H2O during mechanical ventilation alone and during mechanical ventilation + neurostimulation session, respectively. The dorsal/ventral ventilation surface ratio was 0.70 (0.54 to 0.91) when on mechanical ventilation and 1.20 (0.76 to 1.33) during the mechanical ventilation + neurostimulation session. The cardiac index was 2.7 (2.3 to 3.5) l · min-1 · m-2 on mechanical ventilation and 3.0 (2.4 to 3.9) l · min-1 · m-2 on mechanical ventilation + neurostimulation.

CONCLUSIONS

This proof-of-concept study showed the feasibility of short-term diaphragm neurostimulation in conjunction with mechanical ventilation in ARDS patients. Diaphragm neurostimulation was associated with positive effects on lung mechanics and on hemodynamics.

EDITOR’S PERSPECTIVE

Functional electrical stimulation cycling-based muscular evaluation method in mechanically ventilated patients

BACKGROUND

Intensive care acquired muscle weakness is a common feature in critically ill patients. Beyond the therapeutic uses, FES-cycling could represent a promising nonvolitional evaluation method for detecting acquired muscle weakness.

OBJECTIVES

To assess whether FES-cycling is able to identify muscle dysfunctions, and to evaluate the survival rate in patients with detected muscle dysfunction.

METHODS

A prospective observational study was carried out, with 29 critically ill patients and 20 healthy subjects. Maximum torque and power achieved were recorded, in addition to the stimulation cost, and patients were followed up for six months.

RESULTS

Torque (2.64 [1.53 to 4.81] vs 6.03 [4.56 to 6.73] Nm) and power (3.31 [2.33 to 6.37] vs 6.35 [5.22 to 10.70] watts) were lower and stimulation cost (22 915 [5069 to 37 750] vs 3411 [2080 to 4024] μC/W) was higher in patients compared to healthy people (p < 0.05). Surviving patients showed a nonsignificant difference in power and torque in relation to nonsurvivors (p > 0.05), but they had a lower stimulation cost (4462 [3598 to 11 788] vs 23 538 [10 164 to 39 836] μC/W) (p < 0.05). In total, 34% of all patients survived during the six months of follow-up. Furthermore, 62% of patients with a stimulation cost below 15 371 μC/W and 7% of patients with a stimulation cost above 15 371 μC/W survived.

CONCLUSIONS

FES-cycling has good sensitivity and specificity for detecting muscle disorders. Critical patients have low torque and power and a high stimulation cost. Stimulation cost is related to survival. A low stimulation cost was related to a 3 times greater chance of survival.

Lung, Pleura, and Diaphragm Point-of-Care Ultrasound

Thoracic Ultrasonography involves the ultrasonographic examination of the lungs, pleura, and diaphragm. This provides a plethora of clinical information during the point of care assessment of patients. The air filled lungs create consistent artifacts and careful examination and understanding of these artefactual signs can provide useful information on underlying clinicopathologic states. This review aims to provide a review of the ultrasound signs and features that can be seen in horacic ultrasonography and summarize the clinical evidence to support its use.