Dyspnea and respiratory muscles ultrasound to predict extubation failure

How to prevent and how to treat dyspnea in critically ill patients undergoing invasive mechanical ventilation

PURPOSE OF REVIEW

To summarize current data regarding the prevalence, risk factors, consequences, assessment and treatment of dyspnea in critically ill patients receiving invasive mechanical ventilation.

RECENT FINDINGS

In intubated patients, dyspnea is frequent, perceived as intense, and associated with unfavorable outcomes such as immediate and unbearable distress (e.g. fear of dying), prolonged weaning, and delayed severe psychological consequences ( i.e. posttraumatic stress disorders). In noncommunicative patients, dyspnea is named respiratory-related brain suffering (RRBS) and can be detected using dyspnea observations scales. Before initiating pharmacological treatments, nonpharmacological interventions may be tried as they are efficient to alleviate dyspnea.

SUMMARY

As opposed to pain, dyspnea has often been overlooked in terms of detection and management, resulting in its significant underestimation in daily practice. When it is diagnosed, dyspnea can be relieved through straightforward interventions, such as adjusting ventilator settings. Assessing dyspnea in patients undergoing invasive mechanically ventilated may be challenging, especially in noncommunicative patients (RRBS). Implementing a systematic dyspnea assessment in routine, akin to pain, could serve as a first step to reduce RRBS and prevent potential severe psychological consequences. In addition to pharmacological treatments like opioids, a promising approach is to modulate both the sensory (air on the face, trigeminal nerve stimulation) and the affective (relaxing music, hypnosis, directed empathy) components of dyspnea.

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.

The ability of diaphragmatic excursion after extubation to predict the need for resumption of ventilatory support in critically ill surgical patients

BACKGROUND

This study evaluated the ability of diaphragmatic excursion (DE), measured 2 h after extubation, to predict the need for resumption of ventilatory support within 48 h in surgical critically ill patients.

METHODS

This prospective observational study included adult surgical critically ill patients intubated for > 24 h and extubated after a successful spontaneous breathing trial. Sonographic measurement of the DE was performed 2 h after extubation. Patients were followed up for 48 h after extubation and were divided into reintubation group and successful weaning group. The primary outcome was DE's ability to predict the need for resumption of ventilatory support using the area under receiver characteristic curve (AUC) analysis.

RESULTS

Data from 70 patients were analyzed and 25/70 (36%) patients needed reintubation. DE was lower in the reintubation group than the successful weaning group. The AUC (95% confidence interval) for the ability of DE to predict the need for resumption of ventilatory support was 0.98(0.92-1.00) and 0.97(0.89-1.00) for the right and left side, respectively. At cutoff values of 20.8 and 19.8 mm, the right and left DE had positive predictive values of 92% and 88% and negative predictive values of 96% and 93%, respectively.

CONCLUSION

Among surgical critically ill patients undergoing weaning from invasive mechanical ventilation, DE obtained 2h after extubation is an accurate predictor for the need for resumption of ventilatory support. Diaphragmatic excursion < 20-21 mm could predict the need for resumption of ventilatory support with a positive predictive value of 88-92% and negative predictive value of 93-96%.

Effect of Implementing Respiratory Care Unit Ventilator Weaning Assessment Checklist on Weaning and Extubation Outcomes

BACKGROUND

Approximately 48% of patients with chronic respiratory disorders experience post-extubation respiratory failure necessitating noninvasive respiratory support or reintubation, which is linked to higher morbidity and mortality. So, it is necessary to determine patients' preparedness for weaning and extubation.

OBJECTIVES

To examine the effect of implementing respiratory care unit (RCC) ventilator weaning assessment checklist on weaning and extubation outcomes.

METHODS

Randomized controlled trial, carried out in 70 patients receiving mechanical ventilation from January 2023 to September 2023 at the respiratory intensive care units at Assiut University Hospital, Egypt. Patients were randomly assigned to a study and a usual care group, with 35 patients for each group. The usual care group weaned using the routine method, while the study group weaned using (RCC) ventilator weaning assessment checklist; the 2 groups were compared concerning weaning and extubation outcomes.

RESULTS

Compared to the usual care group, the study group's weaning success rate was significantly higher than that of the usual care group (88.6% vs 51.4%; P = .008), and extubation failure rate was significantly lower (17.1% vs 45.7%; P = .010).

CONCLUSIONS

Using RCC ventilator weaning assessment checklist improving weaning and extubation outcomes.

Decibel level of coughing as a predictor of extubation outcome in mechanically ventilated intensive care patients: A prospective, observational study

AIM

This study aims to evaluate the feasibility and clinical utility of measuring cough decibel level as predictive markers for extubation outcomes in mechanically ventilated patients.

DESIGN

A prospective observational study.

SETTING

Three interdisciplinary medical-surgical intensive care units across China.

MAIN OUTCOME MEASURES

The primary outcomes assessed were extubation results in patients. Secondary measures included the cough decibel level, semiquantitative cough intensity scores, and white card test results recorded prior to extubation.

RESULTS

A total of 71 patients were included, 55 patients were in the extubation success group and 16 in the failure group. The mean age was 78(71,83) years, mainly male (73.2 %). Despite the baseline characteristics being mostly consistent across both groups, significant differences were noted in duration of mechanical ventilation, and intensive care units and hospital stay. Remarkably, the cough decibel was substantially lower in the extubation failure group compared to the other group (78.69 ± 8.23 vs 92.28 ± 7.01 dB). The Receiver Operating Characteristic curve analysis revealed that a cough decibel below 85.77 dB is the optimal threshold for predicting extubation failure, exhibiting an 80 % sensitivity and 91.67 % specificity.

CONCLUSION

The study corroborates that the cough decibel level serves as a quantifiable metric in patients undergoing mechanical ventilation. It posits that the likelihood of extubation failure escalates when the cough decibel falls below 85.77 dB.

IMPLICATIONS FOR CLINICAL PRACTICE

Quantification of coughing capacity in decibels may be a good predictor of extubation outcome, thus offering assistance to healthcare professionals in evaluating the readiness of patients for extubation.

Predictors of weaning failure in ventilated intensive care patients: a systematic evidence map

BACKGROUND

Ventilator weaning is of great importance for intensive care patients in order to avoid complications caused by prolonged ventilation. However, not all patients succeed in weaning immediately. Their spontaneous breathing may be insufficient, resulting in extubation failure and the subsequent need for reintubation. To identify patients at high risk for weaning failure, a variety of potential predictors has already been examined in individual studies and meta-analyses over the last decades. However, an overview of all the predictors investigated is missing.

AIM

To provide an overview of empirically investigated predictors for weaning failure.

METHODS

A systematic evidence map was developed. To this end, we conducted a systematic search in the Medline, Cochrane, and CINAHL databases in December 2023 and added a citation search and a manual search in June 2024. Studies on predictors for weaning failure in adults ventilated in the intensive care unit were included. Studies on children, outpatients, non-invasive ventilation, or explanatory factors of weaning failure were excluded. Two reviewers performed the screening and data extraction independently. Data synthesis followed an inductive approach in which the predictors were thematically analyzed, sorted, and clustered.

RESULTS

Of the 1388 records obtained, 140 studies were included in the analysis. The 112 prospective and 28 retrospective studies investigated a total of 145 predictors. These were assigned to the four central clusters 'Imaging procedures' (n = 22), 'Physiological parameters' (n = 61), 'Scores and indices' (n = 53), and 'Machine learning models' (n = 9). The most frequently investigated predictors are the rapid shallow breathing index, the diaphragm thickening fraction, the respiratory rate, the P/F ratio, and the diaphragm excursion.

CONCLUSION

Predictors for weaning failure are widely researched. To date, 145 predictors have been investigated with varying intensity in 140 studies that are in line with the current weaning definition. It is no longer just individual predictors that are investigated, but more comprehensive assessments, indices and machine learning models in the last decade. Future research should be conducted in line with international weaning definitions and further investigate poorly researched predictors. Registration, Protocol: https://doi.org/10.17605/OSF.IO/2KDYU.

The ratio of parasternal intercostal muscle-thickening fraction-to-diaphragm thickening fraction for predicting weaning failure

BACKGROUND

Diaphragm dysfunction is associated with weaning outcomes in mechanical ventilation patients, in the case of diaphragm dysfunction, the accessory respiratory muscles would be recruited. The main purpose of this study is to explore the performance of parasternal intercostal muscle thickening fraction in relation to diaphragmatic thickening fraction ratio (TFic1/TFdi2) for predicting weaning outcomes, and compare its accuracy with D-RSBI in predicting weaning failure.

MATERIALS AND METHODS

We prospectively enrolled consecutive patients from 7/2022-5/2023. We measured TFic, TFdi, and diaphragmatic excursion (DE3) by ultrasound and calculated the TFic/TFdi ratio and diaphragmatic rapid shallow breathing index (D-RSBI4). Receiver-operator characteristic (ROC5) curves evaluated the accuracy of the TFic/TFdi ratio and D-RSBI in predicting weaning failure.

RESULTS

161 were included in the final analysis, 114 patients (70.8%) were successfully weaned from mechanical ventilation. The TFic/TFdi ratio (AUROC = 0.887 (95% CI: 0.821-0.953)) was superior to the D-RSBI (AUROC = 0.875 (95% CI: 0.807-0.944)) for predicting weaning failure.

CONCLUSIONS

The TFic/TFdi ratio predicted weaning failure with high accuracy and outperformed the D-RSBI.

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.

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.

Analysis and applications of respiratory surface EMG: report of a round table meeting

Surface electromyography (sEMG) can be used to measure the electrical activity of the respiratory muscles. The possible applications of sEMG span from patients suffering from acute respiratory failure to patients receiving chronic home mechanical ventilation, to evaluate muscle function, titrate ventilatory support and guide treatment. However, sEMG is mainly used as a monitoring tool for research and its use in clinical practice is still limited-in part due to a lack of standardization and transparent reporting. During this round table meeting, recommendations on data acquisition, processing, interpretation, and potential clinical applications of respiratory sEMG were discussed. This paper informs the clinical researcher interested in respiratory muscle monitoring about the current state of the art on sEMG, knowledge gaps and potential future applications for patients with respiratory failure.

Dyspnea and Dyspnea-Associated Anxiety in the ICU Patient Population: A Narrative Review for CL Psychiatrists

BACKGROUND

Consultation-liaison psychiatrists frequently address dyspnea in intensive care unit (ICU) patients. Dyspnea is common in this patient population, but is frequently misunderstood and underappreciated in noncommunicative ICU patients.

OBJECTIVE

This paper provides an updated review on dyspnea specifically in the ICU population, including its pathophysiology and management, pharmacological and nonpharmacological, aimed at consultation-liaison psychiatrists consulting in ICU.

METHODS

A literature review was conducted with PubMed, querying published articles for topics associated with dyspnea and dyspnea-associated anxiety in ICU patient populations. When literature in ICU populations was limited, information was deduced from dyspnea and anxiety management from non-ICU populations. Articles discussing the definition of dyspnea, mechanistic pathways, screening tools, and pharmacologic and nonpharmacologic management were included.

RESULTS

A reference guide was created to help consultation-liaison psychiatrists and intensivists in the screening and treatment of dyspnea and dyspnea-associated anxiety in critically ill patients.

CONCLUSIONS

Dyspnea is frequently associated with anxiety, prolonged days on mechanical ventilation, and worse quality of life after discharge. It can also increase the risk of posttraumatic stress disorder post-ICU discharge. However, it is not routinely screened for, identified, or addressed in the ICU. This manuscript provides an updated review on dyspnea and dyspnea-associated anxietyin the ICU population, including its pathophysiology and management, and offers a useful reference for consultation-liaison psychiatrists to provide treatment recommendations.

Effect of a pre-emptive 2-hour session of high-flow nasal oxygen on postoperative oxygenation after major gynaecologic surgery: a randomised clinical trial

BACKGROUND

We aimed at determining whether a 2-h session of high-flow nasal oxygen (HFNO) immediately after extubation improves oxygen exchange after major gynaecological surgery in the Trendelenburg position in adult female patients.

METHODS

In this single-centre, open-label, randomised trial, patients who underwent major gynaecological surgery were randomised to HFNO or conventional oxygen treatment with a Venturi mask. The primary outcome was the Pao2/FiO2 ratio after 2 h of treatment. Secondary outcomes included lung ultrasound score, diaphragm thickening fraction, dyspnoea, ventilatory frequency, Paco2, the percentage of patients with impaired gas exchange (Pao2/FiO2 ≤40 kPa) after 2 h of treatment, and postoperative pulmonary complications at 30 days.

RESULTS

A total of 83 patients were included (42 in the HFNO group and 41 in the conventional treatment group). After 2 h of treatment, median (inter-quartile range) Pao2/FiO2 was 52.9 (47.9-65.2) kPa in the HFNO group and 45.7 (36.4 -55.9) kPa in the conventional treatment group (mean difference 8.7 kPa [95% CI: 3.4 to 13.9], P=0.003). The lung ultrasound score was lower in the HFNO group than in the conventional treatment group (9 [6-10] vs 12 [10-14], P<0.001), mostly because of the difference of the score in dorsal areas (7 [6-8] vs 10 [9-10], P<0.001). The percentage of patients with impaired gas exchange was lower in the HFNO group than in the conventional treatment group (5% vs 37%, P<0.001). All other secondary outcomes were not different between groups.

CONCLUSIONS

In patients who underwent major gynaecological surgery, a pre-emptive 2-h session of HFNO after extubation improved postoperative oxygen exchange and reduced atelectasis compared with a conventional oxygen treatment strategy.

CLINICAL TRIAL REGISTRATION

NCT04566419.

Lung aeration estimated by chest electrical impedance tomography and lung ultrasound during extubation

BACKGROUND

This study hypothesized that patients with extubation failure exhibit a loss of lung aeration and heterogeneity in air distribution, which could be monitored by chest EIT and lung ultrasound. Patients at risk of extubation failure were included after a successful spontaneous breathing trial. Lung ultrasound [with calculation of lung ultrasound score (LUS)] and chest EIT [with calculation of the global inhomogeneity index, frontback center of ventilation (CoV), regional ventilation delay (RVD) and surface available for ventilation] were performed before extubation during pressure support ventilation (H0) and two hours after extubation during spontaneous breathing (H2). EIT was then repeated 6 h (H6) after extubation. EIT derived indices and LUS were compared between patients successfully extubated and patients with extubation failure.

RESULTS

40 patients were included, of whom 12 (30%) failed extubation. Before extubation, when compared with patients with successful extubation, patients who failed extubation had a higher LUS (19 vs 10, p = 0.003) and a smaller surface available for ventilation (352 vs 406 pixels, p = 0.042). After extubation, GI index and LUS were higher in the extubation failure group, whereas the surface available for ventilation was lower. The RVD and the CoV were not different between groups.

CONCLUSION

Before extubation, a loss of lung aeration was observed in patients who developed extubation failure afterwards. After extubation, this loss of lung aeration persisted and was associated with regional lung ventilation heterogeneity. Trial registration Clinical trials, NCT04180410, Registered 27 November 2019-prospectively registered, https://clinicaltrials.gov/ct2/show/NCT04180410 .

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

TRIAL REGISTRATION

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

Physiological effects of awake prone position in acute hypoxemic respiratory failure

BACKGROUND

The effects of awake prone position on the breathing pattern of hypoxemic patients need to be better understood. We conducted a crossover trial to assess the physiological effects of awake prone position in patients with acute hypoxemic respiratory failure.

METHODS

Fifteen patients with acute hypoxemic respiratory failure and PaO2/FiO2 < 200 mmHg underwent high-flow nasal oxygen for 1 h in supine position and 2 h in prone position, followed by a final 1-h supine phase. At the end of each study phase, the following parameters were measured: arterial blood gases, inspiratory effort (ΔPES), transpulmonary driving pressure (ΔPL), respiratory rate and esophageal pressure simplified pressure-time product per minute (sPTPES) by esophageal manometry, tidal volume (VT), end-expiratory lung impedance (EELI), lung compliance, airway resistance, time constant, dynamic strain (VT/EELI) and pendelluft extent through electrical impedance tomography.

RESULTS

Compared to supine position, prone position increased PaO2/FiO2 (median [Interquartile range] 104 mmHg [76-129] vs. 74 [69-93], p < 0.001), reduced respiratory rate (24 breaths/min [22-26] vs. 27 [26-30], p = 0.05) and increased ΔPES (12 cmH2O [11-13] vs. 9 [8-12], p = 0.04) with similar sPTPES (131 [75-154] cmH2O s min-1 vs. 105 [81-129], p > 0.99) and ΔPL (9 [7-11] cmH2O vs. 8 [5-9], p = 0.17). Airway resistance and time constant were higher in prone vs. supine position (9 cmH2O s arbitrary units-3 [4-11] vs. 6 [4-9], p = 0.05; 0.53 s [0.32-61] vs. 0.40 [0.37-0.44], p = 0.03). Prone position increased EELI (3887 arbitrary units [3414-8547] vs. 1456 [959-2420], p = 0.002) and promoted VT distribution towards dorsal lung regions without affecting VT size and lung compliance: this generated lower dynamic strain (0.21 [0.16-0.24] vs. 0.38 [0.30-0.49], p = 0.004). The magnitude of pendelluft phenomenon was not different between study phases (55% [7-57] of VT in prone vs. 31% [14-55] in supine position, p > 0.99).

CONCLUSIONS

Prone position improves oxygenation, increases EELI and promotes VT distribution towards dependent lung regions without affecting VT size, ΔPL, lung compliance and pendelluft magnitude. Prone position reduces respiratory rate and increases ΔPES because of positional increases in airway resistance and prolonged expiratory time. Because high ΔPES is the main mechanistic determinant of self-inflicted lung injury, caution may be needed in using awake prone position in patients exhibiting intense ΔPES. Clinical trail registeration: The study was registered on clinicaltrials.gov (NCT03095300) on March 29, 2017.

Interventions Relieving Dyspnea in Intubated Patients Show Responsiveness of the Mechanical Ventilation-Respiratory Distress Observation Scale

Rationale: Breathing difficulties are highly stressful. In critically ill patients, they are associated with an increased risk of posttraumatic manifestations. Dyspnea, the corresponding symptom, cannot be directly assessed in noncommunicative patients. This difficulty can be circumvented using observation scales such as the mechanical ventilation-respiratory distress observation scale (MV-RDOS). Objective: To investigate the performance and responsiveness of the MV-RDOS to infer dyspnea in noncommunicative intubated patients. Methods: Communicative and noncommunicative patients exhibiting breathing difficulties under mechanical ventilation were prospectively included and assessed using a dyspnea visual analog scale, MV-RDOS, EMG activity of alae nasi and parasternal intercostals, and EEG signatures of respiratory-related cortical activation (preinspiratory potentials). Inspiratory-muscle EMG and preinspiratory cortical activities are surrogates of dyspnea. Assessments were conducted at baseline, after adjustment of ventilator settings, and, in some cases, after morphine administration. Measurements and Main Results: Fifty patients (age, 67 [(interquartile interval [IQR]), 61-76] yr; Simplified Acute Physiology Score II, 52 [IQR, 35-62]) were included, 25 of whom were noncommunicative. Relief occurred in 25 (50%) patients after ventilator adjustments and in 21 additional patients after morphine administration. In noncommunicative patients, MV-RDOS score decreased from 5.5 (IQR, 4.2-6.6) at baseline to 4.2 (IQR, 2.1-4.7; P < 0.001) after ventilator adjustments and 2.5 (IQR, 2.1-4.2; P = 0.024) after morphine administration. MV-RDOS and alae nasi/parasternal EMG activities were positively correlated (ρ = 0.41 and 0.37, respectively). MV-RDOS scores were higher in patients with EEG preinspiratory potentials (4.9 [IQR, 4.2-6.3] vs. 4.0 [IQR, 2.1-4.9]; P = 0.002). Conclusions: The MV-RDOS seems able to detect and monitor respiratory symptoms reasonably well in noncommunicative intubated patients. Clinical trial registered with www.clinicaltrials.gov (NCT02801838).

Managing respiratory muscle weakness during weaning from invasive ventilation

Weaning is a critical stage of an intensive care unit (ICU) stay, in which the respiratory muscles play a major role. Weakness of the respiratory muscles, which is associated with significant morbidity in the ICU, is not limited to atrophy and subsequent dysfunction of the diaphragm; the extradiaphragmatic inspiratory and expiratory muscles also play important parts. In addition to the well-established deleterious effect of mechanical ventilation on the respiratory muscles, other risk factors such as sepsis may be involved. Weakness of the respiratory muscles can be suspected visually in a patient with paradoxical movement of the abdominal compartment. Measurement of maximal inspiratory pressure is the simplest way to assess respiratory muscle function, but it does not specifically take the diaphragm into account. A cut-off value of -30 cmH2O could identify patients at risk for prolonged ventilatory weaning; however, ultrasound may be better for assessing respiratory muscle function in the ICU. Although diaphragm dysfunction has been associated with weaning failure, this diagnosis should not discourage clinicians from performing spontaneous breathing trials and considering extubation. Recent therapeutic developments aimed at preserving or restoring respiratory muscle function are promising.

Respective Effects of Helmet Pressure Support, Continuous Positive Airway Pressure, and Nasal High-Flow in Hypoxemic Respiratory Failure: A Randomized Crossover Clinical Trial

Rationale: The respective effects of positive end-expiratory pressure (PEEP) and pressure support delivered through the helmet interface in patients with hypoxemia need to be better understood. Objectives: To assess the respective effects of helmet pressure support (noninvasive ventilation [NIV]) and continuous positive airway pressure (CPAP) compared with high-flow nasal oxygen (HFNO) on effort to breathe, lung inflation, and gas exchange in patients with hypoxemia (PaO2/FiO2 ⩽ 200). Methods: Fifteen patients underwent 1-hour phases (constant FiO2) of HFNO (60 L/min), helmet NIV (PEEP = 14 cm H2O, pressure support = 12 cm H2O), and CPAP (PEEP = 14 cm H2O) in randomized sequence. Measurements and Main Results: Inspiratory esophageal (ΔPES) and transpulmonary pressure (ΔPL) swings were used as surrogates for inspiratory effort and lung distension, respectively. Tidal Volume (Vt) and end-expiratory lung volume were assessed with electrical impedance tomography. ΔPES was lower during NIV versus CPAP and HFNO (median [interquartile range], 5 [3-9] cm H2O vs. 13 [10-19] cm H2O vs. 10 [8-13] cm H2O; P = 0.001 and P = 0.01). ΔPL was not statistically different between treatments. PaO2/FiO2 ratio was significantly higher during NIV and CPAP versus HFNO (166 [136-215] and 175 [158-281] vs. 120 [107-149]; P = 0.002 and P = 0.001). NIV and CPAP similarly increased Vt versus HFNO (mean change, 70% [95% confidence interval (CI), 17-122%], P = 0.02; 93% [95% CI, 30-155%], P = 0.002) and end-expiratory lung volume (mean change, 198% [95% CI, 67-330%], P = 0.001; 263% [95% CI, 121-407%], P = 0.001), mostly due to increased aeration/ventilation in dorsal lung regions. During HFNO, 14 of 15 patients had pendelluft involving >10% of Vt; pendelluft was mitigated by CPAP and further by NIV. Conclusions: Compared with HFNO, helmet NIV, but not CPAP, reduced ΔPES. CPAP and NIV similarly increased oxygenation, end-expiratory lung volume, and Vt, without affecting ΔPL. NIV, and to a lesser extent CPAP, mitigated pendelluft. Clinical trial registered with clinicaltrials.gov (NCT04241861).

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

Background

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

Method

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

Result

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

Conclusion

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

Diaphragm Ultrasound in Critically Ill Patients on Mechanical Ventilation—Evolving Concepts

Mechanical ventilation (MV) is a life-saving respiratory support therapy, but MV can lead to diaphragm muscle injury (myotrauma) and induce diaphragmatic dysfunction (DD). DD is relevant because it is highly prevalent and associated with significant adverse outcomes, including prolonged ventilation, weaning failures, and mortality. The main mechanisms involved in the occurrence of myotrauma are associated with inadequate MV support in adapting to the patient’s respiratory effort (over- and under-assistance) and as a result of patient-ventilator asynchrony (PVA). The recognition of these mechanisms associated with myotrauma forced the development of myotrauma prevention strategies (MV with diaphragm protection), mainly based on titration of appropriate levels of inspiratory effort (to avoid over- and under-assistance) and to avoid PVA. Protecting the diaphragm during MV therefore requires the use of tools to monitor diaphragmatic effort and detect PVA. Diaphragm ultrasound is a non-invasive technique that can be used to monitor diaphragm function, to assess PVA, and potentially help to define diaphragmatic effort with protective ventilation. This review aims to provide clinicians with an overview of the relevance of DD and the main mechanisms underlying myotrauma, as well as the most current strategies aimed at minimizing the occurrence of myotrauma with special emphasis on the role of ultrasound in monitoring diaphragm function.

Highlights from the Respiratory Failure and Mechanical Ventilation 2022 Conference

The Respiratory Intensive Care Assembly of the European Respiratory Society gathered in Berlin to organise the second Respiratory Failure and Mechanical Ventilation Conference in June 2022. The conference covered several 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. Lectures delivered during the event have been summarised by Early Career Members of the Assembly and take-home messages highlighted.

Update on Lean Body Mass Diagnostic Assessment in Critical Illness

Acute critical illnesses can alter vital functions with profound biological, biochemical, metabolic, and functional modifications. Despite etiology, patient's nutritional status is pivotal to guide metabolic support. The assessment of nutritional status remains complex and not completely elucidated. Loss of lean body mass is a clear marker of malnutrition; however, the question of how to investigate it still remains unanswered. Several tools have been implemented to measure lean body mass, including a computed tomography scan, ultrasound, and bioelectrical impedance analysis, although such methods unfortunately require validation. A lack of uniform bedside measurement tools could impact the nutrition outcome. Metabolic assessment, nutritional status, and nutritional risk have a pivotal role in critical care. Therefore, knowledge about the methods used to assess lean body mass in critical illnesses is increasingly required. The aim of the present review is to update the scientific evidence regarding lean body mass diagnostic assessment in critical illness to provide the diagnostic key points for metabolic and nutritional support.

Methodological and Clinimetric Evaluation of Inspiratory Respiratory Muscle Ultrasound in the Critical Care Setting: A Systematic Review and Meta-Analysis

OBJECTIVE

Significant variations exist in the use of respiratory muscle ultrasound in intensive care with no society-level consensus on the optimal methodology. This systematic review aims to evaluate, synthesize, and compare the clinimetric properties of different image acquisition and analysis methodologies.

DATA SOURCES

Systematic search of five databases up to November 24, 2021.

STUDY SELECTION

Studies were included if they enrolled at least 50 adult ICU patients, reported respiratory muscle (diaphragm or intercostal) ultrasound measuring either echotexture, muscle thickness, thickening fraction, or excursion, and evaluated at least one clinimetric property. Two independent reviewers assessed titles, abstracts, and full text against eligibility.

DATA EXTRACTION

Study demographics, ultrasound methodologies, and clinimetric data.

DATA SYNTHESIS

Sixty studies, including 5,025 patients, were included with 39 studies contributing to meta-analyses. Most commonly measured was diaphragm thickness (DT) or diaphragm thickening fraction (DTF) using a linear transducer in B-mode, or diaphragm excursion (DE) using a curvilinear transducer in M-mode. There are significant variations in imaging methodology and acquisition across all studies. Inter- and intrarater measurement reliabilities were generally excellent, with the highest reliability reported for DT (ICC, 0.98; 95% CI, 0.94-0.99). Pooled data demonstrated acceptable to excellent accuracy for DT, DTF, and DE to predicting weaning outcome after 48 to 72 hours postextubation (DTF AUC, 0.79; 95% CI, 0.73-0.85). DT imaging was responsive to change over time. Only three eligible studies were available for intercostal muscles. Intercostal thickening fraction was shown to have excellent accuracy of predicting weaning outcome after 48-hour postextubation (AUC, 0.84; 95% CI, 0.78-0.91).

CONCLUSIONS

Diaphragm muscle ultrasound is reliable, valid, and responsive in ICU patients, but significant variation exists in the imaging acquisition and analysis methodologies. Future work should focus on developing standardized protocols for ultrasound imaging and consider further research into the role of intercostal muscle imaging.

Interpretable recurrent neural network models for dynamic prediction of the extubation failure risk in patients with invasive mechanical ventilation in the intensive care unit

Background

Clinical decision of extubation is a challenge in the treatment of patient with invasive mechanical ventilation (IMV), since existing extubation protocols are not capable of precisely predicting extubation failure (EF). This study aims to develop and validate interpretable recurrent neural network (RNN) models for dynamically predicting EF risk.

Methods

A retrospective cohort study was conducted on IMV patients from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. Time series with a 4-h resolution were built for all included patients. Two types of RNN models, the long short-term memory (LSTM) and the gated recurrent unit (GRU), were developed. A stepwise logistic regression model was used to select key features for developing light-version RNN models. The RNN models were compared to other five non-temporal machine learning models. The Shapley additive explanations (SHAP) value was applied to explain the influence of the features on model prediction.

Results

Of 8,599 included patients, 2,609 had EF (30.3%). The area under receiver operating characteristic curve (AUROC) of LSTM and GRU showed no statistical difference on the test set (0.828 vs. 0.829). The light-version RNN models based on the 26 features selected out of a total of 89 features showed comparable performance as their corresponding full-version models. Among the non-temporal models, only the random forest (RF) (AUROC: 0.820) and the extreme gradient boosting (XGB) model (AUROC: 0.823) were comparable to the RNN models, but their calibration was deviated.

Conclusions

The RNN models have excellent predictive performance for predicting EF risk and have potential to become real-time assistant decision-making systems for extubation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13040-022-00309-7.

Myths and Misconceptions of Airway Pressure Release Ventilation: Getting Past the Noise and on to the Signal

In the pursuit of science, competitive ideas and debate are necessary means to attain knowledge and expose our ignorance. To quote Murray Gell-Mann (1969 Nobel Prize laureate in Physics): "Scientific orthodoxy kills truth". In mechanical ventilation, the goal is to provide the best approach to support patients with respiratory failure until the underlying disease resolves, while minimizing iatrogenic damage. This compromise characterizes the philosophy behind the concept of "lung protective" ventilation. Unfortunately, inadequacies of the current conceptual model-that focuses exclusively on a nominal value of low tidal volume and promotes shrinking of the "baby lung" - is reflected in the high mortality rate of patients with moderate and severe acute respiratory distress syndrome. These data call for exploration and investigation of competitive models evaluated thoroughly through a scientific process. Airway Pressure Release Ventilation (APRV) is one of the most studied yet controversial modes of mechanical ventilation that shows promise in experimental and clinical data. Over the last 3 decades APRV has evolved from a rescue strategy to a preemptive lung injury prevention approach with potential to stabilize the lung and restore alveolar homogeneity. However, several obstacles have so far impeded the evaluation of APRV's clinical efficacy in large, randomized trials. For instance, there is no universally accepted standardized method of setting APRV and thus, it is not established whether its effects on clinical outcomes are due to the ventilator mode per se or the method applied. In addition, one distinctive issue that hinders proper scientific evaluation of APRV is the ubiquitous presence of myths and misconceptions repeatedly presented in the literature. In this review we discuss some of these misleading notions and present data to advance scientific discourse around the uses and misuses of APRV in the current literature.

Dyspnea and the electromyographic activity of inspiratory muscles during weaning from mechanical ventilation

Rationale

Dyspnea, a key symptom of acute respiratory failure, is not among the criteria for spontaneous breathing trial (SBT) failure. Here, we sought (1) to determine whether dyspnea is a reliable failure criterion for SBT failure; (2) to quantify the relationship between dyspnea and the respective electromyographic activity of the diaphragm (EMGdi), the parasternal (EMGpa) and the Alae nasi (EMGan).

Methods

Mechanically ventilated patients undergoing an SBT were included. Dyspnea intensity was measured by the Dyspnea-Visual Analogic Scale (Dyspnea-VAS) at the initiation and end of the SBT. During the 30-min SBT or until SBT failure, the EMGdi was continuously measured with a multi-electrode nasogastric catheter and the EMGan and EMGpa with surface electrodes.

Results

Thirty-one patients were included, SAPS 2 (median [interquartile range]) 53 (37‒74), mechanically ventilated for 6 (3‒10) days. Seventeen patients (45%) failed the SBT. The increase in Dyspnea-VAS along the SBT was higher in patients who failed (6 [4‒8] cm) than in those who passed (0 [0‒1] cm, p = 0.01). The area under the receiver operating characteristics curve for Dyspnea-VAS was 0.909 (0.786–1.032). The increase in Dyspnea-VAS was significantly correlated to the increase in EMGan (Rho = 0.42 [0.04‒0.70], p < 0.05), but not to the increase in EMGpa (Rho = − 0.121 [− 0.495 to − 0.290], p = 0.555) and EMGdi (Rho = − 0.26 [− 0.68 to 0.28], p = 0.289).

Conclusion

Dyspnea is a reliable criterion of SBT failure, suggesting that Dyspnea-VAS could be used as a monitoring tool of the SBT. In addition, dyspnea seems to be more closely related to the electromyographic activity of the Alae nasi than of the diaphragm.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-022-01025-5.

Respiratory distress observation scales to predict weaning outcome

Background

Whether dyspnea is present before starting a spontaneous breathing trial (SBT) and whether it may affect the outcome of the SBT is unknown. Mechanical Ventilation—Respiratory Distress Observation Scale (MV-RDOS) has been proposed as a reliable surrogate of dyspnea in non-communicative intubated patients. In the present study, we sought (1) to describe the evolution of the MV-RDOS during a SBT and (2) to investigate whether MV-RDOS can predict the outcome of the SBT.

Methods

Prospective, single-center study in a twenty-two bed ICU in a tertiary center. Patients intubated since more 48 h who had failed a first SBT were eligible if they meet classical readiness to wean criteria. The MV-RDOS was assessed before, at 2-min, 15-min and 30-min (end) of the SBT. The presence of clinically important dyspnea was inferred by a MV-RDOS value ≥  2.6.

Results

Fifty-eight patients (age 63 [51–70], SAPS II 66 [51–76]; med [IQR]) were included. Thirty-three (57%) patients failed the SBT, whose 18 (55%) failed before 15-min. Twenty-five (43%) patients successfully passed the SBT. A MV-RDOS ≥ 2.6 was present in ten (17%) patients before to start the SBT. All these ten patients subsequently failed the SBT. A MV-RDOS ≥ 2.6 at 2-min predicted a SBT failure with a 51% sensibility and a 88% specificity (AUC 0.741 95% confidence interval [CI] 0.616–0.866, p = 0.002). Best cut-off value at 2-min was 4.3 and predicted SBT failure with a 27% sensibility and a 96% specificity.

Conclusion

Despite patients met classical readiness to wean criteria, respiratory distress assessed with the MV-RDOS was frequent at the beginning of SBT. Measuring MV-RDOS before to initiate a SBT could avoid undue procedure and reduce patient’s exposure to unnecessary mechanical ventilation weaning failure and distress.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-022-04028-7.

Chronic obstructive pulmonary disease assessment test for the measurement of deterioration and recovery of health status of patients undergoing lung surgery

Background

Patients with early lung cancer often undergo surgery. However, surgery usually results in a decline in health‐related quality of life (HRQL). Several questionnaires have previously been used to assess HRQL but some are impractical for clinical use. The chronic obstructive pulmonary disease assessment test (CAT) is simple and has been widely used in respiratory diseases but not for lung cancer. We therefore conducted this study to clarify the role of the CAT in postoperative deterioration and recovery of HRQL.

Methods

Fifty‐five patients who underwent lung resection were recruited into the study. Cardiopulmonary exercise tests and respiratory muscle strength were performed 1 week before surgery (pre‐OP) and at post‐OP 1 month. HRQL was assessed through the CAT and European Organization for Research and Treatment of Cancer Quality of Life Core Questionnaire (EORTC QLQ‐C30) 1 week pre‐OP and post‐OP 1 and at 2 months.

Results

Fifteen (27.3%) patients underwent wedge resection, four (7.3%) underwent segmentectomy, and 36 (65.5%) underwent lobectomy. After lobectomy, exercise capacity decreased significantly. The deterioration of CAT symptoms (cough, phlegm, chest tightness, dyspnea, activity, confidence, sleep disturbance, and lack of energy) was more prominent in patients who had undergone lobectomy than wedge resection. Based on the EORTC QLQ‐C30, physical, role function, fatigue, pain, sleep disturbance, dyspnea, and global health status worsened significantly, whereas there was no significant difference in other symptoms. HRQL recovered at post‐OP 2 months in patients who had undergone wedge resection but not lobectomy.

Conclusions

Postoperative HRQL and exercise capacity in patients were significantly reduced, especially those who had undergone lobectomy. The CAT significantly reflected postoperative changes in HRQL.

Dyspnoea and clinical outcome in critically ill patients receiving noninvasive support for COVID-19 respiratory failure: post hoc analysis of a randomised clinical trial

In non-COVID-19 acute hypoxaemic respiratory failure, the entity of dyspnoea has been associated with severity of hypoxaemia, and represents a factor predicting noninvasive ventilation (NIV) failure, the need for endotracheal intubation and mortality [1].

In #COVID19 patients, presence of moderate-to-severe dyspnoea is a marker of disease severity correlated to clinical outcomeshttps://bit.ly/3Bp2G1b

Handgrip strength to predict extubation outcome: a prospective multicenter trial

BACKGROUND

ICU-acquired weakness (ICUAW) has been shown to be associated with prolonged duration of mechanical ventilation and extubation failure. It is usually assessed through Medical Research Council (MRC) score, a time-consuming score performed by physiotherapists. Handgrip strength (HG) can be monitored very easily at the bedside. It has been shown to be a reproducible and reliable marker of global muscular strength in critical care patients. We sought to test if muscular weakness, as assessed by handgrip strength, was associated with extubation outcome.

METHODS

Prospective multicenter trial over an 18 months period in six mixed ICUs. Adults receiving mechanical ventilation for at least 48 h were eligible. Just before weaning trial, HG, Maximal Inspiratory Pressure (MIP), Peak Cough Expiratory Flow (PCEF) and Medical Research Council (MRC) score were registered. The attending physicians were unaware of the tests results and weaning procedures were conducted according to guidelines. Occurrence of unscheduled reintubation, non-invasive ventilation (NIV) or high-flow nasal continuous oxygen (HFNC) because of respiratory failure within 7 days after extubation defined extubation failure. The main outcome was the link between HG and extubation outcome.

RESULTS

233 patients were included. Extubation failure occurred in 51 (22.5%) patients, 39 (17.2%) required reintubation. Handgrip strength was 12 [6-20] kg and 12 [8-20] kg, respectively, in extubation success and failure (p = 0.85). There was no association between extubation outcome and MRC score, MIP or PCEF. Handgrip strength was well correlated with MRC score (r = 0.718, p < 0.0001). ICU and hospital length of stay were significantly higher in the subset of patients harboring muscular weakness as defined by handgrip performed at the first weaning trial (respectively, 15 [10-25] days vs. 11 [7-17] days, p = 0.001 and 34 [19-66] days vs. 22 [15-43] days, p = 0.002).

CONCLUSION

No association was found between handgrip strength and extubation outcome. Whether this was explained by the appropriateness of the tool in this specific setting, or by the precise impact of ICUAW on extubation outcome deserves to be further evaluated. Trial registration Clinical Trials; NCT02946502, 10/27/2016, URL: https://clinicaltrials.gov/ct2/results?cond=&term=gripwean&cntry=&state=&city=&dist=.