Does obesity impact on weaning from invasive ventilation: a secondary analysis of the WEAN SAFE study

Annals of Intensive Care volume 15, Article number: 164 (2025) Published: 21 October 2025

Objective

To understand the impact of obesity on outcomes of weaning from invasive mechanical ventilation (MV).

Methods

The study population consisted of patients enrolled in the WEAN SAFE study. We defined 4 groups based on body mass index (BMI), namely: Normal weight (BMI 18.5–24.9 kg/m²), Overweight (BMI 25–29.9 kg/m²), Obesity Class I (BMI 30–34.9 kg/m²), and obesity classes II and III (BMI ≥ 35 kg/m²). The primary outcome was the rate of successful extubation in patients in each BMI group. Secondary outcomes included the ICU and hospital survival, and PEEP levels at time of weaning eligibility in patients in each BMI group.

Results

In the study population, 1728 (38.2%) were of normal weight, 1395 (30.8%) were overweight, 590 (13.1%) were class I Obesity, and 431 (9.5%) were obesity classes II and III. Patients with obesity were more likely to be female, to be a medical admission, and to have comorbidities. Patients with grade II-III obesity had lower levels of sedation, later timing of the first separation attempt, longer time to weaning success, they received more noninvasive ventilation post extubation, and they had a longer ICU stay. In contrast, weaning success, and ICU and hospital mortality rates were not different in obese patients. There was no independent relationship between obesity and weaning delay, weaning success, or with overall survival outcomes. Higher PEEP at weaning eligibility was associated with weaning failure in normal and overweight patients but not in patients with obesity.

Conclusions

Patients with obesity had a more complex and longer weaning process, but obesity per se was not independently associated with adverse weaning outcomes.

 

 

 

Can we predict the future of respiratory failure prediction?

Critical Care volume 29, Article number: 253 (2025)

Background

Mortality in patients with acute respiratory failure remains high. Predicting progression of acute respiratory failure may be critical to improving patient outcomes. Machine learning, a subset of artificial intelligence is a rapidly expanding area, which is being integrated into several areas of clinical medicine. This manuscript will address the knowledge gap in predicting the onset and progression of respiratory failure, provide a review of existing prognostic strategies, and provide a clinical perspective on the implementation and future integration of machine learning into clinical care.

Main body

Existing strategies for predicting respiratory failure, such as prediction scores and biomarkers, offer both strengths and limitations. While these tools provide some prognostic value, machine learning presents a promising, data-driven approach to prognostication in the intensive care unit. Machine learning has already shown success in various areas of clinical medicine, although relatively few algorithms target respiratory failure prediction specifically. As machine learning grows in the context of respiratory failure, outcomes such as the need for invasive mechanical ventilation and escalation of respiratory support (e.g. non-invasive ventilation) have been identified as key targets. However, the development and implementation of machine learning models in clinical care involves complex challenges. Future success will depend on rigorous model validation, clinician collaboration, thoughtful trial design, and the application of implementation science to ensure integration into clinical care.

Conclusion

Machine learning holds promise for optimizing treatment strategies and potentially improving outcomes in respiratory failure. However, further research and development are necessary to fully realize its potential in clinical practice.

 

Impact of frailty and older age on weaning from invasive ventilation: a secondary analysis of the WEAN SAFE study

Annals of Intensive Care volume 15, Article number: 13 (2025)

Published: 20 January 2025

Objective

To understand the impact of both frailty and chronologic age on outcomes of weaning from invasive mechanical ventilation (MV).

Methods

The study population consisted of patients enrolled in the ‘WorldwidE. AssessmeNt of Separation of pAtients From ventilatory assistancE (WEAN SAFE) study. We defined 4 non-overlapping groups, namely: ‘frail’ (clinical frailty scale [CFS] score > 4; age < 80 years); ‘elderly’ (CFS ≤ 4; age ≥ 80y), ‘frail \elderly’ (CFS > 4; age ≥ 80 years), and a ‘not frail or elderly’ population. The primary outcome was the impact of frailty and older age on delayed weaning and failed weaning from invasive MV. Secondary outcomes included the impact of frailty and age on ICU and hospital survival.

Results

In the study population, 760 (17%) were frail, while 360 (8%) were elderly, 197 (4%) were frail and elderly, while 3,176 (70%) were not frail or elderly. The frail and elderly cohorts were more likely to be female, had hypoxemic/hypercapnic respiratory failure or sepsis, and had more comorbidities. The proportion of delayed weaning and of failed weaning from invasive MV was significantly higher in the frail (28 and 23%), the elderly (25 and 19%), and the frail and elderly groups (22% and 25%), compared to the not frail or elderly population (12% and 13%, P < 0.01). ICU and hospital mortality was higher in the frail (21 and 33%), the elderly (19 and 31%), and the frail and elderly groups (26 and 46%), compared to the not frail or elderly population (12% and 18%, P < 0.001). In multivariate analyses, there was an independent association between frailty and delayed weaning initiation and weaning failure. Old age was independently associated with risk of weaning failure.

Conclusions

Frailty status had a more consistent impact than older age on weaning outcomes. However, overall outcomes in these cohorts are encouraging once separation attempts have been initiated.

 

 

Derivation and external validation of predictive models for invasive mechanical ventilation in intensive care unit patients with COVID-19

Annals of Intensive Care volume 14, Article number: 129 (2024) Published: 21 August 2024

Background

This study aimed to develop prognostic models for predicting the need for invasive mechanical ventilation (IMV) in intensive care unit (ICU) patients with COVID-19 and compare their performance with the Respiratory rate-OXygenation (ROX) index.

Methods

A retrospective cohort study was conducted using data collected between March 2020 and August 2021 at three hospitals in Rio de Janeiro, Brazil. ICU patients aged 18 years and older with a diagnosis of COVID-19 were screened. The exclusion criteria were patients who received IMV within the first 24 h of ICU admission, pregnancy, clinical decision for minimal end-of-life care and missing primary outcome data. Clinical and laboratory variables were collected. Multiple logistic regression analysis was performed to select predictor variables. Models were based on the lowest Akaike Information Criteria (AIC) and lowest AIC with significant p values. Assessment of predictive performance was done for discrimination and calibration. Areas under the curves (AUC)s were compared using DeLong’s algorithm. Models were validated externally using an international database.

Results

Of 656 patients screened, 346 patients were included; 155 required IMV (44.8%), 191 did not (55.2%), and 207 patients were male (59.8%). According to the lowest AIC, arterial hypertension, diabetes mellitus, obesity, Sequential Organ Failure Assessment (SOFA) score, heart rate, respiratory rate, peripheral oxygen saturation (SpO2), temperature, respiratory effort signals, and leukocytes were identified as predictors of IMV at hospital admission. According to AIC with significant p values, SOFA score, SpO2, and respiratory effort signals were the best predictors of IMV; odds ratios (95% confidence interval): 1.46 (1.07–2.05), 0.81 (0.72–0.90), 9.13 (3.29–28.67), respectively. The ROX index at admission was lower in the IMV group than in the non-IMV group (7.3 [5.2–9.8] versus 9.6 [6.8–12.9], p < 0.001, respectively). In the external validation population, the area under the curve (AUC) of the ROX index was 0.683 (accuracy 63%), the AIC model showed an AUC of 0.703 (accuracy 69%), and the lowest AIC model with significant p values had an AUC of 0.725 (accuracy 79%).

Conclusions

In the development population of ICU patients with COVID-19, SOFA score, SpO2, and respiratory effort signals predicted the need for IMV better than the ROX index. In the external validation population, although the AUCs did not differ significantly, the accuracy was higher when using SOFA score, SpO2, and respiratory effort signals compared to the ROX index. This suggests that these variables may be more useful in predicting the need for IMV in ICU patients with COVID-19.

Critical Care Bulletin - July 2024

 

Breathlessness assessment, management and impact in the intensive care unit: a rapid review and narrative synthesis

 

by Ben R. Richardson, Maxens Decavèle, Alexandre Demoule, Fliss E. M. Murtagh and Miriam J. Johnson 

 

Annals of Intensive Care volume 14, Article number: 107, Published: 05 July 2024

 

Background

Adults in the intensive care unit (ICU) commonly experience distressing symptoms and other concerns such as pain, delirium, and breathlessness. Breathlessness management is not supported by any ICU guidelines, unlike other symptoms.

Aim

To review the literature relating to (i) prevalence, intensity, assessment, and management of breathlessness in critically ill adults in the ICU receiving invasive and non-invasive mechanical ventilation (NIV) and high-flow oxygen therapy, (HFOT), (ii) the impact of breathlessness on ICU patients with regard to engagement with rehabilitation.

Methods

A rapid review and narrative synthesis using the Cochrane Methods Group Recommendations was conducted and reported in accordance with PRISMA. All study designs investigating breathlessness in adult ICU patients receiving either invasive mechanical ventilation (IMV), NIV or HFOT were eligible. PubMed, MEDLINE, The Cochrane Library and CINAHL databased were searched from June 2013 to June 2023. Studies were quality appraised.

Results

19 studies representing 2822 ICU patients were included (participants mean age 48 years to 71 years; proportion of males 43–100%). The weighted mean prevalence of breathlessness in ICU patients receiving IMV was 49% (range 34–66%). The proportion of patients receiving NIV self-reporting moderate to severe dyspnoea was 55% prior to initiation. Breathlessness assessment tools included visual analogue scale, (VAS), numerical rating scale, (NRS) and modified BORG scale, (mBORG). In patients receiving NIV the highest reported median (interquartile range [IQR]) VAS, NRS and mBORG scores were 6.2cm (0–10 cm), 5 (2–7) and 6 (2.3–7) respectively (moderate to severe breathlessness). In patients receiving either NIV or HFOT the highest reported median (IQR) VAS, NRS and mBORG scores were 3 cm (0–6 cm), 8 (5–10) and 4 (3–5) respectively.

Conclusion

Breathlessness in adults receiving IMV, NIV or HFOT in the ICU is prevalent and clinically important with median intensity ratings indicating the presence of moderate to severe symptoms.

 

Inhaled drug delivery: a randomized study in intubated patients with healthy lungs

 

by Jonathan Dugernier, Déborah Le Pennec, Guillaume Maerckx, Laurine Allimonnier, Michel Hesse, Diego Castanares-Zapatero, Virginie Depoortere, Laurent Vecellio, Gregory Reychler, Jean-Bernard Michotte, Pierre Goffette, Marie-Agnes Docquier, Christian Raftopoulos, François Jamar, Pierre-François Laterre, Stephan Ehrmann…

 

Annals of Intensive Care volume 13, Article number: 125 (2023) Published: 11 December 2023

 

Background

The administration technique for inhaled drug delivery during invasive ventilation remains debated. This study aimed to compare in vivo and in vitro the deposition of a radiolabeled aerosol generated through four configurations during invasive ventilation, including setups optimizing drug delivery.

Methods

Thirty-one intubated postoperative neurosurgery patients with healthy lungs were randomly assigned to four configurations of aerosol delivery using a vibrating-mesh nebulizer and specific ventilator settings: (1) a specific circuit for aerosol therapy (SCAT) with the nebulizer placed at 30 cm of the wye, (2) a heated-humidified circuit switched off 30 min before the nebulization or (3) left on with the nebulizer at the inlet of the heated-humidifier, (4) a conventional circuit with the nebulizer placed between the heat and moisture exchanger filter and the endotracheal tube. Aerosol deposition was analyzed using planar scintigraphy.

Results

A two to three times greater lung delivery was measured in the SCAT group, reaching 19.7% (14.0–24.5) of the nominal dose in comparison to the three other groups (p < 0.01). Around 50 to 60% of lung doses reached the outer region of both lungs in all groups. Drug doses in inner and outer lung regions were significantly increased in the SCAT group (p < 0.01), except for the outer right lung region in the fourth group due to preferential drug trickling from the endotracheal tube and the trachea to the right bronchi. Similar lung delivery was observed whether the heated humidifier was switched off or left on. Inhaled doses measured in vitro correlated with lung doses (R = 0.768, p < 0.001).

Conclusion

Optimizing the administration technique enables a significant increase in inhaled drug delivery to the lungs, including peripheral airways. Before adapting mechanical ventilation, studies are required to continue this optimization and to assess its impact on drug delivery and patient outcome in comparison to more usual settings.

 

 

 

 

Prevalence and impact of early prone position on 30-day mortality in mechanically ventilated patients with COVID-19: a nationwide cohort study

 

by Lars Engerström, Johan Thermaenius, Johan Mårtensson, Anders Oldner, Johan Petersson, Jessica Kåhlin and Emma Larsson 

 

Critical Care volume 26, Article number: 264 (2022) 

 

Background

COVID-19 ARDS shares features with non-COVID ARDS but also demonstrates distinct physiological differences. Despite a lack of strong evidence, prone positioning has been advocated as a key therapy for COVID-19 ARDS. The effects of prone position in critically ill patients with COVID-19 are not fully understood, nor is the optimal time of initiation defined. In this nationwide cohort study, we aimed to investigate the association between early initiation of prone position and mortality in mechanically ventilated COVID-19 patients with low oxygenation on ICU admission.

Methods

Using the Swedish Intensive Care Registry (SIR), all Swedish ICU patients ≥ 18 years of age with COVID-19 admitted between March 2020, and April 2021 were identified. A study-population of patients with PaO2/FiO2 ratio ≤ 20 kPa on ICU admission and receiving invasive mechanical ventilation within 24 h from ICU admission was generated. In this study-population, the association between early use of prone position (within 24 h from intubation) and 30-day mortality was estimated using univariate and multivariable logistic regression models.

Results

The total study cohort included 6350 ICU patients with COVID-19, of whom 46.4% were treated with prone position ventilation. Overall, 30-day mortality was 24.3%. In the study-population of 1714 patients with lower admission oxygenation (PaO2/FiO2 ratio ≤ 20 kPa), the utilization of early prone increased from 8.5% in March 2020 to 48.1% in April 2021. The crude 30-day mortality was 27.2% compared to 30.2% in patients not receiving early prone positioning. We found no significant association between early use of prone positioning and survival.

Conclusions

During the first three waves of the COVID-19 pandemic, almost half of the patients in Sweden were treated with prone position ventilation. We found no association between early use of prone positioning and survival in patients on mechanical ventilation with severe hypoxemia on ICU admission. To fully elucidate the effect and timing of prone position ventilation in critically ill patients with COVID-19 further studies are desirable.

 

 

Early intubation and patient-centered outcomes in septic shock: a secondary analysis of a prospective multicenter study

 

by Ricard Mellado-Artigas, Carlos Ferrando, Frédéric Martino, Agathe Delbove, Bruno L. Ferreyro, Cedric Darreau, Sophie Jacquier, Laurent Brochard and Nicolas Lerolle 

 

Critical Care volume 26, Article number: 163 (2022) Published: 07 June 2022

 

Purpose

Despite the benefits of mechanical ventilation, its use in critically ill patients is associated with complications and had led to the growth of noninvasive techniques. We assessed the effect of early intubation (first 8 h after vasopressor start) in septic shock patients, as compared to non-early intubated subjects (unexposed), regarding in-hospital mortality, intensive care and hospital length of stay.

Methods

This study involves secondary analysis of a multicenter prospective study. To adjust for baseline differences in potential confounders, propensity score matching was carried out. In-hospital mortality was analyzed in a time-to-event fashion, while length of stay was assessed as a median difference using bootstrapping.

Results

A total of 735 patients (137 intubated in the first 8 h) were evaluated. Propensity score matching identified 78 pairs with similar severity and characteristics on admission. Intubation was used in all patients in the early intubation group and in 27 (35%) subjects beyond 8 h in the unexposed group. Mortality occurred in 35 (45%) and in 26 (33%) subjects in the early intubation and unexposed groups (hazard ratio 1.44 95% CI 0.86–2.39, p = 0.16). ICU and hospital length of stay were not different among groups [9 vs. 5 (95% CI 1 to 7) and 14 vs. 16 (95% CI − 7 to 8) days]. All sensitivity analyses confirmed the robustness of our findings.

Conclusions

An early approach to invasive mechanical ventilation did not improve outcomes in this matched cohort of patients. The limited number of patients included in these analyses out the total number included in the study may limit generalizability of these findings.

 

 

 

Critical Care Bulletin - February 2022

 

Tracheostomy timing and clinical outcomes in ventilated COVID-19 patients: a systematic review and meta-analysis

 

by Yun Ji, Yumin Fang, Baoli Cheng, Libin Li and Xiangming Fang 

 

Critical Care volume 26, Article number: 40 (2022)

 

Background

The association of tracheostomy timing and clinical outcomes in ventilated COVID-19 patients remains controversial. We performed a meta-analysis to evaluate the impact of early tracheostomy compared to late tracheostomy on COVID-19 patients’ outcomes.

Methods

We searched Medline, Embase, Cochrane, and Scopus database, along with medRxiv, bioRxiv, and Research Square, from December 1, 2019, to August 24, 2021. Early tracheostomy was defined as a tracheostomy conducted 14 days or less after initiation of invasive mechanical ventilation (IMV). Late tracheostomy was any time thereafter. Duration of IMV, duration of ICU stay, and overall mortality were the primary outcomes of the meta-analysis. Pooled odds ratios (OR) or the mean differences (MD) with 95%CIs were calculated using a random-effects model.

Results

Fourteen studies with a cumulative 2371 tracheostomized COVID-19 patients were included in this review. Early tracheostomy was associated with significant reductions in duration of IMV (2098 patients; MD − 9.08 days, 95% CI − 10.91 to − 7.26 days, p < 0.01) and duration of ICU stay (1224 patients; MD − 9.41 days, 95% CI − 12.36 to − 6.46 days, p < 0.01). Mortality was reported for 2343 patients and was comparable between groups (OR 1.09, 95% CI 0.79–1.51, p = 0.59).

Conclusions

The results of this meta-analysis suggest that, compared with late tracheostomy, early tracheostomy in COVID-19 patients was associated with shorter duration of IMV and ICU stay without modifying the mortality rate. These findings may have important implications to improve ICU availability during the COVID-19 pandemic.