Reappraisal of Ventilator-Free Days in Critical Care Research

A Comparative Study of Fentanyl Versus Hydromorphone in Mechanically Ventilated Intensive Care Unit Patients

BACKGROUND

Although the SCCM PADIS guidelines suggest fentanyl or hydromorphone infusions for analgesia during mechanical ventilation (MV), few studies compare patient-centered outcomes.

OBJECTIVE

This study evaluated therapeutic outcomes and adverse effects of fentanyl and hydromorphone in MV intensive care unit patients.

METHODS

This single-center, retrospective cohort study evaluated adult MV patients who were intubated for 1 to 14 days and received either hydromorphone or fentanyl infusion for analgesia, while targeting light sedation. The primary endpoint was 28-day MV-free survival. Select secondary endpoints included cumulative and hourly opioid doses during MV, duration of MV, and time within goal pain and sedation score ranges during MV. Multivariate regression analysis was performed for patients intubated more than 72 hours.

RESULTS

A total of 238 patients were included; 144 received fentanyl and 94 received hydromorphone. Baseline characteristics were similar between groups with a median age of 66 years, weight 78 kg, and 33% female. Median 28-day MV-free survival was 22 and 21 days for the fentanyl and hydromorphone groups, respectively (P = 0.36). Patients given fentanyl received higher cumulative opioid doses, expressed in fentanyl equivalents, during MV compared to hydromorphone-treated patients, 4241 (interquartile range [IQR] 1817-8146) mcg and 2448 (IQR 1012-4926) mcg (P < 0.001), respectively, and higher hourly average doses, 55 (IQR 39-75) mcg/h and 37 (IQR 29-51) mcg/h (P < 0.001), respectively.

CONCLUSION AND RELEVANCE

There was no difference in 28-day MV-free survival with fentanyl- and hydromorphone-based analgesia, but hydromorphone was associated with lower cumulative and hourly opioid requirements.

Role of Proton Pump Inhibitor as Stress Ulcer Prophylaxis in Sick Children: A Randomized Controlled Trial

OBJECTIVE

To evaluate the efficacy of intravenous pantoprazole as a stress ulcer prophylaxis in sick children to prevent gastrointestinal (GI) bleeding.

METHODS

A randomized controlled trial included children aged one-month to 18 years requiring intensive care. Participants were randomly assigned to receive intravenous pantoprazole or a placebo (normal saline) daily. The primary outcome was the incidence of GI bleeding (clinically significant or overt). Secondary outcomes were the median time of onset of GI bleeding, incidence of ventilator-associated pneumonia (VAP), duration of hospitalization, organ dysfunction scores, and all-cause mortality.

RESULTS

A total of 151 and 150 children were allocated to group A (pantoprazole) and group B (placebo), respectively. No significant difference was observed in the incidence of GI bleeding between the groups (group A: 21/151 vs group B: 19/150 [RR (95% CI) 1.03 (0.18, 5.82), P = 0.985]. Comparable results were observed for clinically significant GI bleeding (1.3% vs 0.6%; RR (95% CI) 0.54 (0.21, 1.28); P = 0.653 and overt GI bleeding [12.6% vs 12%; RR (95% CI) 0.98 (0.39, 2.23); P value = 0.313]. On multivariate analysis, there was a reduced incidence of GI bleeding in children with coagulopathy in pantoprazole group (n = 29) as compared to placebo (n = 25) [RR (95%CI) 0.52 (0.32, 0.87); P = 0.022].

CONCLUSION

Among critically ill children, pantoprazole prophylaxis did not reduce the incidence of gastrointestinal bleeding, although, a notable decrease in gastrointestinal bleeding was observed in children with coagulopathy.

TRIALS REGISTRY

Clinical Trials Registry of India, Ref no: CTRI/2021/08/035785, Date of registration:18th August 2021.

Cytomegalovirus reactivation in the lower respiratory tract as an independent risk factor for mortality in critically Ill patients

BACKGROUND

The clinical significance of cytomegalovirus reactivation in the lower respiratory tract (LRT) of critically ill patients remains unclear. We aimed to investigate the association between cytomegalovirus reactivation detected in LRT and intensive care unit (ICU) prognosis.

METHODS

This study included critically ill patients admitted to a medical ICU at a tertiary referral center in South Korea between January 2021 and June 2023. Cytomegalovirus load in LRT samples collected via bronchoscopy was measured within 7 days of admission. Detection of cytomegalovirus DNA in LRT was defined as reactivation. Associations between cytomegalovirus reactivation and ICU, in-hospital, 30-day, and 90-day mortality were assessed using multivariable Fine-Gray model adjusted for major clinical factors.

RESULTS

Of the 322 patients (median age 68 years, 66.8% male), 145 (45%) had cytomegalovirus reactivation in the LRT. Cytomegalovirus reactivation was independently associated with increased ICU (adjusted subdistribution hazard ratio [aSHR], 2.28; 95% confidence interval [CI], 1.46-3.56), in-hospital (aSHR, 2.00; 95% CI, 1.44-2.78), 30-day (aSHR, 2.11; 95% CI, 1.42-3.13), and 90-day mortality (aSHR, 2.05; 95% CI, 1.45-2.88). Anti-cytomegalovirus therapy was significantly associated with reduced ICU mortality in patients with radiologic findings suggestive of cytomegalovirus pneumonia (P for interaction = 0.001), but was linked to increased mortality in patients with positive bacterial cultures (P for interaction = 0.002).

CONCLUSION

Cytomegalovirus reactivation in the LRT is associated with poor outcomes in critically ill patients. Anti-cytomegalovirus therapy was not associated with overall survival outcomes; however, the subgroup with radiologic findings of cytomegalovirus pneumonia suggested benefits, while the subgroup with bacterial co-infections suggested harmful effects. Randomized controlled trials are needed.

Impact of Benzodiazepines on Outcomes of Mechanically Ventilated Pediatric Intensive Care Patients: A Retrospective Cohort Study

IMPORTANCE

Benzodiazepines are the most frequently used sedatives in PICUs, but they are increasingly associated with negative outcomes. Understanding their impact on patient outcomes is critical to provide better sedative management for patients.

OBJECTIVE

Our objective was to determine the impact of midazolam and lorazepam on clinical outcomes among subjects requiring mechanical ventilation in the PICU. We hypothesized that subjects receiving benzodiazepines for tolerance of mechanical ventilation will demonstrate worse clinical outcomes when compared with those not receiving benzodiazepines.

DESIGN

Single-center, retrospective cohort study.

SETTING AND PARTICIPANTS

PICU of a tertiary-care medical center. One thousand fifty-four pediatric participants requiring invasive mechanical ventilation between June 2018 and December 2022. Participants were categorized into those who received benzodiazepine-inclusive sedation regimens (n = 747) and those who received nonbenzodiazepine regimens (n = 307).

INTERVENTIONS

None.

MAIN OUTCOMES AND MEASURES

Subjects were sorted into groups of benzodiazepine-sedative regimens (midazolam and lorazepam, only lorazepam) or nonbenzodiazepine-sedation regimens. The primary outcome was ventilator-free days (VFDs). Statistical analysis was performed using multivariable linear regression and propensity-score matching.

RESULTS

Subjects receiving continuous and/or intermittent benzodiazepines had fewer VFDs compared with the nonbenzodiazepine group (median 21.0 vs. 26.7; p < 0.001). The benzodiazepine group had fewer ICU-free and hospital-free days, higher delirium scores, and a greater need for withdrawal-tapering medications. This was redemonstrated in subjects only receiving intermittent benzodiazepines as well. Younger subjects were more likely to receive benzodiazepines.

CONCLUSIONS AND RELEVANCE

Our study demonstrates an association between children receiving both continuous and intermittent benzodiazepine sedation and worse clinical outcomes. These patients have fewer VFDs and longer length of stay, higher doses of nonbenzodiazepine sedatives, and increased need for withdrawal tapering medications and antipsychotics. It is unclear in this retrospective study if the outcomes were worse because the subjects received benzodiazepines or because subjects receiving benzodiazepines were sicker and thus required benzodiazepines in their analgosedative regimen. Further investigation is warranted into the impact of benzodiazepines on patient outcomes, nonpharmacologic management of sedation, improvement in bedside assessment of analgosedation, and optimal balance between over- and under-sedation.

The Prevalence and Outcome of Acute Hypoxemic Respiratory Failure (PANDORA) Study in Mechanically Ventilated Children: Prospective Multicenter Epidemiology in Spain, 2019-2021

OBJECTIVES

To describe the epidemiology and outcome of children with acute hypoxemic respiratory failure (AHRF) and/or pediatric acute respiratory distress syndrome (PARDS).

DESIGN

Prospective, observational study in six nonconsecutive 2-month blocks form October 2019 to September 2021.

SETTING

A network of 22 PICUs in Spain.

PATIENTS

Consecutive children (7 d to 15 yr old) with a diagnosis of AHRF, defined by Pao2/Fio2 ratio less than or equal to 300 mm Hg, who needed invasive mechanical ventilation (IMV) using positive end-expiratory pressure (PEEP) greater than or equal to 5 cm H2O and Fio2 greater than or equal to 0.3.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The primary outcomes were AHRF prevalence and PICU mortality. The secondary outcomes were the prevalence of IMV with PARDS (IMV-PARDS) and the use of adjunctive therapies. There were 6545 PICU admissions: 1374 (21%) underwent IMV and 181 (2.8%) had AHRF. Ninety-one patients (1.4% of PICU admissions, 6.6% of IMV cases, and 50.3% of AHRF cases) met the Second Pediatric Acute Lung Injury Consensus Conference IMV-PARDS criteria. At baseline, mean (± sd) tidal volume was 7.4 ± 1.8 mL/kg ideal body weight, PEEP 8.4 ± 3.1 cm H2O, Fio2 0.68 ± 0.23, and plateau pressure 25.7 ± 6.3 cm H2O. Unlike patients with PARDS, adjunctive therapies were used infrequently in non-PARDS AHRF patients. AHRF patients without PARDS had more ventilator-free days than PARDS patients (16.4 ± 9.4 vs. 11.2 ± 10.5; p = 0.002). All-cause PICU mortality in AHRF cases was higher in PARDS vs. non-PARDS patients (30.8% [95% CI, 21.5-41.3] vs. (14.4% [95% CI, 7.9-23.4]; p = 0.01).

CONCLUSIONS

In our 2019-2021 PICU population, the prevalence of AHRF is 2.8% of IMV cases. Of such patients, the prevalence of PARDS was 50.3%, and there was a 30.8% mortality, which was higher than in cases of AHRF without PARDS.

Tackling the small imbalanced horizontal dataset regressions by Stability Selection and SMOGN: a case study of ventilation-free days prediction in the pediatric intensive care unit and the importance of PRISM

OBJECTIVE

The regression of small imbalanced horizontal datasets is an important problem in bioinformatics due to rare but vital data points impacting model performance. Most clinical studies suffer from imbalance in their distribution which impacts the learning ability of regression or classification models. The imbalance once combined with the small number of samples reduces the prediction performance. An improvement in the trainability of small imbalanced datasets hugely improves the potency of current prediction models that rely on a small set of valuable expensive samples.

MATERIALS AND METHODS

A method called Stability Selection has been used to overcome the high dimensionality problem, which arises when the sample sizes are relatively small compared to the number of features. The method was used to improve the performance of the Synthetic Minority Over-Sampling Technique for Regression with Gaussian Noise (SMOGN), an imbalance removal algorithm. To test the new pipeline, a small imbalanced cohort of pediatric ICU patients was used to predict the number of Ventilator-Free Days (VFD) a patient may experience for an admission period of 28 days due to respiratory illnesses.

RESULTS

Our model demonstrated its effectiveness by overcoming label imbalance while predicting almost all the non-surviving patients in the test dataset using Stability Selection before applying SMOGN. Our study also highlighted the importance of Pediatrics Risk of Mortality (PRISM) as a powerful VFD predictor if combined with other clinical features.

CONCLUSION

This paper shows how a hybrid strategy of Stability Selection, SMOGN, and regression can improve the outcome of highly imbalanced datasets and reduce the probability of highly expensive false negative detections in severe acute respiratory disease syndrome cases. The proposed modeling pipeline can reduce the overall VFD regression error but is also expandable to other regressable features. We also showed the importance of PRISM as a strong VFD predictor.

A randomised, open-label trial of nebulised unfractionated heparin in patients mechanically ventilated for COVID-19

Nebulised unfractionated heparin (UFH) might reduce time to ventilator separation in patients with COVID-19 by reducing virus infectivity, pulmonary coagulopathy, and inflammation, but clinical trial data are limited. Between 1 July 2020 and 23 March 2022, we conducted, at two hospitals in Victoria, Australia, a randomised, parallel-group, open-label, controlled trial of nebulised UFH. Eligible patients were aged 18 years or more, intubated, under intensive care unit management, had a PaO2 to FIO2 ratio of 300 or less, had acute opacities affecting at least one lung quadrant and attributed to COVID-19, and were polymerase chain reaction-positive for SARS-CoV-2 or had further testing planned. The target sample size was 270, however, the trial was stopped due to slow recruitment. There were 50 enrolments, all of whom were analysed. The median age was 55 (interquartile range (IQR) 46-64) years, 28 (56%) were males, and 46 (92%) had acute respiratory distress syndrome. Twenty-seven (54%) were randomised to nebulised heparin and 23 (46%) to standard care. Nebulised UFH was administered to the heparin group on 6 (IQR 4-10) days; median daily dose of 83 (IQR 75-88) kIU. The primary outcome, time to separation from invasive ventilation to day 28 adjusted for the competing risk of death, was not significantly different between groups but took numerically longer in the nebulised heparin group (12.0, standard deviation (SD) 10.4 days versus 7.4, SD 6.9 days; hazard ratio (HR) 0.56, 95% confidence interval (CI) 0.31 to 1.01, P = 0.052). One patient died by day 28 in each group, fewer than expected. Time to separation from invasive ventilation among survivors to day 28 occurred more quickly than expected in the standard care group and was, without correction for multiple comparisons, significantly slower in the heparin group (11.3, SD 10.0 days, n = 26 versus 6.4, SD 5.2 days, n = 22; HR 0.52, 95% CI 0.30 to 0.92, P = 0.024). Nebulised heparin did not reduce time to ventilator separation in intubated adult patients with COVID-19. The study is limited by the small sample size and potential for sampling bias. Further study is required.

Total bilirubin as a marker for hemolysis and outcome in patients with severe ARDS treated with veno-venous ECMO

BACKGROUND

Hemolysis is a common complication in critically ill patients with sepsis, acute respiratory distress syndrome (ARDS) or therapy with extracorporeal membrane oxygenation (ECMO). Heme degradation product bilirubin might accumulate in conditions of significant hemolysis. In patients with ARDS and therapy with veno-venous ECMO (vvECMO), the prognostic potential of elevated initial total bilirubin (tBili) was investigated.

METHODS

Retrospective analysis of patients with ARDS and vvECMO-therapy (n = 327) admitted to a tertiary ARDS center. A tBili cut-off value was determined by binary recursive partitioning. Baseline characteristics were compared and relevant variables were included in a multivariate logistic regression model with backward variable selection. Primary endpoint was survival within 28 days analyzed with Kaplan-Meier-curves and cox regression. Secondary endpoints included failure free composites for organ dysfunction, renal replacement therapy (RRT), vasopressor therapy and ECMO within 28 days and were compared using competing risk regression analysis.

RESULTS

A cut-off value of 3.6mg/dl divided the cohort for ICU mortality (tBili ≤ 3.6mg/dl: 46% (n = 273) vs. tBili > 3.6mg/dl: 78% (n = 54), p < 0.001). The group with tBili > 3.6mg/dl showed a higher 28-day mortality (HR 3.03 [95%CI 2.07-4.43], p < 0.001) and significantly lower chances of successful recovery from organ dysfunction (subdistribution hazard ratio (SHR) 0.29 [0.13-0.66], p < 0.001), RRT (SHR 0.34 [0.14-0.85], p = 0.02), and ECMO (SHR 0.46 [0.25-0.86], p = 0.015) compared to the group with tBili ≤ 3.6mg/dl. Recovery from vasopressor therapy did not differ between groups (SHR 0.63 [0.32-1.24], p = 0.18).

CONCLUSION

Patients with ARDS, vvECMO-therapy and tBili > 3.6mg/dl had a higher mortality and lower chances for recovery from organ dysfunction, RRT, and ECMO within 28 days. The tBili-cut-off value may be useful to identify patients at risk for unfavorable outcomes.

Efficacy of hemoadsorption in the severe course of COVID-19

Introduction

Insufficiencies of the majority of targeted therapies for the most severe, life-threatening forms of COVID-19 warrant alternative, adjuvant treatment options for enhanced life maintenance that include extracorporeal blood purification and homeostasis support. The goal of the current study is to evaluate the clinical efficacy of hemoadsorption with mesoporous hypercrosslinked polystyrene beads (Efferon CT single-use cartridge) in an expanded cohort of patients with severe and critical COVID-19 resistant to antibody therapies and requiring post-therapy invasive mechanical lung ventilation (MLV) versus parameter-matched control group with no hemoadsorption.

Materials and methods

A single-center cohort study (NCT06402279) enrolled patients from October 2020 to February 2022: the Efferon CT group (non-responders to anti-cytokine antibody therapy requiring IMV, hemadsorption, and standard treatment, n = 65) and retrospectively acquired propensity-matched control group (no hemadsorption, standard treatment only, n = 65).

Results

This observational study revealed the capability of Efferon CT hemoadsorption to safely, rapidly, and significantly reduce the need for norepinephrine, increase the oxygenation index, prevent the sepsis-associated AKI, decrease the development of multiorgan failure, and restore the immune system balance by decreasing pro-inflammatory IL-6, ferritin levels, and neutrophil-to-lymphocyte ratio.

Conclusion

The clinical efficiency of hemoadsorption using Efferon CT was confirmed by the resolution of acute respiratory failure in 54% of patients, significantly increasing the number of days without mechanical ventilation and increasing early the index of oxygenation. Most importantly, the hemoadsorption with Efferon CT was safe and resulted in a significant decrease in the mortality of severe COVID-19 patients.

Clinical trial registration

www.clinicaltrials.gov, Identifier NCT06402279.

Hospital-Acquired Complications in Critically Ill Children and PICU Length of Stay, Duration of Respiratory Support, and Economics: Propensity Score Matching in a Single-Center Cohort, 2015-2020

OBJECTIVES

To identify the health and economic costs of hospital-acquired complications (HACs) in children who require PICU admission.

DESIGN

Propensity score matched cohort study analyzing routinely collected medical and costing data collected by the health service over 6 years (2015-2020).

SETTING

Tertiary referral PICU in Queensland, Australia.

PATIENTS

All children admitted to the PICU were included.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We assessed ventilator- and respiratory support-free days at 30 days post-PICU admission, length of PICU stay, prevalence of individual HACs, and attributable healthcare costs. A total of 8437 admissions, representing 6054 unique patients were included in the analysis. Median (interquartile range) for cohort age was 2.1 years (0.4-7.7 yr), 56% were male. Healthcare-associated infections contributed the largest proportion of HACs (incidence rate per 100 bed days, 46.5; 95% CI, 29.5-47.9). In the propensity score matched analyses (total 3852; 1306 HAC and 1371 no HAC), HAC events were associated with reduced ventilator- (adjusted subhazard ratio [aSHR], 0.88 [95% CI, 0.82-0.94]) and respiratory support-free days (aSHR, 0.74 [95% CI, 0.69-0.79]) and increased PICU length of stay (aSHR, 0.63 [95% CI, 0.58-0.68]). Healthcare costs for children who developed a HAC were higher compared with children with no HAC, with mean additional cost ranging from Australian dollar (A$) 77,825 (one HAC [95% CI, $57,501-98,150]) to $310,877 (≥ 4 HACs [95% CI, $214,572-407,181]; in 2022, the average conversion of A$ to U.S. dollar was 0.74).

CONCLUSIONS

In our PICU (2015-2020), the burden of HAC for critically ill children was highest for healthcare-associated infections. Further high-quality evidence regarding HAC prevention and prospective risk assessment could lead to improved patient outcomes and reduced costs.

Timing of Extubation in Adult Patients with Acute Brain Injury

Rationale: Whether extubation immediately after a successful spontaneous breathing trial is associated with clinical benefits in adult patients with acute brain injury is unknown. Objectives: We sought to estimate the association between a prompt extubation attempt and ventilator-free days among adult patients with acute brain injury. Methods: We performed an emulation of a previously designed randomized controlled trial using data from the Toronto Intensive Care Observational Registry in eight ICUs in Toronto, Ontario, Canada. We included mechanically ventilated adult patients with acute brain injury who had a first successful spontaneous breathing trial. Our main exposure was prompt extubation (i.e., on the same calendar day after the first successful spontaneous breathing trial). The primary outcome was ventilator-free days up to 28 days. We used inverse probability of treatment weighting to adjust for confounding and reported treatment effects using incidence rate ratios and 95% confidence intervals. Measurements and Main Results: A total of 1,406 patients from April 2014 through March 2023 met inclusion criteria. The main reasons for admission were traumatic brain injury (40%), stroke (ischemic or hemorrhagic; 20%), seizures (11%), and subarachnoid hemorrhage (9%). Over half (57%) of patients underwent prompt extubation after their first successful spontaneous breathing trial. Prompt extubation was associated with more ventilator-free days (incidence rate ratio, 1.24; 95% confidence interval, 1.19-1.29) when compared with no prompt extubation. Conclusions: Prompt extubation after a first successful spontaneous breathing trial was associated with more ventilator-free days (up to 28 d) among adults with acute brain injury receiving invasive mechanical ventilation. The original trial protocol was registered with www.clinicaltrials.gov (NCT04291235).

Elucidating the causal relationship of mechanical power and lung injury: a dynamic approach to ventilator management

BACKGROUND

Mechanical power (MP) serves as a crucial predictive indicator for ventilator-induced lung injury and plays a pivotal role in tailoring the management of mechanical ventilation. However, its application across different diseases and stages remains nuanced.

METHODS

Using AmsterdamUMCdb, we conducted a retrospective study to analyze the causal relationship between MP and outcomes of invasive mechanical ventilation, specifically SpO2/FiO2 ratio (P/F) and ventilator-free days at day 28 (VFD28). We employed causal inferential analysis with backdoor linear regression and double machine learning, guided by directed acyclic graphs, to estimate the average treatment effect (ATE) in the whole population and conditional average treatment effect (CATE) in the individual cohort. Additionally, to enhance interpretability and identify MP thresholds, we conducted a simulation analysis.

RESULTS

In the study, we included 11,110 unique admissions into analysis, of which 58.3% (6391) were surgical admissions. We revealed a negative and significant causal effect of median MP on VFD28, with estimated ATEs of -0.135 (95% confidence interval [CI]: -0.15 to -0.121). The similar effect was not observed in Maximal MP and minimal MP. The effect of MP was more pronounced in the medical subgroup, with a CATE of -0.173 (95% CI: -0.197 to -0.143) determined through backdoor linear regression. Patients with cardio, respiratory, and infection diagnoses, who required long-term intubation, sustained higher impact on CATEs across various admission diagnoses. Our simulations showed that there is no single MP threshold that can be applied to all patients, as the optimal threshold varies depending on the patient's condition.

CONCLUSION

Our study underscores the importance of tailoring MP adjustments on an individualized basis in ventilator management. This approach opens up new avenues for personalized treatment strategies and provides fresh insights into the real-time impact of MP in diverse clinical scenarios. It highlights the significance of median MP while acknowledging the absence of universally applicable thresholds.

Applying positive end-expiratory pressure before and during endotracheal tube removal versus extubation with concomitant aspiration: protocol for the randomised controlled multicentre EXSUPEEP trial

INTRODUCTION

The optimal method for removing the endotracheal tube (ETT) during extubation in the intensive care unit (ICU) remains uncertain. Two methods are described for removing the ETT in ICU, namely the 'Traditional technique' with continuous aspiration during cuff deflation and ETT removal; and the 'PEEP' method, which consists in applying positive end-expiratory pressure (PEEP) before and during cuff deflation and ETT removal. Our hypothesis is that applying PEEP during extubation in the ICU would improve clinical outcome.

METHODS AND ANALYSIS

This is a prospective, multicentre, randomised, open-label, controlled, superiority trial, analysed by intention-to-treat, comparing ETT removal with concomitant suction vs application of PEEP before and during ETT removal. In total, 424 patients will be recruited and randomly assigned in a 1:1 ratio to one of two groups, according to the strategy of ETT removal. The primary outcome is the number of days free from any mechanical ventilation within 28 days following extubation. Secondary outcomes include the reintubation rate up to 7 days after ETT removal, the cumulative duration of non-invasive ventilation up to 7 days following extubation, the rate of acute respiratory failure, the rate of acquired pneumonia during the first 7 days following ETT removal, the length of stay in ICU and in hospital and all-cause mortality at 28 days following ETT removal.

ETHICS AND DISSEMINATION

The study was approved by the Ethics Committee 'CPP Ile de France II'. Patients will be included after providing written informed consent. The results will be submitted for publication in peer-reviewed journals, and in national and international congresses.

TRIAL REGISTRATION NUMBER

NCT05147636.

Intubation Versus Tracheotomy Outcomes in Critically Ill COVID-19 Patients in Low-Resource Settings: What Do We Know?

Background: Patients undergoing prolonged mechanical ventilation commonly require tracheotomy. The main aim of this study was to evaluate the outcomes of tracheotomy for patients with acute respiratory distress syndrome (ARDS) associated with COVID-19 in low-resource settings. Methods: A retrospective, single-center, observational cohort study was performed on patients with ARDS associated with COVID-19. Patients who underwent intubation alone were compared with those who received both intubation and subsequent tracheotomy. The analysis included patient demographics, comorbidities, and outcomes. Results: Patients undergoing tracheotomy (n = 89) were compared with intubated patients (n = 622). The median time from intubation to tracheotomy was 10 days (IQR: 6-15 days). Overall, 608 patients (85.5%) died in the hospital. Thirty-seven patients (35.9%) in the survival group had tracheostomy compared with fifty-two patients (8.5%) in the non-survival group (p < 0.001). The Kaplan-Meier curve shows a higher probability of survival in the tracheotomy group compared with the non-tracheotomy group (log-rank test: p < 0.001). Tracheotomy was found to be independently associated with lower in-hospital mortality (HR = 0.16 [95% CI: 0.11-0.23], p < 0.001) in the multivariable Cox proportional hazards regression analysis after adjusting for potential confounding factors. Furthermore, tracheotomy was associated with a higher cumulative incidence of being alive and off the ventilator at day 28 (SHR = 2.87 [95% CI: 1.88-4.38], p < 0.001). Conclusions: Tracheotomy was associated with reduced in-hospital mortality and longer ventilator-free days.

Early Prone Positioning As a Rescue Therapy for Moderate-to-severe Primary Graft Dysfunction After Bilateral Lung Transplant

OBJECTIVES

Primary graft dysfunction (PGD) affects survival after lung transplant (LT). The current hypothesis was that prone positioning (PP), proposed as a rescue maneuver to treat refractory hypoxemia due to PGD, may improve LT outcomes, especially when applied early.

DESIGN

Bilateral LT recipients developing moderate-to-severe PGD within 24 hours from intensive care unit admission were enrolled. From January 2020 to November 2021, patients developing PGD after LT were turned prone between 24 and 48 hours after diagnosis, only in case of radiological or oxygenation worsening ("late PP" group). After November 2021, patients were routinely turned prone within 24 hours from PGD diagnosis ("early PP"). A propensity score-weighted analysis, adjusted for clinically relevant covariates, was applied.

SETTING

Intensive care unit.

PARTICIPANTS

Bilateral LT recipients.

INTERVENTIONS

Early PP, late PP, or supine position.

MEASUREMENTS AND MAIN RESULTS

130 LT patients were screened and 67 were enrolled. A total of 25 (37%) recipients were treated in the supine position, 24 (36%) in early PP, and 18 (27%) in late PP. After propensity score weighting, both supine treatment (estimated effect for 1 ventilator-free day = 8.23, standard error: 2.97, p = 0.007) and early PP treatment (estimated effect = 9.42, standard error: 2.59, p < 0.001) were associated with greater 28-day ventilator-free days than late PP treatment (reference). Compared with late PP, early PP was also associated with better oxygenation, driving pressure, and static respiratory system compliance. Compared with supine recipients, the early PP group showed better oxygenation at 72 hours after PGD diagnosis.

CONCLUSIONS

Early PP in LT recipients with moderate-to-severe PGD seems to be associated with better 28-day ventilator-free days, oxygenation, and driving pressure than late PP.

Lack of diversity in patients undergoing carotid artery stenting: Implications for the Distressed Community Index

INTRODUCTION

As the role of social determinants in carotid artery stenting (CAS) outcomes remains unclear, we investigated the association between the Distressed Community Index (DCI) (zip-code based) and post-CAS mortality/stroke outcomes.

METHODS

We analyzed patients undergoing CAS from 2015 to 2019 using the Medicare claims-linked Vascular Quality Initiative database. Patients were grouped based on high (DCI ⩾ 60) and low (DCI < 60) community distress. We analyzed 36-month mortality using Kaplan-Meier survival curves and hierarchical Cox regression, and 36-month stroke using cumulative incidence function curves and Fine-Gray models.

RESULTS

The final cohort included 8717 patients (3032 DCI ⩾ 60), with a mean DCI score of 46.2 (± 28.5) and mean age of 74.7 (± 7.8) years. Most participants were men (64.3%), White (92.7%), and non-Hispanic/Latino (97.7%). There was no significant difference in the 36-month mortality incidence between high and low community distress groups (25.6% vs 23.5%, p = 0.22), and no significant association between high community distress and mortality (unadjusted HR: 1.04; 95% CI 0.90-1.21; adjusted HR: 1.02; 95% CI 0.89-1.17). The high community distress group experienced an elevated 36-month stroke incidence (26.8% vs 22.4%, p = 0.048), but no significant association with stroke was observed (unadjusted sub-HR: 1.12; 95% CI 1.00-1.24; adjusted sub-HR: 1.03; 95% CI 0.92-1.16).

CONCLUSION

Our cohort showed underrepresentation in terms of sex, race, and ethnicity, with a skewed DCI distribution towards lower community distress. Contrary to what we know about community distress, no independent association between higher community distress and post-CAS stroke/mortality risk was found. Future work must examine whether accessibility barriers and selective CAS allocation explain our results.

Abdominal Hypoperfusion and Acute Kidney Injury in the Critically Ill Patient with Liver Cirrhosis: A Prospective Cohort Study

Background

Reduced abdominal perfusion pressure (APP) is an underdiagnosed potential pathophysiological mechanism for acute kidney injury (AKI) in the patient with liver cirrhosis and ascites. This study aimed to analyze the prevalence of abdominal hypoperfusion (AhP) (APP <60 mm Hg) and the impact of APP on AKI in critically ill patients with liver cirrhosis.

Methods

This was a post hoc analysis from a prospective cohort study set in a general ICU at a tertiary university hospital. Patients were recruited between October 2016 and December 2021. Acute renal failure (ARF) was defined by stage 3 AKI according to the International Club of Ascites.

Results

Fifty-eight patients where included, with a mean age of 57 (±8.4) years, 79% were male, and 93% had acute-on-chronic liver failure at admission. The prevalence of AhP reached 75%, and 29% of cases had persisting AhP during the first week of ICU stay. Patients with baseline AhP had a higher 28-day mortality compared to those without AhP (respectively, 76% vs. 49%, p = 0.03). Acute renal failure developed in 48% of patients. Higher serum urea (aOR: 1.01, 95% CI: 1.00-1.02, p = 0.04) and white blood cell count (aOR: 1.1, 95% CI: 1.01-1.2, p = 0.02) at ICU admission, as well as low persisting APP (aOR: 0.9, 95% CI: 0.86-0.98, p = 0.02) were independent risk factors for ARF.

Conclusion

Critically ill patients with liver cirrhosis presented a high prevalence of ARF, independently associated with higher baseline serum urea and WBC, and lower persisting APP. A structured clinical approach to optimize APP may reduce renal dysfunction in high-risk patients with cirrhosis.

Composite Primary Outcomes Reported in Studies of Critical Care: A Scoping Review

OBJECTIVE

Composite primary outcomes (CPO) (incorporating both mortality and non-mortality outcomes) offer several advantages over mortality as an outcome for critical care research. Our objective was to explore and map the literature to report on CPO evaluated in critical care research.

DATA SOURCES

PubMed, Embase, Cumulative Index to Nursing and Allied Health Literature, Scopus, and Cochrane Library from January 2000 to January 2024.

STUDY SELECTION

All studies (both non-randomized controlled trial [RCT] and RCT) conducted in ICUs treating adult patients (18 yr old or older) that described CPOs and their definitions, were included for mapping, reporting, and analyzing CPOs without any restrictions.

DATA EXTRACTION

Independent double-screening of abstracts/full texts and data extraction was performed using a pilot-tested extraction template. The data collected included characteristics of CPO, definitions, trends, and death handling techniques used while reporting the CPO.

DATA SYNTHESIS

Seventeen CPOs were extracted from 71 studies, predominantly reported in the setting of pharmaceutical studies (48/71, 67.6%), used RCT methodology (60/71, 84.5%), and were mostly single-center studies (55/71, 77.5%). Ventilator-free days were the most commonly reported CPO (29/71, 40.8%) with marked variability in the definition used and death handling (0 d in 33 studies and -1 d in 7 studies). The most common statistical paradigm used was frequentist (63/71, 88.7%) and the study follow-up time was 90 days with 28 studies using this timeline (28/71, 39.4%). Narrative synthesis highlighted the variability in defining CPO.

CONCLUSIONS

CPOs are an emerging set of outcomes increasingly reported in critical care research. There was significant heterogeneity in definitions used, follow-up times, and reporting trends.

Effects of two different dexamethasone dosing regimens on ventilator-free days and long-term mortality in COVID-19 patients with moderate-to-severe ARDS: the REMED randomized clinical trial

BACKGROUND

Dexamethasone 6 mg in patients with severe COVID-19 has been shown to decrease mortality and morbidity. The effects of higher doses of corticosteroid, that would further increase anti-inflammatory effects, are uncertain. The objective of our study was to assess the effect of 20 mg dexamethasone vs. 6 mg dexamethasone intravenously in patients with moderate-to-severe acute respiratory distress syndrome (ARDS) and COVID-19.

METHODS

In a multicenter, open-label, randomized trial conducted in nine hospitals in the Czech Republic, we randomized adult patients with ARDS and COVID-19 requiring high-flow oxygen, noninvasive or invasive mechanical ventilation to receive either intravenous high-dose dexamethasone (20 mg/day on days 1-5, 10 mg/day on days 6-10) or standard-dose dexamethasone (6 mg/d, days 1-10). The primary outcome was 28-day ventilator-free days. The five secondary outcomes were 60-day mortality, C-reactive protein dynamics, 14-day WHO (World Health Organization) Clinical Progression Scale score, adverse events and 90-day Barthel index. The long-term outcomes were 180- and 360-day mortality and the Barthel index. The planned sample size was 300, with interim analysis after enrollment of 150 patients.

RESULTS

The trial was stopped due to a lack of recruitment, and the follow-up was completed in February 2023. Among 234 randomized patients of 300 planned patients, the primary outcome was available for 224 patients (110 high-dose and 114 standard-dose dexamethasone; median [interquartile range (IQR)] age, 59.0 [48.5-66.0] years; 130 [58.0%] were receiving noninvasive or invasive mechanical ventilation at baseline). The mean number of 28-day ventilator-free days was 8.9 (± 11.5) days for high-dose dexamethasone and 8.0 (± 10.7) days for standard-dose dexamethasone, with an absolute difference of + 0.81 days (95% CI - 2.12-3.73 days). None of the prespecified secondary outcomes, including adverse events, differed between the groups.

CONCLUSIONS

Despite not reaching its prespecified enrollment, there was no signal to either benefit or harm high-dose dexamethasone over standard-dose dexamethasone in patients with COVID-19 and moderate-to-severe ARDS. Trial registration Trial registration: ClinicalTrials.gov Identifier: NCT04663555. Registered 10 December 2020, https://clinicaltrials.gov/study/NCT04663555?term=NCT04663555&rank=1 and EudraCT: 2020-005887-70.

Fluid balance neutralization secured by hemodynamic monitoring versus protocolized standard of care in patients with acute circulatory failure requiring continuous renal replacement therapy: results of the GO NEUTRAL randomized controlled trial

PURPOSE

Net ultrafiltration (UFNET) during continuous renal replacement therapy (CRRT) can control fluid balance (FB), but is usually 0 ml·h-1 in patients with vasopressors due to the risk of hemodynamic instability associated with CRRT (HIRRT). We evaluated a UFNET strategy adjusted by functional hemodynamics to control the FB of patients with vasopressors, compared to the standard of care.

METHODS

In this randomized, controlled, open-label, parallel-group, multicenter, proof-of-concept trial, adults receiving vasopressors, CRRT since ≤ 24 h and cardiac output monitoring were randomized (ratio 1:1) to receive during 72 h a UFNET ≥ 100 ml·h-1, adjusted using a functional hemodynamic protocol (intervention), or a UFNET ≤ 25 ml·h-1 (control). The primary outcome was the cumulative FB at 72 h and was analyzed in patients alive at 72 h and in whom monitoring and CRRT were continuously provided (modified intention-to-treat population [mITT]). Secondary outcomes were analyzed in the intention-to-treat (ITT) population.

RESULTS

Between June 2021 and April 2023, 55 patients (age 69 [interquartile range, IQR: 62; 74], 35% female, Sequential Organ Failure Assessment (SOFA) 13 [11; 15]) were randomized (25 interventions, 30 controls). In the mITT population, (21 interventions, 24 controls), the 72 h FB was -2650 [-4574; -309] ml in the intervention arm, and 1841 [821; 5327] ml in controls (difference: 4942 [95% confidence interval: 2736-6902] ml, P < 0.01). Hemodynamics, oxygenation and the number of HIRRT at 72 h, and day-90 mortality did not statistically differ between arms.

CONCLUSION

In patients with vasopressors, a UFNET fluid removal strategy secured by a hemodynamic protocol allowed active fluid balance control, compared to the standard of care.

A comparison of computational algorithms for the Bayesian analysis of clinical trials

BACKGROUND

Clinical trials are increasingly using Bayesian methods for their design and analysis. Inference in Bayesian trials typically uses simulation-based approaches such as Markov Chain Monte Carlo methods. Markov Chain Monte Carlo has high computational cost and can be complex to implement. The Integrated Nested Laplace Approximations algorithm provides approximate Bayesian inference without the need for computationally complex simulations, making it more efficient than Markov Chain Monte Carlo. The practical properties of Integrated Nested Laplace Approximations compared to Markov Chain Monte Carlo have not been considered for clinical trials. Using data from a published clinical trial, we aim to investigate whether Integrated Nested Laplace Approximations is a feasible and accurate alternative to Markov Chain Monte Carlo and provide practical guidance for trialists interested in Bayesian trial design.

METHODS

Data from an international Bayesian multi-platform adaptive trial that compared therapeutic-dose anticoagulation with heparin to usual care in non-critically ill patients hospitalized for COVID-19 were used to fit Bayesian hierarchical generalized mixed models. Integrated Nested Laplace Approximations was compared to two Markov Chain Monte Carlo algorithms, implemented in the software JAGS and stan, using packages available in the statistical software R. Seven outcomes were analysed: organ-support free days (an ordinal outcome), five binary outcomes related to survival and length of hospital stay, and a time-to-event outcome. The posterior distributions for the treatment and sex effects and the variances for the hierarchical effects of age, site and time period were obtained. We summarized these posteriors by calculating the mean, standard deviations and the 95% equitailed credible intervals and presenting the results graphically. The computation time for each algorithm was recorded.

RESULTS

The average overlap of the 95% credible interval for the treatment and sex effects estimated using Integrated Nested Laplace Approximations was 96% and 97.6% compared with stan, respectively. The graphical posterior densities for these effects overlapped for all three algorithms. The posterior mean for the variance of the hierarchical effects of age, site and time estimated using Integrated Nested Laplace Approximations are within the 95% credible interval estimated using Markov Chain Monte Carlo but the average overlap of the credible interval is lower, 77%, 85.6% and 91.3%, respectively, for Integrated Nested Laplace Approximations compared to stan. Integrated Nested Laplace Approximations and stan were easily implemented in clear, well-established packages in R, while JAGS required the direct specification of the model. Integrated Nested Laplace Approximations was between 85 and 269 times faster than stan and 26 and 1852 times faster than JAGS.

CONCLUSION

Integrated Nested Laplace Approximations could reduce the computational complexity of Bayesian analysis in clinical trials as it is easy to implement in R, substantially faster than Markov Chain Monte Carlo methods implemented in JAGS and stan, and provides near identical approximations to the posterior distributions for the treatment effect. Integrated Nested Laplace Approximations was less accurate when estimating the posterior distribution for the variance of hierarchical effects, particularly for the proportional odds model, and future work should determine if the Integrated Nested Laplace Approximations algorithm can be adjusted to improve this estimation.

Severity of Inhalation Injury and Risk of Nosocomial Pneumonia: A Retrospective Cohort Study

BACKGROUND

The impact of inhalation injury on risk of nosocomial pneumonia (NP), an important complication in patients with burns, is not well established.

RESEARCH QUESTION

Is more severe inhalation injury associated with increased risk of NP?

STUDY DESIGN AND METHODS

We performed a retrospective cohort study of patients with suspected inhalation injury admitted to a regional burn center from 2011 to 2022 who underwent diagnostic bronchoscopy within 48 h of admission. We estimated the association of high-grade inhalation injury (Abbreviated Injury Scale grade 3 and 4) vs low-grade inhalation injury (Abbreviated Injury Scale grade 1 and 2) with NP adjusted for age, burn size, and comorbid obstructive lung disease. Death and hospital discharge were considered competing risks.

RESULTS

Of the 245 patients analyzed, 51 (21%) had high-grade injury, 180 (73%) had low-grade injury, and 14 (6%) had no inhalation injury. Among the 236 patients hospitalized for ≥ 48 h, NP occurred in 24 of 50 patients (48%) in the high-grade group, 54 of 172 patients (31%) in the low-grade group, and two of 14 patients (14%) in the no inhalation injury group. High-grade (vs low-grade) inhalation injury was associated with higher hazard of NP in both the proportional cause-specific hazard model (cause-specific hazard ratio, 2.04; 95% CI, 1.26-3.30; P = .004) and Fine-Gray subdistribution hazard model (subdistribution hazard ratio for NP, 2.24; 95% CI, 1.38-3.64; P = .001).

INTERPRETATION

In this study, among patients with inhalation injury, more severe injury was associated with higher hazard of NP in competing risk analysis. Additional research is needed to investigate mechanisms that may explain the relationship between inhalation injury and NP and to identify more effective risk reduction strategies.

A cluster randomized trial on inspiratory effort-targeted pressure support adjustment strategy in patients undergoing assisted mechanical ventilation: protocol for the IT-PSV study

Background

Pressure support ventilation (PSV) is one of the most frequently used ventilator modes in the intensive care unit (ICU). The successful implementation of PSV depends on matching the patient's inspiratory effort with the ventilator support. In clinical practice, the pressure support level is usually set and adjusted according to tidal volume and respiratory rate. However, these parameters may not fully represent the patient's effort. Previous studies have shown that pressure muscle index (PMI), which is measured as the difference between the peak and plateau airway pressure during an end-inspiratory airway occlusion, could reliably determine the low and high inspiratory effort during PSV. Herein we present the study protocol for the Inspiratory effort-Targeted Pressure Support Ventilation (IT-PSV) trial to determine the effect of a PMI-targeted pressure support setting strategy on clinical outcomes in patients undergoing PSV.

Methods and analysis

This is a cluster randomized controlled trial. Sixteen ICUs in academic hospitals will be included, eight of which will be randomly allocated to the PMI-targeted group and eight to the tidal volume/respiratory rate-targeted group. Before the initiation of the study, a four-week comprehensive training program, which includes courses of PSV initiation, pressure support adjustment, and weaning process, will be conducted for all staff in the participating ICUs. Adult patients with acute hypoxic respiratory failure and undergoing PSV within 24 h will be included. Pressure support setting and adjustment will follow the strategy according to the grouping. The primary outcome is the ventilator-free days at 28 days after enrollment. The patients will be followed up until successful weaning or separation of mechanical ventilation, death, hospital discharge, or until 28 days after randomization, whichever comes first.

Discussion

The IT-PSV trial will examine the effect of an inspiratory effort-targeted PSV setting strategy on the duration of mechanical ventilation. If positive, it will provide a new physiological-based PSV management that could potentially facilitate protective assisted ventilation.

Clinical trial registration

ClinicalTrials.gov, identifier NCT06526598.

Comparison of Fixed Dosing vs Train of Four Titration of Cisatracurium in COVID-19 ARDS Patients

Background: Early neuromuscular blockade with cisatracurium has been associated with improved outcomes in moderate-severe acute respiratory distress syndrome (ARDS). Previous studies have demonstrated increased drug utilization without benefits in oxygenation using fixed dose cisatracurium compared to train-of-four (TOF) titration. Objective: We sought to compare a novel, lower fixed dose cisatracurium protocol to TOF titration evaluating the impact on PaO2:FiO2 ratio (P/F). Methods: We conducted a single-center retrospective cohort study comparing fixed dose cisatracurium to TOF titration. We included patients aged 18-89 treated for COVID-19 ARDS with a baseline P/F≤200 who received a cisatracurium infusion for ≥12 h. The primary outcome was change in P/F at 48 h from baseline. Secondary outcomes included change in P/F at 24 h and 7 days, need for mechanical ventilation at day 28, and cisatracurium utilization. Results: Analyses included 125 patients (fixed dose = 65, TOF = 60). Severe ARDS was common with a baseline median P/F of 73.7 vs 79.5, P = .133. The change in P/F at 48 h was larger in the TOF cohort in the adjusted analysis (24.9 vs 70.8, P < .005). The rate and total cumulative dose of cisatracurium were higher in the fixed dose cohort (5 vs 3 mcg/kg/min, P < .001; 1034 vs 612 mg, P < .001) despite similar infusion durations (44.1 h vs 48.5 h, P = .642). Conclusions: Patients in the TOF cisatracurium cohort had improved P/F at 48 h compared to the fixed dose cohort, while also using only 60% of the cumulative dose. Future directions should include analysis of the implications of increased cisatracurium exposure on patient outcomes.

CIRCULATING HEPARAN SULFATE PROFILES IN PEDIATRIC ACUTE RESPIRATORY DISTRESS SYNDROME

ABSTRACT

Introduction: Sepsis-induced degradation of endothelial glycocalyx heparan sulfate (HS) contributes to the pulmonary microvascular endothelial injury characteristic of acute respiratory distress syndrome (ARDS) pathogenesis. Our objectives were to (1) examine relationships between plasma indices of HS degradation and protein biomarkers of endothelial injury and (2) identify patient subgroups characterized by distinct profiles of HS degradation in children with ARDS. Methods: We analyzed prospectively collected plasma (2018-2020) from a cohort of invasively mechanically ventilated children (aged >1 month to <18 years) with ARDS. Mass spectrometry characterized and quantified patterns of HS disaccharide sulfation. Protein biomarkers reflective of endothelial injury (e.g., angiopoietin-2, vascular cell adhesion molecule-1, soluble thrombomodulin) were measured with a multiplex immunoassay. Pearson correlation coefficients were used to construct a biomarker correlation network. Centrality metrics detected influential biomarkers (i.e., network hubs). K-means clustering identified unique patient subgroups based on HS disaccharide profiles. Results: We evaluated 36 patients with pediatric ARDS. HS disaccharide sulfation patterns, 6S, NS, and NS2S, positively correlated with all biomarkers of endothelial injury (all P < 0.05) and were classified as network hubs. We identified three patient subgroups, with cluster 3 (n = 5) demonstrating elevated levels of 6S and N-sulfated HS disaccharides. In cluster 3, 60% of children were female and nonpulmonary sepsis accounted for 60% of cases. Relative to cluster 1 (n = 12), cluster 3 was associated with higher oxygen saturation index (P = 0.029) and fewer 28-day ventilator-free days (P = 0.016). Conclusions: Circulating highly sulfated HS fragments may represent emerging mechanistic biomarkers of endothelial injury and disease severity in pediatric ARDS.

Statistical Power and Performance of Strategies to Analyze Composites of Survival and Duration of Ventilation in Clinical Trials

BACKGROUND

Patients with acute hypoxemic respiratory failure are at high risk of death and prolonged time on the ventilator. Interventions often aim to reduce both mortality and time on the ventilator. Many methods have been proposed for analyzing these endpoints as a single composite outcome (days alive and free of ventilation), but it is unclear which analytical method provides the best performance. Thus, we aimed to determine the analysis method with the highest statistical power for use in clinical trials.

METHODS

Using statistical simulation, we compared multiple methods for analyzing days alive and free of ventilation: the t, Wilcoxon rank-sum, and Kryger Jensen and Lange tests, as well as the proportional odds, hurdle-Poisson, and competing risk models. We compared 14 scenarios relating to: 1) varying baseline distributions of mortality and duration of ventilation, which were based on data from a registry of patients with acute hypoxemic respiratory failure and 2) the varying effects of treatment on mortality and duration of ventilation.

RESULTS AND CONCLUSIONS

All methods have good control of type 1 error rates (i.e., avoid false positive findings). When data are simulated using a proportional odds model, the t test and ordinal models have the highest relative power (92% and 90%, respectively), followed by competing risk models. When the data are simulated using survival models, the competing risk models have the highest power (100% and 92%), followed by the t test and a ten-category ordinal model. All models struggled to detect the effect of the intervention when the treatment only affected one of mortality and duration of ventilation. Overall, the best performing analytical strategy depends on the respective effects of treatment on survival and duration of ventilation and the underlying distribution of the outcomes. The evaluated models each provide a different interpretation for the treatment effect, which must be considered alongside the statistical power when selecting analysis models.

Comparing the impact of targeting limited driving pressure to low tidal volume ventilation on mortality in mechanically ventilated adults with COVID-19 ARDS: an exploratory target trial emulation

BACKGROUND

An association between driving pressure (∆P) and the outcomes of invasive mechanical ventilation (IMV) may exist. However, the effect of a sustained limitation of ∆P on mortality in patients with acute respiratory distress syndrome (ARDS), including patients with COVID-19 (COVID-19-related acute respiratory distress syndrome (C-ARDS)) undergoing IMV, has not been rigorously evaluated. The use of emulations of a target trial in intensive care unit research remains in its infancy. To inform future, large ARDS target trials, we explored using a target trial emulation approach to analyse data from a cohort of IMV adults with C-ARDS to determine whether maintaining daily ∆p<15 cm H2O (in addition to traditional low tidal volume ventilation (LTVV) (tidal volume 5-7 cc/PBW+plateau pressure (Pplat) ≤30 cm H2O), compared with LTVV alone, affects the 28-day mortality.

METHODS

To emulate a target trial, adults with C-ARDS requiring >24 hours of IMV were considered to be assigned to limited ∆P or LTVV. Lung mechanics were measured twice daily after ventilator setting adjustments were made. To evaluate the effect of each lung-protective ventilation (LPV) strategy on the 28-day mortality, we fit a stabilised inverse probability weighted marginal structural model that adjusted for baseline and time-varying confounders known to affect protection strategy use/adherence or survival.

RESULTS

Among the 92 patients included, 27 (29.3%) followed limited ∆P ventilation, 23 (25.0%) the LTVV strategy and 42 (45.7%) received no LPV strategy. The adjusted estimated 28-day survival was 47.0% (95% CI 23%, 76%) in the limited ∆P group, 70.3% in the LTVV group (95% CI 37.6%, 100%) and 37.6% (95% CI 20.8%, 58.0%) in the no LPV strategy group.

INTERPRETATION

Limiting ∆P may not provide additional survival benefits for patients with C-ARDS over LTVV. Our results help inform the development of future target trial emulations focused on evaluating LPV strategies, including reduced ∆P, in adults with ARDS.

Rapid response system for critically ill patients with haematological malignancies: A pre- and post-intervention study

BACKGROUND

This study aimed to determine whether implementing a rapid response system (RRS) is associated with improved short-term outcomes in critically ill patients with haematological malignancies.

METHODS

Our monocentric pre- versus post-intervention study was conducted between January 2012 and April 2020. RRS was activated at early signs of haemodynamic or respiratory failure. The primary outcome was the reduction in Sequential Organ Failure Assessment (SOFA) score on Day 3 after intensive care unit (ICU) admission. Secondary outcomes included time to ICU admission and mortality.

RESULTS

A total of 209 patients with a median age of 59 years were enrolled (108 in the pre-intervention period and 101 in the post-intervention period). 22% of them had received an allogeneic transplant. The post-intervention period was associated with a shorter time to ICU admission (195 vs. 390 min, p < .001), a more frequent favourable trend in SOFA score (57% vs. 42%, adjusted odds ratio, 2.02, 95% confidence interval, 1.09 to 3.76), no significant changes in ICU (22% vs. 26%, p = .48) and 1-year (62% vs. 58%, p = .62) mortality rates.

CONCLUSION

Detection of early organ failure and activation of an RRS was associated with faster ICU admission and lower SOFA scores on Day 3 of admission in critically ill patients with haematological malignancies.

Epidemiology, ventilation management and outcomes of COVID-19 ARDS patients versus patients with ARDS due to pneumonia in the Pre-COVID era

BACKGROUND

Ventilation management may differ between COVID-19 ARDS (COVID-ARDS) patients and patients with pre-COVID ARDS (CLASSIC-ARDS); it is uncertain whether associations of ventilation management with outcomes for CLASSIC-ARDS also exist in COVID-ARDS.

METHODS

Individual patient data analysis of COVID-ARDS and CLASSIC-ARDS patients in six observational studies of ventilation, four in the COVID-19 pandemic and two pre-pandemic. Descriptive statistics were used to compare epidemiology and ventilation characteristics. The primary endpoint were key ventilation parameters; other outcomes included mortality and ventilator-free days and alive (VFD-60) at day 60.

RESULTS

This analysis included 6702 COVID-ARDS patients and 1415 CLASSIC-ARDS patients. COVID-ARDS patients received lower median VT (6.6 [6.0 to 7.4] vs 7.3 [6.4 to 8.5] ml/kg PBW; p < 0.001) and higher median PEEP (12.0 [10.0 to 14.0] vs 8.0 [6.0 to 10.0] cm H2O; p < 0.001), at lower median ΔP (13.0 [10.0 to 15.0] vs 16.0 [IQR 12.0 to 20.0] cm H2O; p < 0.001) and higher median Crs (33.5 [26.6 to 42.1] vs 28.1 [21.6 to 38.4] mL/cm H2O; p < 0.001). Following multivariable adjustment, higher ΔP had an independent association with higher 60-day mortality and less VFD-60 in both groups. Higher PEEP had an association with less VFD-60, but only in COVID-ARDS patients.

CONCLUSIONS

Our findings show important differences in key ventilation parameters and associations thereof with outcomes between COVID-ARDS and CLASSIC-ARDS.

TRIAL REGISTRATION

Clinicaltrials.gov (identifier NCT05650957), December 14, 2022.

Pulmonary herpes simplex virus and cytomegalovirus in patients with acute respiratory distress syndrome related to COVID-19

PURPOSE

Human herpesviruses, particularly cytomegalovirus (CMV) and herpes simplex virus (HSV), frequently reactivate in critically ill patients, including those with acute respiratory distress syndrome (ARDS) related to coronavirus disease 2019 (COVID-19). The clinical interpretation of pulmonary herpesvirus reactivation is challenging and there is ongoing debate about its association with mortality and benefit of antiviral medication. We aimed to quantify the incidence and pathogenicity of pulmonary CMV and HSV reactivations in critically ill COVID-19 patients.

METHODS

Mechanically ventilated COVID-19 patients seropositive for CMV or HSV were included in this observational cohort study. Diagnostic bronchoscopy with bronchoalveolar lavage was performed routinely and analyzed for alveolar viral loads and inflammatory biomarkers. Utilizing joint modeling, we explored the dynamic association between viral load trajectories over time and mortality. We explored alveolar inflammatory biomarker dynamics between reactivated and non-reactivated patients.

RESULTS

Pulmonary reactivation (> 104 copies/ml) of CMV occurred in 6% of CMV-seropositive patients (9/156), and pulmonary reactivation of HSV in 37% of HSV-seropositive patients (63/172). HSV viral load dynamics prior to or without antiviral treatment were associated with increased 90-day mortality (hazard ratio [HR] 1.24, 95% confidence interval [CI] 1.04-1.47). The alveolar concentration of several inflammatory biomarkers increased with HSV reactivation, including interleukin (IL)-6, IL-1β, granulocyte colony stimulating factor (G-CSF), and tumor necrosis factor (TNF).

CONCLUSION

In mechanically ventilated COVID-19 patients, HSV reactivations are common, while CMV reactivations were rare. HSV viral load dynamics prior to or without antiviral treatment are associated with mortality. Alveolar inflammation is elevated after HSV reactivation.

Hierarchical endpoints in critical care: A post-hoc exploratory analysis of the standard versus accelerated initiation of renal-replacement therapy in acute kidney injury and the intensity of continuous renal-replacement therapy in critically ill patients trials

PURPOSE

To perform a post-hoc reanalysis of the Standard versus Accelerated Initiation of Renal-Replacement Therapy in Acute Kidney Injury (STARRT-AKI) and the Intensity of Continuous Renal-Replacement Therapy in Critically Ill Patients (RENAL) trials through hierarchical composite endpoint analysis using win ratio (WR).

MATERIAL AND METHODS

All patients with complete information from the STARRT-AKI (which compared accelerated versus standard approaches for renal replacement therapy - RRT initiation) and RENAL (which compared two different RRT doses in critically ill patients) trials were selected. WR was defined as a hierarchical composite endpoint using 90-day mortality, RRT dependency at 90-days, intensive care unit (ICU) length-of-stay (LOS), and hospital LOS (primary analysis); values above the unit represent a benefit of the intervention for the hierarchical composite endpoint. A secondary analysis replacing LOS by days alive and free of RRT was performed. Stratified analyses were performed according to illness severity score, surgical status, and the presence of sepsis.

RESULTS

The WR analysis produced 2,141,830 pairs for the STARRT-AKI trial and 536,446 pairs for the RENAL trial, respectively. The WR results for STARRT-AKI and RENAL were 1.04 (95% confidence interval [CI] 0.96-1.13; p = 0.33) and 1.02 (95% CI; 0.90-1.15; p = 0.75) for the primary analysis, and 0.88 (95% CI; 0.79-0.99; p = 0.03) and 1.02 (95% CI; 0.87-1.21; p = 0.77) for the secondary analysis, respectively. The stratified analysis of the primary suggested possible benefit of the accelerated-strategy in the STARRT-AKI trial for non-surgical patients with sepsis, while the secondary analysis suggested possible harm of the accelerated-strategy for surgical patients without sepsis. There was no evidence of heterogeneity in treatment effects in stratified analyses in the RENAL trial.

CONCLUSION

WR approach using a hierarchical composite endpoint is feasible for trials in critical care nephrology. The primary re-analyses of the STARRT-AKI and RENAL trials both yielded neutral results; however, there was suggestion of heterogeneity in treatment effect in stratified analyses of the STARRT-AKI trial by surgical status and sepsis. Selection of the endpoints and hierarchical ordering before trial design using the WR approach can have important implications for trial interpretation.

TRIAL REGISTRY

ClinicalTrials.gov number NCT02568722 (STARRT-AKI) and NCT00076219 (RENAL).

Exploration of alive-and-ventilator free days as an outcome measure for clinical trials of Resuscitative interventions

BACKGROUND

Outcome selection is a critically important aspect of clinical trial design. Alive-and-ventilator free days is an outcome measure commonly used in critical care clinical trials, but has not been fully explored in resuscitation science.

METHODS

A simulation study was performed to explore approaches to the definition and analysis of alive-and-ventilator free days in cardiac arrest populations. Data from an in-hospital cardiac arrest observational cohort and from the Pragmatic Airway Resuscitation Trial were used to inform and conduct the simulations and validate approaches to alive-and-ventilator free days measurement and analysis.

FINDINGS

Alive-and-ventilator-free days is a flexible outcome measure in cardiac arrest populations. An approach to alive-and-ventilator free days that assigns -1 days when return of spontaneous circulation is not achieved provides a wider distribution of the outcome and improves statistical power. The optimal approach to the analysis of alive-and-ventilator free days varies based on the expected impact of the intervention under study on rates of return of spontaneous circulation, survival, and ventilator-free survival.

CONCLUSIONS

Alive-and-ventilator free days adds to the armamentarium of clinical trialists in the field of resuscitation science.

Absolute values of regional ventilation-perfusion mismatch in patients with ARDS monitored by electrical impedance tomography and the role of dead space and shunt compensation

BACKGROUND

Assessment of regional ventilation/perfusion (V'/Q) mismatch using electrical impedance tomography (EIT) represents a promising advancement for personalized management of the acute respiratory distress syndrome (ARDS). However, accuracy is still hindered by the need for invasive monitoring to calibrate ventilation and perfusion. Here, we propose a non-invasive correction that uses only EIT data and characterized patients with more pronounced compensation of V'/Q mismatch.

METHODS

We enrolled twenty-one ARDS patients on controlled mechanical ventilation. Cardiac output was measured invasively, and ventilation and perfusion were assessed by EIT. Relative V'/Q maps by EIT were calibrated to absolute values using the minute ventilation to invasive cardiac output (MV/CO) ratio (V'/Q-ABS), left unadjusted (V'/Q-REL), or corrected by MV/CO ratio derived from EIT data (V'/Q-CORR). The ratio between ventilation to dependent regions and perfusion reaching shunted units ( V D ' /QSHUNT) was calculated as an index of more effective hypoxic pulmonary vasoconstriction. The ratio between perfusion to non-dependent regions and ventilation to dead space units (QND/ V DS ' ) was calculated as an index of hypocapnic pneumoconstriction.

RESULTS

Our calibration factor correlated with invasive MV/CO (r = 0.65, p < 0.001), showed good accuracy and no apparent bias. Compared to V'/Q-ABS, V'/Q-REL maps overestimated ventilation (p = 0.013) and perfusion (p = 0.002) to low V'/Q units and underestimated ventilation (p = 0.011) and perfusion (p = 0.008) to high V'/Q units. The heterogeneity of ventilation and perfusion reaching different V'/Q compartments was underestimated. V'/Q-CORR maps eliminated all these differences with V'/Q-ABS (p > 0.05). HigherV D ' / Q SHUNT correlated with higher PaO2/FiO2 (r = 0.49, p = 0.025) and lower shunt fraction (ρ =  - 0.59, p = 0.005). HigherQ ND / V DS ' correlated with lower PEEP (ρ =  - 0.62, p = 0.003) and plateau pressure (ρ =  - 0.59, p = 0.005). Lower values of both indexes were associated with less ventilator-free days (p = 0.05 and p = 0.03, respectively).

CONCLUSIONS

Regional V'/Q maps calibrated with a non-invasive EIT-only method closely approximate the ones obtained with invasive monitoring. Higher efficiency of shunt compensation improves oxygenation while compensation of dead space is less needed at lower airway pressure. Patients with more effective compensation mechanisms could have better outcomes.

Impact of intensive prone position therapy on outcomes in intubated patients with ARDS related to COVID-19

BACKGROUND

Previous retrospective research has shown that maintaining prone positioning (PP) for an average of 40 h is associated with an increase of survival rates in intubated patients with COVID-19-related acute respiratory distress syndrome (ARDS). This study aims to determine whether a cumulative PP duration of more than 32 h during the first 2 days of intensive care unit (ICU) admission is associated with increased survival compared to a cumulative PP duration of 32 h or less.

METHODS

This study is an ancillary analysis from a previous large international observational study involving intubated patients placed in PP in the first 48 h of ICU admission in 149 ICUs across France, Belgium and Switzerland. Given that PP is recommended for a 16-h daily duration, intensive PP was defined as a cumulated duration of more than 32 h during the first 48 h, whereas standard PP was defined as a duration equal to or less than 32 h. Patients were followed-up for 90 days. The primary outcome was mortality at day 60. An Inverse Probability Censoring Weighting (IPCW) Cox model including a target emulation trial method was used to analyze the data.

RESULTS

Out of 2137 intubated patients, 753 were placed in PP during the first 48 h of ICU admission. The intensive PP group (n = 79) had a median PP duration of 36 h, while standard PP group (n = 674) had a median of 16 h during the first 48 h. Sixty-day mortality rate in the intensive PP group was 39.2% compared to 38.7% in the standard PP group (p = 0.93). Twenty-eight-day and 90-day mortality as well as the ventilator-free days until day 28 were similar in both groups. After IPCW, there was no significant difference in mortality at day 60 between the two-study groups (HR 0.95 [0.52-1.74], p = 0.87 and HR 1.1 [0.77-1.57], p = 0.61 in complete case analysis or in multiple imputation analysis, respectively).

CONCLUSIONS

This secondary analysis of a large multicenter European cohort of intubated patients with ARDS due to COVID-19 found that intensive PP during the first 48 h did not provide a survival benefit compared to standard PP.

Occurrence of pendelluft during ventilator weaning with T piece correlated with increased mortality in difficult-to-wean patients

BACKGROUND

Difficult-to-wean patients, typically identified as those failing the initial spontaneous breathing trial (SBT), face elevated mortality rates. Pendelluft, frequently observed in patients experiencing SBT failure, can be conveniently detected through bedside monitoring with electrical impedance tomography (EIT). This study aimed to explore the impact of pendelluft during SBT on difficult-to-wean patients.

METHODS

This retrospective observational study included difficult-to-wean patients undergoing spontaneous T piece breathing, during which EIT data were collected. Pendelluft occurrence was defined when its amplitude exceeded 2.5% of global tidal impedance variation. Physiological parameters during SBT were retrospectively retrieved from the EIT Examination Report Form. Other clinical data including mechanical ventilation duration, length of ICU stay, length of hospital stay, and 28-day mortality were retrieved from patient records in the hospital information system for each subject.

RESULTS

Pendelluft was observed in 72 (70.4%) of the 108 included patients, with 16 (14.8%) experiencing mortality by day 28. The pendelluft group exhibited significantly higher mortality (19.7% vs. 3.1%, p = 0.035), longer median mechanical ventilation duration [9 (5-15) vs. 7 (5-11) days, p = 0.041] and shorter ventilator-free days at day 28 [18 (4-22) vs. 20 (16-23) days, p = 0.043]. The presence of pendellfut was independently associated with increased mortality at day 28 (OR = 10.50, 95% confidence interval   1.21-90.99, p = 0.033).

CONCLUSIONS

Pendelluft occurred in 70.4% of difficult-to-wean patients undergoing T piece spontaneous breathing. Pendelluft was associated with worse clinical outcomes, including prolonged mechanical ventilation and increased mortality in this population. Our findings underscore the significance of monitoring pendelluft using EIT during SBT for difficult-to-wean patients.

Measuring Quality-weighted Hospital-Free Days in Acute Respiratory Failure: A Modified Delphi Study

Rationale: Hospital-free days (HFDs), a measure of the number of days alive spent outside the hospital, is increasingly used as an endpoint in studies of patients with acute respiratory failure (ARF) or other critical and serious illnesses. Current approaches to measuring HFDs do not account for decrements in functional status or quality of life that ARF survivors and family members value. Objectives: To develop an acceptable approach to measure quality-weighted HFDs using patient-reported outcomes. Methods: We conducted a four-round modified Delphi process among ARF experts: those with lived or professional experience. Experts rated survivorship domains, instrument and data collection characteristics, and methods to translate responses into quality-weighted HFDs. The consensus threshold was that ⩾70% of respondents rated an item "totally acceptable" or "acceptable" and ⩽15% of respondents rated the item "totally unacceptable," "unacceptable," or "slightly unacceptable." Results: Fifty-seven experts participated in round 1. Response rates were 82-93% for subsequent rounds. Priority survivorship domains were physical function and health-related quality of life. Participants reached a consensus that data collection during ARF recovery should take less than 15 minutes per assessment, allow surrogate completion when patients are unable, and continue for at least 24 months of follow-up. Using the EuroQol-5 Dimensions (EQ-5D) questionnaire to quality weight HFDs met consensus criteria for acceptability. A majority of panelists preferred quality-weighted HFDs to unweighted HFDs or survival for use in future ARF studies. Conclusions: Quality-weighting HFDs using patient and/or surrogate responses to the EQ-5D captured stakeholder priorities and was acceptable to this Delphi panel.

Novel Oxygenation and Saturation Indices for Mortality Prediction in COVID-19 ARDS Patients: The Impact of Driving Pressure and Mechanical Power

Background: The oxygenation index (OI) and oxygen saturation index (OSI) are proven mortality predictors in pediatric and adult patients, traditionally using mean airway pressure (Pmean). We introduce novel indices, replacing Pmean with DP (ΔPinsp), MPdyn, and MPtot, assessing their potential for predicting COVID-19 acute respiratory distress syndrome (ARDS) mortality, comparing them to traditional indices. Methods: We studied 361 adult COVID-19 ARDS patients for 7 days, collecting ΔPinsp, MPdyn, and MPtot, OI-ΔPinsp, OI-MPdyn, OI-MPtot, OSI-ΔPinsp, OSI-MPdyn, and OSI-MPtot. We compared these in surviving and non-surviving patients over the first 7 intensive care unit (ICU) days using Mann-Whitney U test. Logistic regression receiver operating characteristic (ROC) analysis assessed AUC and CI values for ICU mortality on day three. We determined cut-off values using Youden's method and conducted multivariate Cox regression on parameter limits. Results: All indices showed significant differences between surviving and non-surviving patients on the third day of ICU care. The AUC values of OI-ΔPinsp were significantly higher than those of P/F and OI-Pmean (P values .0002 and <.0001, respectively). Similarly, AUC and CI values of OSI-ΔPinsp and OSI-MPdyn were significantly higher than those of SpO2/FiO2 and OSI-Pmean values (OSI-ΔPinsp: P < .0001, OSI-MPdyn: P values .047 and .028, respectively). OI-ΔPinsp, OSI-ΔPinsp, OI-MPdyn, OSI-MPdyn, OI-MPtot, and OSI-MPtot had AUC values of 0.72, 0.71, 0.69, 0.68, 0.66, and 0.64, respectively, with cut-off values associated with hazard ratios and P values of 7.06 (HR = 1.84, P = .002), 8.04 (HR = 2.00, P ≤ .0001), 7.12 (HR = 1.68, P = .001), 5.76 (HR = 1.70, P ≤ .0001), 10.43 (HR = 1.52, P = .006), and 10.68 (HR = 1.66, P = .001), respectively. Conclusions: Critical values of all indices were associated to higher ICU mortality rates and extended mechanical ventilation durations. The OI-ΔPinsp, OSI-ΔPinsp, and OSI-MPdyn indices displayed the strongest predictive capabilities for ICU mortality. These novel indices offer valuable insights for intensivists in the clinical management and decision-making process for ARDS patients.

HAPTOGLOBIN DEPLETION DURING THE FIRST 7 DAYS OF VENO-VENOUS EXTRACORPOREAL MEMBRANE OXYGENATION THERAPY IS ASSOCIATED WITH INCREASED MORTALITY AND ADVERSE OUTCOMES IN PATIENTS WITH ACUTE RESPIRATORY DISTRESS SYNDROME

ABSTRACT

Background: Hemolysis is a frequent complication in patients with sepsis, ARDS, or extracorporeal membrane oxygenation (ECMO). Haptoglobin (Hp) can scavenge released cell-free hemoglobin (CFH). Hemolysis and low plasma concentrations of Hp may be independently associated with mortality in critically ill patients. Methods: This study used a retrospective analysis of 435 patients with ARDS and veno-venous ECMO therapy, admitted to a tertiary ARDS referral center (01/2007-12/2018). Hp depletion was defined as decrease in plasma Hp concentration <0.39 g/L within the first week after ECMO initiation. Patients with Hp depletion were compared to patients without Hp depletion. The primary endpoint was 28-day mortality. Secondary endpoints included organ dysfunction-free, renal replacement therapy-free, vasopressor-free, and ECMO-free composites. Results: Patients with Hp depletion (n = 269) had a significantly higher mortality 28 days after ECMO initiation compared to patients without Hp depletion (43.5% [95% CI 37.52-49.66] vs. 25.3% [19.03-32.74], P < 0.001). Furthermore, patients with Hp depletion had fewer organ dysfunction-free days (subdistribution hazard ratio [SHR] 0.35 [95% CI 0.25-0.50], P < 0.001), lower chances for successful weaning from renal replacement therapy (SHR 0.50 [0.32-0.79], P < 0.001), vasopressor therapy (SHR 0.39 [0.28-0.54], P < 0.001), and ECMO therapy (SHR 0.41 [0.30-0.57], P < 0.001) within 28 days after ECMO initiation. Patients with initial Hp <0.66 g/L had higher risks for Hp depletion than patients with initial Hp ≥0.66 g/L. Conclusion: Patients with Hp depletion within the first week of ECMO therapy might benefit from close monitoring of hemolysis with early detection and elimination of the underlying cause. They might be potential candidates for future Hp supplementation therapy to prevent overload of the CFH-scavenger system.

Medical Complexity, Language Use, and Outcomes in the Pediatric ICU

OBJECTIVES

To determine whether use of a language other than English (LOE) would be associated with medical complexity, and whether medical complexity and LOE together would be associated with worse clinical outcomes.

METHODS

The primary outcome of this single-site retrospective cohort study of PICU encounters from September 1, 2017, through August 31, 2022 was an association between LOE and medical complexity. Univariable and multivariable analyses were performed between demographic factors and medical complexity, both for unique patients and for all encounters. We investigated outcomes of initial illness severity (using Pediatric Logistic Organ Dysfunction-2), length of stay (LOS), days without mechanical ventilation or organ dysfunction using a mixed effects regression model, controlling for age, sex, race and ethnicity, and insurance status.

RESULTS

There were 6802 patients and 10 011 encounters. In multivariable analysis for all encounters, Spanish use (adjusted odds ratio [aOR], 1.29; 95% confidence interval [CI], 1.11-1.49) and language other than English or Spanish (LOES) (aOR, 1.36; 95% CI, 1.02-1.80) were associated with medical complexity. Among unique patients, there remained an association between use of Spanish and medical complexity in multivariable analysis (aOR, 1.26; 95% CI, 1.05-1.52) but not between LOES and medical complexity (aOR, 1.30; 95% CI, 0.92-1.83). Children with medical complexity (CMC) who used an LOES had fewer organ dysfunction-free days (P = .003), PICU LOS was 1.53 times longer (P = .01), and hospital LOS was 1.45 times longer (P = .01) compared with CMC who used English.

CONCLUSIONS

Use of an LOE was independently associated with medical complexity. CMC who used an LOES had a longer LOS.

Tackling Brain and Muscle Dysfunction in Acute Respiratory Distress Syndrome Survivors: NHLBI Workshop Report

Acute respiratory distress syndrome (ARDS) is associated with long-term impairments in brain and muscle function that significantly impact the quality of life of those who survive the acute illness. The mechanisms underlying these impairments are not yet well understood, and evidence-based interventions to minimize the burden on patients remain unproved. The NHLBI of the NIH assembled a workshop in April 2023 to review the state of the science regarding ARDS-associated brain and muscle dysfunction, to identify gaps in current knowledge, and to determine priorities for future investigation. The workshop included presentations by scientific leaders across the translational science spectrum and was open to the public as well as the scientific community. This report describes the themes discussed at the workshop as well as recommendations to advance the field toward the goal of improving the health and well-being of ARDS survivors.

Composite outcome measures in high-impact critical care randomised controlled trials: a systematic review

BACKGROUND

The use of composite outcome measures (COM) in clinical trials is increasing. Whilst their use is associated with benefits, several limitations have been highlighted and there is limited literature exploring their use within critical care. The primary aim of this study was to evaluate the use of COM in high-impact critical care trials, and compare study parameters (including sample size, statistical significance, and consistency of effect estimates) in trials using composite versus non-composite outcomes.

METHODS

A systematic review of 16 high-impact journals was conducted. Randomised controlled trials published between 2012 and 2022 reporting a patient important outcome and involving critical care patients, were included.

RESULTS

8271 trials were screened, and 194 included. 39.1% of all trials used a COM and this increased over time. Of those using a COM, only 52.6% explicitly described the outcome as composite. The median number of components was 2 (IQR 2-3). Trials using a COM recruited fewer participants (409 (198.8-851.5) vs 584 (300-1566, p = 0.004), and their use was not associated with increased rates of statistical significance (19.7% vs 17.8%, p = 0.380). Predicted effect sizes were overestimated in all but 6 trials. For studies using a COM the effect estimates were consistent across all components in 43.4% of trials. 93% of COM included components that were not patient important.

CONCLUSIONS

COM are increasingly used in critical care trials; however effect estimates are frequently inconsistent across COM components confounding outcome interpretations. The use of COM was associated with smaller sample sizes, and no increased likelihood of statistically significant results. Many of the limitations inherent to the use of COM are relevant to critical care research.

Alternative approaches to analyzing ventilator-free days, mortality and duration of ventilation in critical care research

OBJECTIVE

To discuss the strengths and limitations of ventilator-free days and to provide a comprehensive discussion of the different analytic methods for analyzing and interpreting this outcome.

METHODS

Using simulations, the power of different analytical methods was assessed, namely: quantile (median) regression, cumulative logistic regression, generalized pairwise comparison, conditional approach and truncated approach. Overall, 3,000 simulations of a two-arm trial with n = 300 per arm were computed using a two-sided alternative hypothesis and a type I error rate of α = 0.05.

RESULTS

When considering power, median regression did not perform well in studies where the treatment effect was mainly driven by mortality. Median regression performed better in situations with a weak effect on mortality but a strong effect on duration, duration only, and moderate mortality and duration. Cumulative logistic regression was found to produce similar power to the Wilcoxon rank-sum test across all scenarios, being the best strategy for the scenarios of moderate mortality and duration, weak mortality and strong duration, and duration only.

CONCLUSION

In this study, we describe the relative power of new methods for analyzing ventilator-free days in critical care research. Our data provide validation and guidance for the use of the cumulative logistic model, median regression, generalized pairwise comparisons, and the conditional and truncated approach in specific scenarios.

Case volume and specialization in critically ill emergency patients: a nationwide cohort study in Japanese ICUs

BACKGROUND

Previous studies have explored the association between the number of cases and patient outcomes for critical illnesses such as sepsis and trauma, as well as various surgeries, with the expectation that a higher number of cases would have a more favorable effect on patient outcomes. The aim of this study was to elucidate the association among intensive care unit (ICU) case volume, specialization, and patient outcomes in critically ill emergency patients and to determine how ICU case volumes and specializations impact the outcomes of these patients in Japanese ICUs.

METHODS

Utilizing data from the Japanese Intensive Care PAtient Database (JIPAD) from April 2015 to March 2021, this retrospective cohort study was conducted in 80 ICUs across Japan and included 72,214 emergency patients aged ≥ 16 years. The primary outcome measure was in-hospital mortality, and the secondary outcomes encompassed ICU mortality, 28-day mortality, ventilator-free days, and the lengths of ICU and hospital stays. Bayesian hierarchical generalized linear mixed models were used to adjust for patient- and ICU-level variables.

RESULTS

This study revealed a significant association between a higher ICU case volume and decreased in-hospital mortality. In particular, ICUs with a higher percentage (> 75%) of emergency patients showed more pronounced effects, with the odds ratios for in-hospital mortality in the higher case volume quartiles (Q2, Q3, and Q4) being 0.92 (95% credible interval [CI]: 0.88-0.96), 0.70 (95% CI: 0.67-0.73), and 0.78 (95% CI: 0.73-0.83), respectively, compared with the lowest quartile (Q1). Similar trends were observed for various secondary outcomes.

CONCLUSIONS

Higher ICU case volumes were significantly associated with lower in-hospital mortality rates in Japanese ICUs predominantly treating critically ill emergency patients. These findings emphasize the importance of ICU specialization and highlight the potential benefits of centralized care for critically ill emergency patients. These findings are potential insights for improving health care policy in Japan and may be valuable in emergency care settings in other countries with similar healthcare systems, after careful consideration of contextual differences.

Early goal enteral nutrition associated with decreased in-hospital death in mechanically ventilated critically ill adults: a retrospective cohort study

INTRODUCTION

Early enteral nutrition (EN) in critically ill adult patients is thought to improve mortality and morbidity; expert guidelines recommend early initiation of EN in critically ill adults. However, the ideal schedule and dose of EN remain understudied.

STUDY OBJECTIVE

Our objective was to evaluate the relationship between achieving 70% of recommended EN within 2 days of intubation ('early goal EN') and clinical outcomes in mechanically ventilated medically critically ill adults. We hypothesised that early goal EN would be associated with reduced in-hospital death.

METHODS

We conducted a retrospective cohort study of mechanically ventilated adult patients admitted to our medical intensive care unit during 2013-2019. We assessed the proportion of recommended total EN provided to the patient each day following intubation until extubation, death or 7 days whichever was shortest. Patients who received 70% or more of their recommended total daily EN within 2 days of intubation (ie, 'baseline period') were considered to have achieved 'early goal EN'; these patients were compared with patients who did not ('low EN'). The primary outcome was in-hospital death; secondary outcomes were successful extubation and discharge alive.

RESULTS

938 patients met eligibility criteria and survived the baseline period. During the 7-day postintubation period, 64% of all patients reached 70% of recommended daily calories; 33% of patients achieved early goal EN. In unadjusted and adjusted models, early goal EN versus low EN was associated with a lower incidence of in-hospital death (subdistribution HR (SHR) unadjusted=0.63, p=0.0003, SHR adjusted=0.73, p=0.02). Early goal EN was also associated with a higher incidence of successful extubation (SHR unadjusted=1.41, p<0.00001, SHR adjusted=1.27, p=0.002) and discharge alive (SHR unadjusted=1.54, p<0.00001, SHR adjusted=1.24, p=0.02).

CONCLUSIONS

Early goal EN was associated with significant improvement in clinical metrics of decreased in-hospital death, increased extubation and increased hospital discharge alive.

Evaluation of pre-hospital cannabis exposure and hospital opioid utilization in a trauma population: A retrospective cohort

PURPOSE

Cannabis utilization has increased over time for recreational and medical purposes due to its legalization or decriminalization. The effects of cannabis use on opioid utilization are not well understood. The primary objective was to evaluate the total opioid utilization, measured in morphine milligram equivalents (MME), in hospitalized trauma patients that tested positive for tetrahydrocannabinol (THC) on a urine drug screen (UDS).

METHODS

This was a retrospective, cohort study in a level 1 trauma center between 10/17/17 and 12/31/19. Adult trauma patients (aged 15 years and older) who had a UDS completed within 48 h of hospital arrival were eligible for inclusion. Patients were excluded for a hospitalization >14 days, death within 24 h, severe alcohol withdrawal, prescribed cannabinoids, high daily opioid use prior-to-arrival, or transitioned to hospice or palliative care. Group assignments were determined based on the presence or absence of THC on the UDS.

RESULTS

The analysis included 750 patients with 160 (21 %) THC positive patients. The population were primarily male (64.6 %), median age of 56 years [IQR 35-72], with blunt (93 %) injuries from motor vehicle crash or falls (79 %). The THC group was more likely to have other substances present, including amphetamines, benzodiazepines, opiates, and cocaine. The THC group had a higher median injury severity score (10 [IQR 5-17] vs. 9 [5-14], p = 0.0056), and maximum abbreviated injury score (3 [IQR 2-3] vs. 2 [IQR 2-3], p = 0.0009). The THC group had a total higher median opioid utilization during the hospitalization (155 [IQR 68-367] vs. 62 [IQR 13-175] MME; p < 0.0001), which included higher opioid use in the emergency department, floor, and intensive care unit. There were no significant differences in secondary outcomes except the THC group was more likely to receive an opioid prescription at discharge and more likely to require mechanical ventilation. Based on multivariable regression analyses, other variables were associated with increased opioid utilization.

CONCLUSION

Pre-existing THC exposure may be associated with an increased hospital opioid utilization in a trauma population. However, other variables may also play a role in opioid utilization.

Ceftriaxone to prevent early ventilator-associated pneumonia in patients with acute brain injury: a multicentre, randomised, double-blind, placebo-controlled, assessor-masked superiority trial

BACKGROUND

Patients with acute brain injury are at high risk of ventilator-associated pneumonia (VAP). The benefit of short-term antibiotic prophylaxis remains debated. We aimed to establish the effect of an early, single dose of the antibiotic ceftriaxone on the incidence of early VAP in patients with severe brain injury who required mechanical ventilation.

METHODS

PROPHY-VAP was a multicentre, randomised, double-blind, placebo-controlled, assessor-masked, superiority trial conducted in nine intensive care units in eight French university hospitals. We randomly assigned comatose (Glasgow Coma Scale score [GCS] ≤12) adult patients (age ≥18 years) who required mechanical ventilation for at least 48 h after acute brain injury to receive intravenous ceftriaxone 2 g or placebo once within the 12 h following tracheal intubation. Participants did not receive selective oropharyngeal and digestive tract decontamination. The primary outcome was the proportion of patients developing early VAP from the 2nd to the 7th day of mechanical ventilation, confirmed by masked assessors. The analysis was reported in the modified intention-to-treat population, which comprised all randomly assigned patients except those who withdrew or did not give consent to continue and those who did not receive the allocated treatment because they met a criterion for non-eligibility. The trial is registered with ClinicalTrials.gov, NCT02265406.

FINDINGS

From Oct 14, 2015, to May 27, 2020, 345 patients were randomly assigned (1:1) to receive ceftriaxone (n=171) or placebo (n=174); 330 received the allocated intervention and 319 were included in the analysis (162 in the ceftriaxone group and 157 in the placebo group). 166 (52%) participants in the analysis were men and 153 (48%) were women. 15 patients did not receive the allocated intervention after randomisation and 11 withdrew their consent. Adjudication confirmed 93 cases of VAP, including 74 early infections. The incidence of early VAP was lower in the ceftriaxone group than in the placebo group (23 [14%] vs 51 [32%]; hazard ratio 0·60 [95% CI 0·38-0·95], p=0·030), with no microbiological impact and no adverse effects attributable to ceftriaxone.

INTERPRETATION

In patients with acute brain injury, a single ceftriaxone dose decreased the risk of early VAP. On the basis of our findings, we recommend that an early, single dose of ceftriaxone be included in all bundles for the prevention of VAP in patients with brain injury who require mechanical ventilation.

FUNDING

French Ministry of Social Affairs and Health.

The effect of immunosuppressive therapies on the endothelial host response in critically ill COVID-19 patients

While several effective therapies for critically ill patients with COVID-19 have been identified in large, well-conducted trials, the mechanisms underlying these therapies have not been investigated in depth. Our aim is to investigate the association between various immunosuppressive therapies (corticosteroids, tocilizumab and anakinra) and the change in endothelial host response over time in critically ill COVID-19 patients. We conducted a pre-specified multicenter post-hoc analysis in a Dutch cohort of COVID-19 patients admitted to the ICU between March 2020 and September 2021 due to hypoxemic respiratory failure. A panel of 18 immune response biomarkers in the complement, coagulation and endothelial function domains were measured using ELISA or Luminex. Biomarkers were measured on day 0-1, day 2-4 and day 6-8 after start of COVID-19 treatment. Patients were categorized into four treatment groups: no immunomodulatory treatment, corticosteroids, anakinra plus corticosteroids, or tocilizumab plus corticosteroids. The association between treatment group and the change in concentrations of biomarkers was estimated with linear mixed-effects models, using no immunomodulatory treatment as reference group. 109 patients with a median age of 62 years [IQR 54-70] of whom 72% (n = 78) was male, were included in this analysis. Both anakinra plus corticosteroids (n = 22) and tocilizumab plus corticosteroids (n = 38) were associated with an increase in angiopoietin-1 compared to no immune modulator (n = 23) (beta of 0.033 [0.002-0.064] and 0.041 [0.013-0.070] per day, respectively). These treatments, as well as corticosteroids alone (n = 26), were further associated with a decrease in the ratio of angiopoietin-2/angiopoietin-1 (beta of 0.071 [0.034-0.107], 0.060 [0.030-0.091] and 0.043 [0.001-0.085] per day, respectively). Anakinra plus corticosteroids and tocilizumab plus corticosteroids were associated with a decrease in concentrations of complement complex 5b-9 compared to no immunomodulatory treatment (0.038 [0.006-0.071] and 0.023 [0.000-0.047], respectively). Currently established treatments for critically ill COVID-19 patients are associated with a change in biomarkers of the angiopoietin and complement pathways, possibly indicating a role for stability of the endothelium. These results increase the understanding of the mechanisms of interventions and are possibly useful for stratification of patients with other inflammatory conditions which may potentially benefit from these treatments.