Personalized mechanical ventilation guided by ultrasound in patients with acute respiratory distress syndrome (PEGASUS): study protocol for an international randomized clinical trial

BACKGROUND

Acute respiratory distress syndrome (ARDS) is a frequent cause of hypoxemic respiratory failure with a mortality rate of approximately 30%. Identifying ARDS subphenotypes based on "focal" or "non-focal" lung morphology has the potential to better target mechanical ventilation strategies of individual patients. However, classifying morphology through chest radiography or computed tomography is either inaccurate or impractical. Lung ultrasound (LUS) is a non-invasive bedside tool that can accurately distinguish "focal" from "non-focal" lung morphology. We hypothesize that LUS-guided personalized mechanical ventilation in ARDS patients leads to a reduction in 90-day mortality compared to conventional mechanical ventilation.

METHODS

The Personalized Mechanical Ventilation Guided by UltraSound in Patients with Acute Respiratory Distress Syndrome (PEGASUS) study is an investigator-initiated, international, randomized clinical trial (RCT) that plans to enroll 538 invasively ventilated adult intensive care unit (ICU) patients with moderate to severe ARDS. Eligible patients will receive a LUS exam to classify lung morphology as "focal" or "non-focal". Thereafter, patients will be randomized within 12 h after ARDS diagnosis to receive standard care or personalized ventilation where the ventilation strategy is adjusted to the morphology subphenotype, i.e., higher positive end-expiratory pressure (PEEP) and recruitment maneuvers for "non-focal" ARDS and lower PEEP and prone positioning for "focal" ARDS. The primary endpoint is all-cause mortality at day 90. Secondary outcomes are mortality at day 28, ventilator-free days at day 28, ICU length of stay, ICU mortality, hospital length of stay, hospital mortality, and number of complications (ventilator-associated pneumonia, pneumothorax, and need for rescue therapy). After a pilot phase of 80 patients, the correct interpretation of LUS images and correct application of the intervention within the safe limits of mechanical ventilation will be evaluated.

DISCUSSION

PEGASUS is the first RCT that compares LUS-guided personalized mechanical ventilation with conventional ventilation in invasively ventilated patients with moderate and severe ARDS. If this study demonstrates that personalized ventilation guided by LUS can improve the outcomes of ARDS patients, it has the potential to shift the existing one-size-fits-all ventilation strategy towards a more individualized approach.

TRIAL REGISTRATION

The PEGASUS trial was registered before the inclusion of the first patient, https://clinicaltrials.gov/ (ID: NCT05492344).

Existing Data Sources in Clinical Epidemiology: Database of Community Acquired Infections Requiring Hospital Referral in Eastern Denmark (DCAIED) 2018-2021

Infectious diseases are major health care challenges globally and a prevalent cause of admission to emergency departments. Epidemiologic characteristics and outcomes based on population level data are limited. The Database of Community Acquired Infections in Eastern Denmark (DCAIED) 2018-2021 was established with the aim to explore and estimate the population characteristics, and outcomes of patients suffering from community acquired infections at the emergency departments in the Capital Region and the Zealand Region of Denmark using data from electronic medical records. Adult patients (≥18 years) presenting to the emergency department with suspected or confirmed infection are included in the cohort. Presence of sepsis and organ failure are assessed using modified criteria from the Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3). During the inclusion period from January 2018 to January 2022, 2,241,652 adult emergency department visits have been registered. Of these, 451,825 were unique encounters of which 60,316 fulfilled criteria of suspected infection and 28,472 fulfilled sepsis criteria and 8,027 were defined as septic shock. The database covers the entire Capital and Zealand Region of Denmark with an uptake area of 2.6 million inhabitants and includes demographic, laboratory and outcome indicators, with complete follow-up. The database is well-suited for epidemiological research for future national and international collaborations.

Inhalation devices and inhaled corticosteroids particle size influence on severe pneumonia in patients with chronic obstructive pulmonary disease: a nationwide cohort study

BACKGROUND

Inhaled corticosteroids (ICSs) are associated with an increased risk of pneumonia among patients with chronic obstructive pulmonary disease (COPD). The introduction of extrafine particle ICS has aimed to improve the distribution of medicine in the airways by altering deposition within the lungs, potentially affecting efficacy and side effects. It remains unclear if extrafine particle ICS administration alters the risk of pneumonia compared with standard particle size ICS.

METHODS

An observational cohort study including all Danish COPD outpatients receiving ICS from 2010 to 2017. The primary outcome was pneumonia hospitalisation in the different ICS particle dosing regimens. The primary analysis was an adjusted Cox proportional hazards model. For sensitivity analysis, a subgroup analysis of patients receiving spray devices was done. Further, we created a propensity score matched cohort, in which we matched for the same covariates as adjusted for in the main analysis.

RESULTS

A total of 35 691 patients were included of whom 1471 received extrafine particle ICS. Among these patients, 4657 were hospitalised due to pneumonia. Patients with COPD receiving extrafine particle ICS had a lower risk of hospitalisation due to pneumonia compared with patients receiving standard particle size ICS in our primary analysis (HR 0.75; 95% CI 0.63 to 0.89; p=0.002), subgroup analysis (HR 0.54; 95% CI 0.45 to 0.65; p<0.0001) and the propensity-matched population (HR 0.72; 95% CI 0.60 to 0.87; p=0.0006).

INTERPRETATION

The use of extrafine particle ICS administration was associated with a lower risk of pneumonia hospitalisation in patients with COPD compared with those who received standard size treatment.

Early biomarker-guided prediction of bloodstream infection in critically ill patients: C-reactive protein, procalcitonin and leukocytes

Background

Bloodstream infections (BSIs) often lead to critical illness and death. The primary aim of this study was to determine the diagnostic accuracy of the biomarkers C-reactive protein (CRP), procalcitonin (PCT), and leukocyte count for the diagnosis of BSI in critically ill patients.

Methods

This was a nested case–control study based on the Procalcitonin And Survival Study (PASS) trial (n = 1200). Patients who were admitted to the intensive care unit (ICU) <24 hours, and not expected to die within <24 hours, were recruited. For the current study, we included patients with a BSI within ±3 days of ICU admission and matched controls without a BSI in a 1:2 ratio. Diagnostic accuracy for BSI for the biomarkers on days 1, 2, and 3 of ICU admission was assessed. Sensitivity, specificity, and negative and positive predictive values were calculated for prespecified thresholds and for a data-driven cutoff.

Results

In total, there were 525 patients (n = 175 cases, 350 controls). The fixed low threshold for all 3 biomarkers (CRP = 20 mg/L; leucocytes = 10 × 10⁹/L; PCT = 0.4 ng/mL) resulted in negative predictive values on day 1: CRP = 0.91; 95% CI, 0.75–1.00; leukocyte = 0.75; 95% CI, 0.68–0.81; PCT = 0.91; 95% CI, 0.84–0.96). Combining the 3 biomarkers yielded similar results as PCT alone (P = .5).

Conclusions

CRP and PCT could in most cases rule out BSI in critically ill patients. As almost no patients had low CRP and ∼20% had low PCT, a low PCT could be used, along with other information, to guide clinical decisions.

Loop diuretics in adult intensive care patients with fluid overload: a systematic review of randomised clinical trials with meta-analysis and trial sequential analysis

BACKGROUND

Fluid overload is a risk factor for organ dysfunction and death in intensive care unit (ICU) patients, but no guidelines exist for its management. We systematically reviewed benefits and harms of a single loop diuretic, the predominant treatment used for fluid overload in these patients.

METHODS

We conducted a systematic review with meta-analysis and Trial Sequential Analysis (TSA) of a single loop diuretic vs. other interventions reported in randomised clinical trials, adhering to our published protocol, the Cochrane Handbook, and PRISMA statement. We assessed the risks of bias with the ROB2-tool and certainty of evidence with GRADE. This study was registered in the International Prospective Register of Systematic Reviews (PROSPERO) (CRD42020184799).

RESULTS

We included 10 trials (804 participants), all at overall high risk of bias. For loop diuretics vs. placebo/no intervention, we found no difference in all-cause mortality (relative risk (RR) 0.72, 95% confidence interval (CI) 0.49-1.06; 4 trials; 359 participants; I2 = 0%; TSA-adjusted CI 0.15-3.48; very low certainty of evidence). Fewer serious adverse events were registered in the group treated with loop diuretics (RR 0.81, 95% CI 0.66-0.99; 6 trials; 476 participants; I2 = 0%; very low certainty of evidence), though contested by TSA (TSA-adjusted CI 0.55-1.20).

CONCLUSIONS

The evidence is very uncertain about the effect of loop diuretics on mortality and serious adverse events in adult ICU patients with fluid overload. Loop diuretics may reduce the occurrence of these outcomes, but large randomised placebo-controlled trials at low risk of bias are needed.

Biomarkers of Acute Lung Injury The Individualized Approach: for Phenotyping, Risk Stratification and Treatment Surveillance

Do we need biomarkers of lung damage and infection: For what purpose and how should they be used properly? Biomarkers of lung damage can be used for diagnosis, risk stratification/prediction, treatment surveillance and adjustment of targeted therapy. Additionally, novel "omics" methods may offer a completely different and effective way of improving the understanding of pathogenesis of lung damage and a way to develop new candidate lung damage biomarkers. In the current review, we give an overview within the field of acute lung damage of (i) disease mechanism biomarkers, (ii) of "ready to use" evidence-based biomarker-guided lung infection management, (iii) of novel strategies of inflammatory phenotyping and how this can be used to tailor corticosteroid treatment, (iv) a future perspective of where "omics" technologies and mindsets may become increasingly important in developing new strategies for treatment and for understanding the development of acute lung damage.

Mortality in critical illness: The impact of asymmetric dimethylarginine on survival-A systematic review and meta-analysis

INTRODUCTION

Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of the nitric oxide system, may be associated with an adverse outcome in critically ill patients. The aim of the present review was to clarify if plasma ADMA and the arginine-to-ADMA ratio (arginine/ADMA) are associated with mortality in critically ill patients.

METHODS

We searched PubMed, EMBASE and Web of Science/BIOSIS Previews on 31 July 2017 for studies published after 2000 including critically ill paediatric or adult patients and evaluating any association between all-cause mortality and admission ADMA and/or arginine/ADMA ratio. We pooled data from studies providing sufficient data in random effects meta-analyses.

RESULTS

We identified 15 studies including a total of 1300 patients. These studies have a medium to high risk of bias and substantial clinical heterogeneity. After contacting authors for homogenous data, six studies including 705 patients could be included in a formal meta-analysis. This analysis revealed a strong association between high plasma ADMA upon admission and mortality (pooled odds ratio 3.13; 95% confidence interval (CI) 1.78-5.51). A significant association between ADMA/arginine ratio and mortality was found in two studies only (54 patients) out of a total of six studies (564 patients).

CONCLUSIONS

A high plasma ADMA level upon admission is strongly associated with mortality in critically ill patients. However, there is no association between the arginine/ADMA ratio and mortality in this group of patients. The pathophysiological role of ADMA in circulatory collapse and its potential as a target for intervention remains to be explored.

Sepsis: Personalized Medicine Utilizing 'Omic' Technologies-A Paradigm Shift?

Sepsis has over the years proven a considerable challenge to physicians and researchers. Numerous pharmacological and non-pharmacological interventions have been tested in trials, but have unfortunately failed to improve the general prognosis. This has led to the speculation that the sepsis population may be too heterogeneous to be targeted with the traditional one treatment suits all’ approach. Recent advances in genetic and biochemical analyses now allow genotyping and biochemical characterisation of large groups of patients via the ‘omics’ technologies. These new opportunities could lead to a paradigm shift in the approach to sepsis towards personalised treatments with interventions targeted towards specific pathophysiological mechanisms activated in the patient. In this article, we review the potentials and pitfalls of using new advanced technologies to deepen our understanding of the clinical syndrome of sepsis.

Hypophosphatemia and duration of respiratory failure and mortality in critically ill patients

BACKGROUND

Hypophosphatemia has been associated with prolonged duration of respiratory failure and increased mortality in critically ill patients, but there is very limited evidence supporting the negative effects of low phosphate. We examined the association between hypophosphatemia at ICU admission and time to successful weaning and 28-day mortality.

METHODS

This was a cohort study that included all mechanically ventilated adult patients admitted to the ICU in 2013 at Nordsjaellands Hospital. Hypophosphatemia was defined as a serum level below 0.80 mmol/L. Multivariate Cox-regression was used to evaluate the effect of hypophosphatemia on mechanical ventilation and 28-day mortality. Multiple imputation was used to adjust for missing values.

RESULTS

A total of patients were admitted during the study period, of whom 190 were eligible. 122 (64.2%) had serum phosphate levels measured during the first 24 hours of admission, of whom 25 (20.5%) were found to be hypophosphatemic. About 74% of patients were successfully weaned from the ventilator within 28 days. Hypophosphatemia was not associated with this outcome (HR: 0.56; 95% CI: 0.30-1.04; P = .067). All-cause 28-day mortality was 32.6%. Hypophosphatemia was also not associated with 28-day mortality (HR: 1.64; 95% CI: 0.65-4.17; P = .447). Similar results were present in supplementary analysis where missing data were included by means of multiple imputation.

CONCLUSION

Hypophosphatemia at ICU admission was not associated with prolonged respiratory failure nor mortality. Further studies are warranted, where phosphate is measured systematically on all patients to elucidate the effect of low phosphate on relevant outcomes.

Induced hypothermia in patients with septic shock and respiratory failure (CASS): a randomised, controlled, open-label trial

BACKGROUND

Animal models of serious infection suggest that 24 h of induced hypothermia improves circulatory and respiratory function and reduces mortality. We tested the hypothesis that a reduction of core temperature to 32-34°C attenuates organ dysfunction and reduces mortality in ventilator-dependent patients with septic shock.

METHODS

In this randomised, controlled, open-label trial, we recruited patients from ten intensive care units (ICUs) in three countries in Europe and North America. Inclusion criteria for patients with severe sepsis or septic shock were a mean arterial pressure of less than 70 mm Hg, mechanical ventilation in an ICU, age at least 50 years, predicted length of stay in the ICU at least 24 h, and recruitment into the study within 6 h of fulfilling inclusion criteria. Exclusion criteria were uncontrolled bleeding, clinically important bleeding disorder, recent open surgery, pregnancy or breastfeeding, or involuntary psychiatric admission. We randomly allocated patients 1:1 (with variable block sizes ranging from four to eight; stratified by predictors of mortality, age, Acute Physiology and Chronic Health Evaluation II score, and study site) to routine thermal management or 24 h of induced hypothermia (target 32-34°C) followed by 48 h of normothermia (36-38°C). The primary endpoint was 30 day all-cause mortality in the modified intention-to-treat population (all randomly allocated patients except those for whom consent was withdrawn or who were discovered to meet an exclusion criterion after randomisation but before receiving the trial intervention). Patients and health-care professionals giving the intervention were not masked to treatment allocation, but assessors of the primary outcome were. This trial is registered with ClinicalTrials.gov, number NCT01455116.

FINDINGS

Between Nov 1, 2011, and Nov 4, 2016, we screened 5695 patients. After recruitment of 436 of the planned 560 participants, the trial was terminated for futility (220 [50%] randomly allocated to hypothermia and 216 [50%] to routine thermal management). In the hypothermia group, 96 (44·2%) of 217 died within 30 days versus 77 (35·8%) of 215 in the routine thermal management group (difference 8·4% [95% CI -0·8 to 17·6]; relative risk 1·2 [1·0-1·6]; p=0·07]).

INTERPRETATION

Among patients with septic shock and ventilator-dependent respiratory failure, induced hypothermia does not reduce mortality. Induced hypothermia should not be used in patients with septic shock.

FUNDING

Trygfonden, Lundbeckfonden, and the Danish National Research Foundation.

Induced Hypothermia in Patients with Septic Shock and Ventilator-demanding Respiratory Failure

Background

Animal models of serious infection suggest that 24 hours of induced hypothermia improves circulatory and respiratory characteristics and enhances survival, but whether therapeutic mild hypothermia in such conditions is of clinical benefit remains unknown. We, therefore, tested whether reducing core temperature to 32–34^oC in critically ill patients with septic shock and ventilator-demanding respiratory failure improves survival and reduces organ dysfunction.

Methods

In this multi-national trial, patients with septic shock were enrolled within 6 hours of onset of septic shock and ventilator-demanding respiratory failure and randomized 1:1, stratified by site (target sample = 560), to routine thermal management or 24 hours of induced hypothermia (target 32–34°C) followed by 48 hours of normothermia. Other aspects of care were per routine in each participating center. The primary endpoint was 30-day all-cause mortality.

Results

At the third ordinary interim analysis, after recruitment of 432 participants, the Data and Safety Monitoring Board recommended the trial be terminated for futility; the conditional power for rejection of the null hypothesis in favor of efficacy was null. In the induced hypothermia group, target temperature was reached within median 3.2 hours [IQR: 2.2, 4.8], and maintained for 24 hours [IQR: 24, 24] (Figure 1). There was no evidence for a difference in 30-day mortality risk in patients randomized to hypothermia (96/217) vs. routine thermal management (77/215): relative risk 1.24 [95% CI: 0.98, 1.56] (Figure 2). At the end of the temperature intervention (72 hours), more patients assigned to hypothermia were in continued shock (vasoactive medication 71% vs. 58%; P = 0.01), and fewer cooled patients had inflammatory control (32% vs. 47% had CRP decline of >30%, P = 0.005). More harm from cooling was seen in patients entering the trial with normal renal function and with normal platelet count (P for interaction < 0.05).

Conclusion

Among patients with septic shock and ventilator-demanding respiratory failure, induced hypothermia did not improve survival, but adversely affected the duration of shock, and inflammatory control. Induced hypothermia should not routinely be used in patients with septic shock.

Disclosures

All authors: No reported disclosures.

[Practical management of troponin screening after non-cardiac surgery]

Myocardial injury after non-cardiac surgery (MINS) is associated with significant morbidity and mortality. Routine troponin screening is necessary to identify patients with MINS. Although some evidence indicates benefit with aspirin and statin therapy in these patients, a number of clinical considerations must be done in the practical management of MINS. This article describes current experience with identification and treatment in Denmark of patients with MINS.

Randomized multicentre feasibility trial of intermediate care versus standard ward care after emergency abdominal surgery (InCare trial)

Background

Emergency abdominal surgery carries a considerable risk of death and postoperative complications. Early detection and timely management of complications may reduce mortality. The aim was to evaluate the effect and feasibility of intermediate care compared with standard ward care in patients who had emergency abdominal surgery.

Methods

This was a randomized clinical trial carried out in seven Danish hospitals. Eligible for inclusion were patients with an Acute Physiology And Chronic Health Evaluation (APACHE) II score of at least 10 who were ready to be transferred to the surgical ward within 24 h of emergency abdominal surgery. Participants were randomized to either intermediate care or standard surgical ward care after surgery. The primary outcome was 30-day mortality.

Results

In total, 286 patients were included in the modified intention-to-treat analysis. The trial was terminated after the interim analysis owing to slow recruitment and a lower than expected mortality rate. Eleven (7·6 per cent) of 144 patients assigned to intermediate care and 12 (8·5 per cent) of 142 patients assigned to ward care died within 30 days of surgery (odds ratio 0·91, 95 per cent c.i. 0·38 to 2·16; P = 0·828). Thirty (20·8 per cent) of 144 patients assigned to intermediate care and 37 (26·1 per cent) of 142 assigned to ward care died within the total observation period (hazard ratio 0·78, 95 per cent c.i. 0·48 to 1·26; P = 0·310).

Conclusion

Postoperative intermediate care had no statistically significant effect on 30-day mortality after emergency abdominal surgery, nor any effect on secondary outcomes. The trial was stopped prematurely owing to slow recruitment and a much lower than expected mortality rate among the enrolled patients. Registration number: NCT01209663 (http://www.clinicaltrials.gov).

Serum and plasma neutrophil gelatinase associated lipocalin (NGAL) levels are not equivalent in patients admitted to intensive care

BACKGROUND

Neutrophil gelatinase associated lipocalin (NGAL) is proposed as a biomarker of acute kidney injury (AKI). NGAL has been studied in a range of body fluids including serum and EDTA plasma. The aim of the present study was to establish relationship between serum NGAL concentrations and EDTA plasma NGAL concentrations in patients admitted to intensive care units (ICUs) and whether these determinations are directly comparable in this setting.

METHODS

NGAL was measured in 40 paired samples of serum and EDTA plasma from 25 patients admitted to intensive care with a commercial particle-enhanced turbidimetric immunoassay (The NGAL Test™, BioPorto Diagnostics A/S, Gentofte, Denmark) on a Roche Hitachi 917 (Roche-Hitachi, Inc., Tokyo, Japan) analyzer.

RESULTS

Serum NGAL concentrations ranged from 26.8 to 1,808 ng/ml (median 281 ng/ml, interquartile range (IQR) 453 ng/ml). EDTA plasma NGAL concentrations ranged from 25.7 to 1,752 ng/ml (median 225 ng/ml, IQR 352 ng/ml). The difference in NGAL concentrations in paired serum and EDTA plasma samples (serum- plasma) ranged from -13.8 to 321 ng/ml (median 79 ng/ml, IQR 116 ng/ml; difference from zero, P < 0.0001, Wilcoxon's signed rank test). Although serum and EDTA plasma values were correlated (Spearman's r = 0.95, P < 0.0001), Deming regression analysis showed a slope of 1.1 that was not significantly different from unity (95% confidence interval (CI) 1.0-1.1) and a highly significant intercept of 67.9 ng/ml with a wide confidence interval (95% CI 29.8-106).

CONCLUSION

NGAL concentration values measured in serum and EDTA plasma cannot be directly compared and should not be used as equivalents in studies of patients admitted to intensive care.