Lung Ultrasound to Determine the Effect of Lower vs. Higher PEEP on Lung Aeration in Patients without ARDS-A Substudy of a Randomized Clinical Trial.

BACKGROUND: Ventilation with lower positive end-expiratory pressure (PEEP) may cause loss of lung aeration in critically ill invasively ventilated patients. This study investigated whether a systematic lung ultrasound (LUS) scoring system can detect such changes in lung aeration in a study comparing lower versus higher PEEP in invasively ventilated patients without acute respiratory distress syndrome (ARDS). METHODS: Single center substudy of a national, multicenter, randomized clinical trial comparing lower versus higher PEEP ventilation strategy. Fifty-seven patients underwent a systematic 12-region LUS examination within 12 h and between 24 to 48 h after start of invasive ventilation, according to randomization. The primary endpoint was a change in the global LUS aeration score, where a higher value indicates a greater impairment in lung aeration. RESULTS: Thirty-three and twenty-four patients received ventilation with lower PEEP (median PEEP 1 (0-5) cm H2O) or higher PEEP (median PEEP 8 (8-8) cm H2O), respectively. Median global LUS aeration scores within 12 h and between 24 and 48 h were 8 (4 to 14) and 9 (4 to 12) (difference 1 (-2 to 3)) in the lower PEEP group, and 7 (2-11) and 6 (1-12) (difference 0 (-2 to 3)) in the higher PEEP group. Neither differences in changes over time nor differences in absolute scores reached statistical significance. CONCLUSIONS: In this substudy of a randomized clinical trial comparing lower PEEP versus higher PEEP in patients without ARDS, LUS was unable to detect changes in lung aeration.

Age-related changes in plasma biomarkers and their association with mortality in COVID-19.

BACKGROUND: Coronavirus disease 2019 (COVID-19)-induced mortality occurs predominantly in older patients. Several immunomodulating therapies seem less beneficial in these patients. The biological substrate behind these observations is unknown. The aim of this study was to obtain insight into the association between ageing, the host response and mortality in patients with COVID-19. METHODS: We determined 43 biomarkers reflective of alterations in four pathophysiological domains: endothelial cell and coagulation activation, inflammation and organ damage, and cytokine and chemokine release. We used mediation analysis to associate ageing-driven alterations in the host response with 30-day mortality. Biomarkers associated with both ageing and mortality were validated in an intensive care unit and external cohort. RESULTS: 464 general ward patients with COVID-19 were stratified according to age decades. Increasing age was an independent risk factor for 30-day mortality. Ageing was associated with alterations in each of the host response domains, characterised by greater activation of the endothelium and coagulation system and stronger elevation of inflammation and organ damage markers, which was independent of an increase in age-related comorbidities. Soluble tumour necrosis factor receptor 1, soluble triggering receptor expressed on myeloid cells 1 and soluble thrombomodulin showed the strongest correlation with ageing and explained part of the ageing-driven increase in 30-day mortality (proportion mediated: 13.0%, 12.9% and 12.6%, respectively). CONCLUSIONS: Ageing is associated with a strong and broad modification of the host response to COVID-19, and specific immune changes likely contribute to increased mortality in older patients. These results may provide insight into potential age-specific immunomodulatory targets in COVID-19.

Oxygen Consumption with High-Flow Nasal Oxygen versus Mechanical Ventilation- An International Multicenter Observational Study in COVID-19 Patients (PROXY-COVID).

The COVID-19 pandemic led to local oxygen shortages worldwide. To gain a better understanding of oxygen consumption with different respiratory supportive therapies, we conducted an international multicenter observational study to determine the precise amount of oxygen consumption with high-flow nasal oxygen (HFNO) and with mechanical ventilation. A retrospective observational study was conducted in three intensive care units (ICUs) in the Netherlands and Spain. Patients were classified as HFNO patients or ventilated patients, according to the mode of oxygen supplementation with which a patient started. The primary endpoint was actual oxygen consumption; secondary endpoints were hourly and total oxygen consumption during the first two full calendar days. Of 275 patients, 147 started with HFNO and 128 with mechanical ventilation. Actual oxygen use was 4.9-fold higher in patients who started with HFNO than in patients who started with ventilation (median 14.2 [8.4-18.4] versus 2.9 [1.8-4.1] L/minute; mean difference = 11.3 [95% CI 11.0-11.6] L/minute; P < 0.01). Hourly and total oxygen consumption were 4.8-fold (P < 0.01) and 4.8-fold (P < 0.01) higher. Actual oxygen consumption, hourly oxygen consumption, and total oxygen consumption are substantially higher in patients that start with HFNO compared with patients that start with mechanical ventilation. This information may help hospitals and ICUs predicting oxygen needs during high-demand periods and could guide decisions regarding the source of distribution of medical oxygen.

Myocardial Function during Ventilation with Lower versus Higher Positive End-Expiratory Pressure in Patients without ARDS.

The aim of this study was to investigate whether lower PEEP (positive end-expiratory pressure) had beneficial effects on myocardial function among intensive care unit (ICU) patients without acute respiratory distress syndrome (ARDS) compared to higher PEEP. In this pre-planned substudy of a randomized controlled trial (RELAx), comparing lower to higher PEEP, 44 patients underwent transthoracic echocardiography. The exclusion criteria were known poor left ventricular function and severe shock requiring high dosages of norepinephrine. To create contrast, we also excluded patients who received PEEP between 2 cmH2O and 7 cmH2O in the two randomization arms of the study. The primary outcome was the right ventricular myocardial performance index (MPI), a measure of systolic and diastolic function. The secondary outcomes included systolic and diastolic function parameters. A total of 20 patients were ventilated with lower PEEP (mean ± SD, 0 ± 1 cmH2O), and 24 patients, with higher PEEP (8 ± 1 cmH2O) (mean difference, -8 cmH2O; 95% CI: -8.1 to -7.9 cmH2O; p = 0.01). The tidal volume size was low in both groups (median (IQR), 7.2 (6.3 to 8.1) versus 7.0 (5.3 to 9.1) ml/kg PBW; p = 0.97). The median right ventricular MPI was 0.32 (IQR, 0.26 to 0.39) in the lower-PEEP group versus 0.38 (0.32 to 0.41) in the higher-PEEP group; the median difference was -0.03; 95% CI: -0.11 to 0.03; p = 0.33. The other systolic and diastolic parameters were similar. In patients without ARDS ventilated with a low tidal volume, a lower PEEP had no beneficial effects on the right ventricular MPI.

Effect of Automated Closed-loop ventilation versus convenTional VEntilation on duration and quality of ventilation in critically ill patients (ACTiVE) - study protocol of a randomized clinical trial.

BACKGROUND: INTELLiVENT-Adaptive Support Ventilation (ASV) is a fully automated closed-loop mode of ventilation for use in critically ill patients. Evidence for benefit of INTELLiVENT-ASV in comparison to ventilation that is not fully automated with regard to duration of ventilation and quality of breathing is largely lacking. We test the hypothesis that INTELLiVENT-ASV shortens time spent on a ventilator and improves the quality of breathing. METHODS: The "Effects of Automated Closed-loop VenTilation versus Conventional Ventilation on Duration and Quality of Ventilation" (ACTiVE) study is an international, multicenter, two-group randomized clinical superiority trial. In total, 1200 intensive care unit (ICU) patients with an anticipated duration of ventilation of > 24 h will be randomly assigned to one of the two ventilation strategies. Investigators screen patients aged 18 years or older at start of invasive ventilation in the ICU. Patients either receive automated ventilation by means of INTELLiVENT-ASV, or ventilation that is not automated by means of a conventional ventilation mode. The primary endpoint is the number of days free from ventilation and alive at day 28; secondary endpoints are quality of breathing using granular breath-by-breath analysis of ventilation parameters and variables in a time frame of 24 h early after the start of invasive ventilation, duration of ventilation in survivors, ICU and hospital length of stay (LOS), and mortality rates in the ICU and hospital, and at 28 and 90 days. DISCUSSION: ACTiVE is one of the first randomized clinical trials that is adequately powered to compare the effects of automated closed-loop ventilation versus conventional ventilation on duration of ventilation and quality of breathing in invasively ventilated critically ill patients. The results of ACTiVE will support intensivist in their choices regarding the use of automated ventilation. TRIAL REGISTRATION: ACTiVE is registered in clinicaltrials.gov (study identifier: NCT04593810 ) on 20 October 2020.

Clinical characteristics, physiological features, and outcomes associated with hypercapnia in patients with acute hypoxemic respiratory failure due to COVID-19---insights from the PRoVENT-COVID study.

PURPOSE: We determined the incidence of hypercapnia and associations with outcome in invasively ventilated COVID-19 patients. METHODS: Posthoc analysis of a national, multicenter, observational study in 22 ICUs. Patients were classified as 'hypercapnic' or 'normocapnic' in the first three days of invasive ventilation. Primary endpoint was prevalence of hypercapnia. Secondary endpoints were ventilator parameters, length of stay (LOS) in ICU and hospital, and mortality in ICU, hospital, at day 28 and 90. RESULTS: Of 824 patients, 485 (58.9%) were hypercapnic. Hypercapnic patients had a higher BMI and had COPD, severe ARDS and venous thromboembolic events more often. Hypercapnic patients were ventilated with lower tidal volumes, higher respiratory rates, higher driving pressures, and with more mechanical power of ventilation. Hypercapnic patients had comparable minute volumes but higher ventilatory ratios than normocapnic patients. In hypercapnic patients, ventilation and LOS in ICU and hospital was longer, but mortality was comparable to normocapnic patients. CONCLUSION: Hypercapnia occurs often in invasively ventilated COVID-19 patients. Main differences between hypercapnic and normocapnic patients are severity of ARDS, occurrence of venous thromboembolic events, and a higher ventilation ratio. Hypercapnia has an association with duration of ventilation and LOS in ICU and hospital, but not with mortality.

The effect of age on ventilation management and clinical outcomes in critically ill COVID-19 patients--insights from the PRoVENT-COVID study.

INTRODUCTION: We analyzed the association of age with ventilation practice and outcomes in critically ill COVID-19 patients requiring invasive ventilation. METHODS: Posthoc analysis of the PRoVENT-COVID study, an observational study performed in 22 ICUs in the first 3 months of the national outbreak in the Netherlands. The coprimary endpoint was a set of ventilator parameters, including tidal volume normalized for predicted bodyweight, positive end-expiratory pressure, driving pressure, and respiratory system compliance in the first 4 days of invasive ventilation. Secondary endpoints were other ventilation parameters, the use of rescue therapies, pulmonary and extrapulmonary complications in the first 28 days in the ICU, hospital- and ICU stay, and mortality. RESULTS: 1122 patients were divided into four groups based on age quartiles. No meaningful differences were found in ventilation parameters and in the use of rescue therapies for refractory hypoxemia in the first 4 days of invasive ventilation. Older patients received more often a tracheostomy, developed more frequently acute kidney injury and myocardial infarction, stayed longer in hospital and ICU, and had a higher mortality. CONCLUSIONS: In this cohort of invasively ventilated critically ill COVID-19 patients, age had no effect on ventilator management. Higher age was associated with more complications, longer length of stay in ICU and hospital and a higher mortality.

Effect of INTELLiVENT-ASV versus Conventional Ventilation on Ventilation Intensity in Patients with COVID-19 ARDS-An Observational Study.

Driving pressure (ΔP) and mechanical power (MP) are associated with outcomes in critically ill patients, irrespective of the presence of Acute Respiratory Distress Syndrome (ARDS). INTELLiVENT-ASV, a fully automated ventilatory mode, controls the settings that affect ΔP and MP. This study compared the intensity of ventilation (ΔP and MP) with INTELLiVENT-ASV versus conventional ventilation in a cohort of COVID-19 ARDS patients in two intensive care units in the Netherlands. The coprimary endpoints were ΔP and MP before and after converting from conventional ventilation to INTELLiVENT-ASV. Compared to conventional ventilation, INTELLiVENT-ASV delivered ventilation with a lower ΔP and less MP. With conventional ventilation, ΔP was 13 cmH2O, and MP was 21.5 and 24.8 J/min, whereas with INTELLiVENT-ASV, ΔP was 11 and 10 cmH2O (mean difference -2 cm H2O (95 %CI -2.5 to -1.2 cm H2O), p < 0.001) and MP was 18.8 and 17.5 J/min (mean difference -7.3 J/Min (95% CI -8.8 to -5.8 J/min), p < 0.001). Conversion from conventional ventilation to INTELLiVENT-ASV resulted in a lower intensity of ventilation. These findings may favor the use of INTELLiVENT-ASV in COVID-19 ARDS patients, but future studies remain needed to see if the reduction in the intensity of ventilation translates into clinical benefits.

Longitudinal respiratory subphenotypes in patients with COVID-19-related acute respiratory distress syndrome: results from three observational cohorts.

BACKGROUND: Patients with COVID-19-related acute respiratory distress syndrome (ARDS) have been postulated to present with distinct respiratory subphenotypes. However, most phenotyping schema have been limited by sample size, disregard for temporal dynamics, and insufficient validation. We aimed to identify respiratory subphenotypes of COVID-19-related ARDS using unbiased data-driven approaches. METHODS: PRoVENT-COVID was an investigator-initiated, national, multicentre, prospective, observational cohort study at 22 intensive care units (ICUs) in the Netherlands. Consecutive patients who had received invasive mechanical ventilation for COVID-19 (aged 18 years or older) served as the derivation cohort, and similar patients from two ICUs in the USA served as the replication cohorts. COVID-19 was confirmed by positive RT-PCR. We used latent class analysis to identify subphenotypes using clinically available respiratory data cross-sectionally at baseline, and longitudinally using 8-hourly data from the first 4 days of invasive ventilation. We used group-based trajectory modelling to evaluate trajectories of individual variables and to facilitate potential clinical translation. The PRoVENT-COVID study is registered with ClinicalTrials.gov, NCT04346342. FINDINGS: Between March 1, 2020, and May 15, 2020, 1007 patients were admitted to participating ICUs in the Netherlands, and included in the derivation cohort. Data for 288 patients were included in replication cohort 1 and 326 in replication cohort 2. Cross-sectional latent class analysis did not identify any underlying subphenotypes. Longitudinal latent class analysis identified two distinct subphenotypes. Subphenotype 2 was characterised by higher mechanical power, minute ventilation, and ventilatory ratio over the first 4 days of invasive mechanical ventilation than subphenotype 1, but PaO2/FiO2, pH, and compliance of the respiratory system did not differ between the two subphenotypes. 185 (28%) of 671 patients with subphenotype 1 and 109 (32%) of 336 patients with subphenotype 2 had died at day 28 (p=0·10). However, patients with subphenotype 2 had fewer ventilator-free days at day 28 (median 0, IQR 0-15 vs 5, 0-17; p=0·016) and more frequent venous thrombotic events (109 [32%] of 336 patients vs 176 [26%] of 671 patients; p=0·048) compared with subphenotype 1. Group-based trajectory modelling revealed trajectories of ventilatory ratio and mechanical power with similar dynamics to those observed in latent class analysis-derived trajectory subphenotypes. The two trajectories were: a stable value for ventilatory ratio or mechanical power over the first 4 days of invasive mechanical ventilation (trajectory A) or an upward trajectory (trajectory B). However, upward trajectories were better independent prognosticators for 28-day mortality (OR 1·64, 95% CI 1·17-2·29 for ventilatory ratio; 1·82, 1·24-2·66 for mechanical power). The association between upward ventilatory ratio trajectories (trajectory B) and 28-day mortality was confirmed in the replication cohorts (OR 4·65, 95% CI 1·87-11·6 for ventilatory ratio in replication cohort 1; 1·89, 1·05-3·37 for ventilatory ratio in replication cohort 2). INTERPRETATION: At baseline, COVID-19-related ARDS has no consistent respiratory subphenotype. Patients diverged from a fairly homogenous to a more heterogeneous population, with trajectories of ventilatory ratio and mechanical power being the most discriminatory. Modelling these parameters alone provided prognostic value for duration of mechanical ventilation and mortality. FUNDING: Amsterdam UMC.

Association of early positive end-expiratory pressure settings with ventilator-free days in patients with coronavirus disease 2019 acute respiratory distress syndrome: A secondary analysis of the Practice of VENTilation in COVID-19 study.

BACKGROUND: There is uncertainty about how much positive end-expiratory pressure (PEEP) should be used in patients with acute respiratory distress syndrome (ARDS) due to coronavirus disease 2019 (COVID-19). OBJECTIVE: To investigate whether a higher PEEP strategy is superior to a lower PEEP strategy regarding the number of ventilator-free days (VFDs). DESIGN: Multicentre observational study conducted from 1 March to 1 June 2020. SETTING AND PATIENTS: Twenty-two ICUs in The Netherlands and 933 invasively ventilated COVID-19 ARDS patients. INTERVENTIONS: Patients were categorised retrospectively as having received invasive ventilation with higher (n=259) or lower PEEP (n=674), based on the high and low PEEP/FiO2 tables of the ARDS Network, and using ventilator settings and parameters in the first hour of invasive ventilation, and every 8 h thereafter at fixed time points during the first four calendar days. We also used propensity score matching to control for observed confounding factors that might influence outcomes. MAIN OUTCOMES AND MEASURES: The primary outcome was the number of VFDs. Secondary outcomes included distant organ failures including acute kidney injury (AKI) and use of renal replacement therapy (RRT), and mortality. RESULTS: In the unmatched cohort, the higher PEEP strategy had no association with the median [IQR] number of VFDs (2.0 [0.0 to 15.0] vs. 0.0 [0.0 to 16.0] days). The median (95% confidence interval) difference was 0.21 (-3.34 to 3.78) days, P = 0.905. In the matched cohort, the higher PEEP group had an association with a lower median number of VFDs (0.0 [0.0 to 14.0] vs. 6.0 [0.0 to 17.0] days) a median difference of -4.65 (-8.92 to -0.39) days, P = 0.032. The higher PEEP strategy had associations with higher incidence of AKI (in the matched cohort) and more use of RRT (in the unmatched and matched cohorts). The higher PEEP strategy had no association with mortality. CONCLUSION: In COVID-19 ARDS, use of higher PEEP may be associated with a lower number of VFDs, and may increase the incidence of AKI and need for RRT. TRIAL REGISTRATION: Practice of VENTilation in COVID-19 is registered at ClinicalTrials.gov, NCT04346342.

Practice of adjunctive treatments in critically ill COVID-19 patients-rational for the multicenter observational PRoAcT-COVID study in The Netherlands.

BACKGROUND: Patients with coronavirus disease 2019 (COVID-19) may need hospitalization for supplemental oxygen, and some need intensive care unit (ICU) admission for escalation of care. Practice of adjunctive and supportive treatments remain uncertain and may vary widely between countries, within countries between hospitals, and possibly even within ICUs. We aim to investigate practice of adjunctive and supportive treatments, and their associations with outcome, in critically ill COVID-19 patients. METHODS: The 'PRactice of Adjunctive Treatments in Intensive Care Unit Patients with Coronavirus Disease 2019' (PRoAcT-COVID) study is a national, observational study to be undertaken in a large set of ICUs in The Netherlands. The PRoAcT-COVID includes consecutive ICU patients, admitted because of COVID-19 to one of the participating ICUs during a 3-month period. Daily follow-up lasts 28 days. The primary endpoint is a combination of adjunctive treatments, including types of oxygen support, ventilation, rescue therapies for hypoxemia refractory to supplementary oxygen or during invasive ventilation, other adjunctive and supportive treatments, and experimental therapies. We will also collect tracheostomy rate, duration of invasive ventilation and ventilator-free days and alive at day 28 (VFD-28), ICU and hospital length of stay, and the mortality rates in the ICU, hospital and at day 90. DISCUSSION: The PRoAcT-COVID study is an observational study combining high density treatment data with relevant clinical outcomes. Information on treatment practices, and their associations with outcomes in COVID-19 patients in highly and urgently needed. The results of the PRoAcT-COVID study will be rapidly available, and circulated through online presentations, such as webinars and electronic conferences, and publications in peer-reviewed journals-findings will also be presented at a dedicated website. At request, and after agreement of the PRoAcT-COVID steering committee, source data will be made available through local, regional and national anonymized datasets. TRIAL REGISTRATION: The PRoAcT-COVID study is registered at clinicaltrials.gov (study identifier NCT04719182).

Dead space estimates may not be independently associated with 28-day mortality in COVID-19 ARDS.

BACKGROUND: Estimates for dead space ventilation have been shown to be independently associated with an increased risk of mortality in the acute respiratory distress syndrome and small case series of COVID-19-related ARDS. METHODS: Secondary analysis from the PRoVENT-COVID study. The PRoVENT-COVID is a national, multicenter, retrospective observational study done at 22 intensive care units in the Netherlands. Consecutive patients aged at least 18 years were eligible for participation if they had received invasive ventilation for COVID-19 at a participating ICU during the first month of the national outbreak in the Netherlands. The aim was to quantify the dynamics and determine the prognostic value of surrogate markers of wasted ventilation in patients with COVID-19-related ARDS. RESULTS: A total of 927 consecutive patients admitted with COVID-19-related ARDS were included in this study. Estimations of wasted ventilation such as the estimated dead space fraction (by Harris-Benedict and direct method) and ventilatory ratio were significantly higher in non-survivors than survivors at baseline and during the following days of mechanical ventilation (p < 0.001). The end-tidal-to-arterial PCO2 ratio was lower in non-survivors than in survivors (p < 0.001). As ARDS severity increased, mortality increased with successive tertiles of dead space fraction by Harris-Benedict and by direct estimation, and with an increase in the VR. The same trend was observed with decreased levels in the tertiles for the end-tidal-to-arterial PCO2 ratio. After adjustment for a base risk model that included chronic comorbidities and ventilation- and oxygenation-parameters, none of the dead space estimates measured at the start of ventilation or the following days were significantly associated with 28-day mortality. CONCLUSIONS: There is significant impairment of ventilation in the early course of COVID-19-related ARDS but quantification of this impairment does not add prognostic information when added to a baseline risk model. TRIAL REGISTRATION: ISRCTN04346342. Registered 15 April 2020. Retrospectively registered.

Ventilation management in acute respiratory failure related to COVID-19 versus ARDS from another origin - a descriptive narrative review.

INTRODUCTION: It is uncertain whether ventilation in patients with acute respiratory failure related to coronavirus disease 2019 (COVID-19) differs from that in patients with acute respiratory distress syndrome (ARDS) from another origin. AREAS COVERED: We undertook two literature searches in PubMed to identify observational studies reporting on ventilation management--one in patients with acute respiratory failure related to COVID-19, and one in patients with ARDS from another origin. The searches identified 14 studies in patients with acute respiratory failure related to COVID-19, and 8 studies in patients with ARDS from another origin. EXPERT OPINION: In patients with acute respiratory failure related to COVID-19, ventilation management seems to be similar to that of patients with ARDS from another origin. The future lies in studies focused on personalized treatment of ARDS of all origins, including COVID-19.

Ventilation management and clinical outcomes in invasively ventilated patients with COVID-19 (PRoVENT-COVID): a national, multicentre, observational cohort study.

BACKGROUND: Little is known about the practice of ventilation management in patients with COVID-19. We aimed to describe the practice of ventilation management and to establish outcomes in invasively ventilated patients with COVID-19 in a single country during the first month of the outbreak. METHODS: PRoVENT-COVID is a national, multicentre, retrospective observational study done at 18 intensive care units (ICUs) in the Netherlands. Consecutive patients aged at least 18 years were eligible for participation if they had received invasive ventilation for COVID-19 at a participating ICU during the first month of the national outbreak in the Netherlands. The primary outcome was a combination of ventilator variables and parameters over the first 4 calendar days of ventilation: tidal volume, positive end-expiratory pressure (PEEP), respiratory system compliance, and driving pressure. Secondary outcomes included the use of adjunctive treatments for refractory hypoxaemia and ICU complications. Patient-centred outcomes were ventilator-free days at day 28, duration of ventilation, duration of ICU and hospital stay, and mortality. PRoVENT-COVID is registered at ClinicalTrials.gov (NCT04346342). FINDINGS: Between March 1 and April 1, 2020, 553 patients were included in the study. Median tidal volume was 6·3 mL/kg predicted bodyweight (IQR 5·7-7·1), PEEP was 14·0 cm H2O (IQR 11·0-15·0), and driving pressure was 14·0 cm H2O (11·2-16·0). Median respiratory system compliance was 31·9 mL/cm H2O (26·0-39·9). Of the adjunctive treatments for refractory hypoxaemia, prone positioning was most often used in the first 4 days of ventilation (283 [53%] of 530 patients). The median number of ventilator-free days at day 28 was 0 (IQR 0-15); 186 (35%) of 530 patients had died by day 28. Predictors of 28-day mortality were gender, age, tidal volume, respiratory system compliance, arterial pH, and heart rate on the first day of invasive ventilation. INTERPRETATION: In patients with COVID-19 who were invasively ventilated during the first month of the outbreak in the Netherlands, lung-protective ventilation with low tidal volume and low driving pressure was broadly applied and prone positioning was often used. The applied PEEP varied widely, despite an invariably low respiratory system compliance. The findings of this national study provide a basis for new hypotheses and sample size calculations for future trials of invasive ventilation for COVID-19. These data could also help in the interpretation of findings from other studies of ventilation practice and outcomes in invasively ventilated patients with COVID-19. FUNDING: Amsterdam University Medical Centers, location Academic Medical Center.

PRactice of VENTilation in Patients with Novel Coronavirus Disease (PRoVENT-COVID): rationale and protocol for a national multicenter observational study in The Netherlands.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic is rapidly expanding across the world, with more than 100,000 new cases each day as of end-June 2020. Healthcare workers are struggling to provide the best care for COVID-19 patients. Approaches for invasive ventilation vary widely between and within countries and new insights are acquired rapidly. We aim to investigate invasive ventilation practices and outcome in COVID-19 patients in the Netherlands. METHODS: PRoVENT-COVID ('study of PRactice of VENTilation in COVID-19') is an investigator-initiated national, multicenter observational study to be undertaken in intensive care units (ICUs) in The Netherlands. Consecutive COVID-19 patients aged 18 years or older, who are receiving invasive ventilation in the participating ICUs, are to be enrolled during a 10-week period, with a daily follow-up of 7 days. The primary outcome is ventilatory management (including tidal volume expressed as mL/kg predicted body weight and positive end-expiratory pressure expressed as cmH2O) during the first 3 days of ventilation. Secondary outcomes include other ventilatory variables, use of rescue therapies for refractory hypoxemia such as prone positioning and extracorporeal membrane oxygenation, use of sedatives, vasopressors and inotropes; daily cumulative fluid balances; acute kidney injury; ventilator-free days and alive at day 28 (VFD-28), duration of ICU and hospital stay, and ICU, hospital and 90-day mortality. DISCUSSION: PRoVENT-COVID will be the largest observational study to date, with high density ventilatory data and major outcomes. There is urgent need for a better understanding of ventilation practices, and the effects of ventilator settings on outcomes in COVID-19 patients. The results of PRoVENT-COVID will be rapidly disseminated through electronic presentations, such as webinars and electronic conferences, and publications in international peer-reviewed journals. Access to source data will be made available through local, regional and national anonymized datasets on request, and after agreement of the PRoVENT-COVID steering committee. TRIAL REGISTRATION: PRoVENT-COVID is registered at clinicaltrials.gov (identifier NCT04346342).

Does asymptomatic recurrent diffuse capillary C4d complement deposition impair cardiac allograft function?

BACKGROUND: The aim of this study was to evaluate whether asymptomatic recurrent (≥2) antibody-mediated rejection (pAMR 1+), defined as diffuse capillary C4d immunostaining (rAMR) on endomyocardial biopsies (EMBs), during the first year after heart transplantation impairs left ventricular (LV) function. METHODS: Fifty-four consecutive heart transplant patients who survived well (New York Heart Association ≤2 and EF≥55%) the first month after transplantation were enrolled and prospectively underwent 490 echocardiographies and EMB. Asymptomatic rAMR without histopathologic findings was evaluated as a risk factor for deterioration of graft function. Primary endpoint, assessed 1 year after transplantation, was development of LV dysfunction and/or adverse remodeling according to pre-specified echo parameters. RESULTS: During the first year from transplantation, rAMR occurred in five patients. Recurrent AMR was associated with a significant higher risk to develop LV concentric hypertrophy (OR 3.6, 95% CI: 1.8-7.0, P=.02) or reduced lateral S' peak velocity (OR 2.3, 95% CI: 1.5-3.6, P=.03). Patients with rAMR showed significative adverse graft remodeling (ΔLV end-diastolic volume: +16±12.3 vs -0.2±14.4 mL; P=.02) and deterioration of graft function (Δlateral S' peak velocity: -3.3±3 vs -0.4±2.9 cm/s; P=.03). CONCLUSIONS: Recurrent asymptomatic diffuse capillary C4d immunostaining may play a role in the early development of cardiac allograft adverse remodeling and dysfunction.

Prolonged QT interval in ST-elevation myocardial infarction: predictors and prognostic value in medium-term follow-up.

AIMS: The prognostic role of corrected QT interval in ST-elevation myocardial infarction is still unknown. This study aims to identify the prognostic value of corrected QT interval prolongation (≥480 ms) in acute coronary syndrome. METHODS: One hundred and eighty-five consecutive patients with ST-elevation myocardial infarction were prospectively enrolled and electrocardiographic monitoring of corrected QT interval was performed during the hospitalization. RESULTS: Over a mean period of 17.6 ±â€Š11 months, 16 (8.6%) patients died because of cardiovascular diseases, 6 (3.2%) patients experienced aborted sudden cardiac death, 3 (1.6%) cerebral ischemic strokes, 11 (6%) recurrent myocardial ischemia and 6 (3.2%) acute heart failure. At univariate analysis a corrected QT interval peak of at least 480 ms relates to cardiovascular death (P < 0.001), aborted sudden cardiac death (P = 0.037), cerebral ischemic stroke (P = 0.016) and recurrences of myocardial infarction (P = 0.032). Multivariate analysis confirms its role an independent predictor of cardiovascular death [odds ratio 6.38, 95% confidence interval (CI) 1.77-22.92, P = 0.004], together with an ejection fraction of 35% or less (odds ratio 4.20, 95% CI 1.24-14.16, P = 0.021). The presence of either corrected QT of at least 480 ms or ejection fraction of 35% or less increases the sensitivity and the accuracy to correctly predict cardiovascular death without a significant reduction in specificity (sensitivity 88%, specificity 69%, accuracy 88%, area under curve 0.83, 95% CI 0.72-0.94, P < 0.01). CONCLUSION: A corrected QT interval peak of at least 480 ms in the acute phase of ST-elevation myocardial infarction is an independent predictor of cardiovascular death. Its association with reduced ejection fraction (≤35%) increases risk stratification accuracy.

Clinical and prognostic role of ammonia in advanced decompensated heart failure. The cardio-abdominal syndrome?

BACKGROUND: Advanced heart failure is associated with end-organ damage. Recent literature suggested an intriguing crosstalk between failing heart, abdomen and kidneys. Venous ammonia, as a by-product of the gut, could be a marker of abdominal injury in heart failure patients. The aim of the study was to investigate the clinical and prognostic role of ammonia in patients with advanced decompensated heart failure (ADHF). METHODS & RESULTS: 90 patients admitted with ADHF were prospectively studied. The prognostic role of ammonia at admission was evaluated. Primary end-points were: a composite of cardiac death, urgent heart transplantation and mechanical circulatory support at 3 months and need for renal replacement therapies (RRT). In the study cohort (age 59.0 ± 12.0 years, FE 21.6 ± 9.0%, INTERMACS profile 3.7 ± 0.9, creatinine 1.71 ± 0.95 mg/dl) 27 patients (30%) underwent the cardiac composite endpoint, while 9 patients (10%) needed RRT. At ROC curve analysis ammonia ≥ 130 µg/dl (abdominal damage) showed the best diagnostic accuracy. At multivariate analysis abdominal damage predicted the cardiac composite endpoint. Abdominal damage further increased risk among patient with cold profile at admission (HR 2.7, 95% CI 1.1-7.0, p = 0.046). At multivariate analysis abdominal damage also predicted need for RRT (OR 10.8, 95% CI 1.5-75.8, p = 0.017). The combined use of estimated right atrial pressure and ammonia showed the highest diagnostic accuracy and a very high specificity in prediction of need for RRT. CONCLUSION: In a selected population admitted for ADHF ammonia, as a marker of abdominal derangement, predicted adverse cardiac events and need for RRT.

Clinical assessment of hypoperfusion in acute heart failure ­ evergreen or antique?

BACKGROUND: Cold hemodynamic profile assessed on physical examination predicts survival, although it has low specificity and low reproducibility. We herein propose a new cold profile definition (Cold Modified 2014), including renal and hepatic damage. The aim of the study was to evaluate the additional prognostic value of clinical and laboratory identification of hypoperfusion over hypotension in the setting of advanced acute heart failure (AHF). METHODS AND RESULTS: After preliminary analysis on derivation cohort, we studied 223 consecutive NYHA III-IV patients admitted with AHF requiring intensive care. Cold Modified 2014 definition included non-invasive hemodynamic assessment, renal and hepatic injury. Primary endpoint was a composite of cardiac death, urgent heart transplantation and mechanical circulatory support at 6 months. In the validation cohort (age, 60.5 ± 12.8 years; ejection fraction 25.6 ± 8.2%, systolic blood pressure [SBP] 104.3 ± 26.1 mmHg) 77 reached the composite endpoint. Among SBP, ADHERE model, cold profile at admission and INTERMACS profile at 48 h, cold profile had the best diagnostic accuracy. On multivariate analysis only cold profile and INTERMACS predicted events, while SBP <115 mmHg and high risk on ADHERE did not. Cold Modified 2014 was more accurate than the old definition. Net reclassification improvement for Cold Modified 2014 over the old definition was 25.8%. CONCLUSIONS: This prospective study demonstrated the additional prognostic role of hypoperfusion assessment over hypotension in patients with AHF. Cold Modified 2014 improved risk stratification in advanced AHF patients.