Incidence, risk factors and outcome of acute kidney injury in critically ill COVID-19 patients in Tyrol, Austria: a prospective multicenter registry study.

INTRODUCTION: Acute kidney injury is a frequent complication in critically ill patients with and without COVID-19. The aim of this study was to evaluate the incidence of, and risk factors for, acute kidney injury and its effect on clinical outcomes of critically ill COVID-19 patients in Tyrol, Austria. METHODS: This multicenter prospective registry study included adult patients with a SARS-CoV-2 infection confirmed by polymerase chain reaction, who were treated in one of the 12 dedicated intensive care units during the COVID-19 pandemic from February 2020 until May 2022. RESULTS: In total, 1042 patients were included during the study period. The median age of the overall cohort was 66 years. Of the included patients, 267 (26%) developed acute kidney injury during their intensive care unit stay. In total, 12.3% (n = 126) required renal replacement therapy with a median duration of 9 (IQR 3-18) days. In patients with acute kidney injury the rate of invasive mechanical ventilation was significantly higher with 85% (n = 227) compared to 41% (n = 312) in the no acute kidney injury group (p < 0.001). The most important risk factors for acute kidney injury were invasive mechanical ventilation (OR = 4.19, p < 0.001), vasopressor use (OR = 3.17, p < 0.001) and chronic kidney disease (OR = 2.30, p < 0.001) in a multivariable logistic regression analysis. Hospital and intensive care unit mortality were significantly higher in patients with acute kidney injury compared to patients without acute kidney injury (Hospital mortality: 52.1% vs. 17.2%, p < 0.001, ICU-mortality: 47.2% vs. 14.7%, p < 0.001). CONCLUSION: As in non-COVID-19 patients, acute kidney injury is clearly associated with increased mortality in critically ill COVID-19 patients. Among known risk factors, invasive mechanical ventilation has been identified as an independent and strong predictor of acute kidney injury.

[Hyponatremia : Etiology, diagnosis and acute therapy]. / Hyponatriämie : Ätiologie, Diagnostik und Akuttherapie.

Hyponatremia is one of the most common electrolyte disorders in emergency departments and hospitalized patients. Serum sodium concentration is controlled by osmoregulation and volume regulation. Both pathways are regulated via the release of antidiuretic hormone (ADH). Syndrome of inappropriate release of ADH (SIADH) may be caused by neoplasms or pneumonia but may also be triggered by drug use or drug abuse. Excessive fluid intake may also result in a decrease in serum sodium concentration. Rapid alteration in serum sodium concentration leads to cell swelling or cell shrinkage, which primarily causes neurological symptoms. The dynamics of development of hyponatremia and its duration are crucial. In addition to blood testing, a clinical examination and urine analysis are essential in the differential diagnosis of hyponatremia.

A proteomic survival predictor for COVID-19 patients in intensive care.

Global healthcare systems are challenged by the COVID-19 pandemic. There is a need to optimize allocation of treatment and resources in intensive care, as clinically established risk assessments such as SOFA and APACHE II scores show only limited performance for predicting the survival of severely ill COVID-19 patients. Additional tools are also needed to monitor treatment, including experimental therapies in clinical trials. Comprehensively capturing human physiology, we speculated that proteomics in combination with new data-driven analysis strategies could produce a new generation of prognostic discriminators. We studied two independent cohorts of patients with severe COVID-19 who required intensive care and invasive mechanical ventilation. SOFA score, Charlson comorbidity index, and APACHE II score showed limited performance in predicting the COVID-19 outcome. Instead, the quantification of 321 plasma protein groups at 349 timepoints in 50 critically ill patients receiving invasive mechanical ventilation revealed 14 proteins that showed trajectories different between survivors and non-survivors. A predictor trained on proteomic measurements obtained at the first time point at maximum treatment level (i.e. WHO grade 7), which was weeks before the outcome, achieved accurate classification of survivors (AUROC 0.81). We tested the established predictor on an independent validation cohort (AUROC 1.0). The majority of proteins with high relevance in the prediction model belong to the coagulation system and complement cascade. Our study demonstrates that plasma proteomics can give rise to prognostic predictors substantially outperforming current prognostic markers in intensive care.

Changes in characteristics and outcomes of critically ill COVID-19 patients in Tyrol (Austria) over 1 year.

BACKGROUND: Widely varying mortality rates of critically ill Coronavirus disease 19 (COVID-19) patients in the world highlighted the need for local surveillance of baseline characteristics, treatment strategies and outcome. We compared two periods of the COVID-19 pandemic to identify important differences in characteristics and therapeutic measures and their influence on the outcome of critically ill COVID-19 patients. METHODS: This multicenter prospective register study included all patients with a SARS-CoV­2 infection confirmed by polymerase chain reaction, who were treated in 1 of the 12 intensive care units (ICU) from 8 hospitals in Tyrol, Austria during 2 defined periods (1 February 2020 until 17 July: first wave and 18 July 2020 until 22 February 2021: second wave) of the COVID-19 pandemic. RESULTS: Overall, 508 patients were analyzed. The majority (n = 401) presented during the second wave, where the median age was significantly higher (64 years, IQR 54-74 years vs. 72 years, IQR 62-78 years, p < 0.001). Invasive mechanical ventilation was less frequent during the second period (50.5% vs 67.3%, p = 0.003), as was the use of vasopressors (50.3% vs. 69.2%, p = 0.001) and renal replacement therapy (12.0% vs. 19.6%, p = 0.061), which resulted in shorter ICU length of stay (10 days, IQR 5-18 days vs. 18 days, IQR 5-31 days, p < 0.001). Nonetheless, ICU mortality did not change (28.9% vs. 21.5%, p = 0.159) and hospital mortality even increased (22.4% vs. 33.4%, p = 0.039) in the second period. Age, frailty and the number of comorbidities were significant predictors of hospital mortality in a multivariate logistic regression analysis of the overall cohort. CONCLUSION: Advanced treatment strategies and learning effects over time resulted in reduced rates of mechanical ventilation and vasopressor use in the second wave associated with shorter ICU length of stay. Despite these improvements, age appears to be a dominant factor for hospital mortality in critically ill COVID-19 patients.

A time-resolved proteomic and prognostic map of COVID-19.

COVID-19 is highly variable in its clinical presentation, ranging from asymptomatic infection to severe organ damage and death. We characterized the time-dependent progression of the disease in 139 COVID-19 inpatients by measuring 86 accredited diagnostic parameters, such as blood cell counts and enzyme activities, as well as untargeted plasma proteomes at 687 sampling points. We report an initial spike in a systemic inflammatory response, which is gradually alleviated and followed by a protein signature indicative of tissue repair, metabolic reconstitution, and immunomodulation. We identify prognostic marker signatures for devising risk-adapted treatment strategies and use machine learning to classify therapeutic needs. We show that the machine learning models based on the proteome are transferable to an independent cohort. Our study presents a map linking routinely used clinical diagnostic parameters to plasma proteomes and their dynamics in an infectious disease.

Low bicarbonate replacement fluid normalizes metabolic alkalosis during continuous veno-venous hemofiltration with regional citrate anticoagulation.

BACKGROUND: Metabolic alkalosis is a frequently occurring problem during continuous veno-venous hemofiltration (CVVH) with regional citrate anticoagulation (RCA). This study aimed to evaluate the effectiveness of switching from high to low bicarbonate (HCO3-) replacement fluid in alkalotic critically ill patients with acute kidney injury treated by CVVH and RCA. METHODS: A retrospective-comparative study design was applied. Patients who underwent CVVH with RCA in the ICU between 09/2016 and 11/2017 were evaluated. Data were available from the clinical routine. A switch of the replacement fluid Phoxilium® (30 mmol/l HCO3-) to Biphozyl® (22 mmol/l HCO3-) was performed as blood HCO3- concentration persisted ≥ 26 mmol/l despite adjustments of citrate dose and blood flow. Data were collected from 72 h before the switch of the replacement solutions until 72 h afterwards. RESULTS: Of 153 patients treated with CVVH during that period, 45 patients were switched from Phoxilium® to Biphozyl®. Forty-two patients (42 circuits) were available for statistical analysis. After switching the replacement fluid from Phoxilium® to Biphozyl® the serum HCO3- concentration decreased significantly from 27.7 mmol/l (IQR 26.9-28.9) to 25.8 mmol/l (IQR 24.6-27.7) within 24 h (p < 0.001). Base excess (BE) decreased significantly from 4.0 mmol/l (IQR 3.1-5.1) to 1.8 mmol/l (IQR 0.2-3.4) within 24 h (p < 0.001). HCO3- and BE concentration remained stable from 24 h till the end of observation at 72 h after the replacement fluid change (p = 0.225). pH and PaCO2 did not change significantly after the switch of the replacement fluid until 72 h. CONCLUSIONS: This retrospective analysis suggests that for patients developing refractory metabolic alkalosis during CVVH with RCA the use of Biphozyl® reduces external HCO3- load and sustainably corrects intracorporeal HCO3- and BE concentrations. Future studies have to prove whether correcting metabolic alkalosis during CVVH with RCA in critically ill patients is of relevance in terms of clinical outcome.

Impaired fibrinolysis in critically ill COVID-19 patients.

BACKGROUND: Critically ill coronavirus disease 2019 (COVID-19) patients present with a hypercoagulable state with high rates of macrovascular and microvascular thrombosis, for which hypofibrinolysis might be an important contributing factor. METHODS: We retrospectively analysed 20 critically ill COVID-19 patients at Innsbruck Medical University Hospital whose coagulation function was tested with ClotPro® and compared with that of 60 healthy individuals at Augsburg University Clinic. ClotPro is a viscoelastic whole blood coagulation testing device. It includes the TPA test, which uses tissue factor (TF)-activated whole blood with added recombinant tissue-derived plasminogen activator (r-tPA) to induce fibrinolysis. For this purpose, the lysis time (LT) is measured as the time from when maximum clot firmness (MCF) is reached until MCF falls by 50%. We compared COVID-19 patients with prolonged LT in the TPA test and those with normal LT. RESULTS: Critically ill COVID-19 patients showed hypercoagulability in ClotPro assays. MCF was higher in the EX test (TF-activated assay), IN test (ellagic acid-activated assay), and FIB test (functional fibrinogen assay) with decreased maximum lysis (ML) in the EX test (hypofibrinolysis) and highly prolonged TPA test LT (decreased fibrinolytic response), as compared with healthy persons. COVID-19 patients with decreased fibrinolytic response showed higher fibrinogen levels, higher thrombocyte count, higher C-reactive protein levels, and decreased ML in the EX test and IN test. CONCLUSION: Critically ill COVID-19 patients have impaired fibrinolysis. This hypofibrinolytic state could be at least partially dependent on a decreased fibrinolytic response.

Structured ICU resource management in a pandemic is associated with favorable outcome in critically ill COVID­19 patients.

INTRODUCTION: On February 25, 2020, the first 2 patients were tested positive for severe acute respiratory syndrome coronavirus­2 (SARS-CoV-2) in Tyrol, Austria. Rapid measures were taken to ensure adequate intensive care unit (ICU) preparedness for a surge of critically ill coronavirus disease-2019 (COVID-19) patients. METHODS: This cohort study included all COVID-19 patients admitted to an ICU with confirmed or strongly suspected COVID-19 in the State of Tyrol, Austria. Patients were recorded in the Tyrolean COVID-19 intensive care registry. Date of final follow-up was July 17, 2020. RESULTS: A total of 106 critically ill patients with COVID-19 were admitted to 1 of 13 ICUs in Tyrol from March 9 to July 17, 2020. Median age was 64 years (interquartile range, IQR 54-74 years) and the majority of patients were male (76 patients, 71.7%). Median simplified acute physiology score III (SAPS III) was 56 points (IQR 49-64 points). The median duration from appearance of first symptoms to ICU admission was 8 days (IQR 5-11 days). Invasive mechanical ventilation was required in 72 patients (67.9%) and 6 patients (5.6%) required extracorporeal membrane oxygenation treatment. Renal replacement therapy was necessary in 21 patients (19.8%). Median ICU length of stay (LOS) was 18 days (IQR 5-31 days), median hospital LOS was 27 days (IQR 13-49 days). The ICU mortality was 21.7% (23 patients), hospital mortality was 22.6%. There was no significant difference in ICU mortality in patients receiving invasive mechanical ventilation and in those not receiving it (18.1% vs. 29.4%, p = 0.284). As of July 17th, 2020, two patients are still hospitalized, one in an ICU, one on a general ward. CONCLUSION: Critically ill COVID-19 patients in Tyrol showed high severity of disease often requiring complex treatment with increased lengths of ICU and hospital stay. Nevertheless, the mortality was found to be remarkably low, which may be attributed to our adaptive surge response providing sufficient ICU resources.

Lung-kidney interactions in critically ill patients: consensus report of the Acute Disease Quality Initiative (ADQI) 21 Workgroup.

BACKGROUND: Multi-organ dysfunction in critical illness is common and frequently involves the lungs and kidneys, often requiring organ support such as invasive mechanical ventilation (IMV), renal replacement therapy (RRT) and/or extracorporeal membrane oxygenation (ECMO). METHODS: A consensus conference on the spectrum of lung-kidney interactions in critical illness was held under the auspices of the Acute Disease Quality Initiative (ADQI) in Innsbruck, Austria, in June 2018. Through review and critical appraisal of the available evidence, the current state of research, and both clinical and research recommendations were described on the following topics: epidemiology, pathophysiology and strategies to mitigate pulmonary dysfunction among patients with acute kidney injury and/or kidney dysfunction among patients with acute respiratory failure/acute respiratory distress syndrome. Furthermore, emphasis was put on patients receiving organ support (RRT, IMV and/or ECMO) and its impact on lung and kidney function. CONCLUSION: The ADQI 21 conference found significant knowledge gaps about organ crosstalk between lung and kidney and its relevance for critically ill patients. Lung protective ventilation, conservative fluid management and early recognition and treatment of pulmonary infections were the only clinical recommendations with higher quality of evidence. Recommendations for research were formulated, targeting lung-kidney interactions to improve care processes and outcomes in critical illness.

Oliguria in critically ill patients: a narrative review.

Oliguria is often observed in critically ill patients. However, different thresholds in urine output (UO) have raised discussion as to the clinical importance of a transiently reduced UO of less than 0.5 ml/kg/h lasting for at least 6 h. While some studies have demonstrated that isolated oliguria without a concomitant increase in serum creatinine is associated with higher mortality rates, different underlying pathophysiological mechanisms suggest varied clinical importance of reduced UO, as some episodes of oliguria may be fully reversible. We aim to explore the clinical relevance of oliguria in critically ill patients and propose a clinical pathway for the diagnostic and therapeutic management of an oliguric, critically ill patient.

Biomarkers for prediction of renal replacement therapy in acute kidney injury: a systematic review and meta-analysis.

PURPOSE: Acute kidney injury (AKI) frequently occurs in critically ill patients and often precipitates use of renal replacement therapy (RRT). However, the ideal circumstances for whether and when to start RRT remain unclear. We performed evidence synthesis of the available literature to evaluate the value of biomarkers to predict receipt of RRT for AKI. METHODS: We conducted a PRISMA-guided systematic review and meta-analysis including all trials evaluating biomarker performance for prediction of RRT in AKI. A systematic search was applied in MEDLINE, Embase, and CENTRAL databases from inception to September 2017. All studies reporting an area under the curve (AUC) for a biomarker to predict initiation of RRT were included. RESULTS: Sixty-three studies comprising 15,928 critically ill patients (median per study 122.5 [31-1439]) met eligibility. Forty-one studies evaluating 13 different biomarkers were included. Of these biomarkers, neutrophil gelatinase-associated lipocalin (NGAL) had the largest body of evidence. The pooled AUCs for urine and blood NGAL were 0.720 (95% CI 0.638-0.803) and 0.755 (0.706-0.803), respectively. Blood creatinine and cystatin C had pooled AUCs of 0.764 (0.732-0.796) and 0.768 (0.729-0.807), respectively. For urine biomarkers, interleukin-18, cystatin C, and the product of tissue inhibitor of metalloproteinase-2 and insulin growth factor binding protein-7 showed pooled AUCs of 0.668 (0.606-0.729), 0.722 (0.575-0.868), and 0.857 (0.789-0.925), respectively. CONCLUSION: Though several biomarkers showed promise and reasonable prediction of RRT use for critically ill patients with AKI, the strength of evidence currently precludes their routine use to guide decision-making on when to initiate RRT.