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.

Repeated premature hemofilter clotting during regional citrate anticoagulation as indicator of heparin induced thrombocytopenia.

PURPOSE: Early clinical signs of heparin induced thrombocytopenia (HIT) are nonspecific and include a sudden drop in the number of platelets as well as formation of arterial and venous thromboses. Regional citrate anticoagulation (RCA) is increasingly used as a very effective modality to prevent filter clotting during renal replacement therapy (RRT). We report the first case where repeated premature filter clotting despite RCA indicated a manifestation of HIT. MATERIALS AND METHODS: A 71-year old woman admitted to the ICU for a compartment syndrome of the leg developed septic shock with acute kidney injury requiring continuous veno-venous hemodialysis (CVVHD). Because of unexpected and repeated premature filter clotting during CVVHD using RCA, HIT was suspected. RESULTS: The diagnosis of HIT was confirmed by the presence of IgG antibodies against heparin and platelet factor (PF) 4 complexes and six points in the 4T score. Discontinuation of heparin administration and initiation of systemic anticoagulation with danaparoid sodium resulted in the normalization of platelet count and hemofilter lifetime. CONCLUSION: RCA does not seem to be sufficient to prevent hemofilter clotting during HIT. Thus, in case of repeated premature filter clotting despite RCA, one should suspect HIT and prompt diagnostic workup as well as a switch to alternative anticoagulation.

[Volume therapy: which preparation for which situation?] / Volumentherapie ­ welches Präparat in welcher Situation?

The most commonly used fluids for volume therapy are crystalloids and colloids. Crystalloids comprise 0.9% sodium chloride and balanced crystalloids (BC). Colloids can be divided into artificial colloids and human albumin (a natural colloid). Large studies show advantages for BC over 0.9% NaCl with respect to renal endpoints, probably due to the unphysiologically high chloride content of 0.9% NaCl. However, other studies, such as the BaSICS and PLUS trials, showed no significant differences in mortality in a heterogeneous population. Despite this, meta-analyses suggest advantages for BC. Therefore, BC should be preferred, especially in patients at increased risk of acute kidney injury, with acidemia and/or hyperchloremia. Except for specific indications (e.g., in patients with cirrhosis, sepsis resuscitation after initial volume therapy with BC), albumin should not be used. There is clear evidence of harm from hydroxyethyl starch in intensive care patients.

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.

From persistence to palliation: limiting active treatment in the ICU.

PURPOSE OF REVIEW: End-of-life care and communication deficits are important sources of conflicts within ICU teams and with patients or families. This narrative review describes recent studies on how to improve palliative care and surrogate decision-making in ICUs and compares the results with previously published literature on this topic. RECENT FINDINGS: Awareness and use of end-of-life recommendations is still low. Education about end-of-life is beneficial for end-of-life decisions. Residency and nurses training programmes start to integrate palliative care education in critical care. Integration of palliative care consults is recommended and probably cost-effective. Projects that promote direct contact of care team members with patients/families may be more likely to improve care than educational interventions for caregivers only. The family's response to critical illness includes adverse psychological outcome ('postintensive care syndrome-family'). Information brochures and structured communication protocols are likely to improve engagement of family members in surrogate decision-making; however, validation of outcome effects of their use is needed. SUMMARY: Optimizing palliative care and communication skills is the current challenge in ICU end-of-life care. Intervention strategies should be interdisciplinary, multiprofessional and family-centred in order to quickly reach these goals.

Differential procoagulatory response of microvascular, arterial and venous endothelial cells upon inflammation in vitro.

INTRODUCTION: Inflammation induces a procoagulant phenotype of endothelial cells (EC) with the exposure of tissue factor (TF), a potent initiator of the extrinsic coagulation cascade. Although systemic inflammation affects the whole vascular system, thrombotic lesions occur particularly in microcirculation. This raises the question of whether TF-procoagulant activity (TF-PCA) differs between EC from arterial, venous, and microvascular beds. MATERIALS AND METHODS: Functional coagulation tests, including TF-PCA, and inflammatory responses were investigated on arterial, venous and microvascular endothelial cells. Interleukin-6 (IL-6) and TF-levels were determined in cohort of 59 septic patients. RESULTS: We found that tumor necrosis factor alpha (TNFα), lipopolysaccharide, and interleukin-1ß induce a solid, dose-dependent increase in TF-PCA, which is highest in microvascular EC. A positive correlation of interleukin-6 (IL-6) with TF levels was observed in a cohort of 59 septic patients. In contrast, TF-PCA was independent of IL-6 concentrations in vitro. Re-analysis of publicly available gene expression data revealed that among the top 50 genes annotated to coagulation, TF is one of three regulated genes common to the three investigated EC subtypes. The response to inflammatory stimuli in terms of exposure of leukocyte-endothelial- and platelet-endothelial adhesion molecules (E-selectin and PECAM-1), remodeling of adherens junctions, co-exposure of negatively charged surfaces nor breakdown of the glycocalyx was comparable between the EC subtypes and did not explain the higher TF-PCA on microvascular cells. We found that the ratio of TF and TFPI exposure on the endothelial membrane significantly differs between the EC subtypes. CONCLUSIONS: These findings indicate that the ratio of TF to its inhibitor TFPI is a determinant of endothelial TF-PCA, which is most pronounced on microvascular endothelial cells and might explain why the microvascular system is particularly susceptible to inflammation-induced thrombosis.

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.

Linkage of alterations in systemic iron homeostasis to patients' outcome in sepsis: a prospective study.

BACKGROUND: Sepsis, a dysregulated host response following infection, is associated with massive immune activation and high mortality rates. There is still a need to define further risk factors and laboratory parameters predicting the clinical course. Iron metabolism is regulated by both, the body's iron status and the immune response. Iron itself is required for erythropoiesis but also for many cellular and metabolic functions. Moreover, iron availability is a critical determinant in infections because it is an essential nutrient for most microbes but also impacts on immune function and intravascular oxidative stress. Herein, we used a prospective study design to investigate the putative impact of serum iron parameters on the outcome of sepsis. METHODS: Serum markers of iron metabolism were measured in a prospective cohort of 61 patients (37 males, 24 females) with sepsis defined by Sepsis-3 criteria in a medical intensive care unit (ICU) and compared between survivors and non-survivors. Regulation of iron parameters in patients stratified by focus of infection and co-medication as well as association of the markers with sepsis severity scores and survival were investigated with linear and logistic regression corrected for sex and age effects. RESULTS: Positive correlations of increased serum iron and ferritin concentrations upon ICU admission with the severity of organ failure (SOFA score) and with mortality were observed. Moreover, high TF-Sat, elevated ferritin and serum iron levels and low transferrin concentrations were associated with reduced survival. A logistic regression model consisting of SOFA and transferrin saturation (SOFA-TF-Sat) had the best predictive power for survival in septic ICU patients. Of note, administration of blood transfusions prior to ICU admission resulted in increased TF-Sat and reduced survival of septic patients. CONCLUSIONS: Our study could show an important impact of serum iron parameters on the outcome of sepsis. Furthermore, we identified transferrin saturation as a stand-alone predictor of sepsis survival and as a parameter of iron metabolism which may in a combined model improve the prediction power of the SOFA score. TRIAL REGISTRATION: The study was carried out in accordance with the recommendations of the Declaration of Helsinki on biomedical research. The study was approved by the institutional ethics review board of the Medical University Innsbruck (study AN2013-0006).

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.

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.

Oliguria and Biomarkers of Acute Kidney Injury: Star Struck Lovers or Strangers in the Night?

Oliguria is a common phenomenon that is found in hospitalized patients . Although a rapid reduction in urine excretion rate may reflect a precipitous fall in the glomerular filtration rate, in many cases it may not. Given the common physiological finding of oliguria, we explore the relationship between the functional biomarker of renal injury (oliguria) with the increasing number of markers of renal injury to see if this combination may aid in risk stratification. © 2016 S. Karger AG, Basel.