Free hemoglobin determination at patients' bedside to evaluate hemolysis.

Background: The authors report the relevance of using a point of care test (Helge®) for free hemoglobin determination and concordance of the values the with Cobas® 8000 and spectrophotometer methods. Results: The within-run of the point of care test was <3%. Good correlations among the three methods were observed and an acceptable concordance for hemolysis index values from 50 mg/dl. An excellent agreement between the Cobas 8000 and the spectrophotometer was found. Conclusion: Automated methods represent methods of choice for free hemoglobin determination. An advantage of the Helge system is that it can be applied to samples experiencing a delay in evaluation due to the long distance between the collection site and the central laboratory. Another advantage is its use at the bedside, in the monitoring of extracorporeal membrane oxygenation patients.

[Myocardial injury in coronavirus disease 19 (Covid-19): main pathophysiological mechanisms and clinical utility of cardiac biomarkers]. / Atteintes myocardiques au cours de la maladie à coronavirus 19 (Covid-19) : principaux mécanismes physiopathologiques et utilité clinique des biomarqueurs cardiaques.

Covid-19 is responsible for myocardial injury in many infected patients, which is associated with severe disease and critical illness. The mechanisms by which SARS-CoV-2 may cause myocardial damage involve direct effect of the virus in cardiac cells and indirect effect due to the clinical consequences of Covid-19. Cardiomyocytes are well known to express Angiotensin-Converting Enzyme-2 receptors (ACE-2) to facilitate the virus cell entry, which could explain the occurrence of myocarditis, functional alterations in the myocardium, and more rarely, myocardial infarction. Myocardial injury may also be secondary to systemic inflammation or coagulopathy due to complicated Covid-19. The existence of a cardio-intestinal axis with alteration of tryptophan metabolism in the small bowel leading first to colitis and then to systemic inflammation has also been evoked to explain the myocardial injury. Morphological and metabolic disturbances of the heart during the Covid-19 are associated with elevated concentrations of cardiac blood biomarkers, mainly troponins and natriuretic peptides. The determination of these biomarkers has proven to be very useful for diagnosis, prognosis, and risk stratification. Indeed, recent data demonstrated that about 20% of infected patients admitted to the hospital have elevated troponin or BNP levels, and Covid-19 patients with elevated troponin concentrations beyond the diagnostic threshold (99th percentile) were associated with a higher risk of in-hospital mortality. In conclusion, after more than a year of a unique global pandemic, it is now clearly established that myocardial injury during Covid-19 is frequent and strongly contributes to the severity of the disease. Cardiac alterations secondary to direct infection of cardiac cells by SARS-CoV-2 or to the clinical consequences of Covid-19 are associated with elevated levels of cardiac biomarkers in blood, whose measurement is crucial in clinical decision making.

Admission High-Sensitive Cardiac Troponin T Level Increase Is Independently Associated with Higher Mortality in Critically Ill Patients with COVID-19: A Multicenter Study.

BACKGROUND: In coronavirus disease 2019 (COVID-19) patients, increases in high-sensitive cardiac troponin T (hs-cTnT) have been reported to be associated with worse outcomes. In the critically ill, the prognostic value of hs-cTnT, however, remains to be assessed given that most previous studies have involved a case mix of non- and severely ill COVID-19 patients. METHODS: We conducted, from March to May 2020, in three French intensive care units (ICUs), a multicenter retrospective cohort study to assess in-hospital mortality predictability of hs-cTnT levels in COVID-19 patients. RESULTS: 111 laboratory-confirmed COVID-19 patients (68% of male, median age 67 (58-75) years old) were included. At ICU admission, the median Charlson Index, Simplified Acute Physiology Score II, and PaO2/FiO2 were at 3 (2-5), 37 (27-48), and 140 (98-154), respectively, and the median hs-cTnT serum levels were at 16.0 (10.1-31.9) ng/L. Seventy-five patients (68%) were mechanically ventilated, 41 (37%) were treated with norepinephrine, and 17 (15%) underwent renal replacement therapy. In-hospital mortality was 29% (32/111) and was independently associated with lower PaO2/FiO2 and higher hs-cTnT serum levels. CONCLUSIONS: At ICU admission, besides PaO2/FiO2, hs-cTnT levels may allow early risk stratification and triage in critically ill COVID-19 patients.