Predictor factors for non-invasive mechanical ventilation failure in severe COVID-19 patients in the intensive care unit: a single-center retrospective study.

BACKGROUND: During the COVID-19 pandemia, non-invasive mechanical ventilation (NIV) has been largely applied. Few data are available about predictors of NIV failure in critical COVID-19 patients admitted to ICU. The aim of this study is to analyze clinical and laboratory features able to predict non-invasive ventilation success in avoiding endotracheal intubation. METHODS: A retrospective observational study was performed in our COVID-19 ICU during a 6-month period. Demographic, clinical, laboratory, imaging, and outcome data were extracted from electronic and paper medical records and anonymously collected. RESULTS: Eighty-two severe COVID-19 patients were supported by NIV at ICU admission. The median PaO2/FiO2 ratio was 125 [98.5-177.7]. NIV failed in 44 cases (53%). Patients who experienced NIV failure had a higher Charlson Comorbidity Index (median value 4) compared to those who were dismissed without endotracheal intubation (median 2, p < 0.0001). At Cox regression analysis, the Charlson Comorbidity Index represented a predictive factor related to NIV failure. PaO2/FiO2, CPK, INR, and AT III at ICU admission showed a significant relationship with the outcome, when single variables were adjusted for the Charlson Comorbidity Index. CONCLUSION: The Charlson Comorbidity Index may be helpful to stratify patients' risk of NIV failure in a severe COVID-19 population; even if this study, retrospective design does not allow definitive conclusions.

Krebs von den Lungen 6 (KL-6) levels in COVID-19 ICU patients are associated with mortality.

BACKGROUND: Krebs von den Lungen 6 (KL-6) is a high-molecular-weight mucin-like glycoprotein, which is also known as MUC1. KL-6 is mainly produced by type 2 pneumocytes and bronchial epithelial cells, and, therefore, elevated circulating KL-6 levels may denote disorders of the alveolar epithelial lining. The objective of this study is to verify if KL-6 serum level might support ICU physicians in predicting mortality, risk stratifying and triaging severe COVID-19 patients. METHODS: A retrospective cohort study, including all the COVID-19 patients who measured KL-6 serum values at least once during their ICU stay, was performed. The study sample, 122 patients, was divided in two groups, according to the median KL-6 value at ICU admission (median log-transformed KL-6 value: 6.73 U/ml; group A: KL-6 lower than the median and group B: KL-6 higher than the median). RESULTS: One-hundred twenty-two ICU patients were included in this study. Mortality was higher in group B than in group A (80 versus 46%; p < 0.001); both linear and logistic multivariate analyses showed ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (P/F) significantly and inversely related to KL-6 values. CONCLUSION: At ICU admission, KL-6 serum level was significantly higher in the most hypoxic COVID-19 patients and independently associated with ICU mortality.

Reference Ranges of Left Ventricular Hemodynamic Forces in Healthy Adults: A Speckle-Tracking Echocardiographic Study.

BACKGROUND: The normal limits of left ventricular (LV) hemodynamic forces (HDFs) are not exactly known. The aim of this study was to explore the full spectrum of HDF parameters in healthy subjects and determine their physiologic correlates. METHODS: 269 healthy subjects were enrolled (mean age: 43 ± 14 years; 123 (45.7%) men). All participants underwent an echo-Doppler examination. Tri-plane tissue tracking from apical views was used to measure 2D global endocardial longitudinal strain (GLS), circumferential strain (GCS), and LV HDFs. HDFs were normalized with LV volume and divided by specific weight. RESULTS: LV systolic longitudinal HDFs (%) were higher in men (20.8 ± 6.5 vs. 18.9 ± 5.6, p = 0.009; 22.0 ± 6.7 vs. 19.8 ± 5.6, p = 0.004, respectively). There was a significant correlation between GCS (increased) (r = -0.240, p < 0.001) and LV longitudinal HDFs (reduced) (r = -0.155, p = 0.01) with age. In a multivariable analysis age, BSA, pulse pressure, heart rate and GCS were the only independent variables associated with LV HDFs (ß coefficient = -0.232, p < 0.001; 0.149, p = 0.003; 0.186, p < 0.001; 0.396, p < 0.001; -0.328, p < 0.001; respectively). CONCLUSION: We report on the physiologic range of LV HDFs. Knowledge of reference values of HDFs may prompt their implementation into clinical routine and allow a more comprehensive assessment of the LV function.