Stratifying risk outcomes among adult COVID-19 inpatients with high flow oxygen: The R4 score.

BACKGROUND: High flow oxygen therapy (HFO) is a widely used intervention for pulmonary complications. Amid the coronavirus infectious disease 2019 (COVID-19) pandemic, HFO became a popular alternative to conventional oxygen supplementation therapies. Risk stratification tools have been repurposed -and new ones developed- to estimate outcome risks among COVID-19 patients. This study aims to provide a simple risk stratification system to predict invasive mechanical ventilation (IMV) or death among COVID-19 inpatients on HFO. METHODS: Among 529 adult inpatients with COVID-19 pneumonia, we selected unadjusted clinical risk factors for developing the composite endpoint of IMV or death. The risk for the primary outcome by each category was estimated using a Cox proportional hazards model. Bootstrapping was used to validate the results. RESULTS: Age above 62, eGFR under 60 ml/min, room air SpO2 ≤89 % upon admission, history of hypertension, history of diabetes, and any comorbidity (cancer, cardiovascular disease, COPD/ asthma, hypothyroidism, or autoimmune disease) were considered for the score. Each of the six criteria scored 1 point. The score was further simplified into 4 categories: 1) 0 criteria, 2) 1 criterion, 3) 2-3 criteria, and 4) ≥4 criteria. Taking the first category as the reference, risk estimates for the primary endpoint were HR; 2.94 [1.67 - 5.26], 4.08 [2.63 - 7.05], and 6.63 [3.74 - 11.77], respectively. In ROC analysis, the AUC for the model was 0.72. CONCLUSIONS: Our score uses simple criteria to estimate the risk for IMV or death among COVID-19 inpatients with HFO. Higher category reflects consistent increases in risk for the endpoint.

Hydrogen sensing in titanate nanotubes associated with modulation in protonic conduction.

Hydrogen/sodium titanate nanotubes (TNTs) were investigated as hydrogen (H(2)) sensors. TNT films exhibit good sensing properties and a large response, in particular at room temperature. Electrical conductivity measurements performed under different atmospheres from 25 to 300 °C indicate that, for T > 100 °C, conduction is thermally activated and can be attributed to electronic transport, whereas for T < 100 °C conduction is dominated by protonic transport. The T dependence of the H(2) sensitivity was determined and related to this variation in the dominant transport mechanism. For low T, H(2) sensing originates from the modulation in protonic conduction. Such modulation was attributed to the creation/destruction of surface hydroxyl groups.