Non-Invasive Ventilation (NIV) aims to improve pulmonary ventilation and reverse the reason for ventilatory failure. Despite the benefits, improper use can contribute to failure of ventilatory therapy. NIV failure, which translates into the need for orotracheal intubation, is 30% and mortality in this group is 47%. The HACOR scale was developed using HR, RR, PaO2/FiO2 Ratio, Glasgow, Ph and is intended to predict the risk of NIV failure. The scale should be applied after 1h of NIV use. Its score ranges from 0 to 25 points and the closer to the maximum value, the greater the risk of failure. A score above 5 points indicates a greater than 80% risk of therapy failure. The scale showed 72.6% sensitivity and 90.2% specificity for the diagnosis of NIV failure. Given the importance of having a single scale with adequate accuracy for predicting NIV failure available in the literature and the absence of a Brazilian-Portuguese version that tested the clinimetric properties. It is necessary to test the properties so that with the test results, the scale can be used in Brazilian hospitals.

Test the clinimetric properties of the HACOR scale in adult patients using NIV in a hospital emergency room.

The HACOR scale considers heart rate, acidosis (blood pH), Glasgow scale, oxygenation (PaO2/FiO2) and respiratory rate, from 0 to 25 points. The highest score defines the need for intubation (mechanical ventilation-MV) after one hour of NIV in hypoxemic hospitalized patients. Ten minutes later, the second application of the HACOR scale was performed to test the reliability (Intraclass Correlation Coefficient-ICC), measurement error (standard error of measurement-SME and minimum difference detected-DMD), ceiling and floor effect, validity of construct by correlation (Pearson-r) with pulse oxygen saturation (SpO2) and predictive capacity (area under the ROC-curve).

The HACOR scale considers heart rate, acidosis (blood pH), Glasgow scale, oxygenation (PaO2/FiO2) and respiratory rate, from 0 to 25 points. The highest score defines the need for intubation (mechanical ventilation-MV) after one hour of NIV in hypoxemic hospitalized patients. Ten minutes later, the second application of the HACOR scale was performed to test the reliability (Intraclass Correlation Coefficient-ICC), measurement error (standard error of measurement-SME and minimum difference detected-DMD), ceiling and floor effect, validity of construct by correlation (Pearson-r) with pulse oxygen saturation (SpO2) and predictive capacity (area under the ROC-curve).

The HACOR scale has adequate clinimetric properties, however, it showed a floor effect in the sample included in this study.

The study shows the HACOR scale provides an adequate level of reproducibility within emergency rooms and intensive care units in Brazil. That said, it can be used with greater confidence by Brazilian health professionals during their clinical practice, concretely assisting in the decision of progression to orotracheal intubation and assessment of success of non-invasive ventilation. Besides becoming useful for future studies that will use the scale in Brazil.