Prediction of Mortality With the Use of Noninvasive Ventilation for Acute Respiratory Failure

Background: In actuality, it is difficult to obtain an early prognostic stratification for patients with acute respiratory failure treated with noninvasive ventilation (NIV). We tested whether an early evaluation through a predictive scoring system could identify subjects at risk of in-hospital mortality or NIV failure.

Methods: This was a retrospective study, which included all the subjects with acute respiratory failure who required NIV admitted to an emergency department-high-dependence observation unit between January 2014 and December 2017. The HACOR (heart rate, acidosis [by using pH], consciousness [by using the Glasgow coma scale], oxygenation [by using [Formula: see text]/[Formula: see text]], respiratory rate) score was calculated before the NIV initiation (T0) and after 1 h (T1) and 24 h (T24) of treatment. The primary outcomes were in-hospital mortality and NIV failure, defined as the need for invasive ventilation.

Results: The study population included 644 subjects, 463 with hypercapnic respiratory failure and an overall in-hospital mortality of 23%. Thirty-six percent of all the subjects had NIV as the "ceiling" treatment. At all the evaluations, nonsurvivors had a higher mean ± SD HACOR score than did the survivors (T0, 8.2 ± 4.9 vs 6.1 ± 4.0; T1, 6.6 ± 4.8 vs 3.8 ± 3.4; T24, 5.3 ± 4.5 vs 2.0 ± 2.3 [all P < .001]). These data were confirmed after the exclusion of the subjects who underwent NIV as the ceiling treatment (T0, 8.2 ± 4.9 vs 6.1 ± 4.0 [P = .002]; T1, 6.6 ± 4.8 vs 3.8 ± 3.4; T24, 5.3 ± 4.5 vs 2.0 ± 3.2 [all P < .001]). At T24, an HACOR score > 5 (Relative Risk [RR] 2.39, 95% CI 1.60-3.56) was associated with an increased mortality rate, independent of age and the Sequential Organ Failure Assessment score.

Conclusions: Among the subjects treated with NIV for acute respiratory failure, the HACOR score seemed to be a useful tool to identify those at risk of in-hospital mortality.