Assessment of Heart Rate, Acidosis, Consciousness, Oxygenation, and Respiratory Rate Score to Predict Noninvasive Ventilation Failure in Hypoxemic Patients

Abstract Background: Acute hypoxemic respiratory failure (AHRF) is a life-threatening condition frequently managed with noninvasive ventilation (NIV) in intensive care units (ICUs). A significant proportion of patients fails NIV and requires escalation to invasive mechanical ventilation. Delayed recognition of NIV failure is independently associated with increased mortality. Objectives: The objective of this study is to study the clinical profile of patients with hypoxemic respiratory failure, to assess the heart rate, acidosis, consciousness, oxygenation, and respiratory rate (HACOR) score at initiation and at 2 h of NIV, to identify patients at high risk for NIV failure, and to study their outcomes. Materials and Methods: This prospective, observational study enrolled 80 patients with AHRF admitted to a tertiary care medical ICU. The HACOR score was calculated at NIV initiation and at 2 h. Patients with HACOR >5 at 2 h were classified as high risk. NIV outcome and in-hospital mortality were recorded and analyzed using Chi-square and Fisher’s exact tests. Results: The mean age was 56.75 ± 20.4 years with male predominance (62.5%). Bacterial pneumonia was the most common diagnosis. The mean HACOR score decreased from 6.09 ± 3.22 at initiation to 4.40 ± 4.05 at 2 h. Of 80 patients, 36.3% were classified high risk. NIV failure occurred in 41.3%. HACOR score category at 2 h was highly significantly associated with NIV failure ( P < 0.001); all patients with HACOR ≥12 failed NIV. Female sex was significantly associated with NIV failure ( P = 0.037). In-hospital mortality was 35.0%, significantly associated with HACOR score at 2 h ( P = 0.042) and NIV outcome ( P = 0.001), with 67.9% of deaths occurring in the NIV failure group. Conclusion: The HACOR score assessed at 2 h of NIV initiation is a reliable, bedside, noninvasive predictor of NIV failure and in-hospital mortality in AHRF patients. Its routine integration into ICU monitoring protocols is recommended for the timely identification of high-risk patients and early escalation of ventilatory support.