The HACOR score is a validated clinical tool used to predict the likelihood of NIV failure in patients with acute respiratory failure. This score can guide clinicians in identifying patients who are at higher risk of requiring invasive mechanical ventilation, allowing early intervention.
The HACOR score assesses five key parameters:
- Heart rate (H)
- Acidosis (A) (assessed via pH)
- Consciousness (C) (Glasgow Coma Scale, GCS)
- Oxygenation (O) (PaO2/FiO2 ratio)
- Respiratory rate (R)
Each parameter is assigned a score based on severity, and the total score helps determine the likelihood of NIV failure.
HACOR Score Components and Scoring
| Component | 0 Points | 1 Points | 2 Points | 3 Points |
| Heart Rate (beats/min) | <120 | 120-139 | 140-159 | ≥160 |
| Acidosis (pH) | ≥7.35 | 7.30-7.34 | 7.25-7.29 | <7.25 |
| Consciousness (GCS) | 15 | 13-14 | 11-12 | ≤10 |
| Oxygenation (PaO2/FiO2) | ≥200 | 175-199 | 150-174 | <150 |
| Respiratory Rate (breaths/min) | ≤30 | 31-35 | 36-40 | >40 |
Interpreting the HACOR Score
Total Score:
0–5 points:
- Low risk of NIV failure. Continued NIV may be successful.
6–10 points:
- Moderate risk of NIV failure. Close monitoring is essential, and be prepared to escalate therapy if needed.
11–15 points:
- High risk of NIV failure. Strong consideration for intubation and invasive mechanical ventilation.
Predictive Value:
A HACOR score >5 indicates a significant risk of NIV failure. Early decision-making for intubation may be required if the score remains high despite ongoing NIV.
Clinical Use of the HACOR Score
A. Initial Assessment and Monitoring
- Calculate the HACOR score within the first 1–2 hours of starting NIV.
- Use the score to predict early NIV failure, which is critical to avoid delays in transitioning to invasive mechanical ventilation.
B. Decision-Making
HACOR score ≤5:
- Continue NIV, but reassess frequently to ensure improvement.
HACOR score 6–10:
- Reevaluate NIV settings (e.g., increase inspiratory pressure, adjust FiO2). Consider escalating care (e.g., intubation) if the score does not improve.
- HACOR score >10: Strong consideration for intubation, as NIV is likely failing.
C. Serial Monitoring
- Recalculate the HACOR score after adjustments to NIV or with any clinical deterioration.
- Persistently high HACOR scores, especially >5, indicate that NIV may not be sufficient, and early transition to invasive ventilation is advised.