Enter Patient Inputs
Use bedside observations, arterial blood gas values, and support details. All fields accept decimal values where appropriate.
Example Data Table
| Case | RR | SpO₂ | FiO₂ | PaO₂ | PaCO₂ | pH | GCS | ROX | HACOR | Example Reading |
|---|---|---|---|---|---|---|---|---|---|---|
| Stable support | 20 | 96 | 28% | 92 | 40 | 7.40 | 15 | 17.14 | 0 | Low concern trend. |
| Borderline hypoxemia | 28 | 93 | 40% | 74 | 46 | 7.35 | 15 | 8.30 | 1 | Needs reassessment. |
| Escalating distress | 34 | 89 | 60% | 66 | 55 | 7.29 | 14 | 4.36 | 13 | High concern pattern. |
| Critical compromise | 40 | 84 | 80% | 58 | 68 | 7.21 | 10 | 2.63 | 24 | Immediate emergency action. |
Formula Used
Core Calculations
ROX Index = (SpO₂ ÷ FiO₂) ÷ Respiratory Rate
P/F Ratio = PaO₂ ÷ FiO₂
Alveolar Oxygen = ((760 − 47) × FiO₂) − (PaCO₂ ÷ 0.8)
A–a Gradient = Alveolar Oxygen − PaO₂
Score Logic
HACOR adds points from heart rate, pH, GCS, P/F ratio, and respiratory rate.
Overall Risk % is a custom educational composite weighting oxygenation, ventilation, acid-base status, neurologic status, age, and comorbidity burden.
How to Use This Calculator
- Enter bedside vitals, blood gas values, and FiO₂ percentage.
- Select the current respiratory support method.
- Submit the form to generate risk scores above it.
- Review the ROX, HACOR, P/F ratio, and A–a gradient together.
- Use the chart and flags to identify the biggest drivers.
- Export the summary as CSV or PDF for documentation.
- Repeat after treatment changes to compare new values.
Important Note
This page is for education, audit support, and structured discussion. It is not a diagnostic device and must not replace emergency assessment, physician judgment, or local protocols.
Frequently Asked Questions
1) What does this calculator estimate?
It estimates respiratory deterioration concern using oxygenation, ventilation, consciousness, and blood gas data. It is best used as a structured educational summary, not a final diagnosis.
2) Why are ROX and HACOR both shown?
They highlight different dimensions. ROX focuses on oxygenation versus breathing effort, while HACOR adds acidosis, consciousness, heart rate, and oxygenation burden.
3) Can I use room-air values?
Yes. Enter FiO₂ as 21 for room air. That allows P/F ratio and ROX calculations without changing the page structure.
4) Is the overall risk percentage validated?
No. The percentage is a custom educational composite. The individual metrics are recognized, but the combined percentage is intentionally presented as a supportive teaching aid.
5) Why include the A–a gradient?
It helps frame oxygen transfer efficiency. When read beside the P/F ratio and ROX, it gives a broader gas-exchange picture.
6) What if some ABG values are unavailable?
For best accuracy, enter complete blood gas data. If unavailable, you can still use the page after entering estimates, but interpret results cautiously.
7) When should results trigger urgent action?
Very low oxygen saturation, worsening mental status, severe acidosis, severe hypercapnia, or rapidly rising oxygen needs all deserve immediate emergency attention.
8) Can I use this for repeat trend checks?
Yes. Re-enter updated values after treatment changes. Trend comparison is often more useful than one isolated reading.