Acute Physiology and Chronic Health Evaluation Apache Ii Calculator
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Reviewed by Calculator Editorial Team
The Acute Physiology and Chronic Health Evaluation II (APACHE II) is a widely used scoring system in intensive care units to assess patient severity and predict mortality risk. This calculator helps healthcare professionals quickly evaluate patients based on physiological variables and chronic health factors.
What is APACHE II?
The APACHE II system was developed in 1985 as an improvement over the original APACHE system. It evaluates patients based on 12 physiological variables and 7 chronic health factors, providing a more comprehensive assessment of patient status.
The APACHE II score ranges from 0 to 71, with higher scores indicating more severe illness. Scores are typically used to predict mortality risk, guide treatment decisions, and monitor patient progress.
Key Components
The APACHE II score consists of two main components:
- Acute Physiology Score (APS): Evaluates current physiological status (8 variables)
- Chronic Health Evaluation (CHE): Assesses baseline health status (7 variables)
Variables Included
The system considers both acute and chronic factors:
How to Use This Calculator
To use the APACHE II calculator, you'll need to input values for each of the 19 variables. The calculator will then compute the Acute Physiology Score (APS) and Chronic Health Evaluation (CHE) components, and combine them to produce the final APACHE II score.
Step-by-Step Guide
- Enter patient's age in years
- Select chronic health factors (yes/no) where applicable
- Input current physiological measurements
- Click "Calculate" to generate the score
- Review the results and interpretation
Example Calculation
Consider a 65-year-old patient with:
- Chronic renal failure: Yes
- Temperature: 37.5°C
- Mean arterial pressure: 80 mmHg
- Heart rate: 110 bpm
- Respiratory rate: 24 breaths/min
- FiO2: 0.21
- PaCO2: 45 mmHg
- Serum sodium: 135 mEq/L
- Serum potassium: 4.5 mEq/L
- Serum creatinine: 1.8 mg/dL
- Hematocrit: 32%
- White blood cell count: 12,000/mm³
- Glasgow Coma Scale: 12
The calculator would compute an APACHE II score of 22, indicating moderate severity.
Interpreting Results
The APACHE II score provides valuable information about patient severity and mortality risk. Here's how to interpret the results:
| APACHE II Score | Severity Level | Approximate Mortality Risk |
|---|---|---|
| 0-10 | Mild | 1-5% |
| 11-20 | Moderate | 5-15% |
| 21-30 | Severe | 15-30% |
| 31-40 | Very Severe | 30-50% |
| 41+ | Extremely Severe | 50%+ |
Scores above 25 generally indicate patients who would benefit from intensive care interventions. The score can also help monitor patient progress over time by comparing scores at different points in the patient's hospitalization.
Limitations
While the APACHE II system is widely used, it has several limitations:
- Does not account for all possible patient factors
- Mortality predictions may vary by patient population
- Score changes may not always reflect clinical improvement
- Requires accurate data input for reliable results
The APACHE II score should be used as one of many tools in patient assessment, not as the sole determinant of care. Clinical judgment should always be the primary consideration.
Frequently Asked Questions
What is the difference between APACHE II and APACHE III?
APACHE III is a more recent version that includes additional variables and has been shown to provide more accurate mortality predictions. However, APACHE II remains widely used in many healthcare settings.
How often should I recalculate the APACHE II score?
The score should be recalculated whenever there are significant changes in the patient's physiological status or when clinical decisions need to be made regarding treatment adjustments.
Can I use APACHE II for all types of ICU patients?
APACHE II is designed for adult patients in intensive care units. It may not be appropriate for pediatric patients or those in other types of critical care settings.
How do I handle missing data points?
For variables that cannot be measured, use the closest available estimate or consult with clinical staff to determine the most appropriate value to use.