From the Guidelines
The Acute Physiology and Chronic Health Evaluation (APACHE) II score is a widely used severity of illness scoring system that predicts mortality in critically ill patients, including those in the emergency department.
Application and Calculation
The APACHE II score is calculated based on 12 physiologic parameters and chronic health conditions, making it a comprehensive tool for assessing the severity of illness 1.
- The score takes into account factors such as age, temperature, mean arterial blood pressure, heart rate, respiratory rate, oxygenation, arterial pH, serum sodium, serum potassium, creatinine, hematocrit, and white blood cell count.
- The score also considers chronic health conditions, such as liver disease, cardiovascular disease, and immunocompromised status.
Comparison with Other Scoring Systems
Compared to other scoring systems, such as SOFA and SAPS II, the APACHE II score is preferred for risk stratification in patients with complicated intra-abdominal infections due to its ability to account for age and chronic health conditions 1.
- The APACHE II score has been shown to have high accuracy in predicting mortality in patients with severe acute pancreatitis, with a cutoff value of ≥ 8 1.
Limitations and Considerations
However, the APACHE II score has some limitations, including its cumbersome calculation and the need for routine collection of all parameters 1.
- Additionally, the score may be influenced by lead time bias, where patients who receive excellent pre-ICU care may have a lower score despite having a severe underlying disease 1.
Clinical Use
Despite these limitations, the APACHE II score remains a valuable tool for clinicians in the emergency department to quickly assess the severity of illness and make informed decisions about patient care.
- The score can be used to identify high-risk patients who require close monitoring and aggressive treatment, and to evaluate the effectiveness of interventions 1.
From the Research
Definition and Application of APACHE II Score
- The Acute Physiology and Chronic Health Evaluation (APACHE) II score is a severity of disease classification system that uses a point score based on initial values of 12 routine physiologic measurements, age, and previous health status to provide a general measure of severity of disease 2.
- The APACHE II score is still commonly used as an index of illness severity in patients admitted to the intensive care unit (ICU) and has been validated for many research and clinical audit purposes 3.
Predictive Value of APACHE II Score
- The APACHE II score has been shown to have a high prognostic value for predicting mortality rate in critically ill patients, with an area under the curve of 0.88 3.
- A study found that an APACHE II score of 15 provides the best diagnostic accuracy to predict mortality of critically ill patients, with a sensitivity of 85.3%, a specificity of 77.4%, a positive predictive value of 83.9%, and a negative predictive value of 73.9% 3.
- The APACHE II score has also been validated as a predictor of mortality in COVID-19 patients admitted to the ICU, with a good discriminative power and calibration 4.
Comparison with Other Scoring Systems
- The APACHE II score has been compared to the Glasgow Coma Scale (GCS) for prediction of mortality in head-injured patients with systemic trauma, and was found to be more effective than GCS 5.
- The APACHE II score includes 12 physiological variables, as well as recognition of increasing age and significant chronic health problems, which adversely affect mortality, making it a more comprehensive scoring system than GCS 5.
Application in the Emergency Department
- While the APACHE II score is primarily used in the ICU, its application in the emergency department (ED) can help with early identification of critically ill patients and prediction of mortality risk 6.
- The APACHE II score can be used in the ED to evaluate the severity of illness and prioritize patients for admission to the ICU or for other interventions 6.