APACHE II Score

Predicts hospital mortality in ICU based on patient data and health conditions.

This APACHE II Score predicts hospital mortality in ICU based on physiological patient data and chronic health conditions.

The Acute Physiology and Chronic Health Evaluation II (APACHE II) is one of the ICU scoring systems that classify disease outcome in hospitalized patients.

This calculator consists of two different versions of the APACHE II model to answer to specialist preferences.

The first tab from the APACHE II score calculator requires the direct input of clinical data whilst the second tab allows the selection of the intervals in which the patient belongs. The second tab has the advantage of showing the number of points each interval is awarded.

The variables used in both calculation methods are:

■ Chronic health conditions and/ or severe organ system insufficiency or is immunocompromised and the following conditions:

1) Cirrhosis of the liver – biopsy confirmed or portal hypertension or previous history of hepatic failure/encephalopathy/coma.

2) New York Heart Association Class IV cardiovascular disease.

3) Severe COPD -- Hypercapnia, home O2 use, or pulmonary hypertension, documented chronic hypoxia or respiratory dependency.

4) Renal dialysis.

5) Immunocompromised – through immunosuppression therapy, chemotherapy, radiation, long term steroid medication or autoimmune disease such as lymphoma, AIDS.

■ Age – as mortality risk factor in many comorbidities;

■ Temperature in Fahrenheit or Celsius – body temperature as indicator of infection and general health;

■ pH – is factored in as sign of pulmonary, metabolic acidosis and several other conditions;

■ Mean arterial pressure - measured in mmHg, offers information on blood circulation and possible dysfunctions;

■ Heart rate in beats per minute – the predictive value of resting heart rate;

■ Respiratory rate in breaths per minute – respiration rhythm provides information on the respiratory system;

■ Sodium in mEq/L and Potassium in mEq/L – are determined in order to check the serum balance between Na and K;

■ Acute renal failure (ARF) – is used as risk factor for adverse outcome in critically ill patients with aggravated renal condition;

■ Creatinine in mg/dL – provides information about renal function, glomerular filtration rate and muscular activity;

■ Hematocrit % - evaluates the proportion of red blood cells in the blood sample;

■ White blood cell count in x103/µL – factors in a possible infectious state;

■ A - a gradient if FiO2 ≥0.5 or PaO2 if FiO2 <0.5 – offers information on respiratory function;

■ Glasgow coma scale points – the score obtained here is subtracted from the maximum score (15).

The main limitation of the model is the fact that it can only be used in adults, as it has not been validated in pediatric populations.

The higher the score, the higher the severity of the patient’s status, therefore, the higher the mortality risk.

The following table introduces the non-operative and post-operative mortality risks correlated with APACHE II scores:

APACHE II non op post op

0 - 4 4% 1%

5 - 9 8% 3%

10 - 14 15% 7%

15 - 19 24% 12%

20 - 24 40% 30%

25 - 29 55% 35%

30 - 34 73% 73%

≥35 85% 88%