APACHE II ("Acute Physiology and Chronic Health Evaluation II") is a severity-of-disease classification system, one of several ICU scoring systems. It is applied within 24 hours of admission of a patient to an

intensive care unit 220px, Intensive care unit An intensive care unit (ICU), also known as an intensive therapy unit or intensive treatment unit (ITU) or critical care unit (CCU), is a special department of a hospital or health care facility that provides intensi ...

(ICU): an integer score from 0 to 71 is computed based on several measurements; higher scores correspond to more severe disease and a higher risk of death. The first APACHE model was presented by Knaus et al. in 1981.

Application

APACHE II was designed to measure the severity of disease for adult patients admitted to intensive care units. It has not been validated for use in children or young people aged under 16. This scoring system is used in many ways which include: # Some procedures or some medicine is only given to patients with a certain APACHE II score # APACHE II score can be used to describe the morbidity of a patient when comparing the outcome with other patients. # Predicted mortalities are averaged for groups of patients in order to specify the group's morbidity. Even though newer scoring systems, such as APACHE III, have replaced APACHE II in many places, APACHE II continues to be used extensively because so much documentation is based on it.

Calculation

The point score is calculated from 12 admission physiologic variables comprising the Acute Physiology Score, the patient's age, and chronic health status: ; A. Acute Physiology Score (measured within 24 hours of admission) # AaDO2 or

PaO2 Blood gas tension refers to the partial pressure of gases in blood. There are several significant purposes for measuring gas tension. The most common gas tensions measured are oxygen tension (PxO2), carbon dioxide tension (PxCO2) and carbon monox ...

(for FiO2≥0.5 or <0.5, respectively) #

body temperature Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. A thermoconforming organism, by contrast, simply adopts the surrounding temperature ...

(rectal) #

mean arterial pressure In medicine, the mean arterial pressure (MAP) is an average blood pressure in an individual during a single cardiac cycle. MAP is altered by cardiac output and systemic vascular resistance. Testing Mean arterial pressure can be measured dire ...

blood pH Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in the ...

heart rate Heart rate (or pulse rate) is the frequency of the heartbeat measured by the number of contractions (beats) of the heart per minute (bpm). The heart rate can vary according to the body's physical needs, including the need to absorb oxygen and excr ...

respiratory rate The respiratory rate is the rate at which breathing occurs; it is set and controlled by the respiratory center of the brain. A person's respiratory rate is usually measured in breaths per minute. Measurement The respiratory rate in humans is me ...

# serum sodium # serum potassium #

creatinine Creatinine (; ) is a breakdown product of creatine phosphate from muscle and protein metabolism. It is released at a constant rate by the body (depending on muscle mass). Biological relevance Serum creatinine (a blood measurement) is an importa ...

(Double point score for acute renal failure) #

hematocrit The hematocrit () (Ht or HCT), also known by several other names, is the volume percentage (vol%) of red blood cells (RBCs) in blood, measured as part of a blood test. The measurement depends on the number and size of red blood cells. It is norm ...

white blood cell count A complete blood count (CBC), also known as a full blood count (FBC), is a set of medical laboratory tests that provide information about the cells in a person's blood. The CBC indicates the counts of white blood cells, red blood cells and p ...

Glasgow Coma Scale The Glasgow Coma Scale (GCS) is a clinical scale used to reliably measure a person's level of consciousness after a brain injury. The GCS assesses a person based on their ability to perform eye movements, speak, and move their body. These thre ...

(15 minus actual GCS) ; B. Age points ; C. Chronic health points If the patient has a history of severe organ system insufficiency (i.e. liver cirrhosis, portal hypertension, NYHA class IV heart failure, severe respiratory disease, dialysis dependent) or is immunocompromised (i.e. due to chemotherapy, radiation, high dose steroid therapy, or advanced leukemia, lymphoma or AIDS) assign points as follows: :a. for nonoperative or emergency postoperative patients: 5 points :b. for elective postoperative patients: 2 points The method is optimized for manual calculation, by using

integer An integer is the number zero (), a positive natural number (, , , etc.) or a negative integer with a minus sign ( −1, −2, −3, etc.). The negative numbers are the additive inverses of the corresponding positive numbers. In the languag ...

values and limiting the number of options so that data fits on a single-sheet paper form. The score is not recalculated during the stay. It is by definition an admission score. If a patient is discharged from the ICU and subsequently readmitted, a new APACHE II score is calculated. In the original research paper that described the APACHE II score, patient prognosis (specifically, predicted mortality) was computed based on the patient's APACHE II score in combination with the principal diagnosis at admission.

APACHE III

A method to compute a refined score known as APACHE III was published in 1991. The score was validated on the dataset from 17,440 adult medical/surgical intensive care unit (ICU) admissions at 40 US hospitals. The prognostic system of APACHE III has two options: *APACHE III Score : Provides an initial risk classification of severely ill hospitalized patients in defined groups. *APACHE III predictive equation : Adds additional variables to the APACHE III Score including the primary reason for ICU admission (from a reference list of 212 conditions classified according to etiology, major organ involved, and distinction between surgical/medical categories); age, sex, race and preexisting comorbidities; and location prior to ICU admission (operating room, recovery or emergency department, transfer or readmission from another hospital or ICU). When possible, the time between the patient's arrival at the hospital and their ICU admission is recorded. To evaluate the severity of disease 20 physiologic variables are measured, compared to 12 variables for APACHE II. APACHE III scores range from 0 to 299.

APACHE IV

APACHE IV, published in 2006, is the latest version. The model was developed using data from 104 intensive care units (ICUs) in 45 U.S. hospitals and could be recommended to use in U.S. ICUs.

References

External links