ASA score

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ASA stands for American Society of Anesthesiologists. In 1963 the ASA adopted a five category physical status classification system for assessing a patient before surgery. A sixth category was later added. These are:

1. A normal healthy patient.
2. A patient with mild systemic disease.
3. A patient with severe systemic disease.
4. A patient with severe systemic disease that is a constant threat to life.
5. A moribund patient who is not expected to survive without the operation.
6. A declared brain-dead patient whose organs are being removed for donor purposes.

If the surgery is an emergency, the physical status score is followed by “E” (for emergency) for example “3E”. Category 5 is always an emergency so should not be written without "E". The category 6E probably does not exist. The original definition of emergency in 1940, when ASA classification was first designed, was "a surgical procedure which, in the surgeon's opinion, should be performed without delay."^[1] This gives an opportunity for a surgeon to manipulate the schedule of elective surgery cases for personal convenience. An emergency is therefore now defined as existing when delay in treatment would significantly increase the threat to the patient's life or body part.^[2] With this definition, severe pain due to broken bones, ureteric stone or parturition (giving birth) is urgent, but not an emergency requiring cancellation or aborting of other surgeries.

Contents 1 Limitations and proposed modifications 2 Uses 3 History 4 Other health scoring systems 5 See also 6 References 7 External links

[edit] Limitations and proposed modifications

These definitions appear in each annual edition of the ASA Relative Value Guide. There is no additional information that can be helpful to further define these categories.^[3] It is logical to expect a missing category between ASA 2 and ASA 3 for a systemic disease which is neither mild nor severe, but is of moderate nature. It is also not clear what will be the ASA score of a patient who is suffering simultaneously from two, three or more systemic diseases (which might be of different severity).

Different authors give different versions of this ASA definition.^[4] It is because this classification is vague and far from perfect. Many authors try to explain it on the basis of 'functional limitation' or 'anxiety' of patient which are not mentioned in the actual definition. Often different anesthesia providers assign different scores to the same patient.^[5][6][7][8] The word 'systemic' in this classification creates a lot of confusion. For example, heart attack (myocardial infarction), though grave, is a 'local' disease and is not a 'systemic' disease, so a patient with recent (or old) heart attack, in the absence of any other systemic disease, does not truly fit in any category of the ASA classification, yet has poor post-surgery survival rates. Similarly cirrhosis of the liver, COPD, severe asthma, peri-nephric abscess, badly infected wounds, intestinal perforation, skull fracture etc. are not systemic diseases. These, and other severe heart, liver, lung, intestinal or kidney diseases, although they greatly affect physical status of patient and risk for poor outcomes, cannot be labelled as “systemic disease” (which means a generalized disorder of the whole body like hypertension or diabetes mellitus). Local diseases can also change physical status but has not been mentioned in ASA classification.

This scoring system assumes that age of the patient has no relation to physical fitness, which is not true. Neonates and the elderly, even in the absence of any systemic disease, tolerate otherwise similar anesthetics poorly in comparison to young adults. Similarly this classification ignores patients with malignancy (cancer). This scoring system could not be improved to a more elaborated and scientific form, probably because it is often used for price reimbursement.

Although more complex scoring systems like APACHE II exists [1] they are time-consuming to calculate, and do not have the same utility for ease of communication between surgeons, anesthetists, and insurers.

Some anesthetists now propose that like an 'E' modifier for emergency, a 'P' modifier for pregnancy should be added to the ASA score.^[9]

[edit] Uses

While anesthesia providers use this scale to indicate the patient's overall physical health or "sickness" preoperatively, it is regarded by hospitals, law firms, accrediting boards and other health care groups as a scale to predict risk,^[10] and thus decide if a patient should have – or should have had – an operation.^[11] To predict operative risk, age and obesity of the patient, the nature and severity of the operative procedure, selection of anesthetic techniques, the competency of the surgical team (surgeon, anesthesia providers and assisting staff), duration of surgery or anesthesia, availability of equipment, medicine, blood, implants and especially the level of post-operative care etc. are often far more important than simple ASA score.

[edit] History

In 1940-41, ASA asked a committee of three physicians (Meyer Saklad, M.D., Emery Rovenstine, M.D., and Ivan Taylor, M.D.) to study, examine, experiment and devise a system for the collection and tabulation of statistical data in anesthesia which could be applicable under any circumstances.^[1] This effort was the first by any medical specialty to stratify risk for its patients.^[12] While their mission was to determine predictors for operative risk, they quickly dismissed this task as being impossible to devise. They state:

"In attempting to standardize and define what has heretofore been considered 'Operative Risk', it was found that the term ... could not be used. It was felt that for the purposes of the anesthesia record and for any future evaluation of anesthetic agents or surgical procedures, it would be best to classify and grade the patient in relation to his physical status only."^[11]

The scale they proposed addressed the patient's preoperative state only, not the surgical procedure or other factors that could influence surgical outcome. They hoped anesthesiologists from all parts of the country would adopt their "common terminology," making statistical comparisons of morbidity and mortality possible by comparing outcomes to "the operative procedure and the patient's preoperative condition".^[1][13]

They described a six-point scale, ranging from a healthy patient (class 1) to one with an extreme systemic disorder that is an imminent threat to life (class4). The first four points of their scale roughly correspond to today's ASA classes 1-4, which were first published in 1963.^[5] The original authors included two classes that encompassed emergencies which otherwise would have been coded in either the first two classes (class 5) or the second two (class 6). By the time of the 1963 publication of the present classification, two modifications were made. First, previous classes 5 and 6 were removed and a new class 5 was added for moribund patients not expected to survive 24 hours, with or without surgery. Second, separate classes for emergencies were eliminated in lieu of the "E" modifier of the other classes.^[14][13] The sixth class is now used for declared brain-dead organ donors. Saklad gave examples of each class of patient in an attempt to encourage uniformity. Unfortunately, the ASA did not later describe each category with examples of patients and thus actually increased confusion.

[edit] Other health scoring systems

• APACHE II
• Apgar score
• Barnes Akathisia Scale
• Blantyre Coma Scale
• Dolorimeter pain index
• Glasgow Coma Scale for central nervous system
• Goldman index
• Hamilton-Norwood scale
• Hoehn and Yahr scale
• Holmes and Rahe stress scale
• International Red Cross Wound Classification System
• Life-Events and Difficulties Schedule
• Ludwig scale
• Malinas score
• Paediatric Glasgow Coma Scale
• Pain scale
• PIM2 Children scoring system
• Psoriasis Area Severity Index
• Rancho Los Amigos Scale
• Revised Trauma Score
• SAPS II
• SAPS III
• SOFA score
• Tanner stage
• Tygerberg score

[edit] See also

• Anesthesia
• Anesthesiologist
• Anesthetic equipment
• Anesthetics
• BIS monitor to assess the depth of anaesthesia
• Nurse anesthetist or Certified Registered Nurse Anesthetist (CRNA)
• Perioperative mortality
• Patient safety
• Patient safety organization
• Medical algorithm

[edit] References

[edit] External links

• American Society of Anesthesiologists
• "Women Presenting in Labor Should be Classified as ASA E"
• "Women Presenting in Labor Should NOT be Classified as ASA E"
• "Is it true that ASA 1 excludes the very young and very old?"
• "Anesthesia History Files"