American society of anesthesia classification

The ASA physical status classification system is a system for assessing the fitness of patients before surgery. 

The purpose of the system is to assess and communicate a patient’s pre-anesthesia medical co-morbidities. 


Healthy person.

Mild systemic disease.

Severe systemic disease.

Severe systemic disease that is a constant threat to life.

A moribund person who is not expected to survive without the operation.

A declared brain-dead person whose organs are being removed for donor purposes.

It assesses  individual fitness prior to surgery

If the surgery is an emergency, the physical status classification is followed by “E”.

Class 5 is usually an emergency and is therefore usually “5E”. 

The class “6E” does not exist and is simply recorded as class “6”, as all organ retrieval in brain-dead patients is done urgently. 

This classification system assumes that age 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.

For predicting operative risk, other factors: age, presence of comorbidities, the nature and extent of the operative procedure, selection of anesthetic techniques, duration of surgery or anesthesia, availability of equipment, medications, blood, implants and appropriate postoperative care , are often far more important than the ASA physical status.

The classification system alone does not predict the perioperative risks.

When the ASA physical status classification is used with other information: type of surgery, frailty, level of deconditioning it can be helpful in predicting perioperative risks.

The final assignment of Physical Status classification is made on the day of anesthesia care by the anesthesiologist after evaluating the patient.

Current Definitions 

ASA IA normal healthy patientHealthy, non-smoking, no or minimal alcohol use

Healthy (no acute or chronic disease), normal BMI percentile for age  

ASA II A patient with mild systemic disease

Mild diseases only without substantive functional limitations. 

Current smoker, social alcohol drinker, pregnancy, obesity (30<BMI<40), well-controlled DM/HTN, mild lung disease

Asymptomatic congenital cardiac disease, well controlled dysrhythmias, asthma without exacerbation, well controlled epilepsy, non-insulin dependent diabetes mellitus, abnormal BMI percentile for age, mild/moderate OSA, oncologic state in remission, autism with mild limitations, pregnancy, well controlled gestational HTN, controlled preeclampsia without severe features, diet-controlled gestational DM.

ASA IIIA patient with severe systemic disease

Substantive functional limitations; One or more moderate to severe diseases. Poorly controlled DM or HTN, COPD, morbid obesity (BMI ≥40), active hepatitis, alcohol dependence or abuse, implanted pacemaker, moderate reduction of ejection fraction, ESRD undergoing regularly scheduled dialysis, history (>3 months) of MI, CVA, TIA, or CAD/stents.

Uncorrected stable congenital cardiac abnormality, asthma with exacerbation, poorly controlled epilepsy, insulin dependent diabetes mellitus, morbid obesity, malnutrition, severe OSA, oncologic state, renal failure, muscular dystrophy, cystic fibrosis, history of organ transplantation, brain/spinal cord malformation, symptomatic hydrocephalus, premature infant PCA <60 weeks, autism with severe limitations, metabolic disease, difficult airway, long term parenteral nutrition. 

Full term infants <6 weeks of age.

Preeclampsia with severe features, gestational DM with complications or high insulin requirements, a thrombophilic disease requiring anticoagulation.

ASA IV A patient with severe systemic disease that is a constant threat to life Recent (<3 months) MI, CVA, TIA or CAD/stents, ongoing cardiac ischemia or severe valve dysfunction, severe reduction of ejection fraction, shock, sepsis, DIC, ARD or ESRD not undergoing regularly scheduled dialysis, symptomatic congenital cardiac abnormality, congestive heart failure, active sequelae of prematurity, acute hypoxic-ischemic encephalopathy, shock, sepsis, disseminated intravascular coagulation, automatic implantable cardioverter-defibrillator, ventilator dependence, endocrinopathy, severe trauma, severe respiratory distress, advanced oncologic stat, Preeclampsia with severe features complicated by HELLP or other adverse event, peripartum cardiomyopathy with EF <40, uncorrected/decompensated heart disease, acquired or congenital.


A moribund patient who is not expected to survive without the operation-Ruptured abdominal/thoracic aneurysm, massive trauma, intracranial bleed with mass effect, ischemic bowel in the face of significant cardiac pathology or multiple organ/system dysfunctiin, massive trauma, intracranial hemorrhage with mass effect, patient requiring ECMO, respiratory failure or arrest, malignant hypertension, decompensated congestive heart failure, hepatic encephalopathy, ischemic bowel or multiple organ/system dysfunction, uterine rupture.

ASA VI A declared brain-dead patient whose organs are being removed for donor purposes    


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