What Is an ASA Score in Surgery?

The ASA (American Society of Anesthesiology) score is a metric to determine if someone is healthy enough to tolerate surgery and anesthesia.

The American Society of Anesthesiologists (ASA) Physical Status Classification System is a tool used in preparation for surgery to help predict risks in a given patient. The system uses a scale based on the patient’s medical history, severity of known medical conditions, and current physical state to help predict if they can tolerate anesthesia and the conditions of surgery. The ASA Physical Status Classification System has been used for more than 60 years, and was updated in 2019 to include additional disease examples. 

The ASA Physical Status Classification System uses a scale from I to VI, with I being a healthy patient with minimal risks, to VI being a brain-dead patient with plans for organ donation. 

In addition to the ASA Physical Status Classification System, other factors should be considered, including age, other illnesses, medications, duration and extent of surgery, choice of anesthesia and medications to be used, surgical team technique, need for blood products, surgical devices needed, and expected postoperative care. 

The definitions and examples listed below are guidelines for the clinician. 

ASA I 

• A normal healthy patient, as follows:
• Healthy 
• Normal body mass index (BMI) 
• Nonsmoker 
• No or minimal alcohol consumption 

ASA II 

• A patient with mild systemic disease without significant functional limitation, as follows:
• Active smoker 
• Social alcohol consumption 
• Pregnancy 
• Obesity - BMI 30-40 
• Controlled diabetes mellitus (DM) and high blood pressure (hypertension)
• Mild lung (pulmonary) dysfunction 

ASA III 

• A patient with severe systemic disease with significant functional limitation, as follows:
• Alcohol dependence or abuse 
• Morbid obesity - BMI of more than 40 
• Poorly controlled DM and hypertension 
• Active hepatitis 
• Implanted pacemaker 
• Moderate reduction of ejection fraction (heart pumping power)
• End-stage renal disease (ESRD), undergoing regular, scheduled dialysis 
• Chronic obstructive pulmonary disease (COPD) 
• Premature infant with a post-conceptual age of less than 60 weeks 
• Heart attack history
• Stroke (cerebrovascular accident, or CVA) or transient ischemic attack (TIA) 
• Coronary artery disease (CAD) with stents 
• Obstructive sleep apnea

ASA IV 

• A patient with severe systemic disease with constant threat to life, as follows:
• Heart attack less than 3 months ago 
• CVA or TIA 
• CAD with stents 
• Ongoing cardiac ischemia or severe valve dysfunction 
• Severe reduction of ejection fraction 
• Sepsis 
• Disseminated intravascular coagulation (DIC) 
• ESRD, not undergoing regular scheduled dialysis 

ASA V 

• A critically ill patient not expected to survive without the operation, as follows:
• Ruptured thoracic or abdominal aneurysm 
• Massive trauma 
• Intracranial bleeding with mass effect 
• Ischemic bowel with significant cardiac pathology 
• Multiple organ or system dysfunction ASA 6: A declared brain-dead patient with plans for organ donation

ASA VI 

• A declared brain-dead patient with plans for organ donation