Pre-operative assessment

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

The goal of medical preoperative clearance is to assess medical problems in the patients to identify unrecognized co-morbid diseases and optimize preoperative medical condition, also the preoperative medical assessment helps the doctors to decide if the patient is suitable for the proposed surgery according to the patient's risk category, and identify the factors that may reduce the patient risk and provide recommendations for post-operative care. Preoperative clearance usually starts by identifying the type of surgery to be performed and the risk category of the patient who need this surgery.

Perioperative risk of death

Patients can be divided into different risk categories based on the basis of their preoperative medical assessment. this helps the doctors to decide if the patient is suitable for the proposed surgery or procedure, and identify the factors that may reduce the patient risk. There are many factors that may influence the patient risk of complications, including death.

• Anesthesia

Although the modern anesthesia is safe the risk varies according to the type of Anesthesia (general or regional anesthesia). Patient and surgical factors are more important risk predictors.

The American society of anesthesiologists (ASA) Classification is a predictor of preoperative mortality. It also predicts cardiac and pulmonary morbidity.

ASA classification

Class	Systemic disturbance	Mortality
1	Healthy patient with no disease outside of the surgical process	<0.03%
2	Mild-to-moderate systemic disease caused by the surgical condition or by other pathologic processes	0.2%
3	Severe disease process which limits activity but is not incapacitating	1.2%
4	Severe incapacitating disease process that is a constant threat to life	8%
5	Moribund patient not expected to survive 24 hours with or without an operation	34%
E	Suffix to indicate an emergency surgery for any class	Increased

• Type of procedure or surgery

• Patient age

• Emergency procedure

• Pulmonary factors

• Cardiac factors

Scoring systems for perioperative risk

General factors

Cardiac Risk Stratification for Noncardiac Surgical Procedures

High (Reported cardiac risk often greater than 5%)

• Emergent major operations, particularly in the elderly
• Aortic and other major vascular surgery
• Peripheral vascular surgery
• Anticipated prolonged surgical procedures associated with large fluid shifts and/or blood loss

Intermediate (Reported cardiac risk generally less than 5%)

• Carotid endarterectomy
• Head and neck surgery
• Intraperitoneal and intrathoracic surgery
• Orthopedic surgery
• Prostate surgery

Low (Reported cardiac risk generally less than 1%)

• Endoscopic procedures
• Superficial procedure
• Cataract surgery
• Breast surgery

Estimated Energy Requirements for Various Activities

1 MET Can you take care of yourself? 4 METs Climb a flight of stairs or walk up a hill? Eat, dress, or use the toilet? Walk on level ground at 4 mph or 6.4 km per h? Walk indoors around the house? Run a short distance? Walk a block or two on level ground at 2 to 3 mph or 3.2 to 4.8 km per h? Do heavy work around the house like scrubbing floors or lifting or moving heavy furniture? Participate in moderate recreational activities like golf, bowling, dancing, doubles tennis, or throwing a baseball or football? 4 METs Do light work around the house like dusting or washing dishes? Greater than 10 METs Participate in strenuous sports like swimming, singles tennis, football, basketball, or skiing? MET indicates metabolic equivalent.Adapted from the Duke Activity Status Index and AHA Exercise Standards.

Stepwise approach to preoperative cardiac assessment

Sources

http://www.askdrwiki.com/mediawiki/index.php?title=Preoperative_Clearance

References

1. Eagle, K. A. et al. Circulation 2002;105:1257-1267
2. Hlatky MA, Boineau RE, Higginbotham MB, et al. A brief self-administered questionnaire to determine functional capacity (the Duke Activity Status Index). Am J Cardiol. 1989; 64: 651–4