1. Three key elements must be assessed to determine a patient's surgical risk: underlying medical conditions and diseases, functional status, and type of surgery.
2. The American Society of Anesthesiologists (ASA) Physical Status classification is commonly used but is limited in only considering medical history and does not include other factors like surgery type. Higher ASA classes correlate with increased postoperative complications and mortality.
3. Other tools like the Goldman Cardiac Risk Index and Revised Cardiac Risk Index were developed to better evaluate cardiac risk, but have limitations and may not predict all-cause mortality risk.
3. Introduction
• In order to assess a patients risk for intraoperative/postoperative
complications an anesthesiologist and/or surgeon must take into account
many aspects. For instance
– Patients Physiological Status (Preop, Intraop, and Postop)
– The disease being modified in Surgery
– The type of Surgery
– The Institute in which one practices
• The 48 h and 30 d incidence of postoperative mortality was 0.57 % and
2.1% respectively. Higher ASA physical status scores, extremes of age,
emergencies, perioperative adverse events and postoperative Intensive
Care Unit admission were identified as risk factors.
• Due to the increasing number of co- morbidities in today’s patients many
new systems have arisen to judge the risk of the surgery to the patient.
4.
5. ASA Physical Status Classification
Table 13-1: American Society of Anesthesiologists Physical Status Classification*
• ASA 1 Healthy patient without organic, biochemical, or psychiatric disease.
Excludes extremes of age.
• ASA 2 A patient with mild systemic disease. No significant impact on daily
activity. Unlikely impact on anesthesia and surgery. Examples: mild asthma, well-
controlled HTN, DM w/o renal disease, cigarette smoking w/o COPD, mild obesity,
pregnancy.
• ASA 3 Significant or severe systemic disease that limits normal activity.
Significant impact on daily activity. Likely impact on anesthesia and surgery.
Examples: stable angina, old MI, controlled CHF, CRF, class 2 CHF.
• ASA 4 Severe disease that is a constant threat to life or requires intensive
therapy. Serious limitation of daily activity. Major impact on anesthesia and
surgery. Examples: end-stage disease, CRF on dialysis, acute MI, respiratory failure
requiring mechanical ventilation.
• ASA 5 Moribund patient who is likely to die in the next 24 hours with or without
surgery.
• ASA 6 Brain-dead organ donor.
* “E” added to the above classifications indicates emergency surgery, Available at
www.asahq.org.
6. “Does ASA Classification Correlate With Outcomes Following
Open and Endovascular Aortic Aneurysm Repairs?”
• Retrospective case-control study
• Compared ASA classification and morbidity/mortality in
233 pt who had aortic aneurysm repairs (146 endovascular
and 77 open repairs)
• In the open repair group, mortality and morbidity strongly
correlated to the ASA class with higher mortality in ASA
class 4 than class 3 patients (34% vs. 9%, p=0.006).
• In both the EVAR and the open groups, morbidity
significantly increased with higher ASA class (EVAR group:
31% for ASA 3 and 56% for ASA 4, p <0.05) and (open
group: 33% for ASA 3 and 100% for ASA 4, p <0.05).
7. Review Article: “American Society of Anesthesiologists Physical
Status Classification”
• One study showed the following relationship b/t
postoperative complication and ASA class
• ASA 1: 0.41/1000
• ASA 4/5: 9.6/1000
• ASA 1E: 1/1000
• ASA 4/5E: 26.5/1000
• Mortality rates varied significantly among different studies
• ASA 1: 0-0.3%
• ASA 2: 0.3-1.4%
• ASA 3: 1.8-4.5%
• ASA 4: 7.8-25.9%
• ASA 5: 9.4-57.8%
8. ASA Physical Status Classification
• Limited to only the pt’s medical hx and
physical/functional status
• Leaves out many other important risk factors
like…
– Type of surgery
– Necessity of surgery (Emergency vs Elective)
– Pt’s age and sex, Pt’s weight and social habits (drugs,
alcohol, tobacco)
– Pregnancy
– Airway assessment
9. ASA Physical Status Classification
• Use as a preoperative risk assessment is
controversial
• In general, studies show increased risk of
morbidity and mortality with higher ASA
scores, however…
• Ambiguous
– Provider Dependent
– ‘Systemic’ (HTN, DM) vs ‘local’ disease (Fx’s,
COPD, MI, etc)
10. Goldman Cardiac Risk Index (1977)
• In 1977, Dr. Goldman and his colleagues came up with
this system to assess risk of cardiac complications in
relatively low risk surgical candidates
• Point value assigned to each of 9 clinical risk factors
• 4 risk classes
• Not used any more due to multiple limitations,
including complexity and changes in the perioperative
care of patients
• Relative to ASA classification, it takes more time to
calculate, it takes into account labs and type of surgery,
and is usually not used in an emergency/ICU pt
12. Revised (Goldman) Cardiac Risk Index (RCRI)
• Simplified version of Goldman’s original system
• 6 independent predictors of major cardiac
complications, which similarly divides pts into 4
risk groups
• Still used today
• Recommended by the ACC/AHA for cardiac risk
assessment in surgical candidates
• Note: since only 1/3 of perioperative deaths are
due to cardiac causes, RCRI is not a good
predictor of all-cause mortality
15. “Preoperative pulmonary risk stratification for
noncardiothoracic surgery” by the ACP and ASA
• Showed that certain co-morbidities, procedures, and lab values lead
to higher odds ratio of pulmonary complications postoperatively
– ASA class> II: 2.55-4.87
– Advanced age: 2.09-3.04
– CHF: 2.93
– COPD: 1.79
– functionally dependent: 1.65-2.51
– Emergency surgery: 2.21
– AAA repair: 6.90
– Thoracic Surgery: 4.24
– Abdominal Surgery: 3.01
– Upper abdominal surgery: 2.91
– Vascular surgery: 2.10
– Albumin < 35 g/ml: 2.53
– General Anesthesia: 1.83
– (Hip surgery is not a risk factor)
16. Pathophysiological sequalae of surgical stress
response
• Cardiovascular and SNS activation
– Increased myocardial oxygen demand
– Tachycardia, Dysrhythmia, angina, myocardial infarction
• Respiratory
– Decrease TV due to pain
– Hypoxemia, hypercapnia, atelectasis, pneumonia
• Endocrine
– Hyperglycemia, Protein catabolism
– Increased cortisol, HTN, immunocompromised
• Immunologic
– Inflammation, decreased immune function, sepsis
• Gastrointestinal
– Ileus
• Renal
– Urinary retention, renal failure
• Hematologic
– Increased Platelet and fibrinogen production
– Thromboembolic events
• Central Nervous system
– Insomnia, anxiety
17. Summary
• 3 elements must be assessed to determine
risk of adverse events in a surgical pt
1. Presence of systemic diseases (HTN, DM) and
lung/heart medical conditions (COPD, hx of MI,
CVA, etc)
2. Functional status (or exercise capacity)
3. Type of surgery
18. References
• Miller, Ronald D., and Manuel C. Pardo. Basics of anesthesia. 6th ed.
Philadelphia: Elsevier/Saunders, 2011.
• Singh, K., and Danny Yakoub. “Does ASA Classifcation Correlate with
Outcomes following Open and Endovascular Aortic Aneurysm
Repairs?” Staten Island, New York. 2012.
• Daabiss, Mohamed. “American Society of Anesthesiologist Physical
Status Classification.” Indian Journal of Anesthesia. Vol 55. India.
2011.
• Shammash, J., and Stephen Kimmel. “Estimation of Cardiac risk
Prior to Noncardiac Surgery.” Evidence-Based Clinical Decision
Support at the Point of Care, UpToDate. N.p., n.d. Web 20 Sept.
2013. http://www.uptodate.com/contents/estimation-of-cardiac-
risk-prior-to-noncardiac-
surgery?detectedLanguage=en&source=search_result&search=card
iac+risk+assessment&selectedTitle=1%7E150&provider=noProvider
