Medical Evaluation of Surgical Risk. Johns. Katelyn Rogers. 04.13.10.
Role of Primary Care MD
Estimate surgical risk from H&P, appropriate lab and x-ray
Diagnose and manage medical problems that contribute to morbidity and mortality
Interoperate and Postoperative Death
First 48 hours – 0.3% mortality
When does the 0.3% occur:
10% - induction of anesthesia
35% - operatively
55% - postop in first 48 hours
ICSI- develop patient care guidelines for different conditions as well as preoperative care guidelines.
Interoperative and Postop Death First 48 hours
Causes – 15% each
Failure to maintain adequate ventilation
Aspiration
Arrhythmia
Drug induced myocardial depression
Hypotension from blood loss
Surgical Risk
Composed of:
Physical status of patient – as primary care MDs we have control over this one.
Surgical factors – not our role to tell them which procedure. Yet they respect what you have to say.
Anesthesia factors
Physical Status of Patient
ASA Physical Status Scale
Developed in 1940’s, modified since
Relies on accurate H & P (from primary care MDs)
Estimates surgical risk
More recent studies show good correlation with non-cardiac mortality
ASA Physical Status Scale: this is something the anesthesiologists write
Class 1: A normally healthy individual
Class 2: Patient with mild systemic disease  mild HTN for eg.
Class 3: Patient with severe systemic disease that is not incapacitating  RA, HD in past not active now.
Class 4: Patient with incapacitating systemic disease that is a constant threat to life.  CHF, angina.
Class 5: A moribund patient  near death
E: Added to any class patient with emergency surgery
Big difference is btwn Class 3 & 4. People with
systemic dxs that aren’t incapacitating do fine.
Those with incapacitating systemic dx are at a
greater risk for mortality. This is impt to evaluation
in the H & P.
Emergency surgery also tends to double the risk.
Cardiac Risk Factors in Patients Undergoing Non-cardiac Surgery
Preop is done by Cardio docs if a cardiac surgery.
Physiology of peri-operative period
Disturbance of cardiac performance
Increased cardiac 02 demand (tachycardia)
Diminished O2 supply (hypoxemia)
Anesthetic agents have two major effects: (TQ)
1) Myocardial depression (all)
2) Arrhythmogenic properties
-Pre-op arrhythmia- 0.4% risk of serious arrhythmia operatively (pretty low)
-Known pre-op heart disease- 3.9% risk of serious arrhythmia operatively
-Therefore: Serious operative arrhythmias more closely asstd w underlying heart dx than pre-op
arrhythmias alone. It is more impt the genl status of the heart! It’s okay to have some PVCs for eg.
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Goldman’s Assessment Score
Developed to assess cardiac risk of non-cardiac surgery
After analysis of various cardiac conditions, point values were assigned to
various cardiac states
Condition:
Points:
S-3 gallop or JVD
11
Myocardial infarction in past 6 months 10
PVC’s, more than 5/minute
7
Rhythm other than sinus
7
Age over 70 years
5
Emergency operation
4
Intrathoracic, abdominal or aortic surgery 3
Important aortic stenosis
3
Poor general medical condition
3
Class (Points)
I ( 0-5 )
II ( 6-12 )
III (13-25)
IV (over 26)
Morbidity
0.7%
5%
11%
56%
Mortality
0.2%
2%
2%
22%
Class III: watch post op! Class IV: Risk overall for surgery!
Look at the overall characteristics rather than the numbers. Gallop is a sign of myocardial dysfxn 
aggrevated by anesthesia  arrythmias. Also susceptible to fluid shifts.
Surgical Factors
Organ involved
Extent of disease
Skill of surgeon
Length of surgical procedures
Facilities – places that do many surgeries tend to be better at it.
Anesthesia Factors
Spinal vs. general (data indicates that they are about the same as far as safety)
Risk of intraoperative hypotension same
CHF may be worsened by general anesthesia
Gauthier (1983)- elderly patients with hip surgery showed similar mortality
Mortality Related to Anesthesia (no statistical difference, both are very safe)
ASA
Spinal
General
1
1: 100,000
1: 25,000
2
1: 3,500
1: 1.000
3
1: 400
1: 350
4
1: 35
1: 46
5
1: 16
1: 24
None of above are statistically significant
Summary of Surgical and Anesthesia Factors (Goldstein)
Poor physical status
Race (non-whites)
Poor physical fitness
Long duration of anesthesia and surgery
Cardiac disease (angina, CHF)
Surgery of vital organs
Extremes of age
Complex surgery
The adult male
Emergency surgery
Depression or anxiety – You can help with this. Help feel
Lack of skill, infrequent performance and excessive
confident.
aggressiveness of surgeon
What Isn’t on Goldman’s Scale?
Hypertension: several studies show no increased risk if diastolic is less than 110
Stable angina: threefold increase in cardiac complicationsbut no overall increase in death
Notes
Murmurs- risk highest for symptomatic aortic stenosis (8X). Mitral regurgitation risk (3X). If not symptomatic than not sig.
Post-op MI’s (what people worry about!)
60% occur in first 3 days
70% occur by days 4-6
50% are silent
The mortality overall is 50-70%
Hypokalemia
Serum K should be over 3.0 (normal is over 3.5)
If on digitalis should be over 3.5
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Anemia
Tissue oxygen supply variables:
1) cardiac output
2) hemoglobin
3) A-V oxygen saturation % difference
Remember!
Normal blood volume is more important than the actual hemoglobin value.
The hemoglobin should be over 10 if significant blood loss is expected during surgery.
BV is impt bc upon administration of anesthetic they can become severely hypotensive. How do you know if they have low
blood volume? You have to lose ½ your blood vol to become hypotensive, so how would you test it? Capillary refill will help
you see how well they are perfusing. Another is postural BP checks. Lying down may have normal pressure, stand them up
may severely decrease their BP. If this happens then the BV is low!
Basic Rules for Elective Surgery (Good Summary!)
1) No surgery within 6 months of a M.I.
2) No surgery in the patient has active CHF or its’ signs (crackles, S3).
3) Stable angina does not carry an increased risk, unstable angina does.
4) Hypertension with a diastolic under 110 does not carry an increased risk.
5) Pre-op arrhythmias are more significant if associated with underlying heart disease.
6) Potassium over 3.5 if on digitalis, 3.0 if not.
7) The hemoglobin should be over 10.0 in a patient with coronary artery disease,over 8.5 in other patients.
8) From a medical standpoint, spinal anesthesia is not significantly safer than general anesthesia. They are both safe.
9) In emergency surgery you have to weigh the benefits and the risks, there are no firm rules!
Should We Clear This Patient For Surgery? (KNOW THESE!)
1) 45 year old male scheduled for an elective hernia repair. He had a myocardial
infarction 5 months ago and has been free of cardiac problems since. Yes or No
2) 54 year old female with a blood pressure of 166/98 is scheduled for an
elective hysterectomy. Yes or No
3) 65 year old female scheduled for a mastectomy for cancer. She denies
shortness of breath but has a S3 gallop and bilateral lung crackles. Yes or No
4) 78 year old male is scheduled for a lumbar laminectomy and has a
hemoglobin of 9.8. He has a known chronic anemia and does not have heart
disease. Yes or No
5) A 66 year old male on Lasix (furosamide) has a potassium of 3.4 (normal 3.5-5.
He is scheduled for knee surgery and is not on digitalis. Yes or No
6) 89 year old female with mild CHF, stable angina, hemoglobin of 8.2, chronic
renal failure with a creatinine of 2.8, and a mild myocardial infarction about 5
months ago, is scheduled for a cataract extraction. Yes or No
Order UA, electrolytes if on dialysis, EKG over age of 50, and hemoglobin are all
impt tests to do before a surgery.
Questions:
1. What is the most important factor for evaluating the physical status of a patient for
surgery?
2. When does surgical mortality increase, in which classes of the ASA physical status scale
and what characteristics would be seen?
3. What are the two major risk effects of anesthesia?
4. T/F. Serious preoperative arrhythmias are more closely associated with underlying heart
disease than pre-op arrhythmias alone.
5. T/F. Hemoglobin value is more important than a normal blood volume.
Answers:
1.
2.
3.
4.
5.
An accurate H & P by the primary care MD.
Between class III & IV. Once the patient has an incapacitating systemic disease.
Myocardial depression and arrythmogenic properties.
T
F
Case Answers:
Answer to #1
No- remember the 6 month rule. The risk of
cardiac complications is highest in the
first 6 months after an MI. If incarcerated
hernia then maybe have to do it.
Answer to #2
Yes- the diastolic should be under 110 for
surgery.
Answer to #3
No- the presence of congestive heart failure
or its’ physical signs carries a high risk
of postop CHF and pulmonary edema.
Answer to #4
Yes- since his anemia is chronic, we can
assume his blood volume is normal.
Blood volume is more important than
the absolute hemoglobin. The blood
loss from a laminectomy should be
minimal.
Answer to #5
Yes- his potassium is over 3.0 and he is not on
digitalis.
Answer to #6
Yes- when it comes to cataract surgery done
under local anesthesia, almost every
patient is a candidate. The only real
contraindication is a bad cough which
can elevate intra-ocular pressure.
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