Core Principles of Peri-operative Care

Question 1

What investigations should you consider in a pre-operative assessment of a patient?

Answer 1

1. CBC
2. Basic metabolic panel (electrolytes, Cr)
3. PT/PTT (mandatory if on blood thinners)
4. Pregnancy test (MANDATORY in any woman of childbearing age)
5. CXR
6. ECG (MANDATORY in patients over the age of 40 or pre-existing cardiac history)

Question 2

What are the ASA classifications?

Answer 2

I - Normal healthy patient
II - Patient with mild systemic disease
III - Patient with severe systemic disease that limits activity but is not incapacitating
IV - Patient who has incapacitating disease that is a constant threat to life
V - Moribund patient that is not expected to survive 24 hours with or without an operation
VI - Brain dead patient undergoing organ harvest
*add E for any patient undergoing emergent surgery

Question 3

What is the goal of a pre-operative cardiac evaluation?

Answer 3

Utilize history, physical and ECG to identify serious cardiac diseases such as CAD, HF, arrhythmias, presence of pacemaker, defibrillator or orthostatic hypotension.

Question 4

How long should you wait after an MI before performing an elective surgery

Answer 4

4-6 weeks

Question 5

How do you assess functional capacity and what is the goal of this?

Answer 5

Functional capacity is the ability to meet aerobic demands for an activity. and is measured in METs.
if greater than 4MET’s no further investigation. If able to climb up two flights of stairs without issues equivalent to 4 METs.

Question 6

What are specific patient risk factors for pulmonary complications following surgery?

Answer 6

1. COPD
2. Smoking
3. Pre-operative dyspnea
4. Pre-operative sputum production
5. Pneumonia
6. OSA

Question 7

What objective metric is used to assess pulmonary risk?

Answer 7

FEV1. FEV1 <0.8L/sec or <30% of predicted are at high risk for complications

Question 8

What are the two assessment tools that can be used to assess peri-operative risk in cirrhotic patients?

Answer 8

1. Childs Pugh Classification

2. MELD score

Question 9

For how long must patients quit smoking pre-operatively to significantly lower their complication risk?

Answer 9

8 weeks. If less than 8 weeks actually higher risk of complications. If 6 months or greater risk comparable to non-smokers.

Question 10

How should you manage non-insulin dependent diabetes peri-operatively?

Answer 10

Non-insulin dependent diabetics should have their medications held prior to surgery and managed with a sliding scale with regular glucose monitoring and then have them restarted in the post operative period once the patient is eating.

Question 11

How should you manage insulin dependent diabetics peri-operatively?

Answer 11

If they have insulin pumps they should continue with basal insulin and the pump will adjust as needed. Otherwise should be monitored with a sliding scale and close monitoring of blood glucose levels

Question 12

How do you manage patients with hypo or hyperthyroidism?

Answer 12

If they are not euthyroid at the time of assessment they should be assessed by an endocrinologist.

The greatest risk in the hypothyroid patient is thyroid storm (fever, tachycardia, CVS collapse etc.)

Question 13

How do you manage patients taking steroid medications and what are you concerned about?

Answer 13

Suppression of the HPA axis (adrenal crises).

In patients taking more than 20mg of prednisone each day or its equivalent for more than 3 weeks require stress dosing of steroids

need to factor in inhaled steroids and topical steroids

If patient taking 5mg of prednisone or equivalent each day - can continue with dosing and no stress dose required

Question 14

How do you stress dose steroids?

Answer 14

Give 50-100mg of IV hydrocortisone before induction of anesthesia, and 25-50mg of IV hydrocortisone q8h x 24-48h until normal steroids can be resumed.

Question 15

What is the safest time to perform surgery on a pregnant patient?

Answer 15

Second trimester. First trimester high risk of teratogenic effects from anaesthesia/radiation. Third trimester high risk of causing pre-mature labour.

Question 16

How can you assess nutritional status on history?

Answer 16

Ask about weight loss. If greater than 20lbs in 3 months prior to surgery should investigate further (albumin)

Question 17

When should you consider post-operative parenteral nutrition.

Answer 17

Patients that will be unable to meet their required caloric demand for 7-10 days after surgery (cystectomy patients)

Question 18

Who should you consider pre-operative nutritional support and what methods are available to you and preferred?

Answer 18

1. Total parenteral nutrition
   7-10 days beneficial in severely malnourished. Harmful in moderately malnourished (increased risk of sepsis)
2. Enteral feeding preferred over TPN - methods NG tubes, gastrostomy feeding or jejunostomy feeding

Question 19

What things should you consider when making patient centred decisions on antibiotic prophylaxis?

Answer 19

1. Patient susceptibility to infection.
2. Inherent infection risk of procedure
3. Potential morbidity of infection

• in older immunocompromised patients prophylaxis is reasonable for benign procedures*

Question 20

List 10 patient factors that increase the risk of infection?

Answer 20

1. Advanced age
2. Anatomic anomalies
3. Poor nutritional status
4. Smoking
5. Chronic steroid use
6. Immunodeficiency
7. Chronic indwelling hardware
8. Infected endogenous or exogenous material
9. Distant coexistent infection
10. Prolonged hospitalization

Question 21

What is the surgical classification of wounds?

Answer 21

1. Clean
   - Uninfected wound without inflammation or entry into the genital, urinary or alimentary tract. Primary wound closure, closed drainage.
2. Clean contaminated Uninfected wound with controlled entry into the genital, urinary, or alimentary tract. Primary wound closure, closed drainage.
3. Contaminated
   Uninfected wound with major break in sterile technique (gross spillage). Open fresh accidental wounds
4. Dirty Infected
   Wound with pre-existing clinical infection or perforated viscera. Old traumatic wounds with devitalized tissue.

Question 22

When should antibiotic prophylaxis be given?

Answer 22

Within 30 minutes of incision.

Question 23

List lower tract urologic procedures that warrant post-procedural antibiotic prophylaxis?

Answer 23

1. Cystoscopy with manipulation

2. TRUS Bx

Question 24

List upper tract urologic procedures that warrant post-procedural antibiotic prophylaxis?

Answer 24

1. ESWL
2. Percutaneous renal surgery
3. Ureteroscopy

Question 25

What are your choices for mechanical and pharmacologic prophylaxis against VTE?

Answer 25

1. SCD’s
2. LMWH - nephrotoxic
3. UFH - can be used in renal insufficiency

Question 26

What are patient related risk factors for VTE?

Answer 26

1. Malignancy
2. Surgery
3. Immobility
4. Smoking
5. Pregnancy
6. Trauma
7. OCP
8. Older age
9. EPO
10. Myeloproliferative disorders
11. Obesity
    12 Central venous catheterisation
12. Inherited or acquired thrombophilia
13. Nephrotic syndrome
14. Previous VTE

Question 27

How do you risk stratify urologic patients for VTE?

Answer 27

Low risk: minor surgery age < 40, no additional risk factors

Moderate risk: minor surgery in patients with additional risk factors, surgery in patients aged 40-60

High risk: surgery in patients older than 60, patients aged 40-60 with additional risk factors

Question 28

What prophylaxis measures should you take in low risk patients, moderate risk patients and high risk patients?

Answer 28

low risk - no prophylaxis (early ambulation)

moderate risk - SCD’s or heparin

high risk - SCD’s and heparin

Question 29

What is the pharmacologic half-life of warfarin and when should it be stopped prior to surgery?

Answer 29

36 hours - should stop warfarin therapy 5 days before surgery (*3 half lives) to ensure INR < 1.5

Question 30

In what patients that are anti coagulated pre-operatively should you consider bridging anticoagulation?

Answer 30

Any moderate and high risk patients

Moderate risk = A-fib (CHADs 3-4), VTE in past 3-12 months, non-severe thrombophilia, aortic valve prosthesis + 1 of (a-fib, stroke, TIA, HTN, DM, CHF)

High Risk = A-fib Chads 5+, recent stroke within 6 months, mitral valve prosthesis, severe thrombophilia, recent VTE < 3 months

Question 31

When should aspirin and clopidogrel be stopped prior to surgery

Answer 31

7-10 days

Question 32

In what setting should stopping antiplatelet therapy not be considered?

Answer 32

Cardiac stent placement. high risk of stent thrombosis if dual antiplatelets stopped within 6 weeks of a bare metal stent or within 12 months of a drug eluting stent

Should consider single anti platelet agent and communicate with cardiologist.

Question 33

What are the indications for FFP transfusion?

Answer 33

1. Immediate reversal of warfarin induced coagulopathy
2. Replacement in patients with specific clotting factor deficiencies
3. Evidence of bleeding and INR > 1.5
4. In massive transfusion

Question 34

What are the two major causes of hypothermia in the OR?

Answer 34

1. Anesthetic agents induce a peripheral vasodilation re-distributing heat
2. Conductive heat loss during the procedure

Question 35

How do you define normothermia?

Answer 35

Core temperature of 36-38 degrees

Question 36

What are some of the consequences of hypothermia?

Answer 36

1. Coagulopathy - worsening clotting cascade function, decreased platelet function
2. Increased risk of wound infection 3 fold

Question 37

What are explanatory mechanisms of patient position induced peripheral neuropathy

Answer 37

1. Excessive stretch
2. Prolonged compression
3. Ischemia

Question 38

What precautions should you take in upper extremity positioning to prevent peripheral neuropathy?

Answer 38

1. Limit arm abduction to 90 degrees or less in supine.
2. Pad ulnar groove
3. If arms are tucked at side have them in a neutral forearm position

Question 39

What precautions should you take in lower extremity positioning to prevent peripheral neuropathy?

Answer 39

1. Lithotomy positions should avoid overstitching hamstrings
2. Pad peroneal nerve (at fibular head)
3. Keep flexion of the hips to 80-100 degrees with 30-45 degrees of abduction

Question 40

List the names and locations of different kinds of incisions?

Answer 40

1. Midline abdominal incision (peritoneal and retroperitoneal access)
2. Pfannensteil (transverse lower abdominal)
3. Gibson (oblique incision in lower quadrant) - for access to distal ureters
4. Flank incision (over 11th or 12th rib for retroperitoneal access)
5. Anterior subcostal incision (for access to kidneys via peritoneum)

Question 41

What are the three phases of wound healing?

Answer 41

1. Reactive phase (24h)
2. Proliferative phase (1 week)
3. Maturational phase (1-6 weeks)

Question 42

What occurs during the reactive phase?

Answer 42

Hemostasis and inflammation.