Pre-op Assessment Exam 1 Flashcards
What is the (metric) formula for BMI?
BMI = kg / m²
What are the BMI parameters for underweight, normal, overweight, and obese?
- BMI < 18.5 = underweight
- BMI 18.5-24.9 = normal
- BMI 25-29.9 = overweight
- BMI > 30 = obese
What is the (imperial) formula for BMI?
(703 x lbs.) / (inches²)
What mnemonic guides an emergent physical examination?
AMPLE
- Allergies
- Medications
- Past medical history
- Last meal
- Events leading up to need for surgery
What does the airway examination include?
- Mallampati class
- inter-incisors gap
- thyromental distance
- forward movement of mandible
- Range of cervical spine motion: flexion and extension
- Document loose or chipped teeth, tracheal deviation
What is the revised cardiac risk index?
Prediction tool recommended by ACC/AHA
Estimates risk of cardiac complications after surgery
What factors are worth 1 point on the Revised Cardiac Risk Index? (6)
- High risk surgery
- Ischemic heart disease
- Hx. of CHF
- Hx. of CVA
- DM w/ insulin
- Creatinine > 2 mg/dL
What surgeries have the highest risk (>5%)?
Aortic and major vascular
peripheral vascular
What are intermediate risk surgeries? (1-5% risk)
- intrathoracic and intraabdominal
- head and neck
- carotid endarterectomy
What sort of risk would be seen on the Revised Cardiac Risk Index with a score of 0?
What about with a score of 3 or greater?
0 = 0.4% risk for major cardiac events
1= 1%
2 = 2.4%
3 = 5.4% risk for major cardiac events
*A score equal or greater than 2 is elevated risk
What are METs? What is one MET equal to?
Metabolic Equivalent of Tasks (measurement of rate of energy consumption).
Poor functional capacity = increased perioperative risk
1 MET = 3.5 mL (O2)/kg/min
How would one assess functional capacity? What is the range of this assessment?
Through METs
1 MET = eating, working at computer, etc
5 MET = climbing 1 flight of stairs, dancing, or bicycling
12 MET = running rapidly for long distances
What are the three levels of urgency of surgery? Time Frames?
Emergent - Life or limb threatened, sx needed within 6 hours, no cardiac pre-op necessary.
Urgent - Life or limb threatened, sx needed within 6-24 hours.
Time-sensitive - delays exceeding 1-6 weeks would adversely affect patient.
What ASA level would an otherwise healthy 22-year-old who got in a car wreck with massive trauma necessitating emergent surgery have?
ASA V (won’t live without sx)
AAA, MODS, ischemic bowel, CVA hemorrhage
What ASA level would a healthy non-smoking 27-year-old with well-controlled diabetes have coming in for an EGD?
ASA II (mild disease, well-controlled)
pregnancy, obesity, mild disease
What ASA level would a 56-year-old male who had an MI 2 months ago have for his follow up TEE today?
ASA IV (severe systemic disease CONSTANT threat to life)
Recent (<3 months), active cardiovascular disease, coagulopathy, renal failure, sepsis, etc.
What ASA level would a 12 year old girl with no hx have coming in for a routine tonsillectomy?
ASA I (no hx, healthy, routine sx)
What ASA level would a 42 year old male with COPD and poorly controlled DM have?
ASA III (severe systemic disease, no threat to life)
What is an ASA VI score?
Declared brain-dead patient, TOSA evaluation
What is the most common anaphylactic drug allergy? What are other common causes of anaphylaxis?
NMBs (most common)
Antibiotics (most common)
chlorhexidine (most common)
latex
opioids
what food allergies cross react with latex allergy?
- mango
- kiwi
- avocado
- passion fruit
- bananas
- chestnuts
What antibiotics are most commonly associated with allergic reactions?
PCN and cephalosporins
Vancomycin (allergy vs red man syndrome)
What conditions would prompt you to order coagulation studies?
- coagulopathy
- bleeding disorder
- hepatic disease
- anticoagulant use
- ASA 3-4; undergoing intermediate-major risk surgery
What cross-reactivity allergies are possible for someone who has a known neuromuscular blocking agent allergy?
Neostigmine & Morphine
What medications need to be discontinued for surgery?
Aspirin (10-14d) & P2Y12 Inhibitors (5-7d)
NSAIDs (48h)
Warfarin (5d)
ACEis and ARBs (24h)
Diuretics (day of)
Non-insulin DM meds (day of)
Sildenafil (unless for CHF, then continue)
Hormone Replacement Therapy (4w)
Why are ACE inhibitors and ARBs stopped 24H prior to noncardiac surgery?
Reduced rates of mortality, stroke, and MI
These drugs are associated with increased risk for hypotension during surgery due to inhibition of RAAS which normally increases BP in response to stress or anesthesia.
What herbs/supplements carry an increased risk of bleeding?
Saw Palmetto
Garlic
Ginger
Ginkgo
Ginseng
Green Tea
(essentially; saw palmetto & anything starting with a “g”)
What insulin should a type 1 diabetic take (or not take) the day of their surgery?
D/C short-acting
Continue basal rate if using a pump
Take 1/3 of normal long-acting if no pump.
What insulin should a type 2 diabetic take (or not take) the day of their surgery?
D/C short-acting
Continue basal rate if using a pump
0 - 50% of normal long-acting dose
What is the HPA Axis?
Hypothalamus, Pituitary, & Adrenal glands.
Exogenous glucocorticoids suppress cortisol production at HPA axis causing premature adrenal insufficiency and adrenal atrophy. This is why steroids must be tapered and not cut off prematurely.
When does HPA axis suppression occur?
> 20 mg prednisone/day for >3 weeks and in patients with Cushingoid appearance
How is HPA axis affected with low-dose, short acting steroids?
No HPA suppression
Which herbs/supplements carry an increased risk of excessive sedation/anxiolysis?
Kava
St. John’s Wort
Valerian
Which herbs/supplements carry an increased risk of hypoglycemia?
Ginseng
Which herbs/supplements carry a cardiovascular risk (especially intraoperatively)? Why?
Ephedra (ma huang)
Basically ephedrine = ↑ HR & BP
Which herbs/supplements boost immune system response?
Echinacea
If a patient just ate a full, fatty meal, how long until they can have surgery?
8 hours
If an infant needs an anesthetic procedure in the morning at 8AM when can their last feeding prior to this occur? (breast milk)
4AM
4 hours of NPO is required after consumption of breast milk
If a patient has toast with coffee and milk in the morning, how long will it be until they can have surgery?
6 hours
Light meals
If a patient had a gatorade at 6AM when are they clear for their anesthetic procedure?
8AM
2 hours NPO after ingestion of clear liquids
What is Mendelson syndrome? What two factors increase your risk for this?
Aspiration Pneumonitis (acute lung injury)
Increased risk of aspiration due to:
1. > 25mL of gastric contents
2. gastric pH < 2.5
What can be done to prevent aspiration pneumonitis?
↓gastric volume
↑gastric pH
What drug classes are given to help prevent aspiration pneumonitis?
Antacids (↑pH)
H2 Antagonists (ex. famotidine; ↓vol ↑pH)
PPI’s (ex. omeprazole; ↓vol ↑pH)
D2 Antagonist (ex. metoclopramide; ↓vol)
What scoring tool is used to determine PONV risk? (Post-Op Nausea and Vomiting)
Simplified Apfel Score
What are the four risk factors of a Simplified Apfel Score?
1. Female
2. Hx of PONV/motion sickness
3. Non-smoker
4. Post-op opioids
0 = no risk
4 = very high risk
What sort of risk is conferred by an Apfel score of 1-2? What would be done with this score?
Moderate-severe risk
Prevention with 2-3 antiemetics & limiting opioids.
What sort of risk is conferred by an Apfel score of 3-4? What should be done?
Severe risk
Avoid volatiles, use propofol
No opioids, if possible, use 3 antiemetics.
What other drugs are useful in prevention/treatment of PONV? (pre-medication)
Scopolamine (necessary well in advance)
GABA analogs (lower opioid usage)
Ondansetron (5HT3 antagonist)
Promethazine (H1 Antagonist)
Dexamethasone (Decadron) (may cause perineal burning)
What is the administration timing for presurgical antibiotics?
Prophylactic abx should be given within 1 hour before incision
Vancomycin & fluoroquinolone should be given within 2 hours of incision.
What chance of cross-reactivity exists with cephalosporins and penicillin?
10%
what are the 3 most common pre-operative antibiotics and their doses?
Cefazolin: 2-3g IV over 30 mins
Clindamycin: 900 mg IV over 30-60 mins
Vancomycin: 15 mg/kg IV 15 mg/min
What is the most common pre-op antibiotic?
Cefazolin (cephalosporin): broad-spectrum antibiotic
