Preoperative Evaluation and Management

What does the Joint Commission on Accreditation of Healthcare Organizations (JCAHO) require for all patients before surgery?

Preoperative anesthetic evaluation

What are the primary and secondary goals of the preoperative evaluation?

Primary Goals

→ Reduce patient risk

→ Reduction of perioperative morbidity and mortality

Secondary Goals

→ Promote efficiency

→ Reduce costs

What are the most common conditions that lead to modification of the anesthetic plan? What part of the anesthetic is usually modified?

1. Gastric reflux

2. Insulin-dependent diabetes mellitus (IDDM)

3. Asthma

4. Suspected difficult airway

→ The induction technique is usually modified

When can a preoperative anesthetic assessment be performed?

1. Prior to the patient coming to the OR

2. Outpatient visit

3. Inpatient

4. Pre-operative (same day)

5. Emergency Room (ER)

6. Intensive Care Unit (ICU)

In the Emergency Room, what are the most important preoperative assessment questions?

1. Allergy history

2. Current medications

3. Time of last oral intake

What are the main components of the preoperative evaluation?

1. Review of medical records

2. Personal interview

3. Physical examination

What should be reviewed in the medical records during a preoperative evaluation?

1. Medications

2. Substance use

→ Alcohol

→ Tobacco

→ Recreational/illicit drugs

3. Surgical history

4. Surgical diagnosis

→ Organ systems involved

→ Planned procedure

5. Preoperative labs

→ Hgb, Hct, PT, PTT, INR, BMP

→ Type & screen/cross

→ Pregnancy test

→ ECG

→ Chest X-ray

What should be covered in the personal interview during a preoperative evaluation?

1. Review of systems

2. Prior anesthetic experiences

→ Difficult intubation

→ Delayed emergence

→ Malignant hyperthermia

→ Prolonged neuromuscular block

→ PONV

3. Drug allergies

What should be included in the physical examination during a preoperative evaluation?

1. Airway exam

2. Body habitus

What are the common uses of garlic as a supplement? What are the pharmacologic effects of garlic?

Common uses:

→ Lower cholesterol, BP

→ Antioxidant

Pharmacologic effects & Drug interactions:

→ Inhibition of platelet aggregation = Potential for increased bleeding

What are the common uses of St. John's wort as a supplement? What are the pharmacologic effects of St. John's wort?

Common uses:

→ Treats depression and anxiety

Pharmacologic effects & Drug interactions:

→ May prolong the effects of anesthesia

Patients taking GLP-1 agonists are at increased risk for what perioperative complication?

Gastroparesis

→ Higher aspiration risk during induction and extubation

What are the ASA Physical Status Classifications?

ASA 1: Normal healthy patient

ASA 2: Mild systemic disease, no functional limitation

ASA 3: Severe systemic disease, some limitation

ASA 4: Severe systemic disease, constant threat to life (incapacitated)

ASA 5: Moribund patient, not expected to survive without an operation

ASA 6: Brain-dead patient, organ donor

E: Emergency procedure modifier (Ex: ASA 2E)

True or false: Mallampati classification is a strong predictor of a difficult airway

False

→ MP class has a low predictive value of difficult airways

Which two specific airway assessments, when combined, better predict difficult intubation?

High Mallampati class + Thyromental distance <6 cm

What is the thyromental distance? In what position is it measured?

1. Distance from the thyroid notch to the inside of the mentum

2. Measured with the neck in the sniffing position

What features of the following can lead to difficult intubation:

1. Neck

2. Soft tissue

3. Teeth

4. Jaw

1. Neck:

→ Short, thick neck (circumference >40 cm)

→ Limited extension

2. Soft tissue:

→ Decreased tissue compliance (Ex: Neck radiation)

→ Large tongue

3. Teeth

→ Large teeth

→ Overbite

4. Jaw

→ Decreased TMJ mobility

Predictors of difficult ventilation

1. Edentulous

2. Hx of snoring

3. Macroglossia

4. Micrognathia

5. Obesity

6. OSA

7. Beard

Predictors of difficult intubation

1. Hx of difficult intubation

2. Inability to prognath (protrude lower jaw)

3. Limited neck ROM

4. MP class III or IV

5. Mouth opening <4cm

6. Obesity

7. Thyromental distance <6cm

What is both a predictor of difficult ventilation and difficult intubation?

Obesity

NPO Guidelines for

1. Clear liquids

2. Breast milk

3. Infant formula and Non-human milk

4. Light meals (low fat & protein content)

5. Heavy meals

Clear liquids → 2hrs

Breast milk → 4hrs

Infant formula and Non-human milk → 6hrs

Light meals → 6hrs

Heavy meals → 8hrs

What factors increase aspiration risk during anesthesia in the following situations:

1. GI pathology/conditions

2. Bleeding

3. Delayed gastric emptying

4. Altered consciousness

5. Surgical context

1. GI pathology/conditions

→ Obstruction

→ GERD

→ Abdominal distention

→ Pregnancy

2. Bleeding

→ Upper GI or naso/oropharyngeal bleeding ± trauma

3. Delayed gastric emptying →

→ Uncontrolled diabetes mellitus

→ Recent opioid use

4. Altered consciousness

→ Depressed LOC

5. Surgical context

→ Recent solid food intake

→ Emergency surgery

A patient with tobacco use, asthma, SOB/DOE, sleep apnea, wheezing, or cough has issues pertaining to which system?

Pulmonary

What should you assess on physical exam of the pulmonary system?

1. Lung sounds

2. Chest excursion

3. Use of accessory muscles

4. Cyanosis

5. Clubbing

A patient with a history of HTN, CAD, MI, angina, CHF, dysrhythmias, or valvular disease has issues pertaining to which system?

Cardiovascular

What should you assess on physical exam of the cardiovascular system?

1. Heart sounds

2. Carotid bruits

3. Peripheral pulses

4. Blood pressure

A patient with a history of insufficiency, ESRD, dialysis, liver disease, hepatitis, bowel obstruction, reflux, or alcohol use has issues pertaining to which system?

Renal/GI/Hepatic

A patient with a history of seizures, mental status changes, neuromuscular disease, or nerve injury has issues pertaining to which system?

Neurologic

What should you assess on physical exam of the neurologic system?

1. Strength

2. Reflexes

3. Sensation

A patient with a history of diabetes mellitus, thyroid disease, or adrenal cortical suppression has issues pertaining to which system?

Endocrine/Metabolic/Infectious/Other

What type of complications occur in 5-10% of non-cardiac surgeries?

Pulmonary complication

Which procedures are associated with increased pulmonary complications?

Thoracic and upper abdominal procedures

What should you assess during the interview of a patient with pulmonary disease?

1. Exercise tolerance

2. Chronic cough

3. Smoking history

Wheezing:

1. Type of sound

2. Why does it occur?

3. When is it heard?

1. Sound type → High-pitched, continuous, musical

2. Cause → Airflow through a narrowed airway

3. Timing → Heard on inspiration and expiration

Crackles:

1. Type of sound?

2. Why does it occur?

3. When is it heard?

1. Sound type → High-pitched popping sound

2. Cause → Air being forced through narrowed or collapsed small airways/alveoli

3. Timing → Heard mostly on inspiration

Which type of crackle:

1. Sound like hair rubbed between fingers

2. Has low bubbling sound that often clears with coughing

Fine crackles → Sound like hair rubbed between fingers

Coarse crackles → Low bubbling sound that often clears with coughing

Rhonchi:

1. Type of sound?

2. Why does it occur?

3. When is it heard?

1. Sound type → Low-pitched rumble (like a snore)

2. Cause → Narrowed airway in trachea or bronchi

3. Timing → Heard on inspiration and expiration

→ Clears w/ cough

Stridor:

1. Type of sound?

2. Why does it occur?

3. When is it heard?

1. Sound type → High-pitched wheezing sound

2. Cause → Obstruction of the upper airway (disrupted airflow in the larynx or trachea)

3. Timing → Heard on inspiration mostly

Pleural friction rub:

1. Type of sound?

2. Why does it occur?

3. When is it heard?

1. Sound type → Harsh grating, leathery sound

2. Cause →Friction of inflamed and roughened pleura

3. Timing → Heard on inspiration and expiration

Pleural friction rub is often mistaken for

Coarse crackles

Increased distance between the lung and the chest wall can cause __________ lung sounds

Absent or diminished

What sound can the following conditions cause:

1. ARDS

2. Epiglottitis

3. Emphysema

4. Airway inflammation

5. CF

6. Tumor

7. Foreign body in airway

8. Infections of bronchi/bronchioles/alveoli

9. Lung collapse

10. Effusion

11. Asthma

12. Bronchitis

13. Croup

14. Rheumatic fever

15. Pulmonary edema

16. Complete obstruction

17. Autoimmune disorder

18. COPD

19. Chest trauma

20. Fibrosis

21. TB

1. ARDS → Crackles

2. Epiglottitis → Stridor

3. Emphysema → Absent or diminished sound

4. Airway inflammation → Wheezing

5. CF → Rhonchi

6. Tumor → Absent or diminished sound

7. Foreign body in airway → Stridor

8. Infections of bronchi/bronchioles/alveoli → Crackles

9. Lung collapse → Absent or diminished sound

10. Effusion → Absent or diminished sound

11. Asthma → Wheezing or absent or diminished sound

12. Bronchitis → Rhonchi

13. Croup → Stridor

14. Rheumatic fever → Pleural friction rub

15. Pulmonary edema → Crackles

16. Complete obstruction → Absent or diminished sound

17. Autoimmune disorder → Pleural friction rub

18. COPD → Rhonchi

19. Chest trauma → Pleural friction rub

20. Fibrosis → Absent or diminished sound

21. TB → Pleural friction rub

Adverse effects of smoking

1. Decreased mucociliary clearance

2. Increased sputum production

3. Stimulation of the CV system

4. Increased carboxyhemoglobin levels

What is the effect of smoking cessation for 2 days before surgery?

Decreases carboxyhemoglobin (COHb) levels

What is the effect of smoking cessation for 4–8 weeks before surgery?

Decreases the rate of postoperative pulmonary complications

Normal COHb levels

0-3%

Smoker COHb levels

3-8%

How to calculate number of pack years

[# of packs/day smoked] x [# of years smoked]

Major CV disease categories

1. Coronary heart disease (CHD/CAD)

2. Hypertension (HTN)

3. Rheumatic heart disease (RHD)

4. Bacterial endocarditis

5. Congenital heart disease

In the Goldman risk index, what are the independent predictors of perioperative cardiac complications related to:

1. Heart history

2. Type of surgery

3. Therapy

4. Serum creatinine

1. Heart history:

→ History of ischemic heart disease

→ History of CHF

→ History of cerebrovascular disease

2. Type of surgery:

→ High-risk surgery

3. Therapy:

→ Preoperative insulin therapy

4. Serum creatinine:

→ >2 mg/dL

According to the Goldman risk index, what are the rates of major cardiac complications based on the number of predictors?

0 predictors → 0.5%

1 predictor → 1.3%

2 predictors → 4%

3 predictors → 9%

True or false: Recent MI or ECG changes (<30 days) before the procedure increase risk of MI during anesthesia

True

What tests may be ordered for a patient with known cardiac disease during preoperative evaluation?

1. ECG or Holter monitoring

2. Stress test (exercise or pharmacologic)

3. Echocardiography or angiography

What cardiac interventions may indicate the need for evaluation before current elective surgery?

1. Cardiac stents

2. Balloon angioplasty

3. CABG

1 MET is equal to what?

3.5 mLO₂/kg/min

What questions can you ask a patient to gauge 1 MET?

1. Can you take care of yourself?

2. Light housework?

What questions can you ask a patient to gauge 4 METs?

1. Climb a flight of stairs?

2. Heavy work around the house?

3. Golf, bowling, doubles tennis (light sports/exercise)?

What questions can you ask a patient to gauge >10 METs?

Strenuous sports like swimming, singles tennis, or skiing?

What do you check the day of surgery for a patient with DM?

Blood sugar

DM is associated with what CV complications?

1. Increased risk of CAD

2. Perioperative MI

3. HTN

4. CHF

To help limit myocardial ischemia in diabetics w/ CAD, what might you consider?

Beta-blockers

True or false: Surgical stress will not raise glucose levels

False

→ Surgical stress will raise glucose levels; consider possible treatment

What systemic disease will lead to altered drug metabolism and fluid management?

Renal disease

What systemic disease will lead to coagulation abnormalities and altered protein binding and volume of distribution?

Liver disease

Chronic OSA can lead to what complications?

1. Pulmonary HTN

2. Right heart failure

True or false: Patients with OSA are usually not susceptible to respiratory depressants both intraoperatively and postoperatively

False

→ They are usually susceptible to respiratory depressants both intraoperatively and postoperatively

Positioning difficulty, difficult intubation, and atlanto-occipital (AO) joint instability may be caused by what condition?

Arthritis

True or false: A positive result on preoperative screening tests is frequently a false negative

False

→ A positive result on preoperative screening tests is frequently a false positive

What hemoglobin levels are generally acceptable before surgery (depending upon the proposed surgical procedure) in:

1. Patients without systemic disease

2. Patients with coronary artery disease

1. Patients without systemic disease → 7g/dL

2. Patients with coronary artery disease → 9-10 g/dL

What is an indication for transfusion in patients with systemic disease?

Signs of inadequate oxygen delivery

True or false: Creatinine and glucose should be tested in all older asymptomatic patients

True

What preoperative tests are indicated for patients with renal disease or on medications that affect the kidneys?

1. BUN

2. Creatinine

When are coagulation studies recommended preoperatively?

1. Patients with bleeding disorders

2. Patients with liver dysfunction

3. Patients on anticoagulant therapy

When to do an EKG?

1. Age >50

2. Hx of HTN or cardiac disease

When are chest x-rays indicated?

1. Pts with history or clinical evidence of active pulmonary disease

2. Patients of advanced age

True or false: Routine chest X-rays are always beneficial in patients without risk factors

False

→ Can lead to more harm than good

When should type & screen or type & cross be done preoperatively?

1. Potential for high blood loss in surgery

2. Increased risk of transfusion

3. Anemia

Goal of premedication

1. Anxiolysis

2. Sedation

3. Amnesia

4. Analgesia

Act on GABA receptors to produce selective anxiolysis at doses that don't produce excessive sedation, depression of ventilation, or adverse cardiac effects

Benzodiazepines

Used when there is a need to provide analgesia

Opioids

Administered in the preop or intraop period as prophylaxis against PONV

Antiemetics

What antiemetic is black-boxed?

Droperidol (inapsine)

Adult PONV risk factors

1. Female

2. Non-smoker

3. Hx of motion sickness or PONV

4. Pain

5. High levels of anxiety

6. Long surgical procedure

7. Type of surgery

→ Intra-abdominal

→ Gynecologic

→ Laparoscopic

→ Breast

→ ENT

→ Strabismus

Child PONV risk factors

1. Surgery >30min

2. >3yo

3. Strabismus surgery

4. Hx of POV; relative w/ PONV

What is the incidence of PONV based on:

→ 0 risk factor

→ 1 risk factor

→ 2 risk factors

→ 3 risk factors

→ 4 risk factors

0 = 10%

1 = 20%

2 = 40%

3 = 60%

4 = 80%

True or false: Postoperative opioid use reduces the risk of PONV

False

→ Postoperative opioid use increases the risk of PONV

When should dialysis be performed preoperatively?

Within 24 hours before surgery