Wk 1: Obesity 1-9

Question 1

What is obesity? (definition)

Answer 1

BMI > 30kg/m2

A disorder of energy balance, associated c incr. morbidity & mortality and a variety of med/surg problems.

Question 2

How is BMI calculated?

Answer 2

BMI = weight (kg)/height2 (m2)

Question 3

Incidence of obesity in US?

Answer 3

65% overweight (adults)

30% obese (adults)

Question 4

Preoperative concerns for obese patient?

Answer 4

• Assess: prior MI, HTN, Angina, PVD, exercise tolerance
• Consider: CXR, ECG, PFTs, ABGs, Vascular Access
• Meds: home medications, Aspiration Prophylaxis
• Airway Exam: TM and atlanto-occipital joints lim. ROM, narrow airway, redundant tissue
• Preparation: airway equipment, monitors, positioning, OR bed

Question 5

Intraop concerns for obese patients?

Answer 5

• Rapid ↓ PaO2 (preoxygenate)
• Consider: RSI, awake FOI; Initial drug doses based upon IBW
• Anesthetic technique: GA, Regional (technically difficult), MAC, Local
• Fully awake extubation in sitting position
• Volume Replacement: TBW 40% in severely obese, (60-65% in nonobese)
• EBV calculated using 45-55 mL/kg rather than 70 mL/kg as with nonobese
• Avoid rapid rehydration
• Positioning & Integumentary Issues: extra padding & skin protection, panniculus management

Question 6

Post-op concerns for obese patients?

Answer 6

• Semisitting position (45 ˚ head up), Nasal Airway, Pulse Oximetry
• Supplemental Oxygen, CPAP if OSA
• Pain Management: Narcotics, NSAIDS, PCA (IBW dosing); greater sensitivity to respiratory depression
• Problems: Respiratory failure, DVT, PE, wound infections

Question 7

Induction factors to consider c obese pts?

Answer 7

Prepare for difficult mask ventilation & intubation
Rapid desaturation, airway collapse
Consider awake FOI, surgical airway intervention (trach)

Question 8

Maintenance factors to consider c obese pts?

Answer 8

High FiO2- prone, Lithotomy, trendelenberg positions
Watch ETCO2
Careful positioning is necessary

Question 9

Emergence factors to consider c obese pts?

Answer 9

Complete MR reversal

Fully awake extubation

Question 10

How should an obese airway be examined?

Answer 10

Detailed assessment necessary:
Consider mask difficulty (fat faces, short neck, big ol’ tongue, redundant tissue, restricted mouth opening, large breasts…)

Question 11

Safest way to induce and maintain obese pt?

Answer 11

Aspiration risk: H2 blocker, PPI, nonparticulate antacids
Consider awake fiberoptic intubation.
PROPER POSITIONING

Question 12

Respiratory changes in morbidly obese pts?

Answer 12

Increased incidence of baseline lung disease – asthma, OSA, restrictive lung disease, pulmonary HTN, chronic hypoxia
↑ Work of breathing	
↓ Respiratory compliance
↓ Diaphragmatic excursion
↓ Functional Residual Capacity
↓ Expiratory Reserve Volume
↓ Total Lung Capacity
↑ Hypoventilation & atelectasis

Question 13

LMAs safe in obese pts?

Answer 13

Obese considered “full stomach”
Higher peak pressure needed to ventilate less compliant lung tissue

BUT LMAs are still an emergent Plan B!!!