Week 6 - Anesthesia and Obesity

Question 1

How do you calculate BMI?

Answer 1

Weight (kg) / Height (m)^2

OR

(Weight in lbs / height in inches^2) x 703

Question 2

What are the different classifications of obesity?

Answer 2

Overweight = BMI 25 or higher

• Preobese: BMI 25-29.9
• Obese Class I: 30-34.9
• Obese Class II: 35-39.9
• Obese Class III: 40 or higher

Question 3

How do you calculate IBW and LBW?

Answer 3

Men: IBW = Height (cm) - 100
Women: IBW = Height (cm) - 105

LBW = IBW x 1.3

Question 4

What are cardiovascular physiologic changes with obestiy?

Answer 4

CV disease = primary cause of morbidity and mortality associated with obesity
-Ischemic heart disease, HTN, Cardiac Failure

Increased circulatory, pulmonary, central, and peripheral blood volume

Increased demand on the myocardium –> increased L side heart pressure = LV hypertrophy

Increased CO, O2 consumption, and CO2 production (increased workload caused by elevation of basal metabolic rate)

Question 5

What are respiratory physiologic changes with obesity?

Answer 5

• Compression of fat on abdominal, diaphragmatic, and thoracic structures
• Reduced chest wall, lung, parenchyma, and pulmonary compliance
• Decreased FRC due to inhibited lung inflation
• Rapid shallow breathing
• Hypoventilation, hypercarbia, and acidosis result from depression of CNS responsiveness to chronic hypoxia