Obesity

Question 1

When does adipose tissue become pathologic?

Answer 1

When it starts releasing FFAs and cytokines.

Visceral fat releases the most of that, which is why android obesity carries highest health risk.

Question 2

Diagnosis of metabolic syndrome

Answer 2

Must have three of these

1) Large waist size (>40 inches for men or 35 for women)
2) TG > 150
3) HDL 130/85
5) Fasting BG > 100

Question 3

Respiratory effects of obesity

Answer 3

Restrictive lung disease pattern!

FRC reduced
VC reduced
TLC reduced
ERV reduced

CC normal

Prone to hypoxemia because of decreased FRC and increased O2 consumption

Question 4

Formula for BMI

Answer 4

(kg)/(m2)

Question 5

Appropriate TV for morbidly obese patient

Answer 5

6-8mL/kg

Larger volumes only improve oxygenation minimally and may cause sheer stress to the lungs

Question 6

Maneuver for recruiting alveoli

Answer 6

PPV to 40cmH2O and hold for 10 seconds

Question 7

How should minute ventilation be increased?

Answer 7

Using RR rather than TV

Question 8

What is the main cause of CV complications in obesity?

Answer 8

Expansion of intravascular volume and a high cardiac output state

Excess adipose tissue requires more vasculature to support their growth. More work for the heart, and the heart dilates to accommodate the extra volume.

CO increases 100mL/min for every extra kg of fat. HR is usually unchanged, so this is accomplished by increases in SV.

Question 9

Why are obese people prone to dysrhythmias?

Answer 9

Cardiac hypertrophy, CAD, and fatty infiltration o the conduction system.

Question 10

Weight based dosing for normal weight people and obese people

Answer 10

Water soluble drugs calculated on IDEAL BODY WEIGHT

Lipophilic drugs are calculated by TOTAL BODY WEIGHT

In the obese, Vd for both lipophilic and hydrophilic drugs increase, but lipophilic way more so.
Problem with this dosing is that IBW dosing may under-dose them, and TBW dosing may overdose them (fat is less vascular than other tissue)!
- Dosing based on LEAN body weight solves this issue!!!

Question 11

Pseudocholinesterase activity in the obese

Answer 11

Increased.

Sux is dosed on TBW because of increased hydrophilic Vd as well as increased activity of pseudocholinesterase!

Question 12

AHI scores and OSA

Answer 12

Mild = 5-15 episodes/hr
Moderate = 15-30 episodes/hr
Severe = >30 episodes/hr

Question 13

This is the most sensitive sign of an anastomotic leak follow gastric bypass

Answer 13

Unexplained tachycardia***

Fever and abdominal also frequently seen

Question 14

Estimated Blood Volume of obese patients

Answer 14

50mL/kg

This is because adipose tissue isn’t as vascular as lean tissue

Question 15

Fluid management in the obese population should be based on this weight

Answer 15

LBW

Question 16

FiO2 in the obese should not go over

Answer 16

80%

Going above this in the maintenance phase can cause absorption atelectasis