Ventilator Stuff

Question 1

What is normal minute ventilation?

Answer 1

4-5 L/min

Question 2

What are the initial settings for severe bronchospasm?

Answer 2

Assist-control ventilation
10-14 breaths/minute
I:E ratios of 1:3-1:5
constant inspiratory flow
TV 8 mL/kg PBW
PEEP zero
FiO2: start at 100%, adjust down to keep O2 >88%-95%

Question 3

You have a patient with status asthmaticus who is still decompensating on best vent settings, what can you consider next?

Answer 3

• have reduced RR already
• have a slightly higher Tv already
• now consider heliox, ketamine infusion, or therapeutic bronchoscopy

Question 4

What are the 7 types of physiologic mechanisms of hypoxia?

Answer 4

1. Shunt
2. V/Q mismatch
3. Diffusion limitation
4. Dead Space
5. Low FiO2
6. Low barometric pressure
7. alveolar hypoventilation

Question 5

What is the alveolar gas equation? what is it’s purpose?
What is the simplified version of the equation for a person breathing room air?

Answer 5

Tells us what partial pressure of oxygen should be
PAO2 = (Pb - Ph20) x FiO2] - PaCO2/RQ
RQ is the ratio of CO2 production to oxygen consumption (usually .8)
PAO2 = 150 - 1.2(PaCO2)