6/5/23 Notes Flashcards
What is anatomic dead space?
1mL/lb
What are some areas where volume is lost in the patient conducting airway and where no gas exchange occurs?
Trachea & bronchi
What are some devices that can increase or decrease the amount of Vdmech added to the breathing circuit.
• ETT
• closed suction system
• HMEs
What is the formula for Ve?
Vt x RR
What is the formula for VA?
(Vt-Vd) x F
What are the 2 factors that must be considered in determining VA?
• Anatomical dead space
• Mechanical dead space
What are some things that can add mechanical dead space to to the vent circuit and affect the the Vd/Vt.
• HMEs
• Closed suction system
• Other circuit adapters
Adjustment in flow rate alters _____?
Ti
I:E ratio is adjusted by what 3 vent controls?
• Vt control
• Flow rate
• RR
Increased Flow =
Decreased Ti
Decreased flow =
increased Ti
Higher Vt =
Higher Ti
Lower Vt =
Lower Ti
Increased RR =
Decreased Te
Decreased RR =
Increased Te
What is TCT?
Ti + Te
After you get your answer for TCT what do you divide by to get the RR?
60
Ex. TCT=Ti+Te
60 s/TCT = F
How do you improve O2?
- Increased FiO2
- PEEP (refractory hypoxemia)
- Improve ventilation
- APRV or Bilevel ventilation (focuses on MAP)
- Pressure control with inverse ratio ventilation
- Proning
What is inverse ratio?
Ti is longer than Te
Ex. 1:2 ➡️ 2:1
What does inverse ratio help with?
More time for inspiration and gas exchange
What is the normal TCT?
3-5 secs; RR 12-20 bpm
What is the Vt & rate for COPD pts?
6-8mL/kg ; 8-12 bpm
What are the formula for Vt?
Vt = Ve/RR
What is the formula for Raw?
PIP-Pplat/Flow
What is the formula for the A-a gradient?
PAO2-PaO2
What is the formula for dynamic compliance?
VT/PIP-PEEP
What is the formula for dead space?
PaCO2-PeCO2/PaCO2
What is the formula for static compliance?
CS = VT/(Pplat − PEEP)
T or F Dividing by different RR gives different times?
True
Ex. 7-6 sec
What is the formula for flow?
VT/Ti
What is the formula for RR?
RR= Ve/Vt
What it’s the equation for I:E ratio?
I:E = Ti/Te
