Time Constant

Question 1

3 possible causes of a patient being too deep

Answer 1

1. Vaporizer setting
2. Injectable agent dose
3. Pre existing problem increasing sensitivity

Question 2

Your patient is too deep. What do you do

Answer 2

1. Turn off vaporizer
2. Empty reservoir bag
3. Flush with O2
4. Bag if necessary
5. Watch depth change

Question 3

If unsure of depth…

Answer 3

Treat as if too deep

Question 4

Time Constance

Answer 4

How long it takes for gas in the circuit to change to the new concentration

Question 5

How long does it take to change the concentration to change to 95% of the new setting

Answer 5

5 time constants

Question 6

3 properties of time constant

Answer 6

1. Flow meter (L/ min)
2. Vaporizer (%)
3. Volume of the circuit (L)

Question 7

Two ways to increase the time constant

Answer 7

1. Increase O2
2. Empty bag

Question 8

How to calculate time constant

Answer 8

Reservoir bag x flow rate

Question 9

4 reasons MM may be pale during anesthesia

Answer 9

1. Anemia
2. Blood loss
3. Drugs
4. Vasoconstriction (hypothermic or pain)

Question 10

Tx for pale MM during anesthesia 4

Answer 10

1. Assess depth
2. Fluids
3. Blood products
4. Drugs for pain