Anaesthetic Calculations

Question 1

what are the main non-rebreathing systems?

Answer 1

bain
magill
paralell lack
t-piece

Question 2

why do we need a breathing system?

Answer 2

deliver oxygen
deliver VA
remove waste - VA and CO2

Question 3

what breathing system has it’s reservoir bag on the inspiratory limb, has a circuit factor of 1 and APL valve at the machine end?

Answer 3

lack

Question 4

what breathing system has it’s reservoir bag on the expiratory limb, has a circuit factor of 2-3, APL valve at the machine end and is coaxial?

Answer 4

bain

Question 5

what breathing system has unidirectional valves, has a soda lime canister and is very economical to run?

Answer 5

circle

Question 6

what breathing system has it’s reservoir bag on the expiratory limb, has a circuit factor of 2-3 and is not coaxial?

Answer 6

t-piece

Question 7

what breathing system has it’s reservoir bag on the inspiratory limb, has a circuit factor of 1 and APL valve at the patients mouth?

Answer 7

magill

Question 8

what non-rebreathing systems are suitable for IPPV?

Answer 8

those with the bag on the expiratory limb -
t piece and bain
circle

Question 9

what breathing systems are not suitable for IPPV?

Answer 9

those with the bag on the inspiratory limb
lack and magill
(can provide IPPV in the short term and on high flow)

Question 10

what is the circuit factor of the t-piece and bain?

Answer 10

2-3

Question 11

what patient size is a t-piece suitable for?

Answer 11

<10kg

Question 12

what patient size is a lack suitable for?

Answer 12

> 10kg to <25-30kg

Question 13

what patient size is a bain suitable for?

Answer 13

> 8 to <15-25kg

Question 14

what patient size is a magill suitable for?

Answer 14

> 5kg

Question 15

what patient size is a circle suitable for?

Answer 15

> 10kg

Question 16

what is the circle factor of a lack and magill?

Answer 16

1

Question 17

how is fresh gas flow calculated?

Answer 17

minute volume x circuit factor

Question 18

how is minute volume calculated?

Answer 18

body weight x tidal volume x resp rate

Question 19

what is the value of tidal volume?

Answer 19

10 ml/kg

Question 20

how can bag size be calculated?

Answer 20

calculate patient tidal volume (bw x 10ml/kg)

times TV by 3 and 6 to calculate a range - bag should comfortably accommodate this and not be to large

Question 21

what is the equation used to calculate drug dosages?

Answer 21

patients weight (kg) x drug dose (mg/kg)
/strength of drug mg/ml

Question 22

how do you convert micrograms to milligrams?

Answer 22

divide by 1000

Question 23

how can a % be converted to mg?

Answer 23

x10