Calculations

Question 1

What does TMF mean?

Answer 1

1. Tidal volume
2. Minute volume
3. Fresh gas flow

Question 2

How do you work out
Tidal Volume?

Answer 2

BW (kg) x 10mls (if > 10kg) or 15mls (if < 10kg)

So either:
* BW (kg) x 10mls
* BW (kg) x 15mls

Answer in = mls

Question 3

How do you work out
Minute Volume?

Answer 3

MV = TV (mls) x BPM

Answer in = mls

Question 4

How do you work out
Fresh Gas Flow?

Answer 4

FGF = MV x Circuit Factor

Circuit Factors are either (Non-RB or RB):

1. 1 - 1.5 (Parrallel lack + Magill)
2. 1 = Mini Lack
   or
3. 2.5 - 3 (Ayre’s T-piece + Bains)

Answer in = Litres/min

Question 5

Calculate the FGF req for a 7kg Miniature Dachshund, on a modified Ayres T piece circuit, with a RR of 18 BPM.

Answer 5

1. TV = BW (kg) x 10 - 15 mls
   = 7kg x 15mls
   = 105mls
2. MV = TV x BPM
   = 105mls x 18 BPM
   = 1,890mls
3. FGF = MV x CF
   = Ayres T-piece = 2.5-3 Ltrs/min
   = 1890mls x 2.5-3 ltrs/min
   = 4,725 - 5670 ltrs/min
   = 4.7 - 5.6 ltrs/min

Question 6

Calculate the FGF req for a 12kg Beagle, on a modified Ayres T piece circuit, with a RR of 16 BPM.

Answer 6

1. TV = BW (kg) x 10 - 15 mls
   = 12kg x 10mls
   = 120mls
2. MV = TV x BPM
   = 120mls x 16 BPM
   = 1,920mls
3. FGF = MV x CF
   = Ayres T-piece = 2.5-3 Ltrs/min
   = 1,920mls x 2.5-3 ltrs/min
   = 4,800 - 5,760 ltrs/min
   = 4.8 - 5.7 ltrs/min