What Is Circuit Factor

The circuit factor is a term used to describe the amount by which the calculated tidal volume of the patient is multiplied by in order to administer the correct amount of gas. Each type of circuit has its own circuit factor, apart from the closed systems (To & Fro and Circle system) – see Q21.

What is the circuit factor for a circle circuit?

NameTypeGas flowCircle systemClosed5-10mls per kg if closed (+10mls if low flow)To & fro (Waters)Closed5-10mls per kg if closed (+10mls if low flow)MagillSemi-closedCircuit factor 1-1.5LackSemi-closedCircuit factor 1-1.5

How do you calculate a gas flow vet?

1. Fresh Gas Flow Rate:
2. Tidal Volume = 10 – 15ml/kg (cats &dogs)
3. Minute Volume = Tidal Volume X Respiratory Rate.
4. Fresh gas flow rate = Minute volume X Circuit factor.