"The breath analysis and the number that you get works on three major variables and they are, one the volume of the sample, that is the breath that's delivered?---Yeah, that's 1.2 litres.
Yep. The other one is the temperature at which the breath is delivered and exhaled into the mouth piece?---It's 34 degrees Celsius.
It's supposed to be 34 degrees?---Well, that's - - that's what's written in a lot of - -
But that's not because - -?--- ...(indistinct)...
That's not because is it. Because the machine itself somehow takes the breath and heats it to 34 degrees?---No, it doesn't do that at all.
It depends on the actual temperature that it's exhaled at - that is, that the person delivers it at?---No, the instrument is set at a certain temperature and the cuvette is set at 40 - -
So - - ?--- - - 44 degrees and the hose is set at 42 degrees - -
That's right?--- - - to compensate.
And it then works out on the basis that the temperature that it's delivered at is 34 degrees?---That's what we've been led to believe, yes.
MR PAPAMIHAIL: That's what you're led to believe. But no one's certain, are they, from case to case, at what temperature it is actual delivered?---Well, I think it's a - - a known fact that it's - -
No, no, I didn't ask about a known fact?--- - - 30 - - 34 degrees.
I said from breath to breath there's no certainty as to what temperature the breath temperature is delivered at, is there?---I'm not too sure.
All right, and the other factor that's also different as well is the breathing style. Do you understand what I mean by breathing style?---Well, I presume you're saying when it's exhaled from the mouth.
Yep?---How do you - - how do you breathe out.
Do you know the difference between what is called hyperventilation and hypoventilation?---I know what hyperventilation is.
Hyperventilation is when you breathe very, very quickly. You change the volume of oxygen in your lungs?---That's right.
And then you exhale?---Yes.
So the composition of what you're breathing out is different because you can actually cause yourself to become light headed?---Certainly.
Yeah?---We've tried that.
So what I'm saying to you is there is a presumption when the machine makes it measurement and the - - the machine makes it's measurement on this basis. It's based on the volume of the sample that's delivered into it, agreed?---There is 1.2 litres required, yes.
Yep. That the temperature is a certain temperature?---That's based on 34 degrees.
Yes?---What the calibrators are set out when we calibrate.
And the style that the breath is delivered, the pressure?---No, pressure is really irrelevant.
This - - the way that the breath is delivered?---As long as there is 1.2 litres of air or a litre of air supplied to the instrument it will give a result. If there's any less than that it will not give a result. It must have at least 1 litre of air."