Excellent explanation! Even though some don't like all the cancelling, I like how you explain it because it shows how you derive so the explanation works for me to see how you do it.
This formula is not even shown in the ace books at all, this way of showing the flick equation was horribly complex for no reason. These videos that pop up first makes it harder for us students to actually understand these equations to pass the fitness exam.
The bit at 3:40 that purports to be an example of "How to do it wrong" isn't wrong. Nothing cancels. That isn't wrong, it just gives you funny units at the end. People don't understand units. To convert units you just "multiply by one". But it is "one" in a special form. Note that 1 L = 1000 ml. Thus, 1000 ml/1L = 1 = ONE. For clarity I will first use the word "ONE" and multiply the 5L/minx5/100 x mlO2/ml x ONE. We're going to replace the word ONE with 1000ml/L since that quantity is equal to 1. We get 5L/min x 5/100 mlO2/ml x 1000 ml/L. Now we cancel out the L's and "ml"s. To get 5x5/100 x 1000 mlO2/min = 250 mlO2/min . The exercise physiology world is full of this kind of stuff. You need to understand unit conversion. It is actually a PROFOUND topic that sometimes goes by the name "dimensional analysis." Dimensional analysis spans all science, not just physiology. Googling "Dimensional Analysis Atom Bomb" will lead you to GI Taylor's method for determining the yield of an atomic blast from a sequence of unclassified photographs at a time when the the yield was still classified. Taylor did that with dimensional analysis. In my opinion this should have been taught by first teaching the general idea of unit conversion as multiplication by 1 and then writing down the VO2 = 5L/minx5/100 x mlO2/ml and converting the units as I did above. It was correct all along. The only difficulty is that it wasn't in its simplest form.
Just use decimal for a-vO2 difference in L per L blood and it would save all the cancelling out unnecessary maths equations that over complicate a simple process
Jontwayn didn't know that you replied to this. ive passed it, now taking another exam as an anaesthetist, and this thing somehow still haunting me 😂 wish me luck!
Why did you take the long way to solve this equation? Why didn't you just convert the ml to L first for the a-vo2 dif then multiply that by the Q?? Wasting my time and shit, making things more complicated than they have to be.
