Complex Math

In my last EMT class we were given a simple linear equation to guesstimate the normal systolic blood pressure of a child (i.e., age x 2 + 80). Combine this with the knowledge that not everyone in the class is playing with the same intellectual cards and we come to today’s example:

Instructor: So with this formula you can estimate the normal blood pressure of children of various ages.

Student X with quizzical look on face: Um, I think there is a problem with your formula.

Instructor: How is that?

Student X: Well, an 8 month old would have the same predicated BP as an 8 year old.

It is at this point I begin to feel sorry for the guy, but to my surprise nobody laughs. Even more surprising are the couple of heads nodding in agreement and/or pleasure that X has found a flaw in the instructor.

It gets better…

Instructor: No, No, I see your problem. No, see in the case of an 8 month old you’d multiple by 0.8 (no, this isn’t a typo and it isn’t rounded – you had to be there for the tone).

I’m waiting for someone to catch the instructor’s mistake. And waiting. Given the defensiveness and ego of the instructor I’m not about to challenge him on something that makes no realistic difference (we are talking about differences in numbers that are not meaningful in any kind of EMS setting). However, I did have a powerful urge to ask him how we would handle the math for an 11 month old.