Chemistry word problem

Question

The typical dose of epinephrine at a particular concentration administered to a patient under cardiac arrest is 0.1 mg per kilogram of body weight. If a patient weighs 180 lb, how much epinephrine should be administered?

______mg-epi

Answer 1

Again, we will use dimensional analysis to answer this question. The conversion factors that we will need to use are:

1 kg = 2.20 lbs

Now, set up the calculation so that we convert lbs to kg and then cancel kg and end up with mg.

180 lbs x 1 kg / 2.2 lbs = 81.8 kg (this is the weight of the patient in kg)

81.8 kg x 0.1 mg / kg = 8.18 mg = 8 mg epi (rounded to 1 significant figure)

Typically these calculations are carried out in a single manipulation, as follows:

180 lbs x 1 kg / 2.2 lbs x 0.1 mg / kg = 8.18 mg = 8 mg epi

note how in the first calculation lbs cancel leaving kg, and in the 2nd calc. the kg cancel leaving mg.