Final answer:
The calculated volume of 0.0003 mL of atropine to administer based on the provided concentration of gr 150 in mL appears to be incorrect, as this is an unmeasurable and impractical volume for clinical use.
Step-by-step explanation:
The question asks us to calculate the volume of atropine to be administered when we have a dose of 3 mg and a concentration of atropine of gr 150 in mL. The term 'gr' typically refers to a grain, an apothecaries' unit of mass that is equivalent to 64.79891 milligrams. To find out how many mL to administer, we need to convert the 3 mg ordered to grains, then use the provided concentration to find the volume.
First, we convert 3 mg to grains:
1 grain = 64.79891 mg,
3 mg × (1 grain / 64.79891 mg) = 0.0463 grains.
Since we have atropine gr 150 in mL, we next need to determine how many grains are in 1 mL:
1 mL contains 150 grains of atropine.
Finally, to calculate the volume to administer for 0.0463 grains, we use the proportion:
(150 grains / 1 mL) = (0.0463 grains / X mL),
X = 0.0463 mL / 150 grains,
X = 0.0003087 mL, which is approximately 0.0003 mL
The volume of 0.0003 mL is a practically unrealistic and unmeasurable amount for clinical purposes, indicating either a mistake in the original prescription, the concentration provided, or a misunderstanding of the dosing units.