Arch, did you mean "1 cc of the 1:10000" (i.e., 100mcg)? Cuz, 1 mg = 1 mg regardless of concentration right?
1 mg is the full code dose. This is the dose that comes in the bristojets (the tubes that you can pop the tops like Johnny and Roy used to on Emergency!) It is 1 mg in 10 cc's, or 100 mcg/ml. Higher doses hasve been studided in arrest situations but as far as I am aware they don't make much difference. If you give enough epi you can give a grapefruit a pulse.
The 1 mg in 1 cc vials (100 mcg per .1 cc) are ones that are typically used for subcutaneous administration in anaphylaxis.
The whole mcg/cc thing for epi additives to local anesthetics used to confuse me, as did the whole difference between the 1:10,000 amp and the 1:1000 amp and what those ratios actually meant.
Heres an explanation that I think makes things easier:
1 L=1 kg
This would be an equivalent mixture of each if put one kg in one liter. i.e.1:1.
Apparently the ratio always denotes the mass first
therefore, 1:200,000, if interpreted at the level of kg and liter, would be 1 kg in 200000 L
multiply each side by conversion factors to get in into workable number. Knowing that we need to get a much smaller mass, we can start with the kgs.
1kg=1000g; therefore 1:200,000=1000g in 200,000 L
divide each side by 1,000 and you get 1 gm in 200L
1gm=1000mg; therefore 1gm in 200L = 1000mg in 200L
1L=1000mL; therefore 1000mg in 200L= 1000mg in 200,000mL
divide each side by 1000 and you get 1 mg in 200 mL
Then by algebra you get 5 mcg in 1mL and hence our calculation that we need 100 mcg in 20 mL to make 5 mcg in one mL or 1:200,000 epi...
You can also use this conversion to figure out why 1:1000 epi is 1 mg per mL
OR:
The shortcut form is to look at the ratio and divide the first number (almost always 1) by the next 3 numbers (x hundred) and this will give you mg per mL
For example, 1:200,000 you would divide 1 by 200 and you get 0.005 mg per mL or 5 mcg per mL.
1:300,000 would be 1 divided by 300 or 0.0033 (3.3 mcg per mL)
This is probably more than anyone ever wanted to know about this stuff!