A recently introduced local anesthetic agent is claimed by the manufacturer to be several times as potent as procaine. The product is available in 0.05% buffered aqueous solution in 1.8 ml. cartridge. The maximum amount recommended for dental anesthesia over a 4- hour period is 30 mg. The amount is contained in approximately how many cartridges?

1 explanations

1. 

   Angelok890

   0.05% = 0.5 mg/ml . To give 30 mg, you have to give 30mg/0.5 mg/ml or 60 ml. 1 cartridge = 1.8 ml, thus 60ml /1.8ml = 33.3 cartridges. - first express the percentage of solution as a fraction of 100, then add the units gm/ml. 0.05% equals 0.5 or 1/2 gms per 100 ml. The cartridge is 1.8 ml which you can round off to almost 2 mls total. In this 2 ml you would have 1 gm of the local anesthetic. You need to give 30 gms, which would require 30 cartridges. The alternative that meets this answer is (d). Don't get tricked by the placement of the decimal pointmany people read the 0.05% as being the same as 5 gms rather than 0.5 gms.

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