calculations

Question 0

PROPORTIONS:

how many ml of 0.75% bupivicaine do you need to give 12 mg?

Answer 0

1%= 1000 mg in 100 mL (percent means per 100), so…
.75% bupivicaine=.75 grams (or 750 mg) in 100 ml or 7.5 mg/ml
(which is 750 mg/100)
1ml/7.5 mg=xmL/12 mg»
(12 mg)1ml/7.5 mg=xmL/12(12 mg)»
12 mg/7.5 mg=x mL
x=1.6 ml

Question 1

DIMENSIONAL ANALYSIS:
how would you convert atmospheres into psi?
ex: 700 mmhg=? Psi

Answer 1

700 mmHg=? psi
760 mmhg=14.7 psi
700 (14.7/760)=
       (14.7/760)= 0.01934
700 x 0.01934=13.54 psi

Question 2

DESIRED AND AVAILABLE:

If you have 1 gram of remifentanil and you need 50 mg/ml, how much diluent do you use?

Answer 2

1 gram=1000 mg
x ml/1 gram= 1 ml/50 mg
1000 mg/50 mg x ?mL=
20 mL of diluent

Question 3

LESTERS NO MATH RULE:

if you have 400 mg in 250, how many mcg/min will you deliver at 15 cc?

Answer 3

because 250mL is 1/4 of 1000 mL, you can divide the amount of 250 ml by 1000 and divide the amount of mg by 1000. therefore there are 400 mcg in .25 ml

Question 4

FRACTION TO RATIO:
what does 1/3 mean?
what does 1:3 mean?

Answer 4

1/3 means 1 of 3

1:3 means 1 of 4 (1+3=4)

Question 5

RATIOS IN ANESTHESIA:

1. epinephrine-1:100,000= what is the breakdown?
2. what about epi 1:1,000?
3. epi 1: 10,000?

Answer 5

1. -1 gram in 100,000 ml which = 1,000/100,000 or
   1mg/100 ml which is»>
   1000 mcg in 100 ml»>
   10 mcg/ ml
2. -for 1;1,000= 1 gram (1000 mg ) in 1000 ml or 1 mg/ml
   usual dose=0.1-0.5 mg which is 1/10th to 1/2 of a cc (in a TB syringe) max 1 cc IM or SQ as a bronchodilator
3. -1:10,000= 1,000 mg: 10,000 mL»
   1 mg in 10 cc
   dose is 0.1-0.25 mg IV which is 1cc to 2.5 cc