Question

a 46 lb. postoperative patient needs fluids at 75 ml/kg/day with lidocaine (2%) at 30ug/kg/min, ketamine (100 mg/ml) at 5 ug/kg/min, and morpine (10 mg/ml) at 2.5 (ug/kg/min).

a: what is the rate of fluids per hour

b: how many militers of medication to add to 1 L bag:

of lidocaine ? of Ketamine? of morphine??

PLEASE ANSWER ALL PARTS AND SHOW WORK

Answer 1

a .The person needs 75ml/kg/ day .

Now , 46 lbs is equal to 20.8 kgs.

Therefore, per day , the fluid required is 75 x 20.8 = 1560 ml or 1.56 L . This is the fluid rate in a day .

For an hour , the fluid rate is - 1560/24 = 65 ml/hour .

b. We have lidocaine concentration as 2% . Which means 2g is present in 100 ml solution.

Now the total lidocaine amount taken per day is

- 30 x 10 -6 x 20.8 x 24 x 60 ( we have the rate per minute )

- 0.89 g / day .

If we have 2g in 100 ml , then 0.89 will be there in

- 100 x0.89/ 2= 44.5 ml /day .

Lastly, this volume is according to 1.56 litres of fluid .

So for 1 l fluid , the volume in ml will be

- 44.5 /1.56 = 28.5 ml.

For Ketamine , per day infusion is

5 x 10 -6 x 20.8 x 24 x 60

= 0.15g /day.

Now we have 0.1g / 1ml concentration .

So 0.15g will be present in

= 0.15 /0.1 = 1.5 ml

Again , for 1 liter , the volume of ketamine is

= 1.5 /1.56 = 0.9 ml .

For morphine, per day amount is

= 2.5x 20.8 x 24 x60 x 10 -6

=0.074 g /day

= 74 mg/day .

Now we have 10mg / ml

So 74 mg will be present in

= 74/10 = 7.4 ml

Again , the volume in 1 liter will be

7.4 / 1.56 = 4.74 ml.