Question

Specifications for lactated Ringer’s solution, which is used for intravenous (IV) injections, are as follows to reach 100. mL of solution:

285–315 mg Na1

14.1–17.3 mg K1

4.9–6.0 mg Ca21

368–408 mg Cl2

231–261 mg lactate, C₃H₅O₃

2

a. Specify the amount of NaCl, KCl, CaCl₂? 2H₂O, and NaC₃H₅O₃ needed to prepare 100. mL lactated Ringer’s solution.

b. What is the range of the osmotic pressure of the solution at 37˚ C, given the preceding specifications?

Short answer

Sodium chloride content = 0.014 g/ml

Potassium chloride content = 0.007 g/ml

Calcium chloride content = 0.00024 g/ml

Chloride content = 0.0018 g/ml

Osmotic pressure = 0.294 atm

Step-by-step solution

Step 1:

Nac = b/1000 x 200/V x 50/2 x 100

Same equation is used for Ca, Cl₂

Nac Is content of sodium.

b is concentration of sodium = 285 x 10 ^-3/ 100 = 0.0028

Nac = 0.0028/1000 x 200/100 x 50/2 x 100 = 28 x 10 ^-7 x 2 x 25 x 100 = 0.014 g/ml

Kc = 14.1 x 10^-3 /100 = 0.0014

Kc = 0.0014/1000 x 200/100 x 50/2 x 100 = 14 x 10 ^-7 x 2 x 25 x 100 = 0.007

Cac = 4.9 x 10^-3 /100 = 4.9 x 10 ^-5

Cac = 4.9 x 10 ^-5 /1000 x 200/100 x 50/2 x 100 = 4.9 x 10^-8 x 2 x 25 x 100 = 0.00024

Clc = 368 x 10^-3 /100 = 0.0036

Clc = 0.0036/1000 x 200/100 x 50/2 x 100 = 0.036 x 2 x 25/1000 = 0.0018

Step 2:

For finding the osmotic pressure of lactate solution

First have to calculate the concentration as follows:

231 mg of lactate = 231 x 10 ^-3/ 100 = 0.00231

Lactate concentration = 0.00231/1000 x 200/100 x 50/2 x 100 = 0.000231x 2 x 25 = 0.0115

Gas constant = 0.08206 L.atm/kmol

Temperature = 37 ˚C = 37+ 273 = 310K

Osmotic pressure= CRT

= 0.0115 x 0.08206 x 310 = 0.294 atm