The impact of different infusates on the serum sodium in a patient with hyponatremia can be calculated based on clinical and chemical measurements.
change in serum sodium in mmol/L following infusion of 1 liter of IV fluid =
= (((infusate sodium concentration in mmol/L) + (infusate potassium concentration in mmol/L)) - (patient's serum sodium concentration in mmol/L)) / ((total body water in liters) + 1)
|
Population |
Estimated Total Body Water in Liters |
|
children |
0.6 * (body weight in kg) |
|
nonelderly male |
0.6 * (body weight in kg) |
|
nonelderly female |
0.5 * (body weight in kg) |
|
elderly male |
0.5 * (body weight in kg) |
|
elderly female |
0.45 * (body weight in kg) |
where:
• Need to clarify if ideal body weight or actual body weight should be used.
|
Solution |
Sodium in mmol/L |
|
5% dextrose |
0 |
|
0.2% sodium chloride in 5% dextrose in water |
34 |
|
0.45% sodium chloride in water |
77 |
|
Ringer's lactate |
130 |
|
0.9% sodium chloride in water |
154 |
|
3% sodium chloride in water |
513 |
|
5% sodium chloride in water |
855 |
volume of IV fluid to infuse in mL =
= (target change in serum sodium to achieve in mmol/L) / (change in serum sodium in mmol/L per liter infusate) * 1000
rate to infuse IV fluid in mL/h =
= (volume to infuse in mL) / (time frame in hours)
Purpose: To estimate the impact of a fluid replacement infusion on the serum sodium.
Specialty: Endocrinology, Clinical Laboratory, Emergency Medicine, Critical Care
Objective: laboratory tests
ICD-10: E87.1,
