Calculation of maintenance fluids

How many mL are in 1 oz?

30 mL

What is the minimal urine output for an adult on maintenance IV?

30 mL/hr (0.5 cc/kg/hr)

How many mL are in 1 tsp?

5 mL

What is the common adult maintenance fluid?

D5 1/2 NS with 20 mEq KCl/L

What is the major intracellular cation?

K+

What is the 100/50/20 rule?

Maintenance IV fluids for a 24-hour period: 100 mL/kg for the first 10 kg 50 mL/kg for the next 10 kg 20 mL/kg for every kg over 20 (divide by 24 for hourly rate)

What is the 4/2/1 rule?

Maintenance IV fluids for hourly rate: 4 mL/kg for the first 10 kg 2 mL/kg for the next 10 kg 1 mL/kg for every kg over 20

What is the major extracellular cation?

Na+

Why should sugar (dextrose) be added to maintenance fluid?

To inhbit muscle breakdown

What is the best way to assess fluid status?

Urine output (unless the patient has cardiac or renal dysfunction, in which case central venous pressure or wedge pressure is often used)

What is the maintenance fluid for a 70-kg man using 100/50/20?

Using 100/50/20: 100 x 10 kg = 1000 50 x 10 kg = 500 20 x 50 kg = 1000 Total = 2500 Divided by 24 hours = 104 mL/hr maintenance rate

What is the maintenance fluid for a 70-kg man using 4/2/1?

Using 4/2/1: 4 x 10 kg = 40 2 x 10 kg = 20 1 x 50 kg = 50 Total = 110 mL/hr maintenance rate