Electrolytes

Question 1

For every 1 L of isotonic fluid given, how many cc stay intravascularly

Answer 1

250 cc or 250 ml

Question 2

What is the 4, 2, 1 rule for maintenance fluids? 

Answer 2

40 mL for first 10 kg
20 mL for second 10 kg
1 mL for remaining kg

So for a 75 kg person they would need 115 mL per hour for maintenance fluids  

Question 3

With normal kidney function, 10 mEq PO or IV increases K+ on average…

Answer 3

.10 mEq

Question 4

And the case of hypokalemia, always check…

Answer 4

Magnesium

Question 5

In the case of hyperkalemia, always check…

Answer 5

Hemolyzed blood sample, and order an EKG 

Question 6

Normal K+ level 

Answer 6

3.6-5.0

Question 7

K+ <2.5

Answer 7

Check for EKG changes, 80 mEq KCl, can use mix of IV and PO, recheck K+ after replaced 

Question 8

K+ 2.5-3.0

Answer 8

40 to 60 mEq KCl PO 

Question 9

K+ 3.1-3.5

Answer 9

20 to 40 mEq KCl PO 

Question 10

K+ of 5.1-6.0

Answer 10

Check EKG for changes, may need repeat K+ level and closer monitoring 

Question 11

K+ >6.1

Answer 11

• EKG
• Continuous telemetry monitoring
• Ca gluconate or CaCl (1-2 amps)
• Insulin 10 units IV x 1 + 1-2 amps D50

+/- sodium zirconium (lokelma)

+/- NaHCO3 (1-3 amps)

+/- Lasix 40 mg IV

+/- Dialysis

Question 12

Magnesium abnormality

Answer 12

Monitor of patient, having arrhythmias, persistent, hypokalemia, or alcohol/malnourished. Be conservative with renal insufficiency. 

Question 13

Mg < 1.0

Answer 13

4-8 g MgSO4 IV over 12-24 hrs
Recheck and repeat dosing as needed

Question 14

Mg 1.0-1.5

Answer 14

2-4 g MgSO4 IV over 4-12 hrs

Question 15

Mg 1.6-1.9

Answer 15

1-2 g MgSO4 IV over 1-2 hrs

Question 16

Phosphorus formulations

Answer 16

Oral: K-Phos (if K<4) or Neutra-Phos (equal K and Na) (if K<4) each with 250 mg (8 mmol)

IV: K-Phos (if K<4)(15-30 mmol) + 4.4 mEq/mL K or Na-Phos (15-30 mmol)

Question 17

Phos <1.4

Answer 17

45 mmol

Question 18

Phos 1.4-1.8

Answer 18

30 mmol

Question 19

Phos 1.9-2.5

Answer 19

15 mmol

Question 20

In the setting of persistent hypocalcemia, check…

Answer 20

Magnesium 

Question 21

And the setting of calcium abnormality, correct for…

Answer 21

Albumin
Ca= total Ca + 0.02 (40-albumin)

Question 22

Acutely symptomatic hypocalcemia

Answer 22

Initially correct with 1-2 g calcium gluconate infused over 10-20 minutes

Will only raise levels for a few hours so may need to start infusion 

Question 23

Mild asymptomatic hypocalcemia

Answer 23

Oral supplementation, use calcium carbonate, or calcium citrate, 1-2 g and divided doses 

Question 24

Calcium chloride is generally reserved as a…

Answer 24

Code blue medicine, central access preferred to deliver this medication