Management of Dehydration

Question 1

What are the two steps involved in repletion therapy in children?

Answer 1

1) Emergent correction of moderate to severe hypovolemia, ensuring a return of adequate intravascular volume and avoiding tissue damage
- Primarily done by I.V.

2) Finished repletion of fluids and electrolyte losses
- The second step is the only step required in mild to moderate hypovolemia
- More commonly done by oral rehydration

Question 2

Severe hypovolemia is associated with a depletion of what percentage of volume?

Answer 2

10% or higher

Question 3

What symptoms are seen in severe hypovolemia

Answer 3

• Cap refill > 3 seconds
• Cool and mottled extremity
• Lethargy
• Hypotension and shock (late signs)

Question 4

What is the initial management of severe hypovolemia

Answer 4

• Rapid infusion of I.V. isotonic saline
• 20mL/kg
• Reassess frequently and continue until not severe

Question 5

What fluid is used in the management of severe hypovolemia and why?

Answer 5

• Isotonic Saline (0.9%)

- Using hypo or hypertonic solution for rapid infusions can result in electrolyte abnormalities and is not recommended

Question 6

A patient with tachycardia, weak pulses, orthostatic hypotension and dry mucous membranes likely has what level of dehydration?

Answer 6

• Moderate (5-10%)

Question 7

A patient with dry mucous membranes, oliguria, and who is thirsty and irritable likely has what level of dehydration?

Answer 7

• Moderate (5-10%)

Question 8

A patient who is thirsty, with palpable pulses, moist mucous membranes likely has what level of dehydration?

Answer 8

• Mild (under 5%)

Question 9

What results would you expect to see WRT BUN and Creatinine in a dehydrated patient?

Answer 9

• Disproportionate increase in BUN compared to creatinine
• Low GFR from low volume allows more time for BUN to be reabsorbed into the blood, creatinine is not reabsorbed and not affected outside of what would be expected from lower GFR

Question 10

How do you calculate a child’s fluid deficit?

Answer 10

1) Estimate the level of dehydration
- Mild (5%)
- Moderate (10%)
- Severe (15%)
2) Multiply estimated level of dehydration by the patients weight

Ex: Moderate dehydration in 10kg patient
- 10kg x 10% = 1L deficit

Question 11

Explain in detail how you would manage a 20kg patient with 15% dehydration

Answer 11

1) Category - severe. Requires I.V. rapid volume repletion initially
- Use 20cc/kg NS
- Reassess and repeat as needed

2) Calculate 24hr fluid need
- maintenance (100-50-20 rule)
= 10 x 100 = 1000cc
+ 10 x 50 = 500cc
= 1.5L
- Deficit (15% dehyrated x 20kg)
= 0.15 x 20
= 3L
Total for 24hr = 4.5 L

3) Subtract isotonic fluid already administered from the 24hr total
- Administer remaining volume using D5 1/2 NS + 20mE1/L KCL
- Typical rate 1.25-1.5x maintenance

4) Replace ongoing losses as they occur

Question 12

Correction of a long standing hyponatremia should not exceed what rate?

Answer 12

> 12 mEq /L per 24 hours

- Due to risk of central pontine myelinolysis

Question 13

What can cause hyponatremic dehydration?

Answer 13

Diarrhea compined with hypotonic volume repletion (ex. water)

Question 14

What can cause hypertonic dehydration?

Answer 14

• Inability to take in fluids (lack of access, neurologic impairment, irritractable vomiting or anorexia)

Question 15

When can oral rehydration therapy be performed?

Answer 15

• Mild to moderate dehydration from any cause that can be treated effectively with simple, oral rehydration (ie. couldn’t with severe vomiting)