Dehydration

Maintenance fluid requirements

• 4cc/kg/hr for 0-10kg (or 100cc/kg/day)
• 2cc/kg/hr for 11-20kg (or 50cc/kg/day)
• 1cc/kg/hr for 21+kg (or 25cc/kg/day)

Maintenance electrolyte requirements

• Na: 2-4mmol/kg/day
• K: 1-2mmol/kg/day

	NS	½ NS	RL	D5W	D5 ½ NS	2/3 D5W 1/3 NS
[Na]	154	77	130	0	77	51
[K]	0	0	4	0	0	0
[Glucose] g/100ml	0	0	0	5	5	3.33

* 2/3,1/3 with potassium is a good fluid for maintenance
* D5 ½ NS is a good fluid if dehydrated

History

• Losses (vomit, diarrhea, bleeding, sweating)
• Duration, quantity, frequency
• Amount of intake (oral, IV)
• Type of replacement
• Frequency of urination
• Change in weight, change in activity level

Physical exam

Physical signs	Mild	Moderate	Severe
CVS
HR	Normal	↑	↑↑↑
BP	Normal	Normal – slight ortho drop	Orthostatic drop – ↓
JVP	Normal	↓	↓↓↓
Capillary refill	Normal	2 – 4 seconds	> 4 seconds
Skin
Colour	Normal	Pale	Mottled
Turgor	Normal	1 – 2 seconds	> 2 seconds
Fontanelle	Normal	Slight ↓	Sunken
Mucous membranes	Normal	Dry	Parched
Tears	Normal	↓	Absent
U/O	↓	↓↓	Oliguria/Anuria
Thirst	↑	↑↑	↑↑↑
Weight loss	3 – 5%	6 – 10%	> 10%
CNS	Normal	Irritable	Lethargic

 

• See table above

Lab tests

• Lytes, BUN, creatinine, glucose
• U/A
• Serum and urine osmolality
• Urine lytes
• ABG if severe acidosis

Management

• Most common in pediatrics is GI losses and poor intake
• Ideally ORAL rehydration should be attempted (Pedialyte, Lytren – not juice/Gatorade because too much glucose will cause more water loss due to osmosis)
  • Mild: 10cc/kg bolus over 1 hr, then 10cc/kg/hr plus 10cc/kg/stool –> reassess in 4-6 hr
  • Moderate: 20cc/kg bolus over 1 hr, then 20cc/kg/hr plus 10cc/kg/stool –> reassess in 4-6 hr
  • If moderate or severe dehydration, the patient will require IV rehydration
    • Serum Na 130-150; CVS and renal normal
      • Bolus NS 10-20cc/kg over 1 hr
      • Maintenance + Deficit + Ongoing losses (D5 ½ NS + 40mmol KCl/L add KCl only after child has voided)
      • Deficit = H2O (%body weight), Na 4-8mmol/kg, K 2-4mmol/kg
      • Replace ½ deficit over first 8 hr along with maintenance, and the remainder over the next 16 hr

On your OSCE exam write FULL admission orders (DAT (breastfeeding ad lib), AAT, VSR…), also don’t forget to put guidelines for vitals for housestaff to be called, and accurate ins and outs. Date, time and sign your order… also put your pager number.