8. Fluids and electrolytes Flashcards
Describe etiology: Approach to Infant/Child with Dehydration (2)
- decreased intake: poor oral intake during acute illness, breastfeeding difficulties, eating disorders
- increased losses:
- common sites include GI tract (diarrhea, vomiting, bleeding)
- skin/mucous membranes (fever, burns, hemorrhage, stomatitis),
- urine (osmotic diuresis [e.g. hyperglycemia, DKA]
- diuretic therapy
- diabetes insipidus (DI)
- post-obstructive/post ATN recovery diuresis)
- and respiratory tract (tachypnea, bronchiolitis, pneumonia)
Describe management: Infant/Child with Dehydration (6)
- if suspect dehydration based on history (acute illness, decreased number of wet diapers, lethargy, changes in mental status, increased thirst, etc.), you must:
1. Determine degree of extracellular volume contraction
2. Determine the likely electrolyte disturbance- dependent on etiology of dehydration and type of fluid loss (isotonic vs. hypertonic vs. hypotonic)
- for moderate and severe dehydration, initial investigations should include urinalysis and blood work examining electrolyte (Na+, K+, Cl–), glucose, and acid-base (blood pH, pCO2, HCO3– disturbances), and impaired renal function (creatinine, BUN)
- Determine if the child requires PO or IV rehydration
- Return the child to a normal volume and electrolyte status by replacing current deficits and ongoing losses
- Provide the appropriate fluid and electrolyte maintenance daily requirements
- Continue to monitor fluid and electrolyte status
Describe: Body fluid compartments
Describe: Assessment of Degree of Extracellular Volume Contraction Based on Physical Exam (Table)
Describe: Electrolyte Content of Various Bodily Fluids
How to determine if the child requires PO or IV rehydration (3)
- dehydrated child must receive adequate fluid management, including replacement of ongoing losses and maintenance fluids
- oral rehydration therapy (ORT) indication: mild to moderate dehydration
- advantages: ⬇️ cost, no IV needed, no increase in incidence of iatrogenic hyper/hyponatremia, parental involvement in therapy
- indications for IV rehydration therapy: severe dehydration requiring close monitoring and frequent assessment of electrolytes, inability to tolerate ORT (e.g. vomiting, alteration in mental status, ileus, monosaccharide malabsorption, etc.), inability to provide ORT, failure of ORT in providing adequate rehydration (e.g. persistent diarrhea or vomiting)
Describe: Algorithm for deficit replacement and replacement of ongoing losses in the dehydrated child
Describe: Maintenance Fluid Requirements according to body weight
- 1-10kg
- 11-20kg
- >20kg
In children, all maintenance fluids should have a ___ component due to their higher risk of hypoglycemia, especially if they are NPO
- in children, all maintenance fluids should have a dextrose component due to their higher risk of hypoglycemia, especially if they are NPO
Name: Common IV fluid combinations used in pediatrics (5)
- newborn: D10W
- 1st mo of life: D5W/0.45 2 NS + KCl 20 mEq/L (only add KCl if voiding well)
- children
- without special considerations:
- D5W/NS + KCl 20 mEq/L – decreased risk of hyponatremia
- NS bolus for dehydration
- other options: D5W0.45%NS + KCl 20 mEq/L
Describe: Most important thing to remember when correcting Na+ aberrations due to fluid deficits (2)
- risk of cerebral edema with rapid rehydration with hypotonic or isotonic solutions (i.e. NS)
- therefore replace fluid slowly with close monitoring
- aim to adjust (increase or decrease) plasma [Na+] by no more than 12 mmol/L/d
Describe how to continue to monitor fluid and electrolyte status (3)
- accurate monitoring of daily fluid intake (PO and IV) and ongoing losses (urine output, diarrhea, emesis, drains)
- if child receiving >50% of maintenance fluids through IV, serum electrolyte values should be monitored daily and therapy adjusted accordingly
- avoid iatrogenic hyper/hyponatremia, keep the possibility of SIADH in mind
