Fluids&Lytes Pediatric
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Transcript of Fluids&Lytes Pediatric
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Fluids & Electrolytes
Pediatric Emergency Medicine
Boston Medical Center
Boston University School of Medicine
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Objectives
To discuss:
Maintenance Fluids and Electrolyte Requirements
Types of Dehydration
Management of Dehydration
Electrolyte Abnormalities
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Composition of Body
Compartments
Total Body Water (TBW)= 50-75% of Total Body
Mass TBW = Intracellular Fluid (ICF) + Extracellular Fluid (ECF)
ICF = 2/3 of TBW
ECF = 1/3 of TBW -- 25% of body weight
ECF = Plasma (intravascular) + Interstitial fluid
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Body Water Compartments
Related to Age
0
10
20
30
40
50
60
70
80
0 years 1 year 10 years 20 years
TBW
ICF
ECF
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Regulation of Body Fluids and
Electrolytes Mechanism to Regulate ECF volume
Anti-Diuretic Hormone (ADH)
Kidney = Increase water reabsorption
ADH secretion is regulated by tonicity of body
fluids
Thirst
Not physiological stimulated until plasma
osmolality is >290
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Regulation of Body Fluids and
ElectrolytesAldosterone
Released from the adrenal cortex
Decrease circulating volume
Stimulation by Renin-Angiotensin Aldosterone axis
Increase plasma K
Enhanced renal reabsorption of Na in
exchange for K (>Na = expansion of ECF)
Atrial Natriuretic Factor Secreated by the cardiac atrium in response to
atrial dilatation (regulates blood volume)
Inhibits Renin secretion
Increase GFR and Na excretion
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4cc, 2cc, 1cc rule
4 cc for the first 10 kg
2 cc for the next 10 kg
1 cc for each kg after
Example:
27 kg child
4 cc for the first 10 kg = 40cc
2 cc for the next 10 kg = 20cc
1 cc for each kg after = 7 cc
67 cc/hr
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Maintenance Requirements
Maintenance Fluids: weight dependent& age dependent:
(NS =0.9% Saline =154 meq Na/liter)
age >2 -3 years: D5 0.5 NS + 20 meqKCl/liter
Up to age 2-3 years: D5 0.2 NS + 20 meqKCl/liter
D5 = 50 gm/liter = 5 g/dl
Newborns often require D10 = 100 gm/liter = 10gm/dl
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Estimation of Dehydration
Mild Moderate Severe
Weight Loss 3-5% 6-9% >10%
Blood pressure Normal Orthostatic Shock
Pulse Normal Increase Tachycardic
Behavior Normal Irritable Lethargic
Membranes Moist Dry Parched
Tears Present Decrease Absent
Cap. Refill 2 seconds 2-4 seconds >4 seconds
Urine SG >1.020 >1.030 Oliguria
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Management of Dehydration
General Principles:
Supply Maintenance Requirements
Correct volume and electrolyte deficit
Replace ongoing abnormal losses
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Management of Dehydration
Oral Rehydration:
Effective for mild and some moderate
dehydrations Child may be able to tolerate PO intake
Small aliquots as tolerated Mild: 50 cc/kg over 4 hours
Moderate: 100 cc/kg over 4 hours
2 types of oral solution Maintenance
Rehydration
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Commercial Oral Solutions
Na mEq/L K mEq/L Cl mEq/L Base CHO %
Maintenance
Reosol 50 20 50 Citrate Glucose 2
Ricelyte 50 25 45 Citrate Rice syrup 3
Pedialyte 45 20 35 Citrate Glucose 2.5
Rehydration
Rehydralyte 75 20 65 Citrate Glucose 2.5
W.H.OFor cholera use
90 20 80 HCO3 Glucose 2
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Management of Dehydration:
IV Replacement of Fluid Deficit Based on %
Dehydration:
Example: 5 kg child who is 6% dehydrated: 5 x60cc/kg fluid deficit (cc) = wt x % dehydration
fluid deficit (cc) = wt in kg (1000cc/kg) x (1/100)
estimate of dehydration fluid deficit (cc) = wt x 10 x estimate of dehydration
fluid deficit (cc) = 5 x 10 x 6
fluid deficit (cc) = 300 cc
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Management of Dehydration:
IV Initial: NS or LR 20 cc/kg Bolus in first hour
Then Remainder of Deficit
In previous example: total fluid deficit = 300ccfor 5 kg child who is 6% dehydrated = 60cc/kg
Replacement:
first hour: 20 cc/kg = 20 x 5 = 100 cc
replace the rest: 40 cc/kg or 300 - 100 = 200 cc The type of fluid used and the rate of infusion
depends on the age and Na status of the patient:
for isonatremic dehydration: correct deficits of
next 7 hours
200cc over 7 hours = 28 cc/hr
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Hyponatremia
Predisposing Factors
Diabetes mellitus (hyperglycemia)
Cystic fibrosis
CNS disorders ( SIADH)
Gastroenteritis
Excessive water intake (formula dilution) Diuretics (thiazides and furosemide)
Renal disease
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Hyponatremia
Hyponatremic Dehydration
Hypovolemic Hyponatremic Dehydration
High urine output and Na excretion
Increase in atrial natriuretic factor
Euvolemic Hyponatremic Dehydration
ADH mediated water retention Hypervolemic Hyponatremic Dehydration
Edematous disorder (nephrotic syndrome,
CHF, cirrhosis)
Water intoxication
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Hyponatremia
Acute Hyponatremia (
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Hyponatremia
Chronic Hyponatremia (>48 hours)
Lethargy
Confusion
Muscle cramps
Neurologic Impairment
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Hyponatremia
Management Na Deficit:
Na Deficit = (Na Desired - Na observed) x 0.6x body weight(kg)
Replace half in first 8 hours and the rest in thefollowing 16 hours
Rise in serum Na should not exceed 2 mEq/L/h toprevent Central Pontine Myelinolysis (? Existencein children)
In cases of severe hyponatremia (
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Hypernatremia
Hypernatremia leads to hypertonicity
Increase secretion of ADH
Increase thirst
Patients at risk
Inability to secrete or respond to ADH
No access to water
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Hypernatremia
Etiology
Pure water depletion
Diabetes insipidus (Central or Nephrogenic) Sodium excess
Salt poisoning (PO or IV)
Water depletion exceeding Na depletion Diarrhea, vomiting, decrease fluid intake
Pharmacologic agents
Lithium, Cyclophosphamide, Cisplatin
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Hypernatremia
Signs and symptoms
Disturbances of consciousness
Lethargy or Confusion
Neuromuscular Irritability
Muscle twitching, hyperreflexia
Convulsions Hyperthermia
Skin may feel thick or doughy
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Hypernatremia Management
Normal Saline or Ringer lactate to restore volume
Hypotonic solution (D5 1/4 NS) to correct calculated
deficit over 48 hours Water Deficit
Normal body H20 - Current body H20
Current body water 0.6 x body weight (kg) x Normal Na/Observed Na
Normal Body water 0.6 x body weight (kg)
Decrease Na concentration at a rate of 0.5 mEq/hror ~ 10 mEq/day: Faster correction can result in
Cerebral Edema
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Potassium
Most abundant intracellular cation
Normal serum values 3.5-5.5 mEq
Abnormalities of serum K are potentially life-
threatening due to effect in cardiac function
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Hypokalemia
Diagnosis
Symptoms
Arrhythmias Neuromuscular excitability (hyporreflexia, paralysis)
Gastrointestinal (decreased peristalsis or ileus)
Serum K < 3mEq/L
ECG:
Flat T waves
Short P-R interval and QRS
U waves
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Hypokalemia
Nutritional GI Loss Renal Loss Endocrine
Poor intake Diarrhea Renal tubular acidosis Insulin therapy
IVF low in K Vomiting Chronic renal disease Glucose therapy
Anorexia Malabsorbtion Fanconi's syndrome DKAIntestinal fistula Gentamicin, Hyperaldosteronism
Laxatives Amphotericin Adrenal adenomas
Enemas Diuretics Mineralocorticoids
Bartter's syndrome
Bartters syndrome: Hypereninemia and hyperaldosteronism
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Hypokalemia
Management:
Cardiac Arrhythmias or Muscle Weakness
KCl IV (cardiac monitor)
PO K - Depend of etiology
Hypophoshatemia = KPO4
Metabolic acidosis = KCl
Renal tubular acidosis = K citrate
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Hyperkalemia
Differential Diagnosis
Pseudohyperkalemia - from blood hemolysis
Metabolic Acidosis
Chronic Renal Failure
Congenital Adrenal Hyperplasia
Females = Usually Dx at birth - AmbiguousGenitalia
Males = Dehydration, hyponatremia, hyperkalemia
Medications
ACE inhibitors and NSAIDs
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Hyperkalemia
Diagnosis:
Symptoms
Cardiac Arrhythmias Paresthesias
Muscle weakness or paralysis
ECG
Peaked T waves
Short QT interval (K>6 mEq)
Depressed ST segment
Wide QRS (K>8 mEq)
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Hyperkalemia
Management
Close cardiac monitoring
Life -threatening hyperkalmia Intravenous Calcium - rapid onset, duration< 30 min
NaHCO3 or glucose and insulin
Ion exchange resins Sodium polystyrene sulfonate (Kayexelate)
PO or Enema
Hemodyalisis