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Fluids & Electrolytes Pediatric Emergency Medicine Boston Medical Center Boston University School of Medicine.

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Presentation on theme: "Fluids & Electrolytes Pediatric Emergency Medicine Boston Medical Center Boston University School of Medicine."— Presentation transcript:

1 Fluids & Electrolytes Pediatric Emergency Medicine Boston Medical Center Boston University School of Medicine

2 Objectives  To discuss:  Maintenance Fluids and Electrolyte Requirements  Types of Dehydration  Management of Dehydration  Electrolyte Abnormalities

3 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

4 Body Water Compartments Related to Age

5 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

6 Regulation of Body Fluids and Electrolytes  Aldosterone 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

7 Daily Maintenance Requirements

8 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

9 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 meq KCl/liter  Up to age 2-3 years: D5 0.2 NS + 20 meq KCl/liter D5 = 50 gm/liter = 5 g/dl Newborns often require D10 = 100 gm/liter = 10 gm/dl

10 Dehydration  Epidemiology:  One of the most common medical problems  In the U.S. - 10% of all pediatric admissions  Worldwide, over 3 million children under 5 years die from dehydration

11 Estimation of Dehydration

12 Dehydration  Classification  Isotonic Serum Sodium mEq  Hypotonic Serum Sodium < 130 mEq  Hypertonic Serum Sodium >150 mEq

13 Management of Dehydration  General Principles:  Supply Maintenance Requirements  Correct volume and electrolyte deficit  Replace ongoing abnormal losses

14 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

15 Commercial Oral Solutions

16 Management of Dehydration: IV  Replacement of Fluid Deficit Based on % Dehydration :  Example: 5 kg child who is 6% dehydrated: 5 x 60cc/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

17 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 = 300cc for 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 = 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

18 Hyponatremia  Predisposing Factors  Diabetes mellitus (hyperglycemia)  Cystic fibrosis  CNS disorders ( SIADH)  Gastroenteritis  Excessive water intake (formula dilution)  Diuretics (thiazides and furosemide)  Renal disease

19 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

20 Hyponatremia  Acute Hyponatremia (<24 hours)  Early Onset (Serum Sodium <125 meq/L) Nausea Vomiting Headache  Later or Severe (Serum Sodium <120 meq/L) Seizure Coma Respiratory arrest

21 Hyponatremia  Chronic Hyponatremia (>48 hours)  Lethargy  Confusion  Muscle cramps  Neurologic Impairment

22 Hyponatremia  Management  Na Deficit: Na Deficit = (Na Desired - Na observed) x 0.6 x body weight(kg)  Replace half in first 8 hours and the rest in the following 16 hours  Rise in serum Na should not exceed 2 mEq/L/h to prevent Central Pontine Myelinolysis (? Existence in children)  In cases of severe hyponatremia (<120 mEq) with CNS symptoms: 3% NaCl 3-5 ml/kg IV push for hyponatremia induced seizures –6 ml/kg of NaCl will raise serum Na by 5 mEq/L

23 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

24 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

25 Hypernatremia  Signs and symptoms  Disturbances of consciousness Lethargy or Confusion  Neuromuscular Irritability Muscle twitching, hyperreflexia  Convulsions  Hyperthermia Skin may feel thick or doughy

26 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/hr or ~ 10 mEq/day: Faster correction can result in Cerebral Edema

27 Potassium  Most abundant intracellular cation  Normal serum values mEq  Abnormalities of serum K are potentially life- threatening due to effect in cardiac function

28 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

29 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 DKA Intestinal fistula Gentamicin, Hyperaldosteronism Laxatives Amphotericin Adrenal adenomas Enemas Diuretics Mineralocorticoids Bartter's syndrome Bartter’s syndrome: Hypereninemia and hyperaldosteronism

30 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

31 Hyperkalemia  Differential Diagnosis  Pseudohyperkalemia - from blood hemolysis  Metabolic Acidosis  Chronic Renal Failure  Congenital Adrenal Hyperplasia Females = Usually Dx at birth - Ambiguous Genitalia Males = Dehydration, hyponatremia, hyperkalemia  Medications ACE inhibitors and NSAID’s

32 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)

33 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


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