Fluid and electrolyte therapy
Done by:Mohammed Samier Supervised by:Dr.Hala
Al-Nahrain university/college of medicine IRAQ/BAGHDAD
I.V fluid therapy:-• Indications:-1-severe dehydration2-mild to moderate dehydration if there is:- *diarrhea >100 cc/hr *abdominal distension due to paralytic ilius or
gastric distention. *comatose patient. *repeated vomiting. *patient refused oral route.
Fluid therapyThere are two components to fluid therapy: • Maintenance therapy
• Replacement therapy
Maintenance therapy:-• replaces the ongoing losses of water and electrolytes under
normal physiologic conditions via urine, sweat, respiration, and stool.
• Measured according to body weight;Body weight(kg) Volume per day Hourly rate
0-10 100ml/kg 4 ml/kg/hr
11-20 1000 ml+50 ml/kg for each 1kg >10 kg
40 ml/hr +2 ml/kg/hr*(wt-10)
>20 1500 ml +20 ml/kg for each 1 kg >20kg
60 ml/hr+1 ml /kg/hr *(wt-20)
Maintenance requirements of electrolyte:• 2-3 mEq/kg/day of sodium• 1-2 mEq/kg/day of potassium. • Maintenance fluids 5% dextrose (D5),1/2,1/4 and 1/5 glucose saline• Children weighing less than about 20 to 25 kg do
best with the solution containing quarter NS because of their high water needs per kilogram.
• larger children and adults may receive the solution with half NS.
• The glucose in maintenance fluids provides approximately 20% of the normal caloric needs of the patient.
• This percentage is enough 1. to prevent the development of starvation
ketoacidosis and2. diminishes the protein degradation that would
occur if the patient received no calories. • avoiding the administration of hypotonic fluids,
which may cause hemolysis
• a child on maintenance IV fluids loses 0.5% to 1% of real weight each day because . Maintenance fluids do not provide adequate calories, protein, fat, minerals, or vitamins.
• The maximum total fluid per day is normally 2400 mL.
• The maximum fluid rate is normally 100 mL/hr.
Childs' requirment depend on:1-age2-body weight 3-degree of activity4-tempreture
Conditions that decrease requirment by 30-45 % include:-• Anuria or extreme oliguria• Excessive ADH release(meningitis)• Congestive heart failure• But hypothyroidism decrease
requirement by 10-20 %
Requirement increased in:
• Skin Radiant warmer Phototherapy Fever Sweat Burns• Lungs Tachypnea Tracheostomy • Gastrointestinal Diarrhea Emesis Nasogastric suction • Renal Polyuria • Miscellaneous Surgical drain Third space losses
Heat stress:-• Fever leads to a predictable increase in
insensible losses, causing a 10% to 15% increase in maintenance water needs for each 1°C increase in temperature greater than 38°C.
e.g:-12 kg ,39c =1100+(1100*10%) =1100+110 =1210 ml
Goals of Maintenance Fluids
1. Prevent dehydration 2. Prevent electrolyte disorders 3. Prevent ketoacidosis 4. Prevent protein degradation
Replacement therapy
• corrects any existing water and electrolyte deficits.
• These deficits can result from gastrointestinal,
urinary, or skin losses, bleeding, and third-space sequestration.
Calculation of deficit:• Water deficit(L)=degree of dehydration*B.wt• Na deficit=water D in litter*80 mEq/L• K deficit=water D*30mEq/Le.g:-12 kg ,10% dehydrated?Water D=10% *12=1.2LNa D=1.2 *80 =96 mEq/LK D=1.2*30 =36 mEq/L
Adjusting Fluid Therapy for Gastrointestinal Losses
Average Composition Approach to ReplacementDiarrhea Replacement of Ongoing Stool
LossesSodium: 55 mEq/L Solution: 5% dextrose in ¼ normal
saline + 15 mEq/L bicarbonate + 25 mEq/L potassium chloride
Potassium: 25 mEq/L Replace stool mL/mL every 1-6 hr
Bicarbonate: 15 mEq/L
Gastric Fluid Replacement of Ongoing gastric Losses
Sodium: 60 mEq/L Solution: 5% dextrose in half normal saline + 10 mEq/L potassium chloride
Potassium: 10 mEq/L Replace output mL/mL every 1-6 hr
Chloride: 90 mEq/L
• mild moderate Severe
Infant 5% 10% 15%
Infant/young children
Thirsty; alert; restless
Thirsty; restless or lethargic but irritable or drowsy
Drowsy, cold, sweaty, cyanotic extremities; may be comatose
Older children Thirsty; alert; restless
Thirsty; alert (usually)
Usually conscious (but at reduced level), apprehensive; cold, sweaty, cyanotic extremities; wrinkled skin on fingers and toes; muscle cramps
dehydration
Signs & Symptoms
Severe Moderate Mild
Tachycardia Present Present Absent
Palpable pulses Decreased Present (weak) Present
Blood pressure Hypotension Orthostatic hypotension
Normal
Cutaneous perfusion
Reduced & mottled
Normal Normal
Skin turgor Reduced Slight reduction Normal
Fontanel Sunken Slightly depressed
Normal
Mucous membrane
Very dry Dry Moist
Tears Absent Present or absent
Present
Respirations Deep & rapid Deep, may be rapid
Normal
Urine output Anuria & severe oliguria
Oliguria Normal
Fluid Management of Dehydration
Restore intravascular volumeNormal saline: 20 mL/kg over 20 min (repeat until intravascular volume restored)
Calculate 24-hr water needsCalculate maintenance water, calculate deficit water
Calculate 24-hr electrolyte needsCalculate maintenance Na & K, calculate deficit Na & K
Select an appropriate fluid (based on total water & electrolyte needs)Administer half the calculated fluid during the first 8 hrs, first subtracting any boluses from this amountAdminister the remainder over the next 16 hrs
Replace ongoing losses as they occur
Example:-12 kg baby presented with severe dehydration.• M=10*100+2*50 =1100 ml• D=degree of dehydration*B.wt D=150*12=1800• 1st 8 hr=1/2M+1/2D =550+900 =1450ml1st hr10-30 ml/kg =20*12=240mlNext 7 hr=1450-240 =1210ml• Next 16 hr =1/2M+1/2D =1450 ml• Rate=44 ml/hr
Hyponatremia: Na<130 mEq/L• Hyponatremia usually associated with
hyposomolality.• Types of hyponatremia
1. Pseudohyponatremia(lab artifact)2. Hyperosmolality(hyperglycemia,mannitol)3. Hypovolemic(extrarenal,renal)4. Euvolemic(SIADH, hypothyroidism, water
intoxication)5. Hypervolemic(CHF,cirrhosis,nephrotic syndrome,
RF,hypoalbominemia)
Clinical manifestations:-• Lethergy, apathy, disorientation, muscle cramps,
anorexia, and agitation• Reduced mental status, decreased deep tendon
reflexes, hypothermia, seizures, pseudobulbar palsies.
• More severe symptoms associated with acute decrease of Na level below 120 mEq/L
• Chronic decrease to 110 mEq/L may be asymptomatic.
Treatment: 1-acute or symptomatic hyponatremia:
Initial therapy should be calculated to raise Na level to 120 mEq/l
Subsequent correction to 130 mEq/l can be carried out over the next 24-36 hr
Avoid rapid correction over 130 mEq/l because this will lead to central pontine myelinolysis
Na level should not be raised or lowered more rapidly than 12 mEq/24 hr
Hypertonic saline 3% can be used Each milliliter of 3% sodium chloride per kilogram increases
the serum sodium by approximately 1 mEq/L.
•Fluid restriction and NaCl (NS)
required Na mEq=(desired Na-current Na)*0.6*wt
•in symptomatic hyponatremia without edema diuretics can be
used.
volume of diuresis needed to correct hyponatremia may be
calculated by the following equation:
TBW=0.6*wt(kg)
excess water=TBW-current Na/desired Na*TBW
Hyponatremic dehydration • occurs in children who have diarrhea and
consume a hypotonic fluid (water or diluted formula).
• Volume depletion stimulates secretion of ADH, preventing the water excretion.
• some patients develop symptoms, predominantly neurologic.
Treatment of hyponatremic dehydration
• Need water and Na replacement• Required mEq=(desired Na-current
Na)*0.6*wt(kg)e.g:-12 kg ,severely dehydrated ,Na level 110
mEq/l ?Fluid requirement=1800 mlmEq=(120-110)*0.6*12 =72 mEq• Given over 24-36 hr
• Clinical manifestations:
Most children with hypernatremia are dehydrated and have the
typical signs and symptoms of dehydration.
•Blood pressure and urine output are maintained, and
hypernatremic infants are less symptomatic initially and
potentially become more dehydrated before seeking medical
attention.
•the pinched abdominal skin of a dehydrated, hypernatremic
infant has a "doughy" feel.
Hpernatremia:- Na>150 mEq/l
–Hypernatremia, even without dehydration, causes CNS symptoms that tend to parallel the degree of sodium elevation and the acuity of the increase.
–Patients are irritable, restless, weak, and lethargic. –Some infants have a high-pitched cry and hyperpnea. –Alert patients are very thirsty, although nausea may
be present.– Hypernatremia causes fever, although many patients
have an underlying process that contributes to the fever. –Hypernatremia is associated with hyperglycemia and
mild hypocalcemia; the mechanisms are unknown
Brain hemorrhage is the most devastating consequence of hypernatremia. As the extracellular osmolality increases, water moves out of brain cells, resulting in a decrease in brain volume. This decrease in volume can result in tearing of intracerebral veins and bridging blood vessels as the brain moves away from the skull and the meninges. Patients may have subarachnoid, subdural, and parenchymal hemorrhage.
Seizures and coma are possible squeal of the hemorrhage, although seizures are more common during treatment.
The cerebrospinal fluid protein is often elevated in infants with significant hypernatremia, probably owing to leakage from damaged blood vessels
Treatment:
• Hypernatremia should be corrected slowly over 24-36 hr.
• Lowering Na level not > 12 mEq/L/day because rapid correction lead to cerebral edema.
• normal TBW=0.6*normal wt(kg) current TBW=TBW*normal Na/current Na water deficit=normal TBW-current TBW
Hypernatremic dehydration • is usually a consequence of an inability to
taken fluid, owing to a lack of access, a poor thirst mechanism (neurologic impairment), intractable emesis, or anorexia.
• Children with hypernatremic dehydration often appear less ill than children with a similar degree of isotonic dehydration.
• Children with hypernatremic dehydration are often lethargic and irritable when touched.
Hypokalemia: K < 3.0 mEq/L• Clinical manifestations: ileus, muscle weakness, polyuria, polydipsia,
areflexic paralysis.• ECG changes include:i. ST depressionii. T wave reductioniii. Presence of U wave
Factors that influence the therapy of hypokalemia include:
the potassium level clinical symptoms, renal function, presence of transcellular shifts of
potassium(DKA,metabolic acidosis) ongoing losses patient's ability to tolerate oral potassium
Treatment:• Gastrointestinal or renal causesKCl• Does of 0.5-1 mEq/kg given over 1 hr• The adult maximum dose is 40 mEq.
Hyperkalemia: K >5.5 mEq/l
• Clinical manifestations paresthesia ,weakness ,flaccid paralysis ,cardiac
arrhythmia.• ECG changes1. (5.5-7 mEq/l)peaked or tented T-wave.2. (7-8 mEq/l)prolonged PR, ST depression, initial
widening of the QRS complex.3. ( >8mEq/l)flat P wave, wide QRS.4. no treatment lead to asystole or ventricular
fibrilation.
Treatment Rapidly decrease the risk of life-threatening arrhythmias - Shift potassium intracellularly Sodium bicarbonate administration (IV) Insulin + glucose (IV) Glucose ( 0.5 g/kg insulin 0.1 U/kg IV over 30
minutes) β-Agonist - Cardiac membrane stabilization IV calcium gluconate 1 mL/kg of 10% solution IV over 3-5 minutes
Remove potassium from the body Loop diuretic (IV or PO) Sodium polystyrene (PO or rectal) Dialysis
AGENT MECHANISM DOSE PRECAUTIONS/COMPLICATIONS
Kayexalate Exchange K+ across colonic mucosa
1-2 g/kg oraly or PR Hypernatremia, constipation
Glucose and insulin Cell uptake Glucose 0.5 g/kg insulin 0.1 U/kg IV over 30 minutes
Hypoglycemia, hypophosphatemia
Sodium bicarbonate Cell uptake 0.5 meq/Kg IV over 10-15 minutes
Hypernatremia, alkalosis, hypocalcemia, tetany
Calcium gluconate Stabilizes membrane irritability
1 mL/kg of 10% solution IV over 3-5 minutes
Bradycardia, hypercalcemia
hypocalcemia• Clinical manifestations1) Increase neuromuscular irritability: muscle
cramps, carpopedal spasm(tetany), weakness, paresthesia, laryngospasm.
2) Seizure like activity3) Chvostek sign4) Trousseau sign
ECG-characteristics of hypocalcemia
• Prolongation of the QT-interval
treatment:-• Severe tetany treated with I.V calcium
gluconate 2ml/kg of 10% solution, given slowly over 10 min while cardiac status is monitored for bradycardia.
• Keep serum calcium in the lower half of the normal range to avoid episodes of hypercalcemia
hypercalcemia• Clinical manifestations• mental disturbances, anorexia, constipation,
lethergy, vomiting, weakness and polyuria
• ECG changes: short QT interval and a widened T wave suggest hypercalcaemia
Treatment:-• Aggressive therapy with normal saline
because the child is usually dehydrated• Loop diuretics enhance Ca excretion,started
after rehydration.• Furosemide (Lasix) (0.5-1mg/kg, Max Dose
10mg/kg/day)• Monitor serum sodium, potassium,
bicarbonate and magnesium.
Metabolic acidosis:-• defined as pH < 7.35, PCO2< 35 mm Hg, and serum bicarbonate <
20 meq/L• the most common acid-base abnormality encountered in
children. Causes of Metabolic Acidosis Normal anion gap• Diarrhea• Renal tubular acidosis• Urinary tract diversions• Increased anion gap• Lactic acidosis• Ketoacidosis (diabetic, starvation, or alcoholic)• Poisoning (e.g., ethylene glycol, methanol, or salicylates)• Inborn errors of metabolism
Anion gap:• Useful to diffrentiate between bicarbonate
loss from net acid gain.• Normal range 10-14 mEq/L.• In acidosis: Undetermind anion above normal range is
considered to be net acid gain. Normal anion gap indicate bicarbonate loss by
gastrointestinal or renal system.• Anion gap=SNa - (SCl + SHC03)
Clinical manifestations:• Tachycardia, ventricular arrhythmia, reduced
cardiac contractility• deep rapid breathing, termed Kussmaul
respirations.• Abdominal pain.• Increased serum uric acid,hyperkalemia.
treatment• Treatment of the underlying disorder
» DKAinsulin» Uremiadialysis» Carbon monoxide poisoningoxygen
• Sodium bicarbonate• 0.5 meq/Kg IV over 10-15 minutes
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