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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