2. fluid, electrolyte, and acid-base balance (reduced)

8/7/2019 2. Fluid, Electrolyte, And Acid-Base Balance (Reduced)

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DAILY MAINTENANCE FLUID REQUIREMENTS

Body Weight (kg) Amount of fluid per day (Basal Maintenance)

1 10 100 ml/ kg

11 20 1000ml + 50 ml/ kg for each kg>10 kg20 1500 ml + 20 ml/ kg for each kg > 20 kg

Normometabolic state, at rest;

Estimated fluid requirements-----increased or decreased fromthese parameters -----increased/decreased of H2O losses,

e.x Elevated body temperature

CHF


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Distribution of body fluids

Water is the major constitutes of body tissues

TBW range (of total body weight) from

40% - 60% adults75% infants

Loss of 20% - fatal

Distribution of body fluids, or total body water (TBW),involves the presence of

Intracellular(ICF)

Extracellular(ECF) fluids


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So where are these fluids kept?

Body fluids are divided between the intracellular& extracellulardepartment

Most of our body fluid (2/3) is found in the intracellular

department.

ICFContains solutes such as Oxygen, electrolytes protein & glucose.

ICF provides a medium in which metabolic processes of the celltake place.

ICF contain electrolytes as K, Mg (primary electrolytes)


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Extracellular(ECF)

Fluid outside the cells

It is the transport system that carries nutrients &

waste products to and from the cells

Newborn 50% of body fluid contained within

ECF

Toddler 30% of body fluid contained within ECF


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Abundance

Lubricant

Medium todissolve body

solutes

(Na+, O2)

Insulator

Place formetabolicreaction

Shockabsorber

Transport ofnutrients, waste &other substancesBTW Blood & cell

Regulating &

maintainingbody Temp


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ICF & ECF contain

Oxygen & CO2 Dissolvednutrients

+ve charge ion(Cation)

_ve (anion)

Excretoryproducts

Ex NaCl breaksinto Na+ Ion &

Cl- Ion

(electrolytes)

Ions(dissolved

salts)

K+ major cationICF & it

maintain ICFbalance

Na+ majorcation ECF

It control water

balance


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Composition of body fluids

Electrolytes are measured in milliequivalentsper liter of water( mEq/L).

Other body fluids such as gastric andintestinal secretions also containelectrolytes


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Mechanisms of fluid movements

Water is retained in the body in a relatively constantamount and it is almost freely exchangeable among allbody fluid compartments (ICF & ECF)

Transport mechanisms are the basis for all activitywithin the cells, and since they have limited ability tostore materials, movement in and out of cells must berapid.

Internal control mechanisms (such as thirst,antidiuretic hormone (ADH), and aldosterone (whichenhances sodium reabsorption) are responsible fordistribution & maintenance of fluid balance.


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The principles involved in this shifting are

Diffusion

Filtration

Osmosis

Active transport

Regulation of Fluids in Compartments


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Hydrostatic pressure/Filtration

movement of fluid&solutes

one of lower pressure

an area of higher

hydrostatic pressure

The pressure

created by theweight of fluids

Its caused frompressure oncapillaries Moves water &

solutes intointerstitial spaces

from

to


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Osmotic pressure

water movement across

the cell membranes

from low soluteconcentration (low osmoticpressure)

No energy required

higher concentration of

solute(high osmotic pressure)


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Movement of water in the body between cells

(extracellular fluid) is caused by osmosis.

This is created by magnetic forces in the body,which keep the movement in balance. As waterflows, changes in pressure create movementacross the cell membranes.

Any changes in pressure will allow proteins,minerals and other nutrients being carried by

the blood to escape into spaces betweenvessels and deprive the cells of their vital

needs to sustain life.


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Active Transport

movement of substanceacross the cell membrane

from

Higher concentrationBy

Less concentrationsolution

To

Active transport

( a carrier)

Burn calories

Spend a bit energy


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Osmosis versus Diffusion

Osmosis Diffusion

Low to high High to low

Water

potential

Movement

of particles

Both canoccur at

the same

time

Both canoccur at

the same

time


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Osmolality

Osmolality is

The concentration of solutes in the body

fluids,

Reported as milliosmols per kilogram

(mOsm/kg).

Sodium is the greatest determinant of serum

osmolality.


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Tonicity

It refers to the osmolality of solution:

Tonicity is a measure of the osmotic pressure of two solutionsseparated by a semi-permeable membrane.

has the same osmolality as body fluids ( eg NormalIsotonic solution

saline 0.9%)

has a higher osmolality than body fluids ( egHypertonic solutionNormal saline 3%)

has a lower osmolality than body fluids ( egHypotonic solutionNormal saline 0.45%)


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IMBALANCES

It occurs when body fluids are lost in excess of fluidgain

The great majority of disturbances in hydration & electrolytesbalance occur secondary to vomiting & diarrhea

Fluid Imbalances-1Causes of dehydration are:

1. Lack of oral intake.

2. GI ; vomiting, diarrhea, malabsorption

3. Burns

4. Fever

5. Diabetes mellitus

6. Tachypnea as in bronchiolitis


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Types of dehydration


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Isotonic /Isonatremicdehydration:

Hypertonicdehydration/hypernatremia

Hypotonic/Hyponatremiadehydration

Occurrence

fluids & electrolytes losses are in

same proportion as they exist inthe body

water intake decreases

&Na increases

decrease in Na &

retention of water

10-20% of children with

dehydration havehypertonic/hypernatrmic

Fluid osmolarity is not affected &

there is deficit of TBW.

Proportionally greater

loss of water than Na

It can be caused by

excessive plain

water intake and

defect in renal water

excretion and failurein Syndrome of

inappropriate

antidiuretic hormone

(SIADH)

Hypotonic/ Hyponatremia

dehydration

is occur in 10% of children

with dehydration.

70% of children with diarrhea occur when insensible

loss of water from skin &

respiration tract is high

CF is due to

excessive lose of

Na via sweat.

(plasma Na+ remains normal

130-150 mEq/L).

In this case the Na

increase the osmotic

pressure in the blood

vessels that shifts the

fluids from the IC to the

ECS(plasma Na+ > 150

mEq/L) .

The water shifts

from ECS to ICS

causing circulatory

collapse.


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Disturbances in Fluid Volume, Electrolyte&

Acid-Base Balances

Many factors affect the fluid & electrolyte balance such asillness, surgery, medications, burns, vomiting,diarrhea and nasogastric suction.

The majority of childhood illnesses that caused imbalances

they occur secondary to vomiting and diarrhea.

The imbalances can be:

1. Total body deficit/excess of fluid and electrolyte with theosmolality of the body is not affected.

2. When relationship between fluid & electrolyte has beenaltered & the osmolality is altered (electrolytes+++with dehydration & dec- with overhydration).

3. both a and b.


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Factors Affecting Body Fluid, Electrolytes and Acid-

Base Balance

infant has immature kidneys, rapid respiration and:age-1more body surface area than adult which make the infantloses the fluid rapidly.

In elderly people, the thirst response often is blunted and

kidney become less able to conserve water that will affectthe fluid balance.

Female having more fat (people:Gender and Body Size-2with a higher percentage of body fat have less fluid).

both salt and water are lost:Environmental Temperature-3through sweating in hot climate

diet, exercise, stress and alcohol consumption all:Lifestyle-4affect the fluid and electrolyte balance


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Sodium ImbalanceSodium ImbalanceHypertonic DehydrationHypertonic Dehydration

Gain of Na+ in excess of waterPlasma Na+ > 145 mEq / L

The causes of hypertonic/hypernatrmic can be

1. Administration of hypertonic IV fluids

2. Increase of Na intake

3. Failure of ADH (H2O loss Increase in ECF)

4. Increase of insensible loss of water as

in burn, fever, respiratory infections.

5. RF

The defense mechanisms for this case are

stimulation of thirst

stimulation of ADH.


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Hypotonic DehydrationHypotonic Dehydration

Overall decrease in Na+ in ECF (Plasma Na+ < 130 mEq/L)

Causes

1. Excessive plain water intake & defect in renal water

excretion

2. C.F (excessive loss of Na+ via sweating)

Which leads to:

H2O shifting from ECF into ICU causing circulation collapse

Clinical manifestations

Neurological symptoms

Lethargy, confusion, apprehension, depressed reflexes, seizures and

coma


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Overdehydration/ Edema

Over dehydration is the excess ofinterstitial fluid caused by:

Receiving IVF very fast (Kidney Function is normal)

Patient receiving dialysis or enema

Edema is the presence of excess fluid in the interstitial spaces.

. Fluid Volume excess FVE :1

FVE increase the capillary pressures, pushing fluid into the interstitial tissuesby filtration. (e.g heart failure and renal failure).

. Low levels of plasma proteins in blood:2

This will reduce the oncotic pressure so that fluid is not drawn into the capillariesfrom interstitial tissues. (e.g nephritic syndrome and malnutrition).

OP is exerted by proteins in blood plasma that usually tends to pull waterinto the circulatory system


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. Allergic reaction:3

The albumin can move easily from the capillaries membrane pulling

with it the fluid. This can be seen also in burns & truma.capillaries become more permeable allowing the fluid to escape intointerstitial tissues.

. Increase in interstitial oncotic pressure:4The protein enter the interstitial fluid (tissue fluid) more than theyleave causing increase in interstitial oncotic pressure that in turnpull the fluid into tissue as in tumors and hypothyroidism

. Obstructed lymph flow :5This impairs the movement of fluid from interstitial tissues back intothe vascular compartment.


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Edema

Taking accurate daily weights is important to detect any weight

changes.

Vital signs, physical appearance, and changes in urine character or

output are noted.

Edema (general) in infants may first be seen around the eyes and in

the presacral, occipital, abdominal girth or genital areas.

Pitting edema,

Exerting gentle pressure with the finger 5 sec having an impression in

the skin that lasts for several seconds


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Electrolyte Imbalance/ PotassiumPotassium

PotassiumPotassium (95% of K of body in ICF)mEq/L5.3K serum


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PotassiumPotassium

0.5K >b.) Hyperkalemia:

Most commonly occur in children as a result of too rapidadministration ofIV potassium chloride,

Significant dysrhythmias and cardiac arrest may result when potassium levels ariseabove 6.0 mEq/L

Caused also by

Renal failure,Shift ofK from IC to EC by tissue damage

Metabolic acidosis

S&S: malaise, muscle weakness, oliguria to anuria, abnormalcardiac function and D & Nausea


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HypocalcaemiaCalcium (required for activation of numerous enzymes, cardiac, neural &muscular functions

mEq/L,0.4Ca Hypercalcemia:b.)

caused by increase administration of Vit A and D, prolonged immobilizationand hyperparathyroidism.

S&S:

nausea, vomiting, constipation and flank pain


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Acid-Base balanceHomeostasis: a balance of fluids, electrolytes and acids and bases in the body; thatreflects a good health.

excretion of carbonpulmonary and renalbase balance is maintained by normal-Aciddioxide and acid, respectively.

Acid-base balance is a dynamic relationship which reflects the concentration of

hydrogen ions (H+) in the body

hydrogen ions (ex Carbonic acid)releasesis the substanceAcidA drop in pH is called acidosis

)3hydrogen ions (HCOacceptcanBase

A rises in pH is called alkalosis

PH is the relative acidity or alkalinity of a solution:

# higher hydrogen ions lead to more acidity which is low pH 7.


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Body fluid PH

Body fluids are slightly alkaline

45.7-35.7Normal pH of arterial blood is-

several body systems including

1. Buffers,

2. Respiratory system,

3. Renal systemAre maintaining the narrow pH


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Regulating Acid-Base balance

Buffers (Fastest)-1

(solutions that tend to resist changes in their PH as acid/base added)

Major buffers system in ECF is the carbonic acid ( H2CO3) & its conjugatedbase; bicarbonate (HCO3)

plasma proteins, hemoglobin andBesides bicarbonate & carbonic acid buffers,phosphates also function as buffers in body fluids.

HCO3 + H+ H2CO3 this is a weak volatile acid eliminatedCO2 + H2O H2CO3 HCO3 + H+

Respiratory Regulation:-2Regulating acid-base balance by eliminating or retaining carbon dioxide (CO2)by altering the rate and depth of respirations.


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-If the blood level ofcarbonic acid (H2CO3) increase the rateand depth of respirations increase (hyperventilation) toexcrete CO2 to fall the level of H2CO3

If the blood level of bicarbonate (HCO3-) increase the rate anddepth of respirations decrease (hypoventilation) to retain theCO2 and rise the level of carbonic acid.

- PCO2 refer to pressure of carbon dioxide in venous blood

-PaCO2 refer to pressure of carbon dioxide in arterial blood.

Normal PaCO2 is 35-40 mmHg


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3- Renal Regulation:

Normal serum bicarbonate level is 22-26 mEq/L

- kidneys maintain acid-base balance by excreting or

conserving bicarbonate (acid) & hydrogen ions

- Ifacidity increased the kidneys reabsorb and regeneratebicarbonate and excrete H

- In the case ofalkalosis excess bicarbonate is excretedand H ion is retained


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Acid-Base imbalances

The abnormalities in PaCO2 increase/decrease is calledrespiratory alkalosis/acidosis because PCO2 regulated byrespiration

# Increase in PaCO2 ---------------- respiratory acidosis

# Decrease in PaCO2----------------respiratory alkalosis.

The abnormalities ofplasma bicarbonate concentration refer tometabolic process

# Increase in HCO3---------------------metabolic alkalosis

# Decrease in HCO3------------------- metabolic acidosis


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Respiratory Acidosis:

Hypoventilation and CO2 retention cause carbonic acid level to increase which willdrop the pH level below 7.35.

Ex. pH 7.28 (acidic) PaCO2 74 HCO3 26 N

When respiratory acidosis occurthe kidneys will retain bicarbonate to restore thenormal ratio of bicarbonate:carbonic acid (20:1) in order to restore the normalpH

pH 7.33 PaCO2 74 HCO3 32 (Compensated Res Acid)

This can be caused by

1. asthma

2. central nervous system depression

3. anesthesia, alcohol ,

4. aspiration of foreign body.

5. Pneumonia

S&S

1. Headache 2. Blurred vision

3. Restlessness 4. Anxiety 5. Tremors


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Respiratory alkalosis:

Hyperventilation makes the CO2 to be exhaled causing the carbonic acid to fall and risethe pH above 7.45.

Ex. pH 7.50 (alklosic) PaCO2 30 HCO3 23 N


1. Tetany

2. fever,

3. anxiety,

4. respiratory infection.

With respiratory alkalosis the kidneys will excrete bicarbonate to return normal pH.

pH 7.46 PaCO2 30 HCO3 20 (Compensated Res Alklosis)

S&S1. increase irritability of central and peripheral nervous system.

2. Light headache

3. Altered consciousness

4. Paresthesia of extremities

5. arrhythmias


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Metabolic Acidosis (diarrhea)When bicarbonate is low in relation to the carbonic acid in the body, causingthe pH to fall.

Ex. pH 7.21 PaCO2 40 (N) HCO3 15.6


1. Renal failure

2. Inability of the kidneys to excrete H ions.

3. Increase of anaerobic metabolism

4. Decrease in blood volume causing the kidney to function less effectively

Metabolic acidosis will stimulate the respiratory centercausing the rate anddepth of respiration to increase in which the CO2 is eliminated andthe carbonic acid is fall).

pH=7.34 PaCO2=28 HCO3= 15.6S&S

1. Increase depth of respiration 2. Arrhythmia

3. Lethargy----coma 4. Impaired growth (rickets)

5. Wt loss 6. Anorexia

7. Muscle weakness and listlessness.

Metabolic alkalosis (vomiting):


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Metabolic alkalosis (vomiting):

When the amount of bicarbonate in the body exceeds the normal 20:1 ratio.This can be caused with ingestion of antacid, vomiting which causinglosing in H.

pH= 7.51 (Inc) PCO2=40 HCO3= 30.4 (hig)

The metabolic alkalosis will stimulate the respiratory center to slow and shallowthe breathing (causing to retain CO2 which will increase the carbonicacid level) pH=7.46 PaCO2= 45 HCO3= 31.2

Causes are

1. Muscles hypertonic

2. vomiting

3. nasogastric suctioning

4. diuretics;5. Hypokalemia .

6. HCO3 retention may result from, massive blood transfusion, excessiveadministration of sodium bicarbonate

S&S

1. Weakness 2. Muscle cramp 3. Dizziness


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Nursing Assessment

1. Nursing History

Ask about: vomiting, diarrhea, food given during illness, urination,recent changing in behaviors and activities, wt, fever, evidenceof infection, and medication.

2- Physical Assessment

- skin: color , temperature, moisture, edema, turgor- mucous membrane: color , moisture

- eyes: firmness

- Fontanels (infants): firmness level

- cardiovascular system: heart rate, peripheral pulses, bloodpressure, capillary refill, venous filling

- respiratory system: respiratory rate & pattern, lung sounds

- neurologic: level of consciousness (LOC), orientation, motorfunction, reflexes.


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. Vital signs:1

Early phase of ECF volume depletion is increase in Temp.

Pulse is rapid weak and thready in dehydration (thready pulse is anabnormal pulse that is weak and often fairly rapid, the artery does not feel fulland the rate may be difficult to count).

but the bounding pulse occurs in increase of plasma fluid volume

(decrease hematocrit & HG ) and in hypertonic dehydration.

In metabolic acidosis the compensatory mechanism will increase therespiratory rate.

And in potassium alteration whether its increase or decrease thebreathing will be shallow.

BP will increase in fluid volume excess.


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Vital Sign

Temp Pulse R.R B/P

Increase Early

phase of ECF

depletion

Dehydration:

Thready,

Rapid, Weak

Increase

Metabolic

acidosis

Increase

FVE

Bounding

Increase

plasma fluid

volume

Incr/decr

Potassium

alteration

Bounding

Hypertonic

dehydration


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Weight for infant and young

children

Mild dehydration Moderate dehydration Severe dehydration

3-5% loss of body W.T 6-10% loss of body W.T 10% loss or more

Fluid volume loss ofmore than 50 ml/kg

Fluid volume loss of 50-100ml/kg

Fluid volume loss of100ml/kg or more


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W.T for older children

Mild isometricdehydration

Moderate dehydrationSevere dehydration

if3% of body weigh islost

if6% of body weight islost

if9% of body weight islost


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Anterior fontanel & eyes

FVE Dehydration Sever dehydration

Fontanel

Tense &

bulging

Depressed &

sunken

Eyes are

sunken

Suture skullbecomes

prominent


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.. Intake and Output and Urine specific gravity4

In fluid excess the USG is decreased (normal value 1.010-

1.025).

Urine intake should approximate the output:

hrs24Urine output/Neonate 50-300 mL

Infant 350-550 mL

Child 500-1000 mL

Adolescent 700-1400 mLAdult 1500-2000 mL.


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. Neurologic Status:5

In dehydration the child may become irritable to lethargic andcry with high pitched or weak.

In hypo/hyperkalemia: there is muscle weakness, tetany.

In Hyponatremia: confusion, headache, delirium and convulsion.

In hypernatremia: intracerebral bleeding, brain damage.

. Laboratory Assessment:6

A.) Arterial Blood Gases for acid-base imbalance

B.) Urine specific gravity for dehydration

C.) Serum and urine electrolytes

D.) ECG for electrolytes imbalance.


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Nursing Diagnosis

Fluid volume deficit ( Diagnostic label) R.T

excessive fluid loss associated with illness/secondary to,

hemorrhage; diarrhea; vomiting; burns; fever, and

hyperventilation (etiology)

as evidenced by/as manifested by 10 times/a day watery

stool; more than 8 times vomiting, vomit the whole

feeding, sunken eyes and depressed fontanel, dry

skinetc (defining characteristic/signs and symptoms).


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Nursing management

* Maintenance requirements of the fluid and electrolytes that are

necessary to maintain homeostasis for 24 hours,

* The therapy must account for insensible loss, urine output, and

caloric needs.

* The maintenance calculated based on:

Body weight, surface area or caloric expenditure and mostly used

based on caloric expenditure.

*Holliday-Segars formula (method of estimating daily caloric needs)

(Beginning at 100 kcal/kg for an infant)


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Example

Fluid maintenance for a body weight of 24 Kg is:

The first 10 Kg needs 100cc/Kg so = 10*100=1000

The second 10 kg needs 50cc/kg=10*50=500

And more than 20kg needs 20cc/kg=20*4=80

So in total fluid maintenance is =

1000+500+80= 1580cc/day, 1580calorie/day


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Treatment phases

(I) Deficit therapya.) Initial therapy phase: to restores the circulation

with severe dehydration. Ringers lactated, salinesolution, plasma or albumin can be given.

11.) Repletion therapy: correct previous loss andprovide therapy for normal and abnormal ongoing

losses. In this phaseK

cL can be added.

(111) Stabilization phase: maintenance and ongoinglosses; oral intake may be resumed started with

clear fluid.


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Potassium chloride (KcL) administrationGive no more than 40 mEq/L

Never give potassium by IV push

Do not administerKCL if urine output is not age

appropriate


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Total parenteral nutrition

1. TPN consist of carbohydrate, protein, electrolytes, vitamins,

minerals and fat.

2. Indicators for TPN are:

a. malnourished / long period without enternal feeding.

b. Premature infant will need TPN sooner than older child.

c. Major GI tract abnormalities

d. Immune deficiency

e. Inflammatory bowel diseases

f. Severe burns

g. Renal failure

h. AIDs.


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3. The dextrose, amino acids, electrolytes, vitamins and elements are

mixed together with a separate fat emulsion (looks like milk)

administered separately in dropper without filter.

4. TPN can be administered via IV or catheter.

Catheter can be inserted forneonate and infant through external orinternal jugular vein to the superior vena cava.

ForOlder Children:

The catheter can be inserted for older children through the subclavianvein to superior vena cava.


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Care of infants with TPN

The line may become dislodged or clots may form.

A serious infection called sepsis is a possible

complication of a central line IV.

Infants who receive TPN should be closely

monitored by the health care team, sincecomplications can be serious and are not unusual.

Prolonged use of TPN may lead to liver problems.


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2. fluid, electrolyte, and acid-base balance (reduced)

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