Alterations in Fluid

8/3/2019 Alterations in Fluid

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Alterations in Fluid, Electrolyte and Acid-Base Balance

Pediatric DifferencesECF/ICF ratio varies with age

Neonates and infants have proportionately larger ECF vol

Infants: high daily fluid requirement with little fluid reserve; this makes the infantvulnerable to dehydration.

Distribution of Water

Fluid Loss; Infants and <2yr.excretion is via the urine, feces, lungs and skin

have greater daily fluid loss than older child

more dependent upon adequate intake

greater about of skin surface (BSA), therefore greater insensible loss.

respiratory and metabolic rates are higher

therefore, dehydrate more rapidly

FIGURE 23–2 The newborn and infant have a high percentage of body weightcomprised of water, especially extracellular fluid, which is lost from the body easily.

Note the small stomach size which limits ability to rehydrate quickly.

Mechanism to Restore balancekidney: conserves water, regulates electrolyte excretion

>2yr kidneys immature

less able to conserve or excrete water and solutes effectively

greater risk for acid/base imbalances

Will use the SG norm: 1.005-1.015

Fluid Volume Imbalances

Dehydration: loss of ECF fluid and sodium.

Caused by: vomiting, diarrhea, hemorrhage, burns, NG suction.Manifested by wt loss, poor skin turgor, dry mucous memb., VS changes, sunken

fontanel

Fluid overload: excess ECF fluid and excess interstitial fluid volume with edema.

Causes: fluid overload, CHF.

Manifested by wt.gain, puffy face and extremities, enlarged liver .

Nursing Considerations

How can the nurse determine if the child is mildly dehydrated vs moderately

dehydrated?

Mild Dehydration: by history.

hard to detect because the child may be alert, have moist mucous membranes and

normal skin turgor .Wt loss may be up to 5% of body weight.

The infant might be irritable; the older child might be thirsty

vital signs will probably be normal

Capillary refill will most likely be normal

Urine output may be normal or sl less

Moderate Dehydration

dry mucous membranes; delayed cap refill >2 sec; Wt loss 6-9% of body weight



irritable, lethargic, unable to play, restless

decreased urinary output: <1ml/kg/hr; dark urine with SG > 1.015 (in child >2yr (

Sunken fontanel

HR increased, BP decreased. Postural vital signs

Severe Dehydration

wt loss > 10% body weightlethargic/comatose

rapid weak pulse with BP low or undetectable; RR variable and labored.

dry mucous membranes/parched; sunken fontanel

decr or absent urinary output.

Cap refill >4sec

Types of Dehydration and Sodium Loss

Sodium may be:

Low

High

Or normal

Isotonic Dehydration or Isonatremic Dehydration

Loss of sodium and water are in proportionMost of fluid lost is from extracellular component

Serum sodium is normal (130-150mEq/L) Harriet Lane Handbook, 2000.Most practitioners consider below 135 and above 148 a more conservative

parameter (138-148(

Most common form of dehydration in young children from vomiting and diarrhea.

Hypotonic or Hyponatremic Dehydration

Greater loss of sodium than water Serum sodium below normal

Compensatory shift of fluids from extracellular to intracellular makes

extracellular dehydration worse.Caused by severe and prolonged vomiting and diarrhea, burns, renal disease. Also

by treatment of dehydration with IV fluids without electrolytes.

Hypertonic or Hypernatremic Dehydration

Greater loss of water than sodium

Serum sodium is elevated

Compensatory shift from intracellular to extracellular which masks the severity of

water loss (dehydration) delaying signs and symptoms until condition is quite serious.Caused by concentrated IV fluids or tube feedings.

Rotavirus

Common viral form of diarrhea

All ages but 3 mo-2yrs most common

Fecal/oral route

Virus remains active;

10days on hard, dry surfaces



4hrs on human hands

1wk on wet areas

Rotavirus (cont(.

Incubation period 1-3 days

Symptoms: mild/mod fever, stomach ache, frequent watery stools (20/day(

Treatment: prevention! Hand washing and isolation of the infected child.

Fluid rehydration for diarrhea, advanced to bland diet for older children

Breast milk for the infant who BF

Clinical Management for Dehydration

Blood may be drawn to assess electrolytes, BUN and Creatinine levels

an IV may be placed the same time

Oral Rehydration Solution is the treatment of choice for mild-moderatedehydration

1-3tsp of ORS every 10-15min to start (even if vomits some(

50ml/Kg/Hr is the goal for rehydration.Why are drinks high in glucose avoided during rehydration?

Answer to why high glucose drinks are avoided:

Recommended foods during rehydration progression:

starches, cooked fruits & vegetables, soups, yogurt, formula, breast milk .

BRAT diet used to be recommended, but recent research has shown no differencethan return to normal diet with some attention to lactose containing foods, depending

upon the child’s response.

IV Therapy

Used for severe dehydration or in the child who will not/cannot tolerate ORS

Half 24hr maintenance plus replacement given within first 6-8hr (in ER) to

rapidly expand the intravascular space. Usually a normal saline bolus.slower IV rate for the remainder of the first 24hrs

nurse records IV vol infused hourly

Rehydration and IV solution

Why is the child initially rehydrated with a normal saline bolus and not an IV

solution with potassium?

Answer to rehydration and IV solution question:

Which of the following IV solutions replaces Sodium?

D5 W

Lactated Ringers Normal Saline

D5 ½ NS

Answer :

All but D5 W

See IV solutions table B & B p. 733



Calculation of intravenous fluid needs: maintenance

see pg 735 B&B, Box 23-5.

For the 1st 10 Kg, replace at 100ml/Kg

for the second 10 Kg, replace at 50ml/Kg

for >20kg, replace at 20ml/Kg

Example of Maintenance Fluid CalculationYour patient is a 10 yr old weighing 35 Kg. You want to determine this patient’s

24hr maintenance fluid needs:

for the first 10 Kg give 100ml/Kg = 1000ml

for the second 10 Kg: 50ml/Kg = 500ml

for the remaining 15 Kg (35-20Kg) , replace at 20 ml/Kg = 20 (15) = 300ml

1000+500+300=1800ml/day.

How much fluid should this patient get per hour?

1800ml / 24 hrs = 75 ml/hr .

Therefore, if the patient were NPO and not taking in fluids from any other source,

the IV should be running at 75ml/hr .

If there is a deficit that also needs to be replaced, the IV rate may be slightlyhigher for a defined period of time.

If the patient is receiving fluids from other sources, these need to be accounted as

well

Practice Problems for Calculating 24hr Fluid Maintenance and the hourly IV rate for :

A 9 yr old patient who weighs 20 Kg.

A 6 mo old baby who weighs 8 Kg

An 24mo old toddler who weighs 18 Kg

A 3 yr old preschooler who weighs 28 Kg

An 18 yr old who weighs 50 KgAnswers for 24hr Fluid Calc.

Fluid Overload:EdemaIncr capillary blood flow: inflammation, infection

venous congestion: ECF excess, R sided heart failure, muscle paralysis.

Incr albumin excess: Nephrotic Syndrome

Decr albumin synthesis: Kwashiorkor, liver cirrhosis

incr capillary permeability: inflam/ burns

blocked lymphatic drainage: tumors/surg.

Clinical Assessment/Management of Edemaassess dependent limbs if ambu or sacrum is lying

ascites; periorbital edema; rings too tight pitting edema for degree of swelling

daily wt and strick I and O

elevation/change position Q2hr/ protect skin against breakdown

distraction to deal with discomfort and limitations of edema.

Electrolyte Imbalances



Electrolytes usually gained and lost in relatively equal amounts to maintain

balance

Imbalance caused by:

Abnormal route of loss (vomiting/diarrhea) can disturb electrolyte balance

Disproportionate IV supplementation

Disease states: renal dis.Hypernatremia

Excess serum sodium in relation to water

Causes:

Too concentrated infant formula

Not enough water intake

Clinical manif : thirst, lethary, confusion

Seizures occur when rapid or is severe.

SG concentrated 1.020-1.030

Lab test: serum sodium

Treatment: hypotonic IV solution

HyponatremiaExcess water in relation to serum sodium

Most common sodium imbalance in children

Causes:

Infants vulnerable to water intoxication:dilute form, excess pool water, poorly

developed thirst mech so cont to drink and can’t excrete excess water .

Clinical manif : decreased level of consciousness d/t swelling of brain cells.

Anorexia, headache, muscle weakness, decreased DTR’s, lethargy, confusion or

coma.Seizures occur when rapid or severe.

SG dilute: 1.000-1.0005

Lab tests: serum sodiumTreatment: hypertonic solution.

HyperkalemiaExcess serum potassium

Causes:

excess K intake from IV overload, blood transfusion, rapid cell death (hemolytic

crisis, large tumor destruction from chemo rx, massive trauma, metabolic acidosis from

prolonged diarrhea and in DM when insulin levels are lowInsulin drives K back into the cells

decreased K loss from Renal insufficiency

Clinical manif : all are related to muscle dysfunction: hyperactivitiy of GI smoothmuscle: intestinal cramping and diarrhea.

Weak skeletal musclesLethargy



Cardiac arrhythmias (tachycardia, prolonged QRS, peaked T waves: also AV

block and VTach.(Lab test: serum potassium

Treatment: correct underlying condition (take K out of the IV(dialysis (peritoneal or hemo), Kayexalate (po or enema), K wasting diuretics, IV

calcium, bicarbonate, insulin and glucose.Low potassium diet.

HypokalemiaDecreased serum potassium

Causes: diarrhea and vomiting, ingestion of large amts black licorice, diuretics,osmotic diuresis (glucose in urine as in DM), NPO without K replacement in IV, NG Sx,

bulimia, insulin.

Also in nephrotic syndrome, cirrhosis, Cushing Syndrome, CHF (to be coveredelsewhere(

Clinical manif : muscle dysfunctionSlowed GI smooth muscle resulting in abdominal distention, constipation and

paralytic ileusSkeletal muscles are weak; may effect respiratory muscles

Cardiac arrhythmias: hypokalemia potentiates Digitoxin Toxicity.Lab test: serum potassium

Treatment: oral and/or IV potassium, diet rich in K .

HypercalcemiaExcess calcium

Needs vit D for efficient absorption; most of Ca is stored in the bones.

Causes: bone tumors that cause bone destruction, chemo rx release Ca from the bones; immobilization causes loss from the bones (usually excreted) but if kidneys can’t

clear it, hypercalcemia results, increased intake (milk-alkali syndrome.(

Clinical manif : Ca imbalances alter neuromuscular irritability with non-specific

symptoms

Constipation, anorexia, N/V, fatigue, skeletal muscle weakness, confusion,lethargy.

Renal calculi, cardiac arrhythmias

HyperCa increases Na and K excretion leading to polyuria and polydipsia.Rx: serum Ca, Ionized Ca, fluids, Lasix, steroids, dialysis.

HypocalcemiaDecreased serum calcium

Causes: decreased intake of Ca and/or Vit D (adolescents are vulnerable d/t fad

diets and the deficit cannot be made up later, increasing risk for osteoporosis.(

Limited exposure to sunlight, premature infants and dark skinned people at

increased risk to inadeq. Vit D and therefore decreased Ca absorption.Parathyroid dysfunction, multiple transfusion (Citrate binds Calcium), steatorrhea

(as in pancreatitis and Cystic Fibrosis) binds Calcium in the stool.



Clinical Manif :acute situation related to increased muscular excitability: tetany.

+Chvostek’s Sx, + Trousseau’s Sx.In children: Twitching, cramping, tingling around the mouth or fingers,

carpal/pedal spasms.

In infants: tremors, muscle twitches, brief tonic-clonic seizures, CHF.Laryngospasm, seizures and cardiac arrhythmias in severe situations.

In children and adolescents, chronic hypocalcemia more common, manif. By

spontaneous fractures.

Lab tests: serum Ca; bone density study

Rx: oral and/or IV Ca, Ca rich diet

Hypermagnesemia

Excess in Mg.

Imbalances characterized by neuromuscular irritability

Causes: impaired renal function, Mag Sulfate given perinatally to treat eclampsia,increased use of laxatives, enemas, antacids, IV fluid additives.

Clinical Manif : decreased muscle irritability, hypotension, bradycardia,drowsiness, lethargy, weak or absent DTR’s.

Rx: increase fluids, diuretics, dialysis.

HypomagnesemiaDecreased serum Mg.

Stored in cells and bones

Causes: prolonged NPO without replacement, chronic malnutrition, chronic

diarrhea, short bowel syndrome, malabsorption syndromes, steatorrhea, multipletransfusions, prolonged NG Sx, some medications.

Clinical manif : increased neuromuscular excitability (tetany). Hyperactive

reflexes, skeletal muscle cramps, twitching, tremors, cardiac arrhythmias, seizures.

Lab: serum Mg along with Ca and K .

Rx: po/IV Magnesium admin and treating underlying cause of imbalance.

Critical Thinking: Clinical Evaluation of Fluid and Electrolyte Imbalance

B & B p. 757

How can you evaluate children appropriately for fluid and electrolyte imbalance

without thinking through the clinical manifestations of every possible disorder, one after the other ?

Answer to Critical Thinking:

Fluid and Electrolyte Worksheet

Use the fluid and electrolyte worksheet to help review some of the major conceptsof fluid and electrolyte imbalance.

Acid Base Balance

normal arterial blood pH: 7.35-7.43 (in general(



Acidosis < 7.35 : too much acid

Alkalotic > 7.43 : too little acid

pCO2 reflects carbonic acid status: 40 +- 5

HCO3- reflects metabolic acid status:

24-+4

Respiratory Acidosiscaused by decr respir effort

build up of CO2 in the blood

pH decr or normal; pCO2 incr .

Symptoms manifested: confusion, lethargy, HA, incr ICP, coma, tachycardia,

arrhythmias

Management of Respiratory Acidosis

Incr ventilatory rate

give O2

intubate

adm NaHCO3

Clinical Conditions that cause Respir Acidosisconditions associated with decreased respiratory drive, impaired gas exchange/air

trapping, ie:

head trauma, general anesthesia, drug overdose, brain tumor, sleep apnea,mechanical under ventilation, asthma, croup/epiglottitis, CF, atelectasis, MD,

pneumothorax.

Respiratory Alkalosis

caused by hyperventilation

CO2 is being blown off

pH incr : pCo2 decr

Symptoms: dizziness, confusion, neuromuscular irritability, paresthesias inextremities and circumoral, muscle cramping, carpal or pedal spasms.

Management of Resp. Alkalosis

First determine if oxygenation is adequate, if not, you don’t want to slow the RR .

Determine the cause and correct it:

Causes of hypervent: hypoxemia, anxiety, pain, fever, ASA toxicity,

meningitis/encephalitis, Gram - sepsis, mechanical overventilation.

Ipecac is no longer recommended for treatment of ingestions.

Metabolic Acidosis

caused by a loss of bicarbonate (HCO3(

therefore, is an incr of acids in the blood

pH decr or moving towards normal

pCo2 decr ; HCO3 decr

Symptoms: Kussmaul respirations = incr rate and depth as compensation

(hyperventilation/acetone breath), confusion, hypotension, tissue hypoxia, cardiac

arrhythmias, pulmonary edema.

Management of Metabolic Acidosis

Identify and treat underlying cause

In severe case may give IV NaHCO3 to incr pH, or insulin/glucose.



Causes of MA for gain of acid: ingestion of ASA, antifreeze, oliguria, RF, HAL,

DKA, starvation or ETOH KA, lactic acidosis (tissue hypoxia.(

Loss of HCO3: maple syrup urine disease, diarrhea, RF.

Metabolic Alkalosis

caused by loss of H+ or HCO3 retention

HCO3 incr with probable incr in pH, incr pCO2.Symptoms:weak, dizzy, muscle cramps, twitching, tremors, slow shallow resp.,

disorientation, seizures.

Management of Metabolic Alkalosis

correct underlying cause; facilitate renal excretion of HCO3.

admin NS, K+ if hypokalemic, replace loss of fluids, prec for Sz, monitor I and O

and electrolytes

Causes: prolonged vomiting, ingestion of lg quantities of bicarb, antacids, loss of

NG fluids, hypokalemia from prolonged diuretic use, multiple blood transfusion withcitrate.

ABG Basic (Uncompensated) Analysis

Resp Acidosis: low pH and high PaCO2Resp Alkalosis: incr pH and low PaCO2

Metab Acidosis: low pH and nl PaCo2; decr HCO3

Metab Alkalosis: high pH; nl PaCO2 ; high HCO3

ABG Analysis with Compensation

Resp Acidosis: HCO3 will incr, pH will approach nl; PaCO2 will still be

increased

Resp Alkalosis: HCO3 will decr, pH will approach nl; PaCO2 will still be

decreased

Metab Acidosis: PaCO2 will decr, pH will approach nl; HCO3 will still be

decreased

Metab Alkalosis: PaCO2 will incr, pH will approach nl; HCO3 will still beincreased

Examples of ABG:

pH 7.35-7.43 PaCO2 35-45 HCO3 20-28 = Norms

pH 7.33 PaCO2 52 HCO3 26

pH 7.48 PaCO2 32 HCO3 24

pH 7.28 PaCO2 37 HCO3 18

pH 7. 45 PaCO2 38 HCO3 32

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Alterations in Fluid