Upload
anasokour
View
422
Download
0
Embed Size (px)
Citation preview
Fluid and electrolytes – Developed by Khulood Shattnawi 1
Pediatric Nursing (Nur. 352)
Fluid, Electrolyte, and Acid-Base Balance
Distribution of body fluids:
The distribution of body fluids, or total body water (TBW), involves the presence of intracellular
(ICF) and extracellular (ECF) fluids. Water is the major constitutes of body tissues, and the TBW in an
individual range from 40% to 60% (or 45% to 75% in some other texts) of total body weight.
The ICF refers to the fluid contained within the cells and constitues about 2/3 of the total body fluids
in adults. ICF contains solutes such as Oxygen, electrolytes and glucose. ICF provides a medium in which
metabolic processes of the cell take place. It contain electrolytes as K, Mg, HPO, SO as primary
electrolytes(principal electrolytes).
ECF is the fluid outside the cells and account for 1/3 of the total body fluids. ECF is the transport
system that carries nutrients to and waste products from the cells. It contains electrolytes such as sodium,
chloride, bicarbonate that represents the principal electrolytes in this compartment.
The ECF is further broken down into several components: intravascular (contained within the blood
vessels). It contains electrolytes and a protein-rich fluid (plasma) and large amount of albumin. Interstitial
(surrounding the cell and the location of most ECF, 3/4 of ECF), it contains little or no protein. And
transcellular (contained within specialized body cavities such as cerebrospinal, synovial, pleural, and so on).
In the newborn about 50% of the body fluid is contained within the ECF, whereas 30% of the toddler's body
fluid is contained within the ECF.
The importance of body water to body function is related not only to its abundance but also to the fact
that it is the medium in which body solutes are dissolved and all metabolic reactions take place. In addition, it
is a transporter of nutrients, waste products and other substance, a lubricant, an insulator and shock absorber,
and one's mean of regulating and maintaining body temperature.
Fluid fluctuations affect blood volume and intracellular hydration
levels. This can be life threatening. When the amount of fluid within
various cellular compartments is relatively constant, there is an
exchange of solutes and water between compartments to maintain
unique compositions. Individuals with more body fat have
proportionately less total body water and are more susceptible to
fluid imbalances that cause dehydration.
Total body water percentage decreases with age, resulting in
inadequate cellular hydration. Most critical is the decrease in the
ratio of intracellular hydration. The normal ratio is 60% intracellular,
40% extracellular. The reason for change in this ratio is due in part to an increase in fat along with a decrease
in muscle, and a decreased ability of the body to regulate sodium and water balance. With age, kidney
function becomes less efficient in producing urine, and responses for conserving sodium weaken.
The body must continuously be in a proper state of hydration. Because 2.5 liters of water is lost each day
through normal bodily functions, this must be replaced. There are two major issues that emphasize the need
to keep the body adequately hydrated with water of the best quality, content, and structure so it can maintain
homeostasis. First, the water we put in our body must be able to prevent toxins and chemical substances from
accumulating and creating destructive influences on cells. Water must bring all minerals and nutrients
required for cell metabolism, and remove any substances that can damage the cell. It must also be able to
protect cell walls from damage and invasion. Second, since water is involved in every function of the body, it
Fluid and electrolytes – Developed by Khulood Shattnawi 2
must act as a conductor of electrochemical activity, such as neurotransmission, by moving water from one
nerve cell to another smoothly and effectively.
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 water flows, changes in pressure create
movement across the cell membranes. Any changes in pressure will allow proteins, minerals and other
nutrients being carried by the blood to escape into spaces between vessels and deprive the cells of their vital
needs to sustain life. When water in the blood is contaminated with chemicals, it enters the cells and changes
their structure, which in turn could lead to changes in DNA. This is the start of the disease process, which is
very similar to the aging process.
Infants prone for water loss due to greater volume of extracellular fluid, which can be lost by illness or
environmental conditions. As well as the infants and children are more vulnerable to fluid and electrolyte
imbalances due to
� A higher proportion of water content and a greater surface area.
� A greater proportion of fluid in the EC compartment
� A higher metabolic rate that increases the rate at which body water must be replenished
� Immature kidneys and an immature hemostatic regulation (buffer) system
� Greater insensible water loss
� An inability to shiver or sweat to control temperature
Composition of Body Fluids
ICF and ECF contain oxygen, dissolved nutrients, excretory products as CO2 and charged particles
called ions. Ions come from dissolved salts (eg. NaCl; sodium cholride breaks into Na+ (ion) and Cl- (ion)
these charged particles are called electrolytes because they can conduct electricity). The positive charge ion
called cation ( eg of cations Na+, K+, Mg+2) and the negative charge ion called anion( eg. Cl-, HCO3-,
HPO4-).
Electrolytes are measured in milliequivalents per liter of water ( mEq/L). Clinically the mEq system is
commonly used but not with all electrolytes, because the laboratory tests are usually performed using the
blood plasma (ECF) which reflect what is happening in the ECF, not what happens within the cells.
* Other body fluids such as gastric and intestinal secretions also contain electrolytes
Fluid and electrolytes – Developed by Khulood Shattnawi 3
Mechanisms of fluid movement:
Water is retained in the body in a relatively constant amount and, with few exceptions, is freely
exchangeable among all body fluid compartments. The proximity of the extravascular compartment to the
cells allows for continual change in volume and distribution of fluids, largely determined by solutes
(especially sodium) and physical forces. Transport mechanisms are the basis for all activity within the cells,
and since they have limited ability to store materials, movement in and out of cells must be rapid. Internal
control mechanisms (such as thirst, antidiuretic hormone (ADH), and aldosterone(which enhances sodium
reabsorption)) are responsible for distribution and maintenance of fluid balance.
1- Diffusion: molecules move from a solution of higher concentration to a solution of
lower concentration. This motion affected by temperature, size of molecules and the
concentration of the solution.
2- Hydrostatic pressure/ Filtration: movement of fluid and solutes from an area of
higher hydrostatic pressure to one of lower pressure. The pressure created by the
weight of fluids (increased pressure in the arteries forces fluids through the capillary
walls into the interstitial spaces).
3- Active Transport: movement of substance across the cell membrane from a less
concentration solution to higher concentrated by active transport (a carrier).
4- Osmotic pressure: water movement across the cell membranes from low solute
concentration (low osmotic pressure) to higher concentration of solute (high osmotic
pressure). Osmolality is the concentration of solutes in the body fluids, usually
reported as milliosmols per kilogram (mOsm/kg). Sodium is the greatest determinant
of serum osmolality. Example in hypernatremia where the serum Na results in water
movement from ICS to ECS, and the hyponatremia is the opposite.
Tonicity refers to the osmolality of solution:
1- Isotonic solution has the same osmolality as body fluids ( eg Normal saline 0.9%).
2- Hypertonic solution has a higher osmolality than body fluids ( eg Normal saline 3%).
3- Hypotonic solution has a lower osmolality than body fluids ( eg Normal saline
0.45%)
Factors Affecting Body Fluid, Electrolytes and Acid-Base Balance
1- age: infant has immature kidneys, rapid respiration and more body surface area than adult which make the
infant losses the fluid rapidly. In elderly people the thirst response often is blunted and kidney becomes less
able to conserve water that will affect the fluid balance.
2- Gender and Body Size: people with a higher percentage of body fat have less fluid.
3- Environmental Temperature: both salt and water are lost through sweating in hot climate
4- Lifestyle: diet, exercise, stress and alcohol consumption all affect the fluid and electrolyte balance
IMBALANCES
It occurs when body fluids are lost in excess of fluid gain. The great majority of disturbances in
hydration and electrolytes balance occur secondary to vomiting and diarrhea
Fluid Imbalances
I. Dehydration
Dehydration is the excessive loss of water from the body tissues. It is a common disturbance in infants
and children whenever total fluid output exceeds total fluid intake. Dehydration can be classified by type
or degree
Fluid and electrolytes – Developed by Khulood Shattnawi 4
Types of dehydration:
I. Isotonic /Isonatremic dehydration: occurs when fluids and electrolytes losses are in same
proportion as they exist in the body. Fluid osmolarity is not affected. And there is deficit of TBW.
This can be seen in 70% of children with diarrhea. Shock is the greatest threat to life in this type.
Plasma sodium remains within normal limits (130 – 150 mEq/L )
II. Hypertonic dehydration/hypernatremia (Plasma Na+ > 145 mEq / L):
When the water intake decreases and Na increases. Proportionally greater loss of water than Na. It
can occur when insensible loss of water from
skin and respiration tract is high. In this case
the Na increase the osmotic pressure in the
blood vessels that shifts the fluids from the IC
to the ECS. It is the most dangerous type.
The defence mechanism for this case are;
a. stimulation of thirst
b. stimulation of ADH.
10-20% of children with dehydration have
this type. The causes can be
a. Administration of hypertonic IV
fluids
b. Increase of Na intake
c. Failure of ADH
d. Increase of insensible loss of water as in burn, fever, respiratory infections
Clinical manifestations
• Thirst
• Lethargy
• Neurological dysfunction due to dehydration of brain cells
Treatment
• Lower serum Na+
– Isotonic salt-free IV fluid
III. Hypotonic/ Hyponatremia dehydration (Overall decrease in Na+ in ECF.
Plasma Na+ < 130 mEq/L): occurs when the electrolyte deficit exceeds the water
deficit. It can be caused by excessive plain water intake and defect in renal water
excretion. It can be also seen in cystic fibrosis due to excessive lose of Na via sweat.
The water shifts from ECS to ICS causing circulatory collapse. This type is occur in
10% of children with dehydration.
Clinical manifestations
• Neurological symptoms
– Lethargy, confusion, apprehension, depressed reflexes, seizures and coma
Fluid and electrolytes – Developed by Khulood Shattnawi 5
Sign Isotonic Hypotonic Hypertonic
Skin
Color
Temperature
Turgor
Feel
Gray
Cold
Poor
Dry
Gray
Cold
Very poor
Clammy
Gray
Cold or hot
Fair
Thickened
Mucus membranes Dry Slightly moist Parched
Tearing and salivation Absent Absent Absent
Eyeball Sunken Sunken Sunken
Fontanel Sunken Sunken Sunken
Body temperature Subnormal or
elevated
Subnormal or
elevated
Subnormal or elevated
Pulse Rapid Very rapid Moderately rapid
Respirations Rapid Rapid Rapid
Behaviour Irritable to lethargic Lethargic to
comatose;
convulsions
Marked lethargy with extreme
hyper-irritability on stimulation
Degrees of dehydration
1. Mild dehydration: loss up to 5% of preillness weight
2. Moderate dehydration: loss of 5% to 10% of preillness weight
3. Severe dehydration: loss of more than 10% of preillness weight
Clinical findings according to degree of dehydration
Degree of Dehydration
Sign Mild Moderate Severe
Fluid loss < 5% 5% to 9% >=10%
LOC Alert Irritable or lethargic Lethargic to comatose
Skin color Pale Gray Mottled
Skin turgor Decreased Poor Very poor
Mucous membrane Dry Very dry Parched
UOP Decreased Oliguria Marked oliguria
BP Normal Normal or lowered Lowered
Pulse rate Normal or increased Increased Rapid and thready
Capillary refill Normal (<2 sec) Delayed (2-3 sec) Delayed (> 3 sec)
Causes of dehydration are:
I) Lack of oral intake.
II) GI ; vomiting, diarrhea, malabsorption
III) Burns
IV) Fever
V) Diabetes mellitus
VI) Tachypnea as in bronchiolitis
Fluid and electrolytes – Developed by Khulood Shattnawi 6
Nursing process for the child with dehydration
� Assessment findings: depend on the degree of dehydration
� Clinical manifestations:
� Excessive thirst
� Fatigue
� Wt loss
� Depressed fontanelles
� Decreased UO
� Tachycardia & tachypnea
� Decreased blood pressure
� Skin:
� Temperature
� Dry skin and mucous membranes
� Poor turgor
� Sunken eyeballs; no tears
� Pale, ashen, cyanotic nail beds or
mucous membranes.
� Delayed capillary refill > 3 seconds
� Laboratory and diagnostic study findings:
� Urinalysis: concentrated urine with high specific gravity (> 1.030)
� CBC: Hgb and hct will be increased in extracellular fluid volume loss, and will be
decreased in extracellular fluid volume excess.
� BUN: elevated
� Electrolyte studies: decreased urine Na concentration and altered serum electrolyte
values
� ABGs: low serum pH value if acidotic
� Nursing diagnosis: deficient fluid volume
� Implementation:
� Assess child’s hydration status
� Accurate intake and output
� Daily weights: most accurate way to monitor fluid levels
� Hourly monitoring of IV rate and site of infusion.
� Administer I.V. fluids as ordered ( odium bicarbonate may be added to the I.V
solution to correct acidosis. Potassium is not added to the I.V line until kidney
function is ensured, not given if urine output less than 0.5 mg/kg/hour)
� Administer oral rehydration therapy and other fluids as prescribed to correct
fluid balance. Offer oral fluids in small quantities
� Withhold a full diet until the child is well hydrated
� Increase fluids if increase in vomiting or diarrhea.
� Decrease fluids when taking oral fluids or signs of edema.
Therapeutic management
Major goals are:
1. Assessment of the fluid and electrolyte imbalance
2. Rehydration
3. Maintenance fluid therapy
4. Reintroduction of adequate diet
Fluid and electrolytes – Developed by Khulood Shattnawi 7
Treatment of dehydration
Oral rehydration therapy (ORT) is one of the major worldwide health care advances of the past decade.
ORT is effective, safer, less painful, and less costly than intravenous fluids, thus ORT is the treatment of
choice for most cases of dehydration caused by diarrhea (50 ml / kg every 4 hours for mild cases
Increase to 100 ml / kg every 4 hours for moderate cases).
Oral rehydration solutions (ORSs) are successful in treating the great majority of infants with isotonic,
hypotonic, or hypertonic dehydration. Glucose-mediated, enhanced sodium absorption forms the
physiologic basis for the composition of these solutions. Recently, a rice-based ORS has been developed
as an alternative to the standard glucose ORS. These nutrient-based solutions may reduce vomiting,
decrease diarrheal volume loss, and shorten the duration of disease.
After rehydration in infants, an ORS may be used during maintenance fluid therapy by alternating the
solution with a low-sodium fluid such as water, breast milk or lactose-free formula. For older children, an
ORS can be given and a regular diet continued.
Ongoing stool losses should be replaced on a 1:1 bases with ORS. If the stool volume is not known,
approximately 10 ml/ kg or 1/2 to 1 cup of ORS should be given for each diarrheal stool.
Solutions for oral rehydration are useful in most cases of dehydration, and vomiting is not a
contraindication. A child who is vomiting should be given an ORS at frequent intervals and in small
amounts. For young children, the fluid can be given in a spoon or small syringe in 5- to 10-ml every 1 to 5
minutes. ORS may also be given by nasogastric or gastrostomy tube infusion in children who were
feeding with this modality for other reasons.
Early reintroduction of nutrients or continued feeding is desirable because of an improved nutritional
outcome and because it may reduce the number of stools, reduce weight loss and shorten the duration of
illness. Infants who are breastfeeding should continue breastfeeding; ORS should be used to replace
ongoing losses.
Intravenous fluids are required for severe dehydration and vomiting. Most common pediatric
maintenance solutions include a combination of dextrose (usually 5% or 10%) and NaCl (usually 0.22%
to 0.3%). The hypotonic solution is necessary for children, because their daily turnover of free water
exceeds that of adult. Because infants and young children are subject to rapid fluid shifts, any IV solution
given to them contains at least 0.2% NaCl to prevent brain edema, a disorder to which they are
susceptible if given plain water. Glucose is rapidly metabolized; therefore the osmolality of 5% glucose is
further diminished.
Situations may occur in which rapid establishment of a systemic access is vital and venous access may be
hampered by peripheral circulatory collapse, hypovolemic shock, cardiopulmonary arrest or other
conditions. Intraosseous infusion provides a rapid safe, and lifesaving alternate route for administration
of fluids and medications until intravascular access can be attained.
Total Parenteral Nutrition (TPN) therapy TPN provides complete nutrition for children who cannot
consume sufficient nutrients through gastrointestinal tact to meet and sustain metabolic requirements.
TPN solutions provide protein, carbohydrates, electrolytes, vitamins, minerals, trace elements and fats.
Treatment phases
(I) Deficit therapy
I) Initial therapy phase: to restores the circulation with severe dehydration. Ringer’s
lactated, saline solution, plasma or albumin can be given.
II) Repletion therapy: correct previous loss and provide therapy for normal and abnormal
ongoing losses. In this phase KcL can be added.
(II) Stabilization phase: maintenance and ongoing losses; oral intake may be resumed started with clear
fluid.
Fluid and electrolytes – Developed by Khulood Shattnawi 8
Total Parenteral Nutrition (TPN)
TPN provides complete nutrition for children who cannot consume sufficient nutrients through
gastrointestinal tact to meet and sustain metabolic requirements. TPN solutions provide protein,
carbohydrates, electrolytes, vitamins, minerals, trace elements and fats. TPN can be administered via IV or
catheter. Catheter can be inserted for neonate and infant through external or internal jugular vein to the
superior vena cava. And the catheter can be inserted for older children through the subclavian vein to superior
vena cava
Indicators for TPN are
i. Malnourished / long period without enternal feeding.
ii. Premature infant will need TPN sooner than older child.
iii. Major GI tract abnormalities
iv. Immune deficiency
v. Inflammatory bowel diseases
vi. Severe burns
vii. Renal failure
Fluid and electrolytes – Developed by Khulood Shattnawi 9
viii. AIDs.
Complications of TPN
� Sepsis: infection
� Liver dysfunction
� Respiratory distress from too –rapid infusion of fluids
Conditions that produce fluid and electrolyte imbalance
Gastrointestinal disorders: Diarrhea
Diarrhea is the frequent passage of loose, abnormally watery stools. Diarrhea may be mild, moderate, or
severe; acute or chronic; inflammatory or noninflammatory. The disorder is a manifestation of abnormal
water and electrolyte transport. Acute diarrhea is differentiated from chronic diarrhea by the fact that it
lasts fewer than 3 weeks in children or 4 weeks in infants. Acute diarrhea is one of the most common
problems in children younger than 5 years of age and is the leading cause of death in children of
developing countries.
Diarrhea is not managed by encouraging intake of clear fluids by mouth, such as fruit juices, carbonated
soft drinks and gelatine. These fluids usually have a high carbohydrate content, a very low electrolyte
content and a high osmolality. Caffeinated soda is avoided because caffeine is a mild diuretic and may
lead to increased loss of water and sodium. Chicken or beef broth is not given because it contains
excessive sodium and inadequate carbohydrate. A BRAT diet (bananas, rice, apples, and toast or tea) is
contraindicated for the child, and especially for the infant, with acute diarrhea because this diet has little
nutritional value (low in energy and protein), is too high in carbohydrates, and is low in electrolytes.
Etiology:
1. Acute diarrhea: Rotavirus is the most common cause of acute nonbacterial diarrhea
(gastroenteritis). Bacterial cause of acute diarrhea include Escherichia coli and
Salmonella and Shigella organisms. Other causes of acute diarrhea include other
infections (e.g. upper respiratory and urinary tract infection), overfeeding,
antibiotics, ingested toxins, irritable bowel syndrome, enterocolitis, and lactose
intolerance
2. Chronic diarrhea: usually is associated with one or more of the following:
a. Malabsorption syndromes
b. Anatomic defects
c. Allergic reactions
d. Lactose intolerance
e. Inflammatory response
f. Immunodeficiency
g. Motility disorders
h. Parasites
Nursing process for the child with diarrhea:
Physical Assessment should be focused on:
� Skin: color , temperature, moisture, edema, turgor
� Mucous membrance: color , moisture
� Eyes: firmness
� Fontanels (infants): firmness level
� Cardiovascular system: heart rate, peripheral pulses, blood pressure, capillary refill, venous
filling
� Respiratory system: respiratory rate and pattern, lung sounds
� Neurologic: level of consciousness (LOC), orientation, motor function, reflexes.
Fluid and electrolytes – Developed by Khulood Shattnawi 10
Clinical manifestations (based on severity of diarrhea):
� Mild diarrhea is characterized by a few loose stools without other symptoms.
� Moderate diarrhea is characterized by several loose or watery stools, elevated temperature,
vomiting and irritability, weight loss or failure to gain weight
� Severe diarrhea is characterized by numerous stools, signs of moderate to severe
dehydration, weak cry, irritability, purposeless movements, inappropriate responses, and
possibly lethargic or comatose appearance
� Associated signs and symptoms may include fever, nausea, vomiting and cough
Nursing diagnosis:
� Deficit fluid volume
� Imbalance nutrition; less than body requirements
� Risk for infection
� Impaired skin integrity
Teaching / Parent Instruction
� Ask for help
� If diarrhea or vomiting increases
� No improvement seen in child’s hydration status.
� Child appears worse.
� Child will not take fluids.
� NO URINE OUTPUT
Implementation (refer to accompanied nursing care plan for a child with gastroenteritis)
II- Overhydration
Edema ( increase the interstitial fluid volume)
Overhydration results when the body receives more fluid than it can excrete. This can occur in patients with
normal kidneys who receive intravenous fluids too rapidly. Also occurs in children who are receiving dialysis
and enema. An increase in ECF leads to increase in cardiovascular load & thus cardiac failure
Edema is the presence of excess fluid in the interstitial spaces. Early detection and management of edema are
essential. 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 in infants may first be seen around the eyes and in the presacral, occipital, or genital areas. In pitting
edema, after exerting gentle pressure with the finger, the nurse should notice an impression in the skin that
lasts for several seconds.
Assessment
Generalized edema can occur and is manifested by
swelling in the extremities, face, perineum and torso.
Loss of normal skin creases may be assessed. Daily
weights are more sensitive indicators of water gain or loss
and should be obtained. Abdominal girth measurement
changes may also be an indicator of edema in children.
Jugular vein distention and moist breathing sounds and
cough are another indicators for fluid overload. Pitting
Fluid and electrolytes – Developed by Khulood Shattnawi 11
edema may occur and can be assessed by pressing the fingertip against a bony prominence for 5 seconds. If
the tissue rebounds immediately on removing the finger the patient does not have pitting edema. A quick way
to determine the severity is to measure the degree of pitting edema (+1:2mm, +2:4mm, +3:6mm & +4:8mm
skin depression)
Safety Precautions to prevent fluid overload
◊ Use small bags of fluid or to control fluid volume.
◊ Check IV solution infusion against physician orders.
◊ Always use infusion pump so that the rate can be programmed and monitored.
◊ Even mechanical pumps can fail, so check the intravenous bag and rate frequently.
◊ Record IV rate q hour
Disturbances Electrolyte, and Acid-Base Balances
Electrolytes account for approximately 95% of the solute molecules in body water. Sodium Na+ is the
predominant extracellular cation. Potassium K+ is the predominant intracellular cation.
Many factors affect the fluid and electrolyte balance such as illness, 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:
I) Total body deficit or excess of fluid and electrolyte and the osmolality of the body is not affected.
II) When relationship between fluid and electrolyte has been altered and the osmolality is altered.
III) Or both
Electrolyte Imbalances
1- Potassium (95% of K of body in IC fluid)
High or low values can lead to cardiac arrest. With adequate kidney function excess potassium is excreted in
the kidneys. If kidneys are not functioning, the potassium will accumulate in the intravascular fluid
� Adults: 3.5 to 5.3 mEq /L
� Child: 3.5 to 5.5 mEq / L
� Infant: 3.6 to 5.8 mEq / L
� Panic Values: < 2.5 mEq /L or > 7.0 mEq / L
Hypokalemia: K < 3.5 mEq/L caused by vomiting, diarrhea and gastric suction, diuretics, alkalosis. The K
shifts from EC to IC space and also insulin promotes K to enter skeletal muscles and hepatic cells. Clinical
manifestations are; muscle weakness: neck flop, diminished bowel sounds, truncal weakness, limb weakness,
lethargy, cardiac arrhythemia, shallow breathing, polyuria and abdominal distention.
Causes of Hypokalemia:
� Vomiting / diarrhea
� Malnutrition / starvation
� Stress due to trauma from injury or surgery.
� Gastric suction / intestinal fistula
� Potassium wasting diuretics
Hyperkalemia : K > 5.0 : most commonly occur in children as a result of too rapid administration of IV
potassium chloride, and caused by acute and chronic renal failure, and glomerulonephritis. Significant
dysrhythmias and cardiac arrest may result when potassium levels arise above 6.0 mEq/L. Adequate intake of
fluids is important to insure excretion of potassium through the kidneys. Clinical manifestations include
malaise, muscle weakness, oliguria to anuria, abnormal cardiac function nausea, and diarrhea Nausea
Fluid and electrolytes – Developed by Khulood Shattnawi 12
Foods high in potassium
� Apricots, bananas, oranges, pomegranates, prunes
� Baked potato with skin, spinach, tomato
� Milk and yogurt
� Veal and fish
2- Calcium (serum Ca level= 4.0-5.5 mEq/L) calcium is requires for activation of numerous enzymes,
cardiac and neural and muscular functions
� Hypocalcemia
� Serum Ca level < 4.0 mEq/L
� Caused by: vitamin D deficiency, burns, infections, diarrhea, renal failure, inadequate dietary
intake, cow’s milk formula, hypoparathyroidism
� CM: tetany, neuromuscular irritability, convulsions, cardiac arrest, hypotension
� Hypercalcemia:
� Serum Ca level > 5.5 mEq/ L
� Caused by: increased administration of vit. D, prolong immobilization, hyperparathyroidism
� CM: N&V, constipation, flank pain, bradycardia, kidney stones, weakness and fatigue
C. Acid-Base Balance
� an acid is the substance releases hydrogen ions (H)
� Base (alkalis) is can accept hydrogen ions
� pH is the relative acidity or alkalinity of a solution: higher hydrogen ions more acidic which is low
pH. And less hydrogen ions more alkaline which is high pH.
� Body fluids are slightly alkaline
� normal pH of arterial blood is 7.35-7.45
� several body systems including buffers, the respiratory system, and the renal system are maintaining
the narrow pH
� The term acidosis and alkalosis refers to processes that cause acid and alkali to accumulate
� Acidosis/ Acidemia: results from either accumulation of acid or loss of base (drop in PH serum level
< 7.35)
� Alkalosis/ Alkalemia: results from either accumulation of base or loss of acid (rises in PH serum level
> 7.45)
Regulating acid-base
Acid-base balance is a dynamic relationship which reflects the concentration of hydrogen ions (H+) in the
body.
Hydrogen ions are acids which must be maintained within strict limits and any deviation from the norm
affects biochemical events.
pH : is the percentage of hydrogen ions (H) in a solution.
Acids: substances that donate hydrogen ions (H) to a solution. Ex: carbonic acid.
Bases: substances that accept hydrogen ions. Ex: bicarbonate (HCO3).
A solution with more base than acid has fewer hydrogen ions so has a higher pH. A pH ⟨ than 7 makes the
solution a base.
A solution that contains more acid than base has more hydrogen ions so has a lower pH. A pH ⟩ 7 makes the
solution an acid.
Fluid and electrolytes – Developed by Khulood Shattnawi 13
An alteration in the concentration of PaCO2 is termed respiratory disturbances because PCO2 is regulated by
the respiratory system (↑ in PaCO2→ respiratory acidosis, while ↓ in PaCO2→ respiratory alkalosis)
An alteration in the conc of the base HCO3 (bicarbonate) is termed metabolic (↑ in HCO3 →metabolic
alkalosis, while ↓ in HCO3 →metabolic acidosis)
Compensatory mechanisms regulating acid-base
BODY REGULATED ACID-BASE BALANCE BY: pH is regulated by (1) chemical buffers, (2) respiratory
system & (3) kidneys
1- Buffers: First system and the fastest performer, works in seconds
Buffered solution is one that contains a weak acid & its conjugate base, thus minimizing PH changes by
donating or absorbing H+ ions. Most important ECF buffer system is the bicarbonate HCO3 & carbonic acid
H2CO3. Haemoglobin, plasma proteins, phosphates, and bones are also effective buffers.
Bicarbonate ions combine with excess hydrogen ions to form carbonic acid in a dynamic relationship
HCO3 + H+ H2CO3 this carbonic acid is a weak volatile acid which must be eliminated
CO2 + H2O ↔ H2CO3 ↔ HCO3¯ +H+
The enzyme carbonic anhydrase causes the carbonic to convert to carbon dioxide and water.
The CO2 and H2O are easily eliminated by the lung and kidney.
The system also works in reverse.
2- Respiratory Regulation: regulating acid-base balance by eliminating or retaining carbon dioxide (CO2)
by altering the rate and depth of respirations.
- if the blood level of carbonic acid increase the rate and depth of respirations increase to excrete
carbon dioxide to fall the level of carbonic acid
- if the blood level of bicarbonate increase the rate and depth of respirations decrease to retained the
carbon dioxide 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 38-40 mmHg
3- Renal Regulation: kidneys maintain acid-base balance by excreting or conserving bicarbonate and
hydrogen ions
- if acidity increased the kidneys reabsorb and regenerate bicarbonate and excrete H
- in the case of alkalosis excess bicarbonate is excreted and H ion is retained
- normal serum bicarbonate level is 22-26 mEq/L
Normal arterial blood gas values
Blood Gas
Values
PH 7.35- 7.45
PaCO2 35 – 45 mmHg
HCO3 22 -26 mEq/L
O2 saturation 92 – 94%
Fluid and electrolytes – Developed by Khulood Shattnawi 14
Acid-Base Imbalances
The abnormalities in PCO2 increase or decrease is called respiratory alkalosis or acidosis because
PCO2 regulated by respiration
1. Increase in PCO2 ---------------- respiratory acidosis
2. Decrease in PCO2----------------respiratory alkalosis.
The abnormalities of plasma bicarbonate concentration refer to metabolic process
1. Increase in HCO3---------------------metabolic alkalosis
2. Decrease in HCO3------------------- metabolic acidosis
1- Respiratory Acidosis
Hypoventilation and CO2 retention cause carbonic acid level to increase which will drop the pH level
below 7.35. This can be caused by
� Aspiration, spasm of airway, laryngeal edema, epiglottitis, croup, pulmonary edema, cystic fibrosis,
and Bronchopulmonary dysplasia.
� Sedation overdose, head injury, or sleep apnea.
When respiratory acidosis occurs the kidneys will retain bicarbonate to restore the normal ratio of
bicarbonate: carbonic acid (20:1) in order to restore the normal pH.
Associated manifestations:
I) headache
II) blurred vision
III) restlessness
IV) anxiety
V) tremors
Medical Management
� Correction of underlying cause.
� Bronchodilators: asthma
� Antibiotics: infection
� Mechanical ventilation
� Decreasing sedative use.
2- Respiratory Alkalosis
Hyperventilation the CO2 is exhaled causing the carbonic acid to fall and rise the pH above 7.45. This
can be caused by
� Hypoxemia
� Anxiety
� Pain
� Fever
� Salicylate poisoning: ASA
� Meningitis
� Over-ventilation
With respiratory alkalosis the kidneys will excrete bicarbonate to return normal pH.
Fluid and electrolytes – Developed by Khulood Shattnawi 15
S&S
I) increase irritability of central and peripheral nervous system.
II) Light headache
III) Altered consciouness
IV) Paresthesia of extremities
V) arrhythmias
Management
� Stress management if caused by hyperventilation.
� Pain control.
� Adjust ventilation rate.
� Treat underlying disease process.
3-Metabolic Acidosis (diarrhea)
when bicarbonate is low in relation to the carbonic acid in the body , causing the pH to fall. This can
be caused by
I) Gain in acid: ingestion of acids, oliguria, starvation (anorexia), DKA, tissue hypoxia.
II) Loss of bicarbonate: diarrhea, intestinal or pancreatic fistula, or renal anomaly.
Metabolic acidosis will stimulate the respiratory center causing the rate and depth of respiration to
increase (in which the CO2 is eliminated and the carbonic acid is fall).
S&S
I) Increase depth of respiration
II) Arrhythmia
III) Lethargy----coma
IV) Impaired growth (rickets)
V) Wt loss
VI) Anorexia
VII) Muscle weakness and listlessness.
4- 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 causing losing in H.
Causes are
I) Muscles hypertonic
II) vomiting
III) nasogastric suctioning
IV) diuretics; decrease the ECF leaving HCO3 uncharged
V) Hypokalemia The metabolic alkalosis will stimulate the respiratory center to slow and shallow the
breathing (causing to retain CO2 which will increase the carbonic acid level).
VI) HCO3 retention may result from, massive blood transfusion, excessive administration of sodium
bicarbonate
S&S
i. Weakness
ii. Hypertonicity or tetany
iii. Dizziness
Fluid and electrolytes – Developed by Khulood Shattnawi 16
Summary of acid-base imbalances
Disorder
Respiratory
parameter PCO2
Metabolic
parameter HCO3
cause
Respiratory acidosis ↑ ↑
Hypoventilation
Respiratory alkalosis ↓ ↓
Hyperventilation
Metabolic acidosis ↓ ↓
Add acid or loss
of base
Metabolic alkalosis ↑ ↑
Add base or loss
of acid
Interpreting ABGs
Step 1. Evaluate the PH: acidemia or alkalemia.
Step 2. Evaluate ventilation: a PaCO2 greater than 45 indicates ventilatory failure and respiratory
acidosis. A PaCO2 less than 35 indicates alveolar hyperventilation and respiratory alkalosis
Step 3. Evaluate metabolic process: a bicarbonate (HCO3) less than 22 denotes metabolic acidosis.
HCO3 greater than 26 reflects metabolic alkalosis
Step 4. Determine primary & compensating disorder: when both the PaCO2 & the HCO3 are
abnormal, decide which is primary & which is compensating by checking the pH. Only a process of
acidosis can make the pH acidic, and only a process of alkalosis can make the pH alkaline.
Step 5. Evaluate oxygenation: a PaO2 between 60-80 mmHg reflect mild hypoxemia, between 40-60
moderate hypoxemia, and below 40 severe hypoxemia
There are 3 states of compensation
� Non-compensation: reflected in an alteration of only PaCO2 or HCO3
� Partial- compensation: in which both PaCO2 & HCO3 are abnormal and because compensation is
incomplete, the pH is also abnormal
� Complete-compensation: in which both PaCO2 & HCO3 are abnormal, but because compensation is
complete, the pH is normal. In this situation, to identify the primary disorder:
� Consider a pH between 7.35-7.40 indicative of primary acidosis
� A pH between 7.40- 7.45 indicative of primary alkalosis
Fluid and electrolytes – Developed by Khulood Shattnawi 17
NURSING CARE PLAN
The Child with Acute Diarrhea (Gastroenteritis)
Nursing Diagnosis: Fluid volume deficit related to excessive GI losses in stool or emesis
Patient Goal 1: Will exhibit signs of rehydration and maintain adequate hydration
• NURSING INTERVENTIONS/RATIONALES
Administer oral rehydration solutions (ORS) for both rehydration and replacement of stool losses (see Table
29-2)
Give ORS frequently in small amounts, especially if child is vomiting, because vomiting, unless severe, is
not a contraindication to using ORS
Administer and monitor IV fluids as prescribed for severe dehydration and vomiting
Administer antimicrobial agents as prescribed to treat specific pathogens causing excessive GI losses
After rehydration, offer child regular diet as tolerated because studies show that early reintroduction of
normal diet is beneficial in reducing number of stools and weight loss and shortening duration of illness
Alternate ORS with a low-sodium fluid such as water, breast milk, lactose-free formula, or half-strength
lactose-containing formula for maintenance fluid therapy (see Table 29-3)
Maintain strict record of intake and output (urine, stool, and emesis) to evaluate effectiveness of interventions
Monitor urine specific gravity every 8 hours or as indicated to assess hydration
Weigh child daily to assess for dehydration
Assess vital signs, skin turgor, mucous membranes, and mental status every 4 hours or as indicated to assess
hydration
Discourage intake of clear fluids such as fruit juices, carbonated soft drinks, and gelatin because these fluids
usually are high in carbohydrates, low in electrolytes, and have a high osmolality
Instruct family in providing appropriate therapy, monitoring intake and output, and assessing for signs of
dehydration to ensure optimum results and improve compliance with the therapeutic regimen
• EXPECTED OUTCOME
Child exhibits signs of adequate hydration (specify)
Nursing Diagnosis: Altered nutrition: less than body requirements related to diarrheal losses,
inadequate intake
Patient Goal 1: Will consume nourishment adequate to maintain appropriate weight for age
• NURSING INTERVENTIONS/RATIONALES
After rehydration, instruct breast-feeding mother to continue feeding breast milk because this tends to reduce
severity and duration of illness
Avoid giving BRAT diet (bananas, rice, apples, and toast or tea) because this diet is low in energy and
protein, too high in carbohydrates, and low in electrolytes
Observe and record response to feedings to assess feeding tolerance
Instruct family in providing appropriate diet to gain compliance with therapeutic regimen
Explore concerns and priorities of family members to improve compliance with therapeutic regimen
Fluid and electrolytes – Developed by Khulood Shattnawi 18
• EXPECTED OUTCOME
Child takes prescribed nourishment and exhibits a satisfactory weight gain
Nursing Diagnosis: Risk for infection related to microorganisms invading GI tract
Patient (others) Goal 1: Will not exhibit signs of gastrointestinal infection
• NURSING INTERVENTIONS/RATIONALES
Implement body substance isolation or other hospital infection-control practices, including appropriate
disposal of stool and laundry and appropriate handling of specimens to reduce risk of spreading infection
Maintain careful handwashing to reduce risk of spreading infection
Apply diaper snugly to reduce likelihood of fecal spread
Use superabsorbent disposable diapers to contain feces and decrease chance of diaper dermatitis
Attempt to keep infants and small children from placing hands and objects in contaminated areas
Teach children, when possible, protective measures such as handwashing after using toilet, and so on, to
prevent spread of infection
Instruct family members and visitors in isolation practices, especially handwashing, to reduce risk of
spreading infection
• EXPECTED OUTCOME
Infection does not spread to others
Nursing Diagnosis: Impaired skin integrity related to irritation caused by frequent, loose stools
Patient Goal 1: Skin will remain intact
• NURSING INTERVENTIONS/RATIONALES
Change diaper frequently to keep skin clean and dry
Cleanse buttocks gently with bland, nonalkaline soap and water or immerse child in a bath for gentle
cleansing because diarrheal stools are highly irritating to skin
Apply ointment such as zinc oxide to protect skin from irritation (type of ointment may vary for each child
and may require a trial period)
Expose slightly reddened intact skin to air whenever possible to promote healing; apply protective ointment
to very irritated or excoriated skin to facilitate healing
Avoid using commercial baby wipes containing alcohol on excoriated skin because they will cause stinging
Observe buttocks and perineum for infection, such as Candida, so that appropriate therapy can be initiated
Apply appropriate antifungal medication to treat fungal infection of skin
• EXPECTED OUTCOME
Child has no evidence of skin breakdown
Nursing Diagnosis: Anxiety/fear related to separation from parents, unfamiliar environment,
distressing procedures
Patient Goal 1: Will exhibit signs of comfort
• NURSING INTERVENTIONS/RATIONALES
Provide mouth care and pacifier for infants to provide comfort
Fluid and electrolytes – Developed by Khulood Shattnawi 19
Encourage family visitation and participation in care as much as the family is able, to prevent stress
associated with separation
Touch, hold, and talk to child as much as possible to provide comfort and relieve stress
Provide sensory stimulation and diversion appropriate for child's developmental level and condition to
promote optimum growth and development
• EXPECTED OUTCOMES
Child exhibits minimal signs of physical or emotional distress
Family participates in child's care as much as possible
Nursing Diagnosis: Altered family processes related to situational crisis, knowledge deficit
Patient (family) Goal 1: Family will understand about child's illness and its treatment and will be able to
provide care
• NURSING INTERVENTIONS/RATIONALES
Provide information to family about child's illness and therapeutic measures to encourage compliance with
therapeutic regimen, especially at home
Assist family in providing comfort and support to child
Permit family members to participate in child's care as much as they desire, to meet needs of both child and
family
Instruct family regarding precautions to prevent spread of infection
Arrange for posthospitalization health care for continued assessment and treatment
Refer family to a community health care agency for supervision of home care as needed
• EXPECTED OUTCOME
Family demonstrates ability to care for child, especially at home
Data from Wong DL: Whaley & Wong's Nursing Care of Infants and Children, ed. 6, St. Louis, 1999, Mosby,
Inc.