Alteration in Fluid and Electrolyte Status Lecture notes

Fluid and Electrolytes
Alteration in Fluid and Electrolyte Status Lecture notes

Developmental and Biological Variances
 Infants younger than 6 weeks do not produce tears.
 In an infant a sunken fontanel may indicate dehydration.
 Infants are dependant on others to meet their fluid needs.
 Infants have limited ability to dilute and concentrate urine.

Developmental and Biological
 The small the child, the greater the proportion of body water to weight and proportion of extracellular fluid to intracellular fluid.
 Infants have a larger proportional surface are of the GI tract than adults.
 Infants have a greater body surface area and higher metabolic rate than adults.
Water Balance
 Regulated by Anti-diuretic Hormone ADH.
 Acts on kidney tubules to reabsorb water.
 The young infant is highly susceptible to dehydration.

Increased Water Needs
 Fever
 Vomiting and Diarrhea
 High-output in renal failure
 Diabetes insipidus
 Burns
 Shock
 Tachypnea

Decreased Water Needs
 Congestive Heart Failure
 Mechanical Ventilation
 Renal failure
 Head trauma / meningitis

General Appearance
 How does the child look?
 Skin:
• Temperature
• Dry skin and mucous membranes
• Poor turgor, tenting, dough-like feel
• Sunken eyeballs; no tears
• Pale, ashen, cyanotic nail beds or mucous membranes.
• Delayed capillary refill > 3 seconds
Loss of Skin Elasticity

Cardiovascular
 Pulse rate change:
 Note rate and quality: rapid, weak, or thready
 Bounding or arrhythmias
 Tachycardia #1 sign that something is wrong
 Increased HR may be first subtle sign of hypovolemia
 Blood Pressure
 Note increase or decrease (remember it takes a 25% decrease in fluid or blood volume for change to occur)
Respiratory
 Change in rate or quality
 Dehydration or hypovolemia
 Tachypnea
 Apnea
 Deep shallow respirations
 Fluid overload
 Moist breath sounds
 Cough

Diagnostic Tests
 Make sure free flowing specimen is obtained, a hemolyzed or clotted specimen may give false values.
Hemoglobin and Hematocrit
 Measures hemoglobin, the main component of erythrocytes, which is the vehicle for transporting oxygen.
 Hgb and hct will be increased in extracellular fluid volume loss.

 Hgb and hct will be decreased in extracellular fluid volume excess.
Electrolytes
 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.

Potassium
 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
Potassium
 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:
<> 7.0 mEq / L

Hyperkalemia
 Defined as potassium level above 5.0 mEq / L
 Significant dysrhythmias and cardiac arrest may result when potassium levels arise above 6.0 mEq/L
 Adequate intake of fluids to insure excretion of potassium through the kidneys.

CM: Hyperkalemia
 Nausea
 Irregular heart rate
 Pulse slow / irregular
Causes of Hyperkalemia
 Acute renal failure
 Chronic renal failure
 Glomerulonephritis

Diagnostic tests:
 Serum potassium
 ECG
 Bradycardia
 Heart block
 Ventricular fibrillation

Hypokalemia
 Potassium level below 3.5 mEq / L
 Before administering make sure child is producing urine.
 A child on potassium wasting diuretics is at risk – Lasix
CM: Hypokalemia
Neuromuscular manifestations are: neck flop, diminished bowel sounds, truncal weakness, limb weakness, lethargy, 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
 Ingestion of large amounts of ASA

Foods high in potassium
 Apricots, bananas, oranges, pomegranates, prunes
 Baked potato with skin, spinach, tomato, lima beans, squash
 Milk and yogurt
 Pork, veal and fish
Monitor Potassium Levels

Sodium
 Sodium is the most abundant cation and chief base of the blood.
 The primary function is to chemically maintain osmotic pressure and acid-base balance and to transmit nerve impulses.
 Normal values: 135 to 148 mEq / L

Hyponatremia
 Reflects an abnormal rate of sodium to water and is defined as a serum sodium concentration less than 135 mEq/L.
 Results from retention of water secondary to impairment in free water excretion.

Pathophysiology
 When sodium levels drop in the fluids outside the cells, water will sweep into the cells in an attempt to balance the concentration of salt outside the cells.
 Cells will swell as the result of the excess water.
 Brain cells cannot accommodate – symptoms of hyponatremia result from brain swelling

Diagnosis
 10 to 15% of patients
 Vomiting, diarrhea, or excessive sweating
 Vital Signs: BP (orthostatic), skin turgor, mucous membrane appearance, jugular vein distention, edema
 Lab values
 History of oral intake of low-electrolyte or electrolyte free fluids

Early Manifestations
 Anorexia, nausea, lethargy and apathy
 More advanced symptoms: disorientation, agitation, seizures, depressed reflexes, focal neurological deficits
 Severe: coma and seizures: sodium concentration less than 120 mEq/L
Medical Management
 Normal saline given as resuscitative fluid
 May need to reduce the fluid rate to 75% of maintenance
 Supplemental oxygen
 Water and salt restrictions

Hypernatremia
 Serum sodium greater than 150 mEq/L is caused by conditions that produce an excessive gain of sodium or excessive loss of water that is greater than the loss of sodium.
Clinical Pearl
 Most infant with severe dehydration have a history of lethargy, listlessness, and decreased responsiveness; those with hypernatremia dehydration tend to be irritable and fussy.

Hypernatremia
 Inadequate fluid intake – 75%
 Gastrointestinal losses – 44%
 Occurs primarily in infants with diarrhea dehydration
 Diabetes insipidus was major reason for excessive urinary output
 Loss from high fever, environmental temperatures and hyperventilation

Primary Sodium Excess
 Improperly mixed formula or re-hydration solution
 Ingestion of sea water
 Hypertonic saline IV
 High breast milk sodium

Primary Water Deficit
 Diabetes Insipidus
 Diabetes Mellitus
 Gastroenteritis (water loss greater than solute loss)
 Inadequate breast feeding
 Withholding of water: handicapped
 Increased insensible loss – premature infant

Treatment Modalities
Intraosseous Therapy
Central Venous Catheter

Total Parental 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.

Complications of TPN
 Sepsis: infection
 Liver dysfunction
 Respiratory distress from too –rapid infusion of fluids
TPN: care reminder
caREminder:
 The TPN infusion rate should remain fairly constant to avoid glucose overload. The infusion rate should never be abruptly increased or decreased.

Dehydration
General Assessment
 Loss of weight
 Level of consciousness
 Alert to irritable
 Restless to lethargic
 Lethargic to coma
Skin Turgor
 In moderate dehydration the skin may have a doughy texture and appearance.

 In severe dehydration the more typical “tenting” of skin is observed.
Skin Turgor

Urine Output
 Normal urine output is 1-2 mL/kg/hr
 In mild dehydration urine output may be low – parent may report decrease in voiding
 Moderate dehydration urine output would be low and concentrated (oliguric) with elevated specific gravity.
 Severe dehydration would by (anuric) very low – very concentrated urine with high S.G.

Vital Signs
 The heart rate is the most sensitive indicator of dehydration / hypovolemia.
 HR will be elevated in an attempt to compensate for fluid loss.
 Blood pressure will only drop as child is severely dehydrated (>10%).
Treatment of Mild to Moderate
 ORT – oral re-hydration therapy
 50 ml / kg every 4 hours
 Increase to 100 ml / kg every 4 hours
 Non carbonated soda, jell-o, fruit juices or tea.
 Commercially prepared solutions are the best.

Re-hydration Therapy
 Increase po fluids if diarrhea increases.
 Give po fluids slowly if vomiting.
 Stop ORT when hydration status is normal
 Start on BRAT diet
 Bananas
 Rice
 Applesauce
 Toast


Teaching / Parent Instruction
 Call PMD
 If diarrhea or vomiting increases
 No improvement seen in child’s hydration status.
 Child appears worse.
 Child will not take fluids.
 NO URINE OUTPUT

Moderate to Severe Dehydration
Fluid replacement

 Isotonic fluids initially:

 Normal Saline 0.9%
 Followed by: Dextrose 5% in.45 NS

Potassium is added only after child has voided.

Nursing Interventions
 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.
 Increase fluids if increase in vomiting or diarrhea.
 Decrease fluids when taking po fluids or signs of edema.

Care Reminder
 A severely dehydrated child will need more than maintenance to replace lost fluids. 1 ½ to 2 times maintenance.
 Adding potassium to IV solution.
 Never add in cases of oliguria / anuria
• Urine output less than 0.5 mg/kg/hour
 Never give IV push
 Double check dosage

Over hydration
 Occurs when child receives more IV fluids that needed for maintenance.
 In pre-existing conditions such as meningitis, head trauma, kidney shutdown, nephrotic syndrome, congestive heart failure, or pulmonary congestion.

Signs and Symptoms
 Tachypnea
 Dyspnea
 Cough
 Moist breath sounds
 Weight gain from edema
 Jugular vein distention
Safety Precautions
 Use small bags of fluid or buretrol 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

Acid – Base Imbalances
Acidosis:
 Respiratory acidosis is too much carbonic acid in body.
 Metabolic Acidosis is too much metabolic acid.
Alkalosis.
 Respiratory alkalosis is too little carbonic acid.
 Metabolic alkalosis is too little metabolic acid.
Respiratory Acidosis
 Caused by the accumulation of carbon dioxide in the blood.
 Acute respiratory acidosis can lead to tachycardia and cardiac arrhythmias.
Causes of Respiratory Acidosis
 Any factor that interferes with the ability of the lungs to excrete carbon dioxide can cause respiratory acidosis.
 Aspiration, spasm of airway, laryngeal edema, epiglottitis, croup, pulmonary edema, cystic fibrosis, and Bronchopulmonary dysplasia.
 Sedation overdose, head injury, or sleep apnea.

Medical Management
 Correction of underlying cause.
 Bronchodilators: asthma
 Antibiotics: infection
 Mechanical ventilation
 Decreasing sedative use.
Respiratory Alkalosis
 Occurs when the blood contains too little carbon dioxide.
 Excess carbon dioxide loss is caused by hyperventilation.
Causes of hyperventilation

 Hypoxemia
 Anxiety
 Pain
 Fever
 Salicylate poisoning: ASA
 Meningitis
 Over-ventilation

Management
 Stress management if caused by hyperventilation.
 Pain control.
 Adjust ventilation rate.
 Treat underlying disease process.

Metabolic Acidosis
 Caused by an imbalance in production and excretion of acid or by excess loss of bicarbonate.
Causes:
 Gain in acid: ingestion of acids, oliguria, starvation (anorexia), DKA or diabetic ketoacidosis, tissue hypoxia.
 Loss of bicarbonate:
diarrhea, intestinal or pancreatic fistula, or renal anomaly.

Ingestion of large doses of Aspirin
Management
 Treat and identify underlying cause.
 IV sodium bicarbonate in severe cases.
 Assess rate and depth of respirations and level of consciousness.

Metabolic Alkalosis
 A gain in bicarbonate or a loss of metabolic acid can cause metabolic alkalosis.
Causes:
 Gain in bicarbonate:
Ingestion of baking soda or antacids.
Loss of acid:
Vomiting, nasogastric suctioning, diuretics massive blood transfusion

Clinical Manifestations
 Hypertonicity or tetany
 Management: Correct the underlying condition