FLUIDS AND ELECTROLYTE PHYSIOLOGY Flashcards
What are the percentages of total body water (TBW) for a newborn, 1-3 years old, and adult?
“Newborn: 75-80%
1-3: 65%
Adult: 55-60%
What is the main cation and anion in the plasma?
“Main cation: Sodium
main Anion: Chloride
What is the main cation and anion in intracellular fluid (ICF)?
“Main cation: Potassium
Main Anion: Phosphorus
What is the percentage of extracellular fluid (ECF) for a newborn, 1-3 years old, and adult?
“Newborn: 45%
1-3: 25%
adult: 25%
What is the percentage of intracellular fluid (ICF) for a newborn, 1-3 years old, and adult?
“Newborn: 35%
1-3: 40%
adult: 40%
What happens to total body water (TBW) as a person ages?
“Total body water decreases with age
What is tonicity?
“Tonicity is a measure of the effective pressure gradient defined by the water potential of two solutions separated by a semi-permeable membrane.”
Define hypotonic solution and its effect on red blood cells.
“In a hypotonic solution RBC’s swell-lower concentration of olutes OUTSIDE the cell + BURSTINGG (LYSIS)
Define isotonic solution and its effect on red blood cells.
“In an isotonic solution, concentration of solutes EQUAL inside & outside
Define hypertonic solution and its effect on red blood cells.
“In a hypertonic solution, solute concentration is HIGHER OUTSIDE the cell= SHRINK(CRENATION)
What is the source of water loss in the body?
“Urine (60%)
Insensible loss (30%) skin & lungs
Stool (5%)
What are the goals of maintenance fluids?
● Prevent dehydration
● Prevent electrolyte disorders
● Prevent ketoacidosis
● Prevent protein degradation
How do you calculate maintenance fluid requirement for the first 10 kg of body weight in pediatrics?
multiply by 100 mL/kg”
How do you calculate maintenance fluid requirement for the second 10 kg of body weight in pediatrics?
” multiply by 50 mL/kg”
How do you calculate maintenance fluid requirement for the third 10 kg or remaining weight in pediatrics?
“multiply by 20 mL/kg”
What is the Holliday-Segar Method for maintenance fluid requirement for a weight of 3-10 kg?
“100 mL/kg”
What is the Holliday-Segar Method for maintenance fluid requirement for a weight of 11-20 kg?
“1000 mL + 50 mL/kg (for excess over 10 kg)”
What is the Holliday-Segar Method for maintenance fluid requirement for a weight greater than 20 kg?
“1500 mL + 20 mL/kg (for excess over 20 kg)”
How do you calculate daily maintenance fluid volume using the body weight method for a child weighing 0-10 kg?
“100 mL/kg”
How do you calculate daily maintenance fluid volume using the body weight method for a child weighing 11-20 kg?
“1000 mL + 50 mL/kg (for each kg >10 kg)”
How do you calculate daily maintenance fluid volume using the body weight method for a child weighing over 20 kg?
“1500 mL + 20 mL/kg (for each kg >20 kg)”
What is the main electrolyte in the extracellular fluid?
“Sodium (Na)”
What is the main electrolyte in the intracellular fluid?
“Potassium (K)”
Where is the majority of potassium found in the body?
“Potassium is mainly found in muscles and in small amounts in the plasma.”
What is the dietary potassium requirement?
“1-2 mEq/kg”
How do you calculate the sodium requirement for a 10 kg patient?
“Na requirement = 10 kg x 3 = 30 mEq/100 mL H2O”
How do you calculate the potassium requirement for a 10 kg patient?
“K requirement = 10 kg x 2 = 20 mEq/100 mL H2O”
What is the goal of deficit therapy?
“Restore intravascular volume and replace fluid losses from pathologic causes.”
How is oral rehydration therapy administered?
“Oral rehydration therapy is administered orally or via nasogastric tube (NGT) for patients who can tolerate it.”
When is parenteral (intravenous) fluid therapy used?
“Parenteral fluid therapy is used for patients who cannot drink or are vomiting
What are the fluid replacement therapy amounts for mild dehydration in a patient weighing <12 kg?
“50 mL/kg/8 hours.”
What are the fluid replacement therapy amounts for moderate dehydration in a patient weighing <12 kg?
“100 mL/kg/8 hours.”
What are the fluid replacement therapy amounts for severe dehydration in a patient weighing <12 kg?
“150 mL/kg/8 hours.”
What are the fluid replacement therapy amounts for mild dehydration in a patient weighing >12 kg?
“30 mL/kg/8 hours.”
What are the fluid replacement therapy amounts for moderate dehydration in a patient weighing >12 kg?
“60 mL/kg/8 hours.”
What are the fluid replacement therapy amounts for severe dehydration in a patient weighing >12 kg?
“90 mL/kg/8 hours.”
How should fluids be administered in moderate dehydration?
Give 1/4 in 1 hour
Give 3/4 in the next 7 hours
How should fluids be administered in severe dehydration?
Give 1/3 in 1 hour
Give 2/3 in the next 7 hours
What fluids are used for moderate dehydration?
Plain LRS,
PNSS D5 LRS
What fluids are used for severe dehydration?
Plain LRS,
PNSS D5 LRS
What are the signs of severe dehydration?
Mental status: Lethargy/
unconsciousness
- Sunken eyes
- Unable to drink or drink poorly
- Skin turgor: skin pinch goes back
very slowly (≥2 seconds)
What are the signs of some dehydration?
Restlessness, irritability
- Sunken eyes
- Drinks eagerly, thirsty
What defines no dehydration?
“Not enough signs to classify as some or severe dehydration.”
What is the first step in managing dehydration?
“Assess the patient according to the level of dehydration—mild, moderate & severe
What is the formula for computing fluid replacement therapy for a patient under 12 kg with mild dehydration?
“Wt (kg) x 50 mL/kg/8 hours.”
What is the formula for computing fluid replacement therapy for a patient over 12 kg with mild dehydration?
“Wt (kg) x 30 mL/kg/8 hours.”
How should a patient be reassessed after 8 hours of fluid replacement therapy?
“If dehydration has resolved
What are the sources of water loss in the gastrointestinal system?
Diarrhea, vomiting, nasogastric
suctioning, ostomies
What are the sources of water loss in the renal system?
Diuretics, tubular-concentrating
disorders, adrenal insufficiency, diabetes
insipidus
What are the sources of water loss in the skin?
Burns, sweat losses in endurance
exercise, fever
What are the sources of water loss in third spacing?
Intestinal obstruction, bleeding (trauma
patients, massive bleeding), sepsis,
anaphylaxis
What are the sources of water loss from inadequate fluid intake?
Physical impairment, altered mental
status, dysphagia
What factors increase water needs from the skin?
radiant warmer
Phototherapy
Fever
Sweat
Burns
What factors decrease water needs from the skin?
“Incubator (for premature infants).”
What factors increase water needs from the lungs?
“Tachypnea & Tracheostomy
What factors decrease water needs from the lungs?
“Humidified ventilator.”
What factors increase water needs from the GIT?
“Diarrhea
Emesis
Nasogastric
suction
What factors increase water needs from the renal system?
“Polyuria.”
What factors decrease water needs from the renal system?
“Oliguria/anuria.”
What factors increase water needs from miscellaneous sources?
“Surgical drain
What is parenteral fluid therapy?
“Parenteral fluid therapy involves intravenous administration of crystalloids colloids, or blood products
What are crystalloids?
“Crystalloids are aqueous solutions with varying concentrations of electrolytes and are most commonly used fluids in a hospital setting.”
What is the main purpose of crystalloids?
“Crystalloids increase intravascular volume.”
What are colloids?
“Colloids are high molecular weight substances that remain in the intravascular compartment longer than crystalloids
What is the disadvantage of using colloids for extended periods?
“Colloids generate oncotic pressure and decrease blood coagulability.”
What is the cost difference between crystalloids and colloids?
“Colloids are more expensive than crystalloids.”
What is the use of albumin in fluid therapy?
“Albumin is used in cases of nephrotic syndrome and to remove excess fluid in patients with edema or anasarca.”
When are colloids typically used?
“Colloids are the fluid of choice when there is a need for rapid fluid replacement
What are the components of intravenous fluids?
“Intravenous fluids may contain sodium (Na)
What are standard oral rehydration solutions (ORS) used for?
“ORS is used in patients who can drink water and are not vomiting but still need fluid replacement.”
What is the concern with standard ORS solutions?
“Standard ORS contains high levels of glucose
What is the purpose of reduced osmolarity ORS?
“Reduced osmolarity ORS is developed to avoid inducing dehydration while still providing effective fluid replacement.”
What are some examples of ORS solutions?
“Examples include Glucolyte plus
Which ORS solution is commonly used for patients with diarrhea?
“Glucolyte plus
What is a home fluid option that has osmolarity similar to ORS?
“Coconut water has osmolarity similar to reformulated ORS.”
