BODY FLUIDS AND ELECTROLYTES Flashcards
a delicate balance of fluids, electrolytes, and acids and bases maintained in the body.
Homeostasis
- approximately 60% of average healthy adult’s weight (70% to 80% in infants and 50% to people older than 50)
- is the primary body fluid
Water
TWO COMPARTMENTS OF BODY’S FLUID
- INTRACELLULAR FLUID (ICF)
- EXTRACELLULAR FLUID (ECF)
found within the cells of the body; 2/3 of the total body fluid in adults.
INTRACELLULAR FLUID (ICF)
found outside the cells; 1/3 of the total body fluid
EXTRACELLULAR FLUID (ECF)
Types of Extracellular Fluid (ECF)
Intravascular Fluid (Plasma)
Interstitial Fluid
20% of the ECF; found within the vascular system
INTRAVASCULAR FLUID (PLASMA)
75% of the ECF; surrounds the cells
INTERSTITIAL FLUID
Composition of Body Fluids
Ions
Cations
Anions
Electrolytes
Charged particles
Ions
ions that carry a positive charge
Cations
ions that carry a negative charge
Anions
minerals in the body that have electrical charge; chemicals from which ions are made
Electrolytes
Group of Cations
Sodium (Na+)
Potassium (K+)
Calcium (Ca++)
Magnesium (Mg++)
Group of Anions:
Chloride (Cl-)
Bicarbonate (HCO3-)
Phosphate (HPO4–)
Sulfate (SO4–)
Electrolytes are generally measured in
milliequivalents per Liter of water (mEq/L) or milligrams per 100 milliliters (mg/100mL)
4 Movements of body Fluid and Electrolyte
Osmosis
Diffusion
Filtration
Active Transport
Movement of water across cell membranes, from the less concentrated solution to the more concentrated solution
Osmosis
substances dissolved in a liquid.
Solute
component that can dissolve a solute.
Solvent
the concentration of solutes in body fluids; solute per kilogram of water
Osmolality
power of a solution to draw water across a semipermeable membrane
Osmotic Pressure
pulls water from the interstitial space into the vascular compartment.
Colloid Osmotic Pressure
solute and solvent are equal.
Isotonic Solution
higher osmolality than body fluids; cells shrink
Hypertonic Solution
lower osmolality than body fluids; cells swell
Hypotonic solution
Movement of molecules through a semipermeable membrane from an area of higher concentration to an area of lower concentration
Diffusion
Fluid and solutes move together across a membranes from an area of higher pressure to one of lower pressure.
Filtration
pressure in the compartment that results in the movement.
Filtration Pressure
pressure exerted by a fluid within a closed system on the walls of the container in which it is contained.
Hydrostatic pressure
Substances can move across cell membranes from a less concentrated solution to a more concentrated one
It differs from diffusion and osmosis in that metabolic energy is expended.
Active Transport
3 REGULATING BODY FLUIDS
Fluid Intake
Fluid Output
Maintaining Homeostasis
Fluid Intake
An average adult needs ___ mL per day.
2,500 mL per day.
– primary regulator of fluid intake
- thirst center is located in the hypothalamus of the brain.
- it takes 30 minutes to 1 hour for the fluid to be absorbed and distributed throughout the body
Thirst mechanism
4 Homeostatic regulators/mechanisms:
- Kidneys
- Antidiuretic Hormone
- Renin-Angiotensin-Aldosterone System
- Atrial Natriuretic Factor
Primary regulator of body fluids and electrolyte balance.
Regulates water and electrolyte secretion
Kidney
Kidney,Plays a significant role in ____, excreting hydrogen ion (H+) and retaining bicarbonate.
acid-base regulation
Regulates water excretion from the kidney
Synthesized in the anterior portion of the hypothalamus
Antidiuretic Hormone (ADH)
Antidiuretic Hormone (ADH)
Produced when _______; conversely, ADH is suppressed when serum osmolality decreases
Restore blood volume (and renal perfusion) through sodium and water retention
Renin-Angiotensin-Aldosterone System
Released from cells in the atrium of the heart in response to excess blood volume and stretching the atrial walls.
Reduces thirst, reducing fluid intake
Atrial Natriuretic Factor (ANF)
Atrial Natriuretic Factor (ANF), Promotes sodium wasting and acts as a ____, thus reducing vascular volume.
potent diuretic
Importance of electrolytes:
Maintaining fluid balance
Contributing to acid-base regulation
Facilitating enzyme reactions
Transmitting neuromuscular reactions
Electrolytes
Sodium (Na+)
Potassium (K+)
Calcium (Ca++)
Magnesium (Mg++)
Chloride (Cl-)
Phosphate (PO4-)
Bicarbonate (HCO3-)
Most abundant cation in the ECF and a major contribution to serum osmolality.
Aids in transmitting nerve impulses and contracting muscles
28
Sodium (Na+)
Normal value: 135-145 mEq/L
Sodium (Na+)
Major cation in ICF, with only small amount found in ECF.
Vital electrolyte for skeletal, cardiac, and smooth muscle activity.
Potassium (K+)
Normal serum levels: 3.5 to 5.0 mEq/L
Potassium (K+)
99% of it is found in the skeletal system, with a relatively small amount in the ECF.
Vital in regulating muscle contraction and relaxation, neuromuscular function, and cardiac function.
Calcium (Ca++)
Normal total serum levels: 8.5-10.5 mg/dL
Normal ionized serum levels: 4-5 mg/dL
Calcium (Ca++)
_____ and _____ increase serum Ca++ levels;
_____ decreases serum levels
Parathyroid hormone and calcitriol increase
calcitonin
Primarily found in the skeleton and in ICF
Second most abundant ICF cation
Aids in relaxing muscle contractions, transmitting nerve impulses, regulating cardiac function, and intracellular metabolism.
Magnesium (Mg++)
Normal serum levels: 1.5 to 2.5 mEq/L
Magnesium (Mg++)
Major anion of the ECF
When sodium is reabsorbed in the kidney, chloride usually follows.
Major component of gastric juice (HCl), and is involved in regulating acid-base balance.
Chloride (Cl-)
Normal serum levels: 95 to 108 mg/dL
Chloride (Cl-)
Major anion of ICF
Also found in the ECF, bone, skeletal muscle, and nerve tissue.
Aids in metabolizing Carbohydrate, Protein, and Fat; it is absorbed in the intestines
Phosphate (PO4-)
Normal serum levels: 2.5 to 4.5 mg/dL
Phosphate (PO4-)
Present in both ICF and ECF
Regenerated by the kidneys
Bicarbonate (HCO3-)
Primary function is to regulate acid-base balance (major body buffer)
Bicarbonate (HCO3-)
substance that releases hydrogen ions (H+)
Acid
have a low hydrogen ion concentration and can accept hydrogen ions in solution.
Bases (Alkalis)
the relative acidity or alkalinity of a solution
-reflects the hydrogen ion concentration of the solution (inversely proportional)
-normal pH: 7.35-7.45
pH
REGULATION OF ACID-BASE BALANCE
Buffers
Respiratory Regulation
Renal Regulation
prevent excessive changes in pH by removing or releasing hydrogen ions.
Buffer
Major buffer systems in the ECF:
Bicarbonate (HCO3-) –acid buffer; opponent of acids
Carbonic acid (H2CO3) –weak acid
TO ACHIEVE NORMAL pH
1 part Carbonic Acid (1.2 mEq/L) : 20 parts bicarbonate (24 mEq/L)
adding a strong acid in the ECF, depleting the bicarbonate and lowering the pH levels.
Acidosis
adding a strong base to the ECF, depleting carbonic acid as it combines with the base, increasing the pH levels.
ALKALOSIS
The lungs help regulate acid-base balance by eliminating or retaining Carbon Dioxide (CO2), a potential acid
RESPIRATORY REGULATION
formula to get Carbonic acid (H2CO3)
Carbon Dioxide (CO2) + Water (H2O)
High Carbonic acid (H2CO3) and CO2 levels =
respiration rate and depth increases, exhaling CO2 and decreasing carbonic acid levels
High Bicarbonate (HCO3-) levels =
the respiration rate and dept are reduced, retaining CO2 and increasing carbonic acid levels
Kidneys are the ultimate long-term regulator of acid-base balance, although slower to respond to changes.
Kidneys regulate pH by reabsorbing and regenerating bicarbonate and hydrogen ions
RENAL REGULATION
formula for Carbonic acid (H2CO3)
Hydrogen ion (H+) + Bicarbonate (HCO3-)
RENAL REGULATION
High H+ ions (acidic) = kidneys reabsorb and regenerate bicarbonate and excrete hydrogen ions
kidneys reabsorb and regenerate bicarbonate and excrete hydrogen ions
RENAL REGULATION
Low H+ ions (alkalosis) =
excess bicarbonate is excreted and H+ ion is retained
FACTORS AFFECTING BODY FLUID, ELECTROLYTES, AND ACID-BASE BALANCE:
Age
Gender and Body Size
Environmental Temperature
Lifestyle
Fluid Imbalances
Two basic types:
Isotonic
Osmolar
water and electrolytes are lost or gained in equal proportions
Isotonic
loss or gain of only water, so that the osmolality of the serum is altered (electrolytes are concentrated)
Osmolar
Four Categories of Fluid Imbalances
Fluid Volume Deficit
Fluid Volume Excess
Dehydration (hyperosmolar imbalance)
Overhydration (hypo-osmolar imbalance)
Fluid Volume Deficit (FVD) is the body loses both water and electrolytes from the ECF (intravascular compartment) in similar proportions, so it often is called
hypovolemia
Fluid Volume Deficit (FVD)/Hypovolemia Causes
Abnormal losses through the skin, GI tract, kidney
Movement of fluid in a third space (area that deems the fluid unavailable for us)
Fluid Volume Excess (FVE) is
The body retains both water and sodium in similar proportions to normal ECF, often called
hypervolemia
Fluid Volume Excess (FVE)/hypervolemia Causes
Increased intake of NaCl (sodium level is still normal, since both water and sodium are equally retained)
Infusion of sodium-containing fluids rapidly
Disease processes (heart failure, kidney failure, liver cirrhosis)
excess interstitial fluid
Edema
leaves a small depression or pit after finger pressure is applied
Pitting Edema
Water is lost from the body, leaving the client with excess sodium
Sodium levels are increased
Cells are dehydrated/shrunk
Dehydration
Dehydration Causes
○Diabetic Ketoacidosis (DKA)
○Osmotic diuresis
○Administration of hypertonic solutions
Water is gained in excess of electrolytes, resulting in low serum osmolality and low serum Na+ levels
Cells are swollen
Can lead to cerebral edema and impaired neurologic function
Overhydration (hypo-osmolar imbalance)
Overhydration (hypo-osmolar imbalance) Causes:
Causes:
○Syndrome of Inappropriate Anti-Diuretic Hormone (SIADH)
○Head Injury
ELECTROLYTE IMBALANCES: Sodium
Hyponatremia
Hypernatremia
ELECTROLYTE IMBALANCES: Potassium
Hypokalemia
Hyperkalemia
ELECTROLYTE IMBALANCES: Calcium
Hypocalcemia
Hypercalcemia
ELECTROLYTE IMBALANCES: Magnesium
Hypomagnesemia
Hypermagnesemia
ELECTROLYTE IMBALANCES: Chloride
Hypochloremia
Hyperchloremia
ELECTROLYTE IMBALANCES: Phosphate
Hypophosphatemia
Hyperphosphatemia
Classified as: respiratory or metabolic
Carbonic acid levels are normally regulated by the lungsthrough the retention/excretion of CO2 (respiratory acidosis or alkalosis)
Acid-base imbalances
____ are regulated by the kidneys(metabolic acidosis or alkalosis)
Bicarbonate and Hydrogen ion levels
Hypoventilation and CO2 retention cause carbonic acid to increase and the pH to fall below 7.35
RESPIRATORY ACIDOSIS
This causes the kidneys to retain bicarbonate to restore the normal carbonic acid to bicarbonate ratio
◎
May require hours to days to restore the normal pH
RESPIRATORY ACIDOSIS
When a person hyperventilates, exhaling more CO2 and decreasing carbonic acid levels = pH greater than 7.45
Causes: psychogenic or anxiety-related hyperventilation
Kidneys will excrete bicarbonate
RESPIRATORY ALKALOSIS
When bicarbonate levels are low in relation to the amount of carbonic acid = decreased pH
Stimulates the respiratory center = increase depth and rate of respirations; CO2 is eliminated and carbonic acid falls
METABOLIC ACIDOSIS
Causes: renal failure, inability of the kidneys to excrete H+, diabetic ketoacidosis
METABOLIC ACIDOSIS
The amount of bicarbonate in the body exceeds to the normal ratio
Causes: ingestion of NaHCO3 as an antacid, vomiting (loss of HCl)
METABOLIC ALKALOSIS
Depresses the respiratory rate (slow and shallow) = CO2 is retained and carbonic levels increases
METABOLIC ALKALOSIS
CLINICAL MEASUREMENTS
Daily Weights
Vital Signs
Fluid Intake and Output
◎ Serum electrolytes
◎ Urine pH
◎ Urine specific gravity
◎ Urine Sodium and Chloride excretion
◎ Arterial Blood Gases (ABGs)
LABORATORY TESTS
- measures the acidity, or
pH, and the levels of oxygen (O2) and carbon dioxide
(CO2) from an artery.
Arterial Blood Gases (ABGs)
Types of Intravenous Fluids
- Hypertonic solution – concentrated with solute,
expanding vascular volume - Hypotonic solution – less solutes, for treatment of
cellular dehydration - Isotonic solution –
solute = plasma
adequate fluids, consumption of a
balanced diet
Promote Wellness
Enteral Fluid and Electrolyte Replacement
- Fluid intake modifications
- Dietary changes
- Oral electrolyte supplements
Sodium Chloride
Normal Saline
Sodium, chloride, potassium, calcium
Ringer’s solution
Sodium, chloride,
potassium, calcium, and lactate (metabolized in the liver
to form bicarbonate)
Lactated Ringer’s solution
dextran, plasma, albumin
- used for severe blood/plasma loss
Volume expanders
Milliliters per hour – hourly rate of the fluid (cc/hr) formula
cc/hr = total infusion volume/
total infusion time
Drops per minute – gtts/min formula
gtts/min = total infusion volume x drop factor/
total time of infusion in minutes
number of drops delivered per mL of
solution (gtts/mL)
- printed on the package of the infusion set
Drop factor
Venipuncture sites:
commonly
used for intermittent or
continuous infusions
Metacarpal
basilic
cephalic veins
inserted in the subclavian or
jugular vein, with the distal tip
resting in the SVC.
Central Venous Catheters
inserted in basilic or
cephalic vein, for long-term
intravenous access when the
client will be maintaining IV
therapy at home
Peripherally Inserted
Central Venous Catheter
(PICC)
Can be effective in restoring intravascular (blood)
volume
BLOOD TRANSFUSIONS
Four main groups/types of human blood:
A, AB, B, O
___ (Rh) Factor: Rh+ or Rh-
Rhesus
Blood should be typed and ____ first before
the transfusion
crossmatched
is the only IV solution that is
compatible with blood products
0.9% NaCl (Plain NSS)
Blood Products
Whole Blood
Packed RBC
Platelets
Fresh Frozen Plasma
Albumin and Plasma Protein Fraction
Packed Red Blood Cells (RBCs)
increase the oxygencarrying
capacity of blood in anemia, surgery and
blood disorders
not commonly used except for
extreme cases of acute hemorrhage; RBCs, plasma,
plasma proteins, fresh platelets, and other clotting
factors
Whole Blood
bleeding disorders or platelet deficiency
Platelets
expands blood volume and
provides clotting factors. No need to be typed and
crossmatched
Fresh Frozen Plasma (FFP)
blood volume
expander
Albumin and Plasma Protein Fraction
