Fluid, Electrolyte, and acid-base balance Flashcards

pH
Terms Definitions
Alkalosis
pH > 7.45
Hypernatremia
sodium > 145 ---------------------------------------------------------------------------------------------------------- Primary manifestations are neurological ---------------------------------------------------------------------------------------------------------- Thirst mechanism protects against hyernatremia ---------------------------------------------------------------------------------------------------------- Clients at risk are unconscious, infants, elders with dementia, clients with impaired thirst mechanism
Disorders
Circulating buffers, respiratory performance, renal function
Primary cations in ICF
potassium, magnesium
common side effect of opiods
constipation
Sodium balance
aldosterone (from adrenal gland)
What electrolyte imbalance is associated with a loss of potassium?
Hypokalemia
sensible water loss
through excess perspiration
Non-electrolytes
substance that does NOT hold electrical charge
Overhydration
Water excess--occurs when excess water shifts into ICF : distorts cells, changes solute concentrations around enzymes and disrupts normal cell functions
intracellular fluids
Liquids within the cell membrane.
carbonic acid
dissociates in another reversible reaction (H2CO3-><-H+ +HCO3)
the breakdown of RBC's is called:
hemolysis
Dehydration
a condition in which fluid loss exceeds fluid intake and disrupts the body's normal electrolyte balance
When carbon dioxide concentrations rise, additional hydrogen ions are produced and the
pH goes down
Edema
The movement of abnormal amounts of water from plasma into interstitial fluid (swelling)
Aldosterone
Steroid hormone that is secreted by suprarenal cortex in response to rising K or falling Na levels in the blood or from the activation of renin-angiotensin system
Hypercapnia
the presence of an abnormally high level of carbon dioxide in the circulating blood (primary cuase is hypoventilation)
Acidosis
pH too low (high H+ ions)
-more common
transcellular fluid
Transcellular fluid is fluid separated from other fluids by a cellular barrier and consists of cerebrospinal, pleural, gastrointestinal, intraocular, peritoneal, and synovial fluids (Elgart, 2004). Loss of transcellular fluid can produce fluid and electrolyte disturbance.
produced
normally the amount of carbon dioxide exhaled equals the amount of carbon dioxide
What are the major anions?
chloride, bicarbonate, phosphate
Hematocrit
the proportion of red blood cells (erythrocytes) to the total blood volume
Solvent
the component of a solution that can dissolve a solute
What system controls all hormones and bodily functions?
nervous system
Electrolyte balance primarily involves balancing the rates of absorption across the digestive tract with rates of loss at the
kidneys and swear glands
vascular access devices
Catheters, cannulas, or infusion ports designed for long-term, repeated access to the vascular system.
sodium return increases
water follows salt increasing blood volume and pressure
Insensible water loss
continuous and not percieved by person
Arterial blood gas
test performed to evaluate the client's acid-base balance and oxygenation
Isotonic solution
has the same osmolality as body fluids ---------------------------------------------------------------------------------------------------------- example - normal saline, 0.9% sodium chloride
extracellular fluid
all the fluid outside the cell that includes interstitial, intravascular and transcellular fluid
Electrolyte Balance
When the gains and losses of all electrolytes is equal-- primarily involves balancing rates of absorption across the digestive tract with rates of loss at kidneys and sweat glands
Limitations of Buffer System
-provide only temporary solution to acid-base imbalance
-don't eliminate H+ ions
-supply of buffer molecules is limited
concentration gradient
water diffues into and out of cells, it is relatively small molecule and it is free to follow its _ _
What is the problem if the bicarb drops below 22?
Metabolic Acidosis
Ions
atoms or group of atoms that carry a positive or negative electric charge; electrolytes
An increases ADH causes what?
renal tubules retain WATER
- pure water gain or loss
- thus=vasoconstriction
Respiratory acid-base disorders result from..
Imbalance between Co2 generation in peripheral tissues and Co2 excretion at lungs (causes abnormal Co2 levels in ECF)
Describe dehydration
water leaves the cells & moves to the bloodstream
Fluids fail to return at the venous ends of capillary beds.
How does Edema occur?
Disorders that have the potential for disrupting pH balance in the body include
emphysema, renal failure, neural damage, CNS disease, heart failure, hypotension
Most important factor affecting pH in body tissues
Pco2 (they are inversely related)
What are the clinical manifestations of hypokalemia?
Muscle weakness, leg cramps, fatigue, lethargy, anorexia, N/V, decreased bowel sounds & motility, cardia dysrhythmias, depressed DTRs, weak/irregular pulses
What is the primary sign/cause of respiratory acidosis?
Low plasma pH due to hypercapnia
What is bicarbonate (HCO3) responsible for?
It a buffer to regulate acid-base balance
If water is gained but electrolyes are not...
ECF volume increases, ECF becomes hypotonic to ICF, fluid shifts from ECF to ICF---may result in overhydration (water excess)
What is the largest chemical buffer in ECF?
carbonic acid and bicarbonate buffer system; reacts to change in pH of ECF within seconds
If ICF volume is greater than ECF volume...
ICF acts as a water reserve and prevents large osmotic changes in ECF
Sodium (Na)
135-145 mEq/L ---------------------------------------------------------------------------------------------------------- most abundant cation in ECF and major contributor to serum osmolality ---------------------------------------------------------------------------------------------------------- controls and regulates water balance
Fluid Loss
-urinary system
-evaporation (respiratory, perspiration, and eyes)
*sensible: contains solutes, like in sweat glands
-feces (mucous membranes)
Hypophosphatemia
phosphate < 2.5 mg/dL ---------------------------------------------------------------------------------------------------------- glucose and insulin administation and TPN can cause phosphate to shift into the cells from ECF ---------------------------------------------------------------------------------------------------------- other possible causes - alcohol withdrawal, acid-base imbalances, use of antacids that bind with phosphate
meduim for transporting nutrients, waste, hormones, enzymes and blood
water
Potassium balance
aldosterone (from adrenal gland)
Solutes
substances dissolved in a liquid
what are interventions for caregiver role strain
...
Hyponatremia
Low Na concentration (body content rises --overhydration)
respiratory alkalosis
Abnormal condition characterized by decreased arterial carbon dioxide concentration and decreased hydrogen ion concentration.
hypokalemia
because loss of potasium increases with urine volume, diuretics can cause
Filtration
water and diffusable substances move together in response to fluid pressure, moving from an area of higher pressure to an area of lower pressure
Sources of potassium - beverages
milk, apricot nectar
Important homeostatic adjustments occur in response to changes in
plasma volume or osmolarity
Signs of overhydration
Abnormally low Na+ concentrations (hyponatremia), effects on CNS function (water intoxication)
Respiratory compensation
changes in respiratory rate to stabilize ECF pH
Blood buffers
• Prevent dramatic changes in hydrogen ion [H+]
• Act instantaneously
• Bind to H+ when pH drops
• Release H+ when pH rises
Health promotion activities in the area of fluid and electrolyte imbalances focuses primarily on:
client teaching
Sources of calcium
milk and milk products, canned salmon
Increased PTH causes what?
-increased blood calcium
-decreased blood phosphorus
Compensation for metabolic alkalosis involves
decreased pulmonary ventilation, increased loss of bicarbonates in the urine
Acute Phase
The initial phase; pH moves rapidly out of normal range
interstitial fluid
Fluid that fills the spaces between most of the cells of the body and that provides a substantial portion of the liquid environment of the body.
osmolality
is a way of expressing how many molecules of solute are present in a liter of solvent
TPN or total parenteral nutrition
nutritionally adequate hypertonic solution of glucose, electrolytes, and other nutrients given through an indwelling or central IV
Hyperchloremia
an excess of chloride in the blood plasma
Other electrolytes in ECF in smaller quantities
potassium, calcium, magnesium
infants have more water in their body and are more prone to what
FVD, dehydration
Examples of Cations and Anions in ECF
Sodium, Chloride, Bicarbonate
oncotic pressure
Total influence of a protein on the osmotic activity of plasma water.
interstitial fluids
which are the fluids between cells, s well as all other fluids in the body such as lymph and cerebrospinal fluid
What is the problem if the bicarb rises above 26?
Metabolic Alkalosis
Hydrostatic pressure
the pressure a liquid exerts on the sides of the container that holds it; also called filtration force
Extracellular fluids in the body consist of
interstitial fluid, blood plasma, lymph, cerebrospinal fluid, synovial fluid, serous fluids, aqueous humor, perilymph, endolymph
Strong acids and strong bases--
Dissociate completely in solution (ex. HCl, hydrochloric acid (stomach))
What can trauma, bleeding and burns lead to?
FVD (think cell destruction)
Intracellular fluid (ICF)
found within the cells of the body and accounts for about 2/3 of total body fluids, provides a medium in which metabolic processes of the cell take place
The force that tends to push water out of the plasma and into the interstitial fluid is the
net hydrostatic pressure
How do protein buffer systems respond to pH?
By accepting or releasing H+
__% of K+ in ECF. What's it's function?
2%; regulates metabolic activity
What do ion pumps reabsorb?
Na+ from filtrate in exchange for K+ from peritubular fluid
What happens to bicarb when the CO2 drops?
bicarb goes up (pH too)
If water is lost but electrolytes are regained...
ECF osmotic concentration rises, water moves ICF to ECF--- net change in ECF is small
If a pt lost 6.6 lbs how many ml of fluid were lost?
3,000 ml of fluid
What does carbonic acid do at the lungs?
It breaks down into carbon dioxide and water and the carbon dioxide diffuses into alveoli
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