Fluids, electrolytes, acid-base disorders Flashcards
Is water polar or nonpolar? What does it mean?
Water is polar; can dissolve charged or polar molecules
What role does water play?
Water is a transport for nutrients and waste products
What role do electrolytes play?
Conduct electricity, aid in regulation of fluid, acid-base balance, and are cofactors for enzymes (speed up reactions)
Why are babies more susceptible to fluid imbalance?
Lose more fluid through their skin, kidneys aren’t fully developed so there’s an increase in fluid loss
Why are older adults more susceptible to fluid imbalance?
Thin skin, decline in kidney function, aren’t as thirsty
What are some risk factors for fluid imbalance?
Kidney function (regulates fluid), overweight individuals (more fat=less water), being female
Where is most of our bodies water found?
Intracellular space (40% of body weight)
What is the most abundant cation in the intracellular fluid?
Potassium
What CAN pass through the capillary membrane? (more permeable; located between plasma fluid and interstitial fluid)
Water, glucose, sodium, potassium (electrolytes move freely here)
What CANT pass through the capillary membrane? (located between plasma fluid and interstitial fluid)
Albumin (blood protein) and RBC’s
What CAN pass through the plasma membrane? (located between the interstitial fluid and intracellular fluid)
Oxygen
What CANT move freely through the plasma membrane? (located between the interstitial fluid and intracellular fluid)
Glucose (needs channel), sodium, potassium (charged ions)
What three things control capillary hemodynamics?
Hydrostatic pressure, osmotic pressure, capillary permeability
What is hydrostatic pressure?
Pressure that the fluid exerts on walls of blood vessels; contributes to movement of water into interstitial space (ex: heart beats increase hydrostatic pressure)
What is osmotic pressure?
Pulls water back into capillary; drives reabsorption
What plays a big role in osmotic pressure?
Albumin, pulls water back in
What is capillary permeability?
What is allowed in and out of the cell
Example: if permeability was increased (inflammation) proteins and large particles are lost in interstitial fluid, causing a decrease in osmotic pressure, hydrostatic forces water out increasing the production of tissue fluid
If you lose fluid what happens to pressure?
It drops
Where is hydrostatic pressure the greatest?
Arterial end; favors moving out into interstitial space
Where does excess fluid go if it’s not reabsorbed into capillaries?
Lymphatic system to then be fed back to venous system
Where does most of the water get reclaimed in the capillary?
Venous end
True or false: under normal circumstances osmotic pressure should not change?
True
Clinical question: A person develops a blood clot in a deep vein of their left leg. The clot is blocking most of the veins diameter. How will capillary filtration pressure be affected?
There will be a compromised flow, hydrostatic pressure increases (moves water into interstitial space)
What is edema?
Abnormal infiltration of fluid; can be caused by decrease in albumin
What is transudate in regards for edema?
Clear fluid leaking out
What is exudate in terms of edema?
Proteins, WBC leaking out
What is pitting edema?
Too much fluid in interstitial space; gravity aids in this
How can you get edema?
Increased capillary pressure, decreased osmotic pressure, increased capillary permeability, lymphedema
How can an increase in capillary (hydrostatic) pressure contribute to edema?
Too much fluid leaks out
Examples: increased vascular volume (heart failure affects pump/flow; kidney disease holds onto too much water), venous obstruction (blood clot formation - thrombophlebitis), liver disease with portal vein obstruction (blockage or narrowing of portal vein leads to back pressure), acute pulmonary edema (excess fluid in lungs)
How can a decrease in osmotic pressure contribute to edema?
Increase loss of plasma proteins (protein-wasting kidney diseases, burns - fluid leaks from blood vessels and collects around damaged areas), decreased production of plasma proteins (liver disease, malnutrition - not enough protein = fluid leaking out bc proteins help to hold salt and water inside)
What is Kwashiorkor?
Extreme protein (albumin) malnutrition; fluid is suppressed bc of a lack of albumin
How does increased capillary permeability contribute to edema?
Increased capillary permeability allows capillaries to become very leaky
Examples: inflammation, allergic reactions, malignancy, tissue injury and burns
How does the obstruction of lymphatic flow (lymphedema) contribute to edema?
malignant obstruction of lymphatic structures, surgical removal of lymph nodes (compromises ability to remove fluids)
What is third spacing?
Problem with fluid distribution; fluids shift to areas where they don’t normally belong
Examples: pericardial sac, pleural space, peritoneal space
Cancer can cause third space shifts
What are ways someone can get a fluid imbalance?
Problems with intake (too much fluid)
Problems with output (too much fluid out)
Problems with distribution (not in right place)
What are some sources of fluid loss?
GI loss
Bleeding
Endocrine dysfunction (aldosterone and ADH)
Fever (increase in breathing=fluid loss)
Hyperventilation
Osmotic diuresis (increase urination)
Medication therapies
Recreational drugs (caffein, coffee=increase in urination)
Causes of fluid gain?
Over-hydration (too much fluid= hypervolemia)
Increased sodium intake (where sodium goes water follows)
Kidney disease
Liver disease
Heart failure
Endocrine disorders (Cushing’s disease - hyperaldosterone, SIADH)
Too much ADH = hold onto excess fluid
Where are baroreceptors found?
Carotid arteries and aortic arch
What are the components of arterial pressure?
Fluid volume (blood plasma)
Cardiac pump
Blood vessels
Give an example of how a change in one component of arterial pressure can lead to compensatory response in other components?
Ex: lose blood volume = heart beats faster, kidneys conserve fluid, vasoconstriction
What does hypovolemia and hypervolemia refer to?
How much plasma (volume of liquid) is in the blood vessels
Hypovolemia causes
Hypovolemia is when theres not enough plasma in blood vessels
Causes: fluid loss, diabetes, burns or wounds, sweating (diaphoresis), diarrhea, vomiting, hypothalamic lesions
Clinical manifestations of hypovolemia
Weight loss, hypotension, tachycardia, thirst, skin tenting, increased hematocrit, BUN, electrolytes, increased urine concentration, increased temperature w/o infection
Hypervolemia causes
Hypervolemia is when there’s too much plasma volume in blood vessels
Causes: fluid excess due to increased intake, renal failure, hyperaldosteronism (hold onto salt and water), steroid therapy
Hypervolemia clinical manifestations
Weight gain, hypertension (too much blood), bradycardia, edema, decreased hematocrit (ratio of RBC to fluid)
What does aldosterone do to BP and sodium?
Increases BP and holds onto sodium
Role of aldosterone
Helps control the balance of salt and water, regulation of blood pressure and blood volume
What is shock?
Decreased arterial flow and oxygenation of cells, tissues, and organs, usually due to marginal or markedly lowered blood pressure
4 broad types of shock
Hypovolemic (loss of volume)
Cardiogenic (pump failure)
Distributive (fluid in wrong place)
Obstructive (obstruction to flow)
What releases aldosterone?
Adrenal glands
Role of the Renin-angiotensin-aldosterone system
Regulates blood volume, blood pressure, fluid and electrolyte balance
Which organ metabolizes aldosterone?
Liver
Clinical relevance: severe liver disease can’t breakdown aldosterone therefore the person is at risk for hypervolemia (hold onto fluid) and weight gain
True or False? Sodium is more abundant outside the cell?
True; remember where sodium goes water follows, sodium can freely cross capillary membrane
What is diffusion?
movement of molecules from high concentration to low concentration; both solvent and solute move
What is osmosis?
movement of solvent (water) across a semipermeable membrane from high to low solvent concentration; only solvent moves
Isotonic?
same concentration as fluid in cell, no reason for water to move
Hypotonic?
Cell swells
Hypertonic?
Cell shrinks, pulls fluid out; very concentrated around RBC pulling fluid out
Atrial natriuretic peptide (ANP)
causes you to pee out sodium and therefore water too (where sodium goes, water follows)
What organs regulate sodium?
kidney and hypothalamus
Function of kidneys
monitors arterial pressure, retains sodium when arterial pressure decreases and eliminates when arterial pressure increases
What coordinates sodium function and the kidneys?
Sympathetic nervous system and renin-angiotensin-aldosterone system (RAAS)
How does the hypothalamus regulate sodium?
Via the anti-diuretic hormone (ADH); ONLY moves fluid; reclaims fluid from urine
What produces ADH? Why is it released?
Hypothalamus; released in response to osmolality (concentration)
What is the most common electrolyte imbalance?
Sodium
What is hyponatremia?
Too low of sodium concentration in blood; water will shift into cells
What is hypernatremia?
toomuchsodium concentration in blood; water will shift out of cells
Diabetes insipidus (DI)
low levels of ADH or inability for kidneys to respond to ADH
Causes: brain lesions, cranial surgery, or head injury, some medications, certain renal disorders
Syndrome of inappropriate ADH (SIADH)
Too much ADH
Common causes: cancer, pituitary tumor, neurologic infections (elevated levels of ADH), HIV infection
What may cause hyponatremia? Diabetes insipidus or SIADH?
SIADH (syndrome of inappropriate ADH); holding onto free water
Where do sodium imbalances manifest?
Nervous system
What is hyponatremia?
Low blood sodium levels; decrease in intake of sodium
Clinical application: Addison’s disease causes low aldosterone which then causes kidneys to hold onto water, decrease sodium reabsorption and excrete potassium, cellular swelling, chronic alcoholism, see slide 40
What is hypernatremia?
increase in blood sodium levels
Clinical application: Cushings syndrome causes increase in sodium and wastes potassium, increased thirst, see slide 40
What electrolyte is the heart more sensitive to and which is the brain more sensitive to?
Brain: sodium
Heart: potassium
What organ makes albumin?
Liver
What type of solution would you give to someone with cerebral edema?
Hypertonic solution
What is an iatrogenic injury?
Adverse mental or physical condition induced in a patient through the effects of treatment
Examples: rapid infusion of IV fluids can lead to heart failure and pulmonary edema
What organ plays a big role in the regulation of potassium?
Kidneys
Where is aldosterone produced and where is it metabolized?
Produced in adrenal glands, metabolized by liver
What is the role of aldosterone?
helps control the balance of water and salts in the kidney by keeping sodium in and releasing potassium from the body
How does liver disease cause hyperkalemia?
if the liver can’t metabolize aldosterone then potassium will accumulate
Where do symptoms appear in potassium balance?
Heart and muscle
What is hypokalemia?
decrease in potassium in the blood; caused by a decreased intake, vomiting, alkalosis, see slide 50
Clinical application: cardiac arrhythmia (low T wave)
What is hyperkalemia?
High levels of potassium in blood; caused by increased intake, renal failure (can’t get rid of potassium through kidneys), acidosis, see slide 50
Clinical application: Peaked T wave
Acidosis
High potassium, hyperkalemia; bicarbon is lost, high acid
Alkalosis
Low potassium, hypokalemia; increase in bicarb
What causes a peaked T wave?
Hyperkalemia
What can cause a transcellular shift?
trauma (cells damaged), acid-base disorders, catecholamine release (epinephrine drive potassium into cells), action of insulin (drive potassium into cells), medications
Addisons disease
adrenal insufficiency, abnormally low levels of adrenal hormones, don’t produce aldosterone (keeps sodium in, pee out potassium), can lead to hypovolemia, hyperkalemia, and acidosis
Cushing’s disease
excess aldosterone
What role does calcium play in the body?
muscle contraction, blood clotting, bone formation, enzyme function, heart rhythm
What acts on the kidneys and bone to remove calcium from the extracellular circulation?
calcitonin (tones calcium down)
What organs are responsible for the activation of vitamin D?
skin, kidneys, liver
What is the relationship between calcium and phosphorus?
inverse relationship; one goes up other goes down
Hypocalcemia
decrease in calcium in the blood; caused by decreased intake, vit D deficiency, liver disease, see slide 60
Clinical application: increased neuromuscular activity, muscle twitch
Hypercalcemia
increase of calcium levels in blood; caused by increased intake, immobility, bone malignancies, hyperparathyroidism, see slide 60
Clinical application: decreased neuromuscular activity, increased fracture risk
True or False: acids tend to donate protons and bases tend to accept protons
True
Definition of ph and Normal pH range
How many hydrogen ions in a solution
7.35-7.45
What happens to pH when theres more hydrogen? less?
More hydrogens = pH down
Less hydrogens = pH up
role of buffer systems
resist big changes in pH; absorb excess hydrogens or give up hydrogens
Normal PaCO2 range
35-45 mmHg
Normal HCO3 range
22-26 mEq/L
What metabolic exhaust is produced by aerobic metabolism?
Water, CO2
What metabolic exhaust is produced by anaerobic metabolism?
lactic acid
Low CO2 =
(Hint replace CO2 with acid)
Basic
High CO2 =
(Hint replace CO2 with acid)
Acidic
Low HCO3 =
(Hint replace HCO3 with base)
Acidic
High HCO3 =
(Hint replace HCO3 with base)
Basic
What does it mean to be uncompensated?
pH and 1 other value are outside of normal range
What does it mean to have partial compensation?
When all 3 values (pH, CO2, HCO3) are outside normal range
What does it mean to be fully compensated?
When pH is within normal range but CO2 and HCO3 are outside normal
If there’s a problem with CO2 does that indicate a respiratory or metabolic issue?
Respiratory
Acidosis leads to too many hydrogen ions or too little?
Too many
Alkalosis leads to too many hydrogen ions or too little?
Too little
