Fluids and Electrolytes / GI Flashcards
(140 cards)
Capillary hydrostatic pressure
facilitates the outward movement of water from the capillary to the interstitial space
-pushes
Capillary (plasma) oncotic pressure
osmotically attracts water from the interstitial space back into the capillary
-pulls
interstitial hydrostatic pressure
facilitates the inward movement of water from the interstitial space into the capillary
interstitial oncotic pressure
osmotically attracts water from the capillary into the interstitial space
Edema
excessive accumulation of fluid within the interstitial spaces
Increase in Capillary Hydrostatic Pressure
Edema
- hydrostatic pressure increases as a result of venous obstruction or salt and water retention
- venous obstruction causes hydrostatic pressure to increase behind the obstruction, pushing fluid from the capillaries into the interstitial spaces
Decrease in Capillary Oncotic Pressure
Edema
-the decreased oncotic attraction of fluid w/in the capillary causes filtered capillary fluid to remain in the interstitial space
Increase in Capillary Permeability
Either pores are enlarged or capillary wall is damaged and fluids and proteins leak out because normal barrier is not there
Lymphatic obstruction (lymphedema)
when lymphatic channels are blocked=proteins and fluid accumulate in interstitial space=lymphedema
Clinical Manifestations of Edema
Localized: site of cut/ trauma
Generalized: swelling of ankles
Pitting: scale of 0-5, 4= pitting
Water deficit: dehydration
water deficit, but also used to indicate both sodium and water loss (isotonic or iso osmolar dehydration)
Pure water deficit
(hyperosmolar or hypertonic dehydration) rare, because most ppl have access to water
Most common cause of water deficit
increased renal clearance of free water: result of impaired tubular function or inability to concentrate urine
Clinical Manifestations: Water deficit
- headache, thirst, dry skin and mucous membranes, elevated temp., weight loss, decreased or concentrated urine
- skin turgor may be normal or decreased
- hypovolemia: tachycardia, weak pulses, postural hypotension
Water Excess
-Water intoxication: compulsive water drinking
renal failure, severe congestive heart failure, cirrhosis
-Overall effect of dilution of the ECF, with water moving to the intercellular space by osmosis
Clinical Manifestations: Water excess
weakness, nausea, muscle twitching, headache and weight gain
Hyponatremia
serum sodium concentration falls below 135 mEq/L
-loss of sodium, inadequate intake of sodium or dilution of sodium by water excess
Dilutional hyponatremia
occurs when there is a replacement of fluid loss with intravenous 5% dextrose in water
Clinical Manifestations: hyponatremia
- decrease in sodium concentration changes the cell’s ability to depolarize and repolarize normally, altering the action potential in neurons and muscles
- neurological changes: lethargy, confusion, apprehension, depressed reflexes, seizures and coma
- muscle twitching and weakness are also common
- cerebral edema can be life-threatening complication of hypervolemic hyponatremia
Hypernatremia
serum sodium >145 mEq/L
-Related to sodium gain or water loss
Manifestations: Hypernatremia
Hyperactive reflexes
Neurological confusion
Coma
Convulsions
Hyperkalemia
evaluation of ECF [K] 5.5 mEq/L
Causes of Hyperkalemia
-Increased intake
-Supplements such as K salts, use of stored whole blood and intravenous boluses of K penicillin G, or replacement K
K going from ICF → ECF
-Cell trauma (such as burns, massive crush injuries, or extensive surgeries), changes in cell membrane permeability. acidosis, insulin deficiency, cell hypoxia
-Decreased Renal Excretion
renal failure that results in oliguria (
Clinical Manifestations for hyperkalemia
-Mild Attacks:increased neuromuscular irritability
-restlessness, intestinal cramping, and diarrhea
-Severe Attacks: muscle weakness, loss of muscle tone, paralysis
-May cause bradydysrhythmias and delayed conduction
ventricular fibrillation and cardiac arrest
-Causes decreased cardiac conduction and more rapid repolarization of heart muscle