Fluids & Electrolytes, Acids & Bases Flashcards
Net Filtration
Forces favoring filtration - forces opposing filtration
Capillary hydrostatic pressure
blood pressure
-facilitates the outward movement of water from the capillary to the interstitial space
Capillary oncotic pressure
osmotically attracts water from the interstitial space back into the capillary.
Interstitial hydrostatic pressure
facilitates the inward movement of water from the interstitial space in to the capillary
Interstitial oncotic pressure
osmotically attracts water from the capillary into the interstitial space
Forces that favor filtration
-capillary hydrostatic pressure
-interstitial oncotic pressure
Forces that oppose filtration
-capillary oncotic pressure
-interstitial hydrostatic pressure
Causes of Edema
- venous or lymphatic obstruction
- increased vascular volume (increased hydrostatic pressure)
- plasma protein loss
- increased capillary membrane permeability (decreased plasma oncotic pressure)
Effusion
Fluid accumulation in a body cavity or space (aka third space)
Difference between interstitial fluid, extra cellular fluid and transcellular fluid
Interstitial fluid: fluid surrounding the cells and found in the spaces between cells but not within blood vessels
Extracellular fluid: fluid outside the cells including interstitial, intravascular and transcellular fluids.
Transcellular: fluids contained in epithelial-lined cavities (pleural, synovial, peritoneal, pericardial, intraocular, gastric juice, saliva, bile, pancreatic juice, ileal fluid, cecal fluid, CSF and sweat)
What is the difference between a volatile and non volatile acid
Volatile: can be eliminated as CO2 gas
Nonvolatile: can only be eliminated by the kidney
Difference between acidemia and acidosis
Acidemia: state in which the pH of arterial blood is less than 7.35
Acidosis: systemic increase in H+ concentration or a loss of base
What regulates sodium?
Aldosterone which is controlled by
renin and angiotensin enzymes
Osmolarity vs Osmolality
Osmolarity: number of osmoles of solute per L of solution
Osmolality: number of osmoles of solute per KG of solution
Causes of hyperchloremia
Hypernatremia & elevated bicarbonate concentrations
What is the predominant EXTRA cellular fluid electrolyte
Sodium
What is the predominant INTRA cellular fluid electrolyte
Potassium
What are the 5 essential functions of calcium
- bone structure
- blood clotting
- hormone secretion
- function of cell receptors
- membrane stability
Phosphate
-buffer in acid-base balance
-energy for muscle contraction
HYPOcalcemia
Value & causes
<9.0mg/dL
Causes:
1. inadequate absorption
2. deposition into bone or soft tissue
3. blood administration
4. decreased PTH and Vit D
HYPERcalcemia
Value & causes
> 10.5mg/dL
causes:
1. hyperparathyroidism
2. bone metastases
3. sarcoidosis
4. excess vit D
HYPOphosphatemia
Value & Causes
<2.0mg/dL
causes:
1. intestinal malabsorption
2. increased renal excretion
HYPERrphosphatemia
Value & Causes
> 4.7mg/dL
Causes:
acute or chronic renal failure with loss of GF
HYPOmagnesmia
Value & Causes
<1.5mEq/L
Causes: malabsorption
HYPERmagnesmia
> 3.0 mEq/L
causes: renal failure (still rare)
What are the primary plasma pH buffers
- bicarbonate
- phosphate
- protein (Hb)
What is the sole volatile acid
carbonic acid
What are the nonvolatile acids (5)
- Lactic acid
- phosphoric acid
- sulfuric acid
- acetoacetic acid
- beta-hydroxybutyric acid
Aquaporins
Family of water channel proteins that provide water permeability
Hypovolemic HYPERnatremia
What it is and causes
It is: loss of Na is accompanied by a relatively greater loss of body water.
Causes: look diuretics, diuretic stages or renal disease, osmotic diuresis from DM hyperglycemia or mannitol.
Isovolemic HYPERnatremia
Loss of electrolyte free water with a near normal sodium concentration.
causes: inadequate H2O intake, excessive sweating, fever with hyperventilation, increased water loss from lungs, burns, vomiting, diarrhea and DI (central or nephrogenic)
HYPERvolemic HYPERnatremia
increase in TBW with a greater increase in total body Na –> hypervolemia with high Na.
causes: hypertonic saline, over secretion of ACTH or aldosterone, or deliberate over consumption (salt water or soy sauce)
HYPERnatremia
Clinical symptoms, evaluation and treatment
Sx: Weakness, lethargy, hyperreflexia, muscle twitching, confusion, coma and seizures
Eval: lab tests, H&P. serum Na >145 & urine specific gravity > 1.030, Hct & plasma protein will be elevated if water loss
Treatment: isovolemic and hypovolemic hypernatremia is H2O PO or D5 SLOW!
Hypervolemic hypernatremia is loop diuretics. (frequent Na checks)
Isovolemic HYPOnatremia
loss of Na without significant loss of water
Causes: water retention SAIDH, hypothyroidism, PNA, glucocorticoid deficiency.
Dilutional hypotonic hyponatremia (water intoxication)
Causes
intake of large amounts of electrolyte free water or replacement of fluid loss with D5, tap water enemas, aspiration of fresh water in nonfatal drowning, SSRIs and SAIDH.
HYPERvolemic HYPOnatremia
Definition and causes
total body Na is increased AND there is excess water –> increase in ECF decreasing serum Na.
causes: heart failure, cirrhosis, nephrotic syndrome.
HYPERtonic HYPOnatremia
Definition and causes
Shift of water from the ICF to the ECF. Osmotic fluid shift to the ECF dilutes the concentration of Na and other electrolytes
Causes: hyperglycemia, hyperlipidemia, and hyperproteinemia.
Hyperchloremia
Value and causes
<97mEq/L
causes: with hyponatremia, elevated bicarbonate, metabolic alkalosis, restricted NaCl intake, diuretics, vomiting, Cystic fibrosis.
Potassium adaptation
ability of the body to adapt to increased levels of K+, sudden increases can be fatal but slow intake
Familial hypokalemic periodic paralysis
Rare genetically transmitted disease that causes potassium to shift into the intracellular space with episodes of extreme muscle weakness.
