Module 8 - Fluid and Electrolyte Balance Flashcards
Substances that dissociate in solution to form a charged particle
Electrolytes
Sodium
135-145 mEq/L
Potassium
3.5-5.0 mEq/L
Chloride
98-106 mEq/L
Bicarbonate
24-31 mEq/L
Calcium
8.5-10.5 mg/dL
Magnesium
- 3-2.1 mg/dL
1. 8-3.0?
Pushing force exerted by a fluid. Arterial capillary pressure is about 30 mmHg and venous is 10 mmHg
Hydrostatic pressure
Pulling force of plasma proteins that cannot pass through the capillary membranes; assist the movement of fluid back into the capillary
Colloid osmotic pressure
Fluid trapped in one of several possible transcellular spaces
-This fluid is not available for ECF or ICF uses, since it is trapped or “sequestered”
Ex. Pleural effusion, pericardial effusion, ascites
“Third Spacing”
Movement of water from an area of lower concentration to an area of greater concentration of solutes (electrolytes)
Osmosis
Obligatory urine output
300-500 ml/24 hrs
A disorder causing loss of ability to sense thirst
Hypodipsia
“Dehydration”
Fluid volume deficit
equal loss of water and sodium (common cases: vomiting, diarrhea, misuse of diuretics)
Isotonic fluid volume deficit
More water loss than sodium. (osmotic diuresis, excessive sweating, loss of thirst sensation, unable to obtain or drink fluids)
Hypertonic fluid volume deficit
more sodium is lost than water. Serum Na+ is low
excess renal losses of Na+, aldosterone deficieny
Hypotonic fluid volume deficit
Fluid volume deficit symptoms
- Dry skin and mucous membranes
- decreased urine output
- in babies, depressed fontanel (soft spot on top of head)
- B.P may be decreased with heart rate increased
Physiological consequences of severe fluid volume deficit
Inadequate kidney perfusion - can result in acute renal failure
Steps:
- RECOGNITION
- Treatment with IV fluids or blood
Fluid volume EXCESS causes:
- impaired kidney function - decreased urine output
- heart failure or cardiac insufficiency
- excessive intake of water and sodium
- fluid retention related to stress response
Fluid volume EXCESS s/s
- acute weight gain
- increased bp r/t increased vascular volume
- strong bounding pulse
- possible dyspnea
- possible jugular venous distention (JVD)
- edema
_________ a blood test that shows the % or proportion of RBCs to the plasma (fluid)
Hematocrit
40-50% m
37-47% f
_______ a lab test that measures the density of urine, compared to the density of water
Urine Specific Gravity
1.010-1.025
Reflects the kidney’s ability to produce a concentrated or dilute urine based on serum osmolality and the need for water conservation or excretion
Urine Osmolality
Drugs to decrease fluid volume: Diuretics
- Furosemide (Lasix)
- Hydrochorothiazide (HCTZ)
- Spironlactone (aldactone)
Mechanism of Action - acts in the ascending loop of Henle to block sodium and chloride reabsorption, causing profound diuresis
Lasix (furesomide)
Mechanism of Action - blocks reabsorption of sodium and chloride in distal convoluted tubule; produces much less loss of urine than lasix and adequate urine function must be present
Thiazide diuretic (Hydrochlorothiazide)
Mechanism of action: blocks the actions of aldosterone in the distal nephron, promotes sodium uptake in exchange for potassium secretion. not as much diuresis as thiazides
Spironolactone (aldactone)
useful for blocking loss of potassium when pt also on lasix
a sign of excess interstitial fluid
Edema
potential etiologies of edema
- Increased hydrostatic pressure
- lowered plasma oncotic pressure (decrease in plasma proteins - albumin)
- Increased capillary permeability
- Lymphatic channel obstruction
