Fluid and Electrolytes Flashcards
Hypernatremia
145 mEq/L=mmol/L or greater
2/3 Fluid
ICF
1/3 Fluid
ECF
1 L of water=
=2.2 lbs of water
Electrolytes in ECF
Na+
Cl-
Ca+
HCO3-
Electrolytes in ICF
K+, PO4-, Mg+
Na:K::Ca:??
PO4 (Phosphorus)
Solutes move
Diffusion
Carrier Molecule
Facilitated Diffusion
Requires protein (ATP) to transport
Active Transport
Normal plasma osmolality
275-295 mOsm/kg
Water excess osmolality
< 275 mOsm/kg
Dilute
Water deficit osmolality
> 295 mOsm/kg
Dehydrated
Measures the weight of a substance compared with an equal part of water
Urine specific gravity
Normal urine specific gravity
1.010-1.020
Urine specific gravity in mOsm/kg
300 mOsm/kg
Solution when no net water movement occurs; ICF and ECF net no movement.
Isotonic solution
Water moves out of the cells causing cells to shrink or possibly die.
Hypertonic
Water moves into the cell, causing the cells to swell or burst due to osmosis
Hypotonic
Examples of Isotonic Fluids
- Normal Saline - 0.9% Sodium Chloride
2. Lactated Ringers (LR)
Examples of Hypotonic Fluids
- 1/2NS - 0.45% Sodium Chloride
2. D5W?
Examples of Hypertonic Fluids
- Dextrose 5% in 1/2NS
- Dextrose 5% in NS
- Dextrose 5% in LR
is the osmotic pressure caused by plasma colloids in solution
oncotic pressure
is the osmotic pressure caused by plasma colloids in solution
oncotic pressure
Describe the abnormal fluid shift: elevation of venous hydrostatic pressure
Increasing the pressure at the venous end of the capillary inhibits fluid movement back into the capillary, which results in edema.
Caused by: fluid overload, heart failure, liver failure, obstruction of venous return to the heart and venous insufficiency.
Describe the abnormal fluid shift: Decrease in Plasma Oncotic Pressure
Fluid remains in the interstitial space if the plasma oncotic pressure is too low to draw fluid back into the capillary. Low plasma protein content decreases oncotic pressure. This can result from excessive protein loss, deficient protein synthesis, and deficient protein intake.
Describe the abnormal fluid shift: Elevation of Interstitial Oncotic Pressure
Trauma, burns, and inflammation can damage capillary walls and allow plasma proteins to accumulate in the interstitial space. This increases interstitial oncotic pressure, draws fluid into the interstitial space, and holds it there.
A term used to describe the distribution of body water.
Fluid spacing
Describes the normal distribution of fluid in ICF and ECF compartments.
First spacing
occurs when fluid accumulates in a portion of the body from which it is not easily exchanged with the rest of the ECF; it’s trapped and unavailable for functional use
EX: Ascites, sequestration, fluid in abdominal cavity, edema associated with burns, trauma, or sepsis.
Third spacing
occurs when fluid accumulates in a portion of the body from which it is not easily exchanged with the rest of the ECF; it’s trapped and unavailable for functional use
EX: Ascites, sequestration, fluid in abdominal cavity, edema associated with burns, trauma, or sepsis.
Third spacing
Hormone for sodium retention and K excretion; from adrenal cortex
Aldosterone
Hormone from Hypothalmus/Pituitary that tells kidneys to reabsorb water
Anti-diuretic hormone
Hormone that acts on/from kidneys that stimulates release of aldosterone
Renin
Hormones made by the heart and suppress secretion of aldosterone, and ADH. Promote excretion of Sodium and water, resulting in decrease in blood volume and blood pressure.
ANP and BNP
Normal water intake and ouput
2000-3000mL
Describe osmotic diuretics
-Mannitol/Resectisol Osmitrol
Used to decrease brain cell swelling and used in acute renal failure (since hanging on to fluids)
Describe Loop Diuretics
Examples: Lasix/Furosemide
Very effective. You’ll lose K (Digoxin Toxicity).
Describe Thiazide Diuretics
- hydrochlorothiazide (HydroDiuril)
- Taken PO, not IV
- Cheap, usually for HTN
- Reduces BP
Describe Potassium Sparing diuretics
Spironolactone/Aldactone
-Used in edema, HTN, Ascites, HF, Instruct to limit foods high in K
Describe Potassium Sparing diuretics
Spironolactone/Aldactone
-Used in edema, HTN, Ascites, HF, Instruct to limit foods high in K
Describe gerontological considerations with fluids.
- Decreased Rennin and aldosterone
- Increased ADH and ANP
- Increased loss of moisture through the skin
- Thirst center is less effective
Children and Elderly susceptible to fluid and electrolyte imbalances… why?
- Inability to obtain fluid without help
- Inability to express feelings of thirst
- Inaccurate assessment of output (diapers)
- loss of fluid through perspiration (fever)
- Loss of fluid through diarrhea and vomiting
Define dehydration
- Serum osmolality and sodium concentration increasees
- refers to loss of pure water alone without loss of Na
Causes of Dehydration
- Decreased intake of H2O
- Osmotic diuresis ( uncontrolled DM)
- Diabetes Insipidus (lowers ADH)
- Over-use of diuretics
dehydration - what to look for?
- Tachycardia
- Hypotension
- Changes in mental status (ALOC)
- Seizures
- Coma
- Dizziness
- Weakness
- Wt loss
- Extreme thirst
- Fever
- Dry skin and mucous membranes
- Poor turgor (tenting)
- Urine output decreased
- Concentrated urine
Dehydration Lab Values
- Elevated Hematocrit (HCT)
- Elevated serum osmolality (above 300 mOsm/kg)
- Elevated serum sodium level (above 145 mEq/L)
- Urine specific gravity above 1.030
Dehydration Lab Values
- Elevated Hematocrit (HCT)
- Elevated serum osmolality (above 300 mOsm/kg)
- Elevated serum sodium level (above 145 mEq/L)
- Urine specific gravity above 1.030
How to treat dehydration?
REPLACE FLUIDS
Causes of hypovolemia
- GI Losses (NV, diarrhea, suction, fistula drainage)
- Hemorrhage
- Third Spacing
Hypovolemia: What to look for when blood loss is minimal? (25%)
- Increasing confusion, restlessness and anxiety to unconsciousness
- Weak to absent peripheral pulses
- Flat jugular veins
- Dizziness
- Nausea
- Extreme thirst
- Urine output <10ml
Hypovolemia: What to look for when blood loss is minimal? (25%)
- Increasing confusion, restlessness and anxiety to unconsciousness
- Weak to absent peripheral pulses
- Flat jugular veins
- Dizziness
- Nausea
- Extreme thirst
- Urine output <10ml
Hypovolemia: What to look for when blood loss is minimal? (40% or more)
Hypovolemic SHOCK occurs
- Hypotension
- Tachycardia
- Weak or absent peripheral
- Cool, mottled skin
- Cyanosis
Hypovolemia: Lab Values
- Normal or high sodium values (>145)
- Decreased Hgb and HCT levels (due to blood loss)
- Elevated BUN and Creatinine
- Increased urine specific gravity
- Increased serum osmolality