Week 1: Fluid and Electrolyte Balance I Flashcards
Fluid Compartment: Intracellular
- fluid within the cells
- 2/3 of body fluid (primarily in muscle mass)
Fluid Compartment: Extracellular
Fluid outside the cells
1/3 of body fluid
Transports electrolytes, enzymes and hormones
intravascular
Fluid within the blood vessels
Contains plasma (half of total blood volume)
Interstitial
Contains fluid that surrounds the cell
11-12 L in adults
Lymph fluid
Transcellular
Smallest space
1L in adults
Cerebrospinal, pericardial, synovial, intraocular, pleural fluids, sweat, digestive secretions
Third Spacing
loss of ECF into a space that does not contribute to equilibrium
What are the signs and symptoms of Third Spacing?
decreased urine output (despite adequate intake), increased heart rate, decreased blood pressure, decreased central venous pressure, edema, increased body weight, imbalanced intake and output (I&O)
Symptoms can look as if the patient is retaining fluid but are presenting as dehydrated
Caused by: intestinal obstruction, pancreatitis, crushing traumatic injuries, bleeding, peritonitis, major venous obstruction
Cations
sodium, potassium, calcium, magnesium, hydrogen ions
Anions
chloride, bicarbonate, phosphate, sulphate, proteinate ion
Osmosis
movement of water across selectively permeable membrane from an area of HIGH concentration, to area of LOW concentration; based on osmolality
Diffusion
movement of particles across semi-permeable membrane from area of HIGH concentration, to area of LOW concentration
Filtration
movement of fluid through a cell or vessel membrane due to hydrostatic pressure differences
Hydrostatic pressure: pressing of water molecules outwards from a confined space, forces water to move from area of HIGH pressure to area of LOW pressure
Renin-Angiotensin-Aldosterone System (RAAS)
Decrease in perfusion to kidneys = renin release
Renin converts angiotensinogen to angiotensin I in blood
Angiotensin I converted to angiotensin II in lungs
Angiotensin II = vasoconstriction, stimulate thirst, stimulate aldosterone to retain water and Na
Atrial Natriuretic Peptide (ANP) inhibits this system when in state of overload
Hypovolemia
Occurs when loss of ECF volume exceeds the intake of fluid.
decrease in fluid in body
due to: insufficient intake, excessive loss or fluid shifts in body (third spacing)
fluid deficit in intravascular space = difficulty perfusing body, systems activate to raise BP
S&S of Hypovolemia
decreased weight
decreased skin turgor
weak, rapid pulse
low BP
thirst
Confusion
Causes of hypovolemia
vomiting, diarrhea, GI suctioning, sweating, nausea, third spacing shifts
Hypervolemia
retention of fluid in the body (retention of sodium)
due to: excessive intake, abnormal retention (kidney/heart)
fluid overload in intravascular space = raise BP, stress on systems
Hypervolemia causes
heart failure
kidney injury
cirrhosis of the liver
excessive consumption of sodium
S&S of hypervolemia
edema
distended neck veins
dyspnea
cough
Shortness of breath (SOB)
crackles
Fluid Volume Deficit: Nursing Management
- Correct the underlying cause of the deficit (eg. vomiting)
- Replace fluids and electrolytes (oral + IV rehydration)
- Prevent and assess inadequate perfusion
- Signs of improvement:
Stable blood pressure and heart rate
Expected skin turgor
Client moves towards other expected findings
Fluid Volume Overload: Nursing Management
- Correct underlying cause of deficit (eg. heart failure, kidneys)
- Limit sodium/fluid intake
- Administer diuretics
- Signs of improvement:
Daily weight checks
Stable blood pressure
Crackles in lung sounds
Pharmacological interventions for Fluid volume overload
Furosemide (Lasix)
Loop diuretic
Increases renal excretion, mobilizes fluid, decreases BP
Side effects – dizziness, headache, hypotension, electrolyte imbalance
Nursing considerations:
Fall risk
Electrolyte imbalance
Pre-existing kidney function + impact on kidneys