objective 4 (1) Flashcards
what are the principles of fluid and electrolyte balance?
- Necessary for life and homeostasis
- Nursing role is to help prevent and treat fluid and electrolyte
disturbances
- State of equilibrium in body
- Naturally maintained by adaptive responses
- Body fluids and electrolytes are maintained within narrow limits
homeostasis
what is the % of water content of the body?
- 50% to 60% of body weight in adult
- 45% to 55% in older adults
- 70% to 80% in infants
inside the cell
intracellular fluid
outside a cell
extracellular fluid
Normal distribution of fluid in ICF and ECF
first spacing
Abnormal accumulation of interstitial fluid
second spacing
loss of ECF into a space that does not contribute to
equilibrium
third spacing
cations that carry a positive charge and anions
that carry a negative charge
active chemicals
what are the major cations?
sodium, potassium, calcium, magnesium and
hydrogen ions
what are the major anions>
chloride, bicarbonate, phosphate, sulfate and
proteinate ions
what is the major cation in ECF?
sodium (Na+)
what is the normal for sodium?
134-145 mmol/L
what is the major cation in ICF?
potassium K+
what does the movement of fluid through capillary walls depend on?
- Hydrostatic pressure
Pressure exerted on the walls of blood vessels - Osmotic pressure
Pressure exerted by the protein in the plasma
movement of water between 2 compartments
osmosis
movement of a substance from an area of higher concentration to
one lower concentration (ions and molecules - eg O2 and CO2)
diffusion
movement of water and solutes from high hydrostatic pressure to
low hydrostatic pressure (eg kidney filtering lymph)
filtration
energy is expended for the movement to occur against a
concentration gradient
12
active transport
what is the average fluid intake?
2500mL/day
what is the average fluid output?
1500mL/day Urine
100mL/day bowels
- Dietary intake of fluid and food or enteral feeding
- Parenteral fluids (IV)
fluid gain
- Kidney: urine output
- Lungs / skin loss - insensible losses
- GI tract
fluid loss
what are the homeostatic mechanisms?
- Kidney – regulates F & E balance
- Heart and Blood Vessel – renal perfusion and water and electrolyte
regulation - Lung – exhalation
- Pituitary – ADH conserves water as needed
- Adrenal – fluid retention or water loss
- Parathyroid –regulates calcium and phosphate balance
pinched skin with slow rebound
tenting
- loss of water alone with increased serum sodium
(Na+) level - Most common in older adults
dehydration
- low volume of extracellular fluid (blood )
- accompanied by low e- level
hypovolemia
what are the causes of hypovolemia?
- Prolonged vomiting, Diarrhea
- GI suctioning
- profuse urination or sweating
- decreased intake
- wound loss (burn injury)
- inability to gain access to fluid
what are the risk factors of hypovolemia?
diabetes insipidus, hemorrhage, coma, and
third space shifts
Greater due to decreased plasma
volume
hematocrit
hyponatremia and hypernatremia
sodium imbalances
hypokalemia and hyperkalemia
potassium imbalances
hypocalcemia and hypercalcemia
calcium imbalances
hypomagnesemia and hypermagnesemia
magnesium imbalance
hypophosphatemia and hyperphosphatemia
phosphorus imbalance
hypochloremia and hyperchloremia
chloride imbalances
what are the causes of hyponatremia?
adrenal insufficiency, water intoxication, SIADH, &
losses by vomiting, diarrhea, sweating, & diuretics
what are causes of hypernatremia?
excess water loss, excess Na+ administration, diabetes
insipidus, heat stroke, & hypertonic (3% NACL) IV
solutions
what is potassium for?
- Transmission and conduction of nerve and muscle
impulses - Cellular growth
- Maintenance of cardiac rhythms
- Acid–base balance* Transmission and conduction of nerve and muscle
impulses - Cellular growth
- Maintenance of cardiac rhythms
- Acid–base balance
what is the causes of hypokalemia?
- Abnormal losses of K+ via the kidneys or
gastrointestinal tract - Magnesium deficiency
- Metabolic alkalosis
what are the causes of hyperkalemia?
- Massive intake
- Impaired renal excretion
- Shift from ICF to ECF
- Most common in renal failure
- tissue trauma (severe burns)
what are the normal calcium values?
2.25-2.75 mmol/L
what are the causes of hypocalcemia?
- Decreased production of PTH (hypoparathyroidism)
- Acute pancreatitis
- Multiple blood transfusions
- Alkalosis
- Vitamin D deficiency
- Inflate a B/P cuff 20 mmHg above systolic
- Adducted thumb, flexed wrist and metacarpophalangeal joints, extended
interphalangeal joints
trousseau’s sign
Twitching of the facial muscles in response to tapping over the area of
the facial nerve.
chovstek’s sign
what are the causes of hypercalcemia?
- Hyperparathyroidism (two-thirds of cases)
- Malignancy
- Vitamin D overdose
- Prolonged immobilization
what the normal magnesium values?
0.74-1.07 mmol/L
what are the causes of hypomagnesemia?
- Prolonged fasting or starvation
- Chronic alcoholism
- Fluid loss from gastrointestinal tract
- Prolonged parenteral nutrition without supplementation
- Diuretics
what are the causes of hypermagnesemia?
Increased intake or ingestion of products containing
magnesium when renal insufficiency or failure is
present
what are the normal phosphorus values?
0.97-1.45 mmol/L
what are the causes of hypophosphatemia?
*Malnourishment/malabsorption
* Alcohol withdrawal
* Use of phosphate-binding antacids
* During parenteral nutrition with inadequate
replacement
what are the causes of hyperphosphatemia?
- Acute or chronic renal failure
- Chemotherapy
- Excessive ingestion of phosphate or vitamin D
what are the normal protein values?
64 – 83 g/l
what are the causes of hypoproteinemia?
Anorexia
- Malnutrition
- Starvation
- Fad dieting
- Poorly balanced vegetarian diets
Rare, but can occur with dehydration induced hemoconcentration
hyperproteinemia
