Fluid and Electrolytes Chapter 11
objectives -
-protect the patient with a change in fluid and electrolyte balance issue
- teach people how to prevent, recognize, and manage a change in fl and electrolyte balance
-reduce psychological impact for the patient experiencing a change in fluids.
homeostasis -
-state of equilibrium in body
-naturally maintained by adaptive responses
-body fluids and electrolytes are maintained within narrow limits
water content of the body -
50-60% in adults
45-55% in older adults
70-80% in infants
-varies with gender, body mass, and age
compartments -
-intracellular fluid (ICF) is 2/3 of body fluid
-extracellular fluid (ECF) is 1/3 of body fluid
-intravascular plasma (1/3 of ECF)
-interstital (2/3 of ECF)
-trancellular (not really talked about)
fluid compartments of the body -
intracellular
extracellular (intravascular (inside vessels) and interstital)
mechanisms controlling fluid and electrolyte movement -
-filtration
-diffusion/facilitated diffusion
-osmosis
diffusion -
movement of molecules from an area of higher concentration to an area of lower
concentration
osmosis -
osmosis allows the movement of water when there is a nonpearmable membrane
present that cant go through the membrane. with osmosis you are diluting the stronger
concentration.
filtration: clinical significance is blood pressure -
Blood pressure is an example of hydrostatic filtering forces. It moves whole blood
from the heart to capillaries where filtration can occur to exchange water, nutrients, and waste
products between the blood and the tissues.
1|Page
,clinical significance: edema -
edema develops with changes in normal hydrostatic pressure differences
effects of water status on RBC -
hypotonic (water into rbc)
hypertonic (water leaving the rbc)
isotonic (neutral)
fluid balance with intake and loss -
fluid loss: minimum amount of urine needed to excrete toxic waste products is
400-600mL if less than this notify hcp
-insensible water loss
regulation of water balance -
insensible water loss
-invisible vaporization from lungs and skin
-loss of approximately 600-900mL day
-no electrolyte loss
fluid spacing -
first spacing: normal distribution of fluid in ICF and ECF
second spacing: abnormal accumulation of interstitial fluid (edema)
third spacing: fluid accumulation in body where it is not easily exchanged with ECF
hormonal regulation of fluid balance -
aldosterone
antidiuretic hormone (ADH)
natriuretic peptides (NP)
regulation of water balance: hypothalamic-pituitary regulation -
hypothalamic-pituitary regulation
-osmoreceptors in hypothalamus sense fluid deficit or increase
-deficit stimulates thirst and antidiuretic hormone (ADH)
-decreased plasma osmolality (water excess) suppresses ADH release
regulation of water balance: renal regulation -
primary organs for regulating fluid and electrolyte balance
-adjusting urine volume
-selective re absorption of water and electrolytes
-renal tubules are sites of action of ADH and aldosterone
regulation of water balance: adrenal cortical regulation -
releases hormones to regulate water and electrolytes
-glucocorticoids (cortisol)
-mineralcorticoids (aldosterone)
regulation of water balance: GI regulation -
oral intake accounts for most water
-small amounts of water are eliminated by GI tract in feces
-d/v can lead to significant fluid and electrolyte loss
2|Page
, gerontological considerations -
-structural changes in kidneys decrease ability to conserve water
-hormonal changes lead to decrease in renin and aldosterone and increase ADH and ANP
-loss of subcutaneous tissue leads to increased loss of moisture
geri considerations continued -
-reduced thirst mechanism results in decreased fl intake
-functional changes affect ability to independently obtain fluids
-nurse must assess for these changes and implement treatment accordingly
fluid and electrolyte imbalances -
-directly caused by illness or disease (burns of HF)
-result of therapeutic measures ( IV fluid replacement or diuretics)
extracellular fluid volume imbalance (hypovolemia) -
ECF volume deficit (hypovolemia)
-abnormal loss of normal body fluids, inadequate intake, or plasma to interstitial fluid shift
-clinical manifestations r/t loss of vascular volume as well as CNS effects
treatment: replace water and electrolytes with balanced IV solutions
extracellular fluid volume imbalance (hypervolemia) -
fluid volume excess
-excessive intake of fluids, abnormal retention of fluids, or interstitial to plasma fluid shift
-clinical manifestations r/t excess volume
treatment: remove fluid without causing change in electrolyte composition or osmolarity of
ECF
electrolytes -
sodium: hyponatremia / hypernatremia
potassium: hypokalemia/hyperkalemia
calcium: hypocalcemia/hypercalcemia
magnesium: hypomagnesemia/hypermagnesemia
phosphorus: hypophosphatemia/hyperphosphatemia
chloride: hypochloremia/hyperchloremia
sodium -
imbalances typically associated with parallel changes in osmolality
-plays a major role in:
ECF volume and concentration
generation/transmission of nerve impulses
muscle contractility
acid-base balance
hypernatremia -
elevated serum sodium occurring with water loss or sodium gain
-causes hyperosmolality leading to cellular dehydration
primary protection is thirst from hypothalamus
hypernatremia manifestations: -
3|Page
objectives -
-protect the patient with a change in fluid and electrolyte balance issue
- teach people how to prevent, recognize, and manage a change in fl and electrolyte balance
-reduce psychological impact for the patient experiencing a change in fluids.
homeostasis -
-state of equilibrium in body
-naturally maintained by adaptive responses
-body fluids and electrolytes are maintained within narrow limits
water content of the body -
50-60% in adults
45-55% in older adults
70-80% in infants
-varies with gender, body mass, and age
compartments -
-intracellular fluid (ICF) is 2/3 of body fluid
-extracellular fluid (ECF) is 1/3 of body fluid
-intravascular plasma (1/3 of ECF)
-interstital (2/3 of ECF)
-trancellular (not really talked about)
fluid compartments of the body -
intracellular
extracellular (intravascular (inside vessels) and interstital)
mechanisms controlling fluid and electrolyte movement -
-filtration
-diffusion/facilitated diffusion
-osmosis
diffusion -
movement of molecules from an area of higher concentration to an area of lower
concentration
osmosis -
osmosis allows the movement of water when there is a nonpearmable membrane
present that cant go through the membrane. with osmosis you are diluting the stronger
concentration.
filtration: clinical significance is blood pressure -
Blood pressure is an example of hydrostatic filtering forces. It moves whole blood
from the heart to capillaries where filtration can occur to exchange water, nutrients, and waste
products between the blood and the tissues.
1|Page
,clinical significance: edema -
edema develops with changes in normal hydrostatic pressure differences
effects of water status on RBC -
hypotonic (water into rbc)
hypertonic (water leaving the rbc)
isotonic (neutral)
fluid balance with intake and loss -
fluid loss: minimum amount of urine needed to excrete toxic waste products is
400-600mL if less than this notify hcp
-insensible water loss
regulation of water balance -
insensible water loss
-invisible vaporization from lungs and skin
-loss of approximately 600-900mL day
-no electrolyte loss
fluid spacing -
first spacing: normal distribution of fluid in ICF and ECF
second spacing: abnormal accumulation of interstitial fluid (edema)
third spacing: fluid accumulation in body where it is not easily exchanged with ECF
hormonal regulation of fluid balance -
aldosterone
antidiuretic hormone (ADH)
natriuretic peptides (NP)
regulation of water balance: hypothalamic-pituitary regulation -
hypothalamic-pituitary regulation
-osmoreceptors in hypothalamus sense fluid deficit or increase
-deficit stimulates thirst and antidiuretic hormone (ADH)
-decreased plasma osmolality (water excess) suppresses ADH release
regulation of water balance: renal regulation -
primary organs for regulating fluid and electrolyte balance
-adjusting urine volume
-selective re absorption of water and electrolytes
-renal tubules are sites of action of ADH and aldosterone
regulation of water balance: adrenal cortical regulation -
releases hormones to regulate water and electrolytes
-glucocorticoids (cortisol)
-mineralcorticoids (aldosterone)
regulation of water balance: GI regulation -
oral intake accounts for most water
-small amounts of water are eliminated by GI tract in feces
-d/v can lead to significant fluid and electrolyte loss
2|Page
, gerontological considerations -
-structural changes in kidneys decrease ability to conserve water
-hormonal changes lead to decrease in renin and aldosterone and increase ADH and ANP
-loss of subcutaneous tissue leads to increased loss of moisture
geri considerations continued -
-reduced thirst mechanism results in decreased fl intake
-functional changes affect ability to independently obtain fluids
-nurse must assess for these changes and implement treatment accordingly
fluid and electrolyte imbalances -
-directly caused by illness or disease (burns of HF)
-result of therapeutic measures ( IV fluid replacement or diuretics)
extracellular fluid volume imbalance (hypovolemia) -
ECF volume deficit (hypovolemia)
-abnormal loss of normal body fluids, inadequate intake, or plasma to interstitial fluid shift
-clinical manifestations r/t loss of vascular volume as well as CNS effects
treatment: replace water and electrolytes with balanced IV solutions
extracellular fluid volume imbalance (hypervolemia) -
fluid volume excess
-excessive intake of fluids, abnormal retention of fluids, or interstitial to plasma fluid shift
-clinical manifestations r/t excess volume
treatment: remove fluid without causing change in electrolyte composition or osmolarity of
ECF
electrolytes -
sodium: hyponatremia / hypernatremia
potassium: hypokalemia/hyperkalemia
calcium: hypocalcemia/hypercalcemia
magnesium: hypomagnesemia/hypermagnesemia
phosphorus: hypophosphatemia/hyperphosphatemia
chloride: hypochloremia/hyperchloremia
sodium -
imbalances typically associated with parallel changes in osmolality
-plays a major role in:
ECF volume and concentration
generation/transmission of nerve impulses
muscle contractility
acid-base balance
hypernatremia -
elevated serum sodium occurring with water loss or sodium gain
-causes hyperosmolality leading to cellular dehydration
primary protection is thirst from hypothalamus
hypernatremia manifestations: -
3|Page
