fluid and electrolytes

homeostasis

the stable internal environment of our body

kidneys

the 1st line of protection for fluid problems

lungs

the 1st line of protection for pH

female: 55% male: 65% (more muscle mass and leaner)

percent of water in female and males

-age -gender -lean body mass

variations of water content are dependent on what 3 factors

lower water content

what happens to water content when you have a higher fat content (obese people have this problem)

higher risk for fluid problems

what happens to the risk of fluid problems when you have lower water content (older people have this problem because they have less muscle mass)

10%: serious 20%: fatal

if water intake and output becomes unbalanced what does it mean if 10% or 20% of body fluids is lost

infant and geriatric

who is at a greater risk when body fluids are lost

body weight

best indicator of fluid volume is

-same time -same clothes -same scale -in the morning after voiding

when and how should patients be weighed

1 liter of fluid

1 kg or 2.2 pounds is equal to how many liters

both overload and deficit should be weighed daily

should you be weighed daily if you are fluid overload or fluid deficit (dehydrated)

-all fluid present within the cells -65% of total body water

intracellular fluid (2 things)

-fluid found outside the cell -35% total body water -interstitial -plasma -transcellular

extracellular fluid (5 things)

interstitial fluid

fluid found between cells - provides nutrients to cells and removes waste

plasma

fluid in the intravascular system

transcellular fluid

fluids located in GI, respiratory, urinary tracts, intraocular and cerebrospinal fluid, pleural fluid around lungs, synovial fluid in joints, peritoneal fluid in abdomen, and pericardial fluid around heart

GI tract

the amount of fluid in our transcellular spaces varies throughout the day mainly due to loss and gain in

extra fluid in interstitial space

where is fluid from edema found

capillary wall and cell membrane

extracellular and intracellular fluid are separated by

osmosis

the movement of water through a semipermeable membrane form an area of higher water concentration to an area of lower water concentration

equalize water and solute concentration on both sides of the membrane

goal of osmosis

high water content

low solute concentration means what for water

low water content

high solute concentration means what for water

diffusion

movement of solutes from an area of higher concentrations to an area of lower concentrations

osmolality

amount of solutes per kilogram of water (refers to body fluids)

-same -the body's water balance

osmolality is approximately the ( ) in various body fluid spaces; determining osmolality is important because it indicates

-plasma osmolality -the number of solutes per kilogram of fluid in the body -(can also measure in urine)

to measure osmolality we measure or estimate

270-300

normal osmolality

300

concentration of particle is too great or that water content is too little (osmolality number)

<270

concentration of particles is too little for the amount of water

water deficit (high solute)

what does high osmolality mean for water

water excess (low solute)

what does low osmolality mean for water

tonicity

the ability of solutes to cause the movement of water across a membrane from one compartment to another

tonicity

what can osmolality be affected by

-isotonic -hypotonic -hypertonic

fluids are classified as

isotonic

IV solutions that have the same concentration of solutes a blood plasma

they stay on our vascular system and do not pull any extra fluid from any other components

where does the fluid from isotonic solutions go to

hypotonic

IV solutions have lesser concentration of solutes than plasma

they shift from our extracellular fluid to our intracellular fluid (from vascular system to cells)

where does the fluid from hypotonic solutions go to

swell

what happens to cells with hypotonic solutions

hypertonic

solutions have greater concentration of solutes than plasma

they shift from intracellular fluid to extracellular fluid (cells to vascular system)

where does the fluid from hypertonic solutions go to

shrink

what happens to cells with hypertonic solutions

-0.9% sodium chloride (normal saline) -lactated ringer's (LR) -5% Dextrose with Normal saline (D5NS)

fluids that are or act like isotonic solutions

-isotonic solution of choice for expanding ECF volume -used to correct extracellular fluid volume deficit -used for administration of blood products -used to replace sodium loses (hyponatremia)

uses for 0.9% sodium chloride (normal saline)

-should use with caution in patient with heart failure, pulmonary edema, and renal impairment

caution for 0.9% sodium chloride (normal saline)

-used to correct fluid volume deficit, hyponatremia, fluid losses caused by burns, wound drainage and trauma -given more in ER or OR situations (patients lost more than just fluid, they need everything)

uses for lactated ringer's (LR)

-should not be given to patients who cannot metabolize lactate (liver disease) -should use with caution in patients with heart failure, pulmonary edema, and renal impairment (can cause fluid overload)

caution for lactated ringer's (LR)

-water -sodium -potassium -calcium -chloride -lactate

what is in lactated ringer's (LR)

-technically hypertonic but when dextrose is metabolized it provides sodium chloride which makes it work like a isotonic solution -used in patients with fluid deficit in need of extra calories due to high metabolism or excessive loss such as in surgery -diabetic patients with low blood sugar, NPO after surgery, malnourished

uses for 5% dextrose with normal saline (D5NS)

-document baseline data (before infusion assess vital signs, edema status, and lung sounds. continue to monitor during and after infusion) -observe for signs of fluid overload (hypertension, bounding pulse, crackles, dyspnea, edema, jugular vein distention)

nursing considerations for isotonic solutions

-0.45% sodium chloride (1/2 normal saline) -5% dextrose in water (D5W) -0.225% sodium chloride solution -5% dextrose with 1/2 normal saline (D51/2NS)

fluids that are or act like hypotonic solutions

-used for replacing water in patients who have hypovolemia with hypernatremia

uses for 0.45% sodium chloride (1/2 normal saline)

-excessive use may lead to hyponatremia due to the dilution of sodium -should not be used in patient with increased intracranial pressure - may cause brain cells to swell which will worsen condition

caution for 0.45% sodium chloride (1/2 normal saline)

-technically isotonic but when dextrose is metabolized it provides free water which makes it work like a hypotonic solution -expands ECF and ICF -used to treat hypernatremia

uses for 5% dextrose in water (D5W)

-should not be used in fluid resuscitation because of risk of hyperglycemia -should not be used in patient with increased intracranial pressure - may cause brain cells to swell which will worsen the condition

caution for 5% dextrose in water (D5W)

-used as maintenance fluid for pediatric patients as it is the most hypotonic fluid available

uses for 0.225% sodium chloride solution

-technically hypertonic but when dextrose is metabolized it provides sodium chloride which makes it work like a hypotonic solution -often used as a maintenance fluids for elderly, pediatric and post op -used in patients with intracellular fluid deficit in need of extra calories due to high metabolism or excessive loss such as surgery

uses for 5% dextrose with 1/2 normal saline (D51/2NS)

-observe for signs of worsening hyponatremia (vascular collapse) -caution in patient with increased intracranial pressure (IICP) (can cause cerebral edema) -warning on excessive infusions (ICF depletion, decreased BP, cellular edema and cell damage) -do not administer with blood products (hemolysis of RBC)

nursing considerations for hypotonic solutions

-3% sodium chloride (NaCl) -5% sodium chloride (NaCl) -10% dextrose in water (D10W)

fluids that are or act like hypertonic solutions

-used to treat acute treatment of severe hyponatremia (sodium level of 115 or less) -used in patients with cerebral edema -some patients may need diuretic therapy to assist in fluid excretion

uses for 3% NaCl and 5% NaCl

-should be infused at a very low rate to avoid risk of fluid volume overload

caution or 3% NaCl and 5% NaCl

-used in the treatment of malnutrition, provides calories and free water

uses of 10% dextrose in water (D10W)

-best if administered using a central line due to vein irritation and cause dilution from rapid blood flow

caution of 10% dextrose in water (D10W)

-document baseline data (vital signs, edema status, lung sounds. before, during, and after infusion) -watch for signs of hypervolemia (increased fluid) -monitor and observe the patient during administration -assess health history (caution in kidney or heart disease) -do not administer peripherally (irritation and damage to the blood vessel)

nursing considerations for hypertonic solutions

-given to patients who's GI tract cannot be used or cannot absorb nutrition adequately -unconscious and don't want to place a G-tube, bowel obstructions, post-op, history of GI difficulties who need nutrition

who cannot have total parenteral nutrition

-must be given through a central line -peripheral veins can be used for short periods of time and low hypertonic solutions (PRN)

where can TPN be placed

-evaluate need on a daily basis and solution mixed everyday based on daily labs -monitor daily weights, vital signs, labs, I and O, blood sugar -increase rate of infusion slowly (start at 40-60ml/hr and then as tolerated meet goal set by dietitian) and decrease rate slowly -patient will be put on sliding scale insulin -change tubing and solution every 24 hours even if not complete -use sterile technique when inserting huber needle or changing dressing around central line, make sure to use the correct tubing with a secure and uncontaminated connection

nursing interventions for TPN

-1 liter bag with about 1000cal/liter -special tubing with a filter and special pump made for tubing -stored in refrigerator, can take out and let warm up before giving

how does TPN come

-antidiuretic hormone (ADH) -renin, angiotensin and aldosterone -hydrostatic pressure

mechanisms controlling fluid and electrolyte balance

-low blood volume and increased osmolarity are sensed by hypothalamus, which signals the pituitary gland -the pituitary gland secrete ADH into bloodstream -ADH causes the kidneys to retain water and decrease urine production -water retention boosts blood volume and decreased serum osmolality (if there is increased blood and decreased serum osmolality it will inhibit release of ADH and cause less water to be reabsorbed and the urine less concentrated. (body hold water when fluids drop and releases when they rise)

how does the antidiuretic hormone work (ADH)

-Blood flow to glomerulus drops or blood pressure drops. Cells secrete renin into the bloodstream -Renin travels to the liver where renin converts angiotensinogen to angiotensin I -Angiotensin I travels to the lungs where angiotensin I is converted into angiotensin II -Angiotensin II travels to the adrenal glands which are then stimulated to produce aldosterone -Aldosterone causes the kidneys to secrete potassium and retain sodium which results in retention of water as well -Sodium and water retention leads to increases in fluid volume and sodium levels (balance sodium and water in body with healthy blood volume and blood pressure) (angiotensin II is a vasoconstrictor that increases BP. when BP reaches normal levels the body stop releases renin and the process stops)

how does renin, angiotensin, and aldosterone work

hydrostatic pressure

the blood pressure generated by the contraction of the heart

-gradually decreases as the blood moves through arteries until it reaches capillaries -at the capillaries, the pressure is the major force that pushes water out of the vascular system and into interstitial space (plasma proteins (albumin) creates osmotic pressure (high solutes) preventing too much water from leaving the vascular system)

how does hydrostatic pressure work

edema

accumulation of fluid in the interstitial space -shift from plasma to interstitial space

-hypertonic solution -elastic compression stockings or hose

what can help shift fluid back into capillaries

1st spacing

normal distribution in the intracellular and extracellular spaces

2nd spacing

an excess of fluid accumulation between the cells (interstitial)

3rd spacing

accumulation of fluid in areas where normally there is minimal fluid. fluid gets trapped and is unavailable for functional use (ascites, pleural effusion, edema from burns, trauma or sepsis) -can lead to hypovolemia and circulatory collapse (insufficient blood flow to organs)

-dependent edema -below the heart (arms, legs, feet)

most common type of edema and where does it collect

-pitting edema (1+ - 4+) -daily weights -abdominal girth (pitting is based on every 2mm or every 2 seconds)

assessing edema

-GI loss from vomiting, diarrhea, and NG suction -increased perspiration during strenuous exercise or extreme heat without adequate fluid replacement -hemorrhage -excessive loss of fluid from a wound

excessive loss of fluids examples

-nausea, anorexia, inability to swallow -altered thirst mechanisms which decrease the recognition of the need to drink or inability to communicate thirst (geriatric people tend to lose their sense of thirst)

insufficient intake of fluid examples

-aggressive treatment of fluid volume excess with diuretics -third spacing -administration of salt tablets

fluid shifts examples

-increased serum osmolality -increased urine specific gravity -increased urine osmolality -decreased hemoglobin and hematocrit if blood loss -increased hemoglobin and hematocrit if just a loss of fluids (dehydration) -increased BUN and creatinine (decreased renal perfusion and function with dehydration) -hypernatremia if there has been just water loss -hypokalemia if severe GI fluid loss resulting in inability of colon to reabsorb potassium (kidneys working to conserve water for osmolality and specific gravity)

hypovolemia fluid volume deficit lab values

-weight loss -loss of skin turgor -temperature changes (high or low) -concentrated urine output -oliguria (low urine output) -thirst -dry mucous membranes -weak, rapid pulse -flattened neck veins -hypotension -tachypnea, hypoxia -anxiety, confusion -restlessness, weakness -cool, clammy, pale skin

hypovolemia fluid volume deficit manifestations

-if not severe increase intake of oral fluids -if deficit is rapid and severe or intake isn't feasible, IV isotonic solutions (0.9% NaCL or LR), once blood pressure and electrolytes are corrected IV hypotonic solutions are used as maintenance fluids -close assessment of urine output, daily weights, vital signs, pulmonary status, and lab values, LOC, urine color and concentration, skin turgor, dry skin

treatment of hypovolemia

-cirrhosis -heart failure -stressful conditions causing the release of ADH and aldosterone -use of corticosteroids -excessive amounts of IV fluid administered (containing sodium) -ingestion of excessive amounts of salt in the diet -renal failure (reduced excretion of sodium and water) -interstitial plasma shifts (administration of hypertonic fluids) -SIADH (inappropriate antidiuretic hormone - high levels of a hormone cause the body to retain water) -(chronic stimulus of kidneys to conserve sodium and water for HF, cirrhosis, corticosteroids)

hypervolemia fluid volume excess causes

-decreased serum osmolality -decreased urine specific gravity -decreased urine osmolality -decreased hematocrit -hyponatremia -may see decreased BUN (all due to hemo-dilution)

hypervolemia fluid volume excess lab values

-weight gain -ascites -edema -increased urinary output -hypertension -tachycardia -jugular vein distention (blood backs up right side of heart) -cough -tachypnea -wheezing/crackles -orthopnea -decreased oxygen saturation

hypervolemia fluid volume excess manifestations

-limiting daily intake of fluid and sodium -monitoring daily weights -terminating IV fluids if they are being administered -diuretics (renal dysfunction who do not response to diuretic may need renal dialysis, watch for hypokalemia) -oxygen therapy if patient is having respiratory manifestations, position in semi-fowler's -vasodilator such as nitroglycerin (promote venous dilation and decrease workload of heart) if patient is having cardiac manifestations

hypervolemia fluid volume excess treatments

electrolytes

substances whose molecules split into ions when placed in water. ions are either positively charged (cation) or negatively charged (anion)

-potassium (K+) -sodium (Na+) -magnesium (Mg+) -calcium (Ca+)

cations

-chloride (Cl-) -phosphate (PO4-) -sulfate (SO4-) -bicarbonate (HCO3-)

anions

regulate water distribution and regulate acid base balance

main function of electrolytes

-potassium (K+) -Phosphate (PO4-)

main electrolytes in intracellular fluid

-sodium (Na+) -chloride (Cl-)

main electrolytes in extracellular fluid

3.5-5.0 meq/L

normal potassium level