95 terms

Assessment and Care of Patients with Fluid and Electrolyte Imbalances

water portion of fluids
particles dissolved or suspended in water
hydrostatic pressure
the force that pushes water outward from a confined space through a membrane
"thickness" of a fluid
no pressure differences between the two spaces due to equal hydrostatic pressure
occurs when a gradient of unequal pressures exist across a membrane
Average amount of urine per day
1.5 L
movement of fluid through a cell or blood vessel membrane due to hydrostatic pressure differences on both sides of the membrane
How is blood pressure an example of hydrostatic filtering force?
It moves whole blood from the heart to capillaries where filtration can occur to exchange water, nutrients, and waste products between the blood and tissues
Edema develops when...
increases in venous capillary pressure rise and force fluid into the interstitial tissues
free movement of particles across a permeable membrane from an area of high concentration to low concentration
-movement of water through a semi-permeable membrane
-Water moves from low to high concentration to achieve homeostasis
What is the thirst mechanism?
The feeling of thirst is caused by the activation of cell in the brain that responds to changes in the ECF osmolarity
Normal Osmolarity
270-300 mOsm/L
-fluid left in interstitial tissue following a movement of fluids from the capillary at it's arterial end and back to venous capillary system
-Lymph flow is slower than blood flow
What is lymph flow enhanced by?
-skeletal muscle contractions
-lymphatic peristalsis
What is flood intake regulated by?
thirst drive
What triggers the thirst drive?
increased osmolarity
decreased blood volume
Measurable fluid intake
oral fluids
parenteral fluids
irrigation fluids
Non measurable intake
solid foods
Minimum amount of urine needed to excrete toxic waste products
400-600 mL/day
Insensible water loss
fluid loss through skin, lungs, and stool
cannot be controlled or measured
average water loss for healthy adult
500-1000 mL/day
secreted by adrenal cortex when sodium level in ECF in decreased
prevents both water and sodium loss
Antidiuretic hormone (ADH)
stored in posterior pituitary gland
acts on renal tubules in response to changes in blood osmolarity causing water retention
Natriuretic peptides
hormones secreted by special cells in the atria (ANP) and ventricles (BNP) of the heart in response to increased blood volume and pressure
***Opposite of aldosterone- increases urine output to reduce circulating blood volume
When does BNP increase?
Fluid intake is less than what is needed to meet the body's fluid needs, resulting in fluid volume deficit
Actual dehydration
decrease in total body water
Relative Dehydration
intravascular water shifts out of circulating blood volume into the interstitial (extravascular) space
Where do you assess skin turgor in older adults?
skin over sternum or on forehead
Assessment for DEHYDRATION
I&O record
Physical assessment & clinical manifestations of DEHYDRATION
orthostatic hypotension
flattened neck veins in supine position
decreased turgor
decreased moisture
dry mucous membranes
change in mental status
concentrated urine (increased spec. grav.)
decreased urine output (<500 mL/day cause for concern)
Lab assessment for DEHYDRATION
Hgb, Hct, Serum Osmolality, glucose, protein, BUN, and electrolytes
(All increased because decreased extracellular volume)
Fluid overload
excess of body fluid
-most common causes are related to fluid volume excess in the vascular space or to dilution of specific electrolytes and blood components
Assessment of FLUID OVERLOAD
pitting edema
bounding pulses
distended neck veins
(Report >3 lb weight gain/week OR >1-2 lbs in 24 hrs.
Sodium normal range
136-145 mmol/L
Nursing care priority for hyponatremia
monitor pts. response to therapy and prevent hypernatremia and fluid overload
Normal potassium range
3.5-5.0 mEq/L
ECG changes in HYPOkalemia
flattened T wave, appearance of U wave
Nursing care for HYPOkalemia
ensures adequate oxygenation, patient safety for falls prevention, prevent injury from potassium administration, monitor pts. response to therapy
Most severe problems from HYPERkalemia
Cardiovascular changes due to ECG changes
Major cause of death in hyperkalemia
(ventricular ectopy, heart block, systole, or ventricular fibrillation)
Normal CALCIUM range
9.0-10.5 mg/dL
Trousseau's sign
palmar spasm with arterial occlusion with BP cuff for 1-4 min.
Chvostek's sign
tap the face in front and below ear to assess for twitching
Musculoskeletal weakness in HYPOphospatemia may progress to...
Normal Phosphorus levels
3.0-4.5 mg/dL
What does it mean when CALCIUM and PHOSPHORUS are in a balanced reciprocal relationship?
If Calcium increases, Phosphorus decreases
If Calcium decreases, Phosphorus increases
Normal Magnesium levels
1.3-2.1 mg/dL
What is a major nursing intervention for HYPERmagnesemia?
Discontinue all oral and parenteral magnesium
Normal Chloride levels
98-106 mEq/L
Most common reasons for Infusion Therapy
-maintain or correct fluid balance
-maintain or correct electrolyte or acid-base balance
-Administer medications
-Replace blood or blood products
Normal serum osmolarity for adults
270-300 mOsm/L
Parenteral solutions within normal range are...
Fluids greater than 300 mOsm/L are...
Fluids less than 270 mOsm/L are...
Patient's receiving ISOTONIC solutions are at risk for...
fluid overload
-when isotonic infusions are used, water does not move into or out of the body's cells
3-5% NS
How do HYPERTONIC infusions work?
move water out of the body's cells (ICF) by osmosis and into the bloodstream (ECF)
Complications with HYPERTONIC infusions
vascular overload (increased ECF)
pulmonary edema
cellular dehydration (decreased ICF)
1/4 NS
0.45% NS
Complications with HYPOTONIC infusions
causes cells to burst or lyse (increased ICF)
serum (decreased ECF) dehydration
increased serum electrolytes due to hemoconcentration
Vascular Access Device (VAD)
-Where are they used?
-How long can they dwell in a vein?
superficial veins of the hand and forearm
dwell for 72 to 96 hours and then require removal
How do you remove a PICC line?
1-2" at a time, over 1-2 minutes (relaxes, prevents vasospasm, breakage)
MEASURE CATHETER*** make sure you take as much as you gave
Tunneled Central Catheter
portion of catheter lying in a subcutaneous tunnel separates the point at which the catheter enters the vein from where it exits the skin

used for infusion therapy that is frequent and long-term
Implanted Ports
A subcutaneous pocket is surgically created to house the port body
Port is usually placed in the upper chest or the upper extremity
Port needs to be flushed after each use and at least once a month between courses of therapy
(Most facilities require a heparin-lock flush upon discontinuing infusions
Dialysis Catheters
Lumens are very large to accommodate the hemodialysis procedure or a pheresis procedure that harvests specific blood cells
Should not be used for administration of other fluids or medications, except in an emergency
What type of administration set is used when no primary line is present?
Ex: Antibiotic without continuous infusion line
Needleless connection devices
Used to minimize risk for needle sticks
Slip-lock add-on system
Memorial has them, male and female end
Luer-lock add-on system
threaded end that screw together
Circulatory overload
homeostasis disruption due to excess fluid
Speed shock
rapid infusion of drugs or bolus infusion that causes shock or cardiac arrest due to introduction of a foreign substance
Allergic reaction
may be to tape, cleansing agent, solution, or IV device
Catheter embolism
Piece of catheter breaks off causing it to freely float in the blood vessel
Arterial therapy
Used for pressure monitoring, repeated blood gases, & to infuse some chemotherapy agents
Intraperitoneal infusion
placement of chemotherapy agents into the peritoneal cavity
Suncutaneous infusion
slow infusion of isotonic fluids into the subcutaneous tissue, short term fluid replacement
torso preferred site
Intraspinal infusion
Administration of opioids and anesthetics for regional pain relief, also steroids and antispasmodics

Ex: Epidural, Subarachnoid injection
Intraosseous therapy
Easy access in the proximal tibia or sternum
Used mostly in pediatric population
Now used for trauma, burn, or cardiac arrest victims
Short duration (24 hours), but as effective as peripheral or central IVs for large volume infusions
What does a "pins and needles" sensation indicate?
nerve puncture
adrenal gland hormone that causes kidneys to reabsorb sodium into the blood, causing more water to be reabsorbed by osmosis
condition in which that plasma is more dilute than normal
a state of fluid volume excess or overload in the blood stream
concentration of solute per kilogram of water, which creates the pulling power of that solution for water
concentration of solute per liter of solution, which creates the pulling power of that solution for water
vascular space
space within the blood vessels
normal fluid volume in the body
relative hyperkalemia
movement of potassium from the intercellular fluid to the extracellular fluid, leading to elevated serum potassium levels without a true body increase of K+, such as occurs with acidosis
relative hypokalemia
movement of potassium fro the ECF to the ICF, leading to lowered K+ levels without a true decrease of K+ in the body, such as occurs with insulin therapy
ECG changes for hyperkalemia
wide QRS, tall tented T-wave, ST segment depression
ECG changes for hypokalemia
Flattened T wave, Normal QRS, ST segment depression