Chapter 42: Fluid and Electrolytes Flashcards
Body fluids contain
electrolytes such as Na+ and K+, and also have a certain degree of acidity
Fluid, electrolyte and acid-base balances within the body maintain
the health and function of all body sytems
The characteristics of body fluids have
regulatory mechanisms that keep them in balance
Characteristics of body fluids include
- fluid amount (volume)
- concentration (osmolarity)
- composition (electrolyte concentration)
- acidity (pH)
Body fluid
water that contains dissolved or suspended substances such as glucose, mineral salts and proteins
Approximately ____ of an adult male’s body weight is water…. decreasing to ____ in older men
60%
50%
Women have _____ water than men
less (less muscle mass, more adipose)
Why do obese people have less water than lean people?
fat contains less water than muscle
Extracellular Fluid
outside the cells.
in adults, this accounts for 1/3 of total body water.
ESF has 2 major divisions and 1 minor division, what are they?
- intravascular fluid
- interstitial fluid
- transcellular fluid (minor)
Intravascular fluid
liquid portion of the blood (plasma)
Interstitial fluid
located in-between the cells and outside the blood vessels
Transcellular fluid
cerebrospinal, pleural, peritoneal, and synovial fluids (secreted by epithelial cells)
Intracellular Fluid
inside the cells.
in adults, this accounts for 2/3 of the total body water.
electrolytes
a compound that seperates into ions (charged particles) when dissolved in water
2 types of electrolytes
cations and anions
cations
+ charge (Na+, K+, Mg++)
anions
- charge (Cl-, HCO3-)
Types of Solutions
- isotonic
- hypertonic
- hypotonic
isotonic
the molecular concentration of dissolved solutes is the same on both sides of the cell membrane (NS=0.9% sodium)
hypertonic
contains more dissolved particles (Na+ and other electrolytes) than is found in normal cells.
water is pulled out of cells (3-5% NaCl)
hypotonic
contains less solute (salt and other electrolytes) than is found in normal cells
water is pulled into the cell (.45NS)
What are the ways in which water and electrolytes move in and out of a cell?
- active transport
- diffusion
- osmosis
- filtration
Active Transport
Requires energy in the form of ATP to move electrolytes across cell membranes against the concentration gradient going from low to high concentration (giving it what the cell needs) .
Example: Sodium-Potassium pump
What electrolytes have a higher concentration in the ICF?
K+, mg++, and PO43−
What electrolytes have a higher concentration in the ECF?
Na+, Cl−, HCO3
Diffusion
Passive movement of SOLUTES from areas of higher to lower concentrations
Osmosis
WATER that moves through a membrane that separates fluids with different particle concentrations.
Osmotic Pressure
(ICF or Interstitial) inward pulling force from the particles in a fluid
Filtration
Fluid and solutes moving into and out of capillaries between vascular and interstitial compartments due to hydrostatic pressure.
Edema
accumulation of excess fluid in the interstitial space
Heart failure
causes venous congestion from a weakened heart which increases capillary hydrostatic pressure causing EDEMA (transudate) by moving excess fluid into the interstitial space.
Conditions that can cause edema
heart failure and inflammation
inflammation
(exudate) increases capillary blood flow and allows capillaries to leak colloids (proteins) into the interstitial space = increased capillary hydrostatic pressure and increased interstitial colloid osmotic pressure = localized edema in the inflamed tissue
Fluid Intake and Absorption
occurs orally, IV or irrigation where fluid is absorbed.
normally daily intake around 2300 ml/day
Fluid Distribution
Movement of fluid among its various compartments (ECF vs. ICF, Interstitial (between cells, outside blood vessels) vs. Vascular)
Fluid can be removed from the body through
- skin
- lungs
- GI tract
- kidneys
How is fluid removed through the skin?
sensible/insensible loss (perspiration)
How is fluid removed through the lungs?
insensible loss (breathing)
How is fluid removed through the GI tract?
stool (normally only 100 ml/day) and digestion
How is fluid removed through the kidneys?
urine secretion
Abnormal fluid output includes
diarrhea, vomiting, wound drainage, or hemorrhage
Antidiuretic Hormone
influences how much water is excreted in the urine
Renin-Angiotensin-Aldosterone System
Regulates ECF volume by influencing how much Na+ and water are excreted in urine.
Also contributes to regulation of BP.
Aldosterone also contributes to
electrolyte and acid-base balance by increasing urinary excretion of K+, and hydrogen ions
Fluid Imbalances include
- volume imbalances
2. osmolarity imbalances
Volume Imbalances
disturbances in the amount of fluid in the EC compartment
hypovolemia & hyervolemia
hypovolemia
decreased vascular volume
hypervolemia
increased vascular volume
Osmolarity Imbalances
disturbances of the concentration of body fluids
hypernatremia & hyponatremia
hypernatremia
water deficit.
when interstitial fluid becomes hypertonic (increased Na+) water leaves the cells by osmosis.
S&S of hypernatremia includes
cerebral dysfunction=confusion.
hyponatremia
water excess or water intoxication.
causes water to enter cells by osmosis.
S&S of hyponatremia
cerebral dysfunctions (brain swelling)
Clinical Dehydration
when hypernatremia (increased sodium) occurs in combination with a ECF deficit
Clinical Dehydration is common with
gastroenteritis or other causes (side effects of medications such as chemotherapy) of severe vomiting and diarrhea especially when people are unable to replace their fluid output with enough intake of dilute Na+ containing fluids.
Clinical Dehydration causes
skin turgor
dry mucous membranes
Electrolyte values measured in laboratory reports are in
blood serum and do not measure intracellular levels
Potassium Imbalances
hypokalemia and hyperkalemia
hypokalemia
abnormally low K+ in the blood
<3.5 mEq/L
Causes of hypokalemia include
diarrhea, repeated vomiting, use of K+ wasting diuretics (Lasix)
S&S of hypokalemia
muscle weakness
may become life-threatening if it affects cardiac (dysrhythmias) and respiratory muscles (cardiac and respiratory cells can not repolarize)
hyperkalemia
abnormally high K+ in the blood
> 5 mEQ/L
Causes of hyperkalemia include
: increased K= intake and absorption, shift of K+ from cells to the ECF, and decreased K+ output
S&S of hyperkalemia
people with oliguria (low urine output less than <30cc/hr for 2 hours) at high risk.
muscle weakness becoming life-threatening if causes cardiac dysrhythmias (severe Bradycardia)=cardiac arrest.
hypocalcemia
low Ca++.
S&S of hypocalcemia
increased neuromuscular excitability
hypercalcemia
high Ca++
hypercalcemia can be found in
Patients with disorders to the parathyroid or osteoporosis.
hypocalcemia can be found in
Acute pancreatitis (Ca++ binds to undigested fat and is excreted.
S&S of hypercalcemia
decreased neuromuscular excitability-lethargy
hypomagnesemia
low magnesium levels
S&S of hypomagnesemia
increased neuromuscular excitability, hyperactive deep tendon reflexes (seizures) (similar to Hypocalcemia)
hypermagnesemia
increased magnesium levels
hypermagnesemia can be found in
end stage renal disease
S&S of hypermagnesemia
caused by decreased neuromuscular excitability-lethargy and decreased deep tendon reflexes most common
Normal arterial pH
7.35-7.45
Acid-base balance is regulated by
the kidneys and lungs through H+ ions and CO2 respectively
acidosis
blood too acidic
alkalosis
blood too basic
Respiratory Acidosis
Alveolar hypoventilation-lungs do not excrete enough CO2
Kidneys compensate by increasing excretion of metabolic acids in the urine (ie: lactic or citric acid
Respiratory Alkalosis
Alveolar hyperventilation. Usually short-lived.
Metabolic Acidosis
occurs from an increase of metabolic acid or decrease of base (HCO3) as in diarrhea
Compensation occurs through the respiratory system through hyperventilation
Metabolic Alkalosis
Common causes include vomiting and gastric suctioning.
Hypoventilation is the compensatory mechanism. S&S may be absent
S&S of Respiratory Alkalosis
excitement, confusion, and paresthesias (numbness and tingling in extremities)
Assess your patient’s home management of fluid imbalances to
teach how to prevent he imbalances from occurring in the future
Risk Factors for fluid and electrolyte imbalances include
- age
- environment
- dietary intake
- lifestyle
- medications
Risk Factors: Age
very young and very old at risk.
elderly at additional risk of delayed recovery
Risk Factors: Dietary Intake
Starvation diets or those with high fat and no carbs (Atkins-Ketosis) may lead to metabolic acidosis.
Assess ability to chew/swallow
Risk Factors: Lifestyle
Alcohol consumption causes Hypomagnesemia.
Elderly: medications, withholding fluids to prevent incontinence/nocturia
Risk Factors: Medications
K+ wasting diuretics, using baking soda as an antacid, use of laxatives
When assessing medical history, assess for
- acute illness or trauma
- chronic illness
- physical assessment
Acute Illness or Trauma to assess for include
GI alterations: diarrhea, vomiting
Respiratory Disorders: bacterial pneumonia
Acute Oliguric Renal Disease: due to meds or disease
Burns: high risk for ECV deficit, infection
Trauma: hemorrhage = ECV deficit
Crush injuries cause
massive release of intracellular K+ into the blood
Chronic Illnesses to assess for include
cancer
heart failure
oliguric renal disease
How does cancer affect fluid and electrolyte imbalances?
cancer cells may secrete chemicals that circulate into bones and cause Ca++.
Side effects from chemotherapy including anorexia and diarrhea
How does heart failure affect fluid and electrolyte imbalances?
reduces kidney perfusion due to decreased cardiac output, increased risk for low K+ due to ECV excess (aldosterone causes increase in absorption of Na++ and water).
Na++ restriction important
How does Oliguric Renal Disease affect fluid and electrolyte imbalances?
chronic kidney disease leads to chronic oliguria resulting in ECV excess, increased K+, increased Mg++, and metabolic acidosis
Daily Weights
most reliable indicator of fluid volume status
Diligent Intake and Output
All intake including meds
All output including drains, emesis, gastric secretions
Physical Assessment of Fluid and Electrolyte Imbalances include
- daily weights
- diligent intake and output
- edema
- lung sounds
- monitor laboratory values
Nursing Diagnosis for Fluid and Electrolyte Imbalances
Decreased cardiac Output Acute Confusion Risk for Electrolyte Imbalance Deficient Fluid Volume Excess Fluid Volume Impaired Gas Exchange Deficient Knowledge regarding Disease Management
DO NOT delegate administration of
IV fluid and hemodynamic assessment to the NAP
People of all ages need to replace body fluid losses with
sodium-containing fluid and water
Teach patients to recognize
risk factors for developing imbalances and implement appropriate preventative measures
Fluid Replacement Therapy includes
- enteral replacement
- parenteral replacement
- IV therapy
enteral replacement
Oral replacement or via a tube placed directly in the stomach, jejunum or duodenum
The nurse should watch for what in a patient undergoing enteral replacement?
watch for patients at high risk for aspiration
oral trauma or mechanical obstruction of the GI tract
Parenteral Replacement
Via IV catheter
parenteral nutrition
Parenteral Nutrition
via central line
TPN
highly concentrated solution containing nutrients and electrolytes
Many IV solutions require the use of an
EID Electronic Infusion Device
IV Therapy
fluid and/or electrolyte replacement via catheter into a peripheral vein
hypertonic, isotonic or hypotonic solutions
Additives to solutions (na++, K+) can cause
serious harm.
Administer with caution and strict monitoring.
Remember that anything liquid at room temperature is
considered a fluid
ice chips, jell-O, ice cream
Vascular Access Devices include
peripheral catheters (short term) central catheters and implanted ports (long term)
Central Catheters and Implanted Ports include
PICC lines Vas Cath (dialysis
It is critical to take measures for
the prevention of catheter-related bloodstream infections
Assess the IV site to
prevent the accidental disruption of an IV system
When assessing the IV site, assess for S&S of
infiltration
extravasation
phlebitis
infiltration
when the IV catheter becomes dislodged or a vein ruptures and IV fluids inadvertently enter SQ tissue around the IV site
extravasation
When IV fluid that contains additives that damage tissue infiltrate.
S&S: coolness, paleness, swelling of the area
Phlebitis
inflammation of a vein; chemical, mechanical, or bacterial causes
Risk factors for phlebitis include
acidic or hypertonic IV solutions rapid IV rate IV drugs such as KCL and vancomycin VAD inserted in area of flexion poorly secured catheter poor hand hygiene lack of aseptic technique.
S&S of phlebitis
redness, warmth, tenderness, possibly a red streak up the arm/extremity
Objectives for administering blood and/or blood products include:
- To replace or increase circulating blood volume after surgery or trauma, or hemorrhage (watch for S&S of fluid overload p. 913)
- To increase the number of RBCs and maintaining hemoglobin levels in patients with severe anemia
- Provide selected cellular components for replacement such as platelets, albumin, or clotting factors
Blood Transfusion Reaction
an immune response to the transfused blood components
Autologous (Auto) Transfusion
the collection and reinfusion of the patient’s own blood either pre-planned (patients donating their own blood pre-op) or from collection devices (chest tube drainage).
Before doing a blood transfusion
Together two RN’s check the blood label against the unit of blood itself, medical record number, and patient’s blood bank ID and name band
DO NOT administer even for a minor discrepancy
Transfusion reactions may be
be life threatening; know your hospitals policy and procedure for handling a transfusion reaction.
