Chapter 41: Fluid and Electrolyte Practice Test Flashcards
Fluids & electrolytes help to maintain ______ in body
homeostasis
State of equilibrium
homeostasis
Chemical reactions dependent on _______
F & E balance
Normal water content in an Adult Male is?
60% of TBW
Normal water content in an Adult female is?
50-55% of TBW
Normal water content in the elderly is?
45-55% of TBW
Normal water content in an infant is?
70-80% of TBW
What is the solvent in which body salts, nutrients, and wastes are dissolved and transported?
water
______ need to be in correct balance for cells to function properly
Electrolytes
What are the Primary electrolytes in body
Na+, K+, Ca2+
Other: Cl, Mg, Bicarb (HCO3), Phosphates (PO4), Sulfates (SO4)
Name 2 functions of electrolytes
- substances which split into ions when dissolved in water
2. able to carry an electrical current
Has About 40% of total body weight (TBW) &
Maintains cell size & function
Intracellular fluid (ICF)
Name 2 body fluid compartments
intracellular fluid and extracellular fluid
Name the fluid inside blood (plasma) (5%)
Intravascular fluid
ISF (interstitial fluid) includes what components and functions?
lymph, transports O2, nutrients, hormones, & other chemicals between blood & cell cytoplasm
The fluid between cells, outside vascular space is?
Interstitial fluid (ISF)
The small amount of fluid in GI tract, cerebrospinal fluid, pleural, synovial, & peritoneal fluids
Transcellular space
Extracellular fluid contains _____,_______,_____:
intravascular, interstitial and the transcellular space
Body shifts fluid to keep osmolality (concentration of dissolved substances) balanced between 3 fluid spaces. What are those spaces?
plasma, interstitial fluid and intracellular fluid
Fluids & electrolytes (solutes) constantly shift between compartments by 4 processes. What are they:
Osmosis
Diffusion
Filtration
Active Transport
Body tries to keep osmolality balanced in the 3 fluid compartments by?
shifting fluid or solutes
Kussmaul respirations Changes in LOC Disorientation Muscle twitching Low PH Low HCO3
What acid-base imbalance is this?
Metabolic Acidosis
Rapid, shallow respirations Dyspnea Muscle weakness Low pH High CO2
What acid-base imbalance symptoms are these?
Respiratory Acidosis
Slow respirations Restlessness Diarrhea Nausea & Vomiting Arrhythmias High PH High HCO3 What acid-base imbalance symptoms are these?
Metabolic Alkalosis
Deep rapid breathing Seizures Confusion Tingling of Extremities High pH Low CO2 What acid-base imbalance symptoms are these?
Respiratory Alkalosis
movement of solvent (water) across semi-permeable membrane from area of lower concentration to higher
Osmosis
a higher solute concentration pulls fluid into that space
Osmotic pressure
Blood has _____________ due to plasma proteins
colloid osmotic pressure AKA oncotic pressure
Keeps fluid from leaking out of vascular space
colloid osmotic pressure AKA oncotic pressure
_______ is especially important to keep fluid from shifting out of intravascular space
Albumin
If pancreas doesn’t produce enough insulin or if body is resistant to using insulin, glucose is not able to diffuse across cell membrane to be utilized.
Which disease does this cause?
Diabetes
movement of solutes from higher concentration to lower
Diffusion
movement of glucose across cell membrane requires carrier molecules which bind to receptors and make the membranes more permeable to glucose
Facilitated diffusion
Movement of O2 & CO2 between alveoli & capillaries
diffusion
molecules move from area of lower to higher concentration, requires energy
Active transport –
e.g. sodium-potassium pump allows a higher concentration of K+ in ICF & higher concentration of Na+ in ECF
______and _____ are processes used to balance osmolality or solute concentration
Diffusion and osmosis
_____ is movement of fluid to balance solute concentration
Osmosis
____ is movement of both fluid and solutes to equalize solute concentration
Diffusion
transfer of water & dissolved substances through membrane from region of high pressure to region of lower pressure.
Filtration –
ex: Occurs in kidney glomerular capillaries & in blood capillaries
____ ____ is generally higher on arterial side & lower on venous side of capillaries
Hydrostatic pressure
ex: In CHF, hydrostatic pressure higher on venous side of capillary beds
Fluid moves out of vascular space into interstitial space causing what sx?
edema
Force within a fluid compartment which includes: Vascular space or tissues
Hydrostatic Pressure
Osmotic pressure exerted by proteins, (especially albumin)
Large molecules hold fluid in vascular space
Oncotic Pressure
Total milliosmoles of solute per unit of volume of solution mOsm/L
Describes fluids outside the body
Osmolarity
Osmotic force of solute per unit of wt. of solvent mOsm/kg or mmol/kg
Describes fluids inside the body
Osmolality
same concentration of particles as plasma
Isotonic -
greater concentration of particles than plasma
Hypertonic -
lesser concentration of particles than plasma
Hypotonic -
What are the 2 primary body fluid compartments?
intracellular and extracellular fluid
Fluid & electrolytes shift between compartments via which 4 processes?
Osmosis
Diffusion
Filtration
Active Transport
____ transport keeps K+ higher in ICF & Na + higher in ECF
Active
Active transport requires energy in the form of _____ _____ to move electrolytes across cell membranes against the concentration gradient
adenosine triphosphate (ATP)
fluid shift from vascular space to interstitial space
Edema –
A ↓plasma oncotic pressure due to low protein would cause
Renal disorders, liver disease, malnutrition
What causes ↑ pressure in the vascular space?
fluid overload, CHF, liver failure, obstruction of venous return, venous insufficiency
damage to capillary walls from trauma (e.g. crushing injury), burns, inflammation
Plasma proteins leak into interstitial space causes…
↑interstitial oncotic pressure
Oncotic pressure R/T protein molecules holds fluid in the vascular space
loss of extracellular fluid from the vascular to other body compartments.
Third spacing
ex: Occurs with extensive surgical procedures, burns, septic shock, liver disease
Ascites in liver disease, severe edema with burns, peritonitis
Define Third spacing
Major fluid shift from intravascular to interstitial space.
Ex: Occurs with extensive surgical procedures, burns, septic shock, liver disease
Ascites in liver disease, severe edema with burns, peritonitis
fluid in abdominal intersitial (IS) space
Ascites
Problems that may with Third spacing are?
Causes hypovolemia, hypotension, tachycardia, ↓UOP due to insufficient fluid in vascular space
During surgical recovery, fluid shifts back into vascular space and can cause fluid overload
Beer and soda are _____ fluids
hypertonic
Fluid Shift from Interstitial
Space to Plasma (vascular space) is caused by?
Caused by increase in plasma osmotic or oncotic pressure R/T:
Administration of colloids (blood products), dextran, mannitol, or hypertonic solutions
Major illness or injuries may result in _____ and ______ _____.
F & E imbalance
___ ____ ____ regulated by intake, output, & hormonal controls
Body fluid volume
Thirst control center in ____ stimulated when serum osmolality increases
hypothalmus
Regulation of Fluid Input values per day are?
Need ~ 2200-2700ml fluid input per day 1500+ from fluids 1000 from solid food 300 from metabolism 2800+ mL TOTAL
Sweat regulated by ?
sympathetic nervous system
Fluid output primarily through ?
kidneys
Insensible (not noticeable) loss occurs through ?
skin, lungs, GI tract
Note: Insensible loss ↑ w/ fever or burns
GI tract loses additional fluid through vomiting or diarrhea, use of laxatives and stool softners
What would a nurse Assess for Fluid Balance?
History Vital signs I&O balance Weight Skin turgor/moisture Mucous membranes Lung sounds JVD Edema LOC Labs
1 Liter H20 =
2.2 lb or 1 kg
who are at HIGH risk for fluid imbalances?
infants
elderly- impaired thirst mechanism →dehydration & ↑Na
↑ risk of FVE
Post-op and/or NPO
anyone Vomiting / Diarrhea
Diuretics
Chronic Disease- renal,cardiac, endocrine
what labs would be assessed for fluid imbalances?
H&H: Hemoglobin (Hgb) & Hematocrit (HCT) Electrolytes BUN Urine specific gravity concentrated (>1.025) dilute (<1.01) Serum Osmolality - FYI 275-295 mOsm/kg not a routine lab BNP Electrolytes & BUN will appear more concentrated if someone is dehydrated or hypovolemic
what is the function of BNP = brain natriuretic peptide?
Secreted in response to increase blood volume & blood pressure, which stretch heart tissue. Binds to receptor in nephrons and inhibits reabsorption of Na and water. This value is increased in CHF.
What are the Collaborative Goals for Treating
any F & E Imbalance?
Determine underlying cause through physical assessment & diagnostic testing
Correct the underlying cause
Replace deficient F & E or remove excess
Stabilize pH (acid-base balance)
What is the etiology of Hypervolemia, over-hydration
Etiology Excessive Na intake (PO or IV) Compromised regulatory systems Renal insufficiency Congestive Heart Failure (CHF) Cirrhosis Endocrine Disorders (SIADH)
What are the signs and sx of hypervolemia
Signs & Symptoms
*Weight gain
VS - ↑ BP, ↑ HR, & ↑RR Pulse quality?
dyspnea, orthopnea
Pitting edema w/ tight, shiny skin
JVD @45 degrees
Moist crackles
cough
Headache, agitation, confusion R/T brain cell swelling
Labs – blood volume is diluted, what happens?
electrolytes, H&H, Urine specific gravity
BNP – increased in CHF
What is the etiology of AKA Hypovolemia or dehydration (water loss only)
Loss of water and Na
Vomiting, diarrhea, diaphoresis, diuretics
Hemorrhage, burns cause loss of water, electrolytes, protein, RBCs
Decreased intake
NPO, anorexia, dysphagia, altered perception of thirst, unable to reach water
What are the signs/sx of hypovolemia?
Negative balance of intake/output Concentrated urine, ↑specific gravity Weight loss Dry skin/mucous membranes Poor skin turgor, tenting >20-30sec *Weakness, restlessness, confusion Concentrated Hct. & electrolytes Severe FVD → dec. cardiac output, possible shock
Intracellular fluid is made up of…
Cations (+) – mostly potassium & small amts. of magnesium & sodium
Anions (-) – mostly phosphate & protein w/ small amts. chloride & bicarb
extracellular fluid is made up of
Cations – mainly sodium w/ small amts of potassium, calcium, & magnesium
Anions – mostly chloride, some protein, w/small amts of bicarb, sulfate, & phosphate
Sodium Na+ (fyi)
Na+ aids in generation & transmission of nerve impulses and fluid balance
Main cation in ECF
Range 135-145 mEq/L
effects osmolality & water distribution between ECF & ICF
Kidneys regulate Na levels by excreting/retaining water
Aldosterone promotes Na reabsorption by renal tubules
Regulation of Electrolytes SODIUM
Plasma Na levels reflect % concentration
Abnormal Na levels may indicate water imbalance or sodium imbalance or both
Water Excess &/or Hyponatremia
(145mEq/L)
Treatment depends on cause & fluid status
potassium (fyi)
Potassium is major cation in ICF
Labs: 3.5-5.0 (slightly higher some places)
Potassium needed for conduction of nerve impulses, normal cardiac rhythm, & muscle contraction
Potassium must be obtained through diet or supplements
drops quickly if not replaced
Potassium excreted by kidneys, stool, sweat
If kidney function impaired, K+ rises
Calcium (fyi)
Ca obtained from food, combined with phosphorus & stored in bone
Ca aids in transmission of nerve impulses, myocardial contractions, blood clotting, formation of teeth & bone, muscle contractions
Serum Ca levels usually show total of 3 types
Ionized (free), bound w/protein (albumin), & complexed w/ phosphate, citrate, or carbonate
Ionized is sometimes measured separately – most important in neuromuscular functioning
Calcium balance controlled by:
Parathyroid hormone (PTH)
Stimulated by low serum Ca levels to move Ca out of bone, ↑GI absorption, & renal tubule reabsorption
Calcitonin – Produced by thyroid gland. Responds to ↑Ca. Opposite effects of PTH listed above.
Vitamin D – stimulates absorption of Ca from GI tract
protein imbalances are:
Plasma proteins (esp. albumin) are indicative of plasma volume
Protein increases oncotic pressure and pulls fluid inward into vascular space
Causes of imbalance include malnutrition, starvation, fad diets or vegetarian diets w/ insufficient protein, massive burns, liver disease, major infection, loss of albumin in renal disease, hemorrhage
S/SX: edema from ↓oncotic pressure, slow healing, anorexia, fatigue, anemia, muscle loss
Acid-Base Balance info:
Hydrogen ion concentration in the cellular environment is regulated within extremely narrow limits. This is called acid-base balance
For optimum cell functioning, body must maintain acid-base balance
Body metabolism produces acids which are buffered by body systems
What are the Factors Affecting Fluid, Electrolyte, and Acid-Base Balance?
Thirst Vomiting Diarrhea Diaphoresis Diuretic use Stress Chronic illness Renal failure Cardiac failure Respiratory failure Surgery Pregnancy
What are the sign/sx of Respiratory Acidosis
Carbonic acid & PCO2 excess: Anything which causes hypoventilation which leads to ↑CO2 patient cannot catch breath hypoventilation rapid, shallow respirations increase BP dyspnea headache hyperkalemia disorientation muscle weakness hypoxemia low pH below 7.35 high pCO2 above 45 increase cardiac output
what are the sign/sx of Respiratory Alkalosis?
Carbonic acid & CO2 deficit Anything causing hyperventilation or “blowing off” too much CO2; due to respiratory problem or other event pH often corrects self before kidneys need to compensate (would excrete HCO3) seizures deep, rapid breathing hyperventilation confusion hypokalemia lightheadedness tingling of extremities increase pH above 7.45 low PCO2 35
what are the sign/sx Metabolic Acidosis?
Acids accumulate OR bicarbonate is lost e.g. Ketoacid accumulation in diabetic ketoacidosis or starvation, ASA overdose ↑lactic acid in shock, heavy exercise HCO3 loss in severe diarrhea or renal failure headache disorientation hyperkalemia muscle twitching changes in loc Kussmaul Respirations (compensatory hyperventilation) pH below 7.35 HCO3 below 22
what are the sign/sx Metabolic Alkalosis
Base Bicarbonate Excess
Occurs w/a loss of acid or gain in bicarbonate prolonged vomiting or gastric suction (lose stomach acid) Excess ingestion of baking soda or IV bicarb restlessness followed by lethargy dysrhythmias diarrhea confusion nausea and vomiting slow respirations hypokalemia increase pH above 7.45 increase HCO3 above 26 compensatory hypoventilation
What are the signs/sx of Respiratory Compensation:
Lungs control amount of CO2 in blood
Consider CO2 an acid (carbonic acid is formed by H20 & CO2)
Hyperventilation blows off more CO2 and increases pH to compensate for metabolic acidosis
Hypoventilation retains CO2, decreases pH to compensate for metabolic alkalosis
What are the signs/sx of Renal Compensation
Renal Compensation: Kidneys help to maintain normal acid-base balance by changing rate of excretion or retention of hydrogen and HCO3 ions.
Kidneys are slower than lungs to compensate for sudden changes in acid-base status
Kidneys handle increase in blood acids by:
Increasing excretion of H+ ions into the urine and returning HCO3 ions to the blood
Additional serum bicarbonate is made available to absorb more free H+ ions, and normal pH can be reestablished
What do the blood gases mean? (fyi)
ABGs best way to determine acid-base balance
pH – hydrogen ion (H+) concentration
PaCO2 – partial pressure of CO2
reflects depth & rate of ventilation
compensates for metabolic acidosis or alkalosis
HCO3- - Bicarb is major renal component of acid-base balance & principle buffer of ECF
ECF is 20:1 bicarb to carbonic acid
PaO2 – partial pressure of O2
doesn’t affect acid-base if normal
Normal 80-100mm Hg
If < 60, leads to anaerobic metabolism, lactic acid production, & metabolic acidosis
e.g. occurs during cardiac arrest
give bicarb as part of resuscitation effort
O2 Saturation - Normal 95-99%
point at which hemoglobin is saturated by O2
If PaO2<90%, cause for concern
how do you determine Respiratory or Metabolic Imbalance?
1.Check pH (normal 7.35-7.45) to determine if patient is acidotic or alkalotic
Acidosis 7.45
7.8 = death
If full compensation is occurring, pH will be normal
2.Analyze PCO2 & HCO3 to determine if caused by respiratory or metabolic problem (can be both)
Normal PCO2 is 35-45mm Hg arterial
↑ = resp. acidosis ↓= resp. alkalosis
Normal HCO3 is 22-26mEq/L arterial
↑ = metabolic alkalosis ↓ = metabolic acidosis
Define ROME
Respiratory Opposite pH high PCO2 low = alkalosis pH low PCO2 high= acidosis Metabolic Equal pH high HCO3 high= alkalosis pH low HCO3 low= acidosis
