ch 42 potter fluid, electrolyte, acid-base Flashcards
electrolytes such as sodium and potassium and also have a degree of acidity.
Cellular fluids contain
balances within the body maintain the health and function of all body systems.
Fluid, electrolyte, and acid-base
fluid amount (volume), concentration (osmolality), composition (electrolyte concentration), and degree of acidity (pH).
characteristics of body fluids influence body system function because of their effects on cell function
means water that contains dissolved or suspended substances such as glucose, mineral salts, and proteins.
fluid
have less water in their bodies than people who are lean because fat contains less water than muscle
People who are obese
extracellular fluid (ECF)outside the cells and intracellular fluid (ICF)inside the cells
Body fluids are located in two distinct compartments:
is approximately two-thirds of total body water.
adults ICF
approximately one-third of total body water
adults ECF
(intravascular fluid and interstitial fluid)and a minor division (transcellular fluids).
ECF has two major divisions
is the liquid part of the blood (i.e., the plasma)
Intravascular fluid (ECF)
is located between the cells and outside the blood vessels.
Interstitial fluid (ECF)
such as cerebrospinal, pleural, peritoneal, and synovial fluids are secreted by epithelial cells
Transcellular fluid (ECF minor division)
is a compound that separates into ions (charged particles) when it dissolves in water
electrolyte
sodium (Na+), potassium (K+), calcium (Ca2+), and magnesium ions (Mg2+).
Cations in body fluids are
chloride (Cl − ) and bicarbonate (HCO3–)
Anions in body fluids are
salts
Anions and cations combine to make
of a fluid is a measure of the number of particles per kilogram of water.
.Osmolality
fluid with the same tonicity as normal blood is called
isotonic
solution is more dilute than the blood
hypotonics
solution is more concentrated than normal blood
hypertonic
processes that move water and electrolytes between body compartments.
Active transport, diffusion, osmosis, and filtration are
requires energy in the form of adenosine triphosphate (ATP) to move electrolytes across cell membranes against the concentration gradient (from areas of lower concentration to areas of higher concentration).
Active transport
is passive movement of electrolytes or other particles down a concentration gradient (from areas of higher concentration to areas of lower concentration).
-diffusion of electrolytes across cell membranes requires proteins that serve as ion channels.
Diffusion
Water moves across cell membranes by osmosis,a process by which water moves through a membrane that separates fluids with different particle concentrations
osmosis
interstitial fluid from ICF
semipermeable cell membranes separate
, an inward-pulling force caused by particles in the fluid.
osmotic pressure
Fluid moves into and out of capillaries (between the vascular and interstitial compartments) by the process of
filtration
is the net effect of four forces, two that tend to move fluid out of capillaries and small venules and two that tend to move fluid back into them.
Filtration
is the force of the fluid pressing outward against a surface
Hydrostatic pressure
Blood contains albumin and other proteins known as
colloids
Blood colloid osmotic pressure, also called oncotic pressure, is an inward-pulling force caused by blood proteins that helps move fluid from the interstitial area back into capillaries.
oncotic pressure
is strongest at the arterial end of a normal capillary
Capillary hydrostatic pressure
is weaker, and the colloid osmotic pressure of the blood is stronger.
venous end capillary hydrostatic pressure
Disease processes and other factors that alter these forces may cause accumulation of excess fluid in the interstitial space, known
asedema
Inflammation is another
cause of edema
fluid intake and absorption, fluid distribution, and fluid output
Fluid homeostasis is the dynamic interplay of three processes:
is located within the hypothalamus in the brain
thirst-control mechanism
is located within the hypothalamus in the brain
thirst-control mechanism
: the skin, lungs, gastrointestinal (GI) tract, and kidneys.
Fluid output normally occurs through four organs
synthesized by neurons in the hypothalamus that release it from the posterior pituitary gland
ADH
volume imbalances and osmolality imbalances
two major types of fluid imbalances:
means decreased vascular volume
-occurs ECV deficit
hypovolemia
—Water and Sodium Lost or Gained in Equal or Isotonic Proportions
Isotonic Imbalances
—Body Fluids Have Decreased Volume but Normal Osmolality
Extracellular Fluid Volume Deficit
increased osmolality (too concentrated) -water deficit
Hypernatremia
loss of relatively more water than salt or gain of relatively more salt than water
Two general causes make body fluids too concentrated:
are those of cerebral dysfunction, which arise when brain cells shrivel. Hypernatremia may occur in combination with ECV deficit; this combined disorder is called clinical dehydration.
Signs and symptoms of hypernatremia
also called water excess or water intoxication,is a hypotonic condition.
Hyponatremia,
excessively dilute condition of interstitial fluid causes water to enter cells by osmosis, causing the cells to swell
Hyponatremia,
Signs and symptoms of cerebral dysfunction occur when brain cells swell
Hyponatremia,
ECV deficit and hypernatremia often occur at the same time; this combination is called
clinical dehydration
gastroenteritis or other causes of severe vomiting and diarrhea when people are unable to replace their fluid output with enough intake of dilute sodium-containing fluids.
Clinical dehydration is common with
shifts Ca2+out of bone;
Parathyroid hormone
shifts Ca2+into bone.
calcitonin
Electrolyte intake less than electrolyte output or shift of electrolyte from the ECF into cells or bone causes
plasma electrolyte deficit
Electrolyte intake greater than electrolyte output or a shift of electrolytes from cells or bone into the ECF causes
plasma electrolyte excess.
abnormally low potassium concentration in the blood
Hypokalemiais
results from decreased potassium intake and absorption, a shift of potassium from the ECF into cells, and an increased potassium output
Hypokalemiais
diarrhea, repeated vomiting, and use of potassium-wasting diuretics
- muscle weakness
- cardiac dysrhythmias
Common causes of hypokalemia
physiologically active form of calcium in the blood is
ionized calcium.
Factors that cause too much ionized calcium to shift to the bound forms cause symptomatic
ionized hypocalcemia
hypocalcemia because calcium binds to undigested fat in their feces and is excreted.
acute pancreatitis frequently develop
results from increased calcium intake and absorption, shift of calcium from bones into the ECF, and decreased calcium output
Hypercalcemia
abnormally high calcium concentration in the blood.
Hypercalcemiais
(i.e., bone breakage caused by forces that would not break a healthy bone).
pathological fractures
decreases neuromuscular excitability, (lethargic)
Hypercalcemia
increases neuromuscular excitability,
Hypocalcemia
abnormally low magnesium concentration in the blood.
Hypomagnesemiais
decreased magnesium intake and absorption, shift of plasma magnesium to its inactive bound form, and increased magnesium output
Hypomagnesemiais
increases neuromuscular excitability, (similar to hypocalcemia)
Hypomagnesemiais (signs & symp)
abnormally high magnesium concentration in the blood
Hypermagnesemiais
End-stage renal disease causes hypermagnesemia unless the person decreases magnesium intake to match the decreased output
Hypermagnesemiais
decreased neuromuscular excitability, with lethargy and decreased deep tendon reflexes being most common
Hypermagnesemiais (signs and symp)
acid production, acid buffering, and acid excretion
Acid-base homeostasis is the dynamic interplay of three processes:
more H+ions that are present, the
more acidic is a solution.
is 7.35 to 7.45
normal pH range of adult arterial blood
, enzymes within cells do not function properly, hemoglobin does not manage oxygen properly, and serious physiological problems occur, including death
If the pH goes outside the normal range
Laboratory tests of a sample of arterial blood called
arterial blood gases
are used to monitor a patient’s acid-base balance
(ABGs) aka arterial blood gases
is a negative logarithm of the free H+concentration, a measure of the blood’s acidity or alkalinity
pH
is partial pressure of carbon dioxide (CO2), a measure of how well the lungs are excreting CO2 produced by cells.
PaCO2
PaCO2 indicates excessive CO2excretion (less carbonic acid) through
hyperventilation. (PaCO2)
Increased PaCO2indicates CO2accumulation in blood (more carbonic acid) caused by
hypoventilation (PaCO2)
35-45 mm Hg (4.7-6 kPa)
PaCO2
– is concentration of the base (alkaline substance) bicarbonate, a measure of how well the kidneys are excreting metabolic acids.
HCO3
– indicates that the blood has too few metabolic acids;
Increased HCO3
– indicates that the blood has too many metabolic acids.
decreased HCO3
21-28 mEq/L (21-28 mmol/L)
HCO3
80-100 mm Hg (10.7-13.3 kPa)
PaO2
is partial pressure of oxygen (O2), a measure of how well gas exchange is occurring in the alveoli of the lungs
PaO2
is oxygen saturation, the percentage of hemoglobin that is carrying as much O2as possible
SaO2
is observed buffering capacity minus the normal buffering capacity, a measure of how well the blood buffers are managing metabolic acids.
Base excess
carbonic acid and metabolic acids
Cellular metabolism constantly creates two types of acids:
are any acids that are not carbonic acid. They include citric acid, lactic acid, and many others.
Metabolic acids
are pairs of chemicals that work together to maintain normal pH of body fluids
Buffers
bicarbonate (HCO3–) buffer system, which buffers metabolic acids
The major buffer in the ECF is the
lungs and kidneys
body has two acid-excretion systems:
carbonic acid
lungs excrete
metabolic acids
the kidneys excrete
describes a condition that tends to make the blood relatively too acidic
acidosis
respiratory acidosis and metabolic acidosis.
cells produce two types of acid, there are two different types of acidosis:
describes a condition that tends to make the blood relatively too basic (alkaline)
alkalosis
respiratory alkalosis and metabolic alkalosis
two types of alkalosis:
arises from alveolar hypoventilation; the lungs are unable to excrete enough CO2
Respiratory acidosis
—Excessive Carbonic Acid Caused by Alveolar Hypoventilation
Respiratory Acidosis
bicarbonate
base
cause the removal of HCO3–, the amount of HCO3– in the blood decreases.= identyfying specific cause HCP and laboratory calculate
anion gap
,a reflection of unmeasured anions in plasma
anion gap
who are between the ages of 2 and 12 frequently respond to illnesses with fevers of higher temperatures and longer duration than those of adults
Children
have increased metabolism and water production because of their rapid growth changes
Adolescents
normal aging, various disease conditions, and multiple medications
Older adults experience a number of age-related changes that potentially affect fluid, electrolyte, and acid-base balances
is a hypotonic sodium-containing fluid.
Sweat
Starvation diets or those with high fat and no carbohydrate content often
lead to metabolic acidosis
hypomagnesemia, in part because it increases renal magnesium excretion
Chronic alcohol abuse commonly causes
as an antacid, which can cause ECV excess because of its high sodium content that holds water in the extracellular compartments
baking soda
in which excess secretion of ADH causes hyponatremia by retaining too much water and concentrating the urine
syndrome of inappropriate antidiuretic hormone (SIADH), // occur in head injury
In many institutions AP record oral intake but not intake through feeding or IV tubes, which are nursing responsibilities. Similarly AP often record urine, diarrhea, and vomitus output but not drainage through tubes.
-You or the AP calculates the 24-hour totals (see agency policy).
I&O delegation to AP
when a patient has a mechanical obstruction of the GI tract, severe nausea, is at high risk for aspiration, or has impaired swallowing.
Oral replacement of fluids is contraindicated
by mouth in a patient with ECV deficit, choose fluids that contain sodium
(e.g., Pedialyte and Gastrolyte)
Liquids that contain lactose or have low-sodium content are
inappropriate when a patient has diarrhea.
1 oz (30 mL) of liquid.
fluid restriction can swallow a number of pills with as little as
parenteral nutrition (PN), IV fluid and electrolyte therapy (crystalloids), and blood and blood component (colloids) administration
Parenteral replacement includes
IV devices are called
when the catheter tip lies in a vein in one of the extremities;
peripheral IVs
when the catheter tip lies in the central circulatory system
-ex: (e.g., in the vena cava close to the right atrium of the heart)
central venous catheters (CVCs) or IVs
Parenteral nutrition (PN), also called -IV administration of a complex, highly concentrated solution containing nutrients and electrolytes that is formulated to meet a patient’s needs.
total PN (TPN)
isotonic, hypotonic, or hypertonic
IV solution is
have the same effective osmolality as body fluids. Sodium-containing isotonic solutions such as normal saline are indicated for ECV replacement to prevent or treat ECV deficit.
Isotonic solutions (IV solution)
have an effective osmolality less than body fluids, thus decreasing osmolality by diluting body fluids and moving water into cells.
Hypotonic solutions
have an effective osmolality greater than body fluids. If they are hypertonic sodium-containing solutions, they increase osmolality rapidly and pull water out of cells, causing them to shrivel
Hypertonic solutions
are catheters or infusion ports designed for repeated access to the vascular system.
Vascular access devices (VADs)
are for short-term use (e.g., fluid restoration after surgery and short-term antibiotic administration).
Peripheral catheters
, which empty into a central (catheter tip) vein
long-term use include central catheters and implanted ports
for administering large volumes of fluid, PN, and medications or fluids that irritate veins.
Central lines are more effective than peripheral catheters
bundle: hand hygiene; maximum sterile barrier precautions; chlorhexidine skin antisepsis using chlorhexidine (>0.5%) in alcohol; avoidance of the femoral vein for central venous access for adults; and placement under planned controlled conditions.
prevent CLABSI//Central Line–Associated Bloodstream Infections
VADs; tourniquet; clean gloves; dressings; IV fluid containers; various types of tubing; and electronic infusion devices (EIDs), also calledinfusion pumps
IV equipment includes
electronic infusion devices (EIDs), also called
infusion pumps
; it consists of a small plastic tube or catheter threaded over a sharp stylet (needle)
VAD is called an over-the-needle catheter
main IV fluid used in a continuous infusion flows through tubing called the
primary line.
is a technique in which a vein is punctured through the skin by a sharp rigid stylet (e.g., metal needle).
Venipuncture
are to collect a blood specimen, start an IV infusion, provide vascular access for later use, instill a medication, or inject a radiopaque or other tracer for special diagnostic examinations.
purposes of venipuncture
physiological compromise in a patient who is dehydrated, in circulatory shock, or critically ill.
An infusion rate that is too slow often leads to further
causing fluid and electrolyte imbalances and cardiac complications in vulnerable patients (e.g., older adults or patients with preexisting heart disease).
An infusion rate that is too rapid overloads the patient with IV fluid,
, also called IV pumps or infusion pumps
Electronic infusion devices (EIDs)
are used occasionally with an IV solution infused by gravity to prevent accidental infusion of a large fluid volume
Nonelectronic volume-control devices
, the height of the container influences flow rate.
For gravity flow
(1) keeping the system sterile and intact; (2) changing IV fluid containers, tubing, and contaminated site dressings; (3) helping a patient with self-care activities so as not to disrupt the system; and (4) monitoring for complications of IV therapy
Line maintenance involves
Protective devices designed to prevent movement or accidental dislodgment of a VAD are called
catheter stabilization device
no more frequentlythan every 96
-specify tubing changes every 4 hours for blood
continuous infusion tubing changes occur
every 24 hours because of the increased risk of contamination from opening the IV system
-blood components and every 24 hours for continuous IV lipids.
intermittent infusion changes occur
occurs when an IV catheter becomes dislodged or a vein ruptures and IV fluids inadvertently enter subcutaneous tissue around the venipuncture site
Infiltration
IV fluid contains additives that damage tissue, ex chemotherapy
extravasation
(i.e., inflammation of a vein) results from chemical, mechanical, or bacterial causes.
Phlebitis
include acidic or hypertonic IV solutions; rapid IV rate; IV drugs such as KCl, vancomycin, and penicillin; VAD inserted in area of flexion; poorly secured catheter; poor hand hygiene; and lack of aseptic technique.
Risk factors for phlebitis
air is present inside syringes, IV tubing is not primed with fluid, or connectors are not removed before use and cause air to enter a patient’s vein. It also can occur if the VAD is not clamped before changing the tubing or if the IV tubing is punctured inadvertently
Air embolism occurs when
is the IV administration of whole blood or a blood component such as packed red blood cells (RBCs), platelets, or plasma.
Blood transfusion, or blood component therapy,
(1) increasing circulating blood volume after surgery, trauma, or hemorrhage; (2) increasing the number of RBCs and maintaining hemoglobin levels in patients with severe anemia; and (3) providing selected cellular components as replacement therapy (e.g., clotting factors, platelets, albumin).
Objectives for administering blood transfusions include
are considered universal blood donors because they can donate packed RBCs and platelets to people with any ABO blood type.
O-negative blood
called universal blood recipients because they can receive packed RBCs and platelets of any ABO type.
AB-positive blood are
, which refers to another antigen in RBC membranes.
Rh factor
is the collection and reinfusion of a patient’s own blood
Autologous transfusion(autotransfusion)
(1) that blood components delivered are the ones that were ordered, (2) that blood delivered to a patient is compatible with the blood type listed in the medical record, and (3) that the right patient receives the blood.
patient safety always verify three things:
reveals acid-base status and the adequacy of ventilation and oxygenation
ABG analysis
