Fundametals Of Nursing: Fluid, Electrolyte, And Acid–Base Balance

Front 1

Describe intracellular fluid (ICF)

Back 1

ICF is the fluid within cells 40% of the adult's body weight.

Front 2

Describe Extracellular fluid (ECF)

Back 2

The fluid outside the cells 20% of the body weight. 75% interstitial fluids & 25% intravascular (plasma)

Front 3

List the major homeostatic mechanisms in fluid balance

Back 3

Skin: perspiration

Lungs: regulate O2 & CO2 of the blood; crucial in maintaining acid–base balance

Kidneys: selectively retain electrolytes, water, excrete wastes & excesses, acid base balance

GI: water and nutrients that enter the body through this route

Front 4

Describe the Hormonal control of fluid balance

Back 4

Antiduretic hormone:

Front 5

Active passport

Back 5

Requires the cell to spend energy, usually in the form of ATP. Examples include transport of large molecules (non-lipid soluble) and the sodium-potassium pump

Front 6

Diffusion

Back 6

Diffusion is the net movement of a substance (liquid or gas) from an area of higher concentration to one of lower concentration.

Front 7

Filtration

Back 7

Filtration is the passage of fluid through a permeable membrane. Passage is from an area of high pressure to one of lower pressure.

Front 8

Osmosis

Back 8

Diffusion of water molecules across a membrane in response to differences in solute concentration. Water moves from areas of high-water/low-solute concentration to areas of low-water/high-solute concentration. Diffusion of water across a semi-permeable barrier such as a cell membrane, from high water potential (concentration) to lower water potential (concentration).

Front 9

Hypertonic solutions

Back 9

Are those in which more solute (and hence lower water potential) is present

Front 10

Hypertonic solutions

Back 10

A solution having a high concentration of solute.

Front 11

Isotonic solutions

Back 11

Have equal (iso-) concentrations of substances. Water potentials are thus equal, although there will still be equal amounts of water movement in and out of the cell, the net flow is zero.

Front 12

Hypervolemia

Back 12

Excessive retention of water and sodium in ECF in near-equal proportions results in a condition termed fluid volume excess

Front 13

Signs and symptoms of Hypervolemia

Back 13

Bounding pulse, elevated BP, respiratory changes, edema, weight gain, increased urine output, heart failure.

Front 14

Nursing interventions for hypervolemia

Back 14

Monitor I & O, weight
place in a fowler's position. O2, restrict fluids & sodium.

Front 15

Define electrolytes

Back 15

Substances capable of breaking into electrically charged ions when dissolved in a solution

Front 16

Sodium (Na+):

Back 16

Chief electrolyte of ECF influential in many chemical reactions particularly in nervous & muscle tissue cells.
Controls & regulates the volume of body fluids
Maintains water balance throughout the body
Is the primary regulator of ECF volume

Front 17

Sources and Losses Sodium (Na+):

Back 17

2,400 mg (approx. 1 tsp) Sodium found in many foods; typically present in large amounts, particularly in processed foods.

Eliminated primarily by the kidneys; small amounts lost in feces and perspiration

Front 18

Hyponatremia

Back 18

Na+2 Less than 135mEq/L

Sodium deficit in ECF caused by a loss of sodium or a gain of water. Due to the decrease in sodium, fluid moves by osmosis from the less concentrated ECF compartment to the ICF space. This shift of fluid can lead to swelling of the cells and cerebral edema. Seizures and permanent neurological damage can result from severe hyponatremia

Front 19

Cuases of Hyponatremia

Back 19

NPO, excessive diaphoresis, diuretics, GI suction, fresh water near drowning, decreased aldasterone, fluid overload

Front 20

Signs and symptoms of Hyponatremia

Back 20

Na+2 levels less than; 135mEq/L
Fluid excess or deficit, mental status changes, weakness & vomiting

Front 21

Nursing interventions for hyponatremia:

Back 21

Monitor I & O, weight, restrict fluids, admister diuretics/steroids

Front 22

Hypernatremia

Back 22

Na+2 greater than 145mEq/L

Hypernatremia refers to a surplus of sodium in ECF that can result from excess water loss or an overall excess of sodium. Because of the increased extracellular osmotic pressure, fluids move from the cells, causing them to shrink and leaving them without sufficient fluid. The cells of the central nervous system are especially affected, and signs of neurological impairment may result from severe hypernatremia.

Front 23

Causes of Hypernatremia

Back 23

Renal failure, excssive intake of sodium, dehydration, acute/chronic illness, IV fluids

Front 24

Signs and symptoms of Hypernatremia

Back 24

Sodium levels greater than 145mEq/L, thirst, mentatl status changes, seizures, muscle weakness, respiratory compromise

Front 25

Nursing interventions for hypernatremia:

Back 25

Treat fluid imbalance 1st, monitor I & O, weight, administer diuretics, restrict sodium, dialysis, treat cause.

Front 26

Potassium (K+):

Back 26

Major cation of ICF working in reciprocal fashion with sodium (eg, an excessive intake of sodium resulting in an excretion of potassium, and vice versa)chief regulator of cellular enzyme activity and cellular water content
Plays a vital role in such processes as the transmission of electric impulses, particularly in nerve, heart, skeletal, intestinal, and lung tissue; protein and carbohydrate metabolism; and cellular building
Assists in regulation of acid-base balance by cellular exchange with H+

Front 27

Sources and Losses of Potassium (K+):

Back 27

50 to 100 mEq daily
Leading food sources: bananas, peaches, melons, potatoes.

Potassium excreted primarily by the kidneys (no effective method of conserving potassium); deficits occur if potassium excretion in excess without being replaced simultaneously.

Gastrointestinal (GI) secretions contain potassium in large quantities; also some in perspiration and saliva

Front 28

Hypokalemia:

Back 28

K+ less than 3.5mEq/L

When the extracellular potassium level falls, potassium moves from the cell, creating an intracellular potassium deficiency. Sodium and hydrogen ions are then retained by the cells to maintain isotonic fluids. These electrolyte shifts influence normal cellular functioning, the pH of ECF, and the functions of most body systems, including the cardiovascular system. Skeletal muscles are generally the first to demonstrate a potassium deficiency.

Front 29

Causes of Hypokalemia:

Back 29

Severe loss of GI fluids; NG suction. gastric lavage, prolonged vomiting diarrhea, diaphoresis, diuresis, drugs; diuretics, steroids, insulin

Front 30

Signs and symptoms of Hypokalemia:

Back 30

K+ levels bellow 3.5mEq/L, muscle weakness, shallow respirations, mental status changes, weak irregular pulse, ECg changes, cramping, N/V, respiatory arrest

Front 31

Nursing interventions for Hypokalemia:

Back 31

Treat cuase, offer potassium rich foods/replacement, educate pt.

Front 32

Hyperkalemia

Back 32

Refers to an excess of potassium in ECF. Although this condition occurs less frequently than hypokalemia, it can be hazardous. Nerve conduction as well as muscle contractility can be affected. A variety of cardiac irregularities may result, including cardiac arrest if hyperkalemia is not corrected.

Front 33

Causes of Hyperkalemia:

Back 33

Overuse of potassium based salt substitute/potassium supplements, potasium sparing diretics, renal failure, massive tissue truma, metabolic acidosis

Front 34

Signs and symptoms of Hyperkalemia:

Back 34

k+ level above 5mEq/L, muscle twiching, cramps, diarrhea, low BP, cardiac dysrhythmia & arrest

Front 35

Nursing Interventions for hyperkalemia:

Back 35

Limit potassium intake, administer medications as ordered

Front 36

Hypocalcemia

Back 36

Refers to a calcium deficit in ECF.

Front 37

Signs and symptoms of hypocalcemia

Back 37

Common signs of hypocalcemia include numbness and tingling of fingers, muscle cramps, and tetany.

Front 38

Causes of Hypocalcemia

Back 38

Common causes related to a calcium deficit involve inadequate calcium intake, impaired calcium absorption, and excessive calcium loss.

Front 39

Hypercalcemia

Back 39

Refers to an excess of calcium in ECF.

Front 40

Signs and symptoms of Hypercalcemia

Back 40

Hypercalcemia is an emergency situation because the condition often leads to cardiac arrest.

Front 41

Causes of Hypercalcemia

Back 41

Ca+ levels above 5.5 mEq/L
Two major causes of hypercalcemia are cancer and hyperparathyroidism.

Front 42

Respiratory Acidosis

Back 42

Excess buildup of CO2 in the blood, occurs secondary to problems that cause hypoventalation:
CNS deoression, airwway resistance, loss of lung resistance, neuromuscular disease, mechanical ventalation.

Front 43

Signs and symptoms of respiratory acidosis:

Back 43

pH: Less than 7.35
pCO2: More than 45
Dyspnea, hypoxia, restlessness, drowsiness, dizziness, tachycardia & tachypnea, diaohoresis, seizures

Front 44

Nursing interventions of respiratory acidosis:

Back 44

Administration of bronchodialtors, semi fowlers position, assess airway, monitor for less than 12 breaths per minute.

Front 45

Repiratory alkalosis:

Back 45

Low circulating CO2 levels in the blood from hyperventalation secondary to hypoxia, pulmonary emboli, pain, anxiety

Front 46

Signs and symptoms of Repiratory alkalosis:

Back 46

pH: greater than 7.45
pCO2: less than 35
HYPERVENTALATION, dizziness, anxiety, epigastric pain, tetany, seziures

Front 47

Nursing interventions of respiratory alkalosis:

Back 47

Monitor: rspiratory rate/depth, encourage rebreathing, try to relax, reduce stimuli

Front 48

Metabolic acidosis:

Back 48

Exess production of acid or rapid excretion of HCO3. Mtabolic system primary problem, respiratory system atempts to compensate

Front 49

Signs and symptoms of Metabolic acidosis:

Back 49

pH:less than 7.35
HCO3: Less than 22
CO2: may be normal
Kassmaul breathing (deep, rapid respirations), Confusion, headache, lethargy, arrythmia, hot flushed skin, abdominal pain

Front 50

List the three major homeostatic regulators of hydrogen ions.

Back 50

(1) buffer systems, (2) respiratory mechanisms, and (3) renal mechanisms

Front 51

Define buffer

Back 51

A buffer is a substance that prevents body fluids from becoming overly acidic or alkaline.

Front 52

What are the body's three buffer systems:

Back 52

(1) the carbonic acid–sodium bicarbonate buffer system, (2) the phosphate buffer system, and (3) the protein buffer system

Front 53

Respiratory Control of H+ Balance

Back 53

The lungs are the primary controller of the body's carbonic acid supply. Due to the huge surface area from which CO2 can readily diffuse, the lungs can bring about rapid changes in H+ when needed. Carbon dioxide, constantly produced by cellular metabolism (carbonic acid [H2CO3] yields CO2 and H2O), is excreted by exhalation

Short term/rapid response

Front 54

Renal Control of H+ Balance/Bicarbonate Formation

Back 54

the kidneys excrete or retain hydrogen ions and form or excrete bicarbonate ions in response to the pH of the blood. In the presence of acidosis, the kidneys excrete hydrogen ions and form and conserve bicarbonate ions, thus raising the pH to the normal range. If alkalosis is present, the kidneys retain hydrogen ions and excrete bicarbonate ions in an effort to return to a balanced state.
Acid–base regulation by the kidneys occurs more slowly than that which occurs by the carbonic acid–sodium bicarbonate system or by respiratory regulation

Front 55

Third-space fluid shift

Back 55

refers to a distributional shift of body fluids into potential body spaces such as the pleural,
P.1684
peritoneal (ascites), or pericardial areas; joint cavities; the bowel; or interstitial spaces. The fluid moves out of the intravascular spaces (plasma) to any of these spaces. Once trapped in these spaces, the fluid is not easily exchanged with ECF

Front 56

Respiratory acidosis:

Back 56

↓ pH < 7.35 ↑ PaCO Normal HCO3-

Front 57

Respiratory alkalosis:

Back 57

↑ pH > 7.45 ↓ PaCO2 Normal HCO3-

Front 58

Metabolic acidosis:

Back 58

↓ pH < 7.35 ↑ HCO3-Normal PaCO2

Front 59

Metabolic alkalosis:

Back 59

↑ pH > 7.45 ↓ HCO3-Normal PaCO2

Front 60

When interpreting ABGs, follow these necessary steps:

Back 60

1. Determine whether the pH is alkalotic or acidotic.

2. Check for the cause of the change in pH. Is it respiratory (PaCO2) or metabolic (HCO3-)? In respiratory acid–base imbalances, the pH and PaCO2 values are inversely abnormal (move in opposite directions):

3. Determine whether the body is compensating for the pH change. When the problem is respiratory, the renal system assists in compensation either by increasing or by decreasing HCO3-. In contrast, the respiratory system assists in compensating for a metabolic acid–base imbalance by regulating CO2 levels. When compensation occurs, the PaCO2 and the HCO3-will always point in the same direction. The focus of compensation efforts is to return the pH to the normal range:

Front 61

Compensation is classified as Absent if:

Back 61

pH abnormal
One component abnormal
Second component within normal range

Front 62

Compensation is classified as Partial if:

Back 62

pH abnormal
One component abnormal
Second component beginning to change

Front 63

Compensation is classified as Complete if:

Back 63

pH within normal range
One component abnormal
Second changed to move pH within normal range

Front 64

When assessment data point to fluid and electrolyte problems amenable to nursing therapy, they receive one of three diagnostic labels:

Back 64

Excess Fluid Volume
Deficient Fluid Volume
Risk for Imbalanced Fluid Volume

Front 65

Outcome Identification and Planning in Fluid and Electrolyte Disturbances

Back 65

Maintain an approximate balance between fluid intake and fluid output (average about 2500 mL fluid intake and output over 3 days)

Maintain a urine specific gravity within normal range (1.010–1.025)

Practice self-care behaviors to promote fluid, electrolyte, & acid–base balance

Identify signs and symptoms of recurrence of imbalance with need to notify the physician