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NUR 201 Week 6 > Fluids & Electrolytes Pt 1 > Flashcards

Fluids & Electrolytes Pt 1 Flashcards

1
Q

Homeostasis

  • State of equilibrium in body
  • Naturally maintained by adaptive responses
  • Body fluids and electrolytes are maintained within narrow limits
A

Water Content of the Body

  • 50-60% of body weight in adult
    > Greater in men than women as men have more lean body mass
  • 45-55% in older adults
  • 70-80% in infants
    > Varies w/gender, body mass, & age
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2
Q

Compartments

  • Intracellular fluid (ICF) [2/3 body water]
A

Extracellular fluid (ECF) [1/3 body water]

  • Intravascular (plasma) [1/3 of ECF]
  • Interstitial [2/3 of ECF]

> Transcellular
- CSF, fluid in GI tract, pleural, synovial, peritoneal, intraocular, pericardial

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3
Q

Fluid Compartments of the Body

  • ICF (40%)
  • ECF (20%) [intravascular & interstitial]
  • Solids (40%)
A

! Water is the key to the proper transport & delivery of nutrients, electrolytes, & other substances to organs, tissues, & cells
Therefore, if you have changes in the amounts of water and/or electrolytes, it can affect ALL of the functioning of the cells, organs, & tissues

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4
Q

Electrolyte Composition

ICF

Prevalent cation is ?

Prevalent anion is ?

A

K+

PO3-4 (phosphate)

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5
Q

ECF

Prevalent cation is ?

Prevalent anion is ?

A

Na+

Cl-

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6
Q

Mechanisms Controlling Fluid & Electrolyte Movement

  • Filtration
  • Diffusion/facilitated diffusion
  • Osmosis
A
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7
Q

?

Is the movement of fluid through a cell or blood vessel membrane b/c of hydrostatic pressure differences on both sides of the membrane

If nothing stops it, water can move from a higher hydrostatic pressure space to a lower one

A

Filtration

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8
Q

?

Is reached when enough fluid leaves one space & enters the other until the hydrostatic pressure is equal

A

Equilibrium

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9
Q

?

Is the movement of molecules from high to low concentration

Liquids, solids, & gases; membrane separating 2 areas must be permeable to diffusing substance; requires no energy

Gases (O2, N, CO2) & other substances (i.e., urea) can permeate through cell membranes & are distributed throughout body

A

Diffusion

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10
Q
  • Differences in concentrations and/or permeability allow or prevent these shifts
  • i.e., Na+ often times has to cross an impermeable membrane & needs the Na+ pump & energy provided by ATP
A
  • Can be facilitated diffusion, like w/glucose, needs assistance of insulin to cross

! Diffusion is important in the transport of most electrolytes & particles throughout cell membrane

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11
Q

Na+ K+ Pump

By active transport, Na+ moves out of the cell & K+ moves into the cell to maintain concentration difference

A
  • Energy for this mechanism is ATP, made in cell’s mitochondria
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12
Q

?

Movement of H2O between 2 compartments by a membrane permeable to H2O but not to solute

  • Moves from low to high concentration
  • Requires no energy
A

Osmosis

  • Stops when the concentration differences disappear, or when hydrostatic pressure builds and is sufficient to oppose any further movement of water
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13
Q
  • The thirst mechanism is an example of how osmosis helps maintain homeostasis
  • Feeling of thirst is caused by activation of cells in the brain that respond to changes in ECF osmolarity
A
  • A rising blood osmolarity, or a decreasing blood volume triggers the sensation of thirst
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14
Q

Filtration: Clinical Significance: Blood Pressure

  • BP is an example of hydrostatic filtering forces; moves whole blood from the heart to capillaries where filtration can occur to exchange water, nutrients, and waste products between blood & tissues
A

Clinical Significance: Edema

  • Edema develops w/changes in normal hydrostatic pressure differences; occurs when the pressure gradients aren’t balanced & fluid ends up in the interstitial spaces

> i.e., Rt-sided HF

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15
Q

Effects of Water Status on RBC

  • If a cell is surrounded by hypotonic fluid, water moves into the cell, causing it to swell & possibly to burst
A
  • If a cell is surrounded by hypertonic fluid, water leaves the cell to dilute the ECF; the cell shrinks & eventually may die
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16
Q

Fluid Balance

  • Fluid intake
  • Fluid loss - minimum amount of urine needed to excrete toxic waste products is 400-600 mL; insensible water loss
A
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17
Q

?

Is the invisible vaporization from the lungs and skin that helps regulate body temperature; 600-900 mL/day

A

Insensible water loss

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18
Q
  • Accelerated body metabolism that occurs with increased body temp & exercise increases the amt of water loss; insensible perspiration causes only water loss
A
  • Excessive sweating (sensible perspiration) caused by exercise, fever, or high environmental temperatures may lead to large losses of water & electrolytes
19
Q

?

Is an abnormal accumulation of interstitial fluid (i.e., edema)

A

Second spacing

20
Q

?

Is a normal distribution of fluid in ICF and ECF

A

First spacing

21
Q

?

Is fluid accumulation in part of body where it is not easily exchanged w/ECF (i.e., ascites, sequestration of fluid in abdominal cavity w/peritonitis, & edema assoc w/burns, trauma, or sepsis)

A

Third spacing

22
Q

Hormonal Regulation of BP

  • Aldosterone
  • ADH
  • Natriuretic peptides
A
23
Q

?

Is secreted by the adrenal cortex & regulates sodium & water reabsorption by the kidneys

A

Aldosterone

24
Q

?

Is produced by the hypothalamus to reduce diuresis & increase water retention if serum osmolarity inc or if blood volume dec

A

ADH (aka, vasopressin)

25
Q

?

These hormones are secreted in response to increased blood volume & BP

They then bind to the receptor sites in nephrons of the kidney that create effects that are OPPOSITE to aldosterone; this then dec the BP by causing vasodilation & reduces fluid volume by inc excretion of sodium & water

A

Natriuretic peptides

i.e., ANP [atrial], BNP [brain]

! This is why 1 of the tests for HF is elevated BNP

26
Q

Regulation of Water Balance

  • Hypothalamic-pituitary regulation
    > Osmoreceptors in hypothalamus sense fluid deficit or increase
    > Deficit stimulates thirst & ADH release
    > Decreased plasma osmolality (water excess) suppresses ADH release
A
27
Q
  • Renal regulation
    > Primary organs for regulating fluid & electrolyte balance

> Adjusting urine volume
- Selective reabsorption of water & electrolytes
- Renal tubules are sites of action of ADH & aldosterone

A
28
Q
  • Adrenal cortical regulation
    > Releases hormones to regulate water & electrolytes

> Glucocorticoids
- Cortisol

> Mineralocorticoids
- Aldosterone

A
29
Q

Glucocorticoids primarily have an anti-inflammatory effect & increase serum glucose levels

A

Mineralocorticoids cause sodium retention & potassium excretion; water is retained w/sodium

30
Q

Decreased renal perfusion or decreased sodium delivery to the distal portion of the renal tubule activates the ____, which results in aldosterone secretion

A

renin-angiotensin-aldosterone system (RAAS)

31
Q

Increased serum potassium, decreased serum sodium, & release of ACTH from anterior pituitary also stimulate release of aldosterone

A
32
Q
  • Gastrointestinal regulation
  • Oral intake accounts for most water
  • Small amounts of water are eliminated by GI tract in feces
  • Diarrhea & vomiting can lead to significant fluid & electrolyte loss
A
33
Q

Gerontologic Considerations

  • Structural changes to kidneys decrease ability to conserve water
  • Hormonal changes lead to decrease in renin & aldosterone and increase in ADH & ANP
  • Loss of subcutaneous tissue leads to increased loss of moisture
A
  • Reduced thirst mechanism results in decreased fluid intake
  • Functional changes affect ability to independently obtain fluids
  • Nurse must assess for these changes & implement treatment accordingly
34
Q

Fluid & Electrolyte Imbalances

  • Directly caused by illness or disease (burns or HF)
  • Result of therapeutic measures (IV fluid replacement or diuretics)
A
  • Imbalances as deficits or excesses
  • i.e., a pt w/prolonged NG suction will lose Na+, K+, H+, & Cl-
    > Imbalances may result in a deficiency of both Na+ & K+, a fluid volume deficit, & a metabolic alkalosis resulting from loss of HCl

! Restoring fluid balance & preventing injury

35
Q

ECF volume deficit ( ? )

A

hypovolemia

36
Q
  • Abnormal loss of normal body fluids, inadequate intake, or plasma-to-interstitial fluid shift
  • Vomiting, diarrhea, fistula drainage, hemorrhage, diuresis; also 2nd to dz process like diabetes insipidus, burns, hemorrhage, & intestinal obstruction
A

! Do not use interchangeably w/dehydration as dehydration refers to loss of pure water alone w/o corresponding loss of sodium

37
Q
  • Clinical manifestations r/t loss of vascular volume as well as CNS effects
  • Restlessness, drowsiness, lethargy, confusion, postural hypotension, tachycardia, tachypnea, weakness, dizziness, wt loss, seizures, coma
  • Skin turgor, capillary refill, & urine output dec’d
A
  • Treatment: replace water & electrolytes w/balanced IV solutions
  • LR, isotonic (0.9%) NaCl, blood
38
Q

ECF volume excess ( ? )

A

hypervolemia

39
Q
  • Excessive intake of fluids, abnormal retention of fluids (HF, renal failure), or interstitial-to-plasma fluid shift (inc intravascular volume)
A
  • Clinical manifestations r/t excess volume
  • HA, confusion, lethargy, peripheral edema, JVD, bounding pulse, HTN, dyspnea, crackles, pulmonary edema, muscle spasms, wt gain, seizures, coma
40
Q
  • Treatment: remove fluid w/o changing electrolyte composition or osmolality of ECF
  • Diuretics & fluid restriction
A
41
Q

?

  • Excess fluid volume (r/t inc water &/or sodium retention)
  • Impaired gas exchange (r/t water retention leading to pulmonary edema)
  • Risk for impaired skin integrity (b/c peripheral edema)
  • Activity intolerance (b/c inc water retention, fatigue, & weakness)
  • Disturbed body image (d/t appearance of edema)
  • Potential complications: pulmonary edema, ascites
A

Hypervolemia

42
Q

?

  • Deficient fluid volume & Decreased CO (r/t excessive ECF losses or dec fluid intake)
  • Risk for deficient fluid volume
  • Potential complication: hypovolemic shock (if fluid loss continues w/o replacement)
A

Hypovolemia

43
Q

Generate Solutions & Take Action

  • I&O
  • Monitor cardiovascular changes (changes in BP, pulse force, JVD)
  • Assess respiratory status
    > Excess = pulm congestion/edema, SOB, moist crackles
    > Deficit = inc RR
  • Neurologic changes, skin assessment
A
  • Specific gravity <1.005 = FLUID OVERLOAD
  • Water = ~1.000
  • Ideal = 1.002 - 1.030

> The higher the # the more dehydrated you might be

  • Closer the # is to 1.000, greater the FLUID EXCESS
44
Q

Assessment of Skin Turgor

  • Usual eval sites = over sternum, abdomen, & anterior forearm
A

! Dec skin turgor is less predictive of fluid deficit in older persons b/c loss of tissue elasticity

NUR 201 Week 6 (5 decks)

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