FLUIDS & ELECTROLYTES

Human Body is a complex machine that contains hundreds of bones AND the most sophisticated systems of any structure on earth.

YET…the substance that is basic to the very existence of the body is the simplest substance known

Functions

aid in removal of cellular waste

facilitate transport of nutrients, hormones, proteins, other molecules into cells

The particles can move into and out of the body only because of

WATER

H20 & electrolytes make up 1/2 to 2/3 of an average adult’s body weight!!!

2/3 (60%) of total body fld exists in the intracellular space (primarily in muscles)

1/3 (40%) primarily found in the extracellular space (between cells and in plasma)

body fat content

gender

age

Fat cells contain little water

Obese individuals, in general, have considerably less fluid than those of lean build

Women have proportionately less body fluid than men, because they have proportionately more body fat

Elderly have less body fld than younger adults b/o more fat than lean muscle mass

ECF is more easily lost…..fvd a major concern

Infants have a high body fluid content (approx 70% - 80% of their body weight)

In addition, infants have 50% of body fld in ECF

ECF is more easily lost…..fvd a major concern

The body fluid contains:

nonelectrolytes: substances such as glucose, urea, creatinine, bilirubin, etc.

-measured in mg

electrolytes: substances that dissociate (separate) in solution & will conduct an electric current

-measured in milliequivalents (mEq)

Anion--electrolytes that develop negative charge when dissolved in water

Cation--electrolytes that develop positive charge when dissolved in water

Lab values of electrolytes is a reflection of the extracellular (intravascular & interstitial spaces)

Lab values do not necessarily reflect the electrolyte composition of the intracellular fluid

Osmosis

Diffusion

Filtration

Sodium Potassium Pump

active transport……keeps electrolytes inside and outside the cell in their "uneven" balance

The measure of a solution's ability to create osmotic pressure and thus affect the movement of water

May also be described as the ratio of solutes to water

Another term to describe the concentration of solutions

Reflects the number of particles in a liter of solution

The difference between osmolality and osmolarity is small…….and the terms are often used interchangeably

A reflection of osmolality

Isotonic--osmolality same as body fluids…..e.g., 0.9% NACL

Hypotonic--osmolality < body fluids….e.g., 0.45% NACL

Hypertonic--osmolality > body fluids….e.g., 3% NACL

drinking

eating

IV fluids

subcutaneous import

gastric/enteral feedings

average daily loss (adult) approx 2600 ml

kidneys (urine)

GI tract (stool)

lungs

Routes of F&E Losses (cont’d)

skin (perspiration, evaporation)

third spacing

Regulate pH (acid bas balance) of ECF by excretion or retention of hydrogen ions

Excretion of wastes & toxic substances

Secretes renin….stimulates aldosterone release

Pumping action of heart perfuses kidneys

Pumping provides circulation of all blood to the kidneys so urine can be formed to rid body of wastes

Eliminates hydrogen (pH)

Eliminates CO2 (a potential acid) (pH)

Eliminate water

As ADH secretion increases…H20 retention increases

As ADH secretion decreases….H20 loss increases

Osmolality & ADH are normally in constant interaction

A rising osmolality (e.g., incr salt intake) increases ADH secretion & thus increases retention of H20

A falling osmolality (e.g., incr H20 intake) decreases ADH secretion & enhances water excretion

Adrenal Cortex

produces aldosterone-----acts on the distal tubule of the kidney to promote NA+ reabsorption in exchange for K+ and H+ ions which are excreted

Regulate CA+ and Phosphate balance

Results most commonly when water and electrolytes are lost in an isotonic fashion

Not to be confused with "dehydration" which refers to loss of water alone (leaving the pt with sodium excess)

Hypertonic fvd --- greater proportion of fluid is lost compared with solute loss

Hypotonic fvd --- greater proportion of solute is lost compared with fluid loss

Depletion of ECF volume is termed hypovolemia

Body’s fluid level in NOT sufficient to meet the body’s fluid needs

Depending on the type of fluid lost, hypovolemia may be accompanied by acid-base, osmolar, and/or electrolyte imbalances

Causes:

-excessive fluid losses

-insufficient fluid intake

-combination of both

GI tract disorders

Renal disorders

Endocrine disorders

Hemorrhage

Burns

Medications

Fever

Wound Drainage

GI suction

Excessive Sweating

Third Spacing

Excessive Laxative/Enema Use

Hyperventilation

Lack of access to fluids

Inability to request fluids

Inability to swallow fluids

Altered thirst mechanisms

Nausea, anorexia

Extracellular space fluid is 1st affected

Interstitial fld goes into the intravascular space to attempt to maintain fld vol for tissue/organ perfusion

As the interstitial fld is depleted, its’ fld becomes hypertonic

Cellular fld is drawn in to the interestitial space, leaving cells with less than adequate fluid to function properly

Intravascular volume (blood flow) is decreased thru the kidneys

This sends a signal to the posterior pituitary to secrete ADH to stimulate fluid retention by the kidneys

Renin is secreted by the kidneys to stimulate adrenal cortex to release aldosterone

As fld is retained, intravascular & eventually interstitial volume is increased

Assuming it’s enough SOON enough

Intracellular volume becomes depleted--------------->>>>> shock----------->>>>>>>>> death.

Wt loss (usually rapid)

Decreased skin & tongue turgor

Thirst (maybe)

Dry oral mucous membranes

Furrowed tongue

Dizziness, weakness, confusion

Hypotension (esp orthostatic)

Tachycardia, decreased pulse volume, slow vein filling

Increased respiratory rate (slight to severe)

Changes in mental status

Difficulty swallowing

Flat neck jugular veins when supine

Difficulty speaking

Cool extremities, slow cap. refill

Infants/Small Children-----loss of tearing, depressed anterior fontanel

Urine specific gravity is increased

H&H increased

Blood Urea Nitrogen (BUN) increased

Unchanged Creatinine (if kidneys ok)

Serum electrolytes------variable depending on the type of fluid lost

Thorough Assessment re: FVD…. What’s YOUR plan?????????

Intent is to restore "normal" hydration and electrolyte concentration

Intent is to prevent renal damage, as well as other organ damage

When the deficit is not severe, the oral route is preferred for replacement, provided the pt can drink

During acute loss, IV route is required

As soon a pt is normotensive, a hypotonic sol (0.45 NS) is used to give lytes & free H20 for renal excretion of metab. wastes

Even with IV flds, po flds are given

Enteral fdgs may be necessary

Blood transfusions may be necessary

Fluid volume deficit r/t………aeb………..

Altered cerebral, renal, peripheral tissue perfusion r/t…….aeb………..

Risk for injury r/t………

Risk for impaired skin integrity..

Others???????

Consider all 6 criteria

assessment

doing for

assisting

teaching

consulting

counseling

Assessing

Assisting

Doing For

Teaching

Consulting

Counseling

The result of the abnormal retention of water and sodium in approximately the same proportions in which they normally exist in the ECF

Occurs secondary to an increase in sodium, which leads to an increase in water

Because there is isotonic retention of both substances, the serum NA+ concentration remains essentially normal

Mild to moderate isotonic fve in healthy people rarely has serious consequences because of the body’s compensatory mechanism

Increased circulating volume

Fluid shift to interstitial space

Decreased secretion of ADH & aldosterone

Increased cardiac output

Who might have poor compensatory mechanisms??????

Overhydration results in CHF & pulmonary edema

Compromised regulatory mechanisms, as in CHF, renal failure, cirrhosis

Impaired pituitary gland (ADH) or impaired adrenal cortex (aldosterone)

Excess intake of NA+ containing diet

Corticosteroid use

Excess intake of NA+ containing diet

Wt gain over short period

Peripheral (pitting or non-pitting) edema==========anasarca

Distended jugulars….even at high angle

Distended peripheral veins

Slow emptying of peripheral veins

Slow emptying of peripheral veins

Bounding full pulse

Dyspnea, orthopnea, cough, crackles, wheezes d/t fld accumulation in lungs

Pleural effusion, pulmonary edema

Ascites

Changes in mental status

Coma

Polyuria (if renal fx is wnl)

Increased pulse, resp, and bp

Anorexia, nausea

Decreased H&H

Decreased BUN

Unchanged Creatinine (if kidneys ok)

Low PaO2 if pulm edema exists

Electrolytes may/may not be abn.

Urine specific gravity decreased

CXR may reveal pulmonary effusion/pulmonary edema

Thorough Assessment re: FVE…. What’s YOUR plan?????????

Sodium Restricted Diet

Fluid Restriction (maybe)

Digitalis for CHF

Diuretics---Thiazides, Loop, Potassium-conserving

not without potential for side effects

given if renal failure NOT the cause of fluid retention

Bedrest

Fluid volume depletion

Hyponatremia

Hypokalemia/hyperkalemia

Hypomagnesemia

Hypocalcemia/hypercalcemia

Acid/base imbalances

FVE r/t…….aeb………

HR for impaired gas exchange r/t……aeb….

HR for impaired skin integrity r/t….aeb…..

HR for injury r/t….

Anxiety r/t……aeb……..

Risk for impaired physical mobility r/t…

Activity intolerance r/t fatigue aeb…..

Body image disturbance r/t edema

Others???