Fluids & Electrolytes

FLUID & FLUID & ELECTROLYTESELECTROLYTES

Fundamnetal of nursing 2

FUNGSI CAIRAN TUBUH

Sarana untuk mengangkut zat-zat makanan ke sel-sel

Mengeluarkan buangan-buangan selMmbantu dalam metabolisme selSebagai pelarut untuk elektrolit dan non

elektrolitMembantu memelihara suhu tubuhMembantu pencernaanMempemudah eliminasiMengangkut zat-zat seperti (hormon, enzim,

SDP, SDM)

FLUIDS

50-60% of the human body is water (decreases with age)

Body fluids are classified according to their location with most of the body’s fluids found within the cell Intracellular Extracellular (mainly responsible for transport of nutrients

and wastes)

Fluid compartments are separated by selectively permeable membranes that control movement of water and solutes

The process of homeostasis involves delivery of oxygen and nutrients to the cells and removal of waste

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Body Fluid Compartments2/3 (65%) of TBW is intracellular (ICF)1/3 extracellular water

25 % interstitial fluid (ISF) 5- 8 % in plasma (IVF intravascular fluid)1- 2 % in transcellular fluids – CSF,

intraocular fluids, serous membranes, and in GI, respiratory and urinary tracts (third space)

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Fluid compartments are separated by membranes that are freely permeable to water.

Movement of fluids due to: hydrostatic pressure osmotic pressure\

Capillary filtration (hydrostatic) pressureCapillary colloid osmotic pressureInterstitial hydrostatic pressureTissue colloid osmotic pressure

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BalanceFluid and electrolyte homeostasis is

maintained in the bodyNeutral balance: input = outputPositive balance: input > outputNegative balance: input < output

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Solutes – dissolved particles

Electrolytes – charged particlesCations – positively charged ions

Na+, K+ , Ca++, H+

Anions – negatively charged ionsCl-, HCO3

- , PO43-

Non-electrolytes - Uncharged Proteins, urea, glucose, O2, CO2

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Body fluids are:Electrically neutralOsmotically maintained

Specific number of particles per volume of fluid

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Homeostasis maintained by:

Ion transportWater movement Kidney function

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MW (Molecular Weight) = sum of the weights of atoms in a molecule

mEq (milliequivalents) = MW (in mg)/ valence

mOsm (milliosmoles) = number of particles in a solution

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Tonicity

Isotonic

Hypertonic

Hypotonic

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Cell in a hypertonic solution

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Cell in a hypotonic solution

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Movement of body fluids “ Where sodium goes, water follows.”

Diffusion – movement of particles down a concentration gradient.

Osmosis – diffusion of water across a selectively permeable membrane

Active transport – movement of particles up a concentration gradient ; requires energy

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ICF to ECF – osmolality changes in ICF not rapid

IVF → ISF → IVF happens constantly due to changes in fluid pressures and osmotic forces at the arterial and venous ends of capillaries

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Regulation of body water

ADH – antidiuretic hormone + thirstDecreased amount of water in bodyIncreased amount of Na+ in the bodyIncreased blood osmolalityDecreased circulating blood volume

Stimulate osmoreceptors in hypothalamusADH released from posterior pituitaryIncreased thirst

Regulation of Fluid Volume

Kidneys Capillary pressure forces fluid through the

walls and into the tubuleAt this point H2O or electrolytes are then

either retained or excretedThe urine becomes more dilute or more

concentrated based on the needs of the body

Regulation of Fluid Volume, cont.

Antidiuretic hormone (ADH)Produced by the hypothalamusStored in the pituitary glandRestores blood volume by increasing or decreasing

excretion of water Increased osmolality or decreased blood volume

stimulates the release of ADHThen the kidneys reabsorb waterAlso may be released by stress, pain, surgery, and

some meds


Renin-angiotensin-aldosterone systemRenin secreted in kidney

Amount of renin produced depends on blood flow and amount of Na in the blood

Produces angiotensin II (vasoconstrictor)Angiotensin causes peripheral

vasoconstrictionAngiotensin II stimulates the production of

aldosterone


AldosteroneSecreted by the adrenal gland response to

angiotensin IIThe adrenal gland may also be stimulated by the

amount of Na and K + in the bloodCauses the kidneys to retain Na and H2OLeads to increases in fluid volume and Na levelsDecreases the reabsorption of K+Maintains B/P and fluid balance

Regulation of Fluid Volume, cont

Atrial natriuretic peptide or factor (ANP) (ANF)Cardiac hormoneReleased in response to increased pressure in the

atria (increased blood volume)Opposes the renin-angiotensin-aldosterone systemStimulates excretion of Na and H2OSuppresses renin levelDecreases the release of aldosteroneDecreases ADH releaseReduces vascular resistance by causing vasodilation

REGULATION OF FLUID VOLUME

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Result:increased water consumptionincreased water conservation

Increased water in body, increased volume and decreased Na+ concentration

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Dysfunction or trauma can cause:Decreased amount of water in bodyIncreased amount of Na+ in the bodyIncreased blood osmolalityDecreased circulating blood volume

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Edema is the accumulation of fluid within the interstitial spaces.

Causes:increased hydrostatic pressure

lowered plasma osmotic pressure

increased capillary membrane permeability lymphatic channel obstruction

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Hydrostatic pressure increases due to:

Venous obstruction:

thrombophlebitis (inflammation of veins)

hepatic obstruction

tight clothing on extremities

prolonged standing

Salt or water retention

congestive heart failure

renal failure

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Decreased plasma osmotic pressure:

↓ plasma albumin (liver disease or protein malnutrition)

plasma proteins lost in :

glomerular diseases of kidney

hemorrhage, burns, open wounds and cirrhosis of liver

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Increased capillary permeability:

Inflammation

immune responses

Lymphatic channels blocked:

surgical removalinfection involving lymphatics

lymphedema

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Volume Abnormalities

Edema the accumulation of fluid within the interstitial

space

Causes:

•increased hydrostatic pressure

• venous obstruction, lymphedema, CHF, renal failure

•lowered plasma osmotic pressure (protein loss)

• liver failure, malnutrition, burns

•increased capillary membrane permeability

• Inflammation, SIRS, sepsis

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Volume Abnormalities

Edema the accumulation of fluid within the interstitial space

Results in:• increased distance for diffusion

• impaired blood flow

• slower healing

• increased risk of infection

• pressure sores over bony prominences

• impaired organ function (brain, liver, gut, kidney)

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Edema of specific organs can be life threatening (larynx, brain, lung)

Water is trapped, unavailable for metabolic processes. Can result in dehydration and shock. (severe burns)

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Electrolytes

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Electrolyte balance

Na + (Sodium) 90 % of total ECF cations 136 -145 mEq / LPairs with Cl- , HCO3

- to neutralize charge

Low in ICF Most important ion in regulating water

balanceImportant in nerve and muscle function

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Regulation of Sodium

Renal tubule reabsorption affected by hormones:AldosteroneRenin/angiotensinAtrial Natriuretic Peptide (ANP)

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Potassium

Major intracellular cationICF conc. = 150- 160 mEq/ LResting membrane potentialRegulates fluid, ion balance inside cellpH balance

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Regulation of Potassium

Through kidneyAldosteroneInsulin

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Isotonic alterations in water balance

Occur when TBW changes are accompanied by = changes in electrolytesLoses plasma or ECFIsotonic fluid loss

↓ECF volume, weight loss, dry skin and mucous membranes, ↓ urine output, and hypovolemia ( rapid heart rate, flattened neck veins, and normal or ↓ B.P. – shock)

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Isotonic fluid excessExcess IV fluidsHypersecretion of aldosteroneEffect of drugs – cortisone

Get hypervolemia – weight gain, decreased hematocrit, diluted plasma proteins, distended neck veins, ↑ B.P.

Can lead to edema (↑ capillary hydrostatic pressure) pulmonary edema and heart failure

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Electrolyte imbalances: Sodium

Hypernatremia (high levels of sodium)Plasma Na+ > 145 mEq / LDue to ↑ Na + or ↓ waterWater moves from ICF → ECFCells dehydrate

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Hypernatremia Due to:Hypertonic IV soln.Oversecretion of aldosteroneLoss of pure water

Long term sweating with chronic fever

Respiratory infection → water vapor loss

Diabetes – polyuriaInsufficient intake of water (hypodipsia)

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Clinical manifestationsof Hypernatremia

ThirstLethargyNeurological dysfunction due to

dehydration of brain cellsDecreased vascular volume

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Treatment of Hypernatremia

Lower serum Na+Isotonic salt-free IV fluidOral solutions preferable

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HyponatremiaOverall decrease in Na+ in ECFTwo types: depletional and dilutionalDepletional Hyponatremia

Na+ loss:diuretics, chronic vomitingChronic diarrheaDecreased aldosteroneDecreased Na+ intake

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Dilutional Hyponatremia:Renal dysfunction with ↑ intake of hypotonic

fluidsExcessive sweating→ increased thirst →

intake of excessive amounts of pure waterSyndrome of Inappropriate ADH (SIADH) or

oliguric renal failure, severe congestive heart failure, cirrhosis all lead to:Impaired renal excretion of water

Hyperglycemia – attracts water

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Clinical manifestations of Hyponatremia

Neurological symptomsLethargy, headache, confusion, apprehension,

depressed reflexes, seizures and coma

Muscle symptoms Cramps, weakness, fatigue

Gastrointestinal symptomsNausea, vomiting, abdominal cramps, and

diarrhea

Tx – limit water intake or discontinue meds

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Hypokalemia

Serum K+ < 3.5 mEq /LBeware if diabetic

Insulin gets K+ into cellKetoacidosis – H+ replaces K+, which

is lost in urine

β – adrenergic drugs or epinephrine

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Causes of Hypokalemia

Decreased intake of K+

Increased K+ lossChronic diureticsAcid/base imbalanceTrauma and stressIncreased aldosteroneRedistribution between ICF and ECF

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Clinical manifestations of Hypokalemia

Neuromuscular disordersWeakness, flaccid paralysis, respiratory

arrest, constipationDysrhythmias, appearance of U wavePostural hypotensionCardiac arrestOthers – table 6-5Treatment-

Increase K+ intake, but slowly, preferably by foods

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Hyperkalemia

Serum K+ > 5.5 mEq / LCheck for renal diseaseMassive cellular traumaInsulin deficiencyAddison’s disease Potassium sparing diureticsDecreased blood pHExercise causes K+ to move out of cells

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Clinical manifestations of Hyperkalemia

Early – hyperactive muscles , paresthesiaLate - Muscle weakness, flaccid paralysisChange in ECG patternDysrhythmiasBradycardia , heart block, cardiac arrest

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Treatment of Hyperkalemia

If time, decrease intake and increase renal excretion

Insulin + glucoseBicarbonateCa++ counters effect on heart

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Calcium ImbalancesMost in ECFRegulated by:

Parathyroid hormone↑Blood Ca++ by stimulating osteoclasts↑GI absorption and renal retention

Calcitonin from the thyroid glandPromotes bone formation↑ renal excretion

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HypercalcemiaResults from:

Hyperparathyroidism Hypothyroid statesRenal diseaseExcessive intake of vitamin DMilk-alkali syndromeCertain drugsMalignant tumors – hypercalcemia of malignancy

Tumor products promote bone breakdownTumor growth in bone causing Ca++ release

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HypercalcemiaUsually also see hypophosphatemiaEffects:

Many nonspecific – fatigue, weakness, lethargyIncreases formation of kidney stones and

pancreatic stonesMuscle crampsBradycardia, cardiac arrestPainGI activity also common

Nausea, abdominal crampsDiarrhea / constipation

Metastatic calcification

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HypocalcemiaHyperactive neuromuscular reflexes and

tetany differentiate it from hypercalcemiaConvulsions in severe casesCaused by:

Renal failureLack of vitamin DSuppression of parathyroid functionHypersecretion of calcitoninMalabsorption statesAbnormal intestinal acidity and acid/ base bal.Widespread infection or peritoneal inflammation

HypocalcemiaDiagnosis:

Chvostek’s signTrousseau’s sign

TreatmentIV calcium for acuteOral calcium and vitamin D for chronic

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Most commonly from gastric lossesEmesis, gastric suctioning, EC fistula

Often presents as a contraction alkalosis with paradoxical aciduria (Na+ retained and H+ wasted in the kidney)

Rx: resuscitation with normal saline

Hypochloremia

Most commonly from over-resuscitation with normal saline

Often presents as a hyperchloremic acidemia with paradoxical alkaluria (H+ retained and Na+ wasted in the kidney)

Rx: stop normal saline and replace with hypotonic crystalloid

Hyperchloremia

Fluids & Electrolytes

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