Cairan Tubuh Dan Elektrolit Kul 20071

8/11/2019 Cairan Tubuh Dan Elektrolit Kul 20071

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Cairan tubuh danelektrolit

Dr.H.Hasrul Han

Bag: Patologi klinik FK Unsri



Body Fluids - distribution

Body fluids constitute 55-

60% of body mass

• Higher in males due to

greater muscle mass and

lower fat

Total body water declines

throughout life with

changes in muscle mass

and fat

Water occupies 2 main

fluid compartments:

• Intracellular (~2/3 of

total water)

•

Extracellular (~1/3 totalwater)



Water balance

Normally body fluid volumeremains constant

• water loss = water gain

Water gain:

• ~60% ingested liquids

• ~30% ingested in foods

• ~10% metabolic water(from oxidation)

Water loss:

•

~4% faeces• ~28% insensible water loss

(skin & lungs)

• ~8% perspiration

• ~60% urine

Additional fluid loss inmenstrual flow in females ofre roductive a e



Regulation of body water gain and

loss

Regulation of body water gaindepends mainly on regulatingvolume of water intake• Thirst centre in hypothalamus

governs urge to drink

Thirst centre stimulated by :

• Nerve impulses fromosmoreceptors in hypothalamus in PV or in plasma osmolality

• Hypothalamic osmoreceptors lose waterto plasma

Increased transmission of nerveimpulses to thirst centre

• dry mouth and pharynx - lesssaliva from blood plasma

• in PV = BP increased angiotensin II (via JGA)

• stimulates thirst centre

Regulation of body water (andsolute) loss depends mainly on



Fluid Balance



Water loss

Ambient air temperature

Solar and thermal radiation

Water vapor pressure (humidity)

Solutes and wastes to be excreted Amount and timing of activity

Amount of water intake

Physiological, behavioral, andanatomical adaptations to reducewater loss



Insensible water loss

(unaware of)

Not precisely regulated

Evaporation (respiration and skin)

Independent of sweating(anhydrosis)

Minimized by cholesterol-filledcornified layer of skin (barrier)

Increase loss in burn patients (10x)



Sweating

Highly variable

Dependent on physical activity andenvironment temperature

↑ water intake via thirst mechanism

Loss via feces Normally small amount

Severe during diarrhea



Water loss via kidney

The most important regulator of water and

electrolyte balance Several mechanisms controlling the rate of

excretion

↓ water excretion (dehydration), ↑ excretion

with ↑ increased intake (same for electrolyte) Kidneys adjust the excretion rate to match

intake and disease state



Body Fluid Compartments

Extracellular• Interstitial fluid and plasma (non-

cellular part of blood)

Transcellular (specialized type ofextracellular fluid)

• Cerebrospinal fluid, intraocular fluid,GI tract, potential fluid (peritoneal, joint space)

Intracellular



Fluid andelectrolytescome into theplasma thenredistribute to

the other fluidcompartmentsover time.Note also the

lymphatics asa recirculatorof plasmaproteins



Body Fluid Compartments

Total body water - 50-60 % of body weight

• decrease with age, gender and obesity

Intracellular water - 40% of body weight

• 75 trillion cells

• Similar composition in different species

Extracellular water - 20% of body weight

• % is important in fluid therapy• Transcellular accounts for ~ 1-2 liters



Plasma

Plasma is the liquid portion of the blood that is

separated from the blood cells by centrifugation. One of the characteristics of plasma is that it clots

easily.

Serum plus clotting factors is plasma, and clottedplasma yields serum (as an interesting aside,

"serum" is Latin for whey, the liquid portion ofclotted milk removed in making cheese).



Plasma

Exchanges substances withinterstitial fluid via pores of thecapillary membrane

Pores permeable to all solutes inextracellular fluid, except proteins

Plasma have higher proteinconcentration



Composition of extracellular and

intracellular fluids



Theserepresent thenon-electrolytes in

the plasma.They alsocontributeosmolarity to

the plasma orextracellularfluid.





Intracellular volume• Can not be measured directly

• Calculated as Total body water -Extracellular volume

Plasma volume•

Indicator can not permeate capillarymembrane

• Most common 125I-albumin, alsoEvans blue dye (T-1824)

Interstitial volume • Can not be measured directly

• Calculated as Extracellular volume -Plasma volume



Forces impacting fluid distribution

Plasma vs Interstitial Space

• Balance between Hydrostatic and

Colloid Osmotic forces across thecapillary membranes

Intracellular vs Extracellular• Osmotic effect (e.g. electrolytes)



Osmosis

Osmosis is the net movement of

water molecules over a partiallypermeable membrane from an areaof less osmotic potential to an areaof more negative osmotic potential.



Excessive loss of H2O from

ECF

1 2 3

ECF osmotic

pressure rises Cells lose H2O

to ECF by

osmosis; cells

shrink

(a) Mechanism of dehydration

Osmosis



Osmosis

Excessive H2O enters

the ECF

1 2

ECF osmotic

pressure falls

3 H2O moves into

cells by osmosis;

cells swell

(b) Mechanism of hypotonic hydration



Osmotic Pressure

Determined by number of particles perunit volume, not by mass! (Molar

Concentration)

1 molecule of Albumin (mw 70000) and 1molecule of Glucose (mw 180) has sameosmotic effect



What is the osmotic pressure of a 0.9%

NaCl solution?

0.9 % NaCl solution= 0.9g in 100 ml ofsolution or 9g/1L

MW of NaCl =58.5

X mM=X mg/mw x 1000ml/ X ml

X mM=900mg/58.5 x 1000/100

154 mM = 154 mOsm

But wait, NaCl dissociates. So 154 x 2=308mOsm/L

Potential osmotic pressure would be 308 x19.3 mm Hg/mOsm/L or 5944 mm Hg



What is the osmotic pressure of a 5%

glucose solution?

Glucose mw=180

5g of glucose in 100mL of solution

X mM=5000 mg/180 x1000ml/100mL

278 mM = 278 mOsm Potential osmotic pressure would be

278 x 19.3 mm Hg/mOsm/L or 5366mm Hg





Osmolarity of body fluids

Interstitial fluid and plasma (80% Na+

and Cl- ions)

Intracellular fluid (50% K+ ions)

Total osmolarity of each around 300mOsm/L

Plasma 1 mOsm/L greater because ofosmotic affect of plasma proteins (20mmHg greater pressure in the

capillaries)

F h i i ll l d



Factors that impact intracellular and

extracellular volume

Ingestion of water

Dehydration

IV infusion of differentsolutions

Loss of fluid via GI tract

Loss via sweat

Loss via kidneys



Important principles for fluid therapy

Water moves rapidly across cellmembranes

• Osmolarity between compartments

will be almost exactly except for afew minutes after one changes

Cell membranes are almost

completely impermeable to manysolutes

• Osmoles remains constant, unlesssolutes are added or lost from the

extracellular compartment



Edema Formation



Edema Formation

“Excess fluid in body tissue” Most cases in the extracellular fluid

compartment

Can also occur in the intracellular fluidcompartment as well

Extracellular - pitting edema Decreased kidney excretion of salt andwater

Disease state (acute glomerulonephritis) with failure to filtrate

adequate amounts of fluid

Decreased plasma proteinsFailure of body to produce normal amounts of proteinsLeakage of proteins from plasma

Decreased plasma proteins (con’t)



Decreased plasma proteins (con t)

1. Nephrotic syndrome (damage to themembranes of the renal glomeruli). Seriousedema when plasma protein falls below

2.5g/100ml.2. Cirrhosis of the liver (hepatic tissue fibrosis). ↓ protein synthesis leading to ↓ colloid osmoticpressure.

Elektrolition in the body fluid

1. Kation (Na,K,Ca,Mg)

2. Anion (Cl)

3. Penting pada perawatan penyakitakut



Tujuan:

D/ dan Th/ gangguan elektrolit

Monitor hasil Th/

Mencegah komplikasi

C a r a :

Flame emission spectrophotometry

Ion selective electrode (ISE) Spectrofotometer kinetik



Fungsi Kation

Na :tek. Osmotik CES, aktifitas neuromuskuler,mempengaruhi asam basa, Cldan K serta membantu pengeluar-an air.

K: tek.Osmotik CIS, aktifitas enzym danneuromuskuler, mempengaruhi asam basadan fungsi ginjal

Ca: aktifitas neuromuskuler,perkem-

bangan rangka, pembekuan darah, Mg: aktifitas intraseluler dan

mempengaruhi level Na,K,Ca dan fosfor



Fungsi Anion

Cl: mempengaruhi asam basa, menjaga tek.Osmotik darah.

HCO3: sistem bufer yg mengatur pHHPO4: mengatur level Ca, metabolisme

energi dan asam basa



Nilai Rujukan

Na: 135 – 145 mEq/L

K: 3,8 – 5,5 mEq/L

Ca: 8,9–

10,1 mg/dL anak sp 10,6 Mg: 1,7 – 2,1 mg/dL

Cl: 100 – 108 mEq/L

PO4: 2,5 – 4,5 mg/dL anak 7mg/dL

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Cairan Tubuh Dan Elektrolit Kul 20071