Fluid and Electrolyte BalanceM. Rasjad IndraLaboratorium Ilmu FaalFK. UNIBRAW

Body Fluid Compartment

Body Fluid Volume

Electrolyte Composition of Body Fluid

Electrolytes

Plasma

(mEq/L)

Interstitial Fluid (mEq/Kg H2O)

Intracellular Fluid (mEq/Kg H2O)

Cation:

Na+

142

145

10

K+

4

4

159

Ca2+

5

3

1

Mg2+

2

2

40

Total

153

154

210

Anion:

Cl-

103

117

3

HCO3-

25

28

7

Protein

17

-

45

Others

8

9

155

Total

153

154

210

Daily Intake and Output of Water (in ml/day)

Normal

Prolonged

Heavy Exercise

Intake

Fluid ingested

2100

?

From metabolism

200

200

Total intake

2300

?

Output

Insensible-Skin

350

350

Insensible-Lungs

350

650

Sweat

100

5000

Feces

100

100

Urine

1400

500

Total output

2300

6600

OsmosisThe net diffusion of water across the membrane from a region of high water concentration to one that has a lower water concentrationOsmoles (Osm):The measurement of total number of particles in a solution1 mole : 6.02 x 10231 mole/L NaCl ~ 2 osmoles/L (Na+ & Cl-)Osmotic pressure:The precise amount of pressure required to prevent the osmosis1 osm/L ~ 19,300 mmHg; 1 mosm/L~19.3mmHG

Add pure waterNormalAdd pure waterICFECFICFECF

Add isotonic salineNormalAdd isotonic salineICFECFICFECF

Add pure NaClNormalAdd pure NaClICFECFICFECF

Ingestion of 1L of waterCardiovascular stretch receptorDecreased ADH release from posterior pituitaryOsmoreceptorDecreased collecting duct water permiabilityDecreased water reabsorptionIncreased water excretionDecreased plasma ADH

DehydrationCardiovascular stretch receptorIncreased ADH release from posterior pituitaryOsmoreceptorsIncreased collecting duct water permiabilityIncreased water reabsorptionDecreased water excretionIncreased plasma ADHThirstIncreased water intake

Decreased effective arterial blood volumeAngiotensinogenReninAngiotensin ILiverAngiotensin IIBlood vesselsAdrenal cortexBrainVasoconstrictorAldosteron secre.Sodium reabs.Blood pressure >H2O reabsorptionADH secretionThirstWater intakeNormal effective arterial blood volume

Increased Potasium intakeIncreased plasma [K+]Direct effect on adrenal cortexIncreased [K+] in body cell (including kidney cells)Increased aldosterone secretionIncreased plasma aldosteroneIncrease luminal membrane permiablility to Na+ and K+ & Increase basolateral membrane Na+/K+-ATPase activity in collecting duct principal cells.Increased potasium secretionIncreased potasium excretionNormal potasium level

Definition of Edema:An increase in the interstitial compartement of extracellular fluid volume (Harrisons).Starling HypothesisThe balance of hydrostatic and oncotic pressures across the capillary endotheliumMean capillary hydrostatic pressure (Pc): 25 mmHgInterstitial fluid hydrostatic pressure (PIF): 0 mmHgCapillary oncotic pressure (c): 28 mmHgInterstitial fluid oncotic pressure (IF): 3 mmHgArterial end of capillary:Pc= 40 mmHg; PIF= 0 mmHgc= 28 mmHg; IF= 3 mmHgNet Filtration= 35-0-28+3= 10 Venous end of capillary:Pc= 10 mmHg; PIF= 0 mmHgc= 28 mmHg; IF= 3 mmHgNet Absorption= 15-0-28+3= -10

Causes of Extracellular Edema1. Increased capillary pressureExcessive kidney retentionHigh venous pressureDecreased arteriole resistance2. Decreased plasma proteinsLoss of protein in urineLoss of protein from denuded skinFailure of produce protein

3. Increased capillary permiabilityImmune reactionToxinBacteria infectionVitamin deficiency (exp. Vit C)4. Blockage of lymph returnCancerParacyte infection (Filaria)SurgeryCongenital absence or abnormal of Lymphatic vessels

ExerciceThe greatest fraction of the bodys water is contained within:a. Blood plasmab. Cellsc. Extracellular fluidd. Transcellular fluidIntravenous infusion of 1 liter of isotonic saline will:a. A 1-liter increase in intracellular fluid volumeb. A 1-liter increase in extracellular fluid volumec. A 0.5-liter increase in intra-cellular fluid volume and a 0.5-liter increase in extracellular fluid volume

Intravenous infusion of 1 liter of hypertonic saline will cause:a. A decrease in intracellular fluid volumeb. An increase in extracellular fluid volumec. An increase in plasma osmolalityd. All of the aboveAntidiuretic hormone increase epithelial water permiability of:a. Collecting ductsb. Proximal tubulesc. Thick ascending limbsd. All of the above

ADH release from the posterior pituitary is stimulated by:a. A fall in plasma osmolalityb. Severe hemorrhagec. Stimulation of arterial baroreceptorsd. Stretch of left arterial receptorWhich of the following produces a decrease in renal sodium excretion?a. Decrease plasma aldosterone levelb. Increase plasma level of atrial natriuretic peptidec. Increase GFRd. Increase renal sympa-thetic nerve activity

Which of the following produces an increase in renal sodium excretion?a. Administration of glucocorticoidsb. Decrease peritbular capilary hydrostatic pressurec. Increase plasma estrgen levelsd. Uncontroled diabetes mellitusRenin release is stimulated by:a. Increase blood pressure in afferent arteriolesb. Increase effective arterial blood volumec. Increase NaCl transport by macula densa cellsd. Stimulation of renal sympathetic nerves

Which of the following are commonly seen in patients with severe congestive heart failure?a. Elevated plasma ADH levelsb. Generalized edemac. Hyponatremiad. Thirste. All of the aboveThe most abundant intracellular cation is:a. Calciumb. Chloridec. Potasiumd. Sodium

Which of the following promotes a shift of potasium from cells to extracellular fluid?a. A fall in plasma pHb. An overdose of digitalisc. Inadequate blood flowd. Lack of insuline. All of the aboveWhich of the following produces excessive urinary excretion of potasium?a. Acute renal failureb. Inadequate aldosterone secretionc. Severe chronic renal failure (GFR=10 ml/min)d. Uncontroled diabetes mellitus

The following measurement were obtained in 3.40 kg newborn infant:Total body water2600 mlExtracellular water1490 mlPlasma water 155 mlWhat are the volumes of (1) The intracellular water and (2) the interstitial fluid-lymph water?