week 4 dr zain, body fluids2014,2.ppt

8/10/2019 WEEK 4 Dr Zain, Body fluids2014,2.ppt

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Total body weight

100%

Interstitial F

15%

Plasma

5%

Transcelluar

1%

Water

60%

Other

40%

ECF

20%

ICF

40%



Body Fluids

Man: water constitutes 60% of body weight

Women: water constitutes 50% of bodyweight

Functional compartments of body fluids:

Intracellular space – 40% of body weight

Extracellular space –

20% of body weightInterstital – 15%

Plasma – 5%



Factors affecting body fluids

1. Water intake & output

2. Age:

- Infant: 73%Fetus- high content of water initially butdecreases progressively during late gestation and by 3-

5yrs age.- adults: 60%

3. Sex:

Adult male: 60%

Adult female: 40-50%

4. Obesity

5. Climate

6. Level of physical activity



Comparison in male and female



In average young adult male: Body composition

% of body weightBody composition

18%Protein, & related

substances

15%Fat

7%Mineral

60%Water



Adult 75kg

ICF- 400-450ml/kg or 0.4x75Kg= 30 L.

ECF- 150-200ml/kg (or 0.17x75Kg = 12 liters).

Blood volume – 60-65ml/kg (5 L)

Major components of ECF:

• plasma volume- 30-35ml/kg (3L)

• interstitial fluid 120-165ml/kg (8)

• Trans cellular fluids

-Also includes lymph, cerebrospinal fluid,synovial fluid, aqueous humor, vitreous body,

endolymph, perilymph, pleural, pericardial, and

peritoneal fluids



Normal Exchange of Fluid & Electrolytes

In steady state, water intake = water loss



Water intake regulation



Osm or mOsm unit for number of particles

1 mol of NaCl - 2 osm

Osmolarity - mOsm/L

Osmolality - mOsm/Kg water

Osmolality defines concentration of

solution

Tonicity defines effect of fluid on cell

volume

Osmotic Activity of Fluids

V l C l



Volume ControlOsmoreceptors - Day to day control

Baroreceptors - Respond to pressure change

The body sense any change of the osmotic pressure

by

Osmoreceptor cells in paraventricular/ supraopticnuclei

The body then respond to the change by

•Neural output

• Hormonal mediators



Osmoregulation

Excess free water (Posm 280)

Thirst inhibited

ADH declines

Urine dilutes to Uosm 100Osmoregulation

Decreased free water (Posm 295)

Thirst increased

ADH increases

Urine concentrates to Uosm 1200



The role of ADH:

•ADH = secreted in response to osmo;

= secreted in response to vol;

ADH = urinary concentration

• ADH acts on DCT / CD to reabsorb water

• Acts via V2 receptors & aquaporin 2

• Acts only on WATER



Fluid shifts in disease

• Fluid loss:

– GI: diarrhoea, vomiting, etc.

– Renal: diuresis, Absence of ADH or its receptors

causes diuresis called diabetes insipidus

–

Vascular: haemorrhage – Skin: burns

• Fluid gain:

–

Heart / liver / kidney failure:



ELECTROLYTE Composition

Electrolyte Conc Plasma (mEq/L) ISF ICF

Sodium, Na+ 142 141 10

Potassium, K+ 5 4.1 150

Calcium, Ca++ 5 4.1 -

Magnesium, Mg++ 3 3 40

(155)

Chloride, Cl- 103 115 15Bicarbonate, HCO3- 27 29 10

Biphosphate, HPO4- 2 2 100

Sulfate, SO4-2 1 1 20

Protein 16 1 60

Organic foods 6 3.4 -(155)

I t i t



Importanceimportance

• Maintaining ECF volume is critical to maintaining

blood pressure

• ECF osmolarity is of primary importance in long-term

regulation of ECF volume

• ECF osmolarity maintained mainly by NaCl balance:

• intake: 10.5g/d output: 10g/d in urine



FLUIDS and ELECTROLYTES

IV FLUID REPLACEMENT THERAPYTypes of Solutions

Isotonic

0.9% sodium chloride (NSS) Lactated Ringer’s sol’n Hypotonic 5% dextrose and water (D5W) 0.45% sodium chloride

0.33% sodium chloride Hypertonic 3% NaCl Protein sol’ns

Colloids Salt our albumin Plasmanate, Dextran



Factors affecting ADH

release



REGULATION OF FLUID INTAKE (THIRST)

decreased salivation decreased blood volume increased blood osmotic pressure

dry mouth and throat decreased blood pressure stimulation of hypothalamic

osmoreceptors

conscious awareness of thirst increased water intake

stimulation of tactile

receptors

increased

angiotensin II

stimulation of hypothalamic thirstcenter



REGULATION OF FLUID OUTPUT

dehydration

ANTIDIURETIC HORMONE

increased blood

osmolarity

stimulation of

hypothalamicosmoreceptors

rehydration

secretion of ADH

from posterior

pituitary gland

increased water

reabsorption

increased thirst

ALDOSTERONE

dehydration

rehydration

increased water

reabsorption

increased Na+

reabsorption

increased

aldosterone

increased

angiotensin II

ATRIAL NATRIURETIC PEPTIDE

increased blood volume

decreased Na+

reabsorption

decreased water

reabsorption

decreased blood volume

stretch of right atrium

secretion of ANP



REGULATION OF BODY

FLUIDSFluid intake

Fluid outputHormonal influence

Lymphatic influences

Neurologic influencesRenal influences



FLIUD IMBALANCES

The five types of fluid imbalances that mayoccur are:

Extracellular fluid imbalances(ECFVD)

Extracellular fluid volume excess(ECFVE)Extracellular fluid volume shift

Intracellular fluid vloume excess(ICFVE)

Intrcellular fluid volume deficit (ICFVD)



EXTRACELULLAR FLUID VOLUME DEFICIT

An ECFVD,: commonly called as dehydration , is a

decrease in intravascular and interstitial fluids

An ECFVD can result in cellular fluid loss if it issudden or severe

* The goal of treatment is to restore fluid

volume, replace electrolytes as needed, andeliminate the cause of fluid volume deficit.



THREE TYPES OF ECFVD

Hyperosmolar fluid volume deficit- water loss is greater than the

electrolyte loss

- the clinical problems that occur result from alterations in the

concentrations of specific plasma electrolytes.

- fluid moves the intracellular compartment into the plasma and

interstitial fluid spaces, causing cellular dehydration and

shrinkage.

Isosmolar fluid volume deficit (hypovolemia) –

equal proportionof fluid and electrolyte loss .

- most common type of dehydration.

- results in decreased circulating blood volume and inadequate

tissue perfusion.Hypotonic fluid volume deficit – electrolyte loss is greater than

fluid loss.

- fluid moves from the plasma and interstitial fluid spaces into

the cells, causing a plasma volume deficit and causing cells to

swell



1. ISOTONIC DEHYDRATION

a. Inadequate intake of fluids and solutes.

b. Fluid shifts between compartments

c. Excessive losses of isotonic body fluids2. Hypertonic dehydration – conditions that increase fluid

loss, such as:

excessive perspiration, hyperventilation, ketoacidosis,

prolonged fevers, diarrhea, early stage renal failure and

diabetes insipidus.

3. Hypotonic dehydration

a. Chronic illnessb. Excessive fluid replacement (hypotonic)

c. Renal failure

d. Chronic malnutritio



Extracellular fluid volume excess

ECFVE is increased fluid retention in theintravasular and interstitial spaces

Fluid intake or fluid retention exceeds

the fluid needs of the body.

Fluid volume excess is also called

OVERHYDRATION or fluid overload

TYPES



TYPES:

1. I sotonic Overhydration

a. known as hypervolemia, isotonic overhydrationresults

from excessive fluid in the ECF compartment.

b. Only the ECF compartment is expanded, and fluid does

not shift between the extracellular and intracellular

compartment.

c. Isotonic hydration causes circulatory overload and

interstitial edema; when severe or when it occurs in a clientwith poor carediac function, CHF and pulmonary edema can

result.

2. Hypertonic overhydration

a. Occurence of hypertonic overhydration is rare and is

caused by an excessive sodioum intake

b. Fluid is drawn from the intracellular fluid compartment;

the extracellular fluid

volume expands; and the intracellular fluid volume decrease



Oedema Definition

An increased volume of interstitial fluid in a tissue or

organ

May be localised or generalised (systemic)

Causes of Oedema

Raised capillary pressure

Reduced oncotic pressure

Endothelial damage (inflammation)

Impaired lymphatic drainage

O d



Oedema

O d



Oedema



Raised Capillary Pressure

Cardiac failure

right ventricular failure - systemic oedema

left ventricular failure - pulmonary oedema

congestive cardiac failure - both

Local venous obstruction

deep vein thrombosis

external compression



Reduced Oncotic Pressure Renal disease

loss of albumin across glomerulus Hepatic disease

inadequate albumin synthesis

Malnutrition

inadequate albumin synthesis

Lymphatic Obstruction

Tumours

Fibrosis Inflammation

Surgery

Congenital abnormality

Generalised Oedema

Congestive cardiac failure

Right ventricular failure

Renal disease

Li di

week 4 dr zain, body fluids2014,2.ppt

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