Fluid and electrolyt Basic physiology - PowerPoint Presentation

Slide1

Fluid and electrolyt

Slide2

Basic physiology

Water

largest single component of the body

Total body water

approx

75% of body

wt

at birth. & decreases with age.

TBW – divided into 2 main compartments

a, ICF (30-40%)

b, ECF (20-25%) –plasma (5%)

- interstitial (15%)

* transcellular (2%)- GI secretions, urine, CSF, pleural,

peritonial

, synovial

Slide3

Age & TBW

Age

Body water

ECF

ICF

Term

75

35-44

33

4-6months

60

23

37

12months

60

26-30

37

puberty

60

20

40

Adult

50-60

20

40

Slide4

Basic physiology

Plasma Osmolality

–

concn

of solute particles in plasma – 285-295mosm/kg/H

2

O

H

2

O is distributed b/w ICF & ECF according to amount of osmotically active solute in each compartment.

ECF solutes- Na

+

,Cl

-

,HCO

3

, glucose & urea

ICF solute - mainly K

+

Other solutes-ethanol,

mannitol,glycerol

may contribute to an extent to plasma osmolality

* At steady state-

-Osmolality of ICF= ECF = Plasma

Slide5

Body water osmolality

Normal osmolality = 285 – 295

mOsm

/kg

Change in ECF osmolality leads to change in ICF osmolality

Calculated from

E&u

and glucose conc.

2xNa + Glucose (mmol/L) + Urea (mmol/L)

Glu m/dl ÷ 18 =

glu

mmo

/L

Urea mg/dl ÷ 2.8 = urea mmol/L

Calculated value usually slightly less than measured value

Slide6

What is the plasma osmolality

Na = 140 mmol/L

Cl = 102 mmol/L

K = 4.6 mmol/L

Urea = 30 mg/dl

BGL = 80 mg/dl

Slide7

answer

295

mOsm

/kg

Urea produces “in-effective” osmolality since it diffuses freely across the cell membrane

Slide8

What is the osmolality?

4.3% dextrose / 0.18% saline

Answer

Dextrose = 4300mg ÷ 18 = 237 mmol/L

Sodium = 0.9 (154mmol) ÷ 5 = 30.8mmol x 2 = 62

Answer = 299 mmol/kg

Slide9

Maintenance fluid

Slide10

Adjustments in maintenance fluid

increased

decreased

Radiant warmer

meningitis

phototherapy

burns

Oliguria/anuria

dirrhoea

vomiting

Incubator- premature infant

polyuria

Surgical drain

Humidified ventilator

Sickle cell crisis

Nasogastric drain

Slide11

The commonest indication for fluid therapy in children is Diarrhea. Diarrheal diseases contribute 19% under-five deaths in developing countries and 65% diarrheal deaths are attributable to dehydration

Fluid therapies in children require careful planning, administration and monitoring as complications, some of which may be fatal, may complicate careless fluid therapy.

Slide12

DETERMINATION OF REQUIREMENTS

Fluid Requirements are categorized into 3:

Maintenance fluid requirement

Replacement of deficits:

Supplemental fluid therapy:

Replaces ongoing losses of fluids and electrolytes

Administered in addition to the maintenance and deficit fluid replacement therapies

Slide13

Dehydration

% deficit

outcome

Mild dehydration

5%

50ml/kg

Moderate dehydration

7.5% deficit

75ml/kg

Severe dehydration

10% deficit

100ml/kg

Slide14

Electrolyte content of ivf

solution

Sodium mmol/l

Potassium mmol/l

Chloride mmol/l

Lactate mmol/l

Ringers lactate

130

4

109

28

Normal saline

154

0

154

0

Half normal saline

77

0

77

0

Half strength

darrow’s

61

18

52

27

Slide15

Mode of fluid therapy

Oral fluid therapy

Parenteral fluid therapy

Others

intraosseous

Slide16

Types of dehydration

Classification based on:

Fluid volume depletion-Mild, Moderate and Severe dehydrations

Plasma tonicity [osmolality]-Hypotonic, Isotonic and hypertonic dehydrations

Sodium conc:

Hyponatraemic

,

Isonatraemic

and

Hypernatraemic

dehydrations

Slide17

Isotonic dehydration

Commonly caused by

diarrhoea

Net losses of water and sodium are in the same proportion as normally found in the Extracellular fluid

Features-

Balanced deficit of water and sodium

Serum sodium concentration is normal[130-150mmol/l

Serum osmolality is normal[275-295

mOsmol

/l

Hypovolaemia

occurs as a result of a substantial loss of ECF

Signs appear when losses exceed 5% body

wt

and worsen with increasing losses

Slide18

Hypertonic dehydration

Results from ingestion of fluids with high sodium or electrolyte content with poor intake of water or other hypo-

osmolar

fluids and poor absorption of the administered fluids. There is osmotic

diarrhoea

with loss of fluid from ECF

Features:

There is deficit of water and sodium, but the deficit of water is greater

Serum sodium concentration is elevated[>150 mmol/l];

Serum osmolality is elevated[> 295mOsmol/l]

Thirst is severe and out of proportion to the apparent degree of dehydration; the child is very irritable;

Seizures may occur, especially when serum sodium concentration exceeds 165 mmol/l

Slide19

Hypotonic dehydration

Results from intake of water or fluids with low solute content e.g. Dextrose infusions. The water is absorbed while sodium loss continues

Features

There is deficit of water and sodium but the deficit of sodium is greater

Serum sodium concentration is low-<130mmol/l

Serum osmolality is low-<275

mOsmol

/l

The child is lethargic and infrequently may have seizures

Slide20

Hypernatremic dehydration

This is the most dangerous form of dehydration due to complication of hypernatremia and of therapy.

Brain

haemorrhage

is the most devastating consequence of hypernatremia, other complications of hypernatremia include; thrombosis, central pontine

myelinosis

, extrapontine

myelinosis

.

Hypernatremia may cause fever,

hyperglycaemia

and mild

hypocalcaemia

Slide21

pathophysiology

Increase in ECF osmolality movement of water out of the brain cells

decrease brain volume tearing of intracerebral veins and bridging blood vessels

Brain

haemorrhage

seizures and coma

Slide22

Pathophysiology therapy

Rapid treatment of hypernatremia may cause significant morbidity and mortality

Idiogenic

osmoles are generated within the brain during the development of hypernatremia.

They increases the osmolality within the brain, providing protection against brain shrinkage caused by the movement of water out of the brain cell into the hypertonic ECF.

Idiogenic

osmoles dissipate slowly during correction of

hypernatraemia

Rapid lowering of the ECF during correction causes water movement from the ECF into the brain, producing cerebral

oedema

Slide23

Pathophysiology-therapy

Slide24

Treament of hypernatremic

dehydration

5% dextrose in half normal saline.

Correction is over 48-72hrs or more depending on the serum level of sodium

Slide25

Hyperkalaemia and hypok

What are the ECG features and correction

moderlaities

Slide26

Slide27

What is the sign