Fluid and electrolyte balance is essential for homeostasis. The document discusses how fluids are regulated through intake, output, and hormones to maintain balance. It describes the distribution of fluids inside and outside cells, and the four processes of fluid movement. Key electrolytes like sodium, potassium, and chloride are defined along with their distribution in intracellular and extracellular fluids. Acid-base balance is also explained, noting the respiratory and renal systems roles in regulation to keep blood pH within its normal range. Risk factors and medications that can impact balances are outlined.

1. Course : B.Sc Nursing
Subject : Fundamentals of Nursing
Unit : X
Topic : Fluid and Electrolyte Balance

3. OBJECTIVES
• At the end of the session the learner will be able to
• describe how fluid and electrolytes are regulated to
maintain homeostasis.
• discuss the fluid and electrolyte and acid base balances.
• Explain about the regulation of fluid and electrolyte
balances

4. INTRODUCTION
Fluid, electrolyte and acid base balance within
the body maintain health and function in all body
systems. These balances are maintained by the
intake and output of water and electrolytes, their
distribution in the body and regulated by the renal
and pulmonary system.

6. Distribution of
body fluids
INTRACELLULAR
FLUID
EXTRACELLULA
R FLUID
Interstitial fluid
Intravascular fluid
Transcellular fluid

7. Intracellular fluid
ICF comprises all fluid within the cells of the body,
about 42% of total body weight.
Extracellular fluid
ECF is all the fluid outside the cell.

8. COMPOSITION OF BODY FLUIDS
As water moves throughout the body, it contains
substances
Electrolyte
Minerals

9. MOVEMENT OF BODY FLUID
Each body compartment is separated by a cell wall
and capillary membrane. Fluids and solutes
move across these membranes by four
processes.
DIFUSSION
OSMOSIS
FILTRATION
ACTIVE TRANSPORT

14. REGULATION OF BODY FLUIDS
 Fluid intake
 Fluid output
 Hormonal influence

15. FLUID INTAKE (Thirst mechanism)

16. FLUID OUTPUT REGULATION
FLUID GAINS ML FLUID
LOSSES
ML
ORAL FLUIDS 1200 KIDNEYS 1500
SOLID FOODS 1000 SKIN 300
METABOLISM 300 LUNGS 500
GASTRO
INTESTINAL
200
TOTAL
GAINS
2500 TOTAL
LOSSES
2500

17. HORMONAL INFLUENCES
Anti diuretic hormone
Renin - Angiotensin aldosterone mechanism
Atrial natriuretic peptide

19. RENIN ANGIOTENSIN- ALDOSTERONE MECHANISM

20. ATRIAL NATRIURETIC PEPTIDE
It is a hormone secreted from atrial cells of the
heart in response to atrial stretching and an
increase in circulating blood volume.
It acts like a diuretic that causes sodium loss and
inhibits the thirst mechanism.
Inhibits the secretion of ADH and Aldosterone.

21. ELECTROLYTES
Electrolytes are the substances found in ECF
and ICF whose molecules dissociate into
electrically charged particles known as ions
when placed in water.

22. DEFINITIONS
IONS : Ions are electrically charged particles
CATIONS : Cations are positively charged
particles. E.g.- Na , K+, Ca2+ etc.
ANIONS : Anions are negatively charged
particles. E.g.- Cl-, PO4, HCO3-
ICF- K, Mg, PO4-, (K as a main ion)
ECF- Na, Ca, Cl (Na as a main ion)

23. ACID BASE BALANCE
ACID
Any compound which forms H⁺ ions in solution
(proton donors)
eg: Carbonic acid releases H⁺ ions
BASE
Any compound which combines with H⁺ ions in
solution (proton acceptors)
eg: Bicarbonate (HCO3⁻) accepts H+ ions

24. ACID-BASE BALANCE
• Normal blood pH: 7.35-7.45
• Maintenance of blood pH—Important
homeostatic mechanism of the body.
• If pH <7.35--------- Acidosis
Ph >7.45---------Alkalosis

25. RESPIRATORY ACID-BASE CONTROL
MECHANISMS
When chemical buffers alone cannot prevent
changes in blood pH, the respiratory system is
the second line of defence against changes.
Eliminate or Retain CO₂
Change in pH are RAPID
Occuring within minutes
PCO₂ ∞ VCO₂/VA

26. RENAL ACID-BASE CONTROL
MECHANISMS
The kidneys are the third line of defence
against wide changes in body fluid pH.
– movement of bicarbonate
– Retention/Excretion of acids
– Generating additional buffers
Long term regulator of ACID – BASE balance
May take hours to days for correction

27. RISK FACTORS AFFECTING FLUID,
ELECTROLYTE AND ACID-BASE BALANCE
Age Very young, very old
Gender Women
Environment Hot weather
Chronic disease Cancer, Cardiovascular
disease, congestive heart
failure, renal disease, COPD
Trauma Injuries, burns
Gastrointestinal
losses
Gastroentritis, nasogastric
suctioning

28. MEDICATIONS CAUSE FLUID,
ELECTROLYTE AND ACID BASE
IMBALANCE
 Diuretics
 Steroids
 Potassium supplements
 Respiratory center depressants
 Antibiotics
 Calcium carbonate
 Magnesium hydroxide
 Non steroidal anti-inflammatory drugs

29. NORMAL VALUES

30. CONCLUSION
• Electrolytes are minerals in your body that have an
electric charge. They are in your blood, urine, tissues,
and other body fluids. Electrolytes are important
because they help
• Balance the amount of water in your body
• Balance your body's acid/base (pH) level
• Move nutrients into your cells
• Move wastes out of your cells
• Make sure that your nerves, muscles, the heart, and
the brain work the way they should
• Sodium, calcium, potassium, chloride, phosphate, and
magnesium are all electrolytes. You get them from the
foods you eat and the fluids you drink.

31. REFERENCES
• Potter and Perry's Fundamentals of
Nursing (2017) 2nd Edition, Elsevier
Publication, page No.970-981.
• Kozier & Erb's Fundamentals of Nursing (10th
Edition), Pearson publication.
• Sr Nancy, Principles & Practice Of Nursing,
Nursing Arts Procedures (2006), NR
Brothers Publication.