This document provides an overview of body fluids and electrolytes. It discusses daily fluid intake and output, body fluid compartments, blood volume, compositions of extracellular and intracellular fluid, types of fluids used for fluid replacement, and key electrolytes including sodium, potassium, and calcium. For each electrolyte, it covers normal levels, causes and symptoms of hypo- and hyper- conditions, and general treatment approaches. The document contains detailed but concise explanations of fluid and electrolyte physiology.

1. SUZA
SURGERY
DR.SAID A. SAID
24-May-23 Body Fluids 1

2. .
•BODY FLUID AND
ELECTROLYTES
24-May-23 Body Fluids 2

3. INTRODUCTION
• Surgical illness and operative intervention
disrupt homeostasis and lead to changes in
fluid, electrolyte and acid– base balance.
• A grasp of the surgical physiology involved is
vital for understanding the principles of
preoperative and postoperative care.
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4. COUNT….
The monitoring and alteration of fluid and
acid–base status comprise the principal aspects
of the care of surgical patients.
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5. Overview
 BODY FLUIDS
 ELECTROLYTE
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6. FLUID INTAKE AND OUTPUT
 During steady state conditions
Total amount of body fluids and the
concentration of solutes remain relatively
constant
 There is continuous exchange of fluids and
solutes with
External environment
Different compartments of body
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7. Daily Water Intake
 Two major sources
Ingested in form of Liquid & Water in food
about = 2200 ml/day
Synthesized in the body by Oxidation of
carbohydrates about = 300 ml/day
–Total intake = 2500 ml/day
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8. Daily Water Intake
 Water intake very variable
From person to person
In the same individual
• Depends on Climate, habits, level of
physical activity
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9. Daily Loss of Body Water
 Insensible fluid loss
Evaporation
In respiratory tract = 400 ml/day
Through the skin = 400 ml/day
–Total insensible loss = 800 ml/day
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10. Daily Loss of Body Water..
Insensible loss via skin
Independent of sweating
Minimized by cornified layer of the skin
 Burns : rate of evaporation increases
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11. Daily Loss of Body Water…
 Fluid loss in sweat.
Highly variable depend on
Environmental temperature(hot weather)
Level of physical activity(exercise)
Normally = 100 ml/day
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12. Daily Loss of Body Water
 Water loss in faeces
Small amount = 100 ml/day
But amount lost increases tremendously in
severe diarrhea
 Water loss by kidneys
Variable
As low as 0.5l/day in dehydration
As high as 20 l/day in a person with
excessive fluid intake
Normally about =1500 ml/day
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13. Daily Water Balance
Water input (ml/day) Water output (ml/day)
Fluid intake 1,200
Insensible loss
(lungs&skin)
800
H2O in food 1,000 Sweat 100
Metabolically
produced
300 Feces 100
Kidney 1,500
TOTAL INPUT 2,500 TOTAL LOSS 2,500
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14. BODY FLUID COMPARTMENTS
 Total body fluid distributed among three major
compartments
Intracellular fluid compartment (ICF)
Extra cellular fluid compartment (ECF)
which include plasma & interstitial fluid.
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15. BODY FLUID COMPARTMENTS
Trans-cellular fluid compartment(TCF)
 Fluid in lumen of epithelial cells: gall
bladder, intestine, CSF, intra ocular,
synovial fluid , pleural and pericardium
cavity
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16. TOTAL BODY WATER
 Total fluid volume constitute 60% of the total
body weight)
40% intracellular Volume (ICV) - 2 liters is red
cell volume
 20% is extracellular volume
- 4% is plasma volume
- 16 is interstitial fluid volume
The main cat ion in the extracellular fluid is
Na+ which is 140 meq/litre
Intracellular potassium concentration is 150
meq/litre

17. Total Body Water
Women have more fat
Contain less water than men (total
body water is 45 – 50% of body wt)
Children
neonate contain more water than
adults (75 - 80% TBWt)
By about 1 yr body water = 60% of
body wt
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18. Fluid Compartments
Intracellular Fluid
Volume = 28 L,
2/3 TBW
Interstitial
Fluid
Volume =
10.5 L,
75% of ECF
Plasma
Vol = 3.5
L, 25% of
ECF
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ICF (2/3 TBW) ECF (1/3 TBW)
Total Body Water (TBW) 42 L, 60% of Body Wt

19. BLOOD VOLUME
 Blood contains both ECF and ICF
–ICF is the fluid within the RBC
 Average Blood volume = 8% of body wt= 5.6
–On the average
• 60% of blood vol = plasma ( 3 liters)
• 40% of blood vol = RBC (2 liters)
–Values vary considerably in different people
depending on
• Sex, weight, and other factors
19

20. Compositions of ECF
• Plasma and interstitial fluid
– Separated by highly permeable
capillary membrane
– Ionic composition similar
• Permeability of protein is small
– Small amount of protein leak into
interstitial space
• For practical purposes
– Concentration of ions in plasma
and ICF are equal
24-May-23 Body Fluids 20
plasma
ICF
Interstitial
fluid
Capillary

21. Compositions of ECF
• ECF contain
• Large amounts of
– Na+ = 145 mEq/L
– Cl- = 140 mEq/L
– HCO3
- = 24 mEq/L
• Small quantities of
– K+ = 4 mEq/L
– Ca++ = 1 mEq/L
– mg++ = 1.5 mEq/L
– Organic acids, Sulfates,
Phosphates
24-May-23 Body Fluids 21
plasma
ICF
Interstitial
fluid
Capillary

22. Compositions of ICF
• ICF separated from ECF by
a selectively permeable
membrane
– It is highly permeable to water
– Not highly permeable to most
electrolytes
• ICF contains
– Small amount of
• Na+ = 14 mEq/L
• Cl- = 10 mEq/L
24-May-23 Body Fluids 22
plasma
ICF
Interstitial
fluid
Capillary

23. Compositions of ICF
• ICF contains
– Mod. Amount of
• Mg++ = 12 mEq/L
• SO-
4 = 20 mEq/L
– Large amounts of
• K+ = 140 mEq/L
• PO2-
4 = 40 mEq/L
• Prot -
• SO-
4
24-May-23 Body Fluids 23
plasma
ICF
Interstitial
fluid
Capillary

24. 24-May-23 Body Fluids 24
Ionic Composition of Body Fluids
200
150
50
100
0
meq/L H2O
Na+
K+
Cl-
Pr-
HCO3-
Na+ Cl-
HCO3-
Na+
Na+
K+
K+
Pr-
HCO3-
Cl-
Phosphates
Plasma Interstitial
fluid
Intracellular fluid

25. 24-May-23 Body Fluids 25
1. Crystalloids
Normal saline
Dextrose saline
Hartmann’s solution
2. Colloids
Natural, e.g. blood, albumin
Synthetic, e.g. gelatin-based infusions
TYPES OF FLUIDS

26. 24-May-23 Body Fluids 26
On the wards you will mainly use
crystalloids to provide the normal daily
requirement and replace additional losses.
Three major types of fluid are used: 0.9%
sodium chloride, dextrose saline and 5%
dextrose.
The composition of these fluids is shown

27. 24-May-23 Body Fluids 27
1 L 0.9% sodium chloride contains 153
mmol NaCl.
 1 L dextrose saline contains 31 mmol
NaCl + 40 g dextrose.
 1 L 5% dextrose contains 50 g dextrose.
Potassium can be added to these solutions in
the form of potassium chloride (KCl).

28. ELECTROLYTES
SODIUM
• It Is the principal extracellular cation and
solute
• Essential for generation of action potential
in neurologic and cardiac tissue
• Increases or decreases of total body sodium
correspond with increase or decreases of
ECV and PV

29. HYPONATREMIA
 Defined as (Na+) < 130 meq/L
 It may occur as a result of water retention,
sodium loss or both

30. HYPONATREMIA
 Most common clinical association with
hyponatraemia is:
Post operative state
Acute intracranial disease
Malignant disease
 Kidney diseases
 Gastrointestinal losses
 Use of diuretics (especially with along with low
sodium diet)

31. SIGN & SYMPTOMS
 Depends on both the rate and severity of the
decrease in plasma sodium concentration
 Symptoms that can accompany severe
hyponatramea ( Na+ < 120meq/L ) include:
Loss of appetite
Nausea, Vomiting
Cramps, Weakness
Altered level of consciousness, seizures and
Coma

32. TREATMENT
 Identify the cause and treat
 Administration of sodium
orally
by NG tube or
 parenterally- Ringer’s lactate solution or
isotonic saline [0.9%Nacl]is given

33. HYPERNATRAEMIA
 It is defined as a plasma sodium concentration
more than 150meq/L
 Result from pure water loss, hypotonic fluid
loss or salt gain

34. Causes of hypernatraemia
1. Pure water depletion
A. Extrarenal loss
• Failure of water intake
(coma, elderly, postoperative patients)
• Mucocutaneous loss –Fever
B. Renal loss
• Diabetes insipidus
• Chronic renal failure

35. Causes of hypernatraemia
2. Hypotonic fluid loss
A. Extrarenal loss
• Gastrointestinal (vomiting,diarrhoea)
• Excessive sweating
B. Renal loss
• Osmotic diuresis (glucose, urea, mannitol)

36. Causes of hypernatraemia
2. Hypotonic fluid loss
C. Salt gain
• Iatrogenic (sodium bicarbonate, hypertonic
saline)
• Salt ingestion
• Steroid excess

37. Treatment
 Treat underlying cause
 Administration of water orally/nasogastric tube
 Administration of hypotonic sodium solution
0.3 or 0.45%
 Change in serum sodium not more than 2
mmol/L h
 Rapid rehydration can cause cerebral edema

38. POTASSIUM
 Plays an important role in cell membrane
physiology especially in maintaining resting
membrane potential and in generating action
potentials in the central nervous system and
the heart

39. POTASSIUM
 Intracellular potassium - 150meq/litre
Extracellular concentration 3.5 to 5.0mml/l
(plasma level)
 Total body potassium in a 70kg adult -.4.256
meq)
 Insulin and beta adrenergic agonists promote
potassium entry into the cell

40. HYPOKALAEMIA
 Potassium concentration (k+) < 3.0 meq/L
 Is a frequent complication of treatment with
diuretics

41. Causes of hypokalaemia
 Reduced intake
 Tissue redistribution: Insulin
therapy,alkalemia, β adrenergic agonists
 Increased loss: Gastrointestinal losses-
diarhoea, vomiting, fistulae
 Renal causes: Diuretics, renal artery stenosis,
diuretic phase of renal failure

42. Symptoms
 Anorexia, nausea
 muscle weakness, paralytic ileus
 Altered cardiac conduction:
Delayed repolarisation
Reduced height of ‘T’ wave
Presence of ‘ U’ wave
Wide QRS complexes and arrhythmias

43. Treatment of hypokalaemia
 Diagnosis and treatment of the cause
 Potassium supplements, in the form of milk,
fruit juice, tender coconut water
 Syrup potassium chloride orally -15ml
contains 20 mmol of potassium

44. Treatment of hypokalaemia count..
 Intravenous potassium chloride can be given at
a rate not exceeding o.5mmol/kg/h under
electrocardiographic monitoring
 A maximum of 200mmol/day should not be
exceeded in a 70kg individual

45. HYPERKALAEMIA
 Hyperkalaemia is defined as plasma
potassium in excess of 5mmol/L

46. Features
 Irregular slow pulse
 hypotension
 anxiety, irritability
 Paresthesia
 weakness

47. Causes
1. Impaired excretion
• Acute kidney injury (AKI),
• Chronic kidney disease (CKD):
• Hyperaldosteronism
• K ion sparing diuretics
• Patients with chronic kidney disease must be
careful of foods rich in potassium

48. Causes count..
2. Tissue redistribution
• tissue damage ( burns, trauma)
• Acidosis
• Suxamethonium
• Periodic paralysis
• Massive intravascular haemolysis

49. Causes count….
 Stored blood transfusion
 Excessive intravenous
 Potassium supplementation

50. Signs and symptoms
 Symptoms are nonspecific and include
weakness and fatigue
 palpitations or chest pain
 occasional bradycardia due to heart block or
tachypnoea from respiratory muscle weakness
 Muscle weakness and flaccid paralysis
 Depressed or absent tendon reflexes

51. Treatment of hyperkalaemia
 Calcium gluconate (10%) 10 – 30ml
 Sodium bicarbonate 1-2 mmol/kg over 10-15
minutes
 100ml of 50% dextrose with 10-12 units of
insulin over 15 -20 minutes
 Hyperventilation
 Salbutamol nebulisation
 Peritoneal or haemodialysis

52. CALCIUM
 Calcium is the most abundant mineral in the
body
 99 percent is deposited in the skeleton
 Calcium ions are important for the control of
muscular and neural activities, in blood
clotting, as cofactors for enzymatic reactions

53. HYPOCALCEMIA
 Hypocalcaemia exists when calcium level is
less than 9mEq/L
 Causes
i. Hypoparathyroidism
ii. Vitamin D deficiency
iii. Chronic renal failure
iv. hypoalbuminaemia

54. Symptoms and Signs
 Numbness and tingling sensation of fingers
 hyperactive reflexes, muscle cramps
 pathological fractures,
 prolonged bleeding time
 Chvostek’s sign

55. Treatment:
 Treat underlying cause
 Asymptomatic hypocalcaemia is treated with
oral CaCl, Ca gluconate or Ca lactate
 Tetany from acute hypocalcaemia needs IV
CaCl or Ca gluconate to avoid hypotension
bradycardia and other dysrrhythmias
 Chronic or mild hypocalcaemia can be treated
by consumption of food high in calcium

56. HYPERCALCEMIA
 Hypercalcaemia exists when the Ca2+
concentration of the ECF is above 11 mEq/L
 Features
Intractable nausea,
 vomiting and dehydration
Coma and Death

57. Causes
 Hyperthyroidism,
 Metastatic bone tumors
 Paget’s disease
 Osteoporosis
 Prolonged immobilization

58. Treatment
 IV normal saline, given rapidly with Lasix
promotes urinary excretion of calcium
 Drug therapy - Slower onset of action
i. Mithramycin - 24-48hrs - directly acts on
bones
ii. Calcitonin - 24-48hrs - inhibits calcium
reabsorption
iii. Etidronate - >3days - inhibits bone resorption

59. •THE END
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