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.
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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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
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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
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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
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plasma
ICF
Interstitial
fluid
Capillary
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
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
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
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