The document discusses fluid and electrolyte homeostasis in the human body. It defines key terms like homeostasis, electrolytes, osmosis, and body water content. It describes the characteristics, functions and normal ranges of important fluids and electrolytes like sodium, potassium, calcium and magnesium. It also discusses electrolyte abnormalities like hyponatremia, hypernatremia, hypokalemia, and hyperkalemia and their potential causes, clinical signs, and treatment approaches.

1. ABHITOSH DEBATA ,
Dept of OMFS

2.  HOMEOSTASIS
 TERMINOLOGIES
 BRIEF INTRODUCTION TO FLUID AND
ELECTROLYTES
 CHARACTERISTICS OF SPECIFIC FLUIDS
AND ELECTROLYTES
 ELECTROLYTE ABNORMALITIES
 CONCLUSION
 REFERENCES

3. HOMEOSTASIS
Is defined as maintenance of static or constant
conditions in the internal environment. - Guyton

4. 4

5. Electrolyte :
Is a substance containing free ions that behaves as an electrically conductive medium…
Osmosis :
Net movement of the solvent across the semi permeable membrane from a region of high solute
potential to an area of low solute potential.

6. Osmotic Pressure :
Force per unit area or pressure required to prevent the passage of water through a selectively
permeable membrane & into a solution of greater or equivalent concentration
Reverse Osmosis :
Solvent moving from a region of high solute conc to a region of low solute concentrate by
applying pressure in excess of the osmotic pressure.

7. Osmolarity is defined as the number of osmoles of solute per liter
(L) of solution.
NaCl solution has an osmolarity of 2 osmol/L.
Osmolality is defined as the number of osmoles of solute per
kilogram of solvent. It is expressed in terms of osmol/kg or
Osm/kg.

8. Body fluids
Water constitutes an average 50% to 70% of the total body weight
Young males - 60% of total body weight
Older males – 52%
Young females – 50% of total body weight
Older females – 47%
Variation of ±15% in both group is normal
Obese have 25 to 30% less body water than lean people.
Infants - 75 to 80%
Child - 65% at one year of age

11. Daily loss of body water
Insensible water loss
Cannot be precisely regulated

12. Distribution of body fluids

13. Difference betwEEn ecf & icf
EXTRACELLULAR INTRACELLULAR
Main constituent – Na+ K+ , MG , sulfate , phosphate
Chief anion – CL- Hpo2 , sulfate ions
Traces of k , ca , mg ,ph,s Traces of NA+ ,CL- , no CA
15 - 20 litre in an avg adult(70kgs) 25 – 40 litre in an avg adult(70kgs)

14. To summarize in 70Kg male
TBW – 42 lts
ICF – 28 lts
Extra vascular fluid – 10.5lts
ECF – 14 lts
Intravascular fluid – 3.5lts
Blood volume = Plasma volume + RBC volume
= 8% of BW = 5.6 lt approx.

15. MOVEMENT OF BODY FLUIDS
- Diffusion
- Osmosis
- Active transport

16. Water balance
Intake Regulation
Driving force for intake .........thirst
 of 10% plasma volume
↓
Dry mouth
↓
hypothalamic thirst centre
↓
Drink

17. Anti-diuretic hormone (vasopressin)

18. Inappropriate Stimuli of ADH Release
•Narcotics
•Nicotine
•Vincristine
•Carbamazepine
•Chlorpropamide

19. 19

20. Input & Output of water

21. Sodium –Potassium Pump

23. Clinical Evaluation
Changes in BW…
Water loss Degree of Dehydration
4% of body wt Mild
6% “ “ Moderate
8% “ “ Severe
Normal urinary output
Adult 0.5-2cc/kg/hr
Child 2cc/kg/hr

24. FLUIDTHERAPY

25. 0.9% NaCl (normal saline) isotonic
0.25% NaCl hypotonic
0.45% NaCl hypotonic
2.5% dextrose hypotonic
Lactated Ringer's solution isotonic
D5W (acts as a hypotonic
isotonic
solution in body)
D5 NaCl hypertonic
D5 in Lactated Ringer's hypertonic
D5 0.45% NaCl hypertonic

27. Fluid therapy
Route……

28. Fluid types
Crystalloids and colloids
3ml of crystalloids = 1ml of colloid (blood for intravascular
replacement)
Crystalloids
1. Molecular wt <8000 daltons
2. Replaces mainly extracellular volume
E.g.
a. Normal saline.
b. 5% dextrose
c. Ringer’s lactate
3. Shorter intravascular half life
4. In trauma it stabilizes the haemodyNamics in 3 hrs

29. Colloids
1. Molecular wt > 8000 daltons
2. Replace intravascular volume
E.g.
a. Serum albumin.
b. Human plasma.
c. Synthetic plasma expanders.
i. Gelatin solution
ii. Dextrans
3. Longer intravascular half life
4. In trauma it stabilizes the haemodyNamics in 2 hrs

30. IV fluids
0.9%Sodium Chloride –
iso osmolar with plasma and ECF hence Called normal saline…
serves a good replacement solution for ECF volume deficient…
chloride content - higher than that of plasma infusion → too much of
normal saline may produce hyperchloraemic acidosis…
IndiCation : ECF def in the presence of hyperNatremia, hypochloremia
& metabolic alkylosis…

31. Dextrose 5%in water
It provides 50gms of dextrose / l.
It is slightly hypertonic to plasma
after infusion dextrose is metabolized→ water is left in the ECF…
too much of 5% dextrose may Cause dilution and hypotonicity of ECF
and water loading, if kidneys are not functioning normally.
100ml --- dextrose 5gm
Dextrose 5%with 0.9% of saline.
Its twice as hypertonic as plasma…
However within a few hours glucose is used and there is no signifiCant
change in the plasma tonicity…
100ml ----dextrose 5 gm, NaCl .9 gm, water

32. Lactated ringers solution.
This is slightly hypo osmolar compared to plasma & contains Na, K, Ca,
Cl & Lactate...
Its good substitute for gastrointestiNal and other ECF fluid deficits in
the absence of gross abnormalities of concentration
Used in correcting metabolic acidosis….
Should not be given in patients with liver diseases and in presence of
lactic acidosis.

33. Ringers acetate solution.
- slightly hypo osmolar to plasma…
- main use is as a replacement for ECF deficits in patients with
damaged liver or lactic acidosis..
- helps in correction of mild to moderate metabolic acidosis.
0.45% sodium chloride in 5% dextrose solution
- It is used as mainteNance fluid in postoperative period.
- Provides sodium for reNal adjustment of sodium concentration in the
serum.
- Potassium may be added to be used for mainteNance requirements
in uncompliCated pt requiring only a short period of parenteral fluids.

34. Hypertonic saline solution
1.8% sodiumchloride
- Indicated in correction of pts with symptomatic hyponatraemia who
Can not be given too much of water volume due to oliguria or anuria.
7.2-7.5% sodium chloride
- Studies have shown that even with 50% blood loss a small volume of
7.2-7.5% NaCl restores the Cardiac output and blood pressure within
one minute.
- This saline is given through a peripheral vein very fast over 2 to 5
mins. And this results in rise in the plasma sodium level and plasma
osmolality Causing a shift of body water in the vascular tree

35. Colloid solutions
Human plasma
Used for resuscitation of shock patient and for
mainteNance of I.V. fluid therapy
it has a composition and osmolality similar to ECF.
Human Albumin
20% purified human albumin is commercially available. Its volume
expansion Capacity is 400 per cent.
Rarely, aNaphylactoid reaction has been reported with albumin and
may Cause post resuscitation hypotension.

36. The usual volume of fluid intake necessary.
The choice of IV fluid type.
Three electrolytes considered when choosing an IV solution.

37. In general after dentoalveolar surgery IN otherwise healthy patient
requires a relatively physiologic IV solution with some calories during
and after surgery, which can be provided IN combination WITH
crystalloid solutions, such as 5% dextrose in a 0.45% sodium chloride
solution to which 20 mEq of potassium chloride per liter MAY BE
added.

38. ClassifiCation of Body Fluid Changes/disorders
Disorders in the fluid balance are Classified in three general Categories.
Disturbances of
- Volume.
- Concentration.
- Composition.

39. Causes of ECF deficit
1. Loss of GI fluids due to:
a. Vomiting.
b. Diarrhea.
c. Nasogastric suction.
d. Fistular draiNage.
2. soft tissue injuries and infections.
3. IntraabdomiNal and Intraperitoneal inflammatory processes.
4. Burns.
5. Insensible losses
6. Sweat.

40. Causes of ECF excess
1. Iatrogenic
2. Secondary to reNal insufficiency
3. Cirrhosis
4. Sodium retention
5. Mineralocorticoids
6. NSAIDS

41. CAUSES OF VOLUME DEFICIT
• Failure to absorb or reabsorb water.
• Complete sudden cessation of intake.
• Prolonged diminished intake.
• Difficulty or inability to take orally.
• Loss from GIT via vomiting and kidneys.
•Soft tissue injuries burns.

42. SIGNS OF MODERATE VOLUME DEFICIT : ECF LOSS
EARLY SIGNS
CNS : Sleepiness,cessation in usual activity, anorexia, thirst
CVS : Orthostatic hypotension, Tachycardia, weak thready pulse
GIT : progressive decrease in food consumption,
AFTER 24 HOURS
TISSUE SIGNS :
Soft ,small tongue with longitudinal wrinkling, Dry mucus membrane ,
dry cracked lips

43. SIGNS OF SEVERE VOLUME DEFICIT :
EARLY SIGNS
•CNS : decreased tendon reflexes, anesthesia of extremeties,
•stupor, coma
•CVS: hypotension, distant heart sounds, absent peripheral pulse
•GIT : nausea , vomiting refusal to eat
AFTER 24 HOURS
TISSUE SIGNS: Eyeballs sunken , atonic muscles

44. SPECIFIC MANAGEMENT……

45. CAUSES OF FLUID LOSS IN SURGICAL PATIENTS
•Increased loss from lungs after anesthesia
•Fistulae
• In soft tissue injuries & infections
•Burns
•External loss of fluids
•internal redistribution of ECF in nonfunctional spaces

46. CLINICAL MANIFESTATION
•Skin pallor
•Cold extremities
•Weak and rapid pulse
•Hypotension
•Oliguria
•Decreased levels of consiousness

47. MANAGEMENT
Treat the cause
1. For burns and tissue injuries large volume of isosmolar IV fluid is
administered
2. Albumin is administered for protein deficit
3. IV fluid intake is maintained after major surgery to maintain
kidney perfusion
4. Pericardiocentesis if pericarditis is the cause
5. Paracentesis for ascitis

48. Concentration changes
 The serum sodium level/Conc. is used to estimate the total body
fluid osmolality.
 Even though the sodium ions are largely confined to the
extra cellular compartment, its level/Conc. reflects total body
osmolality.

49. Compositional changes
Compositional abnormalities of importance include changes in
Acid – base balance and concentration changes of calcium,
Potassium and magnesium.

50. Methods to calculate the rate of fluid infusion

52. • 4/2/1 Rule
•Maintenance of fluids for 24 hours :
100/50/20 rule

53. The Electrolyte abnormalities include –
 Sodium abnormalities
 Potassium abnormalities
Calcium abnormalities
 Magnesium abnormalities

54. Na + (Sodium)
Function:
Most important ion in regulating ECF volume and thereby
maintaining BP
Important in nerve and muscle function

55. Serum Na+
Normal daily intake: 100 mEq/lt
Causes of Hyponatremia

56. Causes of hyponatremia with increased extracellular
volume
-Heart failure.
-Liver failure.
-Oliguric renal failure
-Hypoalbuminaemia
-Hyperglycemia
-Hyperlipidemia
Each 100mg/dl raise in blood glucose
results in decrease in serum sodium
concentration of about 1.6 to 3mEq /Lt

57. Clinical Signs and Symptoms
Symptoms rarely develop unless serum sodium drops 120 to 125mEq/Lt

58. Treatment
Determine if hyponatremia acute
Chronic
Acute serum sodium <110-115meq/lt
Symptomatic - seizures
coma
Rapid correction- Till serum sodium 120-125meq/lt
If it is asymptomatic gradual correction over 48 hrs

59. Hypernatremia
Clinical manifestations of hypernatremia
 Thirst
 Lethargy
 Neurological dysfunction due to dehydration of brain cells
 Decreased vascular volume

60. Correction of Hypernatremia
Asymptomatic: 5% dextrose in H2O
0.45% saline preferable in coma. Very large volumes of 5litres a day may
be needed to be given.
Symptomatic:
1. 0.9% saline to correct volume deficit
2. Correct over a period of 48 hrs as rapid correction may lead to
cerebral edema.

61. Potassium
Functions :
Regulates fluid, ion balance inside cell
Ph balance
Maintains cell integrity

62. Serum Potassium
98% located in intracellular compartment.
Normal daily intake 40-60mEq/Lt.
Over 85% is excreted in urine and stool.

64. Hypokalemia
Persistent reduction of serum potassium below 3.5 meq/l
.
Causes
•Decreased intake of k+
•Increased k+ loss: renal / non renal
ochronic diuretics
oacid/base imbalance
otrauma and stress
oincreased aldosterone
oredistribution between icf and ecf
oMetabolic alkalosis

65. Hypokalemia in surgical patients
Excessive renal secretion
Movement of potassium in cells
Prolonged administration of k- free parentaral fluids
Continued loss of k through urine
Loss of GIT secretions

66. Clinical manifestations
•Gradual onset of drowsiness, with difficulty in rousing and slow
opening of the eye
•Slow slurred speech
•Neuromuscular disorders
–Weakness, flaccid paralysis, respiratory arrest, constipation
•Dysrhythmias
•Postural hypotension
•Cardiac arrest

67. Clinical features
BP is low and slow pulse rate
Warm and dry skin
Reddish flushed face
Increased thirst

68. Treatment
•Increase k+ intake, but slowly, preferably by foods
•Oral administration of potassium salt
•Potassium chloride effervescent tab 2gm 8th hrly
•In case of coma patients and severe vomiting-
•Administration of IV fluids- ISOLYTE G, ISOLYTE M
•Maintain within 7 mEq/L
•Assure adequate urine out put

69. HYPERKALEMIA
•Serum k+ > 5.5 meq / L

71. Clinical signs and symptoms
- Cardiac
1. Peaked T wave
2. QRS widening.
3. St depression
4. Bradycardia
5. Ventricular fibrillation
- Neuromuscular
1. Weakness
2. Paresthesia
3. Respiratory failure

72. Treatment:
Immediate
If potassium levels greater than 7mEq/L
1.Protect myocardium
10ml of 10% calcium gluconate given over
2-3 minutes in the presence of ECG changes

 In potassium level in 1hr
If no response second dose can be repeated

73. 2. Drive potassium into the cells
10 units of insulin + 5% dextrose in water I.v. administered over 5
minutes decreases serum potassium levels in 30 mins and last for
several hours.
Regular check of blood glucose and potassium
Repeat as necessary
3. 1.26% Sodium bicarbonate –
Can be given with 5% dextrose in water.
If ECG changes still present – repeat dose 15 mins after first dose

74. CALCIUM
Normal serum level : 9.5 – 11 mg/dl
1000 -1200 gm found in bones
Daily intake : 1- 3 gm
Excretion : git,renal

75. HYPERCALCEMIA
Ca > 15 mg/ml
Results from:
Hyperparathyroidism
Hypothyroid states
Renal disease
Excessive intake of vitamin D
Milk-alkali syndrome
Certain drugs
Malignant tumors – hypercalcemia of malignancy
Tumor products promote bone breakdown
Tumor growth in bone causing ca++ release

76. •EFFECTS:
–Initially GI symptoms
–Nausea, abdominal cramps
•Diarrhea / constipation
–Many nonspecific – vague pain
–Fatigue, weakness, lethargy
–Muscle cramps
–Bradycardia, cardiac arrest
–Metastatic calcification
–Increases formation of kidney stones and pancreatic stones
–Finally stupor & coma

77. Treatment
A.Measures to↑ urinary execretion of ca
0.9 % nacl followed by frusemide cautiously
Haemodialysis
B. Measures to ↓ ca reabsorption
Biphosphontes, calcitonin
C. Meassures to ↓ intestinal absorption
Glococorticosteroids, oral phosphates

78. Hypocalcemia
Numbness tingling sensation in the circumoral region and the tip of the
fingers and toes
Convulsions in severe cases
Diagnosis:
Chvostek’s sign
Trousseau’s sign
Treatment
Iv calcium for acute
Oral calcium and vitamin d for chronic cases

80. Acute management-
10 % ca gluconate 10 to 20 ml slow i.V. Over 10 mins
If i.V. Ca doesn’t relieve tetany, rule out hypomagnesemia
Long term management-
Rx underlying etiology
Ca supplements
Vitamin d supplements

81. MAGNESIUM
4th most common cation in ecf
2nd most common cation in icf
Serum level : 1.8 to 3 mg/l
Function: normal contractility of muscle and excitability of neuronal
tissues
•Normal daily intake is 20 to 25 meq / day
•8 meq/day is absorbed and excreted in urine

82. Hypomagnesemia
Signs and sypmtoms: muscular tremors, hyperactive deep tendon
reflexes
Magnesium deficiency
Parenteral administration of magnesium chloride or sulphate
solution
Monitor heart rate, BP, respiration and ECG for signs of
toxicity
Followed by 10 to 20 mEq of 50% of magnesium sulphate
solution daily IM or IV

83. Hypermagnesemia
Hypermagnecaemia is extremely rare and is only seen in severe renal
insufficiency more so when renal dialysis is carried out
Occurs when magnesium containing antacids and laxatives are used in
patients with impaired renal function
Burns and massive trauma
Clinical features
Hypoactive deep tendon reflexes, shallow and slow respirations
lethargy, weakness
Ecg changes – increased pr interval, widened qrs complex and elevated t
wave.
Gradual muscular paralysis fallowed by coma---death due to cardiac or
respiratory arrest

84. TREATMENT
Withhold administration of exogenous magnesium
Slow administration of 5 to 10 mEq of calcium chloridE.
Haemodialisis.

85. ACID BASE BALANCE

86. Metabolic acidosis
A pH under 7.1 is an emergency, due to the risk of cardiac arrhythmias, and may
warrant treatment with intravenous bicarbonate.
Bicarbonate is given at 50-100mmol at a time under scrupulous monitoring of the
arterial blood gas readings.
Dialysis may clear both the intoxication and the acidosis.

87. Metabolic alkalosis
The management of metabolic alkalosis depends primarily on the underlying
etiology and on the patient’s volume status.
In the case of vomiting, administer antiemetics, if possible. If continuous gastric
suction is necessary, gastric acid secretion can be reduced with H2-blockers or
more efficiently with proton-pump inhibitors.
In patients who are on thiazide or loop diuretics, the dose can be reduced or the
drug can be stopped if appropriate. Alternatively, potassium-sparing diuretics or
acetazolamide can be added.

89. Depends on the
1.Preoperative hydration status
2.Length of npo
3.Normal maintenance needs
4.Replacement of “third space” losses (open belly, hot lights, extensive
dissection of tissues)
5.Replacement of blood loss
6. Fluid shift

90. EFFECT OF ANESTHESIA ON FLUID BALANCE
General anesthesia produces vasodilation and some degree of
myocardial contractility (usually overcome by sympathetic drive induced
by the surgical stimulus)
 Mechanical ventilation can increase evaporative loss if gases are not
adequately humidified, which is often the case during long Operating
procedures.
Other factors, including increased intrathoracic pressure brought about
by mechanical ventilation, a stress response to surgical stimulus, or the
prone position, may lead to increased ADH production and decreased
urine output.

91. Monitor :
Vital signs
Urine output
Acid-base status

92. PREOPERATIVE CORRECTIONS
1 ) correction of hypovolemia
2 ) correction of other disorders
CORRECTION OF HYPOVOLEMIA
Causes : vomiting , blood loss, nasogastric suction, fever,
hyperventilation, diuretic therapy, etc
Problems : ↓ o₂ carrying capacity, ↑ed risk of tissue hypoxia &
development of organ failure , risk of severe hypotension.

93. INTRAOPERATIVE FLUID MANAGEMENT
Roughly calculated as-
Correction of fluid deficit due to starvation +
Maintenece required for period of surgery +
Loss due to tissue dissection or haemorrhage

94. CORRECTION OF FLUID DEFICIT
•Volume to be replaced =
duration of starvation ( hrs) * 2ml/kg body weight
•Usually corrected by –
• 5% dextrose
•Half of calculated dose in 1st hr followed by remaining half over next 2
hrs

95. MAINTENCE VOLUME
calculated as –
duration of surgery ( hrs) *2 ml/kg body weight or
rate of infusion = 2ml/kg /hr
INTRAOPERATIVE FLUID LOSS
fluid loss d/t tissue dissection & haemorrhage in different types of
surgeries :
Type Fluid volume (ml/kg/hr)
Least trauma nil
Minimal trauma 4
Moderate trauma 6
Severe trauma 10

96. Least trauma :
Hypotonic maintence fluid, dextrose , 2ml/kg/hr
Minimal trauma :
Tonsillectomy, nasal septal repair,plastic surgery
6 ml/kg/hr; balanced salt solution for period of surgery
Moderate trauma
procedures of extermities etc
8 ml/kg/hr of ringer’s lactate or isotonic saline
Severe trauma
Radical neck dissection etc
12 ml/kg/hr ringer’s lactate or isotonic saline

97. CAUSES OF HYPOVOLEMIA IN POST OPERATIVE PATIENTS
Inadequate correction of starvation
Inadequate maintenance in intra operative period
Intra operative blood loss & fluid loss
Excessive loss due to hyperventilation, hypermetabolism & pyraxia
Lengthy operation
Environmental factors - summer

98. ROUTINE POST OPERATIVE IV FLUID FOR FIRST THREE DAYS
First 24 hrs – 2 liters 5% dextrose
or 1.5 lit 5% dextrose + 500 isotonic saline
Second post op day - 2 liters 5% dextrose + 1lit 0.9 % saline
Third post op day – similar fluid + 40 – 60 mEq potassium/day
may require modifications depending upon clinical situations