GENERAL SURGERY FLUID AND ELECTROLYTES ACID BASE BALANCE

1. FLUID AND
ELECTROLYTES
DR. HAYDAR MUNEER
B.D.S. , F.I.B.M.S.

2. TOTAL BODY WATER (TBW)
Water constitutes approximately 50 to
60% of total body weight
muscle and solid organs have higher
water content than fat and bone
. The highest percentage of TBW is
found in newborns, with approximately
80% of their total body weight
comprised of water

4. FLUID COMPARTMENTS
1. The extracellular:
Compromise about 1/3 of total body
water(20% of body weight) and is divided
between plasma and interstitial fluid
2. The intracellular:
Compromise about 2/3 of total body
water (40% of body weight) with the
largest proportion in the skeletal muscle
mass

6. COMPOSITION OF FLUID COMPARTMENTS
 The extracellular fluid compartment is
balanced between the principal cation—
sodium and the principal anions—chloride
and bicarbonate.
 The intracellular fluid compartment is
comprised primarily of the cations,
potassium and magnesium, and of the
anions, phosphate and proteins.
 maintained by ATP-driven sodium-
potassium pumps located within the cell
membranes.

7. OSMOTIC PRESSURE
The movement of water across a
cell membrane depends primarily
upon osmosis. To achieve osmotic
equilibrium, water moves across a
semipermeable membrane to
equalize the concentration on both
sides

8. OSMOTIC PRESSURE
any change in osmotic pressure in
one compartment is accompanied
by a redistribution of water until the
effective osmotic pressure between
compartments is equal.

10. NORMAL EXCHANGE OF FLUID AND ELECTROLYTES
Fluid input
1. Exogenous 2 to 3 L
Ingested water and fluids / Ingested
food (5%)
2. Endogenous 500 ml
Oxidation of food

11. NORMAL EXCHANGE OF FLUID AND
ELECTROLYTES
Fluid output
1. Lungs ( 400 ml/24hrs)
2. Skin ( 600-1000 ml/24hrs)
3. Faeces (60-150 ml /24hrs)
4. Urine (1500/24hrs)

13. ETIOLOGY OF VOLUME DEFICIT IN
SURGICAL PATIENTS
1. Loss of gastrointestinal fluids
from nasogastric suction,
2. Vomiting,
3. Diarrhea,
4. Fistula.
5. Sequestration secondary to soft-
tissue injuries.
6. Burns.
7. Prolonged surgery can also lead
to volume deficits

14. FLUID REPLACEMENT:
A typical daily maintenance fluid
regimen would consist of a
combination of 5% dextrose with either
Hartmann’s or normal saline to a
volume of 2 litres.

16. FLUID REPLACEMENT:
 Young fit patients with normal renal and
cardiac function. Atypical regimen might
include: 1000 ml 0.9% saline over 2h;
further 1000 ml infusion of 0.9% saline over
4h each until corrected.
 Elderly patients and patients with renal or
cardiac impairment . Atypical regimen
include 1000ml 0.9% saline over 4h, 500 ml
infusion of 0.9% saline over 3-4h with
regular review of vital signs

18. ELECTROLYTES IMBALANCE:
1. Sodium: 137-147 mmol/L
Total body content 500 mmol
(44% EC, 9% IC, 47% bone)
Daily requirement:50-90 mM
/day

19. Body System Hyponatremia
Central nervous
system
Headache, confusion, seizures, coma, increased
intracranial pressure
Musculoskeletal Weakness, fatigue, muscle cramps
Gastrointestinal Anorexia, nausea, vomiting, watery diarrhea
Cardiovascular Hypertension and bradycardia
Tissue Lacrimation, salivation
Renal Oliguria
Body System Hypernatremia
Central nervous
system
Restlessness, lethargy, irritability, tonic spasms, seizures,
coma
Musculoskeletal Weakness
Cardiovascular Tachycardia, hypotension, syncope
Tissue Dry sticky mucous membranes, red swollen tongue,
decreased saliva and tears
Renal Oliguria
Metabolic Fever

21. 2. Potassium : 3.5mmol/L
98% intracellular, 75% in skeletal
muscles
Daily requirement 50 mM/day
Body system Hyperkalemia
Gastrointestinal Nausea/vomiting, colic,
diarrhea
Neuromuscular Weakness, paralysis,
respiratory failure
Cardiovascular Renal Arrhythmia, arrest
Body system Hypokalemia
Gastrointestinal Ileus, constipation
Neuromuscular Decreased reflexes, fatigue,
weakness, paralysis
Cardiovascular Arrest

23. 3. Calcium: 2.2-2.5 mmol/L
Important for blood coagulation
and neuromuscular activity
Daily requirement 5 mM/day
Body system Hypercalcemia
Gastrointestinal Anorexia, nausea/vomiting,
abdominal pain
Neuromuscular Weakness, confusion, coma,
bone pain
Cardiovascular Renal Hypertension, arrhythmia,
polyuria Polydipsia
Body system Hypocalcemia
Gastrointestinal
Neuromuscular Hyperactive reflexes,
paresthesias, seizures
Cardiovascular Renal Heart failure

24. The level of calcium is affected by:
1. Vitamin D
2. Parathyroid hormone
3. Calcitonin
4.Renal and bowel function

25. ACID – BASE IMBALANCE:
 The pH of body fluids is maintained within a
narrow range ( normal PH 7.36-7.44)
Important buffers include:
1. Intracellular proteins and phosphates
2. Extracellular bicarbonate-carbonic acid
system

29. COMPENSATION FOR ACID-BASE
DERANGEMENTS
1. Respiratory (for metabolic derangements):
Changes in ventilation in response to
metabolic abnormalities are mediated by
hydrogen-sensitive chemoreceptors found
in the carotid body and brain stem. Acidosis
stimulates the chemoreceptors to increase
ventilation while alkalosis decreases the
activity of the chemoreceptors and thus
decreases ventilation

30. COMPENSATION FOR ACID-BASE
DERANGEMENTS
2. Metabolic (for respiratory
derangements):
The kidneys provide compensation for
respiratory abnormalities by either
increasing or decreasing bicarbonate
reabsorption for respiratory acidosis or
alkalosis, respectively
Compensation does not begin for at
least 6 hours and continues for several
days.

32. ALKALOSIS: MORE THAN 7.44

33. 1. Metabolic alkalosis:
 Excessive ingestion of alkalis
 Loss of acid (vomiting)
 Cortisone excess (Cushing disease)
 Compensation by:
Retention of CO2
Excretion of bicarbonate by the kidney
 Treatment:
Remove the cause
Encourage high urine output
Correct hypokalemia

34. 2. Respiratory alkalosis:
 Due to excessive pulmonary ventilation
 Anesthesia
 High altitude
 Hyper pyrexia
 Hysteria
 Lesion of hypothalamus
 Compensation:
By increased excretion of bicarbonate (Slow)
 Treatment: Respiratory suppression

35. ACIDOSIS: LESS THAN 7.36

36. 1. Metabolic acidosis: due to:
 Increased in fixed acids:
 Formation of ketone bodies in diabetes or
starvation
 Retention of metabolites in renal failure
 Anaerobic metabolism (increase lactic acid) as in
cardiac arrest and shock
 Loss of base:
 Diarrhea
 Ulcerative colitis
 Gastro colic fistula
 Intestinal aspiration
 Compensation: by hyperventilation
 Treatment: Restoration of adequate tissue
perfusion, Bicarbonate solution

37. Respiratory acidosis
Impaired alveolar ventilation
Anesthesia and lung diseases
 Treatment:
Correct the underlying cause
Bicarbonate solution