This document discusses fluid and electrolyte balance. It begins by outlining the distribution of total body water and average daily water intake and output in adults. It then provides guidelines for calculating daily fluid requirements in children and adults. Various isotonic intravenous fluids are listed that can be used for fluid replacement based on electrolyte needs. Normal ranges and causes of electrolyte imbalances such as hyponatremia, hypernatremia, hypokalemia, and hyperkalemia are described. Treatment approaches for correcting electrolyte abnormalities are also outlined.

1. Fluid and Electrolytes
Dr. Md. Nazmus Sakib
Junior Consultant
Department of Surgery
Email-sakibs23@gmail.com

2. Fluid
Fig: Distribution of total body water in a 70 kg man. DCT- Dense connective
tissue, ECF- Extra cellular fluid, ICF- intracelluar fluid, TCW- Transcellular
fluid.

3. Average daily water balance for a sedentary
adult
Input (ml) Output (ml)
Drink 1500 Urine 1500
Food 750 Faeces 100
Metabolic 350 Lung 400
Skin 600
Total 2600 Total 2600

4. Water requirement for children
• First 10 kg ---- --100 ml/kg/day
• Second 10 kg---- 50 ml/kg/day
• Each subsequent kg---- 20 ml/kg/day
In case of adult average requirement is 30-40 ml/kg/day

5. Interactive session
 Calculate the daily fluid requirement of a 25 kg
weight child.
 Calculate the fluid requirement of a 70 kg male
patient.

7. During prescribing fluid we should keep in mind
• Basal requirement
• Pre existing dehydration and electrolyte loss
• Continuing abnormal loss over and above basal requirement
Commonly used isotonic fluids are
Normal saline (0.9%)
5% dextrose
Hartman’s solution
Dextrose 4% - Saline 0.18%

8. Normal osmolality of ECF is 280-295 mOsm /kg.

9. The nature and volumes of fluids are determined by:
• A careful assessment of the patient including pulse, blood
pressure and central venous pressure, urine output, urine and
serum electrolytes and haematocrit.
• Estimation of losses already incurred and their nature: for
example, vomiting, ileus, diarrhoea.
• Estimation of supplemental fluids likely to be required in view
of anticipated future losses from drains, nasogastric tubes or
abnormal urine or faecal losses.

10. • When an estimate of the volumes required has been made, the
appropriate replacement fluid can be determined from a
consideration of the electrolyte composition of gastrointestinal
secretions.
• A typical daily maintenance fluid regimen would consist of a
combination of 5% dextrose with either Hartmann’s or normal
saline.

11. Hypo/Hypernatraemia
• Normal Na+ level is 135-145 mmol/L
• Hyponatraemia < 135 mmol/L
• Hypernatraemia > 145 mmol/L
• Causes of hyponatraemia
 Inadequate intake
 GI sodium loss- Vomiting, diarrhoea, external fistula
Excessive sweating, burn
Diuretics
SIADH
Third spacing of fluid- bowel obstruction, pancreatitis

12. Clinical features of hyponatraemia
• Fatigue
• Dizziness on standing
• Postural hypotension
• Low JVP
• Lethargy
• Confusion
• Coma

13. • Correction of hyponatraemia= 0.6 x Weight in kg x Deficit
• Identify and correction of cause
• Options for correction
Orally Tab. NaCl 300 mg
Infusion 0.9% NaCl
Infusion 3% NaCl

14. Causes of hypernatraemia
• Excessive administration of Na containing fluid
• Diabetes insipidus
• Impaired renal function
• Primary and secondary hyperaldosteronism
• CCF, cirrhotic liver disease, nephrotic syndrome

15. Clinical feature
• Restlessness
• Thirst
• Irritability
• Hyper reflexia
• Intra cranial haemorrhage

16. Treatment
• Restoration of intravascular volume.
• Replace the ongoing water loss
• Correction of excess Na according to concentration. If the
condition has developed quickly correct it with appropriate
volume of hypotonic fluid rapidly.
• If the condition has developed slowly correct it slowly.

17. Hypokalaemia
• Major intracellular cation.
• Develops when K+ level is below 3.5 mmol/L
• Clinical feature:
– Asymptomatic when mild (3-3.3 mmol/L)
– Muscular weakness
– Tiredness
– Cardiac effect: ventricular ectopic, arrythmia
– Decrease reflex
– Paralytic ileus

18. Hypokalaemia (Cont…)
ECG
 Flattened T wave
 ST depression
 U wave

19. Causes
 Reduced potassium intake
 Vomiting, diarrhoea, bowel obstruction, laxative abuse
 Alkalosis
 Insulin excess,
 Primary and secondary hyper aldosteronism
 Diuretics

20. Treatment
• Identify the cause
• Correction of deficit
• Maintenance of daily requirement
For mild hypokalemia
• Give potassium containing fruits
• Oral correction by Syp. KCl

21. ***Role of ‘40’ for intravenous correction
 Urine output not less than 40 ml/hour
 Not more than 40 mmol added to 1L
 Not faster than 40 mmol/hour

22. Hyperkalaemia
Causes
• Acedosis
• Insulin deficiency
• Severe hyperglycemia
• Hemolysis, rhabdomyolysis
• Renal failure
• Drug-NSAID, ACE inhibitor, spironolactone
• Addisons disease

23. Clinical feature
• Muscle weakness
• Respiratory failure
• Decrease urine output
• Decrease cardiac contractility

24. ECG
• Wide flat P wave
• Prolonged PR interval
• Wide QRS complex
• Tall peaked T wave

25. Treatment
• Stabilize cell membrane potential by IV calcium gluconate
• Shift potassium into cell
– Inhaled β2 agonist (sulbutamol)
– IV glucose and insulin
– IV sodium bicarbonate
Remove potassium from body
 IV frusemide
 Dialysis

26. Thank You