PRINCIPLES OF FLUID

1
PRINCIPLES OF FLUID ELECTROLYTE BALANCE IN
SURGICAL PATIENTS
2
NORMAL DAILY LOSSES AND REQUIREMENTS FOR FLUIDS
AND ELECROLYTES

• Volume Na K
• ML mmol mmol
• Urine 2000 80
  60
• Insensible losses 700 -
  -
• Faeces 300 -
  10
• Minus endogenous 300 -
  -
• Water
• Total 2700
  80 70

3
ASSESSING LOSSES IN THE SURGICAL PATIENT

• INSENSIBLE FLUID LOSSES
• EFFECT OF SURGERY
• The stress response
• Third-Space losses
• Loss from the gastrointestinal tract

4
INTRAVENOUS FLUID

• 5 DEXTROSE
• 0.9 NaCl
• RINGERS LACTATE (HARTMANNS SOLUTION)
• HAEMACCEL (SUCCINYLATED GELATIN)
• GELOFUSINE (POLYGELINE GELATIN)
• HETATARCH
• HUMAN ALBUMIN SOLUTION 4.5 (HASPPF)

5
PROVISION OF NORMAL 24-HR FLUID ELECTROLYTE
REQUIREMENTS BY INTRAVENOUS INFUSION

• Intravenous fluid Additive Duration
• 500 ml 0.9 NaCl 20mmol KCl 4hr
• 500 ml 5 Dextrose -
  4hr
• 500 ml 5 Dextrose 20 mmol KCl 4hr
• 500 ml 0.9Dextrose - 4hr
• 500 ml 5 Dextrose 20 mmol KCl 4hr
• 500 ml 5 Dextrose -
  4hr

6
AETIOLOGY OF HYPER AND HYPONATRAEMIA

• Hyponatraemia
• -------------------
• - Low extracellular fluid volume
• Volume depletion
  (vomiting,diahrrhoea,burns,decreased fluid
  intake)
• salt losing renal disease
• Hypoadrenalism
• diuretic use
• - Normal extracelluler fluid volume
• hypothyroidism
• SIADH
• Increased extracellular fluid volume
• excessive water administration
• excessive mannitol use
• cardiac failure
• cirrhosis
• nephritic syndrome
• renal failure

• Hypernatraemia
• -------------------
• Reduced intake
• fasting
• nausea and vomiting
• ileus
• reduced conscious level
• Increased loss
• Sweating (pyrexia,hot environment)
• respiratory tract loss(increased
  ventilation, administration of dry gases)
• administration of dry gases
• burns
• Inappropriate urinary water loss
• Diabetes inspidus(pituitary or nephrogenic)
• Diabetes mellitus
• Excessive Sodium load (hypertonic fluid,
  parenteral nutrition)

7
CONSEQUENCES OF HYPER AND HYPOKALEMIA

• HYPERKALEMIA
• Arrythmias(broad-complex rhythms,bradycardia,hear
  t block,ventricular fibrillation)
• Muscle heart block
• Ileus
• Hypokalemia
• ECG changes
• Ectopic beats
• Muscle weakness

8
MANAGEMENT OF SEVERE ACUTE HYPERKALAEMIA (K gt
7mmol/L)

• Identify and treat cause
• 10 20 mL intravenous 10 calcium chloride over
  10 min in patients with ECG abnormalities
• (reduced risk of ventricular fibrillation)
• 50 mL 50dextrose plus 10 units short acting
  insulin over 2-3min
• Monitor plasma glucose and K over
  next30-60 min)
• Regular Salbutomol nebulizers
• Consider oral or rectal calcium
• Resonium (ion exchange resin),although this is
  more effective for non-acute hyperkalaemia.
• Haemodialysis for persistent hyperkalemia

9
ACID BASE BALANCE

• METABOLIC ACIDOSIS
• METABOLIC ALKALOSIS
• RESPIRATORY ACIDOSIS
• RESPIRATORY ALKALOSIS
• MIXED PATTERN OF ACID-BASE IMBALANCE

10
COMMON CAUSES OF METABOLIC ACIDOSIS IN THE
SURGICAL PATIENT

• LACTIC ACIDOSIS
• Shock (any causes)
• Severe hypoxaemia
• Severe haemorrhage/anaemia
• ACCUMULATION OF OTHER ACIDS
• Diabetic Ketocaidosis
• Acute Renal Failure
• INCREASED BICARBONATE LOSS
• Diahrroea
• Intestinal Fistulae
• Ureterosigmoidostomy

11
COMMON CAUSES OF METABOLIC ALKALOSIS

• LOSS OF SODIUM AND WATER
• Vomiting
• Aspiration of gastric secretions
• Diuretic administration
• HYPOKALEMIA

12
CAUSES OF RESPIRATORY ACIDOSIS

• Excessive opiate administration
• Pulmonary complications e.g Pneumonia

13
CAUSES OF RESPIRATORY ALKALOSIS ENCOUNTERED IN
SURGICAL PRACTICE

• Hyperventilation during mechanical ventilation
• Pain
• Apprehension/hysterical hyperventilation
• Pneumonia
• Central nervous system disorders(meningitis,enceph
  alopathy)
• Septicaemia

14
Principles of fluid and electrolyte balance in
surgical patients

• Discussions

15

• 1. What are the normal values or serum sodium,
  potassium, creatinine and urea?
• 2. What are the normal basal requirements for
  water, sodium and potassium?
• 3. How can this be provided in a patient who is
  fasting?
• 4. How is fluid retained in the intravascular
  compartment?
• 5. What might cause it to leak out?
• 6. In clinical practice, it is often desirable to
  "expand" the intravascular compartment. Why might
  this be desirable and how could it be done?
• 7. What are the clinical symptoms and signs of
  fluid depletion? How can the severity of fluid
  depletion be assessed?
• 8. How can clinicians assess the patients
  response to resuscitation in severe fluid
  depletion?
• 9. What biochemical disturbance might you expect
  in a patient with gastric outlet obstruction who
  has been vomiting for several days before
  admission?
• 10. What biochemical abnormalities might you
  expect in a patient who has had excessive
  diarrhoea and who has been drinking large amounts
  of water because of thirst? (If a house officer
  inadvertently prescribed too much 5 dextrose and
  not enough N Saline, you would find the same
  effect)
• In patients with massive burns, fluid losses are
  impossible to measure. How might you assess fluid
  requirements?