Fluids and Electrolytes

Question 1

When is oral potassium an adequate compensation for potassium loss?

Answer 1

Those taking digoxin or anti-arrhythmic drugs, where potassium depletion may induce arrhythmias

Those whom secondary hyperaldosteronism occurs, e.g. renal artery stenosis, cirrhosis of the liver, nephrotic syndrome, and severe heart failure.

Excessive losses of potassium in the faeces e.g. chronic diarrhoea associated with intestinal malabsorption or laxative abuse.

Question 2

When should potassium levels be measured and corrected in the elderly?

Answer 2

Inadequate dietary intake

Long-term administration of corticosteroids

Question 3

When potassium salts are given, what side effects lead to poor compliance?

Answer 3

Potassium salts cause nausea and vomiting

Question 4

Acute severe hyperkalaemia (>6.5 mol/litre or with ECG changes) urgent management?

Answer 4

Treatment with calcium gluconate 10% by slow IV injection titrated and adjusted to ECG improvement, to temporarily protect against myocardial excitability.

Question 5

What does an IV injection of insulin (5-10 units) with 50 mL glucose 50% do to a person with acute severe hyperkalaemia?

Answer 5

Reduces serum-potassium concentration; this is repeated if necessary or a continuous infusion instituted.

Question 6

Which bronchodilator may reduce plasma-potassium concentration?

Answer 6

Salbutamol

Question 7

In mild hyperkalaemia or moderate hyperkalaemia, what may be used to remove excess potassium?

Answer 7

Ion-exchange resins

Question 8

Replacement of fluid and electrolytes lost through diarrhoea can be achieved by giving solutions containing? (4)

Answer 8

Sodium
Potassium
Glucose
Another carbohydrate such as rice starch

Question 9

In chronic conditions associated with mild or moderate sodium depletion, e.g salt-losing bowel or renal disease, which oral supplements may be sufficient?

Answer 9

Sodium chloride

Sodium bicarbonate

Either of the above according to the acid-base status of the patient.

Question 10

In chronic acidotic states, like uraemia acidosis or renal tubular acidosis, what can be given?

Answer 10

Sodium bicarbonate orally

Question 11

What can be given for severe metabolic acidosis?

Answer 11

Sodium bicarbonate IV

Question 12

What are the potential side effects of sodium supplements?

Answer 12

Increase blood pressure
Cause fluid retention
Pulmonary oedema
Hypokalaemia may be exacerbated

Question 13

Gastro-enteritis, diabetic ketoacidosis, blues, and ascites are examples of conditions that can cause what electrolyte depletion?

Answer 13

Sodium depletion

Question 14

Why should be given to people who are suffering with sodium depletion?

Answer 14

Sodium chloride in isotonic solution.

Question 15

Why should sodium chloride be given slowly for acute or chronic hyponatraemia?

Answer 15

To avoid the risk of osmotic demyelination syndrome.

The rise in plasma concentration should not exceed 10 mol/litre in 24 hours.

Question 16

Why could compound sodium lactate (Hartmann’s solution) be used instead of isotonic sodium chloride?

Answer 16

It may reduce the risk of hyperchloraemic acidosis

Question 17

What solution and ration are indicated when there is a combined water and sodium depletion?

Answer 17

Sodium chloride with glucose

1:1 mix of isotonic sodium chloride and 5% glucose

Question 18

What fluids should be given for combined sodium, potassium , chloride and water depletion (e.g. severe diarrhoea)?

Answer 18

Sodium chloride IV infusion 0.9% and glucose IV infusion 5% with potassium as appropriate

Question 19

Glucose solutions (5%) are used mainly to _______ _____ _______

Answer 19

Replace water deficit

Question 20

Glucose is given in regimens with calcium and insulin for the emergency management of ______________

Answer 20

• Hyperkalaemia
  and
• After correction of hyperglycaemia
• During treatment of DKA

Question 21

What is the initial treatment for the correction of severe hypokalaemia?

Answer 21

Potassium chloride with sodium chloride IV infusion, only when sufficient potassium cannot be taken by mouth.

Question 22

Why should initial potassium replacement therapy not involve glucose infusions?

Answer 22

Because glucose may cause a further decrease in the plasma-potassium concentration.

Question 23

What is sodium bicarbonate’s mechanism of action?

Answer 23

Sodium bicarb buffers metabolic acidosis and lactic buildup in the body caused by anaerobic metabolism secondary to severe hypoxia by reaction with hydrogen ions to form watch and carbon dioxide.

Question 24

What are the indications for sodium bicarbonate?

Answer 24

• Alkalinisation of urine
• Relief of discomfort in mild UTIs
• Maintenance of alkaline urine
• Chronic acidotic states such as uraemia acidosis or renal tubular acidosis
• Severe metabolic acidosis
• Removal of earwax

Question 25

What are the side-effects can occur with sodium bicarb use?

Answer 25

For removal of ear wax: Dry Ear

With IV use:

• Skin exfoliation
• Soft tissue necrosis
• Ulcer

With oral use:

• Abdominal cramps
• Burping
• Flatulence
• Hypokalaemia
• Metabolic alkalosis

Question 26

In more severe metabolic acidosis (or unresponsive acidosis to correction of anoxia or hypovolaemia), what treatment should be given?

Answer 26

Sodium bicarbonate (1.26%) can be infused over 3-4 hours with plasma-pH and electrolyte monitoring.

Question 27

In severe shock, metabolic acidosis can develop without sodium or volume depletion, in these circumstances, how should sodium bicarbonate be given?

Answer 27

A small volume of hypertonic solution, such as 50mL of 8.4% solution IV

Question 28

Why is sodium lactate IV infusion no longer used in metabolic acidosis?

Answer 28

Because of the risk of producing lactic acidosis, particularly in seriously ill patient with poor tissue perfusion or impaired hepatic function.

Question 29

What are colloids?

Answer 29

Plasma and plasma substitutes that contain large molecules that do not readily leave the intravascular space where they exert osmotic pressure to maintain circulatory volume.

Question 30

What are crystalloids?

Answer 30

Fluids containing electrolytes such as sodium chloride and glucose, a small volume of colloid is required to produced the same expansion of blood volume, thereby shifting salt and water from the extravascular space.

Question 31

Which plasma substitute can be given without regard to the recipient’s blood group?

Answer 31

Albumin solution

Question 32

What is and isn’t in albumin solution?

Answer 32

Contains:

• soluble proteins
• electrolytes

Does not contain:

• clotting factors
• blood group antibodies
• plasma cholinesterase’s

Question 33

What are the indications of albumin solution?

Answer 33

• Acute or subacute loss of plasma volume
  e. g. burns, pancreatitis trauma, and complications of surgery, plasma exchange, –
• Generalised oedema where salt and water restriction with plasma volume expansion are required
• Paracentesis of large volume ascites associated with portal hypertension

Question 34

What should Hydroxyethyl starches be used for?

Answer 34

The treatment of hypovolaemia due to acute blood loss when crystalloids alone are not sufficient.

Question 35

Name 3 macromolecular substances which are plasma substitutes and are metabolised slowly?

Answer 35

Dextran, gelatin, and the hydroxyethyl start, tetrastarch.

Question 36

When should dextran and gelatinous be used?

Answer 36

To expand and maintain blood volume in shock arising from conditions such as burns or septicaemia
Also as immediate short term measure for haemorrhage until blood is available