W10 Practise lecs on Nutrition (SG)

Question 1

Normal physiology:
Fluid intake and output

Answer 1

*Intake is controlled by thirst; excretion is controlled by ADH/vasopressor → water reabsorption
*Total fluid intake for adults: 25-30mL/Kg/day
*Urine output: approximately: 0.5-1mL/ kg/hour

Insensible losses
*Perspiration ~900mL/day
*Exhaled moisture from lungs ~400mL/day
*Water lost through faeces ~200mL/day

Question 2

Assess the patient-algorithm 1

Answer 2

Fluid balance
blood pressure, heart rate
Capillary refill time
NEWS
Passive leg raising
Serum electrolytes

Question 3

Hypovolaemia Symptoms:

Answer 3

HR- Tachycardia
BP- HYPOtensive
Jugular venous pressure- Decreased
Mucous membrane- Dry
Peripheries- Cool to touch
Skin tugor (elasticity)- Decreased, sunken eyes
CRT- Prolonged
Daily weight- Weight loss

Question 4

Hypervolaemic (Fluid overload) Symptoms:

Answer 4

HR: Tachychardia
BP: HYPERtensive
Jugular venous pressure- Increased
Peripheries- Warm to touch, oedematous
Skin turgor (elasticity)- Increased, peripheral or pulmonary oedema
Daily Weight- Weight gain

Question 5

Physiology in dehydration:

Answer 5

Sepsis- Vasodilation
Trauma- Major blood loss
Severe burns- Loss of plasma
Vomiting & Diarrhoea- Loss of electrolytes

Question 6

Physiology in fluid overload
Terminology for where fluid overload occurs:

Answer 6

*The third extravascular space= non-
functional collection in interstitial space
developing in edema
*Peritoneal cavity→ ascites
*Pleural cavity → pleural effusion
*Pericardial cavity → pericardial effusion
*Joints → joint effusion

Question 7

Types of fluids: CRYSTALLOID- SMALLER MOLECULES

Answer 7

Water with added salts and glucose
* 1L of 0.9% NaCl (Iso)
* 1L of 5% glucose (hyper)
* 0.18% sodium chloride in 4%
glucose (hypo+hyper)
* Hartmann’s solution (isotonic)

Question 8

Types of fluids: Plasma-lyte 148 (Iso) 140mm

Answer 8

Larger molecules which remain in intravascular space for longer thus theoretically aids fluid retention

Human albumin- For patients with decompensated liver disease. Albumin increases plasma volume through oncotic pressure drawing in and retaining fluid (anaphylaxis risk)

Question 9

Tonicity and Osmolality: Definitions

Answer 9

• Solvent: substance that can dissolve a solute → dissolving sugar in coffee
• Isotonic fluids have the same concentration of solutes as in plasma
• Osmolality is measure of solute concentration per unit mass of solvent. It is critical this matches blood plasma (mOsm/kg) →grams of sugar dissolved in kilograms of coffee
• Osmolarity is the measure of solute concentration per unit volume of solvent (mOsm/L) → grams of sugar dissolved per Litre of coffee

Question 10

What should be used for fluid resuscitation?

Answer 10

1. Isotonic fluids should be used for fluid resuscitation
   * Prescribed as boluses to rapidly correct fluid status (fluid challenge):
   * 500mL over 15mins stat, reassess and prescribe and Rx 250-500ml again as needed (three- four times)
   * Use crystalloids that contain sodium in the range 130–154 mmol/L
   * Consider human albumin solution 4–5% for fluid resuscitation only in patients with severe sepsis.
2. Passive leg raise
   * Concerns about ability of the heart to respond to fluid challenge
   * Patient lying flat, raise legs >45 degrees →haemodynamic improvement
   →volume replacement
   * If patient deteriorates → fluid overload

Question 11

Algorithm 3- Routine Maintenance

Answer 11

• 25-30mL/kg/day of water (limit to 2.5L if possible)
• 1mmol/kg/day of Na+, K+, Cl-
• 50-100g/day glucose (glucose 5% contains 5g/100mL)
• Give less fluids in the older patients, cardiac failure or renal impairment

Question 12

Algorithm 4- REPLACEMENT and REDISTRIBUTION

Answer 12

• Replace electrolytes and address fluid losses
• Seek expert help if patients have a complex fluid and/or electrolyte redistribution issue or imbalance, or significant comorbidity
• Reassess the patient

Question 13

What are the 5Rs of Fluid Maintenance?

Answer 13

Resuscitation
Routine Maintenance
Replacement and redistribution
Reassessment

Question 14

Potassium 3.5 – 5.3 mmol/L

Answer 14

• Potassium is the primary intracellular cation
• Has a vital role in cell metabolism
• A small amount is in extracellular fluids and is maintained within a narrow range
• Sodium-potassium adenosine triphosphate (ATPase) pump stands guard and maintains the balance.
• Maintenance for an adult is 1mmol/kg/day

Question 15

Hypokalaemia
What are the signs and symptoms?
What drugs can cause Hyperkalaemia?
What is given?

Answer 15

• ECG changes, arrhythmias
• Metabolic changes
• Postural hypotension
• Constipation
• Ileus
• Diuretics
• Laxatives
• Amphotericin, aminoglycosides,
• Insulin e.g. in treatment of diabetic ketoacidosis
• Caffeine, theophylline, adrenaline, salbutamol
• Magnesium depletion
• Oral/ enteral: Sando K, Kay-Cee-L
• IV Peripherally
• IV via central line

Question 16

Hyperkalaemia:
What are the Signs and symptoms?
What drugs can cause hyperkalaemia?

Answer 16

Signs and symptoms:
* ECG changes, bradycardia
* Muscle pain, weakness,
numbness
* Oliguria/ anuria

• ACEi, ARBs
• Potassium-sparing diuretics
• Renal and diabetic
  complications
• Lithium
• Digoxin
• Calcium gluconate → reduce arrhythmias by antagonising cardiac membrane excitability without affecting K+ levels (protect cardiac myocytes)
• Rapid-acting insulin to shift potassium back into cells
• Remove k+ by giving diuretic (cation exchange resin if chronic); kindey filtration,
  correction of metabolic disease
• Prevent recurrence