General

Question 1

Daily requirement of fluid and electrolytes?

Answer 1

NICE guidelines:

• 25-30ml/kg/24 hours water
• 1 mmol/kg/24h of Na+
• 1 mmol/kg/24h of K+
• 1 mmol/kg/24h of Cl-
• 50-100g/24h of glucose

Question 2

What are the types of IV fluids?

Answer 2

CRYSTALLOIDS e.g. 0.9% NaC, Hartmann’s, dextrose
- very widely used, cheaper than colloids

COLLOIDS e.g. gelofusine, human albumin solution (HAS)

• high colloid osmotic pressure so theoretically retains more fluid in the intravascular compartment (not much evidence)
• rarely used
• HAS used routinely for patients with decompensated liver disease and hypoalbuminaemia

Question 3

What are the normal levels of Na, K, Ca, Cl, HCO3, pH, and osmolality?

Answer 3

Na - 135-145
K - 3.5-5.0
Ca - 2.2-2.6
Cl - 100-110 
HCO3 - 22-26
pH - 7.35-7.45
Osmolality - 275-300 mOsm

Question 4

What are the levels of Na, K, Ca, Cl, HCO3, pH, and osmolality in 5% dextrose?

Answer 4

Na - 0 
K - 0
Ca - 0
Cl - 0
HCO3 - 0
pH - 4.1
Osmolality - 278 mOsm

Question 5

What are the levels of Na, K, Ca, Cl, HCO3, pH, and osmolality in 0.9% saline?

Answer 5

Na - 154
K - 0 
Ca - 0 
Cl - 154
HCO3 - 0
pH - 5.5
Osmolality - 300

Question 6

What are the levels of Na, K, Ca, Cl, HCO3, pH, and osmolality in Hartmann’s?

Answer 6

Na - 131
K - 5
Ca - 4
Cl - 112
HCO3 - 29
pH - 6.5
Osmolality - 281

Question 7

How to approach fluid RESUSCITATION

Answer 7

Typically fluid challenge of 250-500ml of Normal saline/Hartmann’s (not dextrose) over 15min-1h

Reassess A-E after each fluid bolus

Question 8

How to approach fluid REPLACEMENT

Answer 8

What are the sources of losses?
- high output stoma? Vomiting? Diarrhoea? Third space losses? diuresis? febrile?

What are the electrolyte/blood imbalances?

• dehydration - high urea:creatinine ration
• vomiting - low K+, low Cl-, alkalosis
• diarrhoea - low K+ and acidosis

Question 9

What 24h maintenance fluids are required for a 70kg male who is currently euvolaemic?

Answer 9

Reminder dialy requirements are:

• 25-30ml/kg/24 hours water
• 1 mmol/kg/24h of Na+
• 1 mmol/kg/24h of K+
• 1 mmol/kg/24h of Cl-
• 50-100g/24h of glucose

So this man needs

• 1750-2100ml of water
• approx 70 mmol K+, Na+ and Cl-
• approx 50-100g glucose

Question 10

Same 70kg year old man. What is an example of the regime they could have?

Answer 10

One salty two sweet

• 500ml 0.9% NaCl + 20mmol KCl over 8 hours (this gives all their Na and Cl requirement and a third of their K, and a quarter of their water)
• 1L of 5% dextrose +20mmol KCl over 8 hours (provides additional half of water, and provides dextrose and another third of their K)
• 500ml of 5% dextrose + 20 mmol KCl over 8 hours ( gives last quarter of water requirement and final third of K, and provides dextrose)

Question 11

45 year old male had laparoscopic appendicectomy 3/7 ago. Bowels not opened since operation, not passing flatus. vomiting started overnight, approx 1L in total. NGT inserted, patient is NBM. CT abdo excludes bowel obstruction and suggests post-op ileus. PMHx HTN. DHx ramipril, NKDA.

A - patent
B - equal AE throughout, normal breath sounds, RR 18, sats 98% RA
C - HR 105, BP 95/55, cool peripheries, CRT 3 sec, no JVP, dry mucous membranes, no pedal/sacral oedema, no catheter/fluid balance
D - GCS 15, PEARL, BM 5.2
E - abdomen distended but soft, absent bowel sounds, temp 36.5, calves SNT, weight 70kg

Answer 11

He needs fluid resus

500ml bolus of NaCl then re-assess