IV Fluids

Question 1

2 categories of fluid space

Answer 1

• Intracellular space 2/3
• Extracellular space 1/3
  
  • Intravascular space 20%
  • Interstitial space 80%
  • Third space

Question 2

What is third space

Answer 2

• Areas of body that do not normally contain fluid
  
  • Peritoneal cavity (forming ascites)
  • Pleural cavity (forming pleural effusions)
  • Pericardial cavity (forming percardial effusion)
  • Joints (forming joint effusions)
• Also refers to oedema - excessive collection of fluid in interstitial space

Question 3

Complications of third spacing

Answer 3

Fluid shifting into non-functional third space can come at expense of the intravascular space, causing hypotension and reduced perfusion of tissues

Question 4

How is fluid balance recorded

Answer 4

All fluid intake and output can be recorded on fluid balance chart

Question 5

Sources of fluid intake

Answer 5

• Oral fluids
• Nasogastric or PEG feeds
• Intravenous fluids (including IV medications)
• Total parenteral nutrition

Question 6

Sources fluid output

Answer 6

• Urine output
• Bowel or stoma output (particularly diarrhoea)
• Vomit or stomach aspiration
• Drain output
• Bleeding
• Sweating

Question 7

What are insensible fluid loss

Answer 7

Refers to fluid output that is difficult to measure such as through respiration, stools, burns and from sweat

Question 8

Signs of hypovolaemia

Answer 8

• Hypotension (systolic < 100 mmHg)
• Tachycardia (heart rate > 90)
• Capillary refill time > 2 seconds
• Cold peripheries
• Raised respiratory rate
• Dry mucous membranes
• Reduced skin turgor
• Reduced urine output
• Sunken eyes
• Reduced body weight from baseline
• Feeling thirsty

Question 9

Signs of hypervolaemia

Answer 9

• Peripheral oedema (check the ankles and sacral area)
• Pulmonary oedema (shortness of breath, reduced oxygen saturation, raised respiratory rate and bibasal crackles)
• Raised JVP
• Increased body weight from baseline (regular weights are an important way of monitoring fluid balance)

Question 10

Do patients with third spacing present with signs of hypo or hypervolaemia

Answer 10

Both as may have low levels in intravascular space but excessive fluid in other areas such as interstitial space or peritoneal cavity

Question 11

Main indications for IV fluids

Answer 11

• Resuscitation (e.g., sepsis or hypotension)
• Replacement (e.g., vomiting and diarrhoea)
• Maintenance (e.g., nil by mouth due to bowel obstruction)

Question 12

2 main groups IV fluid

Answer 12

• Crystalloids
• Colloids

Question 13

What are crystalloids

Answer 13

Water with added salts or glucose, contents redistritbutes through different fluid compartments of body

Question 14

Examples of crystalloids

Answer 14

• 0.9% sodium chloride (“normal saline”)
• 5% dextrose
• 0.18% sodium chloride in 4% glucose
• Hartmann’s solution
• Plasma-Lyte 148

Question 15

What does 1L bag of 0.9% saline solution contain

Answer 15

• 1 litre of water
• 154 mmol sodium (note that this is a lot of sodium, and lots of saline can result in hypernatraemia)
• 154 mmol chloride

Question 16

What does 1L bag 5% dextrose contain

Answer 16

• 1 litre of water
• No electrolytes (note that lots of hypotonic fluid can result in hyponatraemia and oedema)
• 50 g of glucose

Question 17

What does 1L bag 0.18% sodium chloride contain in 4% dextrose

Answer 17

• 1 litre of water
• 31 mmol sodium
• 31 mmol chloride
• 40 g of glucose

Question 18

What does 1L bag hartmann solution contain

Answer 18

• 1 litre of water
• 131 mmol sodium
• 111 mmol chloride
• 5 mmol potassium
• 2 mmol calcium
• 29 mmol lactate (helps to buffer the solution – reducing the risk of acidosis)

Question 19

What does 1L bag of plasma-lyte 148 contain

Answer 19

• 1 litre of water
• 140 mmol sodium
• 98 mmol chloride
• 5 mmol potassium
• 1.5 mmol magnesium
• 27 mmol acetate (helps to buffer the solution – reducing the risk of acidosis)
• 23 mmol gluconate (helps to buffer the solution – reducing the risk of acidosis)

Question 20

What are colloids

Answer 20

Contain larger molecules that stay in intravascular space

Question 21

1 example colloid

Answer 21

Human albumin solution

Question 22

What is tonicity

Answer 22

Refers to osmotic pressure gradient between two fluids across a membrane, which determines whether water molecules will move accross membrane by osmosis

Water moves from area of lower concentration to area of higher concentration

Question 23

Normal serum osmolarity

Answer 23

275-295mOsmol/kg

Question 24

3 types of tonicity solutions can be

Answer 24

• Isotonic solutions
• Hypotonic solutions
• Hypertonic solutions

Question 25

Examples of isotonic solutions

Answer 25

• 0.9% saline
• Hartmanns
• Plasma-lyte

Question 26

Examples of hypotonic solutions

Answer 26

• 5% dextrose
• 0.18% sodium choride

Question 27

Examples of hypertonic solutions

Answer 27

3% saline

Question 28

What fluid should be used for fluid resuscitation

Answer 28

• Isotonic fluid
  
  • 0.9% saline
  • Hartmann’s solution
  • Plasma-Lyte 148

Question 29

What should never be given as rapid infusions

Answer 29

Potassium - can induce arrhythmia or cardiac arrest

Infusion should not exceed 10mmol/hour

Question 30

Approximate requirements for maintanence fluids

Answer 30

• 25-30ml/kg/day water
• 1mmol/kg/day of sodium, potassium and chloride
• 50-100g/day glucose (to prevent ketosis, not to meet nutritional needs)

Question 31

NICE guideline for fluid maintenence

Answer 31

• Start with 25-30ml/kg/day of 0.18% sodium chloride in 4% glucose with 27mmol/L of added potassium

Question 32

NICE guidelines for fluid resuscitation

Answer 32

• An initial 500ml fluid bolus over 15 minutes (“stat”) followed by reassessment with ABCDE
• Repeat boluses of 250-500ml of fluid if required, each time with reassessment
• Seek expert help if patient not responding, particularly after 2L fluid

Question 33

What does daily monitoring when using fluid maintenance involve

Answer 33

• Assessment of fluid status
• Fluid balance chart
• U&E blood test

Question 34

Maximum time of fluid allowed to prescribe

Answer 34

24 hours

Question 35

Too much fluid can lead to dilution of

Answer 35

• Sodium (with hypotonic solutions)
• Potassium (if potassium is not included)
• Other electrolytes, e.g., calcium or magnesium
• Haemoglobin and haematocrit (red blood cells in the blood) causing anaemia
• Clotting factors, platelets and fibrinogen causing coagulopathy (clotting problems)

Question 36

With what conditions should seniours guide

Answer 36

• Elderly or frail patients
• Significant oedema
• Sodium imbalance (hyponatraemia or hypernatraemia)
• Heart failure
• Renal impairment
• Liver impairment