Revision - Fluid Therapy

Question 1

What is an isotonic solution?

Answer 1

IV fluids that have similar concentration of dissolved particles as blood.

E.g. 0.9% saline

Question 2

What is a hypertonic solution?

Answer 2

Contain a higher concentration of solute compared to plasma and interstitial fluid; this creates an osmotic gradient and drives fluid FROM the interstitial space INTO the intravascular space.

E.g. 3% saline, mannitol

Question 3

What is a hypotonic solution?

Answer 3

A solution with a lower concentration of electrolytes than body plasma.

E.g. 0.45% saline

Question 4

Movement of fluid when giving a hypertonic solution?

Answer 4

Movement of fluid from interstitial space into the intravascular space.

Question 5

Movement of fluid when giving a hypotonic solution?

Answer 5

Movement of fluid from intravascular space into the interstitial space.

Question 6

Is 5% dextrose iso/hypo/hypertonic?

Answer 6

Hypotonic

Question 7

Why should normal saline not be used as a lone fluid maintenance?

Answer 7

Can result in hyperchloraemic acidosis

Question 8

What is the distribution of fluid intracellularly vs extracellularly?

Answer 8

Around 2/3 distributes in to the intracellular fluid and the remaining 1/3 distributes in to the extracellular fluid.

Question 9

Of that fluid in the extracellular space, what is the distribution between intravascular and interstitium?

Answer 9

Of that fluid in the extracellular space, around 1/5th stays in the intravascular space and 4/5th of this is found in the interstitium, with a small proportion in the transcellular space.

Question 10

If the aim is to fluid resus a patient, where is it important that fluids stay?

Answer 10

Within the intravascular space

Question 11

What may leukonychia suggest about hydration status?

Answer 11

This is whitening of the nail bad associated with hypoalbuminaemia –> can result in significant third space fluid loss.

Question 12

Causes of a narrow pulse pressure?

Answer 12

1) aortic stenosis
2) cardiac tamponade
3) cardiac failure

Question 13

Causes of a wide pulse pressure?

Answer 13

1) aortic regurg
2) aortic dissection
3) Cushing’s reflex

Question 14

Define a wide pulse pressure

Answer 14

more than 100 mmHg of difference between systolic and diastolic blood pressure

Question 15

Define a narrow pulse pressure

Answer 15

less than 25 mmHg of difference between the systolic and diastolic blood pressure

Question 16

What may more than 20mmHg difference in blood pressure between each arm indicate?

Answer 16

Aortic dissection

Question 17

What does the JVP provide an indirect measure of?

Answer 17

Central venous pressure

Question 18

What should the JVP be?

Answer 18

<3cm

Question 19

Why should hypotonic (0.45% sodium chloride) fluids be avoided in paediatric patients?

Answer 19

They are at higher risk of risk of hyponatraemic encephalopathy.

Question 20

What is the JVP an indirect measure of?

Answer 20

Pressure in the RA (and venous system).

I.e. higher pressure in RA = raised JVP

Question 21

Is the internal or external jugular vein used for JVP assessment?

Answer 21

Internal

Question 22

Why is the right IJV used for assessment of the JVP?

Answer 22

As this sits most directly above the RA (gives us best indication).

Question 23

What does the IJV drain into?

Answer 23

SVC

Question 24

Size of NPA for an average size male?

Answer 24

7mm

Question 25

Size of NPA for an average size female?

Answer 25

6mm

Question 26

What can be given to aid intubation in RSI?

Answer 26

The administration of the induction agent (e.g. Propofol or Sodium Thiopentone) and paralysing agent (e.g. Suxamethonium or Rocuronium).

Question 27

What airway management can be used to facilitate long term weaning?

Answer 27

Tracheostomy

Question 28

What 3 veins may a central line be inserted into?

Answer 28

1) Subclavian vein

2) Internal jugular vein

3) Femoral vein

Question 29

What is a peripherally inserted central catheter (PICC line)?

Answer 29

A type of central venous catheter

A long, thin tube is inserted into a peripheral vein (e.g., in the arm) and fed through the venous system until the tip is in a central vein (the vena cava or right atrium).

Question 30

What is positive airway pressure?

Answer 30

Refers to the pressure OUTSIDE the lungers being GREATER than the pressure inside the lungs.

This results in air being forced INTO the lungs (down the pressure gradient), requiring less respiratory effort.

Question 31

What are 3 key indications for NIV?

Answer 31

1) COPD with respiratory acidosis (pH <7.35)

2) Hypercapnic respiratory failure secondary to chest wall deformity (scoliosis, thoracoplasty) or neuromuscular disease

3) Weaning from tracheal intubation

Question 32

What are 4 key indications for CPAP?

Answer 32

1) Hypoxia in the context of chest wall trauma despite adequate anaesthesia and high flow oxygen (pneumothorax should be ruled out using a chest x-ray prior to commencing CPAP)

2) Cardiogenic pulmonary oedema

3) Pneumonia: as an interim measure before invasive ventilation or as a ceiling of treatment

4) Obstructive sleep apnoea.

Question 33

What are the 4 basic settings on a mechanical ventilator that help maintain adequate gas exchange?

Answer 33

Aid CO2 removal:
- RR
- Tidal volume (volume of gas provided to patient everytime they breathe in)

O2 delivery:
- FiO2
- PEEP

Question 34

How is PEEP helpful in O2 delivery?

Answer 34

PEEP helps to maintain alveolar recruitment, preventing the alveoli from collapsing at the end of expiration (keeping lungs open).

Question 35

What are the 2 main ways that a ventilator can provide a tidal volume to a patient?

Answer 35

1) Pressure control –> the ventilator provides a flow of gases to the lung until a set pressure is reached in the lungs

2) Volume control –> the ventilator provides a flow of gases to the lung until a set volume is reached

Question 36

What is the typical combination of drugs used for intubating a patient/putting them on a ventilator?

Answer 36

Propofol + short-acting opioid (e.g. alfentanil)

Question 37

Adverse effects of mechanical ventilation?

Answer 37

1) Volutrauma (lungs expanded too much –> can cause pneumothorax, inflammation etc)

2) Barotrauma (lungs exposed to too high pressure –> can cause pneumothorax etc)

3) Ventilator assisted pneumonia (VAP)

4) Vocal cord trauma

5) Tracheal stenosis

6) Haemodynamic instability

7) Delirium