Fluid Therapy & JVP Flashcards
1
Q
dWhat 2 major groups can IV fluids be categorised into?
A
1) Crystalloids
2) Colloids
2
Q
What are crystalloids? Give 3 examples
A
Solutions of small molecules in water
- sodium chloride
- Hartmann’s
- dextrose
3
Q
What are colloids?
Give 2 examples
A
Solutions of larger organic molecules.
- albumin
- Gelofusine
4
Q
Name 4 commonly used fluids
A
1) Sodium chloride 0.9% (normal saline)
2) Hartmann’s solution
3) Sodium chloride 0.18% / glucose 4%
4) 5% dextrose
5
Q
What are isotonic solutions?
A
IV fluids that have a similar concentration of dissolved particles as blood.
6
Q
What are hypertonic solutions?
A
Hypertonic fluids 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.
7
Q
What is a hypotonic solution?
A
A hypotonic fluid is a solution with a lower concentration of electrolytes than body plasma.
8
Q
Give an example of a hypotonic solution
A
0.45% sodium chloride
9
Q
Is normal saline iso/hypo/hypertonic?
A
Isotonic
10
Q
Is Hartmann’s solution iso/hypo/hypertonic?
A
Isotonic
11
Q
Is 5% dextrose iso/hypo/hypertonic?
A
Hypotonic
12
Q
What does 5% dextrose solution contain?
A
Only dextrose and water
13
Q
What is dextrose?
A
The D-isomer of glucose
14
Q
Does 5% dextrose have a role in fluid resuscitation?
A
No - only maintenance.
15
Q
What is the main advantage of 5% dextrose?
A
Being able to maintain hydration without administering an excess of electrolytes, and it can also be prescribed with supplementary potassium if required.
16
Q
Does 5% dextrose have any substantial calorific or nutritional value?
A
No
17
Q
What does normal saline contain?
A
Na+, Cl- and water.
18
Q
Indications for normal saline?
A
Can be used in both resuscitation and maintenance regimes.
Potassium can be added to the solution too, aiding in electrolyte management.
19
Q
Why should normal saline not be used as a lone fluid maintenance?
A
as excessive saline replacement can result in a hyperchloraemic acidosis.
20
Q
What doe Hartmann’s solution contain?
A
Na+, Cl–, K+, HCO3– (as lactate), Ca2 and water.
21
Q
Indications for Hartmann’s solution?
A
Similar to Normal Saline, it distributes in the intra-vascular and interstitial spaces, making it useful for both resuscitation and fluid maintenance.
22
Q
How does Hartmann’s differ from normal saline?
A
1) Hartmann’s solution is considered to be more “physiological” than Normal Saline as it contains other electrolytes in concentrations similar to plasma.
2) It also contains lactate, which it uses to generate alkalising HCO3– ions.
23
Q
Why should there should be a guarded use of lactate as a marker of acidosis if patients have received Hartmann’s solution?
A
As Hartmann’s contains lactate anions –> can interfere with the usefulness of serial lactate measurements.
24
Q
Aim os using colloids?
A
Colloids are solutions containing proteins with large molecular weights, aiming to maintain a high plasma oncotic pressure to keep fluid within the intravascular compartment (in theory an advantage during fluid resuscitation).
However, clinical trials have shown their limited benefit in resuscitation*, and they also come with a small risk of anaphylaxis.
25
Indications for human albumin solution (HAS)?
HAS is still routinely used in patients who are unable to produce sufficient protein (e.g. decompensating liver disease). By temporarily increasing the plasma oncotic pressures, HAS allows intravascular volumes to be maintained.
26
When prescribing IV fluids, what are the 5 Rs that should be remembered?
1) resuscitation
2) routine maintenance
3) replacement
4) redistribution
5) reassessment
27
What are the general key considerations when prescribing fluids?
1) Is the aim of the fluid for resuscitation, maintenance, or replacement?
2) What is the weight and size of the patient?
3) Are there any co-morbidities present that are important to consider, such as heart failure or chronic kidney disease?
4) What is their underlying reason for admission? (After some operations, patients are deliberately run “on the dry side”, whilst septic patients or patients in bowel obstruction will need aggressive fluid prescribing).
5) What were their most recent electrolytes?
28
What are the 3 main reasons for fluid prescription?
1) resuscitation
2) maintenance
3) replacement
29
What is the distribution of fluid intracellularly vs extracellularly?
Around 2/3 distributes in to the intracellular fluid and the remaining 1/3 distributes in to the extracellular fluid.
30
Of that fluid in the extracellular space, what is the distribution between intravascular and interstitium?
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.
31
What does 'fluid resuscitate' mean?
Improving tissue perfusion by raising the intravascular volume.
32
If the aim is to fluid resus a patient, where is it important that fluids stay?
Within the intravascular compartment - this concept will help to understand why different fluids are available and for what purpose they might be used.
33
What are fluid losses from non-urine sources called?
Insensible losses
34
How are insensible losses affected in unwell patients?
Insensible losses will rise in unwell patients, who may be febrile, tachypnoeic, or having increased bowel output.
These factors should be taken into account when deciding how much fluid a patients needs replacing.
35
What clinical signs may you be looking for in a dehydrated patient?
1) Dry mucous membranes and reduced skin turgor
2) Decreasing urine output (should target >0.5 ml/kg/hr)
3) Orthostatic hypotension
4) In worsening stages:
- increased CRT
- tachycardia
- low BP
36
What clinical signs may you be looking for in a fluid overloaded patient?
1) raised JVP
2) peripheral or sacral oedema
3) pulmonary oedema
37
What is the suggested daily requirements for:
a) water
b) Na+
c) K+
d) glucose
per day when prescribing fluids?
a) 25 mL/kg/day
b) 1.0 mmol/kg/day
c) 1.0 mmol/kg/day
4) 50g/day
38
In a 70kg healthy male, you need to precribe fluids over 24h that provide how much:
a) water
b) Na+
c) K+
d) glucose
a) 1750ml (75 x 25 mL/kg/day)
b) 70 mmol
c) 70 mmol
d) 50g/day
39
Give an example of a typical fluid maintenance regimen in a healthy 70kg male
1st bag:
- 500mL of 0.9% saline with 20mmol/L K+ to be run over 8 hours
- This provides all of their Na+, around 1/3rd of their K+, and a quarter of their water
2nd bag:
- 1L of 5% dextrose with 20mmol/L K+ to run over 8 hours
- This provides a further 1/3rd of their K+, and half of their water, as well as glucose
3rd bag:
- 500mL of 5% dextrose with 20mmol/L K+ to run over 8 hours
- This provides the remaining 1/3rd of their K+, and a quarter of their water, as well as glucose
40
What is a reduced urine output defined as?
<0.5ml/kg/hour
41
Management of any reduced urine output (<0.5ml/kg/hr)?
Should be managed aggressively, giving a fluid challenge and the clinical parameters (including urine output) subsequently rechecked (also ensuring any catheter is not blocked or patient not retaining urine).
42
What should a fluid challenge in a patient with reduced urine output consist of?
The fluid challenge should be either 250ml or 500ml over 15-30mins, depending on the patient’s size and co-morbidities.
For example a 120kg 30yr male may need >500 ml to make any difference to their intravascular volume, whereas in a frail 80yr lady with ischaemic heart disease and renal disease, 250ml may be more appropriate.
43
When prescribing fluids you should assess any excess losses.
What 5 things should be look at?
1) Are there any third-space losses?
2) Is there a diuresis (increased or excessive production of urine)?
3) Is the patient tachypnoeic or febrile ?
4) Is the patient passing more stool than usual (or high stoma output)?
5) Are they losing electrolyte-rich fluid?
44
What is a third space loss?
Third-space losses refer to fluid losses into spaces that are not visible, such as the bowel lumen (in bowel obstruction) or the retroperitoneum (as in pancreatitis).
45
Define hypovolaemia
Hypovolaemia refers to an overall deficit of fluid in the body.
46
Give some causes of hypovolaemia
1) poor fluid intake
2) excessive fluid loss e.g. vomiting, diarrhoea, excessive diuretic therapy
3) 3rd space loss of fluid
47
Define hypervolaemia
Hypervolaemia refers to an excess of fluid in the body ('fluid overload')
48
Causes of hypervolaemia?
1) excessive fluid intake
2) inappropriate fluid retention e.g. HF, RF
49
What are some patient factors to consider that may alter fluid homeostasis?
1) age
2) reasons for admission that can increase fluid requirements
3) medical conditions that can affect fluid balance e.g. HF, RF
4) medications e.g. diuretics can increase fluid losses
5) pertinent details in patient history
50
Why may age affect a patient's hydration status?
Elderly/very young patients are more prone to dehydration.
Elderly patients are generally more likely to have cardiac failure and/or chronic renal disease.
51
Which age groups are more prone to dehydration?
elderly/very young patients are more prone to dehydration
52
What are some reasons for admission that can increase fluid requirements?
- trauma
- febrile illness & sepsis
- burns
- surgical patients may need additional volume 2ary to bleeding, drainage, and 3rd space losses
- GI losses e.g. vomiting, diarrhoea
- polyuria
53
What are some pertinent details in the patient’s history that be relevant towards their hydration status?
1) bleeding
2) vomiting: frequency, volume, blood
3) stool: frequency, volume, blood
4) fever and diaphoresis
5) urine output: colour and volume
6) pre-syncope/syncope
7) presence of thirst
8) eating and drinking status (e.g. oral fluids, nil by mouth, receiving IV fluid therapy)
9) symptoms of fluid overload (e.g. shortness of breath, orthopnoea, paroxysmal nocturnal dyspnoea, leg swelling)
10) is the patient on a fluid restriction for another medical condition (e.g. heart failure)?
54
When conducting a hydration assessment of a patient (OSCE), what clinical signs (end of bed) may you be looking for?
- cyanosis
- SOB
- pallor
- malar flush
- oedema
55
What may cyanosis indicate about hydration status?
Hypovolaemia may cause peripheral vasoconstriction, resulting in poor circulation.
56
What may SOB indicate about hydration status?
may indicate pulmonary oedema secondary to fluid overload
57
What may pallor indicate about hydration status?
Can suggest underlying anaemia (e.g. haemorrhage, chronic disease) or poor perfusion (e.g. hypovolaemia).
58
What is malar flush associated with?
Mitral stenosis
59
What objects and equipment may you look for during hydration assessment?
1) medical equipment e.g. O2 delivery device, IV fluid, stoma bag, urinary catheter (colour, volume)
2) mobility aids
3) pillows (HF)
4) vital signs
5) fluid balance chart
6) daily weight chart
7) stool chart: frequency and type
8) medication chart e.g. diuretics
9) fluid prescription chart
10) surgical documentation (if patient is post-op): check the estimated blood loss in the operating theatre and if any blood or fluid was administered intraoperatively.
60
What would you examine the hands for in a hydration assessment?
1) inspection: colour & leukonychia
2) temperature
3) CRT
4) skin turgor
61
What may leukonychia suggest about hydration status?
This is a whitening of the nail bed, associated with hypoalbuminaemia (e.g. end-stage liver disease, protein-losing enteropathy).
Hypoalbuminaemia can result in significant third space fluid loss.
62
What is leukonychia associated with?
Hypoalbuminaemia
63
How to assess skin turgor?
Assess skin turgor by gently pinching a fold of skin (this can be done on the back of the hand), holding for a few seconds and then releasing the skin.
Well hydrated skin should spring back to its previous position immediately, whereas dehydrated skin will slowly return to normal (this is known as decreased skin turgor).
64
How can hypovolaemia affect BP?
1) hypotension
2) postural drop
65
What defines a postural drop?
more than a 20mmHg decrease in systolic blood pressure when moving from sitting to standing
66
How can hypervolaemia affect BP?
HTN
67
Causes of a narrow pulse pressure?
aortic stenosis, congestive heart failure and cardiac tamponade.
68
Causes of a wide pulse pressure?
Causes include aortic regurgitation and aortic dissection.
69
Define a wide pulse pressure
more than 100 mmHg of difference between systolic and diastolic blood pressure
70
Define a narrow pulse pressure
less than 25 mmHg of difference between the systolic and diastolic blood pressure
71
What may more than 20mmHg difference in blood pressure between each arm indicate?
Aortic dissection
72
What does the JVP provide an indirect measure of?
Central venous pressure.
73
How does the JVP provide an indirect measure of central venous pressure?
This is possible because the internal jugular vein (IJV) connects to the right atrium without any intervening valves, resulting in a continuous column of blood.
The presence of this continuous column of blood means that changes in right atrial pressure are reflected in the IJV (e.g. raised right atrial pressure results in distension of the IJV).
74
How can the IJV be differentiated from the external carotid artery?
The IJV has a double waveform pulsation
75
How to measure the JVP?
By assessing the vertical distance between the sternal angle and the top of the pulsation point of the IJV
76
What should the JVP be?
<3cm
77
What does a raised JVP indicate?
venous hypertension/hypervolaemia
78
Give 3 cardiac causes of a raised JVP
1) Right-sided heart failure
2) Tricuspid regurgitation
3) Constrictive pericarditis
79
Give 2 causes of right HF
1) left-sided heart failure.
2) pulmonary hypertension: often occurring due to COPD or interstitial lung disease.
80
What are 2 causes of tricuspid regurgitation?
1) infective endocarditis
2) RHD
81
Causes of constrictive pericarditis?
Often idiopathic, but rheumatoid arthritis and tuberculosis are also possible underlying causes.
82
What are you examining the face for in hydration assessment?
1) Eyes:
- sunken appearance
- conjunctival pallor
2) Mouth:
- dry mucous membranes
83
What are you examining chest for in hydration assessment?
1) RR
2) Central CRT
3) Auscultate heart sounds
4) Auscultate & percuss the lungs
84
What may a raised RR indicate a
may indicate pulmonary oedema secondary to hypervolaemia.
85
When is a central CRT indicated?
If capillary refill time was prolonged on peripheral assessment, repeat again over the sternum.
86
What is a gallop rhythm?
a third heart sound occurring after the normal ‘lub’ ‘dub’ heart sound.
87
What may a gallop rhythm indicate about fluid st
May be noted in hypervolaemia due to elevated atrial and ventricular filling pressures.
A gallop rhythm is typically associated with heart failure although it can also be present in healthy athletic individuals.
88
Who is a gallop rhythm typically seen in?
1) HF
2) healthy athletic individuals.
89
What are you assessing abdomen for in hydration assessment?
1) distension
2) striae
3) shifting dullness
90
What type of fluid is 0.45% sodium chloride?
Hypotonic
91
Why should hypotonic (0.45% sodium chloride) fluids be avoided in paediatric patients?
They are at higher risk of risk of hyponatraemic encephalopathy.
92
What is the JVP an indirect measure of?
Pressure in the RA (and venous system).
I.e. higher pressure in RA = raised JVP
93
Causes of higher pressure in RA i.e. venous HTN (and therefore raised JVP)?
1) Right HF: caused by left HF and pulmonary HTN (due to COPD or interstitial lung disease)
2) Fluid overload
3) Constrictive pericarditis
4) Cardiac tamponade
5) Tricuspid regurgitation: caused by infective endocarditis, RHD
94
How is the JVP assessed?
By looking at the right internal jugular vein.
95
What does the internal jugular vein run underneath?
Sternocleidomastoid muscle
96
What structure is found lateral to the internal jugular vein?
External jugular vein (don't use for the JVP!)
97
Why is the right IJV used for assessment of the JVP?
As this sits most directly above the RA (gives us best indication).
98
How is the JVP visualised?
1) Patient sits on back at 45 degree angle
2) Turn head to left
3) JVP visualised between the medial clavicle and the earlobe
4) JVP pulsation is like a wave (2 pulses for each contraction of the heart)
99
What 2 ways can the JVP be distinguised from the carotid pulse?
1) JVP has 2 pulses for each heartbeat
2) Carotid pulse has a pulsation you can palpate, but JVP does not (i.e. won't be able to feel anything with your fingers)
100
How does pressing on the liver affect JVP?
Will cause temporary rise in JVP (hepatojugular reflex)
101
How is the height of the JVP measured?
1) Find angle of sternum
2) Measure vertically fro this point
3) Assess where the JVP is --> vertical height from the sternal angle to the level of the JVP (this is the JVP height)
102
Normal height of JVP?
<3cm
103
What does the IJV drain into?
SVC
104
What are the different parts of the JVP waveform?
A wave
X descent (part 1)
C wave
X descent (part 2)
V wave
Y descent
105
What is the A wave of the JVP waveform caused by?
Contraction of the RA, where blood is being pumped through the tricuspid valve into the RV.
Increased pressure in the right atrium also forces blood upwards towards and into the IJV.
This influx of venous blood into the IJV is known as the A wave.
106
What is the first part of the X descent of the JVP waveform caused by?
Relaxation of the RA --> results in blood filling the RA from the SVC, reducing the height of the column of blood sitting in the IJV (i.e. causing a drop in the JVP).
The RV relaxing also contributes to the X descent, as blood exits the right atrium into the right ventricle, further reducing the column of blood in the SVC and IJV.
107
What is the C wave of the JVP waveform caused by?
Forceful contraction of the RV which ejects blood out of the heart into the pulmonary artery.
As this occurs, the pressure within the RV increases significantly, forcing the tricuspid valve upwards so much so that it projects partially into the RA.
This sudden projection of the tricuspid valve into the RA generates upwards force which is transmitted into the SVC and ultimately the IJV, causing a temporary rise in the JVP --> C wave.
108
What causes the 2nd part of the X descent?
This occurs during the final phase of RV contraction.
When the ventricle reaches its most contracted state, it is physically much smaller than when in its relaxed state, resulting in the creation of extra space within the pericardium.
This extra space within the pericardium allows the RA to expand and begin filling with blood.
This initial phase of atrial filling results in a drop in venous pressure within the SVC and IVC --> producing the second part of the X descent.
109
What causes the V wave of the JVP waveform?
Relaxation of the RA whilst the tricuspid valve is still closed.
The relaxation of the RA combined with a closed tricuspid valve results in blood being drawn into the column of blood that begins at the RA and extends up to the IJV.
As blood is drawn into the column, whilst the tricuspid valve is closed, the level of the JVP is temporarily increased.
110
What causes the Y descent of the JVP waveform?
The Y descent occurs when the tricuspid valve opens, resulting in blood from the right atrium filling the right ventricle and blood from the SVC and IJV filling the right atrium.
This results in a decrease in the height of the column of blood and thus a decrease in the JVP.
111
