Fluid Therapy and Nutrition in Critical Care Flashcards
(126 cards)
1
Q
What percentage weight of the body is water in adults, neonates and paediatric patients?
A
Adult - 60%
Neonate - 80%
Paediatric - 75%
2
Q
What is the 60% water in adults made up of?
A
40% weight is intracellular fluid , and 20% is extracellular fluid
3
Q
What is extracellular fluid
A
Plasma in the blood (intravascular volume)
and fluid that bathes the cells in the rest of the body (interstitial fluid)
4
Q
What is transcellular fluid?
A
CSF and synovial fluid
5
Q
What kind of fluid loss does diarrhoea tend to cause?
A
Extracellular fluid loss
6
Q
What is meant by the tonicity of a solution?
A
The concentration of solutes in it e.g. sodium, electrolytes
7
Q
What is a hypotonic solution?
A
A solution which has a lower concentration of sodium than the plasma
8
Q
What is a hypertonic solution?
A
A solution which has a higher sodium concentration that the plasma
9
Q
What is an isotonic solution?
A
Sodium concentrtion similar to the plasma e.g. Hartmanns
10
Q
What effect does sodium concentrations of solutions have on water?
A
The water will cross the semi-permeable membrane to try and even out the concentrations. The electrolytes/solutes cannot pass this membrane.
11
Q
What is hypotonic dehydration?
A
When too little solute in the body.
12
Q
What is hypertonic dehydration?
A
Losing too much water whilst keeping too much sodium in the fluid outside your cells.
13
Q
What is isotonic dehydration?
A
When you lose equal amounts of solutes and water
14
Q
How can fluids be administered intra-osseously?
A
Via a cannula into the medullary cavity of a long lone e.g. femur.
15
Q
How long does SC fluid take to fully absorb?
A
6-8 hours
16
Q
What type of fluids cannot be administered sc?
A
Those containing glucose
17
Q
What are crystalloids?
A
Solution of cystalline solids that are dissolved in water e.g. sodium or dextrose based.
18
Q
What fluids are good for correcting extracellular fluid losses?
A
Fluids with concentrations of sodium similar to the ECF sodium concentration stay in the ECF compartment
19
Q
How much fluid is required to replace blood loss? Why?
A
Approx 3 times the amount lost. Because only 1/4-1/3rd of the replaced volume remains in the intravascular space after 1-2 hours - the rest is redistributed to the interstitial spaces.
20
Q
Define maintenance requirement of fluids
A
The amount of water and electrolytes required to replace those lost through normal physiological processes i.e. respiration, perspiration, excretion.
21
Q
What is the maintenance fluid calculation for cats and also dogs?
A
Cats:
80 x BW^0.75 over 24 hrs
(2-3mls/kg/hr)
Dogs:
132 x BW^0.75 over 24hrs
(2-6mls/kg/hr)
22
Q
What is the make up of maintenance fluid solutions compared to ECF?
A
Lower sodium and chloride concentrations and higher potassium
23
Q
Why cant hypotonic solutions be used for maintenance?
A
They can cause red blood cells to lyse if given too fast.
24
Q
What is the level of potassium in supplemented fluid that is a minimum and then needs supplemented?
A
20mmol/L
25
What is the maximum rate for potassium infusion?
0.5mEq/kg/hr
26
How does hypertonic saline work? What must be done after?
Given during shock as increases the BP by:
- drawing water from the interstitial space.
Effects of this are transient (last 30-120min). The use of hypertonic saline must be followed by administration of isotonic crystalloids to replace borrowed water and provide a long term increase in circulating volume.
27
What is the suggested dose of hypertonic saline?
4mls/kg over 10 minutes
28
How do colloids work?
They are fluids which contain large molecules that cannot pass out of the vasculature, they increase the colloid osmotic pressure of the plasma. In addition to the fluid they add, they also 'pull' water from the interstitial space into the intravascular space.
29
What must be done after colloid administration and why?
Administer crystalloids concurrently or just after to pay back the fluid drawn from the interstitial spaceto avoid dehydrating the interstitium.
30
What is the general rule for the dose of colloids that can be given?
Why?
No more than 25% (usually 20mls/kg) of the circulating volume of an animal should be administered as a colloid at any one time.
Otherwise the haemodilution will dilute out clotting factors.
31
Name some artificial and natural colloids?
Artificial - starches, gelofusin, dextrans
Natural - plasma, albumin preparations, whole blood
32
What are the disadvantages of colloids?
- volume overload
- anaphylactic reactions
- clotting problems
33
How long do the various plasma volume expanders work?
Gelatin based (gelofusin) lasts for max 6-8hrs
Dextran based lasts approx 12 hrs
Starch based 24-36hrs
34
How can we visually assess dehydration?
- moistness of mm
- skin turgor (tent)
- sunkness of eyes
35
How can we diagnostically assess dehydration?
- PCV
- TP
-UREA
-USG
NA+
36
What are the clinical signs of less than 5% dehydration?
NOne
37
What are the clinical signs of 5% dehydration?
- semi-dry mm
- skin turgor normal
- eyes moist
38
What are the clinical signs of 6-7% dehydration?
- dry mm
- eyes moist
- mild loss of skin turgor
39
What are the clinical signs of 8-10% dehydration?
Dry mm
Eyes retracted
Considerable loss of skin turgor
signs of hypoperfusion
40
What are the clinical signs of 10% dehydration?
Very dry mm
Severe eyeball retraction
Eyes dull
Complete loss of skin turgor
Altered consciousness
Greater signs of hypoperfusion
41
What are the clinical signs of 12% and 12-15% dehydration?
Same as 10%, but 12 moribund and 15 dying
42
What is the difference between dehydration and hypoperfusion?
Dehydration is when water is lost from all fluid compartments and hypoperfusion is due to inadequate circulating volume. Often seen alongside each other but not the same thing.
43
How do we calculate the fluid deficit in an animal?
Pecentage dehydration (as clinically observed) x BW
44
What is the density of water?
1g/ml
45
If you dont want to weight vomit or diarrhoea, what value can we assume needs to be replaced after each episode in a dog?
50ml per vomit and 100ml per diarrhoea
46
What fluids would you select for a dehydrated patient and why?
Crystalloids as they will cause water to distribute freelly across all compartments to restore fluid deficits
47
If you wanted to replace a fluid deficit in a dehydrated patient quickly , what fluid woudl you choose and why?
An extracellular volume replacer such as Hartmanns. Because it has a similar sodium concentration to plasma than a maintenance crystalloid and is therefore safer to infuse at a faster rate
48
How do we calculate the number of drops per minute if we know the fluid therapy rate (FTR) and the drops per ml (DPMl) of the giving set ?
First calculate the drops per hour so FTR X DPMl = drops per hour.
Divide drops per hour by 60 to get drops per minute.
49
What is the AAHA recommendations for fluid therapy under GA?
Dogs 5mls/kg/hr
Cats 3mls/kg/hr
every hour reduce by 25% until maintenance reached
50
What are the values of systolic, mean and diastolic BP if hypotension present?
Systolic <80-90mmHg
Mean <60-70mmHg
Diastolic <40mmHg
51
How many grams is a 1ml of blood?
1g
52
What are the calculations for blood volume in dog and cat?
Dog 90mls/kg
Cat 56mls/kg
53
How does blood lost volume guide what fluids to pick?
10-15% lost, crystalloid therapy
15-20% colloid therapy
>20% blood products as oxygen carrying capacity affected.
54
In relation to volume of blood lost, how much crystalloid will be needed to replace this and why?
Three times the amount lost as it doesnt indefinitely remain in the intravascular space.
Blood and colloids will remain in the vessels so same amount for them as lost.
55
How much whole blood with a PCV of 40% would be needed to raise the patients PCV by 1%?
2.2mls/kg of the donor blood
56
How much packed red cells with a PCV of 60-80% would be needed to raise the patients PCV by 1%?
1ml/kg
57
What is the more accurate equation for calculating the volume required aof any blood donation?
mls of donor blood required = recipients blood volume x ((desired PCV- current PCV)/Donor PCV)
58
How much blood is one unit in dogs and in cats?
Dogs 450mls and cats 45mls
59
When would we want to use blood products?
When patient has severe acute haemorrhagic shock or various anaemias
60
How whole blood should be stored?
Can be stored for 3w between 1-4degreesC if closed system used to collect.
The blood bag should be agitated every 2-3 days to mic contents.
61
Can whole blood still be used if it goes out of tolerated storage temp of 1-10 degrees?
Yes as long as this was only the case for less than 5 hours and only happened once.
62
How are Packed red cells created?
Separate whole blood into PRCs and plasma. Wash red cells with saline and re-suspend them in minimal saline and SAG-M nutrient solution.
63
What is the volume of a typical canine unit of packed red cells and how are they stored?
200-250mls and stored in fridge between 2-6 degrees and used within 42 days.
64
What is neonatal isoerythrolysis
Har=emolytic anaemia of newborn occurs when mother has antibodies against the blood type of the puppy.
65
How quickly does separated plasma need to be administered after seperation?
Within 6 hours of harvesting as is very rich in clotting factors and platelets. Usually it is frozen to create fresh frozen plasma.
66
How is fresh frozen plasma made?
Plasma harvested from centrifuged blood is frozen to -18 degrees C within 6 hours.
67
FFP can be stored for a year but once thawed how quicly should it be given?
Within 6 hours.
68
Can FFP be re-frozen once thawed?
If above 4C for 24hours or above 22C for 4 hours can be refrozen but labelled as frozen plasma.
69
How much FFP is in a canine unit?
200mls
70
What can FFP be treatment for?
Coagulopathies
Failure of immunity (contains immunoglobulins)
Von Willebrands disease
Pancreatitis
Liver disease with coagulopathy or anaemia
71
When does FFP become FP?
If thawed and re-frozen or if stored for over a year (up to 5 years)
72
How much of FFP with be cryo-precipitate?
60mls out of a 200ml unit
73
What is cryoprecipitate good for? Why?
Von Willebrands. It is a concentrated product containing clotting factor fibrinogen , factor VIII, and von willebrands factor.
74
What is cryoprecipate?
Its a fraction of the plasma that can be separated after patrially thawed FFP is centrifuged.
75
What is cryo-supernatant?
It is the remaining part of partially thawed FFP centrifuged plasma once the cryo-precipitate has been removed.
76
What does cyro-supernatant contain?
Plamsa proteins including albumin, Vit K dependant clotting factors.
77
Out of a 200ml unit of FFP what amount will be cryo-supernatant?
140mls
78
What si cryo-supernatant the treatment of choice for?
haemophilia B
factor IX
Vit K dependant clotting factors
Immunoglobulin transfer
79
What are the positive attributes when selecting a canine blood donor?
Friendly
Clinically well
Aged between 1-8
Large breed dogs (at least 25kg of lean weight)
Fully vaccinated
Easily accessible veins
Universal blood type
80
How are blood types defined in dogs?
Defined by inherited antigens ont eh surface of RBCs (or Dog Erythrocyte Antigens DEAs).
Risk is lowered when recipient does not have antibodies to the donors antigen
81
What DEAs will a universaly donor be negative for?
1 and 7
82
Why is the first transfusion usually safe in a canine patient regardless of blood type?
Dogs rarely possess naturally ocurring alloantibodies so they may develop antibodies if they receive a transfusion but these wont be a problem until they are given it again. They must be cross-matched for subsequent transfusions
83
What is the difference between a major and minor cross-match when blood testing?
Major: assesses the compatibility of the RBCs of the donor and the recipients plasma/serum
Minor: Assesses the compatilibilty of the donors plasma/serum with the recipients RBCs
84
Describe how you wouold perform an emergency cross-match?
On a slide, mix 2 drops of recipient serum with one drop of donors RBCs
- micrscopically examine for agglutination after 5 minutes.
As a control, perform a saline aglutination test for both patient and donor
85
Briefly describe how you would perform a cross-match in house?
Take 1ml of plain and 1ml EDTA for both donor and recipient. Spin down, discard the plasma from the EDTA, and separate the serums from the plain tubes. Add 2-3mls 0.9% NaCl to RBS and invert gently. Re-spin and remove supernatatnt. Repeat a few times. Once supernatant removed again, re-suspend the RBCs in saline (4.8mls saline to 0.2mls RBCs = 4% suspension).
Need 4 tubes. Add blood:
1. Major Cross : 1 drop reciient serum + 1 drop donor RBC suspension
2. Minor cross: 1 drop donor serum + 1 drop recipient RBC suspension
3. Recipient control: 1 drop of each recipient serum and RBC
4. Donor control: 1 drop of each donor RBC and serum
Incubate all tubes at 37C for 15m, prior to centrifuging all tubes at 3400rpm for 15 seconds.
Invert tubes - with compatible samples should be no aglutination/clumping and supernatant should not be haemolysed colour.
Can also examine for agglutination micrsocpically
86
What equipment do you require for canine blood donor collection
PPE
Sterile gloves
Fenestrated drape
Clip and surgical skin prep
Blood collection bag with citrate phosphate dextrose adenosine (CPDA)
Electronic weighing scales
Plastic or guarded haemostat
Tube stripper
87
Briefly describe the procedure of canine donor blood collection
Lat recumbency, clip and prep square over jugular. apply drape. Sampler puts on sterile gloves. Assistant opens collection bag and places on scales and zero'd, positioned lower than the dog. Clamp the line 5cm away from needle.
Sampler inserts needle, clamp undone as blood flows to the collection bag. Once blood enters bag gently rock bag to mix with anti-coagulant.
Stop sampling once bag full and clamp off line. If tube stripper available strip the blood in the line into the bag. Tie the tubing off 5 cm from the bag and cut the excess line off.
Assess donor vitals.
88
What rate and how quickly should the blood collection happen?
40-50mls/minute
A collection of a unit of blood should happen in less than 15 mins.
89
What are the characteristics of a good cat donor?
Friendly
Clinically well
Between 1-8 years old
Large cat - ideally 5kg lean weight
High donor PCV >30%
Ideally indoor cat
Tested for FeLV and FIV.
90
Whar are the 3 main blood grousp in the UK
Group A - Dominant to AB - most common
Group B - Common in some breeds e.g. persian
British shorthair group AB - Recessive to A; co-dominant to B
91
Why is there no universal donor in cats and why cant they have any first transfusion like dogs?
They are born with naturally-occuring allo-antibodies to other cats blood groups
92
Cats will have a reaction if donor doesnt have same blood group, which reactions are fatal?
If recipient B receives A or AB.
93
What is the equipment difference in cat donor collection from dogs.
Similar but use syringe, butterfly and 3 way tap and need to draw up anti-coagulant and insert in syringe and butterfly before collection.
94
What is the ratio of anti-coagulant to whole blood needed for cat blood collection?
1ml anti-coagulant to 7 mls of blood.
95
What rate should cat blood be collected?
5mls/min or greater
96
What are teh advantages of heating red cell products?
Decreases viscocity of product
Reduces chance of hypothermia in patient
cold temps can cause potassium to exit rbcs into the plasma creating high serum potassium
97
What equipment is needed for the administration of blood to the patient?
The blood product
Giving set with in-line filter (to catch any debris or micro-clots) or filter between syringe and IV if small volumes.
98
Why cant we mix hartmanns and blood products?
Citrate (part of the anti-clot in the collection bag) binds to calcium in the blood and stops blood clotting (Calcium is required for the coagulation cascade)
If we add extra calcium in the form of Hartmanns, it allows blood clots.
99
How should we monitor a transfusiion patient?
TPR prior to start of transfusion and continuous monitoring for first 15 minutes.
100
What is the initial transfusion rate? And the following rate?
0.5mls/kg/hr for first 15mins. If no reactions, can increase to 5-20mls/kg/hr.
101
Ideally how long should a blood transfusion take in total?
No more than 4 hours
102
What can we administer directly after a transfusion to ensure lines are emtpy?
Saline
103
How can we monitor if the transfusion was a success in anaemic patients?
Take a post-transfusion blood sample. And another 12 hours later
104
Tranfusion reactions can be immune-mediated or non-immune mediated. Give some clinical signs of each
Immune-mediated:
- Agitation/restlessness
- nausea/vomitting
- urticaria (hives)
- anaphylaxis
- pyrexia
- tachypnoea/dyspnoea
- tachycardia
- hypotension
- seizures
Non-immune:
- hypocalceamia (could be due to too much citrate binding blood)
- circulatory overload
- hypothermia
- infectious disease transmitted
-
105
Why is a central venous cathether (e.g. jugular catheter) beneficial?
Large vessel so large catheter can be used to administer fluids quickly
Drugs administered rach heart super quick
Used for parenteral nutrition or hypertonic fluids as peripherally may cause thrombophlebitis
Good for repeated blood samples.
106
What patients is a jugular catheter contraindicated?
Raised ICP or IOP
Those with coagulaopathies
Those that are immunocompromised
107
Describe the advantages of Seldinger technique to place a jugular catheter
Over a guidewire (J wire) - soft catheters can be used.
- allows entry to vein with minimal trauma to surrounding tissues.
- easier technique
108
What equipment is required to place a jugular catheter?
- a jugular catheter kit
- hep saline
- suture material
- sterile swabs
- prep
- sterile gloves
- drape
- dressing materials
109
Describe the process of placing a jugular catheter using the Seldinger technique
- collect materials
- GA/sedate patient. Monitor
- Clip, prep and drape area over jugular
- position patient in R lat and stand against their back
- Raise vein (unsterile underneath) nic down with blade, and insert needle or introducer catheter towards heart
Withdraw J wire into the coil and then thread off into jugular through the in place introducer catheter. Remove introducer. Then thread dilator twisted down to make the hole bigger and then removing (leaving guide wire). Thread catheter over guide wire until hub at skin, then remove guid wire. Aspirate air out of catheter and check for flashbacks of blood. Then flush with sterile hep saline.
Stitch catheter in place.
Dress area with permeable transparant layer then soft dressing material.
110
What are some complications of jugular catheters?
- infection
- leakage of bloods, fluids, drugs (extravasation)
- thrombus/thrombophlebitis
- air embolism
111
What checks would we use to assess hypovoleamia?
BP, HR, pulse quality, mm colour and warmth of extremities
112
What is normal CVP in small animals?
Between 0-10cm H20
113
How do you convert mmHg to cmH20? When would we need to do this?
mmHg x 1.36 = cmH20
Electrical transducers when measuring arterial blood pressures in jugular catheters show CVP in mmHg.
114
How would you make a U manometer to measure CVP manually in practice?
Connect saline filled tubing to the jugular catheter and a 3 way tap.
Add saline filled tubing open to air which is secured upright with a ruler attached to 3 way tap. A bag of fluids in connected to the 3 way tap.
Make zero level on the ruler at the point of the heart (lat = point of chest, dorsal = point of shoulder)
Turn the three way tap open between air-top saline line and jugular catheter (off to fluids) and measure the distnace in cm between zero and top of saline. This is the CVP in cm H20.
Try and measure on exhale
115
When should we intervene with feeding?
After 3 days of anorexia
116
Ho do we calculate RER in canine patients over and under 2kg? and in a cat?
<2kg = 70 x BW^0.75
>2kg = 30 x BW + 70
cat = 40 x BW
117
What are suggested protein requirements for dogs and cats?
Dog: 2-3g/ kg of BW
Cat: 3g / kg of BW
118
What dose of diazepam can be used as an appetite stimulant?
0.05-0.15mg/kg IV
119
When should tube feeding be started?
If the patient is not meeting 75% of its RER
120
Describe when NO tubes would be used?
If teh patient isnt stable enough for GA as can be placed conscius and feeding tube isnt expected to be needed for more than a week. Liquid food only as thin tubes.
121
How are O tubes used?
Placed under GA,
can be offered food per os when theyre in. Wider tubes than NO so can have thicker food.
122
Where is a gastrotomy tube placed?
Directly into stomach, bypasses oesophagus.
123
Where is a jejunostomy tube placed?
Surgically placed directly into intestines to bypass stomach completely. Little and often food or CRI
124
What is parenteral nutrition?
Delivered via IV route bypassing the gut. Can be used to supplement enteral feeding if doesnt meet 50% of RER
Nutrition delivered aspectically via central venous catheter.
125
What are the risks of parenteral nutrition?
Thrombophlebitis of vein due to hyperosmolarity
Hyperglycaemia
Hyperammonaemia
126
