Fluid Therapy In Practice Flashcards by Anna Burrows

Describe hypovolaemia? What can you assess it based on?

•Loss of circulating volume (ECF). Can assess it based on:

–HR

–CRT

–PCV/TS

–Lactate

–Urine Output

Salt and water loss
Mainly seem in small animals, loss blood from ECF in circulation volume

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With hypovolaemia, how quickly should we aim to replace deficit?

Replace deficit 6-8 hours – want to get perfusion back to kidneys

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What is dehydration?

How quickly do we want to replace the deficit?

•Loss of body water (2/3 ICF and 1/3 ECF)

–Dec BW (not that useful unless we weighed it healthy previously!)

–Sunken eyes

–Tacky MM

–Inc skin tent

Replace deficit 12-24 hours
Just water loss – always hypernatremic

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What is the definition of shock?

Inadequate cellular energy production
Most commonly secondary to poor tissue perfusion

–Low or unevenly distributed blood flow

•Leads to critical decrease in oxygen delivery (DO2) compared to oxygen consumption in the tissues (VO2)

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What i hypovolaemic shock?

•Hypovolaemic (decreased circulating blood volume)

–Fluid loss from intravascular space

–Trauma

–Haemorrhage

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What is cardiogenic shock?

•Cardiogenic (decreased forward flow from the heart) – NEED TO BE CAREFUL WITH THIS TYPE OF SHOCK

–Congestive heart failure

–Cardiac dysrhythmias

–Cardiac tamponade

–Drug overdose (anaesthetic agents, beta-blockers, calcium channel blockers)

–One type of shock we sort of have to be more careful with when administering fluids as all of the other shock types, we can do the same thing with, but if suspect this, particular where we might have tamponade of CHF, if you give more fluid – forward flow made worse and back up of fluid within the heart

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Which type of shock is the only real type of shock that we need to be careful with adminstering fluids to?

•Cardiogenic (decreased forward flow from the heart) – NEED TO BE CAREFUL WITH THIS TYPE OF SHOCK

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What is distributive shock?

•Distributive (loss of systemic vascular resistance)

–Sepsis

–Obstruction (saddle thrombosis, heartworm)

–Anaphylaxis

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What is metabolic shock?

•Metabolic (deranged cellular metabolic machinery)

–Hypoglycaemia

–Cyanide toxicity

–Mitochondrial dysfunction

–Cytopathic hypoxia of sepsis

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What is hypoxaemic shock?

•Hypoxaemic (decreased oxygen content in arterial blood)

–Anaemia

–Severe pulmonary disease

–Carbon monoxide toxicity

–Methaemoglobinaemia

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What is cryptic shock?

•Cryptic (normal global circulation but poor microcirculation)

–SIRS

–Sepsis

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For all types of shock (apart from cardiogenic and perhaps cryptic) what is the mainstay of treatment?

Early recognition
Rapid restoration of CV function, quickly
Normalise tissue oxygen delivery as soon as possible
For all types of shock (except cardiogenic and perhaps cryptic)

–Mainstay:

Large volumes of IV fluids
Short, large bore catheters

–Ideally central or IO rather than peripheral vv

»But with canine and feline, often just need catheters as large as we can into both cephalic

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What are the clinico-pathological signs associated with <5% fluid deficit?

No clinically detectable signs

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What are the clinico-pathological signs associated with 5-7% fluid deficit?

Mild depression
Slightly prolonged CRT
Slightly increased heart rate
Increased blood lactate concentration
Creatinine concentration concentrated urine

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What are the clinico-pathological signs associated with 10% fluid deficit?

Depressed
May have cold extremities
Dry mucous membranes with a CRT >3 seconds
Heart rate >50% above the normal reference range
Increased blood lactate concentration
Increased creatinine concentrations
Small volume of very concentrated urine

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What are the clinico-pathological signs associated with 12-15% fluid deficit?

Depressed
Cold extremities
Dry mucous membranes with a CRT >4 seconds
Heart rates >100% above the normal reference range Increased blood lactate concentrations
Increased creatinine concentrations
Unlikely to produce any urine

Describe the 3 main options we have for fluid administration for circulatory shock

Option 1

•MBSA and estimate fluid deficit (L)

–BW x fluid deficit

Replace half the deficit as a bolus
MBSA (major body system assessment)
Replace the rest of the deficit, plus maintenance, plus anticipated losses over the next 6-8 hours

Option 2

MBSA and estimate fluid deficit
Provide a fluid challenge – depending what species you are
Repeat MBSA
Provide second fluid challenge
Repeat MBSA – estimate remaining fluid deficit and replace over 6-8 hours

Option 3

•Use pre-defined total shock fluid dosages

–Given to increments as required by the patient

–Or administered over 20-30 minutes

–This is the amount of isotonic crystalloids equal to the patient’s healthy blood volume

–Can administer large volumes quickly using

Pressure bags
60ml syringe on a syringe driver

What is the total shock dosage for ISOTONIC fluids in:

Dogs/horses/cows
Cats/small ruminants

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80ml/kg
50ml/kg

What is the total shock dosage for HYPERTONIC SALINE fluids in:

Dogs/horses/cows
Cats/small ruminants

Idk if we need to know these??

4-6ml/kg
3-4ml/kg

What is the total shock dosage for HYPERTONIC SALINE COMBINED WITH A SYNTHETIC COLLOID fluids in:

Dogs/horses/cows
Cats/small ruminants

Idk if we need to know these??

4-6ml/kg
2-4ml/kg

What is the fluid challenge for ISOTONIC FLUIDS fluids in:

Dogs/horses/cows
Cats/small ruminants

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20ml/kg
10ml/kg

How does colloids or hypertonic saline equivalate to Hartmann’s?

Colloids or hypertonic saline equivalent to 5x volume of Hartmann’s or other crystalloid
IE: 1litre of colloids/HS equivalent to 5 litres of Hartmann’s

What percentage of crystalloids stay in circulation after 1h after infusion?

•Only 25% crystalloids stay in the circulation by 1 hour after infusion

–Why may need to re-bolus

What type of fluid rates can lead to improved outcome particularly in animals with uncontrolled haemorrhage??

Research studies suggest use of hypertonic saline given as a slow infusion (0.4 mL/kg/min) versus fast infusion (1.33 mL/kg/min) leads to improved outcome particularly in animals with uncontrolled haemorrhage
During uncontrolled haemorrhage the infusion of only 1 mL/kg produced only a 20% mortality rate, versus an infusion of 4 mL/kg which produced a 50% mortality rate

With fluids and uncontrolled haemorrhage, what can improve tissue oxygen tension?

•The infusion of haemoglobin based oxygen carriers can improve tissue oxygen tension

What are pressors? How are they used in the management of haemorrhagic shock?

**_Fluids and pressors_** * Experiments in rats showed best survival (100%) with fluids and norepinephrine at 0.008mcg/kg/min titrated to a mean blood pressure of 80mmHg * 10x lower or higher doses of norepinephrine were associated with much worse survival (as was no norepinephrine) * A model where they hacked the tails off... * Titrating to blood pressure of 40mmHg with 0.008mcg/kg/min Norepi was better than any other group (90% survival) - other than the 80mmHg and medium Norepi group * Sometimes fluids need a bit of help, often have vasopressors such as NE and positive inotropes available and sometimes they just need this extra bit of help… if they are inappropriately vasodilated for example, just need a bit of help getting that BP up

What are the current recommendations for veterinary patients with uncontrolled haemorrhagic shock?

* Give moderate fluids until bleeding can be stopped using: * 1 ml/kg hypertonic saline and 2-3ml/kg/hr crystalloids if blood pressure cannot be measured * Keep mean arterial pressure as close as possible to 60mmHg, without increasing systolic pressure over 90mmHg * Consider low dose norepinephrine (0.01mcg/kg/min) or terlipressin (0.01mg/kg IV) * Don’t give no fluids, or large amount of fluids

If immedaite surgery is not an option, how do we deal with internal abdominal haemorrhage?

* If surgery not an option * Hypotensive resuscitation may be prolonged for several hours * Patients should be immobilised (secured to a back board) –treated with analgesics and anxiolytics •Bleeding from the abdomen, pelvis or femoral area (as indicated from clinical signs, US, radiographs etc) –controlled by mildly applied counterpressure to affected area * Counterpressure applied with towels and tape and limited to 10–15 cm H2O (measured with a partially inflated BP cuff under the towels) * Pressure is gradually removed after several hours to allow clot stabilisation * Immobilisation is continued for several more hours and tissue perfusion is closely monitored * NOT for thoracic haemorrhage

What is the treatment for traumatic brain injury including fluids?

•Initial extracranial stabilisation takes place first –Correction of tissue perfusion deficits, typically as a result of hypovolaemia –Optimising systemic oxygenation and ventilation •Goals for intracranial stabilisation include –Optimising cerebral perfusion –Decreasing ICP –Minimising increases in cerebral metabolic rate • •Fluid therapy –Fluid restrictions in these cases are contra-indicated •It does not reduce or prevent cerebral oedema –What to use •Either ¼ aliquots of ‘shock’ rates –15-20ml/kg boluses of Hartmann’s –2.5-5ml/kg Colloids •Evidence that 7.2% hypertonic saline good option –Rapidly restores circulating volume –Also increased osmolarity draws fluid from interstitium thus decreasing oedema –4ml/kg over 3-5 mins –Follow with crystalloids •Hyperosmolar therapy –Mannitol for severe TBI and progressive neurologic deterioration –First-line therapy for decreasing ICP and improving CPP –0.5 to 1.5 g/kg as a slow bolus over 15–20 minutes –High-dose (1.4 g/kg) better neurologic improvement compared with low-dose (0.7g/kg) –Hypertonic saline may be better * 4ml/kg 7.2% over 3-5 mins * Lasts longer then mannitol and reduces ICP more

You are presented with a 15 year old 500Kg TB gelding that has signs of abdominal pain Horse obtunded, MM dark pink with CRT 3 seconds, HR=80 BPM, skin tent \<2 seconds, RR=20 BPM and T=36.8oC, no borborygmi 1. What is the horses fluid deficit? 2. Route of adminstration? 3. What are you going to do initially? 4. Then what regarding fluids?

•What is the horse’s fluid deficit? –10% –In litres – 50L •Route of administration? –Central jugular –Don’t give fluids orally when impaction suspected – wont have great absorption. –No borborygmic – likely no blood flow •What are you going to do initially? –Pass NG tube –Rectal exam •Then what regarding fluids –Fluid options: •Almost everything can have Hartman's but doesn’t come in 5L bags, so not the best idea –Fluid challenge –MBSA and estimate fluid deficit. BW x fluid deficit. Replace half deficit –Deficit = 500 x 0.1 = 50L –25L as a bolus –Then replace other 25 as maintenance over next 6-8h after MBSA. Include ongoing losses and maintenance – so maybe 35L over 8h –Could give 2L hypertonic then could follow this with 10 or 15L of Hartman's and then do as above for next 6-8h

Presented with a 3 year old male castrated domestic shorthair cat The cat is straining and has not urinated HR=90BPM; RR=30BPM; T=38oC; MM pink with CRT 3 seconds; skin tent of 5 seconds 1. Provide an assessment and likely diagnosis in this animal 2. How will you proceed? 3. Fluid therapy plan?

* Likely to be both hypovolaemic and dehydrated. But why is its HR 90? As its likely to be hyperkalaemia as its probably a blocked cat! * next – palpate bladder * Cysto come of it off * Fluid therapy –Could use NaCl? Controversial these days – its very acidifying, can cause more K+ to come out of cells – could argue could use Hartman's in these cases –Calcium gluconate –Glucose and insulin •Glucose at least 5% but probably more than that –Going to give fluids at 10mk/kg fluid challenge and probably going to need to repeat this –Its also dehydrated, so can go steadier with rate as going to want to let fluid move back into the interstitial and intracellular spaces •As dehydrated – hypertonic saline not an appropriate choice

500Kg 18 month old African elephant Obtunded; HR=160BPM; RR=24BPM and T=39.5oC CRT=3 seconds; distended jugular veins; no obvious skin tent Washing machine sound over the cardiac apices 1. Estimate this animal’s fluid deficit 2. Route of administration? 3. IV access proved problematic to maintain……What other routes would be appropriate?

* Fluid deficit – around 12-15%! This was a case of elephant herpes virus and causes pericardial effusion * How to give fluids – auricular vein, cephalic = VERY HARD TO GET IV IN ELEPHANT!! Lateral saphenous if they are well behaved if a good option –Could give rectal fluids? Fluids that aren’t absorbed orally seem to be absorbed effectively rectally – so wont get big fluid rates that you want but can maybe get 2-3x maintenance per rectum whilst faffing about trying to get IV line in. another option to consider or if finances don’t allow for large IV volumes

* You are presented with a 600Kg 4 year old HF cow with anorexia and complete cessation of milk production * Absent ruminal and GI motility * Ping on the right in the 8th ICS * HR=120BPM; RR=40BPM and T=38.3oC; Lactate=8 mmol/L 1. •Likely diagnosis? 2. •Assess fluid deficit? 3. •Fluid plan? 1. –Route? 2. –Finances?

* Likely diagnosis – RDA * 10% -12% deficit, roughly 60L * Route of administration * Ideally IV * Enteral route wont be absorbed and might make obstruction worse * Financially – to make affordable * 4ml/kg hypertonic (12equiz 15L Hartman’s * Or make them yourself!! From sterile water and electrolytes

* You are presented with a 5Kg Belgian hare that was found this evening collapsed * It is a hot August day and the animal’s water bottle has blocked * HR\>250BPM; RR=48BPM and T=35.3oC; MM pale – no CRT; skin tent very prolonged 1. •What is your likely diagnosis? 2. •What are you going to do next? 3. •Fluid type? 4. •How will you administer fluids in this animal? 5. •Other clinical scenarios

* Likely diagnosis – gone into shock, so has peripheral shut down * Fluid to give and how to give it * We have probably got hypovolaemia and dehydration * HR high along side markers or dehydration * Route of admin – ideally IV * Deficit in this bunny – 15%, looking at about 750ml – going to give this to a bunny via IO catheter as may struggle to get this through the ear vein * Speed of fluids – prone to developing pulmonary oedema if we don’t have normal lung dynamics. Fluid challenge is a good option and this then means that you want to give it slowly, want to resort IV volume but give him time to put some of that fluid into interstitial space.

* 30Kg Labrador presents following an RTA. Dog has fractured forelimb and bleeding from the brachial artery region that was bandaged at the scene * You ligate the bleeding vessel * There are no other obvious areas of bleeding * The dog is in lateral recumbency, has pale mucous membranes, heart rate is 120 beats per minute and is panting 1. •What would you estimate the dog’s fluid deficit to be? 2. •What will you initially administer and how much? 3. •Then what regarding fluids?

* Deficit – 8-10% * Fluid choices we will have * Hartman’s * Blood would be other choice – this is a colloid, cannot give this at quite the same speed. Go steady with a blood transfusion to see if we are going to get a transfusion reaction. * Start with Hartman’s and then think about blood? * As we have stopped the bleeding, can treat as other cases

* 60Kg Great Dane fallen from a roof garden * Dog is pale, HR=130BPM, pale MM, cold extremities, significantly increased respiratory rate * Abdomen is distended –You suspect a haemabdomen 1. •What is this animal’s fluid deficit? 2. •How will you replace this? 3. •What will be your aim?

* Deficit 10% roughly, maybe 12% * So 6 L deficit * Animal that we are going to want to do permissive hypotension on * Start with 20ml/kg boluses and monitor BP if possible, if you cannot, make sure you can feel dorsal pedal artery but that it wasn’t too pronounced, as it disappears at a mean BP of 55 * 20ml/kg boluses of Hartman’s until looks stable enough to take to surgery * Might belly wrap him to see if can provide some additional support * Try and auto transfuse this dog during surgery – as long as no GI contamination!! * Aim is to get it stable for surgery