Today is a first for the podcast - we’re using a case study to discuss how we can provide even better care to our haematology patients!

From performing initial diagnostic tests to running a blood donation and transfusion and everything in between, we’ll break it all down in this episode - so you can walk away and give confident care to your own haematology patients.

Meet your case…

I’m excited to introduce you to my all-time favourite haematology patient, Stevie Nicks. He’s a 2-year-old MN DSH with a very long history of haematological disease, starting at just 9 months old.

We diagnosed Stevie with precursor-targeted immune-mediated anaemia, aka PIMA. This is an immune-mediated disease similar to IMHA, but unlike IMHA, where the immune system attacks the circulating red blood cells, in PIMA, the immune system attacks the bone marrow and the cells that will ultimately become RBCs.

Since diagnosis, Stevie has had complex treatment, including various immunosuppressant medications, multiple blood transfusions (including a xenotransfusion) and a splenectomy.

Stevie was re-presented for an urgent assessment as he was quieter than usual at home. 

We triaged him and found:

• Tachycardia (HR 220 beats/minute)

• Tachypnoea (RR 48 breaths/minute)

• Pale MMs with a slight icteric tinge

• Quiet mentation

• A heart murmur

We took bloods and found that his PCV had reduced to 15%, with a normal total solids of 65g/L.

So what does this tell us?

Yes, Stevie’s PCV has dropped - but more importantly than that, his cardiovascular system is showing that he’s not coping with that anaemia right now. 

We never want to decide to transfuse based on just the PCV - we need to look at our patient, too, and ask ourselves, “Are they clinical for this anaemia?”

Look at your patient’s perfusion parameters - their heart rate, respiratory rate, blood pressure, pulse quality and mucous membrane colour/CRT. If they’re showing signs such as tachycardia, bounding pulses, bradycardia, weak pulses, tachypnoea pale MMs or hypotension, there’s a good chance that a transfusion is indicated.

Based on this assessment, Stevie needed a transfusion to restore his oxygen-carrying capability and perfuse his cells and tissues.

But before we do this, there are a few things we need to think about, including:

• The blood product he needs

• His transfusion history and risk of a transfusion reaction

• Finding a suitable donor

• His monitoring and nursing care requirements

So what will we transfuse Stevie with?

We know that Stevie is anaemic, so we will need a product containing red blood cells. Our options are whole blood (fresh or stored since he is not thrombocytopenic) or packed RBCs.

In his case, given that he’s anaemic but not hypoproteinaemic, packed RBCs would be the most suitable option for him - but they’re also notoriously challenging to find in the UK, as we don’t have access to banked feline blood products.

This meant that the only option we had for Stevie was a fresh whole blood transfusion, collected immediately prior from a donor cat.

What do we need to think about when finding a suitable donor?

As nurses, advocating for our donor cats is just as important as advocating for our recipients.

Nurses are often involved in (or even run) the donation process, so it is essential to find a suitable donor with minimal donation risks.

The ideal feline donor should:

• Be 1-8 years old (ideally 1-5 years old)

• Have no significant previous medical history

• Not be on any medications (except preventatives)

• Be up to date with vaccinations and parasite prevention

• Weigh at least 4.5kg (lean weight)

• Not be raw-fed

• Not have travelled overseas

• Never been used for breeding

• Have indoor-only access (or confirmed FeLV/FIV negative if  they have outdoor access)

• Have an excellent temperament and good veins!

Once you’ve selected an appropriate donor, we need to do some tests…

We know that donation is a procedure that carries risks not just to our recipients but also to our donors.

We’re sedating them (in most cases) and taking around 10-12% of their blood volume - and we need to make sure it’s safe for us to do so.

In addition, we need to ensure that our donor doesn’t harbour any infectious diseases that could be passed on to the recipient.

A biochemistry and haematology panel is run before donation, and a normal PCV is confirmed on donation day. In addition, the donor needs to be blood-typed (if their blood type is unknown) and tested for FeLV, FIV and mycoplasma haemofelis.

In addition, donor cats should have a point-of-care echo performed to assess for occult cardiac disease, which could be exacerbated by donation.

In Stevie’s case, we needed a type A donor who was cross-match compatible (Stevie is a blood type A). This was essential since Stevie’s previous transfusions stimulated his immune system, causing him to produce antibodies that increase his risk of reactions to future blood products.

Let’s meet our donor, Desmond.

Desmond is a 1.5-year-old MN DSH with no previous medical history besides routine preventative healthcare. He is also a 5.3kg, very chilled-out boy!

His pre-donation testing was normal, and he was confirmed as type A.

We then performed a major crossmatch, combining Desmond’s whole blood with Stevie’s serum - and this was compatible, demonstrating that Stevie could safely receive Desmond’s blood.

Ok, so we’ve got our donor - how will we perform the donation?

Feline donations are generally performed under sedation. When selecting a sedation protocol, try to avoid drugs that cause significant cardiovascular depression - I often find donation is more challenging in patients who’ve received alpha-2s, compared with drugs like butorphanol, alfaxalone, and benzodiazepines.

Once the donor is sedated, the jugular vein is clipped and aseptically prepared, and 10-12ml/kg of whole blood is aseptically collected.

There are two methods of donation: the closed method, which is free of contamination as the donation is performed within a closed system, and the open method, which uses multiple anticoagulated syringes and a 3-way tap.

Once the donation is complete, the donor can recover and be discharged, after which they must refrain from donating again for another 2-3 months.

Desmond’s donation

Desmond was sedated with butorphanol, alfaxalone and midazolam and 55ml of blood was collected from his jugular vein using the open collection method. He recovered well and went home later that day.

While he tucked into a post-donation meal, our nurses began preparing and administering his blood to Stevie.

How will we give Stevie his transfusion?

First, we need to prepare Desmond’s blood for administration and make Stevie’s transfusion plan.

Let’s talk preparation

Wearing sterile gloves, the first donated syringe was run through an in-line blood filter and extension set for administration with a syringe driver.

The remaining syringes were stored upright in the fridge and taken out as needed. Each syringe was allowed to come to room temperature before administration, before the plasma was separated and discarded. This allowed us to turn our donated syringes into packed RBCs, minimising fluid overload.

And then how much will we give Stevie?

We usually give between 12-20ml/kg whole blood or 6-10ml/kg packed RBCs, depending on the individual patient and the severity of their anaemia.

There is a calculation that tells us exactly how much of our donated blood our patient needs:

Volume needed (ml) = (weight x 60) x (Desired PCV - Current PCV)/Donor PCV

In Stevie’s case, we calculated that around 60ml of Desmond’s blood would raise his PCV by 10%, so he could safely have the whole 55ml donation.

Once the donation volume has been calculated, it’s time to plan the transfusion rates.

We always want to start at a low rate initially, when the risk of transfusion reaction is highest. In Stevie’s case, we started at 0.5ml/kg/hour for the first 15 minutes, increasing to 1ml/kg/hour for the next 15 minutes. We then administered the remaining volume over 5.5 hours, allowing us to deliver the entire transfusion over 6 hours.

What about transfusion monitoring?

We assessed Stevie’s TPR, MM, CRT, non-invasive blood pressure, and ECG before the transfusion began and noted his plasma colour.

We housed him in an area where he was continually monitored and attached him to non-invasive monitoring, which allowed us to assess his response to the transfusion in a stress-free way.

After beginning the transfusion, we repeated these vitals every 5-10 minutes initially and then reduced them to every 30-60 minutes as his transfusion progressed with no signs of reaction.

We also avoided feeding Stevie during his transfusion and adjusted the timings of his non-critical medications to after the transfusion had finished.

And what about transfusion reactions?

Luckily, we didn’t see any transfusion reactions in Stevie’s case due to careful donor selection, crossmatching, and careful preparation and handling of the donated blood. But what should we be looking out for?

When I’m monitoring transfusions, these are the things that spark a red flag for me:

• Sudden increases in heart rate, respiratory rate or temperature

• Increases in vital parameters over time not attributed to stress or other environmental factors

• Changes in respiratory pattern or effort, signs of respiratory distress

• New jaundice

• Abnormal or sudden behaviour changes

• New onset vomiting not attributed to existing disease or a recent meal

• New haemolysis on blood sampling (e.g. for PCV measurement)

• New haematuria (haemoglobinuria) or pigmenturia

• New arrhythmias (not caused by anaemia)

And then, as we discussed in episode 46, if you’re worried about a transfusion reaction, the AVHTM guidelines are a fantastic resource.

So that’s Stevie’s transfusion - but what about his nursing care?

Stevie’s nursing was very hands-on, and there are a lot of skills that we can use with haematology patients like him!

Alongside running Desmond’s donation and collecting the blood, our nursing included:

• Careful monitoring of Stevie before, during and after the transfusion

• Processing lab samples, looking at blood smears, performing in-saline agglutination tests and crossmatching

• Feline-friendly nursing care

• Nutritional support

• Monitoring hydration and perfusion status

• Managing venous access

• And much more!

These are just a few of the nursing skills our haematology patients benefit from - in reality, there are many more ways we can use our skills and knowledge to improve the care patients like Stevie receive.

Did you enjoy this episode? If so, I’d love to hear what you think. Take a screenshot and tag me on Instagram (@vetinternalmedicinenursing) so I can give you a shout-out and share it with a colleague who’d find it helpful!

Thanks for learning with me this week, and I’ll see you next time!

References and Further Reading

• Day, M. and Kohn, B. 2012. BSAVA Manual of Canine and Feline Haematology and Transfusion Medicine. Gloucester: BSAVA.

• King, L. and Boag, A. 2014. BSAVA Manual of Canine and Feline Emergency and Critical Care. Gloucester: BSAVA.

• Merrill, L. 2012. Small Animal Internal Medicine for Veterinary Technicians and Nurses. Iowa: Wiley-Blackwell.

• Odunayo, A. et al. 2021. Association of Veterinary Hematology and Transfusion Medicine (AVHTM) transfusion reaction small animal consensus statement (TRACS). Part 3: Diagnosis and treatment. Journal of Veterinary Emergency and Critical Care, 32 (2), pp. 189-203. Available from: https://onlinelibrary.wiley.com/doi/10.1111/vec.13043

• Obrador, R. et al. 2015. Red blood cell storage lesion. Journal of Veterinary Emergency and Critical Care, 25 (2), pp. 187-199. Available from: https://onlinelibrary.wiley.com/doi/10.1111/vec.12252

• Taylor, S. et al. 2021. 2021 ISFM Consensus Guidelines on the Collection and Administration of Blood and Blood Products in Cats. Journal of Feline Medicine and Surgery, 23 (5), pp. 410-432.