So welcome everyone. Thank you so much for joining us tonight. I'm really, really excited to have somebody discussing this topic.

Transfusions was something that I had on my wish list for a long time, and we finally get to make that come true. My name is Doctor Kirsten Roren. I'm the consulting veterinarian for Medi Pets Pet Insurance, and we are very thrilled to have Simon here to give you guys some smarts.

On transfusions and so just a couple housekeeping things to start out with if anyone has questions for Simon please if you could put them into the Q&A box at the bottom we're gonna save the chat for things like questions or comments and we'll try and kind of keep up with those but then what we'll do is we'll come back and try and answer as many questions as we can at the end of the talk. So again. If you do have questions for Simon, please put those in the Q&A box.

A quick word, I will try and keep this brief, but a quick word from the vet team at Many Petts, we just wanted to say thank you for everyone again for joining us and also thank you so much for all of the really productive feedback and conversations we've been having with you guys over the last 6 to 12 months. I'm really proud of my team. It's me and .

Three other very lovely human beings who I hope are on here. I think they are, Claire, Charlotte, and Jackie, if you have not had a chance to get to know any of us, please come see us at events. We love to meet you.

We love to get to know you and we love to support you, and that is one of the reasons why we're here. So going, being able to go to these things and do things for you guys to kind of give back and support your, your growth as veterinary staff, so. Thank you again.

And then next up I'm gonna do a quick bio for Simon, and then I will let him take it away because you are not here to listen to me. You are here to listen to him. So Simon trained at University of Cambridge and after qualifying, he spent 2 years in small animal practise before taking up a residency in small animal medicine and intensive care at University of Bristol.

He joined DWR in 2007. Which I was just telling him, I, I had the pleasure of driving past this weekend. I was near Cambridge and it was lovely out there.

He holds the Royal College certificate in animal medicine and the European Diploma in Veterinary Internal Medicine and as an active member of BSAVA and was the editor of their companion journal for 5 years, Simon particularly enjoyed. Critical care and has been instrumental in developing the interventional radiology service at DWR using minimally invasive techniques and biomaterials to treat many conditions which previously required more invasive surgery. He has lectured widely in the UK and Europe on subjects including emergency medicine and interventional radiology.

And tonight, a subject that is near and dear to my heart. Please, Simon, we would love for you to teach us how to not be afraid of transfusions in general practise. I know I used to be and I've come a long way, but I'm excited to hear all of your tidbits.

Perfect. Thank you very much, Kirsten, and, welcome everyone to tonight's, webinar. We're gonna talk about blood transfusions.

We're gonna talk about when we give them, how we give them, and, why we give them. So, thank you very much to the Pet Blood Bank for sponsoring tonight. And, oh, sorry, there we go, and to many pets to Pet Insurance who are the other sponsors.

So we're gonna go through, a number of things. We're gonna talk about when and why we give blood transfusions, and we'll talk about what products we have available to us. So we'll talk about whole blood, and then we'll talk about some of the products that we can get from the blood bank in terms of pat red cells, plasma, so both thrush.

Frozen and frozen plasma, cryoprecipitate, and we'll just touch on the platelet products. So, most of the time when we're giving platelets, we'll give whole blood, but we also have platelet rich plasma available, occasionally in terms of when we'd want to use that for transfusions for thrombocy peanut patients. And then we'll talk about the practicalities of how we actually do it, which is always the difficult thing.

I work in a big practise, we have a busy emergency department. We give blood transfusions probably every day, to some of our patients, which is fantastic to have the link up with the pet blood bank. To be able to, to give those, transfusion products.

But if it's your first time or you've not given a transfusion for a while, then it can seem a little bit tricky, and we worry about doing that. We know blood is a precious commodity when we've got it, and we don't want to, to waste or to get that, transfusion wrong, and we don't want to have difficulties in terms of giving the transfusion. But it is one of those things that once you understand what's happening, is relatively straightforward to do.

We shouldn't be afraid of giving blood transfusions. Chances of having issues with blood transfusions are very low. We do say transfusion reacts.

But significant ones are, are very few and far between if we manage to, type and, cross match patients effectively when we need to do that. And it's relatively straightforward, and obviously has a big impact on patients when we need to give them transfusions, when we're thinking about anaemic patients and giving red cells to increase their oxygen carrying capacity, and we're plasma for patients that have coagulopathies or we want to, to try to help to improve their albumin levels, for example, in smaller patients to, try and make a big difference there. So we'll talk about how we collect blood, how we store blood, how we might utilise products that come from the blank.

Talk a little bit about blood typing both in cats and in dogs. We'll talk about cross matching, and then we'll finish off talking about the blood administration in terms of how we give the blood and the practicalities of actually physically doing that within practise. So to start off, I just wanted to introduce you to a patient.

This is a little dog called Tapo, who's a 4 year old cocker spaniel that I saw, not too long ago. He'd been, very well, until a couple of days, before we saw him, and he'd started to just become progressively a little bit lethargic, a bit weak, just not being quite right, for a few days, and the owners had made an appointment to see their own local vets, the day we saw him. But that morning he'd collapsed and been unable to stand.

And the referring vets very quickly realised that this was something that was gonna require a little bit more specialist input, so they referred him to us for further investigation. When we saw him, we could see that he was very weak, he wasn't able to stand. Examining, you could see that he's got very pale mucous membranes.

They're, they're very white in terms of, of the coloration. And he had very bounding peripheral pulses, so very bouncing pulses, and a new onset heart murmur which hadn't been noticed previously. And we often see that when we have patients that become anaemic, rapidly, where there's turbulence of blood flow due to their lower red cell numbers.

So looking at him we'd be concerned that this is a potential anaemia, given that the coloration is suggestive of that. It could be that this is just very marked shock, but we'd want to try and understand that and be able to look at things in a little bit more detail. So doing some emergency blood work enables us to do that.

And a PCV showed that his red cell numbers were very low, so hematocrit of 12, PCV tube was 12, so there's a lot less red cells in the circulation we would expect. So normal PCV should be in the region of 35 to 45, so we've got about a third less red cells than we'd expect. And obviously that's happened very quickly, so we do not have any time to adapt that anaemia, so it's gonna cause the signs, and the weakness and the lethargy that we're seeing.

So when we have anaemia and we have low red blood cells like that, we know that there's sort of three main groups of of things that can cause the red cell numbers to be low. We can lose red cells, so we have haemorrhage or loss, we can have red cell destruction, so they're being taken out of the circulation by the immune system or being destroyed for some reason. Or we may not be able to produce red cells for some problem within the bone marrow, for example, that's causing a problem.

So things like myelofibrosis or neoplastic conditions. When we have acute onset conditions like that, normally production takes a while. We know red cell production in the dog is about 60 to 90 days, so it takes a little bit of time for for anaemia to develop, and this is very acute onset, so it's making us think of blood loss or potentially red cell destruction.

And there isn't any obvious sign of Tappo, that he's lost red cells, he's not bleeding, so we can see that. He could be bleeding into a body cavity and point of care ultrasound would be very helpful to try and understand that. But being a cocker spaniel, we're worried about red cell destruction from the point of view of immune mediated disease.

We know that that's probably the most likely given the breed, and when we're looking at his blood smear, which is over here, we can see that there's, polychromasia, so changes in red cell shape and size, which is suggestive that this is a regenerative anaemia, but there are also some sarrocytes that we can see as well. So we've got these, very, dark looking red cells which adhere to these assherocytes, these dark cells that don't have the area of central pallor, in the middle of the red cells, which, indicate that they've had, a chunk of the membrane taken away, so the immune system, phagocytosis that, membrane, and they've got the same amount of haemoglobin. So rather than being that sort of doughnut shape, red cell, we've got a, a spherical ball which, when we look from the top looks darker, rather than that area of pallor in the middle.

Few other reasons why we could see red cell destruction. So Barbezia, for example, in the UK there are a couple of pockets of that, but it's not an endemic disease in the UK, and then toxins, so things like zinc, from foreign bodies, metallic ones, or onion toxicity. So, you know, dogs that scavenge, onion bargis and.

Things like that can sometimes have problems. And then changes in phosphate, not so much in, dogs, but in cats, changes in phosphate, usually associated with refeeding syndrome. The osmotic fragility of red cells is much lower, so those cells potentially can rise if phosphate changes, but it's not something we see very often.

So with Tapo looking at his blood smear, we're obviously concerned that this is a newmediated disease and then there's red cell destruction. And looking at the, rest of his blood work, so looking at the, oh. Picking up the Rest of the smears in terms of where we are, we can see that we've got changes associated with red cell glutination.

We've got er changes where the red cells are all stuck together, and this is an inside saline and glutination test. We've got one drop of saline and one drop of blood, and you can see all the red cells are, are stuck together. And then over here in the PCV tube we've got the red cells at the bottom, but you can see that it's hemolysis.

The plasma is very red-tinged because we've got free haemoglobin within the circulation. So the red cells have lysed through that IMHA process. So we have a dog that has a very low number of red cells and problems as a result of that, and we want to try and increase the oxygen carrying capacity and increase the red cell numbers, but obviously protect those from being destroyed.

So we're gonna think about steroids and looking for causes of the immunemated disease, so infectious things, looking for cancers, chest x-rays, abdominal ultrasound, and all of those sorts of things. But in this instance, trying to make a difference in terms of increasing the red cell carrying capacity and increasing the number of red cells in the body is gonna make a big difference. So why do we give red cells and, and when do we think about giving them?

Well, we want to improve that oxygen carrying capacity, we want to increase the number of red cells that are present in the circulation. And we do that when red cell numbers change very quickly. So that can happen when we have acute bleeding, and when we have blood loss where we lose more than 25 to 30% of the blood volume very quickly, we're gonna see that the body isn't able to cope with that.

And then when we have an anaemia, we'll think about transfusion when the red cells get to a level which is gonna precipitate the body having problems as a result of that. So usually we're thinking about transfusion patients when their PCV is below about 15. It may be we transfuse them before that if the speed of onset in that anaemia has got, got very rapid, and want to try and increase the red cell carrying capacity to, to increase the amount of oxygen that we can take to tissues.

If the anemia's developed over a long period of time, then there are physiological things that can happen in the body that allow the body to improve and to the red cells to give up oxygen at lower oxygen tensions. So the levels of T3 GPG for example increase. So for example, if we did have one of those bone marrow problems where the PCV had got low.

Maybe to 8 or 10%, but over a number of weeks, then the body would have coped with that. And we may not have seen physiological problems associated with that. So we may be able to see that the, the animal is coping a lot better.

Whereas if you've been hit by a car and lost half of your blood volume, then you're not going to be coping with that change, quite as easily because there aren't physiological adaptions. So when we give a transfusion, really depends on how that patient is and how that patient is managing. So what the perfusion is like, what the cardiovascular system is, is telling you in terms of how that patient is coping with the anaemia that's there.

Because if it isn't coping, the heart rate is gonna come up and we're gonna feel that the peripheral pulse quality is gonna get quite bouncy and the demeanour of that patient is gonna be less than we'd expect that patient is gonna be less less lethargic and less responsive, and that's gonna be an indication that we're gonna be wanting to transfuse that patient sooner rather than later. And I'm very lucky to work in an institution where we've got the packed red cells within our fridge and we can transfuse patients very rapidly if we need to. So sometimes we do sail perhaps a little bit closer to the wind with things, in terms of, of the patient managing and then transfusing.

But if there's any doubt, transfusing sooner rather than later if it's gonna take you time to order that product and be able to get it into the practise, would be the best way forward. So this is what I was talking about in terms of oxygen delivery. We need oxygen for our tissues, for those tissues to undergo aerobic metabolism to produce the energy that all of the tissues need to function effectively.

An oxygen delivery to the tissues is made up of two components and. Sorry to show you equations in the early part of a, a talk, but I think they help to understand what's happening, where oxygen delivery is the, product of the oxygen content of the blood, so how much oxygen is carried by the haemoglobin and the red cells multiplied by the cardiac output. So essentially the volume that's being.

Pump from the heart. So that's the heart rate times by the stroke volume. So, if we're wanting to get oxygen around the body, we need to have oxygenated blood, oxygen oxygen content bit, and then the cardiac output.

So essentially ventilation, how well oxygenated the blood is, and perfusion, how well your body is, is able to pump the blood around. And the oxygen content part of the blood is made up of two parts. We've got the oxygen that's carried by the haemoglobin in the red cells, and then a small amount of oxygen which is dissolved in the plasma.

Now by far and away the biggest part of the oxygen carrying part of the blood is what's attached to the haemoglobin. The partial pressure of oxygen here times by 0.003 is gonna be a very, very small number and the amount of oxygen that we have in, in the plasma is very low.

It's not physiologically going to be able to, to provide oxygen for the tissues, but it's what we measure when we do arterial blood gases. So physiologically, that's the best measure of where we are with oxygenation. But the amount of haemoglobin that we have is obviously very important, so that's the other part that's here.

So 1.34 times the haemoglobin times its saturation. And the saturation is what we measure with our pulse oximeter, how saturated the haemoglobin is.

The haemoglobin is obviously how much haemoglobin we have in terms of whether the patient is anaemic or not. And then the constant at the beginning is, is the affinity of the haemoglobin for oxygen. And that will be higher when we have neonatal haemoglobin or foetal haemoglobin, and it will be lower if we damage the haemoglobin.

So for example, if we have carbon monoxide poisoning, then there's gonna be less affinity for the haemoglobin for oxygen, we have less oxygen carrying contents. So the amount of haemoglobin we have and how saturated is, is gonna make a big difference to the oxygen content, and that oxygen content is then gonna make a big difference to where we are with auction delivery. So if we have very anaemic patients, they're gonna find it a real difficulty to be able to deliver the amount of oxygen that we need to the tissues for those tissues to be able to function effectively.

So giving blood transfusions in this instance is gonna be very effective. This is Tappo receiving a blood transfusion very quickly after he was admitted into the hospital because he was struggling as a result of that. And we'll talk about how we give blood, and we'll talk about the different blood products we have.

This is Pat Red cells from the pet blood bank in terms of being able to, to rapidly give a transfusion to make a difference for him. We monitor him very closely in terms of making sure that there are problems as a result of that. And he was much more stable as a result of the blood transfusion.

We obviously wanted to protect those red cells, make sure they weren't destroyed, and look for underlying reasons as to why there might be problems, and he developed immune mediated disease. But in that instance, we were able to find that this was straightforward and IHA and we were able to, to treat him very effectively in that regard, and that blood transfusion very rapidly, made things a lot more stable. And we were able to, to go ahead and and be able to, to do those investigations afterwards.

So, blood will make a a massive difference in those situations and being able to give that quickly improves that oxygenation for the tissues for allowing us to, to do further investigations and to understand what's happening with those patients. So when we're thinking about giving blood transfusions, there are a number of different products that we have. So we have whole fresh blood, which is where we take blood from our donor and immediately give it to our patient.

And we can do that in practise if we have blood donor. So my dog is a blood donor, she comes to work sometimes to to be able to give whole fresh blood transfusions, and we take the blood and immediately give it to our patient. And when we think about cats at the moment, in the UK whole fresh blood is the only way essentially of doing transfusions in other parts of the world, we do have a blood banking for for cats, but we're not quite there yet, in terms of what we're able to, to do in the UK.

But with dogs, we're able to take blood, and we can give that whole fresh blood transfusion. Or we can use a blood bank. And the blood bank is, a really good way of, of stratifying the, blood that is taken into products that we can then use for different things.

So we can take the red cells from that transfusion and use them for anaemic patients, and we can use the plasma and use that for patients that have coagulopathies and problems with their blood clotting. So we can process that blood, spin it. Down, take the red cells, and then use the, the plasma separately.

So having a blood bank enables you to have products that you can store. You can add lifespan extenders to the red cells so they can stay in the fridge for a little bit longer, and we can freeze the plasma where it can stay in the pla the, in the freezer for 1 year as fresh frozen plasma or up to 5 years as frozen plasma, and then we can utilise those products as and when we have a problem, and we have a better resource to be able to do that. And if you're in the UK using the pet blood bank, then you can get products very quickly by courier, so the same day or overnight delivery, and that means you can utilise those in those patients, very, very rapidly.

So it's a, a really good way forward. And there are also the, the blood sharing schemes where some of the bigger referral centres, cells, other centres will be able to, essentially help you, if you need blood, they will store blood. The obligation is that if there's a need somewhere, you can go to that centre, collect the blood, and then that will be replaced.

So you contact the blood bank and they, organise that for you, you pay for the blood unit to be redelivered to the centre that you've borrowed it from. So those things work really nicely where there are centres where you can, essentially utilise those products a little bit more effectively. So transfusion products, are really nice ways of being able to use stored products in a much more effective way.

And we can use those to then produce some other sort of more specific products. So fresh frozen plasma we use in coagulopathies, but we can spin that down to be able to have cryoprecipitate, which has, essentially a smaller volume, but, the same amount of of the advance factor factors, factor 8, for example, for some of the coagulopathies, and we can make platelet rich plasma. So when we're wanting to transfuse platelets, that's a very good way of addressing, platelet problems.

So we won't talk too much about that this evening, so we're talking about blood transfusions, but platelet rich plasma is available from the blood bank as well. So when we're thinking about whole blood, essentially where we would take blood from our donor and give it immediately to our patient, it would contain everything that we would expect it to. So the red cells, obviously very useful when you've got anaemia, does have some platelets, although they clot quite quickly, so the amount of platelets in a whole fresh blood transfusion is gonna be quite low, but it is an effective way of us, giving some platelets to stop bleeding or problems associated with that.

Have all the clotting factors, so all the ones that we would expect, including Bovilavan's factor, and then it does have Almin. The only thing that we don't tend to talk about and and find useful with hot blood transfusions is white blood cells. Those tend to cause transfusion reactions or problems if they lie, so rather than the useful things that we can transfuse into a patient that will have an effectiveness in that patient.

So it's essentially the red cells, the platelets, and then the clotting factors proteins that we're, we're thinking about. So when do we give whole blood? Well, essentially when we've lost whole blood, we want to give it, so anaemia, surgical bleeds, or, you know, quite large volume of, of blood loss associated with external haemorrhage, which would be a really useful way of, of replacing like with like.

Or when we've got thrombocytopenia, if we don't have access to the platelet rich plasma, we can give whole fresh blood transfusions and that will help us to increase the platelet numbers. But 10 mL per kilo of whole fresh blood, which usually raise the PCV by about 5%. We'll raise the platelet count by about 10 times 109.

So it's not gonna be enough to take your platelets back to a normal level or increase them significantly as you would with platelet rich plasma, but it may be enough to stop bleeding. So if you've got intracranial haemorrhage, or you've got GI bleeding, then it may be enough to limit that and help to stabilise things whilst you're looking for other products or other reasons or starting other treatments to be able to get things under control. And then to replace clotting factors.

So if you've got a, patient that is coagulopathic, then a whole fresh blood will be a good way of, of trying to stop, bleeding and replace those clotting factors, especially if you've got, haemorrhage associated with that. But obviously, if you've got the choice between packed red cells and plasma, you're going to use the packed red cells when you have anaemia and the plasma when you have coagulopathy. So you may have a choice in terms of, of those products, depending on where, and what facilities you have available to you.

So if you take whole blood and you don't use it, you can store it in the fridge, but it's not the easiest of products to to do that with. You can store it for about 3 to 4 weeks. But it very quickly uses the activity of the, platelets from Vilovans factor and the factor 8.

So we don't tend to store whole fresh blood, and, and, well, it's not fresh if we store it, just whole blood. And we would try to separate that into the products that we can then use at a later stage if we want to. So we would then create fresh frozen plasma from the plasma bit and the packed red sauce, as you can see at the bottom, those two, products from that one transfusion that we have from that doughnut.

And red cells, essentially we spin down the blood that we've collected, and then we've got the red cells, we can at the bottom we've got the plasma at the top. We syphon off the plasma which then can be frozen, then we use that as fresh frozen plasma. And then the red cells are mixed with a lifespan extender, so it's called SAGM, so saline.

Adenosine glucose and manatol. The saline and saline and manatol are there to essentially to manage the similarity. The glucose and adenaline are energy sources for the red cells, so they're living cells, and we're gonna store them for a period of time before we use them.

And we can store them in the fridge for up to 6 weeks, so up to 42 days, so a bit longer than we can store just whole blood. There are some potential issues as we saw them, they, obviously there are living cells and there are changes that occur in the bag, but they're, they're good to use up until that length of time. We tend to try to use them a bit sooner, if we can, and in a busy practise they, they will get used in that regard.

But they're useful when we have anaemic patients, where we're wanting to give, red cells to patients where they're missing. So for example, anaemic patients or patients where we have, haemorrhage or, or blood loss, or red cell destruction, then all of those indications are gonna be helpful. And sometimes if we have a choice between whole fresh blood or patch red cells, if we're thinking about what what of those products would be better if we have a patient which is hypovolemic and we've got haemorrhage and we've lost a lot of whole blood, then whole fresh blood would be the best way forward.

But if we've got a patient with IMHA for. For example, where it's normal volemic, it's blood volume is essentially normal, but the proportion of red cells is reduced because those red cells have been destroyed, but the blood volume is the same, then giving pat red cells would be the better option because we're just replacing the bit that is missing in that regard. Now obviously we could give both of those products that wouldn't be a huge huge problem.

The only thing that we would potentially be a bit cautious of if we had a patient where we were concerned about the volume, for example, they had congestive heart failure or renal disease, then we might want to limit the volume we gave them, and in that regard, packed red cells would be the best way forward because we wouldn't be giving more volume than we absolutely needed to in that circumstance. The other half of the transfusion is the plasma bit, which is the, the liquid part rather than the cellular part. And obviously we've got all of the proteins within that liquid bit.

So all of the clotting factors, so including factor 5, factor 8, and, and 4vilivanse factor. And we can store that in the freezer, so, domestic freezer for up to a year at -30, and we use that for the treatment of all of the coagulation defects. After about a year, or if it's not frozen quickly enough, we've just got what we call frozen plasma.

And some of the transfusion factors, the clotting factors, are a little bit more labile than others. So factor 5 and factor 8, tend to be ones that deteriorate within plasma a little bit more quickly than, for example, the vitamin K dependent clotting factors. So factors 279, and 10, which are the ones that we need when we have redundant side toxicity.

And those are much more robust clotting factors. So after a year within the freeze in the freezer, fresh frozen plasma becomes what we call frozen plasma, because we can't guarantee quite so much active levels of factor 5, factor 8 and von Willevan's factor. But frozen plasma still has really good levels of factor 279 and 10, which are the ones we need for treating deny toxicity.

So we'll be able to, to get on top of those coagulopathies. And that bag of frozen plasma can stay within the freezer for up to 5 years. So within a 5 year period in practise, you're probably gonna see adenyx.

So just having a bag of frozen plasma within the practise to be able to use in those instances can be really useful. And frozen plasma, it's a little bit cheaper as well than than fresh frozen plasma. So if you only need those clotting factors for using re in treatment of redundancy toxicity, then, there's a little bit of a saving there as well in that regard.

And then we can do some fancy things, as I was alluding to, if we've got fresh resin and plasma, we can partly defrost it and spin it down to make more concentrated products, of things like, von Villevan's factor and factor, 8. So this is cryoprecipitate. It's got the same amount of von Willevan's factor and factor 8 in it as a bag of fresh frozen plasma, and actually, in fact, a bag of whole fresh blood.

It's just. That the volume is less. So, for example, if we had a Doberman that had all the disease that we're going to take to surgery, the volume of cryoprecipitate that we need to give is going to be much lower than giving bags of fresh frozen plasma breast of whole blood, and it wouldn't have all the other things that we didn't need, in it.

So it's a much more useful way of being able to do that. So, we're not gonna volume overlay that patient, and we've got that, product to be able to give in those circumstances where we have coagulopathies. So I was thinking about red cells and where we are with anaemic patients.

We've also started talking about where we are with coagulopathies and the plasma parts and the, the plasma proteins, the coagulation factors that we need to make the blood clot effectively. I just want to talk about, a different case. This is Hattie, she's a 4 year old female neutered Hamilton Stefari that.

Presented quite weak and she was having some really horrible hematomesis. So, essentially very bloody vomit, and some very bloody melemic faeces as well. So you can see that her bedding's a little bit stained with some of that vomit here.

And when we're examining her, she has ecchymoses around the jugular, very pale mucous membranes and, an increased heart rate. So she's lost red cells and, and blood volume as a result of that bleeding and haemorrhage. We can see that probably she's becoming transfusion dependent as a result of that with the pale mucous membranes and the increased heart rate.

When we think about coagulopathies and the blood not clotting effectively, we need to understand how blood does clot, and there are different stages to that. So we have primary hemostasis where we have the formulation of the platelet plug. We have stabilisation of that platelet plug with the formation of a fibrin meshwork and a clot around where those platelets are.

And then we have a breakdown of that fibriner clot and healing of that damaged area. So we need platelets on those platelets to be able to, to form the clot and be able to to constrict. We need formation of the fibrin meshwork, so secondary calculation, and then we need healing to occur afterwards.

And when those things go wrong, we see coagulopathies. We can see problems with that primary platelet plug forming. So either we don't have enough platelets or those platelets don't function effectively, and that tends to cause ecchymotic haemorrhages or petiation like this.

So on the, the lips here, we can see ecchymotic haemorrhage on the, the penis and on the eye. We've got little pinpoint, ecchymotic, petiation, and then in the groyne there, ecchymotic haemorrhage at the bottom. And those primary coagulation deficits happen when we don't have enough platelets, so thrombocytopenia.

So absolutely low numbers of of platelets, so we can't form a, a clot. All those platelets don't work properly. They don't, essentially adhere to areas where we've got damage, and we need von Willevan's factor for that to happen.

So von Willevan's factor would, deficiency would cause a problem with that. Or we see the problem with the platelets going from the normal, inert platelets that circulate in our blood all of the time to activated platelets that stick to things where they develop the pseudopods, as you can see the difference in these two pictures, the nice round ones at the top aren't doing anything. The ones at the bottom are all stuck together with the little pseudopods that are coming out to stick together, and we need those platelets to be able to activate.

And if they're not able to activate, for example, if we have a, a thrombocytopathia, there are some inherited ones, or we have renal disease or aspirin, for example, that we've given for, whatever reason to, to try and limit, co coagulation, then the platelets may not be able to do that effectively. So for primary coagulation, we need, platelet numbers, and we need those platelets to work properly, and we need a proviloance factor for that to happen. If we don't have those things, we may have a primary coagulation problem.

And then with circuitary coagulation defects, we tend to see that those bleeding, episodes are a little bit more significant. So we see large, either hemorrhagic incidences, so epistaxis, like from this dog's nose, or, in Hattie's case, she had a secondary haguropathy so really marked melena and hematomesis, or here we've got hemothorax, so we've got bleeding into the thoracic cavity which is causing a problem. So we can see that there's blood, that, that is around the lung within the, chest space that's causing an issue and a problem as a result of that.

And so co coagulation deficiencies are where we're not able to produce a fibrin meshwork to be able to stabilise that platelet plug. The second coagulation is, is, is complex and there are different models of that. Inherently we talk about the intrinsic and the extrinsic pathway, so, essentially contact and platelets, releasing clotting factors and activating clotting factors that allow us to get to the fibrin.

Or the intrinsic pathway where we've got release of tissue factor from damaged cells that again can activate the clotting pathways, and we'll get fibrin produced as the end point of that, coagulation pathway, so we can see that the clotting factors lead to that fibrin production, that stabilises the platelet clot, and then we get that area, healed essentially over that. And to measure whether we've got effective coagulation pathways, we can look at the ABTT and the PT and that gives us a good understanding of where fibrin is being produced. So those things will help us to understand where we have coagulation problems.

And there are a number of coagulation issues with secondary coagulation. We can have some inherited disorders, so haemophilia A and B, exactly the same as we have in in humans, where we've got factor 8 and factor 9 deficiency, or we can have acquired deficiencies as essentially those come where we're not able to produce clotting factors effectively, and usually that comes from vitamin K deficiencies. So either the liver isn't able to produce those properly, so we see them as severe, hepatic disease, or with crumembraced, hoddenicides, so essentially rat poisons that cause problems, which means that we can't produce enough of the clotting factors 27, 9 and 10 that cause a problem.

And that's exactly where we were with Hattie, that, she had had access to, rodenticide toxins. When she, owners got home, they found, some rat poison within the shed which she'd had access to, and that was what was causing a problem. So, when we did our investigations, we could see that she had normal numbers of platelets, and those platelets worked, in the sense that they were able to form, platelet clumps when we were looking at them under the microscope.

But when we were doing our clotting times, the times were very extended and the blood wouldn't clot effectively. So what we want to try and do when we've got rid of cy toxicity is to give vitamin K to enable the liver to produce more clotting factors. But in the immediacy to stop clotting, we're gonna need to give coagulation factors, and we do that by giving either frozen plasma or fresh frozen plasma to replace those clotting factors, and, and make sure that we've got, adequate numbers of those clotting factors, circulating.

She wasn't particularly anaemic here, so PCV of 22%, so we're not gonna transfuse with red cells at the moment, but it wouldn't be wrong to give whole fresh blood in this instance to be able to, to, to, to mitigate some of the loss in terms of the red cells and improve oxygen carrying capacity if we needed to as well. So lots of options potentially. It's just understanding which products we have available and the best way of being able to do that.

So when we're thinking about transfusions, we've obviously got two patients here that we're gonna want to transfuse to give red cells and to give coagulation factors to improve coagulopathies. And so how do we decide how much blood and how much plasma do we give in those instances? Well, we've got acute blood loss, we try and replace the volume as it's necessary, so often we give as much as we need to.

But if we've got a more planned situation, we can work out the volume of blood we might want to take from our donor to give to our patient, or what product we want to order from the blood bank to get us from where we are to where we want to be. And where we want to be is always a tricky one in the sense we want to utilise as much of the product as we have. So if we've got a bag of blood that we've got from the blood bank, we want to give as much of that as we can, so we're not wasting the product.

But sometimes that's tricky if we've got a really large dog, for example, and we've got a very low PCV, we might need to give multiple bags to be able to get back to a normal PCV and that may be cost prohibitive. So we're just taking a patient from managing with it it's not managing from its anaemia to a point where it can manage with the anaemia. So we may be taking it from PCV, for example, Tapa, which is 12 rather than.

Taking him back to a PTV of 40%, we might be taking him back to 25% or 30%, and he's gonna manage much better as a result of that, and then transfuse again as, as needed. So we don't always have to transfuse back to the point of normalcy with the, red cell numbers, but we will try and utilise as much of the product as we can wherever possible. So how do we work this out?

Well, if you're a vet school, you've probably seen these equations previously, which is the volume of blood to be transfused, equals the recipient weight times by the, percentage of red cells within the, blood, times by the desired PCV minus the current PCV divided by the PCV of the donor, and that will give you the volume of blood that we should transfuse to take the PCV from where it is to where we want it to be. It's a quite cumbersome equation, takes a little bit of time to work out where you put the numbers in and invariably doesn't quite give you the number that you want. So there's a nice study that shows that we can use some fudge factors, which is that 2 mL per kilo of whole fresh blood raises the PCV by 1%, and with pack cells, 1 mL per kilo, raises the PCV by 1%.

So, for example, in a 10 kg dog with a PCV of 10 that we want to get to 20%, that would be 200 mL of blood, if we're using whole blood. And then if we're using pack cells, that's just gonna be 100 mLs worth using 1 mL per kilo. So that 2 mL per kilo for whole fresh blood.

Raising the PCV by 1% and 1 mL per kilo, raising the PCVV by 1% for packed red cells works really and icy. And those fudge factors actually are a bit more accurate in terms of the outcome and the PCV from using that compared with where we were with that equation. So it makes it a little bit simpler when we work out what the effect we would want to have.

And then when we're thinking about plasma, we're thinking about a dose. So 10 to 20 mL per kilo is a dose, and we would give that, so it's a transfusion, and then see whether the clotting times stop, and then we'll repeat that dosing as is needed to make sure that we're getting to where we want to be, with understanding that the blood, is clotting in the way that we would want it to. So where does that blood come from?

Well, we need some donors. So when we're thinking about dogs, we need, dogs that are well behaved. We're usually looking for dogs over about 25 kg, we vaccinated, younger dogs, they're between 1 and 8, and not to have received transfusion previously.

They need to be well behaved, so they're sitting still for us to take the blood, and ideally, be of a universal blood donors. They're usually DA1 negative when we're talking about that. And then when we're using human blood bags, we would take a unit, so that's 450 mL of blood, which goes with the 63 mLs of CPDA that is in the blood bag to make sure that that blood clots, doesn't clot effectively in the tube and we've got the blood to be able to give.

And we want to recruit donors, to the pet blood bank and, just a, a, a little bit of a shout out if you have a patient, sorry, a dog that could be a donor. It's always a need for more donors, especially for negative donors, because negative blood will be the one that we need for transfusions. Dogs, usually enjoy.

Giving blood. I know my Labrador does, and having, a good resource and being able to have, donors available would be really important. So if you do have a dog that could potentially be, part of the wet blood bank, donor programme, then, please, have a look at that online, and, I'm sure they would be very grateful for your help.

Just mentioning cats a little bit, we do do blood transfusions in cats. At the moment we don't have the blood bank, as we said, and when we're giving blood taking blood transfusions from cats, obviously we do need them to be still. So sometimes that needs them to be sedated.

You know, cat marker used to be able to sit still for us to take blood for transfusion, but most cats will need a little bit of sedation, usually with, butylphenol dexamedatomagine just to be still enough for us to take the transfusion. And we're looking at taking 10 to 12 mL per kilo from the cat into to to the anticoagulated bag to to be able to, to give that as a transfusion product. Obviously blood types are really important, and we've mentioned this a little bit when we were talking about positive and negative blood.

And when we're talking about positive and negative blood, we're talking about DEA1. So DEA stands for dog erythrocyte antigen, and, and number 1 is the most important. And depending on the study, roughly half of the dogs in the population are positive and roughly half are negative.

It does vary a bit by breed and it does, by geographic location as well. But there are some other antigens as well, so you can see 3456, and there's a, a good number that have been identified and, and some other ones as well, so the dantigen, chi, things like that that are a little bit outside of the DEA antigen series. .

Most of the time we find that there aren't antibodies against those blood groups. So with positive and negative blood, when we're talking about DEA1, we don't see antibodies against that antigen, so it means that we can transfuse in the first instance without necessarily understanding where we are with, with the, blood type. That isn't advisable, and we always try to give negative blood to negative patients and positive blood to positive patients where we can, and if we don't know, then we would use negative blood in that instance so that we can make sure that there isn't likely to be a transfusion reaction.

Occasionally though, if we do know, we can still give a blood transfusion in the first instance because there shouldn't be antibodies against DA one on the surface of the cells. If we get that wrong though, we will start to see that that patient is sensitised and that could then cause transfusion reactions in the future, which may make few of the transfusions difficult. So this is, the, donor blood, which has got the antigen on the surface, and then this is the recipient blood which doesn't have that antigen on the surface.

And if we transfuse that donor blood that has the antigen on the surface into the patient, we will get sensitization. So those cells won't last as long as we would normally expect. Transfused blood probably lasts about sort of 30 to 45 days depending on, whether there's a destructive process that's present.

But when we transfuse them in that sort of circumstance, the body will realise that they're foreign and take them out of the circulation. But the next time we give that blood, we will risk there being an anaphylactic type reaction and therefore being transfusion problems as a result of that. So we need to be careful that we give that, blood in the first instance and we then don't give it again.

So positive blood to positive patients, negative blood to negative patients, and if we don't know, a negative donor would be the way forward. With cats, it's really important that we do understand their blood type because they do have antibodies against other blood groups. And it's a bit simpler in cats because they have lesser of the antigenic groups, so they have A and B, which are different proteins on the surface of the red cells, as the graphic on the screen sort of suggests.

Most bee cats have high levels of anti-A antibodies. So if we give A blood to BATs, almost invariably there'll be an anaphylactic reaction where those red cells are destroyed very rapidly and that can be very difficult for us to deal with. And a lot of ACATs have anti-B antibodies, so we always give A blood to AATs and B blood to BATs, and we make sure that we get that right, otherwise there can be transfusion reactions.

And there are another typing cards that we have both for dogs and for cats, and the blood bank will be able to supply both of those, so they're very easy to, to be able to, to get, and really nice to be able to see. And this is a transfusion card here, Lola and pumpkin. The A and the B are the test, strips, and then the C is just the control.

So for both Lola and pumpkin, they're both, blood group A. And so this would be a type compatible, transfusion, so we could give pumpkin and loadless blood in either combination, and these would be compatible in that respect. Cross matching is important, we don't tend to do that before our first transfusion, but it will be helpful once we've given a second transfusion because of the other blood groups that are available in in dogs, for example, we know we can type for DA1, but 347, for example, can be problematic as well.

So if we've given a transfusion, we may have sensitization against those other antigens. And after the first sort of 3 to 5 days, we will want to give a do a cross match to make sure that we're not seeing any antigen sensitization against those blood groups, that could potentially cause a problem. And similarly in cats, if we don't have typing available, it will tell us whether we've got compatible blood, and we would want to, to give a to do a cross match wherever possible before giving a transfusion, but obviously it takes a little bit of time to be able to do that.

And we can send the blood to the lab, and essentially what we're looking for in a cross match is that we don't have any antibodies within the patient that are gonna react to the red cells that we're giving and that would be our major cross match, that the recipient plasma doesn't contain antibodies that are gonna react against the donor red cells. And then a minor cross match where we've got the recipient red cells, and the donor plasma, so we haven't got any antibodies within the plasma that we're transfusing that can potentially cause a problem. So the lab will do this, they will wash the cells and then mix them back together with the, with the serum from the donor and the recipient to make sure that there aren't any reactions.

There are various ways that we can do this on the bench top where we can mix our cells together, where we can see that that's not causing a transfusion reaction, and then there are some gel strips that help us to look to see that the red cells aren't being, . clump together as a result of antigenic, antibody stimulation like this. And this would be an incompatible cross match where we have antibodies within the patient that are sensitised to the red cells that we were giving.

And if we've got clots like this and clumps of red cells within the patient, obviously, they're gonna get stuck in capillary bags, and that's gonna stop a lot of inflammation, and that's gonna be really problematic for our patient. Of course we should look under the microscope because we need to tell the difference if we have very fine stippling, whereas we have microscopic agglutination as we have on the right versus low formation, which is that stack of coins formation where we have all the red cells on top of each other. And this is the normal way that red cells move through the circulation through capillary beds and the blood is, is able to flow in a much more linear way as a result of that, whereas the microscopic agglutination on the other side is gonna be tricky, and again it's gonna sensitise that patient and potentially cause problems as a result of that.

So hopefully we have the blood type of the patient and we know that we've got the right donor type. How do we then take blood from our patient to be able to to then give it to our, our patient? Well, most of the time from our canine patients we'll do this conscious.

I use a little bit of like an an aesthetic, but we're gonna take the blood from the, jugular vein, clip and prep that area, in a surgical manner, and then usually we'll have the dog lying in lateral recumbency on the table. Sometimes people prefer to have the dog sitting up, so it doesn't really matter which way we do that. However, we can keep that dog still for the 3 to 5 minutes that it takes for us to potentially collect the blood in that, in that respect.

And then once we've got that area clipped and prepped, we will use the blood bag, and this is a human, blood bag where we've got the 63 mLs of CPDA aiming to collect 450 mLs of, blood, and 450 mL of blood roughly weighs 450 grammes. So we can weigh it on the scales, we'll tear the bag to start off with so we can see that it's at zero, and then as blood collects into the bag, we'll be able to tell that the weight goes up till we get to 450 grammes. And usually if we've got the dog on the table, we'll put the needle into the jugular.

And different people do it different ways, facing up, facing down, get slightly better flow if it faces up, so towards the, the flow towards the brain than if you flow flow down, but it doesn't matter too much, so it's the other way around in this picture. And then you have the bag below the level of the jugular, so, below the table or below the, the dog. And then rock the bag backwards and forwards and you can see that the blood is swirling into the bag as it's collected and you can see that it's mixing, and then you can weigh the bag to make sure that we're collecting the blood as we go forward.

And this is the dog just collecting the blood, he's very happy, you know, nice and still, try not to talk too much. My Labrador wags her tail constantly when we're taking blood from her, so you're very happy, which can be a bit tricky and distracting. But usually within that, 3 to 5 minutes, we'll be able to collect the blood that we need.

Got the blood bag to where we are, 450 mLs. At that point, we can sort of put some pressure over the jugular. We take the needle out, collect the blood into the blood bag, put a slight pressure bandage over the neck, which we remove after a few minutes, and, and the dog can have some biscuits, similar sort of, custard creams and a cup of tea as we would if we were given blood ourselves.

And then we can utilise that blood for our transfusion, which means we can then give it to our patient. Or if we've got the blood products from the blood bank, we can give our packed red cells, so we warn them if we take them out of the fridge. And fresh frozen plasma, we would defrost just in a warm water bath, at 37.5 degrees, takes about 20 minutes for that to happen, and then we can diffuse it, transfuse it into our patient.

Feline blood is a bit trickier because we don't have the right sized blood bag to be able to collect the blood in exactly the same way. So we're taking the blood into syringes, which we've pre-anticoagulated. So we've got 10 mL syringes or 20 mil syringes, with a 1 to 9 ratio of anticoagulant to blood.

So we would run the blood, the anticoagulant out of the blood bag into a sterile container and then draw up the anticoagulant into the syringe. So you've got 1 mL in that 10 mil syringe, or 2 mLs in that 20 mil syringe to be able to then take blood from the jugular from the cat. And usually we do that under a little bit of sedation, so a little bit of dexametatomidine and porphanil so that the cat is still.

And again, doing that from the jugular with the cat lying, usually on its back with the needle into the jugular, and then collecting the blood, into the syringe. And once we've collected the blood into the syringe, then we can then either put that into a giving set into a, into a bag so that we can then transfuse it via gravity or through a larger syringe, so we can use a syringe driver to be able to give that blood to our patient. So hopefully we've then collected the blood, so we've got our blood from our donor to be able to give to our patient, or we've got our blood product from the blood bank to be able to then transfuse that into our patient.

And this is where we need to then think about the transfusion rate and how we give that. And we always give transfusion products through a giving set, so they've got a philtre in, so they can, essentially philtre out any bits of debris or any small clots or, bits of material that we don't want to be there. And blood giving sets have slightly different drip rates, so these would be 15 drips per mL, whereas our normal fluid ones would be about 20 drips per mL.

So we needed to work that out when we're thinking about the rate. So this would be a transfusion set for the dog, and we can get the transfusion giving sets from the blood bank as well. There are paediatric ones for smaller bags as well, so we'd be able to order those when we ordered our blood products, er, which would be great.

And then we're thinking about cats, if we're giving them through a bag, we have the inline philtres like this, these are the Uha medical ones, which we've got the, 50 micron philtres. So we're pushing blood through a syringe so we can take that out, or the paediatric, are giving sets with the bags here, which again would philtre out bits of debris, which we like to, to just make sure that we're not causing any problems with clots that are, potentially present within the bag. When we're giving the transfusions, with dogs, we usually give them via gravity.

So we would have the blood bag hung up and we're giving the blood via gravity because most of the, infusion pumps that we have, essentially use mechanical, motion to move the fluid forward, and that mechanical motion can cause damage to red cells. They're very Few of those infusion pumps that are, are validated for use with the, with blood products and don't cause damage to, to, red cells by doing that. So with dog transfusions, we tend to do them by gravity, and there's some nice studies showing that the red cells have a longer longevity as a result of that, without the mechanical motion.

And movement, so gravity is the way forward. With cats, obviously it's a bit trickier because the volumes are less, so we give the blood, usually through a, a syringe and an infusion pump. So the syringe driver is pushing the blood forward.

Again, being careful to make sure that we mix the blood and make sure that it's suspended because we don't want the red cells to sediment out and just end up pushing the fluid and then ending up with a big clump of red cells at the end. So we just make sure we're rocking it backwards and forwards every 20 or 30 minutes to make sure that it's staying in suspension. But then an infusion, set will be really helpful to be able to make sure that we can get that into the patient in an accurate way.

So we've got our product, we've got our transfusion set, we've got our philtre. We then need to think about what rate we're going to give and what monitoring we're going to have to make sure we have to make sure we don't have any problems. So if we've got life threatening emergency and the patient is just bleeding really quickly, we just give the blood really quickly.

We replace what's being lost as quickly as we can. So sometimes in those situations we just get the blood hooked up and we just squeeze it in, because the patient is losing volume very quickly, we want to replace it very quickly. Hopefully they, that's not the standard situation, and that's the, the sort of, emergency point.

What we would want to try to do would be to give the bird in a much more controlled manner. And when we give it in a controlled manner, what we're doing is monitoring to make sure that there isn't a transfusion reaction. So we give it slowly to start off with for about the 1st 30 minutes, and usually we give it at a rate of 0.5 mL per kg per hour for that 1st 30 minute period.

And then we work out the rate to give the rest of the bag or the volume that we want to give over the next 3.5 hours. So our transfusion is given in a 4 hour period, which is the period we know that broaching the bag will keep sterility and make sure that the bag is able to be maintained.

It's also a period that is, relatively easy for the patient and, and with us in practise for, for monitoring in that regard, and for the patient to cope with the volume that we're giving if it's normal volemic, it shouldn't be overloaded as a result of that, if we're giving that sort of volume. So we give it for that 0. 0.5 mL per kg per hour for the 1st 30 minutes and then we increase the rate after that if everything is OK during that period.

Now during that period we're monitoring the patient very closely and we're monitoring for transfusion reactions and to do that we use a transfusion sheet, and these can be available from the Peppa Bank website as well, so you can download them, so you can use them. Very similar to an anaesthesia monitoring sheet and we're monitoring essentially for physiological problems, essentially looking to see that the heart rate is coming down as we're giving the red cells, as we're increasing the oxygen content. Should be seeing that respiratory rate and effort is coming down as well, and we're monitoring to make sure that the temperature is stable.

If we're seeing any sort of transfusion reaction, what we usually see is the heart rate spikes up, the temperature comes up, or the respiratory rate comes up as well, so it's a really nice way of being able to spot what's happening. And we'll do the temperature, every 30 minutes through the transfusion, and then the pulse and rests every 5. Minutes for that 30 minute period and then every 15 minutes thereafter and we can reduce the frequency if we're finding that the patient is stable as we're giving the transfusion.

So we're reducing the frequency that we're giving the the of doing the physiological monitoring as we're going through in that regard. So the transfusion sheet is very helpful. And the sorts of things that we're looking for are any sorts of transfusion reactions that could cause a problem, so things like volume overload, which would be that the patient is then starting to have respiratory rate and effort increase as a result of that, or that we have problems with acute, lung injury.

So we have respiratory changes that cause us to have inflammatory change within the lung. Or that the patient is just being unsettled or causing, problems, and the patient, most transfusion reactions are quite mild, so we see them perhaps in about 15 to 20% of patients. And most of the time that is that the patient is a little bit unsettled, maybe has a temperature that's come up a little bit or looks a little bit nauseous as a result of the transfusion.

And then we stop giving the transfusion and we can then restart the transfusion at a lower rate as a result of that. And usually that transfusion is fine for giving antiemetics or trying to, to deal with those transfusion reactions. Those really significant transfusion reactions where we have anaphylaxis are are really unlikely, but they usually start in a similar sort of manner.

So they usually start with the patient looking nauseous, starting to shiver, starting to tremor, and, and then they progress to the patient becoming recumbent, having, . Problems with, circulation and becoming, very shocked as a result of that. So it's important that we do recognise that happening.

And if there's any transfusion reaction that we're concerned about or worried about, then we stop giving the transfusion immediately and can consider what's happening. And at that point we may just give some antihistamines if the patient is nauseous, we may give some antiemetics, we may try to make that patient feel more comfortable. But then if that patient has settled, we can then restart the transfusion at the lower rate, so that induction rate of 0.5 mL per kg per hour to start off with and see whether it copes with a further transfusion.

Or if there's significant problems and that patient is developing anaphylaxis, then we can consider really aggressive treatments. So, considering steroids, considering adrenaline, both of those things aimed at essentially stabilising ma cells so there isn't further anaphylaxis, and then supporting the blood volume by giving fluids to really make sure that we're supporting things as, as. As we can and making sure that we're, supporting the blood volume as, as much as we can.

But those transfusion reactions are, are really uncommon, especially if we give our, get our typing and cross matching right. Most of the time those come from getting things wrong where we've given B blood to ACATs, for example, or not got things quite right. Or there's been some bacterial contamination in the back, and we're seeing, essentially, septic type reaction, to that hypersensitivity reaction to, to bacteria or white cells that lis as a result of that, but really uncommon for that to happen.

And then a couple of things just to mention before we finish off. We can do auto transfusion. So if we've got patients with really marked haemorrhage, we can take blood from a body cavity and give it back into the circulation.

So essentially we're taking blood from, the body cavity hemothorax or hemoabdomen and we're giving it back. This used to be something that we were cautious was if we had a ruptured spleen, for example, so we're worried about neoplastic seeding, but there's literature that suggests that. Isn't too much of a problem, so that can be something that we can do quite nicely.

The dog over here had a liver biopsy, and, bled as a result of that. And so we were able to take blood from the blood cavity and give it back into the vasculature alongside some pack cells, which is why we've got some darker blood here, which is the, the packed, cells of stool products alongside the, the blood that's come from the abdomen, whilst the surgeons got ready to go back in and, and understand why there was bleeding. And then if we do have cats that need transfusions and we don't have feline donors, then we can consider then a transfusion, and this would be a last resort because we would be giving dog blood to cats, essentially, so we'll be giving either blood from a donor or from a blood bank.

Huge amounts of, of discussion about whether this is the right thing to do, but it is effective and it would be something that we could do to essentially buy us some time for us to find a feline donor to be able to then transfuse with feline blood afterwards. The red cells don't last as long. Obviously, giving dog cells to a cat, the cat's gonna realise that they're foreign and destroy those cells quite quickly.

And usually that's within a 3 to 5 day window. And usually the cat will be quite, well as a result of that. So we will see essentially red cell destruction.

So there's free haemoglobin, jaundice as a result of that, and the cat feels pretty miserable for those 3 to 5 days. But if we've bought them the time. For us to do diagnostics, for example, if we're worried about neoplastic disease or FIP, it helps us to make decisions and also gives us time to, be able to then find a donor should we want to be able to transfuse things in the longer term.

So it is something that is a viable, suggestion when we have cats that we want to give transfusions to. So thank you very much for listening. We've covered a lot.

We've talked about why we give our blood, so for anemias and for our coagulopathies, and we've talked about the different products that we have available. We've talked about blood typing to make sure that we've got negative blood for negative dogs and positive blood for positive dogs, and we give a blood. ACATs and Blood to BCATs.

We've talked about how we would, cross match if we given previous transfusions. We've talked about giving blood through a philtre, and we've talked about giving it slowly to start off with a 0.5 mL per kg per hour and then increasing the rate so we get the whole of that transfusion in within that 4 hour window.

Making sure that we're monitoring closely, that we haven't got any transfusion reactions and physiologically, the temperature and heart rate is coming down during that 4 hour period. And that we're monitoring for any transfusion reactions that could potentially mean that we have a life threatening problem, although those are rare, and if we do see them, we want to stop and make sure that we're addressing those very, specifically. But please don't be afraid of, of, of giving transfusions, they, they make a massive difference to our patients.

If you want any advice about giving transfusions, then please contact the blood bank. They have a, advice service as well, which will be able to help you with any questions, so about how we do it or whether we should do it or not, but also some of the technicalities of the best ways of giving our transfusions. So thank you very much and I'm very happy to answer any questions.

Thank you again. Wow, I was frantically scribbling notes. I have gone through approximately 5 pages in my good notes notebook on my iPad.

So, I feel like I'm gonna have to go back through those again. We have a few questions. I know we are kind of fast approaching 9 p.m.

It is 8:59, but if you don't mind a couple. Questions, Simon, I'll try and pick out a few of these. So let's just see, I'm like trying to scroll back through.

So one question is, if we don't manage to get 450 mLs of blood from the donor, do you withdraw anticoagulant from the blood bag with the 1 to 9 ratio? Yes, so I, I guess that the two separate things. So one, if we've got a, if we want to take, less blood, so if we want to give maybe half a bag rather than a whole bag, then yes, we would run out half of the anticoagulants.

So you've still got that 1 to 9 ratio. The other thing would be if you're trying to take blood from a donor with the intention to get to 450 mL of blood, but you only get halfway through or or 3/4 of the way through that, then, whether you can still give that blood with the higher level of anticoagulant in it. Different people have different, effects of that, but usually if you've got more than halfway through, it would be reasonable to give that if you've got no other option, but you would need to be very carefully monitoring for hypokalemia, hypocalcemia as a result of that, cos you will get some calcium binding.

So, with the blood products from the blood bank, they're obviously very carefully controlled, but more practically when you're giving blood and then as long as you've got roughly half of the amount of blood within the blood bank, you'll probably be OK with transfusing it into the patient. Excellent, thank you. So I actually, there's a couple there's more popping in now, but I noticed too with a similar theme actually.

So one person is asking, is it a good idea to use methylprednisolone before transfusion in occasions to prevent anaphylaxis, and someone also asked the same thing regarding antihistamines. I believe it was chlorophyurramine that I saw. Yeah, so, so different things.

One, steroids are probably not gonna stop there being a transfusion reaction. So if you're using steroids because you need to to treat the underlying disease, for example, immune mediated disease, then just give, give the steroids that, that will be fine. You, you'll prevent red cell destruction from the immune mediated process, but you're not gonna stop there being a transfusion reaction.

The other question around antihistamines is whether they should be given before you give a transfusion or not. And again, there's slightly different schools of thought. Some people do suggest you give them, some people don't.

Personally, I don't tend to, because if there's a transfusion reaction, I like to see that as soon as possible and under understand what's happening, and then react to that if, if we know that that's there. There's possibly slightly more weight if we're using stored red cells that are slightly older, so in that sort of 4 to 6 week window, and then if we do see transfusion reaction, we'll often give antihistamines sooner as a result of that. But most of the time understanding what's happening and then reacting to it would be better rather than blunting the first part of a transfusion reaction and then missing something more significant later, so.

I think most people would suggest we don't give antihistamines, but it's not wrong to you, but I, I, I'd like to understand what's happening, as soon as it is possible, so we do not give antihistamines before we give transfusions. Excellent, thank you. Yeah, I've heard, I've heard, you know, people coming from both sides of that conversation.

I feel like what I have heard the most recently is what you were saying is, is ideally it's more of a reactive type situation than a preventative type situation. So it's interesting to hear you say that. Should we try and do one or two more?

I don't wanna, I was gonna say I don't wanna keep you too late. So one person, one person did ask why, was a whole blood transfusion not recommended for Hattie, that, in case you have that with the rodeocy toxicity, as the PCV was low along with deficient clotting factors. Yeah, I mean, it wouldn't, it wouldn't be wrong to do that.

So we, we gave fresh frozen plasma in that instance because, I forget where the exact, numbers were, but, she was coping from a red cell point of view. But if, if, you know, a piece of your 22%, it's kind of on the cusp, so it wouldn't be wrong to give a whole fresh blood transfusion, we had. Being in a, a big institute with an ICU you have the packed red cells and you have the, the plasma products available to you.

It's much harder then to go and find a blood donor to be able to do that usually involves me driving home to find my dog. So it's easier to give fresh phrase on plasma and then to deal with the anaemia with the packed red cells if we need to give them, but it would be absolutely reasonable to have given a, a whole blood transfusion in that regard. So it's, it's not wrong to you, which I, I think I said as, as we were talking through that, but that's not what we did in that instance.

So, yeah, it wouldn't, wouldn't be wrong to give a whole fresh blood transfusion. Yes, OK, so let's do one more, and I'm sorry if I didn't get to your questions. I will try and if I see any, I can try and come up with an easy way to maybe get some more answers for you guys from Simon, but one that just popped up that said, sorry, I got a bit confused with ventilation with anaemia.

So would you oxygenate anaemic patients that are just respiratory decompensating or distressed, or all anaemic patients until they could be transfused. So I think they're saying. They had a cat with a PCV of 5%, but it was very clinically bright and most it sounds like temp and respirations were within normal limits.

So checking if we need to be providing oxygen for those patients, which I think is not uncommon, particularly for our cats who walk in with a PCV of 3 and we're like, how are you still standing? I'm not sure how this is compatible with life. Yeah, no, it's it's always one of these miracles, isn't it?

They just suggest that that's a really adaptive process that the cats had some time to adapt to get to that level, so. It, it probably is in a a a a very fine balance because those numbers are not allowing us any leeway for there being a problem and giving oxygen would be a very reasonable thing to do as long as that's not stressing or unsettling the cat. So putting it in an oxygen cage rather than providing flow by, for example, would probably be a sensible way of approaching it.

I think probably what's caused confusion is where I've talked about ventilation and perfusion, and what I mean by that is the oxygenation bit and the, the oxygen content of the blood being the bit that's controlled by the respiratory and ventilatory bit, the cardiac output bit, the perfusion bit is the other side of that. If we can oxygenate anaemic patients, it will make it a, a bit of a difference, but we've probably got reasonable oxygenation just on room air in the high 90s. So if you can take that a little bit higher or to 100%, then that will increase oxygen content and improve oxygen delivery.

But making a difference with the transfusion is gonna be the bit that is really important bit. So, yes, oxygen will be helpful and probably isn't gonna cause any problems as long as it's not unsettling cats and causing it stress, but. We will still want to, to, to sort of improve that, oxygen content by transfusion and increasing the haemoglobin.

Excellent. Well, I think we could easily sit here for another hour answering people's questions, so I will cap it at that, and say thank you again, Simon, so much for being here to present this to us tonight. I, like I said, I have learned and remembered a lot.

There's another comment that just came up on here that said, thanks Simon. I've been a blood bank vet for 7 years and still learned a lot tonight. So I think there's always something to be said for refreshing or learning.

New things, so again we really appreciate you sharing all of your knowledge with us and thank you everyone again for joining us. I believe I saw a little note come up from Rebecca that said that there will be a link, a recording of this session and then CPD certificates will be available within 24 hours. Also just a quick note is that if you are interested in keeping up to date in more webinars and events that many is putting on, you can join our vet newsletter which I will also include in a post link.

I'm sure there's a fancy way that I can do that because we're always sending out more. We want to know what you guys want to see. We want to see you guys at events and so if you want to keep up with that, we do have a vet newsletter, and also our many nurses club on Facebook is also always sharing things.

So, thank you guys again for joining us.