Episode 161 Blood Transfusion

Are you already familiar with the life-saving role of blood transfusions in obstetrics? If not, get ready for an enlightening journey into this critical aspect of maternity care. This episode is packed with insights about the ins and outs of transfusions, from packed red cells to platelets, plus everything else a woman might need to replace following excessive bleeding during pregnancy or childbirth. We also introduce you to the role of a hematologist and a game-changing device called TEG. 

Pregnancy and childbirth can sometimes bring along unforeseen complications. Here, we delve into potential reactions during transfusions, the significance of monitoring and consent, and the intricacies of platelet transfusions. We also discuss the importance of knowing a woman's blood group and the use of O negative blood in emergencies. Wrapping up, we extend an invite to engage more with the topic and seek your support to keep the ObsPod alive and kicking. Tune in and immerse yourself in the world of obstetrics!

Want to know more?
https://www.rcog.org.uk/guidance/browse-all-guidance/green-top-guidelines/blood-transfusions-in-obstetrics-green-top-guideline-no-47/
https://nhsbtdbe.blob.core.windows.net/umbraco-assets-corp/23998/inf1580-1-receiving-a-blood-transfusion-print-friendly.pdf
https://www.nhs.uk/conditions/blood-transfusion/
https://epostersonline.com/oaa2022/poster/p9?view=true
Willing to donate blood in the uk?
https://www.nhsbt.nhs.uk/

Thank you all for listening, My name is Florence Wilcock I am an NHS doctor working as an obstetrician, specialising in the care of both mother and baby during pregnancy and birth. If you have enjoyed my podcast please do continue to subscribe, rate, review and recommend my podcast on your podcast provider.
If you have found my ideas helpful whilst expecting your baby or working in maternity care please spread the word & help theobspod reach other parents or staff who may be interested in exploring all things pregnancy and birth.
Keeping my podcast running without ads or sponsorship is important to me. I want to keep it free and accessible to all but it costs me a small amount each month to maintain and keep the episodes live, if you wish to contribute anything to support theobspod please head over to my buy me a coffee page https://bmc.link/theobspodV any donation very gratefully received however small.
Its easy to explore my back catalogue of episodes here https://padlet.com/WhoseShoes/TheObsPod I have a wide range of topics that may help you make decisions for yourself and your baby during pregnancy as well as some more reflective episodes on life as a doctor.
If you want to get in touch to suggest topics, I love to hear your thoughts and ideas. You can find out more about me on Twitter @FWmaternity & @TheObsPod as well as Instagram @TheObsPod and e...

Transcript

Speaker 1: 0:00

Hello, my name is Florence. Welcome to the ObsPod. I'm an NHS obstetrician hoping to share some thoughts and experiences about my working life. Perhaps you enjoy Call the Midwife. Maybe birth fascinates you, or you're simply curious about what exactly an obstetrician is. You might be pregnant and preparing for birth. Perhaps you work in maternity and want to know what makes your obstetric colleagues tick, or you want some fresh ideas and inspiration. Whichever of these is the case and, for that matter, anyone else that's interested, the ObsPod is for you.

Speaker 1: 0:49

Episode 161 Blood Transfusion. It might seem odd to pick the topic of blood transfusion. Not many women will need a blood transfusion, but for some women, in some situations which may or may not be anticipated, a blood transfusion at some point during their maternity care may be absolutely essential and life-saving. I have previously touched on this in episode 41, blood Loss, so you may like to go back and listen to that to understand a bit of context about why a woman might need a blood transfusion. But today I'm going to focus a bit on blood transfusion itself. What do we mean by a blood transfusion and also why? One of the questions we'll ask at the beginning of pregnancy is would you accept a blood transfusion? Because for some women, a blood transfusion will be unacceptable and given that, I've just said, a blood transfusion can be life-saving, these women need particular care and planning during their pregnancy to make sure they have a safe outcome.

Speaker 1: 2:17

Often, what we refer to as a blood transfusion is packed red cells, the cells that carry the oxygen around the blood. That's what we most commonly use, but this isn't actually blood. As I've just mentioned, it's packed red cells, so it's a component of the blood, and actually quite a lot of other components of the blood are removed. When a woman is bleeding, she's not just losing her packed red cells, she's losing all her blood. So that's red blood cells, white blood cells, platelets the little cells that clot the blood and plasma, and within the plasma are all sorts of important proteins such as clotting factors. So, depending on what the reason is that a woman needs a blood transfusion and whether she's actively bleeding, at that point in time we may need to replace more than just the red blood cells that we casually refer to as blood. We may need to add in other blood products, other elements of the blood that have been removed from those packed red cells.

Speaker 1: 3:49

The commonest situation in which we may need to give blood in obstetrics is because of excessive bleeding after the birth of the baby, excessive blood loss, and the reasons for that I've talked about back in episode 41, so I'm not going to go into them here. But a woman can bleed very fast, particularly if she's bleeding from the placental bed, where the placenta has been attached to the wall of the womb. And if a woman is unstable so she's putting up her heart rate and dropping her blood pressure and she's got ongoing bleeding, we will need to think about a blood transfusion on the basis of her hemodynamics. That's how her body is responding to that loss of blood volume. An adult on average, of average size, will have about seven litres of blood. If a woman is losing perhaps two litres or more, that's a significant proportion of her whole circulating blood volume. And therefore, although we may replace that with fluid so water, with salts in such as heartmans or saline, that increases the volume but it doesn't increase the blood cells that help carry oxygen and it doesn't replace the proteins that I just mentioned or the platelets that are needed to help clot the blood. So in an active bleeding situation where large amounts of blood loss are occurring, we will be much more likely to give not only packed red blood cells but also possibly platelets and something called FFP fresh frozen plasma, which contains all the proteins the clotting factors that I mentioned that are essential in part of our treatment to help stop bleeding.

Speaker 1: 6:21

So when an active bleeding situation is happening, one of the key people we need to contact is the hematologist, the blood specialist, who can work with the lab, look at the clotting results and tell us exactly what we need to give to not only replace the red blood cells that are carrying oxygen, but also replace the other components of the blood that are needed to maintain normal clotting levels. These days we also have access to a new device, so-called TEG, which stands for Thrombo-Elastography System, and that is a little point of care test. So that is a test where the anesthetist can take some blood in the operating theatre and, within about 10 minutes, get a little graph of what's happening within the clotting cascade and how clot is or isn't forming. It gives a little picture that looks like a wine glass on its side, and from this we can work out which elements of the clotting cascade aren't working and therefore what bits of the clotting cascade we might need to replace. This would seem obviously beneficial but reviewing some documents to record this episode, there isn't yet clear evidence that it improves outcomes. But it gives us a clear and quick picture in real time in the operating theatre which we can then respond to.

Speaker 1: 8:27

The other situation in which we may use a blood transfusion may be after excessive bleeding. The bleeding has settled, the woman is relatively stable, but she's significantly dropped her blood count. She may be feeling extremely dizzy, exhausted, drained. We may look at her on the wall, drowned, and notice that she's very pale and we may recommend a blood transfusion because while she will produce her own blood cells, to eventually top herself up that could take weeks. So we work on what her blood count is. We'd expect a woman to have a hemoglobin that's the oxygen carrying protein in the red blood cell of hopefully above 110 grams per litre at the end of pregnancy, and women can tolerate significantly lower blood counts. But if acutely a woman's blood count drops below 80 grams per litre, she's likely to be very symptomatic breathless, exhausted, high pulse and really struggling. And that's usually the level at which we think about blood transfusion. If it's above 80 or 90, then often iron tablets and a bit of time will be sufficient In these situations, a woman has much more choice about whether she has a transfusion, and we will usually give her a very nice information leaflet, produced by the NHS Blood Transfusion Service, that explains exactly what having a blood transfusion involves, what the point of it is, what it will feel like and what risks there are.

Speaker 1: 10:42

And yes, blood transfusion is not without risk. I think the thing people worry about is mainly infection, and actually, if you look at the information leaflet, the risk of infection is unbelievably low because blood transfusions blood that is given is all tested, so the chance of getting hepatitis B, hiv is less than one in a million, and then less than one in 10 million. What is much more likely to be an issue is a reaction to a blood transfusion, and that's because it's incredibly important that the blood is matched up to the person, so it needs to be the correct blood group and we need to be sure that the person receiving the blood transfusion doesn't have any unusual antibodies. So actually, the risks related to blood transfusion are more to do with incorrectly identifying the patient. When we take a sample for what we call group and save, we're ascending the patient's blood off to the lab to be matched up. It's absolutely essential that we are sending the correct sample, it hasn't got muddled up with anyone else's sample, we've written all the correct patient identifying information on the bottle and on the request form and that we check the identification name band of the patient before we give the blood and the blood is correctly matched. So sometimes it drives us totally mad in an emergency situation when we send something off to the lab and the lab say we've spelt something wrong, the patient name doesn't match or they can't read the writing. But actually they're doing that with good cause. And the reason I say it drives us mad is we have to retake the sample, have to rewrite it. And you might think in this day and age, why are we writing? Why isn't it all automated? Well, the reason is that for all our other blood tests it is automated. We can print a sticker and slap it on the tube of blood. But actually that could be prone to far more errors than us writing and correctly identifying the sample because it's so easy to put a sticker on the wrong tube. So the risks of blood transfusion are small, but are our responsibility as clinicians when we're taking those group and save or cross match samples Most people will not have a reaction to blood, but some people will.

Speaker 1: 14:01

And you may feel when you're having a blood transfusion is if you've got a slight temperature, feel a bit flushed, and that can be due to a mild immune reaction. And this means that while someone is having a blood transfusion, we'll be doing regular observations pulse, blood pressure, temperature and making sure that they're not having a reaction. And if you are having a reaction, we have to stop the blood transfusion immediately, send it back to the lab to see what's happened. Reactions are very carefully monitored and then of course, we'll be giving paracetamol or maybe some anti-histamines, and it depends what the reaction is. So if a woman is being offered a blood transfusion in not an emergency situation, we'll give her this information leaflet so that she can decide, just like anything else, whether she gives us her consent to have that blood transfusion.

Speaker 1: 15:05

Rarely, we might use a blood transfusion in the anti-natal period if we've got women that are getting very anemic. Their iron levels are low, perhaps they haven't responded to iron treatment or maybe they have a condition that means that they can't actually have iron treatment and therefore we might give them an anti-natal blood transfusion, top them up prior to giving birth to try and get them in good shape for birth and so that they're at a safe level in case they should have that unexpected excessive blood loss after the baby's born. Some women will have lower than average platelets the cells that clot the blood during pregnancy and I've talked previously about this in episode 107, so you can find out a bit more there. It's unusual for us to give a platelet transfusion, but if a woman's platelets have dropped very low, either because of pregnancy or because she has another condition separate from pregnancy that means her platelets are very low, then we may prepare and plan and give her a platelet transfusion around the time of birth.

Speaker 1: 16:35

Platelets don't last very long in the bloodstream. A red blood cell lasts approximately 120 days. Platelets actually drop off within about 72 hours of when the transfusion was given. Coming back down to the previous platelet count. So for women with very low platelets usually at a level of 50 or lower is when we're thinking about giving platelet transfusion. We will give that platelet transfusion maybe immediately prior to performing an intervention such as a plan cesarean birth, immediately before and then during and then immediately after, depending on how many pools of platelets we're going to give.

Speaker 1: 17:35

So the timing of giving platelets needs much more fine-tuning and platelets aren't always necessarily available in every hospital all the time. So many of us will work in a hospital where we have a laboratory which will provide blood and match us up blood, but we won't necessarily have access to all the blood products. They may need to come from a regional transfusion centre. So certainly in my hospital if we need an excessive amount of platelets or very specific, more rare blood group types, we will need to get blood sent over from our local regional transfusion centre. So this needs a bit more planning and if we're in an emergency situation, obviously we don't have the ability to do that. But if we have a more planned situation, like a planned cesarean birth or a planned induction of labour, then matching up and getting ready from our regional transfusion lab the blood products that we think a woman might need is really critical and sometimes if we absolutely have to and we haven't got this ready, we will decide it's not safe to go ahead and we may postpone things until such time as we can get the right blood products in the right place. Many years ago this was actually a stipulation for an obstetric unit that you had a working lab with access to blood products because, like I said, blood loss can be of such an unpredictable nature in maternity care. So I mentioned there a little bit about matching and getting blood ready.

Speaker 1: 19:45

Most of the blood we give the red cells that I mentioned are what we call fully cross-matched blood. We will have a record of the woman's blood group and type. But we will take a sample at that point when a blood transfusion is necessary. We'll send it to the lab and they'll match it up and they'll give her red cells from a donor that is compatible with her group. They fully matched up and that gives her the least chance of a reaction to the blood transfusion. If we've got a little bit less time we're in a bit more of an emergency situation we might give group specific blood. So the full cross-matched blood takes usually around an hour and a woman can lose a lot of blood in that time. But if she's stable and we're on top of it, we can wait for that fully cross-matched blood. If actually things are a bit more unstable and we haven't got that time, we have on record that woman's blood group and they can give us what's called group specific blood a bit faster. So they've matched it up. They know it's compatible with the blood group we have on record for her and that she didn't have any antibodies at that time, and they can give us the relevant blood group group specific blood a bit quicker In a dire emergency. Maybe we don't have this woman's blood group on record, maybe she wasn't booked for antenatal care with us or she's literally just come in off the street, or it's a dire emergency. She's losing blood so fast that we just simply do not have time for that matching process.

Speaker 1: 21:50

We will give O negative blood, what's known as the universal donor. It should be compatible with everybody, unless there are antibodies we don't know about. So it's termed the universal donor and this is what we give in extreme situations. Because there's some ready in the lab, it can literally be issued and in our case in my hospital, we can literally send someone over and within five, 10 minutes we can have the O negative blood in the operating theater. So this is the reason why we take blood group as part of the booking blood tests at the start of pregnancy and then again at 28 weeks. We're checking the woman's blood group, but we're also checking for the development of any antibodies, things that may make giving a blood transfusion more challenging, so that we know, if there is that unexpected emergency situation, what's the best thing that we can do.

Speaker 1: 23:01

At the beginning of the episode I mentioned that we will ask women at that first booking appointment whether they're willing to have blood products. What do we do if they say no? The commonest reason I've come across to say no is if the woman is a member of the Jehovah's Witnesses. Jehovah's Witnesses have a religious objection to being given blood and blood products. We have a responsibility. If a woman says she doesn't want to have blood products and would decline them even in a life-threatening situation, we have a responsibility to explore this thoroughly and tenately. Most trusts will have some guidance and an advanced directive that women can sign. We can go through with them. All the different components of blood remember we've talked about red blood cells, platelets, fresh frozen plasma and there are some other alternatives that may or may not be helpful in an extreme situation. There's a green top guideline on this and I've put it in the show notes so you can have a little browse.

Speaker 1: 24:33

One of the key things alongside having these very detailed conversations about what a woman will or won't accept, is to consider what is her individualised chance of having excessive bleeding. If she's got an otherwise uncomplicated pregnancy, there's a relatively low chance. You'll go through things in detail with her but hopefully what will happen is she will have a chance to have excessive bleeding. You can do things during pregnancy, such as iron supplementation, to make sure that she's in good shape when she's coming up to the time of birth, that her hemoglobin is at a good level, that she's not anemic and she's doing well. Then, if something does happen and she has excessive blood loss, she's starting off in the best possible physical shape.

Speaker 1: 25:40

But some women who don't want to have blood products in any situation will have a major chance of bleeding. For example, over the years I've cared for women who are Jehovah's Witnesses, who have large fibroids that may make them very difficult and increase the risk of bleeding, regardless of whether they have intervention or not, and also women with placenta previa, a low-lying placenta, which is a major risk factor for excessive blood loss. These women we need to think very carefully about where they give birth. Some hospitals will have access to cell salvage, that is, as a woman is bleeding, the blood can be collected in the operating theatre, washed, processed and returned back into the woman's body. It isn't a trivial procedure. It's a very important procedure and also staff to have the technical expertise to work that machinery. Not all maternity units have this available and again, it's personal because not everyone will accept this either.

Speaker 1: 27:15

But for some Jehovah's Witnesses cell salvage is an acceptable option and if you're caring for a woman who has a high chance of excessive bleeding around the time of birth, then it is our responsibility to explain to them what is or isn't available at the maternity unit they've chosen to book at. In some situations I have advised women actually it would be better for you to have your baby at this neighboring hospital that has the ability for cell salvage. It would be safer. Perhaps you're not going to need anything, perhaps excessive bleeding is not going to occur, but given the fact you have a higher chance, it would be prudent for you to transfer care there and I will help them make the necessary arrangements. Again, of course, it's their choice. They may not wish to move and I have in some situations been involved in major obstetric hemorrhage, hugely excessive blood loss in a number of women who absolutely did not want to have a blood transfusion under any circumstances, and therefore I've witnessed firsthand the impact this can have on the patient dropping a blood count to levels almost incompatible with life and the extremely debilitating recovery, intensive care, admissions, separation from baby and very long journey to health that this can sometimes entail.

Speaker 1: 29:20

It is difficult for us as professionals sometimes to relate to these choices, but, as with everything in maternity care, there is a choice. We may not understand or appreciate the choice a woman is making, but all we can do is give her information. So if at the beginning of pregnancy, a woman says to us she absolutely, under no circumstances, would accept blood products or blood transfusion, then it's absolutely essential early on in the pregnancy for her to see an obstetrician, possibly an anesthetist too, and have very detailed, extensive conversations, give her time to think about it, give her the relevant advanced directive to look at, come back to another appointment, sign it, discuss it and have it very thoroughly thought through so that in the advent of a situation where bleeding may become likely, we know exactly what we're doing and we'll be much more preemptive giving other drugs and medication earlier, perhaps at a lower threshold, to try and prevent bleeding in those situations and go above and beyond with all the other things we have up our sleeve to deal with excessive bleeding, to try and make things as safe as possible, given the context of her decision. What's my zesty bit? I think there are a couple of aspects of my zesty bit the importance of blood being potentially a life-preserving intervention, understanding when we're talking about blood we need to be a bit more accurate about exactly what blood product we're talking about, and being aware of the importance of being aware that women who do not want to have blood products under any circumstance need very careful thought and preparation. But the other aspect of it is there is a massive shortage of blood. There's a national shortage of blood products, particularly rare blood groups that have some associations with some of our ethnic minority population, and therefore we have a responsibility as clinicians using blood to also try and encourage people to donate blood.

Speaker 1: 32:33

I used to be a blood donor when I was young, when I was younger, and then I stopped after a period of time when I had my own children. Recently, one of my relatives needed an emergency blood transfusion and it got me thinking I really ought to sign up again. So I have. So I guess the other aspect of my zesty bit is to encourage you. If you can't give blood yourself, encourage friends, colleagues, relatives, other people that can to give this very, very precious commodity. Go on the National Blood Transfusion website, which I've put in the show notes, and you never know, that precious pint you give might help a new mum in a time of crisis. Thanks for listening.

Speaker 1: 33:46

I very much hope you found this episode of the OBS pod interesting. If you have, it'd be fantastic If you could subscribe, rate and review, on whatever platform you find, your podcasts, as well as recommending the OBS pod to anyone you think might find it interesting. There's also tons of episodes to explore in my back catalog from clinical topics, my career and journey as an obstetrician and life in the NHS more generally. I'd like to assure women I care for that. I take confidentiality very seriously and take great care not to use any patient identifiable information unless I have expressly asked the permission of the person involved on that rare occasion when it's been absolutely necessary.

Speaker 1: 34:43

If you found this episode interesting and want to explore the subject a little more deeply, don't forget to take a look at the programme notes where I've attached some links. If you want to get in touch to suggest topics for future episodes, you can find me at the OBS pod on Twitter and Instagram and you can email me theobspod at gmailcom. Finally, it's very important to me to keep the OBS pod free and accessible to as many people as possible, but it does cost me a very small amount to keep it going and keep it live on the internet. So if you've enjoyed my episodes and, by chance, you do have a tiny bit to spare, you can now contribute to keep the podcast going and keep it free via my link to buy me a coffee. Don't feel under any obligation, but if you'd like to contribute, you can do it. Thank you for listening.