Placenta Praevia
Anaesthesia for Placenta Praevia in a Jehovah’s Witness
You are the anaesthetic consultant on duty for the maternity services at your hospital (a tertiary referral multi disciplinary centre).
A 30-year-old pregnant (gravida 3 para 2) woman was admitted to the labour ward over night, with threatened pre-term labour. She is currently at 28 weeks gestation and required caesarian section for both deliveries in the past.
You have been asked to see her, as although the contractions have settled, a recent ultrasound is strongly suggestive of a placenta praevia.
The patient’s history documents that the patient is a Jehovah’s Witness.
What issues would you like to explore in this case?
This is a complicated case because we have a lady who is at high risk of blood loss and she’s a Jehovah’s Witness. The issues I’d like to explore are really around her pregnancy and whether there have been any other problems with the pregnancy, but the main issue to consider is what’s going to happen in the event of blood loss. And I’d like to know what her haemoglobin is initially, and I’d like to have a discussion around what products she would consider.
You said she has a high risk of blood loss. Why is that so?
Well she has had two previous caesarian sections and has placenta praevia according to the ultrasound. This increases the risk of blood loss because the placenta is attached to the uterus by the scar, so there’s a high chance the placenta won’t be removed intact and that can cause torrential bleeding.
If I told you that the placenta was posterior … Would that change what you said?
Well it means that if having a C section then the chance of going through the placenta with a scalpel is lower, because its on the posterior surface of the uterus but there’s still a chance it will be embedded into the uterus and be unable to be removed.
Do you know what that’s called?
That’s called increta and there may be percreta as well but we don’t know that.
So having had two previous c-sections, and I agree there is a chance of her having an acreta or a percreta, what do you think the risk of having an acreta or a percreta is in someone who has had two previous sections?
I’m not sure what the numbers are but the risk is moderate to high,
Do you want to have a guess about what the incidence would be?
Something like 10 to 20 percent.
And if you are concerned about this is there any imaging or approach available that could allay your fears or confirm your fears?
So, I would like to see an ultrasound.
If I told you that she had an anterior grade 3 praevia? What else would you like to know?
This means that it was anterior and very close to occluding the os so that having a vaginal birth would be very dangerous.
Does it help you in knowing if she’s got a percreta?
Not really, the ultrasound should be able to show us or define whether there is a percreta.
How sensitive or specific is an ultrasound? Do you have any idea?
If you get a positive ultrasound how good is that and if you get a negative ultrasound how good is that?
I’d presume it’s better at ruling it in than ruling it out. But I’m not sure.
Apart from ultrasound are you aware of any imaging modalities that can be used similarly to try to exclude or include a percreta?
She could have a CT scan but there is a high risk of radiation to the foetus. And I guess an MRI would be the other option.
If she were to have an acccreta, what do you need to think about in terms of your anaesthetic approach or your team approach?
You need a team approach obviously so discuss that with the patient and the obstetrician.
If she’s got an acccreta then a regional technique in my view is precluded and I think it would be better if possible to have a general anaesthetic. There needs to be blood available in the room and I would like to have invasive monitoring, because of the high chance of bleeding, so set up a level 1 and I’d get an extra set of hands available in case it went badly.
Are there any approaches you know which could minimise the chance or to hopefully prevent the chance of large blood loss if she does have an acreta?
Well the surgeons or the obstetricians can make an incision if possible above the level of the placenta if they know where it is and to reduce the bleeding of the percreta, ummm…
Do you know what the blood supply of an acccreta or the uterus is?
You’ve got the uterine arteries, there are a number of collateral arteries as well.
Where do the uterine arteries arise from?
Internal iliacs I think. So if you’re very worried about the bleeding you could clamp those arteries prophylactically.
Let’s move on now.
This lady you’ve seen with the threatened premature labour at 28 weeks, she’s now stopped labouring, she’s in the ward. What are the things you need to put in place given the fact you’ve seen her she’s 28 weeks and it may be a complicated birth?
So she needs a firm delivery plan, including obstetrics, obviously, pediatrics as well for the premature baby and discussion about whether she should have some steroids and a good anaesthetic plan surrounding what the technique would be for a C section. Also what products she would have if she did have a C section.
Lets move on to that because obviously being a Jehovah’s Witness this is an issue. How would you approach her given the fact that there is a concern she will have a large volume of blood loss?
Jehovah’s Witnesses often have a broad acceptance of various products so you need a detailed discussion detailing which products. In the hospital I work at we have a pro forma which lists all the products available and I can ask her and she can decide which one she will and won’t have. I would like to give her the opportunity to discuss with her church colleagues, I can’t remember the correct term, or with their family. I’d like to have this discussion alone.
What sort of products are on your pro forma?
Packed cells, but she’s unlikely to agree to those. The things that are generally controversial are clotting factors such as fresh frozen plasma, cryoprecipitate, albumin (which is not a clotting factor).
Whether they would be prepared to go onto bypass or would have haemo-dilution. Whether they would prefer to have a cell-saver although having a cell-saver is also controversial because it’s during pregnancy.
Well let’s talk about cell-saver you said that its controversial why is that and would you offer it to her?
Well it’s controversial because of the potential for amniotic fluid embolus, I think it comes down to a risk benefit analysis. In broad terms it’s probably not a good idea and depending on what other things she’d be prepared to have or do then I think it would be on the balance of risk.
Is there anything else you can to do someone who is a Jehovah’s Witness who may have bleeding?
You can increase the haemoglobin using erythropoetin which is usually acceptable because it’s recombinant. Iron supplements.
How long do those take?
They take a long time. Erythropoetin takes a few weeks and in most cases people would stop at 100 grams per litre, but I think with a pregnant patient at high risk of bleeding you can increase that to 120, with the risk being you can get increased thrombosis with high EPO levels. Iron takes a red cell turnover so at least a couple of months.