Slides
Transcript
Good afternoon. If you forgive me, I’m going to start with an anecdote. I came to give you an obstetric anesthesiologist perspective and I thought it might be somewhat relevant. But I had the opportunity to meet a young woman outside just at lunch and she told me the story of having a labor epidural anesthetic and then ending up in the office of several of you. So I think it is quite relevant, and I’ll tell you my perspective.
So first of all, we in obstetric anesthesia prevent pain. When someone gets a PDPH, it’s devastating both for the patient and for us. We’re interventionalists by nature. We do think about medication in terms of therapies, but ultimately we like to do things with our hands. And although we’re really dedicated to the scientific method, the data for us is not very good. It’s low quality.
Here’s the other thing. Neuraxial anesthesia is really where it’s at. So if you’re talking about labor pain management, there are lots of other things you can do. Some of them even have some satisfaction. But in terms of pain relief, it’s spinal and epidural and combinations thereof that really give you pain management. And when you’re talking about cesarean delivery, a well-placed neuraxial anesthetic by far is the safest for mother and baby.
But the problem is no matter what we do—and they have tried to make fancy syringes and we use neuraxial ultrasound now, which is particularly good for learners—no matter what we do, particularly in the epidural procedure, there is about a 1% chance of getting inadvertent dural puncture, and then about half of those patients get a spinal epidural headache, PDPH. We’re learning more and more that some of those patients have chronic sequelae from them. It’s a clinical diagnosis for us and hopefully we look at the diagnostic criteria that we should. But I’ll tell you a couple of things.
First of all, we like to have a lot of denial. So certainly if we haven’t seen the dural puncture and we haven’t seen the CSF, we think that neck stiffness—and it almost always does present with neck stiffness in this population—is because she was pushing and she was in all kinds of strange and tense situations when she was pushing. But I will tell you a secret, which is that despite the gymnastics that we go through when we deliver a baby, most women do not complain of neck stiffness after delivering. It’s those with PDPH that do.
And the postural aspect—for a long time we were taught that every woman with a PDPH from obstetrics had an orthostatic headache. And the reality is we all know they don’t all. There are red flag symptoms that cause us to think of other things, and we’ll talk about those other things in a minute, and they are the things for you who are neurologists and neurosurgeons that we should be thinking of. So certainly if the headache is one thing and then acutely becomes something else—altered level of consciousness, seizures, focal or lateralizing neurologic deficits—those are the times when we call our neurologic or neurosurgical colleagues, and we do see other things.
So when we do call our neurological colleagues, they often look for venous sinus thrombosis. And of the non-infectious etiologies, although it’s a rare entity overall, postpartum women are at incredibly high risk. There’s sort of a perfect setup for this entity with stasis, vascular damage, and hypercoagulability, and they get stroke.
These young women are at increased risk for postpartum stroke, particularly in the postpartum area, and the differential diagnosis is long. This is just a list of the differential diagnosis of headache, but up to 40% of postpartum patients get headache, and whereas most of them are primary headaches—migraine, tension headaches—we have seen, I myself have seen, despite the fact that my career is long, have seen women with every single one of these causes of headaches, of these secondary causes of headaches, and making sure we don’t miss them is important.
So we were traditionally taught, and I have myself written papers on the fact, that this is a classic CSF leak with brain sagging, traction on the bridging veins, some compensatory cerebrovasodilation. More recently, we have gotten interested in the trigeminovascular system as well, and when we talk about therapies and such, we’ll talk about those.
We don’t image most of the people. This is a group that did image a group of 40 or so patients—postpartum patients within about 48 to 72 hours—who had PDPH. They did see the classic meningeal enhancement. Interestingly, none of these patients had brain sagging, which for us was a surprising finding, maybe not so much for you.
Recently, a number of the anesthetic subspecialty professional organizations, as well as some other organizations, got together and said we have been doing such a broad number of things related to PDPH, and we think we know the risk factors, but we at least have to do a reasonable systematic review of the literature. We did, and we did rating and grading of the evidence to try to see what we had.
And we went through a Delphi process and such to figure out what was going on. And I don’t think any of this will be a surprise to you, but I will survey and summarize some of the issues. The things that did have high correlation for risk factors were age and sex and a history of headache, and interestingly smoking decreased the risk. And for age it was very young age and then the age of childbearing. So certainly for us in obstetric anesthesiology, we are the group who get our patients who get PDPH if they get an inadvertent dural puncture, and depending on what kind of needles we use.
And talking about needles, and this is probably a good group to talk about needles to. Needle is the number one modifiable risk factor. So it was very interesting as you’re talking about myelograms and other tests, what needles are you using? So it turns out, and I hope during the Q&A you will actually tell me what needles you are using, particularly on your young and young and female patients. So it turns out there is of course an interaction between the type of needle, the size, and if it is not a pencil point needle, some other factors which we’ll talk about in a minute. 8 of 10 studies comparing cutting needles of different sizes found a reduction as you go with the higher gauge or more narrow needles.
This image is the difference between when you have to the left of the screen a pencil point needle where the tip is specially engineered and a cutting needle to the right. And these are the differences between the holes they make. This is a 25 gauge needle in both cases, so very narrow gauge. And we might think that the nice clean cut of a cutting needle would heal better, but it turns out that the more craggy cut is the one that heals much better, presumably, because it’s less likely to get a headache.
There are two meta-analyses at least, and this is one of them that came out in The Lancet that says that these atraumatic needles, the one that has the specially engineered tip, decrease the risk of post-dural puncture headache. Something to think about. And that’s even if you have to use a larger gauge. So there’s a gentleman outside with a spinal kit and an LP kit, excuse me. And I said to him, “What size needle are people asking for in their LP kits and what kinds of tips?” So he said, “Well, some people,” and I was actually—I had a rare proud moment to be from the United States these days, and I do have to say it is a rare proud moment when he said that in the United States, neurologists were more and more asking for 22 gauge with pencil point tips for their lumbar puncture kits, but that overall people still were using cutting needles. And many of these people do get PDPHs.
It’s when you use a cutting needle that some of these other things start to matter. And they are things like having the bevel parallel to the spine, decreasing the number of attempts, which probably is highly correlated to having a more experienced operator, and the patient being in lateral decubitus position, which is probably what you do anyway. Of all the preventative measures that we tried to use, and there are many, I’ll just say a few words.
In terms of the non-pharmacological things, bed rest, fluid therapy, the abdominal binders that we talked about, this was a group that was trying to make high quality recommendations. None of these could they make high-level recommendations, not surprisingly. And actually, bed rest in a postpartum patient is a) not very feasible given that they have a new baby and b) not a good idea because they are pro-thrombotic, and you don’t want them to get a DVT or worse, a PE.
The pharmacologic measures, most of them again, the preponderance of evidence does not say that they really make a difference ultimately in the outcome. Cosyntropin, there’s a little bit of evidence to suggest, and a pediatric study to suggest. What we use in the United States is usually NSAIDs, Tylenol, and some people use the triptans although they’re afraid of breastfeeding. The reality is that there’s no evidence that it’s a problem with breastfeeding, and I think there’s a real overuse of Fioricet. I say overuse because our neurology colleagues, when they use Fioricet, will tell the patients that they should not use more than a few a month. Whereas you’ll find the anesthesiologist giving a patient a bottle of Fioricet and saying take them like you would an antibiotic every four to six hours.
We learned early on about blood patches, and remember we’re doing blind blood patches, and we’ll talk about that more in a minute. The blood stays in the epidural space less than 3 hours, fewer than 3 hours. By 3 hours it’s already in the subcutaneous tissue, and what’s left are some fibrin clots. So we always imagine those clots hopefully making a scab on the hole that we have made.
And some things about our blood patches. We are relatively assertive—I won’t say aggressive, but assertive—about doing blood patches. Again, our women are young and healthy and want to get up and tend to their babies. Because this neck stiffness, this meningeal—let’s call it irritation, or perhaps that’s not physiologically correct—but this feeling of stiffness, even lying down, they often have trouble with breastfeeding if that’s what they’ve chosen to do.
We often want to patch them as soon as they are severely symptomatic after trying some of these conservative therapies. We will discuss a couple of other therapies that are procedural in a moment. The optimal volume of blood is not known. I am fascinated with the large volumes of blood that you’re able to put in, and I am assuming from listening to all of your lectures that that’s because chronically you have these collections of CSF which distend the epidural space.
We’ve tried to do multi-center trials where centers put 10, 20, or 30 mls of blood, and the 30 ml centers have not been able to enroll enough patients to complete the study because it’s too painful for the patients. So we have sort of settled upon 20 mls, and by then the average patient who’s within the first, say, week of having delivered is getting pretty serious radicular symptoms, even if you inject the blood very slowly, and we have to stop and withdraw the needle.
The other thing is that we have some data, and again not randomized controlled high-quality data, to say that if we patch the woman before 48 hours, she’s more likely to need a second blood patch. It’s highly confounded, however, by the fact that we are choosing to patch them earlier based on the severity of their headache. So what we don’t know is if it’s really just a marker for more severe headache.
We do try other things. There’s something called a prophylactic blood patch, which is if you’ve receded an epidural catheter after you’ve made an inadvertent dural puncture at the end of her delivery. Do you just put blood in through to the epidural space through that prophylactically and see if that decreases the headache risk? And the answer is yes in some small studies, but not overall.
If you’ve made the inadvertent dural puncture and thread an intrathecal catheter and use that for the delivery, does that decrease the headache risk? If you do run saline through it, if you don’t run saline through it, if you keep it in for 12 or 24 hours, if you don’t — and these have all been looked at. Some studies suggestive of it, but not compelling. And there are some dangers to leaving an intrathecal catheter in a woman on the labor floor, unsupervised, so to speak, not using it during the delivery but leaving it in there after. So without compelling evidence, most of us will not leave it in.
For reasons that you can probably guess, sphenopalatine ganglion blocks have been a source of a lot of attention and interest. And what is clear is that there is some transient effect. The problem is we’re doing them a million different ways. We’re taking pledgets and putting them near the sphenopalatine ganglion but we can’t get right to it. Some of us are doing it once, some of us are doing it multiple times. Some of us are sending patients home to repeat the procedure at home. Different concentrations, different volumes. And each study has a relatively small number of patients with a different method. And so in the end when you try to aggregate the data, it’s really difficult to tell.
I did see a gentleman outside next to the lumbar puncture kit with a nerve stimulator to go to the sphenopalatine ganglion. Another interesting idea. And what about the greater occipital nerve block? People also try this for their patients with PDPH, their obstetric patients. They do not usually suggest that people do this at home for themselves, but they do do them for the patients. In the studies, again, aggregated in the systematic review, most patients had partial improvement, although about a quarter of them still needed an epidural blood patch. We leave the more fancy procedures to you.
But I worry and I’m just going to show you quickly. I worry because some of our patients, this is a case series. Some of our patients actually have some chronic things that are pretty scary. This I can’t tell whether is an epiphenomenon or truly related, which is we do see a handful of patients who have subcortical vein thrombosis and PDPH. Now since both of them exist — are they related or not? But we also see patients with chronic headache and those are the patients that I think we really have to think about finding their way to you and I ask you how do we do that? And that’s at 3 months, 6 months, 12 months. And there I, you know, there’s one study I flashed up but there are multiple studies like that as well as other outcomes that are tracked with a lot of the symptoms that you’re talking about with your SIH patients, depression, listlessness in other ways, PTSD for us, and it doesn’t seem to make a difference if we’ve given those patients a blood patch or not.
So the recommendations for follow-up from this study, too small to read, were about short-term follow-up. Make sure you don’t lose them to follow-up initially, but after listening to all of you, I really think we need longer-term follow-up and connection to this group. Thank you very much.