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Perfect. We'll give it another minute or so and we'll do instructions. Ok, so it's five past, if more people drink, that's fine. Um So yeah, I want to welcome everyone today. Thank you for joining us this evening. Um I want to welcome you to the next part of our NT series, which is our National Anesthetics Teaching series. And our talk this evening has been organized by Manchester and we've kindly got um doctor YF who's gonna give us a talk on obstetric anesthesia. So I'd like to hand over to doctor. Thank you so much. So, hi. Yes. Um Thank you for that introduction. My name is Danny. I'm one of the anesthetic consultants at, with and show and at ST Mary's um which is um one of the big tertiary centers um here in Manchester. Um And um yeah, I'm gonna spend the next hour giving you a bit of an introduction to obstetric anesthesia. Um and I was not very long to tell you everything I know about obstetric anesthesia. So, um I will um I will do my best just to give you a bit of a um a bit of an introduction. Um so things we're gonna go through. Um, first I'm just gonna go through what exactly what an obstetric an is does. Um, then, um, I'm just gonna go over a bit about anatomy and physiological changes that occur during pregnancy because these are really important to us as, um, as obst anesthetist. Um, then I'll briefly talk about the two kind of main things really that we do in, in, in obstetrics which is provide labor analgesia um and also providing anesthesia for um surgical cases. Um So, first of all, no, what does an obstetric anesthetist do? Um I mean, unfortunately, I can't, we can't be interactive on, on this kind of forum. But um I think the thing that everyone thinks we do is we just put epidurals in and that is, um and, you know, maybe 20 years ago, do you know the anesthetist delivery suite was seen more of it as a bit of a technician and that we were just called to go to room two and put an epidural in, go to room five and put an epidural in, you know, and that was seen as our role, but it's very different now and we are truly part of the MDT on, on delivery suite and we work together with the Obstetricians and the mid and the midwives um to create um good peripartum care for all of our patients. Um So other things that we do. So we're involved in resuscitation, you know, um particularly I deal with a lot of patients who bleed, um I give lots of blood during my job. Um but we also deal with um the um medical complications that occur and those particularly during pregnancy such as preeclampsia. Um and also women who are septic and those who um come to us with lots of different medical um medical problems that can occur around pregnancy, even those related to pregnancy. All those just that happen whilst someone is pregnant. Um So when the anesthetist tends to be more of a kind of peripartum physician on delivery suite. Um and um and with an aging population, um and also with a, a population now that um for example, I work in a cardiac center. Um so we get women who have um um got congenital heart disease that, you know, 2030 years ago, wouldn't have survived until adulthood. Now presenting to us pregnant. Um So, um we're a really important part of the um MDT. Um And um and yeah, we all work really closely together um doing lots of ward rounds and making sure that we're um um aware of all the patients that are on our delivery suite. And um so nothing comes as too much of a shock if we need to take somebody to, to the theater. So first we're gonna just talk about the um some of the physiological and anatomical changes that occur during pregnancy. So, to start with respiratory, obviously, I'm anesthetist. That's the first thing I think of. Um And um we get lots of changes um mainly due to kind of hormonal but, and mechanical factors. Um So the women do tend to be a bit more um challenging when it comes to intubation, that's due to multiple factors. So they've got increased breast size that actually makes it a bit more difficult to put a laryngoscope into somebody's mouth. Um And um so these days, you know, video laryngoscopy has been a real game changer with um with regards to this, um also everything becomes a bit more swollen when you're pregnant, so that can cause swelling around your um your glottis. And so it can sometimes be more difficult to actually put the tube in. So often you need to put down um a smaller tube, this can get worse um in patients that have got preeclampsia and also you get um nasal congestion. So women are more prone to having epistaxis. So we try to avoid putting um things like MP airways in nasopharyngeal airways because they can cause um bleeding. So women do hyperventilate um when they're pregnant. And um well, you, so you'd have thought that someone's tidal volume would actually reduce when you're pregnant because um you'd have thought that, you know, the um the physical um physical pressure of the enlarged abdomen onto the chest would reduce your lung volume, but it actually doesn't, your tidal volume increases by about 40%. And that's because the progesterone, it causes everything to be more relaxed. And so you get spleen out of your um of your ribs. Um So you get an increase of tidal volume and you also get a very slight increase of respiratory rate and the combination of those causes you minute ventilation to increase and that results in a drop in your CO2. And so you get a mild respiratory alkalosis, but just a note, your respiratory rate only goes up a tiny, little bit. Ok. So it's not normal breathless during pregnancy and actually feeling breathless is a red flag. And that should um um make you assess the patient to see if there's actually something wrong and you shouldn't just put that down to, oh they just pregnant. Also, you get um increased oxygen consumption because um you've got the increased the metabolic demands of the fetus, but also this increased work of breathing as well. It increases the oxygen demand on the body. So this is just a bit of a graph just to show that. So you get a um an increase in tidal volume with a slight increased respiratory rate and this results in an increase um in your minute ventilation and your increase in gestation. Now moving on to cardiovascular changes. Um so your cardiac output starts to increase from five weeks from conception. So it's really early um early on that these changes start to um start to occur and um so you get an increase in stroke volume. And this is because you get an increase in plasma volume and that um causes a increasing enddiastolic volume and then results in an increase in stroke volume. So with your Frank staling curve, you also get an increase in your heart rate, but you also get a reduction in your systemic vascular resistance. And this is due to progesterone and it causes everything to vasodilate. You get an increase in cardiac output because of a combination of your increase in stroke volume and your increase in heart rate. And this um increases by about 40% by the end of your um your first trimester. So it goes up really significant and this is why women who have cardiac disease can worsen during pregnancy because you get this increased stress on the heart. But your BP actually does go down for most patients. And that's um despite having an increase in cardiac output and this is mainly because of your increase um your reduction in systemic vascular resistance. Um what's really important to know is that your blood flow to the uterus increases massively um during pregnancy and it increases to about 700 mils per minute by full term. And what's why this is really relevant is because, you know, when a woman is bleeding, um um when they've given birth, if you think that um you know, if the blood flow is 700 mils per minute it means within 10 minutes, a woman can lose their entire circulating volume onto the floor. Um So this is why it's really important to recognize when someone is bleeding, bleeding early and to resuscitate them very, very quickly. The there is um the uter of placental circulation. So, I mean, by um so the blood flow from the uterus to the placenta um actually has what we call no autoregulation. And that means that it's just completely um the blood flow to the uterus and the blood flow to the placenta, sorry is completely dependent on blood flow to the uterus. So, um if the woman's BP drops, the blood flow to the uterus reduces. So blood flow to the placenta reduces. And so you get fetal compromise. So that's why it's really important. So happy, happy mum, happy baby. And also what's really important in pregnancy is this aortocaval compression. And so what that means is that when