A (5:14)
All right, let's recap, shall we? So remember the question said, hey, have a patient intrapartum. She didn't have fever, but mom's heart rate started going up, baby's heart rate started going up. So I started, you know, fluid resuscitation for both of them. Let's stop there for a minute. Yes, absolutely. So if you see maternal heart rate tachycardia, and thankfully it's not some kind of emboli or something else going on and or fetal tachycardia began again. That's a fetal heart rate above 160. Absolutely. Give fluid hydration. Not only will that ensure better uteropacentral blood flow, but it also helps cool body temperature. Because even though the patient is afebrile, the next likely thing that will happen with isolated fetal tachycardia is maternal temperature elevation. So here's the catch, guys. So right now, as we covered in the previous episode, the diagnostic criterion clinically right now that ACOG has for diagnosing intra amniotic infection pivots or builds on the foundation of maternal pyrexia, maternal fever. Okay? And just as not all fever necessarily is infectious because as we talked about in the previous episode, that could be dehydration, it could be a stress response, it could be the sympathetic blockade that affects temperature regulation with an epidural. So not all fever intrapartum is infectious. The problem is we don't have a way to figure out which one is infectious and not in an easily bedside approach. So everybody gets called IAI because we don't want to jeopardize neonatal or maternal sepsis. Plus there's data that just histological inflammation of the chorio and the amnion, that that inflammatory state that the child is in can lead to, you know, poor neurodevelopmental issues. So the idea is if you have fever, get on top of it. However, this is kind of the reverse. What if the baby's heart rate is tachycardic but she's afibrilla? Can you make the diagnosis of IAI since the current guidance from the college. Right now, whether it is isolated maternal fever, which is a temperature of 39 degrees or more, or 38 to 38.9 that repeats in 30 minutes, or suspected intra amniotic infection, which is fever, plus some other clinical factor like fetal tachycardia, uterine tenderness, or, you know, foul smelling amniotic fluid, both of those rest on the idea, the prem, the assumption that the patient's already febrile. But what if there's fetal tachycardia alone? Now I'm talking about normal fetal tachycardia, not, you know, this weird little aberrant, you know, tachycardic spikes in the heart rate. That could be a temporary arrhythmia that happens. Typically that doesn't happen intrapartum. Usually the patient goes into a labor already with it because babies can have episodes of supraventricular attack. Those are physiologic, kind of part of the immaturity of the SA node. They usually, you know, wear themselves out back into a normal rhythm post delivery with the stress of delivery and the transition from intrauterine to extrauterine life. But they look differently on the monitor, right? They have little spikes. Those are called tachyarrhythmias. But I'm talking about heart rate was 120s, 130s, and then maybe she has prolonged rupture and then, lo and behold, intrapartum. Mom's fine, everything else is fine. But baby's heart rate now goes to tachycardic with or without mom having a heart rate above 100 or 110 based on who you read as tachycardia intrapartum for maternal heart rate. So here's a question. If you see fetal tachycardia with or without maternal tachycardia, but the mom is afebrile, can that be intraamniotic infection? The short answer is absolutely. And that is one of the gaps in the current committee opinion, which is 7, 1, 2, remember, just a committee opinion. That's what it literally is. Again, very thankful for my time in the ACOG committees. And that's all it is. Take a look at the data, it goes by consensus, people review it, go up for a vote, see if there's any new or conflicting data. It's a process, but it is just that, it's a committee opinion. So according to that committee opinion, again, 712, there are three main types of intra amniotic infection. Isolated maternal temperature, which we've covered in the last episode, suspected iai, and then of course, physiological chorio, which you won't know until after the fact. Okay? But the clinical ones, isolated maternal fever or suspected iai, both rest on the premise of fever. Okay, so you have to have fever. There really should be a caveat in there which says sometimes guys, sometimes using the baby as a vital sign because the fetus is its own set of vitals, specifically the heart rate, that is the first indication of later development of intra amniotic infection. So in this case, the attending. Absolutely correct, totally evidence based. It is absolutely possible that fetal tachycardia be the first presenting sign of suspected IAI before manifesting maternal pyrexia. So let me give you this data. There was actually some data that looked at this and one was a retrospective. So take it for what it is. But it's a retrospective review of 57 cases. Five, seven. I get it. It's not thousands, but it makes the point very well here. Now, these were all cases with histologically confirmed chorioamnionitis and or umbilical cord inflammation. That's called funicitis. Okay, none of these mothers had elevated temperatures at the point when fetal tachycardia was first documented. So once again, end of 57, they said, hey, these placentas have histological chorio andor finucitis. In other words, there's definitely some kind of inflammation going on here. And then when they went back, looked at the reviews, when fetal tachycardia was first documented intrapartum, none of those had elevated temperature. In other words, for sure, if mom gets a temperature first and then baby gets tachycardic, no Brainer, we get that, but what about the reverse? Is it possible for the baby to first show the tachycardia before the temperature? And the answer is yes. The pathophysiology of this is very, very clear. The baby is very sensitive to bacterial or microbe invasion. So the first thing that can happen, even beating at times maternal temperature elevation, is that the baby triggers a fetal inflammatory response syndrome. Furs. All right, so in adults, we get systemic inflammatory response syndrome, sirs. Well, in the baby, you get furs. All right, so fetal inflammatory response syndrome, which is a response to the interleukins, namely interleukin 6 and 8, that are elevated in the amniotic fluid, typically, again, with either generalized inflammation, infection, or microbial invasion. So the baby says, hey, I'm being invited here, and triggers up. That causes a catecholamine flare. So the baby's heartbeat goes up even though mom is afebrile. Now, at some point, there's the tipping point where now it becomes not just a fetal response, but the entire intrauterine cavity is inflamed, infected. And now that triggers the maternal response, which is pyrexia. This is very similar to septic patients, guys who, you know, that get a little confusing because you're like, wow, I don't know. I mean, but, you know, she's not febrile, but she surely looks shocky. Her blood pressure is down. Her pulse is up. She looks terrible. Her lactate is up, but she's hypothermic. And the reason is the same thing is that at some point, the catecholamines go, oh, hell. Fever's not working. Let's just code. We're in extreme. Code, sirs here. Code, sirs here. And these patients, even with sepsis, get hypothermic. So just as sepsis can exist without fever, yes, it is true. IAI especially early on, can happen without fever, and the baby is the first to show it. Okay, so the baby first gets his first reaction. That can then follow with mom's tachycardia, and then, boom, there's a temperature spike. We've done this ourselves on the ward. Happened on my last call shift with one of the residents was like, hey, baby's now tacky. She had a prolonged rupture. I'm like, amp and gent, baby. You got to start an amp inj. It was the exact same situation, but she's not febrile. Actually, she was like 99 said. Yeah, well, 99 is not normal either. I mean, it's not 100.4, but 99 is kind of a low grade of something going on there. She's got prolonged rupture and baby's tachy, she's going to get fever. And as we were loading the antibiotics, of course she spiked her temperature. So yes, it is possible to have IAIAs and mom never show a pyrexia response, especially if the tachycardia is recognized quickly in the appropriate clinical context and then started antibiotics quickly. Mom may not mount a temperature. So if you give antibiotics because you suspect IAI based on fetal tachycardia or maternal tachycardia or both together, which is increases the specificity, then yes, pediatrics and neonatologists need to be made aware that potentially this is an IAI even though she is without fever. And send the placenta off, send an umbilical cord gas because it is very well accepted that you can treat them the same. That highlights guys, the gap in the current guidance from the college. Remember again, no beef with them. Actually I think we reviewed this when I was still on the board. That ACOG's committee opinion, which is 71 2, originally out in 2017, but it was reaffirmed in 2025 this year. That's one of the gaps, guys. That's one of the gaps is that it relies as its diagnostic criterion on fever. However, it is possible to have fetal tachycardia show up first as a fetal inflammatory response and then tachycardia with fever will then occur. So remember right now, just to make it fair, the executive summary, the expert workshop on IAI came up with these three diagnoses based on febrile response in the mother. And just to recap that isolated maternal fever is either 39 degrees Celsius or a temperature of 38 to 38.9 degrees Celsius that persists when it's repeated after 30 minutes or suspected intramniotic infection, which is a temperature above 38 degrees with one or more of a clinical marker like maternal leukocytosis, purulent cervical discharge, or there is fetal tachycardia and then confirmed intraamniotic infection, which is based either on a positive amniotic fluid tap, which very few people do, or based on placental histology demonstrating inflammation of the chorion and the amnion. So as we do this very quickly, is it reasonable to diagnose intra amniotic infection in a non tachyarrhythmic, meaning you don't have little weird spikes on the, on the ECG? It's a set rhythm, but it's above 160, can you have fetal baseline tachycard in the setting of a normal fetal baseline and the mom be called iai? In other words, can you make that diagnosis before she actually gets fever? And the answer is yes, even though the current criteria requires fever as a diagnostic criteria. And the gap in that is that it is possible for fetal tachycardia and or maternal tachycardia to be the first presenting signs. And this has to do with. With the fetal firs response. Fetal inflammatory response syndrome. All right, I think we've done what we're supposed to do here. This was gonna be super quick. I just wanted to highlight the wonderful question that one of our podcast family members sent in. So thank you for that. And it just goes to show that our clinical diagnosis of chorio is not very sensitive and it's not very specific, but it's the best that we have outside of tapping the amniotic fluid and sending for interleukins, which is gonna take forever. Tumor nec factor or gram stain, which may be faster, but no one's going to want to get a tap, like in between contractions. Could you imagine? Ma', am, I know you're 6cm, but I need to stick this needle under ultrasound guidance to get some fluid out. Yeah, we're not doing that.
