Transcript
Speaker: Welcome to Critical Matters, a sound critical care podcast covering a broad range of topics related to the practice of intensive care medicine.
Speaker: And now, your host, Dr. Sergio Zanotti.
Speaker: Caring for critically ill pregnant patients poses a unique set of challenges for the intensivist.
Speaker: There is added stress of more than one life at risk and constant concerns for preventing iatrogenic fetal damage.
Speaker: Pregnant patients have unique physiological changes with important implications for critical care.
Speaker: Finally, there are a number of conditions unique to pregnancy that the intensivist might not care for on a regular basis.
Speaker: This will be a two-part podcast on critical care in pregnancy.
Speaker: Today, in part one, we will cover conditions unique to pregnancy that may result in critical illness.
Speaker: In our future episode, on part two, we will discuss general conditions that may result in pregnant patients coming to the ICU.
Speaker: Our guest is Dr. Stephen Lipinski.
Speaker: Dr. Lipinski is director of the intensive care unit at Mount Sinai Hospital in Toronto and a professor of medicine at the University of Toronto.
Speaker: He's a practicing intensivist and pulmonologist.
Speaker: Dr. Lipinski has a clinical and research interest in critical illness and respiratory disease in the pregnant patient.
Speaker: He is a member of the editorial board of the Journal of Obstetric Medicine, and he sits on the steering committee of the North American Society of Obstetric Medicine and the executive of the Women's Health Network of the American College of Chest Physicians.
Speaker: Other clinical and research interests include mechanical ventilation, continuous renal replacement therapy, and mobile computing in medicine.
Speaker: He has authored over 100 peer-reviewed articles and 40 book chapters on these topics.
Speaker: Stephen, welcome to Critical Matters.
Speaker: Thank you.
Speaker: Thanks for inviting me.
Speaker: So I think that a good place to start would be for us to understand a little bit of why do patients who are pregnant end up coming to the ICU?
Speaker: Right.
Speaker: So the reasons for coming to the ICU really vary according to region and facilities available in a hospital.
Speaker: On average, about three patients per thousand deliveries end up in the ICU.
Speaker: The commonest indication in most areas is pregnancy-related hypertensive disorders, so preeclampsia and complications of preeclampsia, including pulmonary edema, seizures, renal failure.
Speaker: After preecampsia, other conditions include postpartum hemorrhage and sepsis, either obstetric-related sepsis or non-obstetric sepsis.
Speaker: And then there are a number of other reasons why pregnant women may come to an ICU, including, for example, diabetic ketoacidosis.
Speaker: How do these women do compared to women who are critically ill and are not pregnant in terms of mortality?
Speaker: Again, this is difficult to assess because mortality varies so significantly in pregnancy across regions of the world with a hundredfold difference from about five per 100,000 in some areas to over 500 per 100,000 in other areas.
Speaker: But in general, pregnant women are young and often without much comorbidity.
Speaker: So generally, they will do better than the non-pregnant patient who is often older with significant comorbidity.
Speaker: And from your perspective, Stephen, what are some of the challenges that intensivists face when dealing with pregnant patients?
Speaker: Why is it so hard for us?
Speaker: Well, there are three issues which you actually mentioned in your introduction.
Speaker: One is that there are some physiological changes which take place in the pregnant patient related to pulmonary physiology and cardiac physiology.
Speaker: The second is the presence of the fetus, which gives all of us some concern in terms of drug therapy, radiation exposure, and other concerns that we're looking after to lives.
Speaker: And thirdly is that these pregnant women can present with unusual conditions that the intensivist does not see in other situations, including preecampsia, HELP syndrome, and amniotic fluid embolism.
Speaker: So all of this adds up to a very concerning situation for the intensivist.
Speaker: So I think it's a good leeway into talking a little bit about physiology.
Speaker: As intensivists, I think we always are very interested in understanding the physiological changes of critical illness, but there are some normal physiological changes in pregnancy that have significant implications for how we treat patients when they become critically ill.
Speaker: Could you comment on some of the most important features of the physiology of pregnancy that the intensivist should be aware of?
Speaker: Okay, so firstly from a respiratory point of view, one of the issues that comes up is that pregnant women have upper airway edema and friability, and this is mediated by hormones, most likely estrogen and human placental lactogen.
Speaker: And this upper airway edema and friability can make intubation more difficult.
Speaker: They may need a smaller endotracheal tube, and visualization may be a lot harder.
Speaker: Then from a functional point of view, the pregnant patient has an increased respiratory drive.
Speaker: This is mediated by progesterone.
Speaker: So she actually takes larger tidal volumes than the non-pregnant patient.
Speaker: And the net effect is quite a big increase in minute ventilation
Speaker: and specifically alveolar ventilation because dead space is unchanged.
Speaker: So the pregnant woman in the end ends up with a compensated respiratory alkalosis.
Speaker: The CO2 level is reduced to about 30 millimeters of mercury compared with a non-pregnant normal of 40 millimeters of mercury.
Speaker: Associated with this, there's an increased oxygen consumption and CO2 production by the fetus and placenta and uterus reaching about 30 percent above baseline.
Speaker: So the pregnant woman is at risk of hypoxemia because they have increased consumption and they also have a reduction in their total lung volume and functional residual capacity.
Speaker: cardiac point of view, there's an increase in cardiac output which starts early in pregnancy and peaks at around 28 weeks associated with an increase in blood volume.
Speaker: This is a problem if the patient has some limitation in cardiac output, for example, stenotic valvular lesions, aortic stenosis or mitral stenosis, as well as pulmonary hypertension which is going to limit blood flow through the pulmonary vascular bed.
Speaker: So patients with underlying cardiac disease can have significant problems as cardiac output tries to increase in pregnancy.
Speaker: Other more minor changes that need to be
Speaker: understood is that renal blood flow and glomerular filtration rate are actually increased in pregnancy.
Speaker: So the normal creatinine is a little lower in the pregnant patient than in the non-pregnant patient.
Speaker: So it may be considered a slightly elevated creatinine in the non-pregnant patient may be quite significant in pregnancy.
Speaker: And could you comment on some of the hematological issues, so specifically thrombocytopenia, anemia, and peripartum leukocytosis?
Speaker: Yeah, so there is a physiological anemia of pregnancy largely related to hematology.
Speaker: hemodilution as the blood volume increases and this is a physiological phenomenon but pregnant patients are clearly at risk of iron deficiency anemia because of the increased iron requirements during pregnancy.
Speaker: Platelet count can also drop in pregnancy.
Speaker: There is a physiological thrombocytopenia or gestational thrombocytopenia that can occur
Speaker: But many of the life-threatening complications of pregnancy, such as HELP syndrome and fatty liver of pregnancy, can be associated with dramatic drops in platelet count.
Speaker: So this needs to be monitored quite closely.
Speaker: There can be a small rise in white cell count during pregnancy as well.
Speaker: Is there any tips or any particular aspects of a thrombocytopenia that would make you more concerned?
Speaker: Like you said, it's common sometimes.
Speaker: It can occur normally, but it also can be the precursor or an indicator of something more serious going on.
Speaker: I think it would really be the bigger picture of the patient.
Speaker: If the patient is relatively well without any other problems, then it would be less concerning.
Speaker: But if there's associated liver disease or hypertension, suggested preeclampsia, that would be a big concern.
Speaker: So all taken into the big picture of the patient.
Speaker: And the last thing I think that is important for intensivists, or one more thing that's important that maybe you can comment on, are the anatomical changes and how those impact either our diagnostic approach when we're trying to figure out abdominal pain or even our resuscitation efforts when we have a patient who's maybe 36 weeks and going into shock.
Speaker: Yes, so one issue with these sort of anatomical changes relates to trauma in pregnancy.
Speaker: So the enlarged uterus is going to push all of your abdominal contents into one small area.
Speaker: So, for example, penetrating trauma to the abdomen would usually involve the uterus.
Speaker: But if it does involve the bowel, you can have major bowel injury because the bowel is all squashed into one small area of the abdomen.
Speaker: Similarly, the uterus is protected in the pelvis until about 12 weeks, and after that it's up and exposed in the abdomen.
Speaker: So there are major anatomical changes.
Speaker: This can also influence the
Speaker: location of pain, for example, the patient with appendicitis, if the bowel is pushed around the pain may be in a different area to where you'd normally expect it.
Speaker: The peritoneum also being chronically stretched in pregnancy can cause less peritoneum and less peritoneal pain than in the non-pregnant patient.
Speaker: Excellent.
Speaker: And I think that it's important to emphasize to our listeners that understanding what's normal, what might be different in the pregnant patient will have implications for a lot of the treatments and approaches when they become critically ill.
Speaker: And we'll touch upon these as we talk about different conditions.
Speaker: But I think this is a good opportunity to jump into some of the conditions that are unique to pregnancy, Stephen.
Speaker: And I would like to start with obstetrical hemorrhage.
Speaker: We work in a lot of community hospitals, and that seems to be one of the frequent reasons why patients end up coming to the ICU or the surgical ICU.
Speaker: And I think that it would be nice to maybe start by defining what is an obstetrical hemorrhage and what's its frequency.
Speaker: Yeah, so the definitions and the frequency are difficult, but a lot of variation around the world.
Speaker: I have seen a number of about 1% of pregnant women will have significant hemorrhage.
Speaker: Now the pregnant woman is
Speaker: primed to tolerate hemorrhage.
Speaker: So the increased blood volume and actually the physiological anemia make them tolerate hemorrhage better than the non-pregnant patient.
Speaker: It's said that a normal vaginal delivery is associated with about a 500 mil blood loss and a caesarean section, about a liter, which is well tolerated, but anything above a liter would be considered an obstetric hemorrhage.
Speaker: I guess the major definition would be how panicky the obstetrician and staff looking after the patient are in the face of the hemorrhage and how poorly she tolerates it.
Speaker: So if the pregnant woman is hypotensive, that's going to be a big problem.
Speaker: Now in my practice, I must say we seldom are acutely involved in the hemorrhage management that's handled by our obstetricians and
Speaker: obstetric anesthesia stuff, but I can imagine in a smaller hospital, the intensivist would be more directly involved.
Speaker: And what would you think it would be the role of the intensivist?
Speaker: Obviously, this is always a team effort, and there are some decisions that ultimately do not fall in our lane, but from your perspective, what would be the important things for the intensivist in the community who might be getting a patient postpartum who's bleeding?
Speaker: What is their responsibility, and what would you focus on?
Speaker: Yes, I think it would be the standard resuscitative roles of the intensivist that may be missed by the obstetrician.
Speaker: So getting several large-bore IVs in place to allow rapid transfusion when blood is available, resuscitation with crystalloid initially, but blood as soon as you can.
Speaker: keeping an eye on the coagulation status if the patient needs fresh frozen plasma.
Speaker: So all the routine things that you would do in any case of hemorrhage that the obstetrician may be sort of worrying more about the uterus and the surgical aspects.
Speaker: The one thing that the intensivist can add to the sort of obstetric management is early administration of tranexamic acid.
Speaker: It may be forgotten by the obstetrician, but there's good data now that a gram of tranexamic acid within three hours of onset of hemorrhage has an effect on outcome.
Speaker: And it seems that...
Speaker: these bleedings become difficult in terms of decision-making because the ultimate treatment, which is usually surgical removal of the uterus, is something that most obstetricians obviously would not want to impose lightly on a young woman at childbearing age.
Speaker: But it also seems that if we miss the boat and the patient gets to a DIC status, it becomes very complicated then to stop the bleeding.
Speaker: Any comments on that tension and how we can help or understand what's going on?
Speaker: Yes, so often it does come to a surgical intervention.
Speaker: There are a lot of other things that the obstetrician can do.
Speaker: So in our practice, it's quite common for them to insert intrauterine balloons, a Bacri balloon or some other type of balloon to tamponade the uterus.
Speaker: We make use of interventional radiology quite extensively now to embolize bleeding arteries or non-specifically embolize iliac arteries.
Speaker: But if that fails, then the next step would be a surgical and often a hysterectomy, which is obviously going to be a very complex procedure in the pregnant patient, particularly with shock.
Speaker: So the other disease that you mentioned as being specific or unique to pregnancy that might be a frequent cause of patients coming to the ICU is the group of disorders known as heart-intensive disorders of pregnancy.
Speaker: Could we talk a little bit about what are the different types of hypertensive disorders of pregnancy, of how do we classify these, and then maybe start talking more specifically about preeclampsia?
Speaker: Yeah, so there are a number of classifications and really largely used for research purposes to identify different groups of patients to make sure that we are talking about the same patient in terms of studies.
Speaker: So there are women with chronic hypertension who continue with their hypertension in pregnancy.
Speaker: There are women with preeclampsia, which is a specific condition with a number of complications.
Speaker: And there are also some women who develop gestational hypertension, which is just a high blood pressure, but without all the other multi-organ effects of preeclampsia.
Speaker: I think that it's common currency for intensivists to manage the extremes of any vital sign, blood pressure being one of them.
Speaker: And historically, people have always talked of drugs that are better for pregnant patients than the fetus.
Speaker: And for many years, drugs such as hydralisine have been talked about historically as being good choices to manage high blood pressure.
Speaker: Now, hydralisine is not necessarily a great drug for the ICU because of its long actions and inability to titrate.
Speaker: In general, when you're trying to manage hypertensive emergencies or very high blood pressures with vasoactive medications in the ICU, what do you recommend today?
Speaker: What are better options?
Speaker: Yeah, so the problem with pregnancy is that it's always old drugs.
Speaker: Any new drug that comes out, there's very little experience in pregnancy, and there's a reluctance to use new drugs in pregnancy in case there's some harm that has not yet been identified.
Speaker: So we are really limited to very old drugs.
Speaker: As you say, hydralazine is a commonly used one.
Speaker: Another very common and old oral drug would be alpha-methyl-dopa.
Speaker: which you'll only see in the pregnant population.
Speaker: But other drugs that are used are labetalol and nifedipine.
Speaker: Nifedipine is an oral drug and labetalol as an intravenous infusion.
Speaker: or intravenous boluses, as well as given orally.
Speaker: Now, they're not very short-acting.
Speaker: The labellol is still going to last for hours, but this would be the sort of intravenous drug of choice if you don't get an effect with oral nifedipine or hydralazine.
Speaker: Any experience with nicardipine drips?
Speaker: Not in Canada.
Speaker: I don't believe it's easily available, so we don't use that here, but I think that may be a reasonable choice.
Speaker: And what about preeclampsia?
Speaker: Can you talk a little bit about when we should suspect it?
Speaker: I would imagine a lot of times the patient comes to us with a diagnosis of preeclampsia, but just what defines preeclampsia?
Speaker: What do we understand of its pathophysiology today?
Speaker: And then we can talk a little bit more about the treatment of its complications.
Speaker: Yeah, so preeclampsia, the mechanisms are really unclear.
Speaker: There's a lot of work looking at it.
Speaker: Most recently, there's some data of a substance called SFLIT1, which is produced by the placenta, and this blocks a number of angiogenic factors, so VEGF and platelet growth factor.
Speaker: And this causes major maternal endothelial effects with vasospasm and inflammatory changes.
Speaker: But the practical presentation is with hypertension and proteinuria after 20 weeks gestation usually.
Speaker: There's also been some recent data looking at different hemodynamic subgroups.
Speaker: Some women are hypodynamic with a low cardiac output and a high SVR, and their treatment would be vasodilation, whereas others have a high cardiac output and a low SVR where beta blockade may be more effective.
Speaker: But the big problem with preeclampsia is the multi-organ complications which can result in ICU admission.
Speaker: Examples would be the development of eclampsia, so this would be seizures related to preeclampsia.
Speaker: The high blood pressure can have all the adverse effects of hypertension in anyone, including intracranial bleeds, cardiac failure with pulmonary edema, and even vascular rupture, say, aortic aneurysm or other vessel ruptures.
Speaker: These patients are also at risk of renal failure, which could get them admitted to the ICU.
Speaker: So it's a multi-organ effect and the treatment in addition to controlling the blood pressure to prevent the hypertensive complications is really delivery of the baby.
Speaker: And that becomes a discussion between the obstetrician and the neonatologist to decide at what point is delivery least harmful to the baby and most beneficial to the mother.
Speaker: So there are instances in which delivery might be delayed according to other factors and we were more of a conservative treatment, is that correct?
Speaker: Yeah, so it's not that there's an absolute indication to deliver right away.
Speaker: And there are certainly cases and data on monitoring women and waiting.
Speaker: And for the neonatologist, each day that you're delaying delivery is a significantly better outcome for the baby.
Speaker: So it's a weighing up of the risks and benefits, but there is often a time, an indication to delay delivery.
Speaker: particularly at much younger gestations.
Speaker: And in terms of definitions, how do we define severe preeclampsia, which would be what we would be mostly concerned with as intensivists?
Speaker: In the ICU, I would imagine it's pretty severe.
Speaker: So it would be related to the complications as well as the level of blood pressure, but I think anyone with significant organ dysfunction is going to be a concern.
Speaker: And is there any specific treatments that we use for proeclampsia or it's mostly supportive care of the different organ dysfunctions?
Speaker: Yeah, so supportive care and delivery and the one specific treatment is the magnesium infusion which is aimed at preventing seizures and also for treatment of seizures.
Speaker: So this is given in different ways in different parts of the world.
Speaker: In some areas used as an intramuscular injection of magnesium, we would give a bolus of IV magnesium, so usually about 2 grams and then a roughly 1 gram per hour, sometimes as high as 2 grams per hour magnesium infusion.
Speaker: The problem with magnesium infusions is if the patient has renal failure, which is not uncommon with pre-ecamcer, you can get accumulation of magnesium.
Speaker: and toxic magnesium levels are going to cause two major effects.
Speaker: One is muscle weakness, which can cause respiratory muscle weakness, and this can be monitored by looking at re-tendon reflexes.
Speaker: And the other is cardiac conduction defects, so you can get heart block.
Speaker: If these complications happen, then you obviously need to discontinue the magnesium infusion and the effects can be reversed with intravenous calcium because the magnesium is largely acting as a calcium blocker.
Speaker: But a magnesium infusion is important in the management and prevention in preecampsia.
Speaker: And this is one of the aspects of pharmacotherapy that actually has been well studied, I understand, in pregnant women with randomized studies that have clearly shown that magnesium is the drug of choice for the prevention and for the treatment of seizures once eclampsia develops.
Speaker: Is that correct?
Speaker: Yeah, definitely.
Speaker: It's superior to other antiepileptic drugs, although if you do have a case of refractory seizures, it's not uncommon to add conventional antiepileptic drugs, but the magnesium is the first choice for prevention and for treatment and usually very effective.
Speaker: Could you comment a little bit, Stephen, on the postpartum manifestation or presentation of eclampsia?
Speaker: Because it's not common, but it can occur.
Speaker: And it's always something that has interested me since we talk about delivery as being part of the treatment, but it can occur postpartum.
Speaker: Yeah, so that's, I think, most important thing is just to recognize it, that a woman who's maybe in the first 24 hours, maybe 48 hours postpartum, who develops something that looks like preecampsia or develops a seizure, this may well be preecampsia, not to ignore that diagnosis just because she has recently delivered.
Speaker: Again, the mechanisms are really not clear, but there are these ongoing issues.
Speaker: endothelial abnormalities that predispose.
Speaker: And the management would be the same with supportive care and magnesium.
Speaker: Now there's some literature that magnesium after delivery is less effective or in the woman who's had a course of pre-delivery magnesium, there's not a good reason to continue it more than six hours afterwards.
Speaker: But I think if there's new onset of preecampsia, they should still get the same infusion.
Speaker: And I think that just to try to put things together as we keep discussing, an example would be you're talking about preeclampsia as a disease that is unique to pregnancy, renal failure being one of the...
Speaker: manifestations of organ failure, and earlier you were alluding to some of the physiological changes in the increased cromelorefiltration rate, we should be, in patients who are in the ICU with preeclampsia, very sensitive to small changes in the creatinine, right?
Speaker: Because what might be considered okay for a non-pregnant woman might be the initiation or the precursor of a patient going through renal failure with preeclampsia in terms of creatinine.
Speaker: Yeah, definitely.
Speaker: And, you know, in the ICU, I think with what we normally see outside of pregnancy, older, sicker patients, you know, slightly elevated creatinines are very common in our patients, and we don't take a lot of note of it.
Speaker: But if you consider these are young patients who normally have a quite significantly reduced creatinine, something that's slightly elevated should be of significant concern.
Speaker: Excellent.
Speaker: So let's talk a little bit about the HELP syndrome.
Speaker: You had mentioned it earlier.
Speaker: And my question is, I understand that we don't fully know the exact pathophysiology, but is it similar to preeclampsia?
Speaker: Is it a different flavor or different disease?
Speaker: Could you tell us what the HELP syndrome is, Stephen?
Speaker: Yeah, so it's often associated with preeclampsia but may occur without significant blood pressure changes and may also have onset in the postpartum period.
Speaker: But these are patients who develop a hemolytic anemia.
Speaker: They have elevated liver enzymes, so that's H for hemolytic anemia, EL for elevated liver enzymes, and LP meaning low platelets, so thrombocytopenia.
Speaker: So this is probably part of a spectrum of thrombotic microangiopathies.
Speaker: Other conditions including TTP and HUS often being in the differential diagnosis and may be difficult to differentiate between these various conditions.
Speaker: And in terms of... Go ahead, sorry.
Speaker: So the HALP syndrome women would normally present with abdominal pain and nausea and vomiting and on blood work have elevated liver enzymes and the thrombocytopenia as well as a microangiopathic hemolytic anemia.
Speaker: And they can go on to get very sick, so they can develop renal failure and ARDS.
Speaker: And one of the potentially catastrophic complications that we worry about is intrahepatic hemorrhage.
Speaker: So they can bleed.
Speaker: Now, initially, this can be confined and show up on CAT scan or ultrasound as a subcapsular hemorrhage, so hemorrhage under the capsule of the liver.
Speaker: But if that liver ruptures, they can bleed freely intraperitoneally, and they've got low platelets and sometimes a DIC, and this can be a catastrophic event.
Speaker: So can we talk a little bit more about the subcapsular hematoma?
Speaker: Because, like you said, that's something that classically is associated with health syndrome and can have catastrophic consequences for patients if it ruptures.
Speaker: So first, in terms of diagnosis, it sounds like we should suspect it in patients who have persistent right upper quadrant pain,
Speaker: abdominal pain in the context of laboratory findings consistent with HELP.
Speaker: Is that correct?
Speaker: Yeah, so a patient with HELP syndrome, so low platelets and liver enzymes, who has acute right upper quadrant pain, some form of imaging, either ultrasound or CAT scan would identify the subcapsular hemorrhage.
Speaker: And essentially the management is just close monitoring and expectant, have some large IVs in, make sure you have blood available,
Speaker: make sure you've identified how to contact your interventional radiologist and your hepatobiliary surgeon if you have one available.
Speaker: So in terms of treatment, we would correct the coagulation profile.
Speaker: It transfuses necessarily probably bed rest and observation trying to prevent the rupture.
Speaker: In case of rupture, you mentioned interventional radiology, so clearly embolization of those vessels is an option.
Speaker: Yeah, that would definitely be an option if you have quick access to that.
Speaker: And otherwise, surgical intervention, either a hepatobiliary surgeon who's familiar with the anatomy and area or alternatively a trauma surgeon because this is not too different to a ruptured liver related to trauma.
Speaker: And in those patients who rupture, Stephen, I presume that without active intervention, the mortality is probably very, very high.
Speaker: Is that correct?
Speaker: Yes, I mean, that's very uncommon, but it would be a major catastrophic event.
Speaker: Okay.
Speaker: Are there any specific therapies for HELP syndrome other than supportive care?
Speaker: We talked about transfusion.
Speaker: We talked about managing the respiratory failure or other organ dysfunctions.
Speaker: Like I know that I've seen small studies with steroids, with plasma exchange.
Speaker: Are any of those actually proven to work?
Speaker: Yeah, there's several small studies with steroids suggesting a more rapid resolution of the thrombocytopenia, so the platelet count coming up a little more quickly with steroids.
Speaker: But the more recent studies have really not confirmed this.
Speaker: So some obstetricians would still give steroids, others wouldn't.
Speaker: The benefit is not clear.
Speaker: The whole plasmapheresis thing is also not clear.
Speaker: As I mentioned earlier, this condition can be confused with thrombotic thrombocytopenic purpura, where plasmapheresis would have a role.
Speaker: And so if the HELP syndrome does not improve within about 72 hours after delivery, you really need to rethink the diagnosis.
Speaker: And maybe this is TTP, in which case plasmapheresis with fresh frozen plasma would be helpful.
Speaker: And you mentioned that from a differential diagnosis standpoint, clearly the microangiopathic hemoidic anemia and the platelet dysfunction are
Speaker: makes us think sometimes of TTP or HUS.
Speaker: What about the liver enzymes?
Speaker: Can you comment a little bit on, is fatty liver of pregnancy something that could present similarly?
Speaker: Yeah, there's a lot of overlap as well with fatty liver of pregnancy.
Speaker: One thing,
Speaker: Biggish difference is that fatty liver pregnancy is usually only quite late in pregnancy, so sort of third trimester, maybe 36, 37, 38 weeks, whereas HELP syndrome can occur a lot earlier.
Speaker: So if it's early gestation, you know, in 28 weeks, it would be very unlikely to be fatty liver, much more likely to be HELP syndrome.
Speaker: But, you know, all of these conditions is considerable overlap.
Speaker: So the other disease that's pregnancy specific that I think is a lot of interest for intensive is because of the pathophysiology and the dramatic presentation is amniotic fluid embolism.
Speaker: I think that our understanding of what causes amniotic fluid embolism has changed over time.
Speaker: Could you tell us what the current understanding of the pathophysiology and what amniotic fluid embolism really is?
Speaker: Yeah, so again, not a lot of clarity.
Speaker: So clearly there's amniotic fluid that's entering the venous circulation, so that requires some kind of tear or rupture of veins and some kind of pressure effect, either labor or some manipulation of the uterus.
Speaker: And the mechanism unclear, there are some theories that it may be related to
Speaker: humoral factors in the amniotic fluid causing acute pulmonary hypertension and myocardial dysfunction.
Speaker: Others believe that this is more of an anaphylactoid-type reaction, that perhaps many women get amniotic fluid entering their circulation, and only a few have a dramatic response.
Speaker: Most recently, a couple of years ago, there's been interesting papers from a Japanese group
Speaker: suggesting a relationship with C1 esterase inhibitor.
Speaker: They showed a significant reduction in C1 esterase inhibitor in women with amniotic fluid embolism, and the degree of decrease in level correlated with the severity, and they even treated some patients with C1 esterase inhibitor with good outcome.
Speaker: So the final story is certainly not there on the mechanism of the condition.
Speaker: And in terms of incidence, like you said, it's quoted different numbers.
Speaker: There are risk factors that might predispose women to have a higher likelihood in retrospect of having amniotic fluid embolism.
Speaker: But it's very hard to predict who's going to have it and not, right?
Speaker: So I think being able to diagnose it very quickly and think about it or maybe rule out other things is very important.
Speaker: Can you comment on that, Stephen?
Speaker: Yeah, so it's usually a sudden, unexpected, and catastrophic sort of cardiac arrest.
Speaker: And women who survive the initial event, and often there's CPR and a risk of anoxic brain damage, that after the initial event, they may go on to develop ARDS and DIC.
Speaker: But it's a diagnosis essentially of exclusion, so you need to think about other conditions such as pulmonary embolism because we're seeing a lot of older pregnant women these days.
Speaker: You need to think about acute coronary syndromes in a woman who has a sudden cardiac arrest.
Speaker: So a number of other conditions to keep in mind.
Speaker: So it's a diagnosis of exclusion.
Speaker: There are a bunch of tests that are sometimes used.
Speaker: And as I mentioned, the C1 esterase inhibitor is the latest one on the block, but it's still got a lot of way to go before it's an accepted investigation.
Speaker: And in terms of treatment, supporting the cardiovascular system, hemodynamic support, respiratory support are going to be key, and then management of all the organ failures, as with any other patient.
Speaker: Are there any specific treatments that have worked?
Speaker: I know many have been tried, but that we can use for these patients?
Speaker: Yeah, so supportive intubation, ventilation, inotropes.
Speaker: Many people believe that there's a role for steroids, assuming that this is some type of anaphylactoid type reaction.
Speaker: So I think that's something reasonable to do in a young woman who's likely to die.
Speaker: And as I mentioned, there's an interesting association and
Speaker: possibility of treating with a C1 esterase inhibitor, although I haven't seen that done locally.
Speaker: Anything else in terms of any comments of how to manage or organize the teams in smaller hospitals that are not as specialized?
Speaker: Obviously, this requires efforts and decisions with these specific conditions with the obstetrician team, the anesthesia team, the neonatal team.
Speaker: Any comments on how to work that relationships and what we should be thinking of as intensivists?
Speaker: Yeah, I think it's really just a matter of communication and getting to know the people and essentially someone taking charge.
Speaker: And often that is the intensivist who's used to managing sort of catastrophic events.
Speaker: There is a tendency when there are multiple different specialties in the room that no one really takes charge and everyone's assuming everyone else is doing something.
Speaker: So, you know, saying out loud, yeah, I'm in charge obstetrician.
Speaker: Could you help me with this?
Speaker: Could you do that?
Speaker: It also depends on the presence or not of obstetric anaesthetists who are also very experienced with these patients.
Speaker: And I think that's a great point because we also see it in our own world.
Speaker: When you see, quote, teams running cardiac arrest, the ability to take charge and designate specific tasks to other people improves the team's performance significantly because I think we do have a tendency to assume that somebody else is taking charge or taking responsibility and nobody is.
Speaker: Yeah, no, exactly, and I think that is a big problem here.
Speaker: I mean, I find when we have a cardiac arrest in pregnancy, there's just 1,000 people in the room, and it's really not clear who's doing what, and someone really needs to step up.
Speaker: So as we close the part one, I would like to maybe end with some more general questions in terms of your experience in this area.
Speaker: And the first question, Stephen, is could you tell us about a
Speaker: your most instructive failure with this patient population of something that taught you a very important lesson when dealing with these pregnant critically ill patients?
Speaker: Well, not so much a failure, but one issue that does come up occasionally is the question of delivery in a very sick patient.
Speaker: And there's a tendency to think if a pregnant woman is in the ICU, particularly with respiratory failure, doing badly on a ventilator,
Speaker: that maybe delivering her is going to help the situation.
Speaker: In other words, make the pregnancy go away and then we can make things better.
Speaker: And my limited experience with this and a little bit of data is that it's not always helpful.
Speaker: So if the fetus is doing badly because the mother's doing badly and if your local neonatologist feels that they can do better with the fetus in their ICU, then there may be an indication for delivery.
Speaker: But if you're really giving up on the fetus and you're hoping that the delivery is going to dramatically improve the mother, that's not always the case.
Speaker: It may sometimes happen, but often, you know, delivery of a very preterm baby and a hope of making the mother better
Speaker: this may not always be hopeful.
Speaker: So I think that's a very important distinction because avoid that knee-jerk reaction of delivery is going to improve everything and really weigh all the inputs from neonatology, from obstetrics, but also what we're seeing.
Speaker: Like, for example, if somebody has severe ARDS,
Speaker: delivering the baby is not going to change that ARDS at that point, right?
Speaker: Yeah, it's likely not going to change the ARDS, and it's a significant physiological strain on the mother.
Speaker: The delivery is not insignificant.
Speaker: It's an operation, so it potentially could make some aspects worse.
Speaker: And the second question is, what do you think most intensivists get wrong about this patient population?
Speaker: Okay, I think that's an easier question to answer.
Speaker: What they get wrong is assuming that it's complicated and they're very different.
Speaker: And I think if you just think of it, do what you would do in a non-pregnant patient, you're not going to go very wrong.
Speaker: You know, most of the drugs, just about all the drugs you use in the ICU are good for the mother, they're going to be good for the baby.
Speaker: the management of the ventilator, everything else.
Speaker: Don't panic that they're very different.
Speaker: And if you're really stuck and you don't know what to do, do what you would normally do in a non-pregnant patient and things will turn out fine.
Speaker: And I think it speaks to the concept of the well-being of the mother is the best indicator of the well-being of the fetus.
Speaker: And focus on what we would normally do for that sick woman to improve her health, correct?
Speaker: Yeah, I think that's exactly right.
Speaker: So I think this is a great point to stop for part one.
Speaker: Stephen, thank you very much for your time, and we'll have you back for part two where we'll talk about some of the more common conditions that can lead to non-pregnancy specific that can lead patients to the ICU.
Speaker: Okay.
Speaker: Thanks very much.
Speaker: Thanks again for listening to Critical Matters.
Speaker: Make sure to subscribe to this podcast on iTunes or Google Play.
