We discuss the clinical presentation and management of AFE with guests Dr. Stephanie Martin (Twitter: @OBCriticalCare, Instagram: @criticalcareob), medical director for Clinical Concepts in Obstetrics and a Maternal Fetal Medicine specialist in Scottsdale, Arizona with expertise in critical care obstetrics. She is also co-host of the Critical Care Obstetrics podcast. We’re also joined for a patient perspective by Miranda Klassen (@afefoundation), Executive Director of the AFE Foundation, and her husband Bryce Klassen, CCRN, ICU Supervisor at Scripps Memorial Hospital Encinitas.
AFE is poorly understood but is probably caused by exposure of amniotic fluid (skin cells, hair, vernix, etc) to maternal blood, causing a severe inflammatory reaction. Although it may contribute, it is probably not mainly due to obstructive shock, as seen in pulmonary embolism.
AFE is rare. Some clinicians will go an entire career without seeing it. However, it certainly happens and has tremendous consequences when it does.
As a rule, ACLS care is the same for pregnant women. The main exception is that if ROSC is not obtained immediately, you must perform a resuscitative Caesarean section within the first 4 minutes, aiming to have the baby delivered within 5. Without this, the chances of recovering the mother are slim: the gravid uterus interferes with compressions, compresses the IVC, and causes other problems. Achieving this in non-obstetric areas requires a carefully thought-out process. Time must not be wasted transporting the patient elsewhere. The only equipment absolutely required is a scalpel, although this too can be hard to find if you haven’t optimized your process. In short, if you have a pregnant woman in your ICU, figure out now what you’re going to do now if she codes.
Due to the logistical challenges, most of these resuscitative C-sections are actually done in 6-15 minutes. This is not the goal.
During CPR, the gravid uterus should be manually displaced to one side, preferably the left. (It is no longer recommended to tilt the patient laterally, since this interferes with compressions.)
AFE is rare, but with excellent care it is survivable.
Bleeding post C-section is usually not significant. The abdomen can be left open, and can even be used for aortic access to check for the pulse, or occlude the aorta (either manually or by cross-clamp).
A normal fibrinogen level in a pregnant or immediately post-partum female is elevated (often in the ~600s), so a “normal” level should be considered low. Use this to follow DIC. Bleeding and clotting may both occur.
Although pregnant women have a subtle physiologic hemodilution, their normal hemoglobin should not drop below 11, so for our purposes, anemia still denotes anemia.
Resuscitating the immediately post-partum woman should not mean great confusion about safe medications. Use whatever is necessary to save her life. Any impacts on breastmilk can be managed by pumping and either saving or dumping it as appropriate.
A compensated respiratory alkalosis via hyperventilation should be expected during pregnancy (the mother must have a lower PCO2 than the fetus to create a gradient for fetal ventilation). This persists post-partum, so it’s probably appropriate to aim to maintain this by increasing minute ventilation, even although it’s likely not as critical since there’s no longer a fetus to support.
The most important post-partum care after an emergency like this remains supportive critical care. Eventually the mother can be transferred to a post-partum obstetric unit, but these are not high acuity floors (with nurse:patient ratios as high as 8:1) and this needs not be rushed. OB staff can come to the ICU to assist and educate as needed.
If you have a suspected AFE, call the AFE Foundation 24/7 (307-363-2337) for advice and to coordinate collection of specimens, which must be done promptly and is badly needed to improve our understanding of this disease.
Amniotic fluid embolism: principles of early clinical management. Pacheco, Luis D, Klassen, M., et. al. American Journal of Obstetrics & Gynecology.
Society for Maternal-Fetal Medicine (SMFM). Pacheco LD, Saade G, et al. Amniotic fluid embolism: diagnosis and management. Am J Obstet Gynecol 2016; 215:B16.
Stafford, IA, Moaddab, A, Dildy, GA (2019) Evaluation of proposed criteria for research reporting of amniotic fluid embolism. AJOG, 220, 285-287.
Combs CA, Montgomery DM, Toner LE, Dildy GA, Patient Safety and Quality Committee, Society for Maternal-Fetal Medicine, Society for Maternal-Fetal Medicine Special Statement: Checklist for initial management of amniotic fluid embolism, American Journal of Obstetrics
Amniotic fluid embolism: Pathophysiology from the perspective of pathology. Tamura N, Farhana M, Oda T, Itoh H, Kanayama N. J Obstet Gynaecol Res. 2017;43(4):627. Epub 2017 Feb 11.
Kiranpreet, K., Bhardwaj, M, Kumar, P., Singhai, S., Singh, T., & Hooda, S. (2016). Amniotic fluid embolism. J Anesthesiol Clin Pharmacol, 32(2), 153-159.
Zelop CM, Einav S, Mhyre JM, Lipman SS, Arafeh J, Shaw RE, Edelson DP, Jeejeebhoy FM; American Heart Association’s Get With the Guidelines-Resuscitation Investigators. Characteristics and outcomes of maternal cardiac arrest: A descriptive analysis of Get with the guidelines data. Resuscitation. 2018 Nov;132:17-20. doi: 10.1016/j.resuscitation.2018.08.029. Epub 2018 Aug 28. PMID: 30170022.
A look at rehabilitation and mobility in the critically ill, from the perspective of our skilled therapists—with Heidi Engel, PT, DPT of UC San Francisco, long-term provider of acute care therapy, researcher in ICU rehabilitation, and founding member of the SCCM’s ICU Liberation program.
Tolerance of pressure support ventilation is often a good marker that a patient is ready to start meaningful PT. Before that, the harm may exceed the benefit, unless there’s a specific reason why activity may help move them along, such as attenuating delirium and agitation and improving tolerance of the ET tube.
The most common complaints and stressors of ICU patients are: feeling thirsty, feeling traumatized and afraid, the inability to communicate, and feeling “air hungry” due to the strange mechanics of mechanical ventilation and other respiratory modalities.
In many cases, rehab will require convincing patients to get over an initial hump. Breathing, strength, and discomfort may initially be a challenge but will improve with activity.
You may need to choose priorities: do you want to push vent liberation or mobility today?
Bring the light during daytime hours to improve the circadian rhythm, but direct fluorescent lights are harsh and can encourage closed eyes. Natural, indirect light is better.
Although PT and OT have complementary roles, they will sometimes try to see patients together, which can have downsides by underemphasizing the unique aspects of each role, reducing total rehab time, and relegating one skilled therapist to acting as merely a set of hands.
The presence of any sedation, even “gentle” agents like precedex, creates an obstacle to effective PT.
Getting patients up to a chair helps with agorophobia by changing their perspective from their tiny bed-shaped home.
Heidi’s rehab process
Check the RASS and CAM-ICU scores
Explain to patient the importance of the endotracheal tube and not touching it. Bring all equipment to the side of the bed with the ventilator.
Perform some gastroc/hamstring stretching to initiate mobility and help wake the patient up
Ask them to follow commands, such as: push! Can they follow? Do the vent and vitals remain okay?
Sit them up at edge of bed, arrange equipment. Observe head control, trunk control, breathing, vitals, orthostasis, etc.
bring a big mobility device, see if they can stand.
While they’re up, use the opportunity to clean the linen, wash their face, comb their hair, clean their posterior.
COVID is making it harder, often just for practical reasons: PPE limiting mobility, noise from filters and masks, families not present, weird autonomic and orthostatic issues… all far more time consuming. However, they do get better and many times do very well, sometimes even recovering faster than similar non-COVID patients. Omicron has not been as bad.
Dedicated therapy teams for the ICU add cost, but cost analyses have shown the benefit (in terms of reducing length of stay and other expenses) to actually result in net cost savings.
In-bed, non-weight-bearing activities such as passive range of movement exercise is perhaps better than nothing, but is nowhere near as useful as weightbearing activity out of bed, and has not shown the same clinical benefits in the literature. Every day of out-of-bed activity may pay back several fewer days of rehab down the road.
The hows, whys, logistics, and applications of focused, bedside transesophageal echocardiography performed by critical care and EM providers, with Felipe Teran, assistant professor of emergency medicine at Weill Cornell and director of the Resuscitative TEE Project.
As a rule, resuscitative TEE is performed in patients with a secured airway.
TEE views are not unlike TTE views, just at a different angle (often backwards/upside down down). The technical skills are very similar, and skilled TTE users will find the learning curve short. There are actually fewer probe manipulations (in and out, left and right, and Omniplane rotation, along with some less-used ones like flexion/extension).
The same questions you’d typically ask with TTE can be asked with TEE: is there tamponade? is there cardiogenic shock? is there RV failure? is there hypovolemia? These can be answered even in patients with technically-difficult surface windows.
Some questions hard to answer with TTE can be answered with TEE, such as obtaining reliable RV inflow-outflow views and reliable valve assessments.
Some new questions can be answered with TEE alone: is there aortic dissection? are catheters and wires (ECMO, Impella, pacing wires, etc) optimally placed?
TEE has specific applications in cardiac arrest: are chest compressions optimally positioned on the chest? What is the rhythm? It provides monitoring much more continuous than intermittent TTEs, since it can be left in place.
In an ideal world, resuscitative TEE would be handled very much like TTE, and performed in a similar way—not restricted to some small group of “superusers” or for very rare cases.
When implemented by trained users in appropriately-selected cases (e.g. in shock with inadequate transthoracic windows), it impacts care virtually 100% of the time.
Brandon and Bryan talk about the practicalities of communication, collaboration, and compromise in a surgical ICU, when the surgical and critical care teams are both involved, one is the “primary” team on paper, but everyone needs to be heard.