1. Embolism during Pregnancy
Robert Nichols, DO
Embolism during Pregnancy

2. Embolism Pulmonary Embolism Venous Air Embolism
Amniotic Fluid embolism

3. Embolism One of the leading causes of maternal mortality
Non-cardiovascular diseases, 15.3%.
Cardiovascular diseases, 14.7%.
Infection or sepsis, 12.7%.
Hemorrhage, 11.3%.
Cardiomyopathy, 10.8%.
Thrombotic pulmonary embolism, 9.0%.
Hypertensive disorders of pregnancy, 7.6%.
Cerebrovascular accidents, 6.5%.
Amniotic fluid embolism, 5.7%.
Anesthesia complications, 0.2%.

4. Pulmonary Embolism Difficult diagnosis and management
2 patients at risk
Overdiagnosis results in unnecessary and often dangerous treatments to both patients
Usual imaging modalities must be considered with developing fetus

5. Pulmonary Embolism Higher risk 2/2 Virchows triad
Hypercoagulability
Vascular damage
Venous stasis
DVT occurs approximately 3x more frequently than PE
DVT occurs on left leg in 85% of cases
Likely due to compression of iliac vein by iliac artery and gravid uterus
Isolated pelvic DVT is also much more common in parturients

6. Pulmonary Embolism ACOG guidelines to diagnosis
Diagnosis often difficult
D-Dimer unreliable in pregnant patients
Risk of radiation exposure in pregnancy must be considered

7. Treatment LMWH is treatment of choice in early pregnancy
Can be given as outpatient
Do not cross placenta and are is not secreted in breastmilk
1mg/kg q12
IV unfractionated heparin preferred near delivery and in renal failure
Able to reverse urgently if needed
Also does not cross placenta or go into breastmilk
Bolus 80u/kg followed by 18u/kg/h, titrated to achieve therapeutic aPTT
If SC initial dose is 17,500 units then titrated to aPTT
Thrombolytic drugs appropriate in hemodynamically unstable or hypoxic
Fetal loss vs. maternal death
Warfarin teratogenic and generally contraindicated in pregnant patient

8. Venous Air Embolism
Entrapment of air or medical gases into venous system causing symptoms and signs of pulmonary vessel obstruction
1% of maternal deaths
Incidence varies WIDELY depending on the source
Depends on surgical position, diagnostic tools

10. Pathophysiology
Vascular access and gradient between injury site and right heart must be present for VAE to occur
Determined by rate, volume, duration, patient position, type of gas
Pulmonary vessels can filter most air emboli from venous circulation
Larger emboli can cause a variety of symptoms

11. Risk Factors VAE Trendelenburg position Placental abruption
Placenta previa
Exteriorization of uterus
Manual placental extraction
Severe preeclampsia
Antepartum hemorrhage
hypovolemia

12. Diagnosis Know clinical signs and symptoms
May manifest as chest tightness or short breath with or without hypotension or decreased oxygen saturation in conscious patients
Variety of diagnositic tools

13. Treatment Inform Surgeon Adequate hydration Prevent further gas entry
Flood surgical field
Remove origin of gas entry
Increase right atrial pressure and trap air in right atrium
Reverse Trendelenburg when possible
Left lateral recumbent position
Discontinue N2O and ventilate with 100% oxygen
Attempt to aspirate air through central line when appropriate
Resuscitate
Fluid administration
Inotropes, vasopressor, pulmonary vasodilators
CPR if necessary
Hyperbaric oxygen when appropriate

14. Amniotic fluid embolism
5.7% of pregnancy related deaths in United States in
Poorly understood
Diagnosis traditionally made at autopsy when fetal squamous cells are found in pulmonary circulation
Diagnosis of exclusion
Mortality of AFE approaches 80%
50% die within the first hour of onset of symotoms

15. AFE Pathophysiology
Theorized that amniotic fluid and cells enter circulation and trigger anaphylactic reaction
Fetal material not always found in patients with AFE and fetal material found in patients who did not trigger anaphylaxis
Currently believed that fluid or some other substance enters maternal circulation and triggers anaphylactic reaction OR activates complement cascade OR both.
Occurs in 2 phases
1. pulmonary artery vasospasm with pulmonary hypertension and elevated right ventricular pressure which causes hypoxia. Hypoxia causes myocardial and pulmonary capillary damage, left heart failure and ARDS.
2. Those who survive phase 1 have hemorrhagic phase with massive hemorrhage with uterine atony and DIC; however, fatal consumptive coagulopathy may be the initial presentation

16. AFE risk factors Multiparity Advanced maternal age Male fetus Trauma
Abruption
Previa
Non-Hispanic black women have more than 2x risk of AFE
Women with cerebrovascular disease have 25x risk
Cardiac disease have 70x risk!

17. Treatment Supportive Early resuscitation
Pulmonary edema common – fluid input and output must be closely monitored
Left heart failure treated with ionotropes
Case reports show successful outcomes with hemodialysis with plasmapheresis and ECMO with intra-aortic balloon pump
DIC treated with blood components. Consider activated factor VIIa for severe hemorrhage
2 cases report success with bilateral uterine artery embolization

18. References
Panting-Kemp A, Geller SE, Nguyen T, Simonson L, Nuwayhid B, Castro L. Maternal deaths in an urban perinatal network, Am J Obstet Gynecol ;183:
Chan WS, Ray JG, Murray S, Coady GE, Coates G, Ginsberg JS. Suspected pulmonary embolism in pregnancy: clinical presentation, results of lung scanning, and subsequent maternal and pediatric outcomes. Arch Intern Med. 2002;162:  
Einstein AJ, Henzlova MJ, Rajagopalan S. Estimating risk of cancer associated with radiation exposure from 64-slice computed tomography coronary angiography. JAMA ;298:
Kim, Chang Seok et al. “Venous Air Embolism during Surgery, Especially Cesarean Delivery.” Journal of Korean Medical Science 23.5 (2008): 753–761.PMC. Web. 28 Mar
Lim Y, Loo CC, Chia V, Fun W. Recombinant factor VIIa after amniotic fluid embolism and disseminated intravascular coagulopathy. Int J Gynaecol Obstet Nov. 87(2):178-9.
Kaneko Y, Ogihara T, Tajima H, Mochimaru F. Continuous hemodiafiltration for disseminated intravascular coagulation and shock due to amniotic fluid embolism: report of a dramatic response. Intern Med Sep. 40(9):945-7.
Hsieh YY, Chang CC, Li PC, Tsai HD, Tsai CH. Successful application of extracorporeal membrane oxygenation and intra-aortic balloon counterpulsation as lifesaving therapy for a patient with amniotic fluid embolism. Am J Obstet Gynecol Aug. 183(2):496-7.
Goldszmidt E, Davies S. Two cases of hemorrhage secondary to amniotic fluid embolus managed with uterine artery embolization. Can J Anaesth Nov. 50(9):  
Clark SL. Amniotic fluid embolism. Clin Obstet Gynecol Jun. 53(2):322-8. 
Fong A, Chau CT, Pan D, et al. Amniotic fluid embolism: antepartum, intrapartum and demographic factors. J Matern Fetal Neonatal Med Jun  
Stein PD, Matta F, Yaekoub AY. Incidence of amniotic fluid embolism: relation to cesarean section and to age. J Womens Health (Larchmt) Mar. 18(3):327-9.