Amniotic Fluid Embolism Workup

  • Author: Lisa E Moore, MD, FACOG; Chief Editor: Carl V Smith, MD   more...
 
Updated: Jan 13, 2012
 

Laboratory Studies

  • Arterial blood gas (ABG) levels: Expect changes consistent with hypoxia/hypoxemia.
    • Decreased pH levels (reference range = 7.40-7.45)
    • Decreased PO2 levels (reference range = 104-108 mm Hg)
    • Increased PCO2 levels (reference range = 27-32 mm Hg)
    • Base excess increased
  • CBC with platelets
    • Hemoglobin and hematocrit levels should be within reference ranges.
    • Thrombocytopenia is rare. If platelets are less than 20,000/µL, or if bleeding occurs and platelets are 20,000-50,000/µL, transfuse platelets at 1-3 U/10 kg/d.
  • Prothrombin time and activated partial thromboplastin time
    • Prothrombin time (PT) is prolonged because clotting factors are used up. Values are institution specific, but intervention is indicated when the PT is 1.5 times the control value. Administer fresh frozen plasma (FFP) to normalize the PT.
    • Activated partial thromboplastin time (aPTT) may be within reference ranges or shortened.
  • If fibrinogen level is less than 100 mg/dL, administer cryoprecipitate. Each unit of cryoprecipitate raises the fibrinogen level 10 mg/dL.
  • Blood type and screen in anticipation of the requirement for a transfusion.
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Imaging Studies

Chest radiograph posteroanterior and lateral findings are usually nonspecific, but evidence of pulmonary edema may be observed.

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Other Tests

A 12-lead ECG may show tachycardia, ST segment and T-wave changes, and findings consistent with right ventricle strain.

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Procedures

  • Arterial line to accurately measure blood pressure and to obtain ABG readings
  • Pulmonary artery catheter to monitor wedge pressure, cardiac output, oxygenation, and systemic pressures
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Histologic Findings

On autopsy, blood vessels in the lungs may show evidence of fetal debris (eg, squamous cells, vernix, mucin).

Aguilera et al[14] reported fetal epithelial squamous cells obstructing 80% of pulmonary capillaries and fetal epithelial squamous cells in the alveoli on autopsy. A blood sample from a central venous catheter also showed fetal squames.

Marcus et al[5] found focal interstitial hemorrhages in the kidneys, the left ventricle, and the interventricular septum. Alcian blue periodic acid-Schiff (PAS) stain was positive for mucin in the vasculature and oil red O stain for lipid was positive in the lungs.

Hankins and colleagues[15] reported on goats injected with fresh amniotic fluid (n=8), filtered amniotic fluid (n=14), and meconium-stained fluid with solid debris (n=7). The animals were euthanized 3 hours after the procedure and samples of the lungs were taken. Amniotic fluid debris was found in 7 out of 7 of the meconium-stained group, 2 out of 8 of the fresh fluid group, and 1 out of 14 of the filtered group. Hankins et al concluded that, in this model, histopathologic confirmation of AFE was unreliable except in cases involving meconium-stained fluid.

Kobayashi et al[16] used antibody TKH-2, which reacts with meconium and the mucin derived from amniotic fluid (glycoprotein) to stain the lung tissue of women with AFE. TKH-2 immunostaining appears to be a sensitive method of detecting mucin in the lungs of women suspected of having an amniotic fluid embolus.

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Contributor Information and Disclosures
Author

Lisa E Moore, MD, FACOG  Assistant Professor, Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine, University of New Mexico Health Sciences Center

Lisa E Moore, MD, FACOG is a member of the following medical societies: American College of Obstetricians and Gynecologists, American Medical Association, and Society for Maternal-Fetal Medicine

Disclosure: Nothing to disclose.

Specialty Editor Board

John J Kavanagh Jr  MD, Chief, Professor, Department of Internal Medicine, Section of Gynecological and Medical Therapeutics, MD Anderson Cancer Center, University of Texas Medical School at Houston

John J Kavanagh Jr is a member of the following medical societies: American Association for Cancer Research, American Association for the Advancement of Science, American Association for the History of Medicine, American College of Physicians, American Federation for Medical Research, American Medical Association, Society of Gynecologist Oncologists, Southern Medical Association, and Texas Medical Association

Disclosure: Nothing to disclose.

Francisco Talavera, PharmD, PhD  Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Medscape Salary Employment

A David Barnes, MD, PhD, MPH, FACOG  Consulting Staff, Department of Obstetrics and Gynecology, Mammoth Hospital (Mammoth Lakes, California), Pioneer Valley Hospital (Salt Lake City, Utah), Warren General Hospital (Warren, Pennsylvania), and Mountain West Hospital (Tooele, Utah)

A David Barnes, MD, PhD, MPH, FACOG is a member of the following medical societies: American College of Forensic Examiners, American College of Obstetricians and Gynecologists, American Medical Association, Association of Military Surgeons of the US, and Utah Medical Association

Disclosure: Nothing to disclose.

Frederick B Gaupp, MD  Consulting Staff, Department of Family Practice, Hancock Medical Center

Frederick B Gaupp, MD is a member of the following medical societies: American Academy of Family Physicians

Disclosure: Nothing to disclose.

Chief Editor

Carl V Smith, MD  The Distinguished Chris J and Marie A Olson Chair of Obstetrics and Gynecology, Professor, Department of Obstetrics and Gynecology, Senior Associate Dean for Clinical Affairs, University of Nebraska Medical Center

Carl V Smith, MD is a member of the following medical societies: American College of Obstetricians and Gynecologists, American Institute of Ultrasound in Medicine, Association of Professors of Gynecology and Obstetrics, Central Association of Obstetricians and Gynecologists, Council of University Chairs of Obstetrics and Gynecology, Nebraska Medical Association, and Society for Maternal-Fetal Medicine

Disclosure: Nothing to disclose.

References

  1. Clark SL, Hankins GD, Dudley DA, et al. Amniotic fluid embolism: analysis of the national registry. Am J Obstet Gynecol. Apr 1995;172(4 Pt 1):1158-67; discussion 1167-9. [Medline].

  2. Clark SL, Pavlova Z, Greenspoon J, et al. Squamous cells in the maternal pulmonary circulation. Am J Obstet Gynecol. Jan 1986;154(1):104-6. [Medline].

  3. Benson MD, Kobayashi H, Silver RK, et al. Immunologic studies in presumed amniotic fluid embolism. Obstet Gynecol. Apr 2001;97(4):510-4. [Medline].

  4. Farrar SC, Gherman RB. Serum tryptase analysis in a woman with amniotic fluid embolism. A case report. J Reprod Med. Oct 2001;46(10):926-8. [Medline].

  5. Marcus BJ, Collins KA, Harley RA. Ancillary studies in amniotic fluid embolism: a case report and review of the literature. Am J Forensic Med Pathol. Mar 2005;26(1):92-5. [Medline].

  6. Gilbert WM, Danielsen B. Amniotic fluid embolism: decreased mortality in a population-based study. Obstet Gynecol. Jun 1999;93(6):973-7. [Medline].

  7. Tuffnell DJ. United kingdom amniotic fluid embolism register. BJOG. Dec 2005;112(12):1625-9. [Medline].

  8. Stein PD, Matta F, Yaekoub AY. Incidence of amniotic fluid embolism: relation to cesarean section and to age. J Womens Health (Larchmt). Mar 2009;18(3):327-9. [Medline].

  9. O'Shea A, Eappen S. Amniotic fluid embolism. Int Anesthesiol Clin. 2007;45(1):17-28. [Medline].

  10. Kramer MS, Rouleau J, Baskett TF, Joseph KS,. Amniotic-fluid embolism and medical induction of labour: a retrospective, population-based cohort study. Lancet. Oct 21 2006;368(9545):1444-8. [Medline].

  11. Knight M, Tuffnell D, Brocklehurst P, Spark P, Kurinczuk JJ. Incidence and risk factors for amniotic-fluid embolism. Obstet Gynecol. May 2010;115(5):910-7. [Medline].

  12. Benson MD. Current concepts of immunology and diagnosis in amniotic fluid embolism. Clin Dev Immunol. 2012;2012:946576. [Medline]. [Full Text].

  13. Clark SL. Amniotic fluid embolism. Clin Obstet Gynecol. Jun 2010;53(2):322-8. [Medline].

  14. Aguilera LG, Fernandez C, Plaza A, et al. Fatal amniotic fluid embolism diagnosed histologically. Acta Anaesthesiol Scand. Mar 2002;46(3):334-7. [Medline].

  15. Hankins GD, Snyder R, Dinh T, et al. Documentation of amniotic fluid embolism via lung histopathology. Fact or fiction?. J Reprod Med. Dec 2002;47(12):1021-4. [Medline].

  16. Kobayashi H, Ohi H, Terao T. A simple, noninvasive, sensitive method for diagnosis of amniotic fluid embolism by monoclonal antibody TKH-2 that recognizes NeuAc alpha 2-6GalNAc. Am J Obstet Gynecol. Mar 1993;168(3 Pt 1):848-53. [Medline].

  17. Lim Y, Loo CC, Chia V, Fun W. Recombinant factor VIIa after amniotic fluid embolism and disseminated intravascular coagulopathy. Int J Gynaecol Obstet. Nov 2004;87(2):178-9. [Medline].

  18. 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 2001;40(9):945-7. [Medline].

  19. 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 2000;183(2):496-7. [Medline].

  20. Goldszmidt E, Davies S. Two cases of hemorrhage secondary to amniotic fluid embolus managed with uterine artery embolization. Can J Anaesth. Nov 2003;50(9):917-21. [Medline].

 
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