Lyophilized fibrinogen concentrate (RiaSTAP) is approved by the US Food and Drug Administration for the treatment of congenital hypofibrinogenemia and also may be useful to replace fibrinogen in cases of AFE. In many hospitals, large quantities of fresh frozen plasma are not immediately available; lyophilized fibrinogen concentrate may be especially useful in these settings. Another advantage of fibrinogen concentrate is that large amounts of fibrinogen can be administered in a small volume of intravenous fluid. Fibrinogen concentrate typically is used at a dose of 70 mg/kg of body weight.9,10
Intraoperative red cell salvage occasionally is used in cases of obstetric hemorrhage. In one case report of the use of red cell salvage with leukocyte depletion filtration during treatment of an AFE, acute hypotension developed in the patient after the transfusion of salvaged red cells.11 This case report raises safety concerns about the use of salvaged cells in women with severe AFE.
Related article: 10 practical, evidence-based recommendations for the management of severe postpartum hemorrhage Baha M. Sibai, MD (June 2011)
3. Treat diffuse bleeding and coagulopathy
In addition to the initiation of the massive transfusion protocol, additional treatments that may be helpful in managing the coagulopathy of AFE include tranexamic acid, recombinant factor VIIa (rFVIIa), and exchange transfusion.
AFE is often associated with hyperfibrinolysis, which can cause excessive bleeding.12 Tranexamic acid blocks the lysine binding sites on plasminogen and thereby reduces the lysis of fibrin clots. Clinical trials in patients who have undergone trauma have demonstrated that the administration of tranexamic acid reduces blood loss.13 The dose of tranexamic acid is approximately 10 to 20 mg/kg of body weight, or approximately 1 g.
Controversy exists about the use of rFVIIa to treat the coagulopathy and bleeding caused by AFE. Some authorities believe that rFVIIa is associated with an increased AFE case fatality rate.14 Other authorities believe rFVIIa may be useful in the treatment of AFE coagulopathy, especially when bleeding persists despite aggressive blood and component replacement.”15 The dose of rFVIIa is approximately 90 µg/kg of body weight. rFVIIa is extremely expensive.
Exchange transfusion has been used successfully to treat AFE.16 In women with AFE, exchange transfusion removes circulating cells, cell fragments, and substances that trigger systemic anaphylaxis and coagulopathy, thereby enhancing rapid recovery.
Related article: Act fast when confronted by a coagulopathy postpartum Robert L. Barbieri, MD (Editorial; March 2012)
4. Treat uterine and pelvic bleeding
Obstetrician-gynecologists are experts in the control of uterine and pelvic bleeding. Interventions that commonly are used to control uterine and pelvic bleeding in cases of postpartum hemorrhage, uterine rupture, or placenta accreta also can be applied in cases of AFE with uncontrolled uterine and pelvic bleeding. These techniques include:
- use of uterine compression sutures
- the Bakri balloon
- a uterine tourniquet
- vascular clamps on the ovarian vessels.17,18
In many cases of AFE, total or supracervical hysterectomy is necessary to control uterine bleeding. Uterine artery embolization, if available, has been reported to be helpful in select cases. However, many women with AFE are too unstable to survive transfer to an interventional radiology suite. Additional interventions to control bleeding include hypogastric artery ligation, infrarenal aortic compression, and pelvic packing.
Cross-clamping the aorta below the renal vessels can reduce blood flow to the pelvis and provide time for cardiopulmonary and volume resuscitation. Alternatively, placing pressure on the infrarenal aorta with a sponge or directly by hand can help reduce blood flow to the pelvis.19
In many cases of AFE, pelvic hemorrhage is difficult to control. Even if surgical pedicles are ligated securely, the coagulopathy of AFE may cause persistent oozing from areas of minor tissue trauma. Uncontrolled blood loss can be a proximate cause of death in women with AFE. All written protocols for responding to an AFE should include a plan to use pelvic packing for patients in whom standard operative procedures do not produce adequate control of bleeding. A “mushroom,” “parachute,” or “umbrella” pack has been reported to help stabilize the severely ill patient with pelvic bleeding and permit effective resuscitation and blood product replacement.20
Related articles:
A stitch in time: The B-Lynch, Hayman and Pereira uterine compression sutures Robert L. Barbieri, MD (Editorial, December 2012)
Have you made the best use of the Bakri balloon in PPH? Robert L. Barbieri, MD (Editorial, July 2011)
5. Consider extracorporeal lung and heart support
In many cases of AFE, both lung and cardiac function are severely compromised. Both veno-arterial extracorporeal membrane oxygenation (VA-ECMO) and full cardiopulmonary bypass provide support for the failing lung and heart. Based on a small number of case reports, extracorporeal lung and heart support appear to be useful in the treatment of AFE.21–26 Using the Seldinger technique,27 it is technically feasible to rapidly access a major vein and artery to provide the input and output ports for VA-ECMO. Unlike the cardiopulmonary bypass pump, the VA-ECMO pump does not have a reservoir that needs to be primed with blood and is smaller and more portable. To provide a patient with VA-ECMO or cardiopulmonary bypass, a cardiac interventionist and a perfusionist must be available. Extracorporeal lung and heart support require heparinization of the patient’s blood, which may result in increased bleeding. Both VA-ECMO and cardiopulmonary bypass, along with the diseases for which they are used, may cause renal dysfunction, neurologic injury, and infection.28
