**3.1. Preoperative optimization**

In the United States alone, the rate doubled from 5.4 in 10,000 deliveries to 11.9 in 10,000 over a period of 6 years [2]. The most severe form, placenta percreta, in which chorionic villi penetrate through the uterine wall and into adjacent organs, has increased 50-fold in the last 50 years [3]. Women with multiple prior cesarean deliveries are at greatest risk for MAP. The risk of MAP in patients after one, two, or three prior cesarean deliveries increases 2.9, 4.6 and 12.6-fold, respectively [4]. Additional risk factors include prior surgical injury to the myometrium,

The potential consequences of obstetric hemorrhage are most dire in women who refuse, or cannot receive, blood products. For example, the maternal mortality ratio (MMR) due to major obstetric hemorrhage in Jehovah's Witnesses was 68 per 100,000 live births in one study; 130 times that of the general population [5]. Furthermore, in low resource settings, where blood products are not readily available, the MMR can be up to 645 per 100,000 live births [6]. Obstetric hemorrhage accounts for up to 42% of maternal deaths in low resource settings [7]. With this in mind, new strategies for obstetric hemorrhage control are essential for improving transfusion-free survival. Resuscitative endovascular balloon occlusion of the aorta (REBOA) is an emerging, minimallyinvasive technique to control non-compressible hemorrhage. Although initially developed for the management of traumatic hemorrhage, REBOA has been gaining popularity for the control of non-traumatic hemorrhage. Early reports of REBOA use in obstetric hemorrhage indicate that the approach reduces blood loss, improves maternal outcomes, and decreases rates of hysterectomy compared to traditional techniques, such as uterine balloon tamponade, and hypogastric or uterine artery occlusion [8–10]. This review describes the potential applications of REBOA for control of obstetric hemorrhage in high-risk obstetric surgery for MAP. High-quality evidence to inform management of obstetric hemorrhage when transfusion is not an option is generally lacking. Small numbers of patients, clinical heterogeneity, and ethical principles preclude against randomized studies, so most data are drawn from case series and case reports, as well as from physiological principles and expert opinions. REBOA is a growing modality with novel applications, as well as technical and technological improvements that are continually evolving. The application of REBOA to obstetric hemorrhage is in its infancy, thus comparative data and long-term follow-up are lacking. While this may limit the strength of any generalizations that can be drawn from the literature, this review aims to provide a framework for use of REBOA in obstetric care in this challenging circumstance.

Approximately 60% of women with MAP will experience significant morbidity, including blood transfusion, urologic injury, infection, intensive care unit admission, and readmission. A 15% of obstetric hemorrhage requiring blood transfusion are due to MAP [11]. The majority of patients with MAP will undergo invasive procedures, have extensive blood loss and require massive blood transfusion [2, 11]. A 90% of patients with placenta percreta who undergo cesarean hysterectomy will require blood transfusion due to intraoperative blood losses greater than three liters, with median transfusion of 7 units of red blood cells [12, 13].

including dilation and curettage, and advanced maternal age.

96 Placenta

**2. Demographics of high-risk patients**

During the first prenatal visit, willingness to accept blood products should be addressed and alternatives to transfusion discussed. For patients who indicate that they would not accept blood transfusion, providers should investigate which, if any, blood products or alternatives may be acceptable in the case of an emergency. In addition to establishing patient capacity, a thorough discussion of the potential risks and benefits of transfusion is necessary. This discussion with patients should be performed privately and confidentially. It must be free of coercion and judgment from outside parties [14, 15]. In circumstances of a religious basis for blood refusal, patients frequently consult with religious leaders, family and friends prior to making a decision, but the final decision must rest in the hands of the patient herself. These discussions must be clearly documented in the medical record.

Preoperative optimization of hemoglobin by treating underlying anemia is ideal. Many patients who do not accept blood will accept other methods to improve hemoglobin levels. Iron, vitamin B12, folate and recombinant erythropoietin can be used preoperatively [14, 15]. Intravenous iron is preferred over oral preparations because of faster and more reliable increases in hemoglobin. Recombinant erythropoietin can optimize hemoglobin both preoperatively and postoperatively. However, there are no clear guidelines on optimal dosing. While studies suggest erythropoietin is safe to use in pregnancy, it can increase the risk of venous thromboembolism (VTE), which may exacerbate an already hypercoagulable state [16]. Consultation and coordination with a hematologist should be considered.

As the pregnancy advances, careful monitoring of the placenta is imperative to understanding the extent of MAP. A plan for delivery in an appropriately-resourced setting is crucial. Advanced directives should be established, with legal counsel as necessary. A multidisciplinary effort should be assembled to discuss the optimal approach to planned and unplanned delivery. Ideally, this team should include members of the surgical obstetric team (which may include gynecologic oncology), maternal fetal medicine, neonatology, anesthesia, and in-house emergency surgery providers (such as trauma or vascular surgery) as indicated. Working with risk management, social services, and the ethics board may be necessary to optimize outcomes in these complex, high-risk situations.

### **3.2. Intraoperative adjuncts**

Minimization of intraoperative blood loss and optimization of anemia tolerance improves outcomes. While the surgical team focuses on hemostatic techniques to decrease blood loss, the anesthesia team can also support this goal. Patient positioning and ventilation mode can alter venous congestion, venous preload, cardiac output and peripheral vascular resistance. Normothermia aids in hemostasis. Additionally, intentional hypotension after delivery of the fetus may help minimize blood loss. A more detailed description of the anesthetic management of patients with MAP is beyond the scope of this article and has been covered elsewhere [16].

successful in 78.4% of cases, this treatment carries an increased risk of postoperative sepsis and hemorrhage, which could necessitate emergent hysterectomy, further increasing the risk of more serious complications [25, 27]. In patients where the placenta is left in place, a risk of bleeding and infection exists for up to 5 months [28]. The risks of this approach may be

Management of High-Risk Obstetrical Patients with Morbidly Adherent Placenta in the Age…

http://dx.doi.org/10.5772/intechopen.78753

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Traditional vascular methods of hemorrhage control during cesarean hysterectomy include intraoperative hypogastric artery ligation, uterine artery balloon occlusion with or without embolization, and temporary balloon occlusion of the hypogastric arteries. These methods have come under criticism after studies failed to demonstrate a significant reduction in blood loss or transfusion volumes compared to cesarean hysterectomy without these measures [29–31]. Ligation of the hypogastric arteries theoretically reduces pulse pressure to the uterus; however, it is successful in reducing operative blood loss in fewer than 50% of cases. Furthermore, ligation is estimated to be even less useful in MAP involving the bladder [32]. The literature regarding prophylactic intravascular hypogastric balloon occlusion during cesarean hysterectomy with MAP is mixed. Some studies suggest this technique reduces intraoperative blood loss and transfusion requirements [33], but others have found no difference in blood loss even in combination with uterine artery embolization, concluding that prophylactic intravascular balloon catheters yield no significant benefit [29–31]. These disparate findings are most likely explained by the persistent proximal collateral circulation to the uterus which contributes to

Aortic cross-clamping can aid in hemorrhage control when hypogastric artery occlusion is insufficient [36]. Once surgical hemostasis has been maximized, damage control techniques such as packing and temporary abdominal closure may be useful in cases of disseminated

Postoperative management centers around reducing further hemorrhage and providing supportive care for profound anemia. Intensive care monitoring may be required. Hematology consultation may provide guidance regarding hemoglobin optimization with use of high dose erythropoietin, intravenous iron, and other adjuncts [16]. Using pediatric blood collection tubes and avoiding unnecessary lab draws are helpful strategies. In extreme cases, measures to reduce oxygen demand and increase oxygen delivery, including intubation, sedation, and hyperbaric oxygen, may be beneficial [16, 37]. Finally, providers must weigh the risks and

REBOA is a catheter-based alternative to aortic cross clamping that can be used proactively prior to hemodynamic collapse and even prior to anticipated hemorrhage. Endoluminal aortic

benefits of anticoagulation causing increased bleeding against the risk of VTE.

**4.1. Resuscitative endovascular balloon occlusion of the aorta (REBOA)**

prohibitively high in patients who cannot accept blood transfusion [25].

venous hemorrhage during surgery [34, 35].

**3.4. Management of postoperative anemia**

**4. Novel hemorrhage mitigation strategies**

intravascular coagulation.

Several other methods can improve physiologic tolerance of anemia. Intraoperative volume expansion can be achieved through acute normovolemic hemodilution (ANH). With ANH, venous blood is removed into citrated bags at the start of surgery. The blood remains in a closed circuit with the patient throughout surgery. Crystalloid is administered to increase blood volume until hemorrhage is controlled, at which point ANH blood is transfused [17, 18]. Survival after more than five liters of blood loss has been documented in Jehovah's Witness patients with placenta percreta using ANH and cell salvage [19].

There is variability in the products that Jehovah's Witnesses will and will not accept [15]. Generally, whole blood products are prohibited, but some patients will accept fractions, such as hemoglobin, albumin, cryoprecipitate, clotting factors and platelets. A study of Jehovah's Witness patients found that, although most would decline conventional blood products, 76% would accept other blood components [20]. Most will accept crystalloid, colloid, recombinant factor VIIa (rFVIIa), factor VIII (FVIII), fibrinogen, tranexamic acid (TXA), and artificial blood substitutes [14, 15], but use of individual blood components alone may have limitations. Cryoprecipitate, containing FVIII, factor XIII (FXIII), von Willebrand factor (vWF) and fibrinogen, can be used in a postpartum hemorrhage to reduce risk of coagulopathy due to hypofibrinogenemia. However, it is not a substitute for plasma due to the lack of other coagulation factors. There is limited evidence that rFVIIa is helpful in refractory postpartum hemorrhage [21]. Finally, TXA is an antifibrinolytic agent that can be an adjunct for hemorrhage management. A Cochrane review found that TXA decreases blood loss and hemorrhage in both vaginal and cesarean deliveries [22]. The WOMAN trial found that administering TXA for postpartum hemorrhage within 3 hours of delivery decreased the rate of death due to bleeding compared to placebo. The authors found no difference in adverse events, including VTE, organ failure, sepsis, and seizure. They also found no difference in the rates of hysterectomy in both groups [23].

Cell salvage has become an important component of operative hemorrhage management for high-risk patients. However, there are important limitations of the cell salvage to consider. Cell salvage can only utilize blood collected into the canister, must have a minimum of 500 ml of blood before the cells can be washed, and returns at most 50% of the washed blood volume back to the patient. Furthermore, this technique does not allow for easy collection of vaginal blood loss, and therefore has limited utility in many obstetric hemorrhage cases. Safe use of the cell-saver has been demonstrated in obstetric patients, particularly when no future pregnancy is planned [24].

#### **3.3. Traditional invasive hemorrhage control techniques**

Definitive management for MAP is to complete a cesarean hysterectomy. A more conservative approach is to leave the placenta and uterus in situ after cesarean delivery of the infant. Follow up plans include observation with or without methotrexate, delayed hysteroscopic resection or interval hysterectomy several weeks later [25, 26]. Although conservative management is successful in 78.4% of cases, this treatment carries an increased risk of postoperative sepsis and hemorrhage, which could necessitate emergent hysterectomy, further increasing the risk of more serious complications [25, 27]. In patients where the placenta is left in place, a risk of bleeding and infection exists for up to 5 months [28]. The risks of this approach may be prohibitively high in patients who cannot accept blood transfusion [25].

Traditional vascular methods of hemorrhage control during cesarean hysterectomy include intraoperative hypogastric artery ligation, uterine artery balloon occlusion with or without embolization, and temporary balloon occlusion of the hypogastric arteries. These methods have come under criticism after studies failed to demonstrate a significant reduction in blood loss or transfusion volumes compared to cesarean hysterectomy without these measures [29–31].

Ligation of the hypogastric arteries theoretically reduces pulse pressure to the uterus; however, it is successful in reducing operative blood loss in fewer than 50% of cases. Furthermore, ligation is estimated to be even less useful in MAP involving the bladder [32]. The literature regarding prophylactic intravascular hypogastric balloon occlusion during cesarean hysterectomy with MAP is mixed. Some studies suggest this technique reduces intraoperative blood loss and transfusion requirements [33], but others have found no difference in blood loss even in combination with uterine artery embolization, concluding that prophylactic intravascular balloon catheters yield no significant benefit [29–31]. These disparate findings are most likely explained by the persistent proximal collateral circulation to the uterus which contributes to venous hemorrhage during surgery [34, 35].

Aortic cross-clamping can aid in hemorrhage control when hypogastric artery occlusion is insufficient [36]. Once surgical hemostasis has been maximized, damage control techniques such as packing and temporary abdominal closure may be useful in cases of disseminated intravascular coagulation.

### **3.4. Management of postoperative anemia**

the anesthesia team can also support this goal. Patient positioning and ventilation mode can alter venous congestion, venous preload, cardiac output and peripheral vascular resistance. Normothermia aids in hemostasis. Additionally, intentional hypotension after delivery of the fetus may help minimize blood loss. A more detailed description of the anesthetic management of patients with MAP is beyond the scope of this article and has been covered elsewhere [16]. Several other methods can improve physiologic tolerance of anemia. Intraoperative volume expansion can be achieved through acute normovolemic hemodilution (ANH). With ANH, venous blood is removed into citrated bags at the start of surgery. The blood remains in a closed circuit with the patient throughout surgery. Crystalloid is administered to increase blood volume until hemorrhage is controlled, at which point ANH blood is transfused [17, 18]. Survival after more than five liters of blood loss has been documented in Jehovah's Witness

There is variability in the products that Jehovah's Witnesses will and will not accept [15]. Generally, whole blood products are prohibited, but some patients will accept fractions, such as hemoglobin, albumin, cryoprecipitate, clotting factors and platelets. A study of Jehovah's Witness patients found that, although most would decline conventional blood products, 76% would accept other blood components [20]. Most will accept crystalloid, colloid, recombinant factor VIIa (rFVIIa), factor VIII (FVIII), fibrinogen, tranexamic acid (TXA), and artificial blood substitutes [14, 15], but use of individual blood components alone may have limitations. Cryoprecipitate, containing FVIII, factor XIII (FXIII), von Willebrand factor (vWF) and fibrinogen, can be used in a postpartum hemorrhage to reduce risk of coagulopathy due to hypofibrinogenemia. However, it is not a substitute for plasma due to the lack of other coagulation factors. There is limited evidence that rFVIIa is helpful in refractory postpartum hemorrhage [21]. Finally, TXA is an antifibrinolytic agent that can be an adjunct for hemorrhage management. A Cochrane review found that TXA decreases blood loss and hemorrhage in both vaginal and cesarean deliveries [22]. The WOMAN trial found that administering TXA for postpartum hemorrhage within 3 hours of delivery decreased the rate of death due to bleeding compared to placebo. The authors found no difference in adverse events, including VTE, organ failure, sepsis, and seizure. They also found

Cell salvage has become an important component of operative hemorrhage management for high-risk patients. However, there are important limitations of the cell salvage to consider. Cell salvage can only utilize blood collected into the canister, must have a minimum of 500 ml of blood before the cells can be washed, and returns at most 50% of the washed blood volume back to the patient. Furthermore, this technique does not allow for easy collection of vaginal blood loss, and therefore has limited utility in many obstetric hemorrhage cases. Safe use of the cell-saver has been demonstrated in obstetric patients, particularly when no future pregnancy is planned [24].

Definitive management for MAP is to complete a cesarean hysterectomy. A more conservative approach is to leave the placenta and uterus in situ after cesarean delivery of the infant. Follow up plans include observation with or without methotrexate, delayed hysteroscopic resection or interval hysterectomy several weeks later [25, 26]. Although conservative management is

patients with placenta percreta using ANH and cell salvage [19].

98 Placenta

no difference in the rates of hysterectomy in both groups [23].

**3.3. Traditional invasive hemorrhage control techniques**

Postoperative management centers around reducing further hemorrhage and providing supportive care for profound anemia. Intensive care monitoring may be required. Hematology consultation may provide guidance regarding hemoglobin optimization with use of high dose erythropoietin, intravenous iron, and other adjuncts [16]. Using pediatric blood collection tubes and avoiding unnecessary lab draws are helpful strategies. In extreme cases, measures to reduce oxygen demand and increase oxygen delivery, including intubation, sedation, and hyperbaric oxygen, may be beneficial [16, 37]. Finally, providers must weigh the risks and benefits of anticoagulation causing increased bleeding against the risk of VTE.
