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

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


using external landmarks for fluoroscopy-free REBOA positioning has not been established. However, alternative methods for positioning in obstetric patients include palpation of the balloon within the aorta during laparotomy or from measurements taken from a pre-operative MRI [42, 43]. Confirming catheter position with an x-ray limits radiation exposure to the fetus compared to the use of fluoroscopy. Any of these positioning methods can be performed in a standard operating room with a standard table. Additionally, the catheter can be inflated, deflated, and repositioned as needed throughout the case without the needing to move the

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

Previous cases of REBOA use in MAP procedures describe placement by an interventional radiologist, however fluoroscopy-free REBOAs in trauma patients are most commonly placed by surgeons or emergency medicine physicians (**Table 3**) [9, 10, 40, 42, 43, 47–50]. These providers are readily available in the hospital, allowing for expedient response times. REBOA insertion, positioning, and inflation can be completed in approximately 2–3 minutes by a

> **Prophylactic or reactive**

**Device used Image guidance**

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None

**Complications**

Medical)

**Length of stay (days)**

patient or obtain additional imaging.

**Author Study** 

Zone 1 occlusion technique

Zone 3 occlusion technique

**Author Occlusion** 

Zone 1 Occlusion Technique

Zone 3 Occlusion Technique

**time (min)**

**design**

**Number of patients**

Bell-Thomas2 CR 1 Reactive 10Fr (BVM

**Blood loss (L)**

Russo1 CR 1 Prophylactic 7Fr (Prytime) None

Luo3 CS 4 Prophylactic 10Fr (Cook) Fluoro Masamoto4 CR 1 Prophylactic 5Fr (Sheft) Fluoro Paull5 CR 1 Prophylactic 8.5Fr (Cook) Fluoro Usman6 CR 1 Reactive NR None Wei7 CS 3 Prophylactic 8Fr (Bard) Fluoro Duan8 CS 4 Prophylactic 8Fr (Bard) Fluoro Wu9 Cohort 88 Prophylactic 5Fr (Cook) Fluoro

> **Blood transfused**

Bell-Thomas2 NR Massive >40 units 4 >60 Vesico-vaginal fistula Luo3 NS 0.8 0.4 L 1.3 NR Ureteral damage ×2

Russo1 32 3 None 4.2 5 None

Masamoto4 80 3.2 1.2 L NR NR None

**Operative time (hours)**

**A**

**B**


**Table 1.** Principles of REBOA.

occlusion to control non-compressible torso hemorrhage was first described in 1954 [38]. The technique was popularized decades later when advances in endovascular technology made catheter-based vascular control more commonplace for repair of aortic aneurysms. Recently, the REBOA catheter has been modified to be percutaneous, wireless, and fluoroscopy-free, leading to its wider adoption for non-compressible hemorrhage control [39].

Despite advancements in technology, the general principles of performing REBOA have remained largely unchanged (**Table 1**). Most published data about REBOA come from trauma literature, but its use in obstetric emergencies and high-risk surgeries is expanding [8–10, 40]. Our institution has successfully documented the use of REBOA in a Jehovah's Witness patient with placenta percreta [41]. This section will discuss the unique considerations for performing REBOA in the high-risk obstetric patient.

#### **4.2. Benefits**

REBOA is an alternative endovascular hemorrhage control technique, which significantly reduces obstetric blood loss compared to combined hypogastric and uterine artery occlusion [8–10]. Reports of prophylactic REBOA use during MAP procedures demonstrate improved maternal outcomes and decreased hysterectomy rates [9]. Compared to uterine or hypogastric artery occlusion techniques, REBOA requires less time for placement and only unilateral arterial puncture making it useful in emergent cases (**Table 2**) [8]. REBOA use has demonstrated lower transfusion volumes than other occlusion techniques [8]. Furthermore, new modifications in REBOA allow placement without fluoroscopy which leads to little to no fetal radiation exposure [8, 42–45].

Catheter measurements based on anatomic landmarks can serve as a basis for positioning of the balloon within the aorta [39, 46]. The effect of a gravid abdomen on the accuracy of


<sup>•</sup> Single arterial access site, concurrent arterial blood pressure monitoring

<sup>•</sup> Little to no fetal radiation exposure

using external landmarks for fluoroscopy-free REBOA positioning has not been established. However, alternative methods for positioning in obstetric patients include palpation of the balloon within the aorta during laparotomy or from measurements taken from a pre-operative MRI [42, 43]. Confirming catheter position with an x-ray limits radiation exposure to the fetus compared to the use of fluoroscopy. Any of these positioning methods can be performed in a standard operating room with a standard table. Additionally, the catheter can be inflated, deflated, and repositioned as needed throughout the case without the needing to move the patient or obtain additional imaging.

Previous cases of REBOA use in MAP procedures describe placement by an interventional radiologist, however fluoroscopy-free REBOAs in trauma patients are most commonly placed by surgeons or emergency medicine physicians (**Table 3**) [9, 10, 40, 42, 43, 47–50]. These providers are readily available in the hospital, allowing for expedient response times. REBOA insertion, positioning, and inflation can be completed in approximately 2–3 minutes by a

occlusion to control non-compressible torso hemorrhage was first described in 1954 [38]. The technique was popularized decades later when advances in endovascular technology made catheter-based vascular control more commonplace for repair of aortic aneurysms. Recently, the REBOA catheter has been modified to be percutaneous, wireless, and fluoroscopy-free,

• Position the balloon in the most distal location appropriate for providing adequate hemorrhage control

• Monitor the patient post-operatively for ischemia–reperfusion injury and arterial access site complications

Despite advancements in technology, the general principles of performing REBOA have remained largely unchanged (**Table 1**). Most published data about REBOA come from trauma literature, but its use in obstetric emergencies and high-risk surgeries is expanding [8–10, 40]. Our institution has successfully documented the use of REBOA in a Jehovah's Witness patient with placenta percreta [41]. This section will discuss the unique considerations for performing

REBOA is an alternative endovascular hemorrhage control technique, which significantly reduces obstetric blood loss compared to combined hypogastric and uterine artery occlusion [8–10]. Reports of prophylactic REBOA use during MAP procedures demonstrate improved maternal outcomes and decreased hysterectomy rates [9]. Compared to uterine or hypogastric artery occlusion techniques, REBOA requires less time for placement and only unilateral arterial puncture making it useful in emergent cases (**Table 2**) [8]. REBOA use has demonstrated lower transfusion volumes than other occlusion techniques [8]. Furthermore, new modifications in REBOA allow placement without fluoroscopy which leads to little to no fetal

Catheter measurements based on anatomic landmarks can serve as a basis for positioning of the balloon within the aorta [39, 46]. The effect of a gravid abdomen on the accuracy of

leading to its wider adoption for non-compressible hemorrhage control [39].

REBOA in the high-risk obstetric patient.

• Gain common femoral arterial access

100 Placenta

**Table 1.** Principles of REBOA.

• Slowly deflate the occlusion balloon when hemodynamics permit • Remove the catheter and sheath promptly, apply pressure to access site

radiation exposure [8, 42–45].

• Little to no fetal radiation exposure

**Table 2.** Benefits of REBOA.

• Can be inserted and adjusted in the operating room

• Can be inserted quickly in response to emergent hemorrhage

• Single arterial access site, concurrent arterial blood pressure monitoring

• Improved hemostasis compared to hypogastric and/or uterine artery occlusion

**4.2. Benefits**




CR: case report; NR: not reported; CS: case series; NS: not specified (grouped in with other causes of hemorrhage).

**Table 3.** Previously reported obstetrical use of REBOA for MAP, 3A. Types of REBOA devices used, 3B. Surgical outcomes of REBOA use for MAP.

trained provider using the ER-REBOA catheter (Prytime Medical, Boerne, TX). In the future, REBOA can be used increasingly for both obstetric emergencies and complicated obstetric scenarios, such as a high-risk obstetric patient with MAP.

#### **4.3. Risks and limitations**

The risks and limitations of REBOA are still being described, and the relative incidence of each is not yet known. The majority of data published on this topic describes the application of REBOA in the trauma population that consists largely of male patients with concomitant hemorrhagic shock. Potential complications from REBOA include those related to arterial access, balloon positioning and inflation, and the physiologic changes that result from inflation and deflation of the device (**Table 4**). From the trauma literature, access site complications are similar to those encountered during other forms of arterial puncture, but may be severe, including limb ischemia requiring amputation [51, 52]. Balloon malposition into an aortic branch vessel or migration into a higher or lower position within the aorta has also been described, sometimes resulting in uncontrolled arterial rupture and death [45, 51]. In animal models, proximal hypertension resulting from aortic occlusion has led to acute heart failure, cerebral edema, and respiratory failure [53, 54]. Distal organ ischemia during occlusion can lead to renal failure, bowel ischemia, and paralysis [51, 52]. Finally, washout of toxic metabolites following balloon deflation can cause rebound hypotension with cardiac collapse [55].

reports of obstetric REBOA use describe occlusion in the infra-renal aorta (Zone 3). However, when Zone 3 occlusion is insufficient, supra-celiac (Zone 1) occlusion may further limit collateral circulation through visceral and lumbosacral vessels and reduce venous back-bleeding. Caution should be used as Zone 1 occlusion is associated with more ischemic complications than Zone 3 occlusion [41]. Extrapolating from trauma literature, Zone 1 occlusion is tolerated for minutes, not hours, and multisystem organ failure and death have been reported after long inflation times [46, 52, 56]. In a prophylactic setting, the lack of pre-existing shock may improve ischemia tolerance and reduce the anticipated risks. However, there may still be a

• Use low-profile (7Fr) sheath • Use ultrasound to obtain CFA access

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

• Consider heparin flushes

• Secure catheter while in place

• Close communication with anesthesia

• Minimize duration of occlusion

• Minimize duration of occlusion

• Slowly, gradually deflate balloon • Communicate with anesthesia

ith balloon deflation

in place

loon control

balloon inflated

• Balloon malposition or migration • Confirm balloon position with x-ray

• Monitor ipsilateral DP/PT pulses while the sheath is

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• Post-procedure angiography prior to sheath removal

• Dedicated provider to maintain REBOA catheter/bal-

• Concurrent administration of vasodilators while

• Reposition from Zone 1 to Zone 3 when able

• Reposition from Zone 1 to Zone 3 when able • Institute partial or intermittent REBOA when able

• Institute partial or intermittent REBOA when able

• Time administration of fluids, calcium, and pressors

Risks of REBOA use can be reduced with multidisciplinary expertise, proper training, and adherence to good techniques. Low-profile, 7Fr common femoral arterial sheaths placed with ultrasound guidance have fewer access site complications than larger 12Fr sheaths. Additionally, distal thrombosis is rare with 7Fr sheaths and limb ischemia requiring amputation has not been reported. REBOA requires a dedicated provider to secure against catheter migration, manage inflation and deflation, and faithfully monitor the ipsilateral lower extremity for ischemia.

significant risk of supra-physiologic aortic pressure leading to heart failure [55].

**4.4. Risk reduction**

• Access site complications, including limb ischemia

• Proximal hypertension that may lead to acute heart

• Distal organ ischemia, that may cause renal failure,

• Washout of toxic metabolites, leading to rebound

**Table 4.** Risks of REBOA and methods of mitigation.

hypotension and cardiac instability

failure, cerebral edema or ARDS

ischemic bowel, or paralysis

requiring amputation

The use of REBOA in obstetrics introduces a different patient population with other comorbidities and requires a different anatomic site of aortic occlusion. The ability to predict complications for this population from the available trauma literature is therefore limited. The potential for severe complications exists and providers performing the procedure should be aware of these risks to improve patient management and the informed consent process.

The optimal location and duration of aortic occlusion is controversial. The primary blood supply to the gravid uterus includes the uterine arteries and collaterals from other branches of the internal iliac artery. However, particularly in cases of abnormal placentation, robust collaterals from the external iliac, ovarian, and other systemic arteries exist [34, 35]. Most


**Table 4.** Risks of REBOA and methods of mitigation.

reports of obstetric REBOA use describe occlusion in the infra-renal aorta (Zone 3). However, when Zone 3 occlusion is insufficient, supra-celiac (Zone 1) occlusion may further limit collateral circulation through visceral and lumbosacral vessels and reduce venous back-bleeding. Caution should be used as Zone 1 occlusion is associated with more ischemic complications than Zone 3 occlusion [41]. Extrapolating from trauma literature, Zone 1 occlusion is tolerated for minutes, not hours, and multisystem organ failure and death have been reported after long inflation times [46, 52, 56]. In a prophylactic setting, the lack of pre-existing shock may improve ischemia tolerance and reduce the anticipated risks. However, there may still be a significant risk of supra-physiologic aortic pressure leading to heart failure [55].

#### **4.4. Risk reduction**

trained provider using the ER-REBOA catheter (Prytime Medical, Boerne, TX). In the future, REBOA can be used increasingly for both obstetric emergencies and complicated obstetric

**Table 3.** Previously reported obstetrical use of REBOA for MAP, 3A. Types of REBOA devices used, 3B. Surgical

CR: case report; NR: not reported; CS: case series; NS: not specified (grouped in with other causes of hemorrhage).

The risks and limitations of REBOA are still being described, and the relative incidence of each is not yet known. The majority of data published on this topic describes the application of REBOA in the trauma population that consists largely of male patients with concomitant hemorrhagic shock. Potential complications from REBOA include those related to arterial access, balloon positioning and inflation, and the physiologic changes that result from inflation and deflation of the device (**Table 4**). From the trauma literature, access site complications are similar to those encountered during other forms of arterial puncture, but may be severe, including limb ischemia requiring amputation [51, 52]. Balloon malposition into an aortic branch vessel or migration into a higher or lower position within the aorta has also been described, sometimes resulting in uncontrolled arterial rupture and death [45, 51]. In animal models, proximal hypertension resulting from aortic occlusion has led to acute heart failure, cerebral edema, and respiratory failure [53, 54]. Distal organ ischemia during occlusion can lead to renal failure, bowel ischemia, and paralysis [51, 52]. Finally, washout of toxic metabolites following balloon deflation can cause rebound hypotension with cardiac collapse [55]. The use of REBOA in obstetrics introduces a different patient population with other comorbidities and requires a different anatomic site of aortic occlusion. The ability to predict complications for this population from the available trauma literature is therefore limited. The potential for severe complications exists and providers performing the procedure should be aware of these risks to improve patient management and the informed consent process.

The optimal location and duration of aortic occlusion is controversial. The primary blood supply to the gravid uterus includes the uterine arteries and collaterals from other branches of the internal iliac artery. However, particularly in cases of abnormal placentation, robust collaterals from the external iliac, ovarian, and other systemic arteries exist [34, 35]. Most

scenarios, such as a high-risk obstetric patient with MAP.

**4.3. Risks and limitations**

outcomes of REBOA use for MAP.

**Author Occlusion** 

**time (min)**

**Blood loss (L)**

**Blood transfused**

Paull5 NR 1.4 None NR 7 None Usman6 NR Massive 40 units 6.5 9 NR Wei7 NS 3.33 (2–6) 3.7 (2–7) NS NS NS Duan8 22.4 0.6 0.4 L 1.1 5.5 None Wu9 23.6 0.9 0.4 L 1.1 5.1 None

**Operative time (hours)** **Length of stay (days)**

**Complications**

**B**

102 Placenta

Risks of REBOA use can be reduced with multidisciplinary expertise, proper training, and adherence to good techniques. Low-profile, 7Fr common femoral arterial sheaths placed with ultrasound guidance have fewer access site complications than larger 12Fr sheaths. Additionally, distal thrombosis is rare with 7Fr sheaths and limb ischemia requiring amputation has not been reported. REBOA requires a dedicated provider to secure against catheter migration, manage inflation and deflation, and faithfully monitor the ipsilateral lower extremity for ischemia.

During balloon inflation, the anesthesia team should work to off-set unwanted blood pressure augmentation and maintain normal physiologic pressures. The surgical teams should aim to achieve hemorrhage control rapidly to keep the duration of Zone 1 occlusion to a minimum. Other methods used to reduce ischemia include intermittent or partial balloon deflation and relocating the REBOA balloon to Zone 3 when able [55]. These techniques will allow some distal blood flow to perfuse ischemic tissues and prolong the overall duration of REBOA use. Providers should be aware that balloon deflation is associated with the rapid redistribution of circulating blood volume and the washout of ischemic metabolites, including a bolus of potassium, which can result in rebound hypotension and cardiac instability [55]. The combination of partial occlusion and relocation from Zone 1 to Zone 3, along with close communication with the anesthesia providers to time fluid and drug administration with inflation and deflation, can aid in maintaining hemodynamic stability throughout surgery.

examine the risks and benefits of REBOA compared to other methods of hemorrhage control utilized in the West. Although case reports and case series have shown that REBOA can successfully provide temporary control of obstetric hemorrhage, up to three liters of blood loss has been reported in these cases despite aortic occlusion. Larger studies are needed to quantify the expected hemorrhage volume during aortic occlusion to help inform perioperative plans. Furthermore, instructions on REBOA use and placement for the obstetric patient are extrapolated from the trauma literature. Whether external landmarks on the gravid abdomen can be used reliably for positioning of REBOA has yet to be determined. More research is needed to establish whether imaging is needed to verify balloon position prior to inflation, and to assess the associated risk of radiation exposure to the fetus. The optimal zone of REBOA inflation is not known for obstetric hemorrhage. More research should focus on defining collateral pathways for circulation to the gravid uterus, especially in the case of abnormal placentation. Additionally, the effect of proximal vs. distal occlusion on blood pressure support during various stages of hemorrhagic shock should be established to aid in defining the optimal level

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of occlusion for initial balloon inflation in prophylactic and reactive settings.

help delineate more definitive guidelines for this population.

**6. Recommendations**

Finally, the risks of REBOA are also generated from its reactive placement in trauma patients experiencing hemorrhagic shock. Although it can be assumed that prophylactic use of REBOA during planned obstetric procedures will have decreased risk compared to trauma situations, more research is needed to investigate this use of REBOA. As the adoption of REBOA for obstetric hemorrhage becomes more prevalent, it is expected that increasing evidence will

For high-risk patients with MAP, thorough planning throughout the prenatal period is critical to successful management. Prenatal optimization of hemoglobin and preoperative involvement of a multidisciplinary team can improve maternal outcomes. If blood products are not readily available or are declined by the patient, alternative options should be discussed. Clearly eliciting if blood fractions, clotting factors, and TXA will be accepted by the patient can assist in surgical planning. Meticulous surgical techniques and clear communication with the anesthesia team can minimize intraoperative hemorrhage. Additional adjuncts such as ANH and cell salvage may ease the effects of blood loss. Consideration of REBOA use may decrease the volume of blood lost and the need for transfusion. Planning for REBOA use in a proactive and prophylactic

Implementing REBOA in the obstetric patient requires careful multidisciplinary management and clear communication throughout the perioperative period. General principles of vascular access should be respected. Minimizing the risk of limb ischemia requires selecting the smallest sheath possible to accommodate the selected balloon catheter, frequent vascular checks of both lower extremities, consideration of post-procedural angiography, and prompt sheath removal. The duration of balloon inflation should be minimized, and intermittent or partial balloon deflation should be used as adjuncts to reduce ischemia when necessary. Anticipating

setting may limit the risks of the procedure and improve morbidity and mortality.

There is a dearth of published information about management of intra-arterial balloons during high-risk obstetric procedures. Of all reported cases, there has been only one documented aortic rupture due to a smaller than expected aortic diameter [45]. Few cases describe flushing the sheath or catheters, although doing so is a well-established principle of vascular surgery. Whether the flush solution should contain heparin is additionally controversial when these catheters are used for hemorrhage control in patients that cannot receive blood. The authors' practice is to use 30 ml 2% heparin (2 units of heparin per 100 ml of crystalloid) through the sheath and another 30 ml through the central lumen of the REBOA catheter every 10 minutes, while monitoring thromboelastography to ensure the absence of systemic coagulopathy. Frequent monitoring of distal pulses in the ipsilateral extremity should be maintained throughout the case and for 24 hours after sheath removal. Continuous Doppler may be a helpful adjunct to aid in early detection of arterial access complications.

The risks and benefits of anticoagulation deserve special consideration in this patient population. Pregnancy itself confers a hypercoagulable state. These patients may be at even higher risk of clot formation due to the administration of TXA, erythropoietin, cryoprecipitate or other coagulation factors. Postoperatively, VTE risk remains high in the setting of immobility and/or symptomatic anemia. In the immediate postoperative period, the risk of death from hemorrhage may outweigh the risks from VTE. Within several days of surgery however, the probability of hemorrhage decreases, justifying prophylactic heparin administration to reduce the risk of VTE.
