The Journal of Emergency Medicine, Vol. 52, No. 5, pp. 715–722, 2017� 2017 Elsevier Inc. All rights reserved.

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http://dx.doi.org/10.1016/j.jemermed.2017.01.014

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Techniquesand Procedures

ULTRASOUND-GUIDED RESUSCITATIVE ENDOVASCULAR BALLOON OCCLUSIONOF THE AORTA IN THE RESUSCITATION AREA

Takayuki Ogura, MD,*† Alan Kawarai Lefor, MD, MPH, PHD,‡ Mitsunobu Nakamura, MD, PHD,* Kenji Fujizuka, MD,*

Kousuke Shiroto, MD,* and Minoru Nakano, MD, PHD*

*AdvancedMedical EmergencyDepartment andCritical CareCenter, JapanRedCrossMaebashi Hospital, Maebashi, Japan, †Department ofEmergency Medicine, Jichi Medical University, Tochigi, Japan, and ‡Department of Surgery, Jichi Medical University, Tochigi, Japan

Reprint Address: Takayuki Ogura, MD, Advanced Medical Emergency Department and Critical Care Center, Japan Red Cross MaebashiHospital, 371-0014 Asahi-cho 3-21-36, Maebashi, Gunma, Japan

, Abstract—Background: In trauma resuscitation withresuscitative endovascular balloon occlusion of the aorta(REBOA), urgent and accurate placement of the catheterin the resuscitation area without fluoroscopy can shortenthe time from admission to REBOA, allowing rapid, tempo-rary control of bleeding. Discussion: The experience-basedprotocol in our center for ultrasound-guided REBOA inthe resuscitation area without fluoroscopy is as follows: thefemoral artery is punctured and a guidewire inserted; so-nography is used to verify that the guidewire is in theabdominal aorta; the position of the balloon is confirmedwith ultrasound after estimating the distance to the clavicle,and the pressure in the radial artery and sheath is used tomonitor correct positioning; connect the pressure trans-ducer to the catheter sheath for continuous monitoring ofthe blood pressure in the sheath, and inflate the balloon untilthe blood pressure tracing at the sheath has disappeared;check the pulse in the left radial artery, and withdraw thecatheter slightly if the pulse in the radial artery is notpalpable or is decreased (if this pulse is not palpable ordecreased, the balloon is in the aortic arch). In this retro-spective review of our REBOA protocol, between April2012 and March 2016, 34 patients were enrolled. Two pa-tients had complications, including dissection of the femoralartery in one and difficult percutaneous vascular access inanother. Median time needed to complete the procedurewas 8 min. Overall, 24 of 34 patients survived more than24 h (72%), and overall mortality was 47%. Patients wholived more than 24 h, and then died had severe traumatic

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brain injury or septic shock. Conclusions: Ultrasound-guided REBOA is presented. Monitoring the blood pressurein the left radial artery allows us to determine adequate posi-tioning of the balloon, and the blood pressure in the cathetersheath located in the femoral artery should also be moni-tored to prevent aortic injuries caused by the overinflationof the balloon. � 2017 Elsevier Inc. All rights reserved.

, Keywords—trauma; hemorrhage; resuscitative endo-vascular balloon occlusion of the aorta

INTRODUCTION

Resuscitative endovascular balloon occlusion of the aorta(REBOA) can temporarily control massive subdiaphrag-matic hemorrhage. In recent years, REBOA has beenused in the management of patients with hemorrhagefrom a number of sources (1–3). There are reports usingREBOA in the management of patients with rupturedabdominal aortic aneurysms, abdominal and pelvictrauma, gastrointestinal hemorrhage, postoperativehemoperitoneum, and postpartum hemorrhage (4–8).

As yet, there is no single best procedure to achieve fastand adequate positioning of the balloon catheter. In RE-BOA, accurate positioning is important to maximize thepotential for hemorrhage control and improved survival,and limit the development of REBOA-associated compli-cations. To achieve these goals, REBOA is generally

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performed under fluoroscopy guidance (9). However, thisoften necessitates moving the patient from the resuscita-tion area to the radiology department. This transfer pro-longs the interval from arrival to the completion ofREBOA, and can lead to a variety of other problems.‘‘Time is gold’’ for critically ill patients with massivehemorrhage, and a simple procedure to perform rapidand accurate REBOA in the resuscitation area is needed(10). The aim of this report is to present our protocolfor REBOA in the resuscitation area without fluoroscopy.The catheter is inserted under ultrasound guidance. Cor-rect balloon positioning is ascertained by blood pressuremonitoring in the left radial artery, and adequate occlu-sion ascertained by monitoring the blood pressuremeasured from the catheter sheath.

DISCUSSION

Procedure

Device.The Block Balloon� (Senko Medical InstrumentMfg. Co., Ltd, Tokyo, Japan) is an intra-aortic balloon oc-clusion catheter, used in our center (Figure 1A). The cath-eter is 9Fr and is inserted through a 10Fr sheath. Becausethe balloon is folded and rolled before inflation, thesheath is larger than the catheter, which facilitates cath-eter insertion. A hard wire stylet accompanies the BlockBalloon, which is inserted through the central lumen ofthe catheter (Figure 1B). When the balloon is inflated,the balloon moves along with blood flow, resulting in ashifted position. The insertion of the hard wire styletthrough the central lumen of the catheter prevents thisshifting of the balloon position caused by blood flow.

Catheter Insertion Technique

The aortic balloon occlusion catheter is inserted throughthe femoral artery using the Seldinger technique using thefollowing protocol, which incorporates ultrasound guid-ance rather than fluoroscopy (Figure 2):

Figure 1. Intra-aortic balloon occlusion catheter. (A) Block Balloon

1. The femoral artery is punctured and a guidewireinserted.

2. Sonography is used to verify that the guidewire isin the abdominal aorta (Figure 3).

3. The sheath is inserted over the guidewire.4. The length of catheter needed is roughly esti-

mated by measuring the distance from the femoralartery puncture site to the left clavicle.

5. The aortic balloon occlusion catheter is insertedover the guidewire to the estimated length.

6. Verify catheter position in the abdominal aortaand assure that the catheter tip is above the dia-phragm by ultrasound imaging (Figure 4) (thetarget position of the balloon is zone 1 of the de-scending aorta; Figure 5) (11).

7. Connect the pressure transducer to the side port ofthe sheath for continuous monitoring of the bloodpressure in the sheath, positioned in the femoralartery.

8. Insert the hard wire stylet into the central lumen ofthe catheter and inflate the balloon by injectingnormal saline gradually until the blood pressuretracing at the side port of the sheath has disap-peared (Figure 6).

9. Check the pulse in the left radial artery and with-draw the catheter slightly if the pulse in the radialartery is not palpable or is decreased (Figure 6) (ifthe pulse in the left radial artery is not palpable ordecreased, the balloon is in the aortic arch).

10. Verify the position of the balloon in the descend-ing aorta (zone 1) using transesophageal echocar-diography, if needed (Figure 7) (consultation withan intensivist or anesthesiologist may be neces-sary, but the balloon in zone 1 is easily seen usingtransesophageal echocardiography).

11. If the catheter needs to be moved after initial posi-tioning, deflate the balloon, reposition, inflate theballoon again, and check the pressure in the leftradial artery.

�. (B) The rigid stylet is placed through the central lumen.

Figure 2. Step-by-step procedure for resuscitative endovascular balloon occlusion of the aorta.

Ultrasound-Guided REBOA in the Resuscitation Area 717

In the resuscitation of patients suffering massivepost-traumatic hemorrhage when REBOA is indicated,urgent and accurate placement of the balloon catheteris necessary to maximize the chance of survival. How-ever, REBOA is generally performed under fluoro-scopic guidance necessitating transfer from theresuscitation area to the radiology department (9).Placement of the balloon catheter in the resuscitationarea without fluoroscopy may shorten the time from

Figure 3. An axial view of the abdominal aorta using ultrasound imaIVC = inferior vena cava.

admission to REBOA, allowing rapid, temporary con-trol of bleeding from sub-diaphragmatic injuries. Inrecent years, the ability to accurately introduce, posi-tion, and inflate REBOA devices without fluoroscopyhas represented a paradigm shift, allowing thisprocedure to be performed in urgent settings (10).The rapid, temporary control of bleeding withREBOA in the resuscitation area may lead toimproved outcomes.

ging. The guidewire is shown in the abdominal aorta (arrow).

Figure 4. A sagittal view of the abdominal aorta with ultrasound imaging. The catheter passeswithin the abdominal aorta (arrow)and the balloon is located above the diaphragm.

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Technical Skills in Abdominal Ultrasound Imaging

Position the probe at the mid-upper abdomen and scanaxial images of zone 2 of the abdominal aorta, which isusually located in front of the lumbar vertebra. Pressthe probe toward to the abdominal wall if a clear imageis not scanned because of gas in the stomach or transversecolon. When the probe is pressed, the gas under the probebecomes free and a clear image can be scanned. If thewire is in zone 2 of the abdominal aorta, the wire isalso scanned with artifact (Figure 3). After scanning theaxial image of abdominal aorta, turn the probe 90 degreesin a clockwise direction, and a sagittal image is scanned.In this sagittal image, the wire is estimated to have beeninserted in the descending aorta through zones 2 and 3of the abdominal aorta, is identified (Figure 4).

Experience

In our center, REBOA has been performed in 34 patientswith severe abdominal or pelvic trauma between April2012 and March 2016. Their background is summarizedin Table 1. Median agewas 67.5 years and all patients suf-fered blunt trauma. Median interval to complete REBOA

was 8min.Median Injury Severity Scorewas high andme-dian probability of survival calculated by the Trauma andInjury Severity Score methods was low (31%). The 24-hmortality was 29% and overall mortality was 47%, but75% (3 of 4) of patients alivemore than 24 h but ultimatelydied had suffered severe traumatic brain injury, and 25% (1of 4) died due to septic shock related to an open pelvic frac-ture and pelvic osteomyelitis. Two patients (6%) devel-oped complications related to REBOA. One had afemoral artery dissection and in the other, percutaneous ac-cess to the artery could not be gained (a cut-down proced-ure was performed and REBOAwas completed).

According to a recent review, the overall mortality oftrauma patients undergoing REBOA was 75.0% (416 of555) (this mortality was analyzed using only availabledata) (12). However, the overall mortality in our center is47% (16 of 18), which is significantly less (p < 0.001).These data suggest that ultrasound-guided REBOA in theresuscitation area can reduce overall mortality.

Avoid Complications

REBOA has been associated with complications,including malposition, vascular injuries, organ ischemia,

Figure 5. Zones of the aorta.

Ultrasound-Guided REBOA in the Resuscitation Area 719

and others. To avoid these complications, a reliable andsafe REBOA technique is necessary.

Position the balloon above zone 2 guided by ultrasound.For adequate positioning of the balloon in the descendingaorta (zone 1), identification of the guidewire or ballooncatheter in the abdominal aorta is important. In thisultrasound-guided REBOA procedure, providers shouldidentify it in the abdominal aorta (zone 2) by axial andsagittal ultrasonography scan. If it cannot be identified,the guidewire may be malpositioned. If they can, theballoon will be positioned above zone 2 through theguidewire in the abdominal aorta. The balloon cathetercan be positioned above zone 2 using abdominal ultra-sound imaging alone.

Avoid occlusion of aortic arch.For positioning the occlu-sion balloon in zone 1 (not in the aortic arch), the locationof the tip of the catheter is important because occlusion ofthe aortic arch causes ischemia of the upper limbs orbrain. Verification of the position of the balloon abovethe diaphragm is made by ultrasound imaging. However,the tip of the balloon catheter in zone 1 may not be visu-alized with abdominal ultrasound imaging. Using abdom-

inal ultrasound guidance alone, occlusion of the aorticarch can occur. To avoid this complication, monitoringthe blood pressure in the left radial artery is a part ofthe protocol for REBOA. When the balloon is success-fully located in zone 1 with occlusion of the aorta, thepulse in the left radial artery is easily palpable and theblood pressure may be increased after inflation of theballoon. If the pulse in the left radial artery is not palpableor the blood pressure is decreased at the time of theballoon inflation, the balloon may be in the aortic archwith no blood flow to the arch branches. Thus, the posi-tion of the occluding balloon can be detected and success-ful positioning of the balloon in the zone 1 is assured bymonitoring the blood pressure in the left radial artery.

The loss of a pulse oximetry trace in the lower extrem-ity or the loss of a left brachial pulse is easy, common, andwidely used, according to the review report (12). Use ofthe left radial artery monitoring for gauging malpositionof the balloon, which is presented in this report has asmall novelty. The left carotid artery or brachial arteryis a second choice for monitoring, if the left radial arteryis not available (e.g., amputated limbs). There is noanswer about which monitoring is the best way for thispurpose.

Figure 6. The waveform of the blood pressure upon balloon inflation. The waveform in the left radial artery is clearly seen. Thewaveform in the catheter sheath in the femoral artery is flattened.

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Avoid overinflation.Overinflation of the balloon can leadto an iatrogenic aortic injury, and may occur if the oper-ator continues to inflate the balloon without noticingcomplete occlusion of the aorta. For safe and adequateballoon inflation, an objective indicator reflecting occlu-sion of the aorta is necessary. However, as yet, there is nosingle established indicator. Aortic occlusion by theballoon catheter is usually identified by the loss offemoral artery pulsation, elevation of the blood pressurein the radial artery, increased resistance in inflating theballoon, or the fluoroscopic guidance using a two-dimensional image. Despite careful conduct of the pro-cedure, because of the absence of such an indicator, aorticrupture caused by overinflation of the balloon can occur.

Blood pressure measured at the side port of the cath-eter sheath (sheath pressure) may be an indicator of aorticocclusion. In the REBOA procedure presented here, thesheath pressure was continuously monitored during infla-tion and deflation of the balloon. As the balloon is inflatedgradually, the blood flow in the iliac artery decreases andthe sheath pressure also decreases. When the balloon isfully inflated and the aorta is completely occluded, thesheath pressure reaches a nadir and the waveform isalmost flat (Figure 5). Thus, blood flow distal to the

occluding balloon is monitored by measuring the bloodpressure at the side port of the catheter sheath, and com-plete occlusion of the aorta is recognized with flatteningof the waveform, which can be determined without addi-tional invasive procedures or devices.

Consideration of other techniques to avoid complica-tions. In this historical review of REBOA, 1 patientwith difficult percutaneous vascular access was encoun-tered. Real-time ultrasound-guided puncture of thefemoral artery can help overcome this difficulty. This pro-cedure is commonly used to insert a central venous cath-eter in the intensive care unit and we consider that thistechnique can be applied to access to femoral artery.

REBOA provider.The ultrasound-guided REBOA proced-ure described here is usually performed by well-trainedemergency physicians in the resuscitation area. Previ-ously reported cases of REBOA, guided by fluoroscopicimaging, were performed by trauma surgeons, and inter-ventional or vascular specialists (9). Abdominal ultra-sound is commonly used for screening for abdominaldisease such as abdominal aortic aneurysms (13,14).Some training is needed, but ultrasound imaging of the

Figure 7. A sagittal view of the descending aorta is shownwith transesophageal echocardiography. The balloon is inflated in thedescending aorta and the aorta is occluded. The transesophageal echo (TEE) probe is positioned in the middle esophagus. Thisimage was scanned using the following procedure: Position the probe in the mid-esophagus and turn the echo shaft counter-clockwise. The short axis viewof the descending aorta and the balloon in the aorta is identified. Finally, the long-axis viewof aortaand the balloon is scanned by rotation of the transducer angle from 0 to 90 degrees.

Ultrasound-Guided REBOA in the Resuscitation Area 721

abdominal aorta by an emergency physician can be usedto visualize the abdominal aorta and determine thepresence of abdominal aortic aneurysms (15). In recent

Table 1. Summary of Trauma Patients UndergoingResuscitative Endovascular Balloon Occlusion ofthe Aorta

Characteristic REBOA (n = 34)

Age, y, median, IQR 67.5 (53–82)Sex, male, n (%) 22 (64.7)Mechanism, blunt, n (%) 34 (100)Injury Severity Score, median (IQR) 50 (36–59)Revised Trauma Score, median (IQR) 6.233 (5.146–7.108)Provability of survival, %, median (IQR) 31.4 (9.9–65.1)Interval to complete REBOA, min,

median (IQR)8 (5–10)

Complications, n (%) 2 (5.9)Femoral artery dissection 1Difficult percutaneous vascular access 1

Overall mortality, n (%) 16 (47.1)24-h mortality, n (%) 10 (29.4)

IQR = interquartile range; REBOA = resuscitative endovascularballoon occlusion of the aorta.

paper by Guliani and colleagues, it was shown that a sur-geon can reliably identify a central aortic guidewire inboth transverse and sagittal orientations during thefocused abdominal sonography for trauma procedure(16). Focused abdominal sonography for trauma andemergency ultrasound imaging of the abdominal aortaare also routine and necessary skills for emergency phy-sicians. These physicians can readily expand their ultra-sound capabilities to include ultrasound-guided REBOAwithout fluoroscopy.

In this protocol for REBOA, verification of the balloonposition in the descending aorta using transesophagealechocardiography is recommended, if needed and avail-able. Commonly, transesophageal echocardiography isnot available in emergency department or resuscitationarea. Consultation with an intensivist or anesthesiologistis needed. However, in our center, when a trauma code isactivated, the trauma team including an intensivist andtrauma physician comes to the resuscitation area. Ourtrauma code brings easy access to transesophageal echo-cardiography, which might be limited in other emergency

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departments without access to intensivists or anesthesiol-ogists for trauma management in the resuscitation area.

Study Limitations

The REBOA protocol presented is just an experience-based procedure in a single center. Additional study ofthis procedure is necessary and must be focused on safety,its effect on the post-injury interval to complete REBOA,and the patient outcomes. Despite several protocols forREBOA use, there is a paucity of prospective, compara-tive data to inform physicians as to the optimal approach.High-quality, prospective clinical trials are needed toaddress this gap in the resuscitation literature.

CONCLUSIONS

Ultrasound-guidedREBOA is presented,which enabled usto perform REBOA in the resuscitation area without pa-tient transport to the radiology department for fluoroscopy.Monitoring the blood pressure in the left radial artery al-lows us to determine adequate positioning of the balloon,and the blood pressure in the catheter sheath located inthe femoral artery should also be monitored to preventaortic injuries caused by overinflation of the balloon.

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