Open versus endovascular REBOA control of blood loss during cesarean delivery in the placenta accreta spectrum: A single-center retrospective case control study.

OBJECTIVE: The aim of this study was to compare two vascular control options for blood loss prevention and hysterectomy during cesarean delivery (CD2): endovascular balloon occlusion of the aorta (REBOA3) and open bilateral common iliac artery occlusion (CIAO4) in women with extensive placenta accreta spectrum (PAS5). STUDY DESIGN: This was retrospective comparison of cases of PAS using either CIAO (October 2017 through October 2018) or REBOA (November 2018 through November 2019) to prevent pathologic hemorrhage during scheduled CD. Women with confirmed placenta increta/percreta underwent either CD then intraoperative post-delivery, pre-hysterectomy open vascular control of both CIA6 (CIAO group) or pre-operative, ultrasound-guided, fluoroscopy-free REBOA followed by standard CD and balloon inflation after fetal delivery (REBOA group). Intraoperative blood loss, transfusion volumes, surgical time, blood pressure, maternal and neonatal outcomes, hospitalization length and postoperative complications were compared. RESULTS: The REBOA and CIAO groups included 12 and 16 women, respectively, with similar median age of 35 years and gestational age of 34-35 weeks. All REBOA catheters were successfully placed into aortic zone three under ultrasound guidance. The quantitated median intraoperative blood loss was significantly lower for the REBOA group, (541 [IQR 300-750] mL) compared to the CIAO group (3331 [IQR 1150-4750] mL (P = 0.001). As a result, the total volume of fluid and blood replacement therapy was significantly lower in the REBOA group (P < 0.05). Median surgical time in the REBOA group was less than half as long: 76 [IQR 64-89] minutes compared to 168 [IQR 90-222] minutes in the CIAO group (P = 0.001). None of the women with REBOA required hysterectomy, while 8/16 women in the CIAO group did (P = 0.008). Furthermore, the post-anesthesia recovery and hospital discharge times in the REBOA-group were shorter (P < 0.05). One thromboembolic complication occurred in each group. The only REBOA-associated complication was non-occlusive femoral artery thrombosis, with no surgical management required. No maternal or neonatal deaths occurred in either group. CONCLUSION: Fluoroscopy-free REBOA for women with PAS is associated with improved vascular control, perioperative blood loss, the need for transfusion and hysterectomy and reduces surgical time when compared to bilateral CIAO.

Ultrasound-guided versus blind vascular access followed by REBOA on board of a medical helicopter in a hemorrhagic ovine model.

BACKGROUND: The aim of this study is to evaluate the feasibility of en-route resuscitative endovascular balloon occlusion of the aorta (REBOA) on board of a helicopter. METHODS: Six sedated male sheep (weighing 42-54 kg) underwent a controlled hemorrhage until the systolic blood pressure (BP) dropped to <90 mmHg, and were placed into a low capacity Eurocopter AS-350 (France). During the 30-minutes normal flight, every animal underwent blind (left side) and ultrasound-guided (US) (right side) vascular access (VA) to the femoral artery followed by REBOA: the first catheter (Rescue balloon, Japan) - into Zone I, the second one (MIT, Russia) - Zone III. In case of blind VA failure, an alternate US-puncture was attempted. Six experienced flight anesthetists were enrolled into the study. Vascular access and REBOA catheter placement (confirmed by X-Ray later) success rate and timing were recorded. RESULTS: Among six blind punctures one was successful, 2/6 - were into the vein, 3/6 - completely failed and switched to US-punctures (making total number of US-punctures nine). Eight out of nine US-punctures were successful. However, correct wire insertion and sheath placement was performed in 1/6 animal in the 'blind' group and only in 6/9 animals in the 'US' group. It took a median of 65 seconds (range 5-260) for US-puncture and a median of 4 minutes to get the sheath in. Among the 9 VAs, there were 2 REBOA failures (1 ruptured balloon [MIT] and 1 mistaken vena cava placement primarily recognized by a sudden drop of BP and later confirmed by X-Ray). Five out of seven balloons were placed in a desired intra-aortic position: 4/5 in Zone I and 1/2 - in Zone III. A median time for a successful REBOA procedure was 5.0 (range 2.5-10.0) minutes (1 min after sheath placement). CONCLUSION: Our study demonstrates the potential feasibility of the en-route REBOA which can be performed within 5 minutes. Ultrasound-guidance is critically important to achieve en-route VA.

Battlefield Extracorporeal Cardiopulmonary Resuscitation for Out-of-Hospital Cardiac Arrest: A Feasibility Study During Military Exercises.

PURPOSE: To evaluate the feasibility of prehospital extracorporeal cardiopulmonary resuscitation (E-CPR) in the military exercise setting. METHODS: Three 40kg Sus scrofa (wild swine) underwent controlled 35% blood loss and administration of potassium chloride to achieve cardiac arrest (CA). During CPR, initiated 1 minute after CA, the animals were transported to Role 1. Femoral vessels were cannulated, followed by E-CPR using a portable perfusion device. Crystalloid and blood transfusions were initiated, followed by tactical evacuation to Role 2 and 4-hour observation. RESULTS: All animals developed sustained asystole. Chest compressions supported effective but gradually deteriorating blood circulation. Two animals underwent successful E-CPR, with restoration of perfusion pressure to 80mmHg (70-90mmHg) 25 and 23 minutes after the induction of CA. After transportation to Role 2, one animal developed abdominal compartment syndrome as a result of extensive (9L) fluid replacement. The other animal received a lower volume of crystalloids (4L), and no complications occurred. In the third animal, multiple attempts to cannulate arteries were unsuccessful because of spasm and hypotension. Open aortic cannulation enabled the circuit to commence. No return of spontaneous circulation was ultimately achieved in either of the remaining animals. CONCLUSION: Our study demonstrates both the potential feasibility of battlefield E-CPR and the evolving capability in the care of severey injured combat casualties.

Defining degree of aortic occlusion for partial-REBOA: A computed tomography study on large animals.

INTRODUCTION: Partial resuscitative endovascular balloon occlusion of the aorta (P-REBOA) is a modified REBOA technique designed to help ameliorate ischemia-reperfusion injury. The balloon is partially deflated, allowing a proportion of aortic flow distal to the balloon. The aim of this study is to use an ovine model of haemorrhagic shock to correlate the degree of occlusion to several hemodynamic indices. MATERIALS AND METHODS: Six sheep weighing 35-46 kg underwent a controlled venous haemorrhage inside a CT scanner until the systolic arterial pressure (AP) dropped to <90 mmHg. A balloon positioned in an aortic zone I was incrementally filled with 1 mL of saline, with serial measurement of the proximal (carotid artery) and distal (femoral artery) mean APs (MAP) and intra-balloon pressure (IBP), along with CT imaging, following each inflation, until full occlusion was achieved. RESULTS: A diameter of the aorta at zone I was 16.0 (15.7-17.2) mm, with a cross-sectional area of 212 (194-233) mm2. Median volume of saline injected into the balloon until total occlusion was 7.0 (6.3-8.5) mL. During gradual balloon inflation, proximal MAP increased and distal MAP decreased proportionate to the degree of occlusion, in a linear fashion (proximal: r2 = 0.85, p < 0.001; distal: r2 = 0.95, p < 0.001). The femoral/carotid (F/C) pressure gradient also demonstrated a linear trend (r2 = 0.90, p < 0.001). The relationship between percentage occlusion and IBP was sigmoid. MAP values became significantly different at 40-49% occlusion and more (p < 0.01). Furthermore, a drop in the distal pulse pressure from 7.0 (5.5-16.5) to 2.0 (1.5-5.0) mmHg was observed at 80% occlusion. All animals had femoral pulse pressure <5 mmHg at 80% of occlusion and more, which also coincided with the observed loss of pulsatility of the femoral wave-form. CONCLUSION: Serial CT angiography at an ovine model of haemorrhagic shock demonstrates a correlation between the femoral MAP, F/C pressure gradient and degree of zone I P-REBOA during the staged partial aortic occlusion. These parameters should be considered potential parameters to define the degree of P-REBOA during animal research and clinical practice.

The pitfalls of resuscitative endovascular balloon occlusion of the aorta: Risk factors and mitigation strategies.

Despite technological advancements, REBOA is associated with significant risks due to complications of vascular access and ischemia-reperfusion. The inherent morbidity and mortality of REBOA is often compounded by coexisting injury and hemorrhagic shock. Additionally, the potential for REBOA-related injuries is exaggerated due to the growing number of interventions being performed by providers who have limited experience in endovascular techniques, inadequate resources, minimal training in the technique, and who are performing this maneuver in emergency situations. In an effort to ultimately improve outcomes with REBOA, we sought to compile a list of complications that may be encountered during REBOA usage. To address the current knowledge gap, we assembled a list of anecdotal complications from high-volume REBOA users internationally. More importantly, through a consensus model, we identify contributory factors that may lead to complications and deliberate on how to recognize, mitigate, and manage such events. An understanding of the pitfalls of REBOA and strategies to mitigate their occurrence is of vital importance to optimize patient outcomes.

Field and en route resuscitative endovascular occlusion of the aorta: A feasible military reality?

BACKGROUND: Severe noncompressible torso hemorrhage remains a leading cause of potentially preventable death in modern military conflicts. Resuscitative endovascular occlusion of the aorta (REBOA) has demonstrated potential as an effective adjunct to the treatment of noncompressible torso hemorrhage in the civilian early hospital and even prehospital settings-but the application of this technology for military prehospital use has not been well described. We aimed to assess the feasibility of both field and en route prehospital REBOA in the military exercise setting, simulating a modern armed conflict. METHODS: Two adult male Sus Scrofa underwent simulated junctional combat injury in the context of a planned military training exercise. Both underwent zone I REBOA in conjunction with standard tactical combat casualty care interventions-one during point of injury care and the other during en route flight care. Animals were sequentially evacuated to two separate forward surgical teams by rotary wing platform where the balloon position was confirmed by chest x-ray. Animals then underwent different damage control thoracic and abdominal procedures before euthanasia. RESULTS: The first swine underwent immediate successful REBOA at the point of injury 7 minutes and 30 seconds after the injury. It required 6 minutes total from initiation of procedure to effective aortic occlusion. Total occlusion time was 60 minutes. In the second animal, the REBOA placement procedure was initiated immediately after take off (17 minutes and 40 seconds after the injury). Although the movements and vibration of flight were not significant impediments, we only succeeded to put a 6-French (Fr) sheath into a femoral artery during the 14 minutes flight due to lighting and visualization challenges. After the sheath had been upsized in the forward surgical team, the REBOA catheter was primarily placed in zone I followed by its replacement to zone III. Both animals survived to study completion and the termination of training. No complications were observed in either animal. CONCLUSION: Our study demonstrates the potential feasibility of REBOA for use during tactical field and en route (flight) care of combat casualties. Further study is needed to determine the optimal training and utilization protocols required to facilitate the effective incorporation of REBOA into military prehospital care capabilities.

Contributions of the surgeon Nikolai Korotkov (1874-1920) to the management of extremity vascular injury.

The Russian military surgeon Nikolai Korotkov is known worldwide, mainly among internists and cardiovascular specialists, as the discoverer of the auscultatory method of measuring arterial blood pressure in 1905. This article reveals him as one of the first military vascular surgeons to carefully investigate, analyze, and register cases of vascular injury during his voluntarily trips to the Russian Far East in 1900 to 1901 and the Russo-Japanese War of 1904 to 1905. Examining 44 patients with extremity arterial and arterial-venous pseudoaneurysms following war-related injury, he routinely performed a measure termed the "arterial pressure index" using "Korotkov sounds." This pioneering approach to assessing extremity perfusion was the precursor to the modern-day ankle-brachial and injured extremity indices, and it initiated the quantitative assessment of the compensatory ability of the vascular system to restore circulation following axial artery ligation. Because of high thrombosis rates following direct vessel repair during his day, he proposed use of pharmacologic substances such as digitalis and amyl nitrite to improve extremity perfusion. As evidence of his innovative nature, Korotkov even proposed the use of "oxygenated nutrient solutions" in the future to improve extremity circulation. More than 100 years after his work, as continuous wave Doppler ultrasound, contrast angiography, and computed tomography are ubiquitous as diagnostic tools, the practice of surgery would be well served to recall Korotkov's foundational work and the rule of thumb for any physician: examine the patient.

Development of an ovine model of occlusive arterial injury for the evaluation of endovascular interventions.

Endovascular intervention for occlusive arterial trauma is becoming more common in clinical practice. The aim of this study is to present an ovine model of extremity arterial injury for use in future endovascular translational research. Animals under general anesthesia had their left superficial femoral artery exposed, which was bluntly injured over a 2-cm section using a hemostat and injection of air. Occlusion was confirmed on angiography and the flow characteristics measured by ultrasonography. Of five animals enrolled, four occluding lesions were created successfully. Post injury, there was a significant reduction in the median (interquartile range) systolic velocity (cm/sec) on the left (injury) compared to the right (control) side (3.5 (0-16.5) vs. 29 (23.8-43.3); p < 0.001). The ovine superficial femoral artery can be used to consistently produce an occlusive lesion that is suitable for use in the future evaluation of endovascular trauma interventions.

The military surgical legacy of Vladimir Oppel (1872-1932).

Vladimir A. Oppel (1872-1932) was a forefather of military trauma systems. As a surgeon in the Russian Army in World War I, Oppel experienced the challenges and inefficiencies associated with caring for large numbers of combat wounded, the inefficiencies he observed leading to unacceptable morbidity and mortality. As a consequence, Oppel envisioned a coordinated sequence of surgical care on the battlefield and developed the concept of "targeted evacuation." In his work, Oppel was among the first to propose the "right operation for the right patient at the right location at the right time." Central to Oppel's precepts were (1) the forward positioning of surgical care close to the point of injury, (2) the development of a reserve of proficient and deployable military surgeons, and (3) the provision of specialized surgery to optimize survival and reduce morbidity. Oppel's teachings were validated during World War II in the performance of the Soviet casualty evacuation system and in all modern wars modern since. Today, nearly 100 years after the work of Vladimir Oppel, the benefits of a coordinated or "targeted" trauma system, working to optimize survival after trauma, are well recognized around the world.