Partial Resuscitative Endovascular Balloon Occlusion Research Articles

Partial Resuscitative Endovascular Balloon Occlusion of the Aorta Aids in the Successful Non-Operative Management of a Life-Threatening Penetrating Liver Injury.

In recent years, isolated non-operative management of penetrating liver injuries has become the standard of care for the hemodynamically stable patient. However, when the patient becomes hemodynamically unstable, adjuncts such as resuscitative endovascular balloon occlusion of the aorta (REBOA) deployed in Zone 1 can be used to achieve complete aortic occlusion from the celiac axis down. Unfortunately, hemorrhage control through REBOA comes at the risk of deadly intra-abdominal ischemia. Partial REBOA (pREBOA) introduces the opportunity to make targeted changes in volume and thus titrate the amount of aortic occlusion in real-time to adequately manage hemorrhage while allowing some distal blood flow. This is a novel approach and one which may give providers more time to gain definitive hemorrhage control while minimizing the morbidity of ischemia. Here, we present a case of life-threatening penetrating liver injury that was successfully managed non-operatively with the assistance of p-REBOA.

Automated partial resuscitative endovascular balloon occlusion of the aorta reduces blood loss and hypotension in a highly lethal porcine liver injury model.

Partial and intermittent resuscitative endovascular balloon occlusion of the aorta (pREBOA and iREBOA, respectively) are lifesaving techniques designed to extend therapeutic duration, mitigate ischemia, and bridge patients to definitive hemorrhage control. We hypothesized that automated pREBOA balloon titration compared with automated iREBOA would reduce blood loss and hypotensive episodes over a 90-minute intervention phase compared with iREBOA in an uncontrolled liver hemorrhage swine model. Twenty-four pigs underwent an uncontrolled hemorrhage by liver transection and were randomized to automated pREBOA (n = 8), iREBOA (n = 8), or control (n = 8). Once hemorrhagic shock criteria were met, controls had the REBOA catheter removed and received transfusions only for hypotension. The REBOA groups received 90 minutes of either iREBOA or pREBOA therapy. Surgical hemostasis was obtained, hemorrhage volume was quantified, and animals were transfused to euvolemia and then underwent 1.5 hours of automated critical care. The control group had significantly higher mortality rate (5 of 8) compared with no deaths in both REBOA groups, demonstrating that the liver injury is highly lethal ( p = 0.03). During the intervention phase, animals in the iREBOA group spent a greater proportion of time in hypotension than the pREBOA group (20.7% [16.2-24.8%] vs. 0.76% [0.43-1.14%]; p < 0.001). The iREBOA group required significantly more transfusions than pREBOA (21.0 [20.0-24.9] mL/kg vs. 12.1 [9.5-13.9] mL/kg; p = 0.01). At surgical hemostasis, iREBOA had significantly higher hemorrhage volumes compared with pREBOA (39.2 [29.7-44.95] mL/kg vs. 24.7 [21.6-30.8] mL/kg; p = 0.04). Partial REBOA animals spent significantly less time at hypotension and had decreased transfusions and blood loss. Both pREBOA and iREBOA prevented immediate death compared with controls. Further refinement of automated pREBOA is necessary, and controller algorithms may serve as vital control inputs for automated transfusion. Therapeutic/Care Management; Level III.

A randomized porcine study of hemorrhagic shock comparing end-tidal carbon dioxide targeted and proximal systolic blood pressure targeted partial resuscitative endovascular balloon occlusion of the aorta in the mitigation of metabolic injury

BackgroundThe definition of partial resuscitative endovascular balloon occlusion of the aorta (pREBOA) is not yet determined and clinical markers of the degree of occlusion, metabolic effects and end-organ injury that are clinically monitored in real time are lacking. The aim of the study was to test the hypothesis that end-tidal carbon dioxide (ETCO2) targeted pREBOA causes less metabolic disturbance compared to proximal systolic blood pressure (SBP) targeted pREBOA in a porcine model of hemorrhagic shock.Materials and methodsTwenty anesthetized pigs (26–35 kg) were randomized to 45 min of either ETCO2 targeted pREBOA (pREBOAETCO2, ETCO2 90–110% of values before start of occlusion, n = 10) or proximal SBP targeted pREBOA (pREBOASBP, SBP 80–100 mmHg, n = 10), during controlled grade IV hemorrhagic shock. Autotransfusion and reperfusion over 3 h followed. Hemodynamic and respiratory parameters, blood samples and jejunal specimens were analyzed.ResultsETCO2 was significantly higher in the pREBOAETCO2 group during the occlusion compared to the pREBOASBP group, whereas SBP, femoral arterial mean pressure and abdominal aortic blood flow were similar. During reperfusion, arterial and mesenteric lactate, plasma creatinine and plasma troponin concentrations were higher in the pREBOASBP group.ConclusionsIn a porcine model of hemorrhagic shock, ETCO2 targeted pREBOA caused less metabolic disturbance and end-organ damage compared to proximal SBP targeted pREBOA, with no disadvantageous hemodynamic impact. End-tidal CO2 should be investigated in clinical studies as a complementary clinical tool for mitigating ischemic–reperfusion injury when using pREBOA.

Partial vs Full Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) in a Swine Model of Raised Intracranial Pressure and Hemorrhagic Shock.

Partial resuscitative endovascular balloon occlusion of the aorta (pREBOA) is a potential method to mitigate the ischemia observed in full REBOA (fREBOA). However, the effect of pREBOA on cerebral perfusion in the setting of raised intracranial pressure (rICP) is unknown. The aim was to evaluate the effects of no REBOA (nREBOA) vs pREBOA vs fREBOA on cerebral perfusion in a swine model of rICP and hemorrhagic shock. Anesthetized swine (n = 18) underwent instrumentation. Controlled hemorrhage was performed over 30 minutes. rICP was achieved using an intracranial Fogarty catheter inflated to achieve an ICP of 20 mmHg. Animals underwent intervention for 30 minutes, followed by resuscitation. The primary outcome was cerebral perfusion measured by ICP (millimeters of mercury), cerebral perfusion pressure (CPP; millimeters of mercury), and cerebral blood flow (CBF; milliliters per minute per 100 g) derived from CT perfusion. The secondary outcomes included hemodynamics and lactate (millimoles per liter). The peak ICP of pREBOA animals (22.7 ± 2.5) was significantly lower than nREBOA and fREBOA. pREBOA CPP was significantly higher compared with nREBOA and fREBOA during resuscitation. The pREBOA CBF was greater during intervention and resuscitation compared with nREBOA (p < 0.001). Systolic blood pressure was similar between pREBOA and fREBOA, and coronary perfusion was significantly greater in pREBOA. fREBOA had significantly higher lactate during the intervention (9.3 ± 1.3) and resuscitation (8.9 ± 3.5) compared with nREBOA and pREBOA. pREBOA produced greater cerebral perfusion, as demonstrated by more favorable CPP, CBF, and ICP values. fREBOA was associated with metabolic derangement and diminished pressure during resuscitation. pREBOA is superior to fREBOA in a swine model and should be considered over fREBOA for aortic occlusion.

Partial Resuscitative Endovascular Balloon Occlusion of the Aorta Limits Ischemia-Reperfusion Injury After Simulated Aeromedical Evacuation

IntroductionOne of the advantages of partial Resuscitative Endovascular Balloon Occlusion of the Aorta (pREBOA) compared to the original model is the mitigation of reperfusion injury. The safety and efficacy of pREBOA have not been demonstrated in the setting of aeromedical evacuation. We hypothesized that the pREBOA would result in less ischemia-reperfusion injury after altitude exposure. MethodsTwenty-four swine underwent femur fracture with hemorrhage for 20 min, followed by resuscitative endovascular balloon occlusion of the aorta (REBOA) deployment to Zone 1 and were randomized to pREBOA-PRO (Prytime Medical Devices Inc) full inflation, partial inflation, or sham inflation and then an altitude exposure of ground level or 8000 ft for 15 min. The primary endpoint was to examine if the balloon functioned at altitude. Our secondary endpoint was investigating evidence of ischemia-reperfusion by hemodynamic instability, electrolyte derangements, and acidosis. Comparisons were made by ANOVA. ResultsAfter deflation, the partially inflated group maintained a higher mean arterial pressure (MAP) compared to fully inflated group (P = 0.026). Full REBOA pigs were more tachycardic compared to sham pREBOA at ground (P < 0.001) and this was exacerbated at altitude (P < 0.001). Full REBOA pigs were more acidotic than sham and pREBOA at ground pigs (P = 0.0006 and P = 0.0002, respectively). Altitude increased the acidosis in full REBOA pigs, resulting in a greater base deficit (P < 0.0001), lactate (P < 0.0001), and IL-6 (P = 0.006). ConclusionsPREBOA resulted in less severe ischemia-reperfusion injury at both altitude and ground, while full balloon inflation at altitude exacerbated acidosis and ischemia-reperfusion injury. Efforts should therefore be made to utilize partial balloon occlusion when employing the REBOA catheter.

Noninvasive Monitoring of Metabolism and Hemodynamics Using Super-Continuum Infrared Spectroscopy of a Cytochrome C Oxidase (SCISCCO) Instrument

We present a novel, noninvasive, super-continuum infrared spectroscopy of cytochrome c oxidase (SCISCCO) system for simultaneously measuring hemodynamic and metabolic parameters, and we demonstrate its utility by applying it to lab calibration tests, human studies, and swine animal studies. The system optically assays the redox state of cytochrome c oxidase (CCO), as well as traditional markers including oxygenated (HbO) and deoxygenated (HbR) hemoglobin. To demonstrate in vivo feasibility, the measured responses of oxygenation and CCO responses to acute ischemia on the arm and forehead in human participants are compared to data from the literature. The validated SCISCCO system is then applied in human studies to measure cerebral oxygenation and the redox state of CCO in participants during an attention test protocol. We show that the redox state of CCO and hemodynamics measured by the SCISCCO system are consistent with the physiological hypothesis established in prior studies. To enable use of the SCISCCO system in laboratory and hospital settings as well as transportation to remote locations, a cart-based SCISCCO prototype system has also been developed. The cart-based SCISCCO prototype is applied to swine animal models undergoing induction of hemorrhagic shock followed by partial resuscitative endovascular balloon occlusion of the aorta (pREBOA). The pilot study demonstrates the feasibility of using the SCISCCO instrument within the context of existing protocols and validates the instrument’s measurements against the physiological and hemodynamic parameters measured by other conventional devices.

Complete and Partial Resuscitative Endovascular Balloon Occlusion of the Aorta for Hemorrhagic Shock.

Resuscitative endovascular balloon occlusion of the aorta (REBOA) devices grew out of a military-civilian partnership to develop new capabilities for hemorrhage control. With the advent of purpose-built devices, REBOA has become increasingly common in civilian trauma and acute care settings. Currently available REBOA catheters were designed as complete aortic occlusion devices. However, the therapeutic window for complete aortic occlusion is time-limited due to ischemia-reperfusion injury. The partial procedure allows blood flow past the level of occlusion while maintaining targeted proximal pressure, which has been shown to reduce distal ischemia and adjunctive resuscitation requirements in preclinical studies with prolonged occlusion times as compared to traditional complete occlusion. pREBOA-PRO is the first catheter designed to enable partial and complete aortic occlusion and is currently in limited market release at seven Level I trauma centers in North America. This paper will focus on procedural considerations for REBOA, including patient selection criteria and a comparison of complete and partial aortic occlusion in a simulator, along with highlighting critical steps to improve clinical outcomes. Additionally, this paper reviews a contrast-enhanced CT scan from a trauma patient that shows distal perfusion after 2 h of partial aortic occlusion using this newly designed catheter and discusses representative results from the limited market release to highlight the profound effect of technological innovation on outcomes in vascular emergencies.

Complete and Partial Resuscitative Endovascular Balloon Occlusion of the Aorta for Hemorrhagic Shock

Resuscitative endovascular balloon occlusion of the aorta (REBOA) devices grew out of a military-civilian partnership to develop new capabilities for hemorrhage control. With the advent of purpose-built devices, REBOA has become increasingly common in civilian trauma and acute care settings. Currently available REBOA catheters were designed as complete aortic occlusion devices. However, the therapeutic window for complete aortic occlusion is time-limited due to ischemia-reperfusion injury. The partial procedure allows blood flow past the level of occlusion while maintaining targeted proximal pressure, which has been shown to reduce distal ischemia and adjunctive resuscitation requirements in preclinical studies with prolonged occlusion times as compared to traditional complete occlusion. pREBOA-PRO is the first catheter designed to enable partial and complete aortic occlusion and is currently in limited market release at seven Level I trauma centers in North America. This paper will focus on procedural considerations for REBOA, including patient selection criteria and a comparison of complete and partial aortic occlusion in a simulator, along with highlighting critical steps to improve clinical outcomes. Additionally, this paper reviews a contrast-enhanced CT scan from a trauma patient that shows distal perfusion after 2 h of partial aortic occlusion using this newly designed catheter and discusses representative results from the limited market release to highlight the profound effect of technological innovation on outcomes in vascular emergencies.

The physiology of aortic flow and pressures during partial resuscitative endovascular balloon occlusion of the aorta in a swine model of hemorrhagic shock

Partial resuscitative endovascular balloon occlusion of the aorta (REBOA) has shown promise as a method to extend REBOA, but there lacks a standard definition of the technique. The purpose of this study was to investigate the relationships between distal and proximal mean arterial pressure (MAP) and distal aortic flow past a REBOA catheter. We hypothesize that a relationship between distal aortic flow and distal MAP in Zone 1 partial REBOA (pREBOA) is conserved and that there is no apparent relationship between aortic flow and proximal MAP. A retrospective data analysis of swine was performed. Cohort 1 underwent 20% controlled hemorrhage and then randomized to aortic flow of 400 mL/min or complete occlusion for 20 minutes (n = 11). Cohort 2 underwent 30% controlled hemorrhage followed by complete aortic occlusion for 30 minutes (n = 29). Then, they all underwent REBOA wean in a similar stepwise fashion. Blood pressure was collected from above (proximal) and below (distal) the REBOA balloon. Aortic flow was measured using a surgically implanted supraceliac aortic perivascular flow probe. The time period of balloon wean was taken as the time point of interest. A linear relationship between distal MAP and aortic flow was observed ( R2 value, 0.80), while no apparent relationship appeared between proximal MAP and aortic flow ( R2 value, 0.29). The repeated-measures correlation coefficient for distal MAP (0.94; 95% confidence interval, 0.94-0.94) was greater than proximal MAP (-0.73; 95% confidence interval, -0.74 to -0.72). The relationship between MAP and flow will be a component of next-generation pREBOA control inputs. This study provides evidence that pREBOA techniques should rely on distal rather than proximal MAP for control of distal aortic flow. These data could inform future inquiry into optimal flow rates and parameters based on distal MAP in both translational and clinical contexts.

Targeted Regional Optimization in Action: Dose-dependent End-organ Ischemic Injury with Partial Aortic Occlusion in the Setting of Ongoing Liver Hemorrhage.

Targeted regional optimization (TRO) describes partial resuscitative endovascular balloon occlusion of the aorta strategy that allows for controlled distal perfusion to balance hemostasis and tissue perfusion. This study characterized hemodynamics at specific targeted distal flow rates in a swine model of uncontrolled hemorrhage to determine if precise TRO by volume was possible. Anesthetized swine were subjected to liver laceration and randomized into TRO at distal flows of 300 mL/min (n = 8), 500 mL/min (n = 8), or 700 mL/min (n = 8). After 90 min, the animals received damage control packing and were monitored for 6 h. Hemodynamic parameters were measured continuously, and hematology and serologic labs obtained at predetermined intervals. During TRO, the average percent deviation from the targeted flow was lower than 15.9% for all cohorts. Average renal flow rates were significantly different across all cohorts during TRO phase (P < 0.0001; TRO300 = 63.1 ± 1.2; TRO500 = 133.70 ± 1.93; TRO700 = 109.3 ± 2.0), with the TRO700 cohort having less renal flow than TRO500. The TRO500 and TRO700 average renal flow rates inverted during the intensive care unit phase (P < 0.0001; TRO300 = 86.20 ± 0.40; TRO500 = 148.50 ± 1.45; TRO700 = 181.1 ± 0.70). There was higher blood urea nitrogen, creatinine, and potassium in the TRO300 cohort at the end of the experiment, but no difference in lactate or pH between cohorts. This study demonstrated technical feasibility of TRO as a strategy to improve outcomes after prolonged periods of aortic occlusion and resuscitation in the setting of ongoing solid organ hemorrhage. A dose-dependent ischemic end-organ injury occurs beginning with partial aortic occlusion that progresses through the critical care phase, with exaggerated effect on renal function.

Advanced partial occlusion controller allows for increased precision during targeted regional optimization in a porcine model of hemorrhagic shock.

Targeted regional optimization (TRO), a partial resuscitative endovascular balloon occlusion of the aorta strategy, may mitigate distal ischemia and extend the window of effectiveness for this adjunct. An automated device may allow greater control and precise regulation of flow past the balloon, while being less resource-intensive. The objective of this study was to assess the technical feasibility of the novel advanced partial occlusion controller (APOC) in achieving TRO at multiple distal pressures. Female swine (n = 48, 68.1 ± 0.7 kg) were randomized to a target distal mean arterial pressure (MAP) of 25 mm Hg, 35 mm Hg, or 45 mm Hg by either manual (MAN) or APOC regulation (n = 8 per group). Uncontrolled hemorrhage was generated by liver laceration. Targeted regional optimization was performed for 85 minutes, followed by surgical control and a 6-hour critical care phase. Proximal and distal MAP and flow rates were measured continuously. At a target distal MAP of 25 mm Hg, there was no difference in the MAP attained (APOC: 26.2 ± 1.05 vs. MAN: 26.1 ± 1.78 mm Hg) but the APOC had significantly less deviance (10.9%) than manual titration (14.9%, p < 0.0001). Similarly, at a target distal MAP of 45 mm Hg, there was no difference in mean pressure (44.0 ± 0.900 mm Hg vs. 45.2 ± 1.31 mm Hg) but APOC had less deviance (9.34% vs. 11.9%, p < 0.0001). There was no difference between APOC and MAN in mean (34.6 mm Hg vs. 33.7 mm Hg) or deviance (9.95% vs. 10.4%) at a target distal MAP of 35 mm Hg, respectively. The APOC made on average 77 balloon volume adjustments per experiment compared with 29 by manual titrations. The novel APOC consistently achieved and sustained precisely regulated TRO across all groups and demonstrated reduced deviance at the 25 mm Hg and 45 mm Hg groups compared with manual titration.

End-tidal Carbon Dioxide as an Indicator of Partial REBOA and Distal Organ Metabolism in Normovolemia and Hemorrhagic Shock in Anesthetized Pigs.

It is difficult to estimate the ischemic consequences when using partial resuscitative endovascular balloon occlusion of the aorta (REBOA). The aim was to investigate if end-tidal carbon dioxide (ETCO2) is correlated to degree of aortic occlusion, measured as distal aortic blood flow, and distal organ metabolism, estimated as systemic oxygen consumption (VO2), in a porcine model of normovolemia and hemorrhagic shock. Nine anesthetized pigs (25-32 kg) were subjected to incremental steps of zone 1 aortic occlusion (reducing distal aortic blood flow by 33%, 66%, and 100%) during normovolemia and hemorrhagic grade IV shock. Hemodynamic and respiratory variables, and blood samples, were measured. Systemic VO2 was correlated to ETCO2 and measures of partial occlusion previously described. Aortic occlusion gradually lowered distal blood flow and pressure, whereas ETCO2, VO2 and carbon dioxide production decreased at 66% and 100% aortic occlusion. Aortic blood flow correlated significantly to ETCO2 during both normovolemia and hemorrhage (R = 0.84 and 0.83, respectively) and to femoral mean pressure (R = 0.92 and 0.83, respectively). Systemic VO2 correlated strongly to ETCO2 during both normovolemia and hemorrhage (R = 0.91 and 0.79, respectively), blood flow of the superior mesenteric artery (R = 0.77 and 0.85, respectively) and abdominal aorta (R = 0.78 and 0.78, respectively), but less to femoral blood pressure (R = 0.71 and 0.54, respectively). ETCO2 was correlated to distal aortic blood flow and VO2 during incremental degrees of aortic occlusion thereby potentially reflecting the degree of aortic occlusion and the ischemic consequences of partial REBOA. Further studies of ETCO2, and potential confounders, in partial REBOA are needed before clinical use.

Is cerebral perfusion maintained during full and partial resuscitative endovascular balloon occlusion of the aorta in hemorrhagic shock conditions?

Partial resuscitative endovascular balloon occlusion of the aorta (pREBOA) is a technology that occludes aortic flow and allows for controlled deflation and restoration of varying distal perfusion. Carotid flow rates (CFRs) during partial deflation are unknown. Our aim was to measure CFR with the different pREBOA balloon volumes and correlate those to the proximal mean arterial pressure (PMAP) and a handheld pressure monitoring device (COMPASS; Mirador Biomedical, Seattle, WA). Ten swine underwent a hemorrhagic injury model with carotid and iliac arterial pressures monitored via arterial lines. Carotid and aortic flow rates were monitored with Doppler flow probes. A COMPASS was placed to monitor proximal pressure. The pREBOA was inflated for 15 minutes then partially deflated for an aortic flow rate of 0.7 L/min for 45 minutes. It was then completely deflated. Proximal mean arterial pressures and CFR were measured, and correlation was evaluated. Correlation between CRF and COMPASS measurements was evaluated. Carotid flow rate increased 240% with full inflation. Carotid flow rate was maintained at 100% to 150% of baseline across a wide range of partial deflation. After full deflation, CFR transiently decreased to 45% to 95% of baseline. There was strong positive correlation (r > 0.85) between CFR and PMAP after full inflation, and positive correlation with partial inflation (r > 0.7). Carotid flow rate had strong correlation with the COMPASS with full REBOA (r > 0.85) and positive correlation with pREBOA (r > 0.65). Carotid flow rate is increased in a hemorrhagic model during full and partial inflation of the pREBOA and correlates well with PMAP. Carotid perfusion appears maintained across a wide range of pREBOA deflation and could be readily monitored with a handheld portable COMPASS device instead of a standard arterial line setup.

Real-time bedside management and titration of partial resuscitative endovascular balloon occlusion of the aorta without an arterial line: Good for pressure, not for flow!

Partial resuscitative endovascular balloon occlusion of the aorta (pREBOA) attempts to minimize ischemia/reperfusion injury while controlling hemorrhage. There are little data on optimal methods to evaluate and titrate partial flow, which typically requires invasive arterial line monitoring. We sought to examine the use of a miniaturized handheld digital pressure device (COMPASS; Mirador Biomedical, Seattle, WA) for pREBOA placement and titration of flow. Ten swine underwent standardized hemorrhagic shock. Carotid and iliac pressures were monitored with both arterial line and COMPASS devices, and flow was monitored by aortic and superior mesenteric artery flow probes. Partial resuscitative endovascular balloon occlusion of the aorta was inflated to control hemorrhage for 15 minutes before being deflated to try targeting aortic flow of 0.7 L/min (using only the COMPASS device) by an operator blinded to the arterial line pressures and aortic flow. Correlations between COMPASS and proximal/distal arterial line were evaluated, as well as actual aortic flow. There was strong correlation between the distal mean arterial pressure (MAP) and the distal COMPASS MAP (r = 0.979, p < 0.01), as well as between the proximal arterial line and the proximal COMPASS on the pREBOA (r = 0.989, p < 0.01). There was a significant but weaker correlation between the distal compass MAP reading and aortic flow (r = 0.47, p < 0.0001), although it was not clinically significant and predicted flow was not achieved in a majority of the procedures. Of 10 pigs, survival times ranged from 10 to 120 minutes, with a mean survival of 50 minutes, and 1 pig surviving to 120 minutes. Highly reliable pressure monitoring is achieved proximally and distally without arterial lines using the COMPASS device on the pREBOA. Despite accurate readings, distal MAPs were a poor indicator of aortic flow, and titration based upon distal MAPs did not provide reliable results. Further investigation will be required to find a suitable proxy for targeting specific aortic flow levels using pREBOA.

Automated Partial Versus Complete Resuscitative Endovascular Balloon Occlusion of the Aorta for the Management of Hemorrhagic Shock in a Pig Model of Polytrauma: a Randomized Controlled Pilot Study.

Endovascular variable aortic control (EVAC) is an automated partial resuscitative endovascular balloon occlusion of the aorta (REBOA) platform designed to mitigate the deleterious effects of complete REBOA. Long-term experiments are needed to assess potential benefits. The feasibility of a 24-hour experiment in a complex large animal trauma model remains unknown. Anesthetized swine were subjected to controlled hemorrhage, blunt thoracic trauma, and tibial fractures. Animals were then randomized (N=3/group) to control (No balloon support), 90minutes of complete supraceliac REBOA, or 10minutes of supraceliac REBOA followed by 80minutes of EVAC. One hundred ten minutes after injury, animals were resuscitated with shed blood, the REBOA catheter was removed. Automated critical care under general anesthesia was maintained for 24hours. Animals in the control and EVAC groups survived to the end of the experiment. Animals in the REBOA group survived for 120, 130, and 660minutes, respectively. Animals in the EVAC group displayed similar mean arterial pressure and plasma lactate concentration as the control group by the end of the experiment. Histologic analysis suggested myocardial injury in the REBOA group when compared with controls. This study demonstrates the feasibility of intermediate-term experiments in a complex swine model of polytrauma with 90minutes of REBOA. EVAC may be associated with improved survival at 24hours when compared with complete REBOA. EVAC resulted in normalized physiology after 24hours, suggesting that prolonged partial occlusion is possible. Longer studies evaluating partial REBOA strategies are needed.

A New Pressure-Regulated, Partial Resuscitative Endovascular Balloon Occlusion of the Aorta Device Achieves Targeted Distal Perfusion

BackgroundResuscitative endovascular balloon occlusion of the aorta (REBOA) reduces blood loss and improves hemodynamics. Complete occlusion results in distal ischemia, limiting its use for prolonged care. This study evaluated two next-generation partial REBOA (pREBOA) catheters and their ability to achieve targeted distal aortic flow. Materials and methodsSwine underwent hemorrhagic shock, complete aortic occlusion, controlled continuous balloon deflation, and targeted distal perfusion (TDP; 300-mL/min) phases. They were randomized into three groups (n = 6/group), one managed with the current ER-REBOA (ER), and two with the new pREBOA technologies: a bilobed (BL) device and a semicompliant pREBOA-PRO (PRP). Hemodynamics including flow rates and mean arterial pressures at the carotid artery and infrarenal aorta were recorded. ResultsHemodynamics were comparable between groups during hemorrhage and complete occlusion phases. During the controlled continuous balloon deflation phase, the distal aortic flow rate strongly correlated with percent balloon volume in BL and PRP groups, suggesting a precise control of distal perfusion. The slope of flow-balloon-volume curves was greater in the ER group than BL and PRP groups, indicating the change in distal aortic flow rate was more sensitive to the balloon volume (less titratable) when using ER. During the TDP phase, variation in distal aortic flow and mean arterial pressure with respect to the target flow was lower in ER and PRP groups, than the BL group. ConclusionsPressure-regulated occlusion using the next-generation pREBOA catheters is more controlled than the first-generation ER-REBOA catheter and allow for targeted and precise distal perfusion.

Use of bilobed partial resuscitative endovascular balloon occlusion of the aorta is logistically superior in prolonged management of a highly lethal aortic injury.

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a viable technique for management of noncompressible torso hemorrhage. The major limitation of the current unilobed fully occlusive REBOA catheters is below-the-balloon ischemia-reperfusion complications. We hypothesized that partial aortic occlusion with a novel bilobed partial (p)REBOA-PRO would result in the need for less intraaortic balloon adjustments to maintain a distal goal perfusion pressure as compared with currently available unilobed ER-REBOA. Anesthetized (40-50 kg) swine randomized to control (no intervention), ER-REBOA, or pREBOA-PRO underwent supraceliac aortic injury. The REBOA groups underwent catheter placement into zone 1 with initial balloon inflation to full occlusion for 10 minutes followed by gradual deflation to achieve and subsequently maintain half of the baseline below-the-balloon mean arterial pressure (MAP). Physiologic data and blood samples were collected at baseline and then hourly. At 4 hours, the animals were euthanized, total blood loss and urine output were recorded, and tissue samples were collected. Baseline physiologic data and basic laboratories were similar between groups. Compared with control, interventions similarly prolonged survival from a median of 18 minutes to over 240 minutes with comparable mortality trends. Blood loss was similar between partial ER-REBOA (41%) and pREBOA-PRO (51%). Partial pREBOA-PRO required a significantly lower number of intraaortic balloon adjustments (10 ER-REBOA vs. 3 pREBOA-PRO, p < 0.05) to maintain the target below-the-balloon MAP. The partial ER-REBOA group developed significantly increased hypercapnia, fibrin clot formation on TEG, liver inflammation, and IL-10 expression compared with pREBOA-PRO. In this highly lethal aortic injury model, use of bilobed pREBOA-PRO for a 4-hour partial aortic occlusion was logistically superior to unilobed ER-REBOA. It required less intraaortic balloon adjustments to maintain target MAP and resulted in less inflammation.

A new, pressure-regulated balloon catheter for partial resuscitative endovascular balloon occlusion of the aorta.

A new, pressure-regulated balloon catheter for partial resuscitative endovascular balloon occlusion of the aorta.

Validation of a novel partial resuscitative endovascular balloon occlusion of the aorta device in a swine hemorrhagic shock model: Fine tuning flow to optimize bleeding control and reperfusion injury.

Partial restoration of aortic flow during resuscitative endovascular balloon occlusion of the aorta (REBOA) is advocated by some to mitigate distal ischemia. Our laboratory has validated the mechanics and optimal partial REBOA (pREBOA) flow rates using a prototype device. We hypothesize that pREBOA will increase survival when compared with full REBOA (fREBOA) in prolonged nonoperative management of hemorrhagic shock. Twenty swine underwent placement of aortic flow probes, zone 1 REBOA placement, and 20% blood volume hemorrhage. They were randomized to either solid organ or abdominal vascular injury. The pREBOA arm (10 swine) underwent full inflation for 10 minutes and then deflation to a flow rate of 0.5 L/min for 2 hours. The fREBOA arm (10 swine) underwent full inflation for 60 minutes, followed by deflation/resuscitation. The primary outcome is survival, and secondary outcomes are serologic/pathologic signs of ischemia-reperfusion injury and quantity of hemorrhage. Two of 10 swine survived in the fREBOA group (2/5 solid organ injury; 0/5 abdominal vascular injury), whereas 7 of 10 swine survived in the pREBOA group (3/5 solid organ injury, 4/5 abdominal vascular injury). Survival was increased (p = 0.03) and hemorrhage was higher in the pREBOA group (solid organ injury, 1.36 ± 0.25 kg vs. 0.70 ± 0.33 kg, p = 0.007; 0.86 ± 0.22 kg vs. 0.71 ± 0.28 kg, not significant). Serum evidence of ischemia was greater with fREBOA, but this was not significant (e.g., lactate, 16.91 ± 3.87 mg/dL vs. 12.96 ± 2.48 mg/dL at 120 minutes, not significant). Swine treated with pREBOA that survived demonstrated trends toward lower alanine aminotransferase, lower potassium, and higher calcium. The potassium was significantly lower in survivors at 60 minutes and 90 minutes time points (5.97 ± 0.60 vs. 7.53 ± 0.90, p = 0.011; 6.67 ± 0.66 vs. 8.15 ± 0.78, p = 0.029). Calcium was significantly higher at 30 minutes, 60 minutes, and 90 minutes (8.56 ± 0.66 vs. 7.50 ± 0.40, p = 0.034; 8.63 ± 0.62 vs. 7.15 ± 0.49, p = 0.019; 8.96 ± 0.64 vs. 7.00, p = 0.028). Prolonged pREBOA at a moderate distal flow rate provided adequate hemorrhage control, improved survival, and had evidence of decreased ischemic injury versus fREBOA. Prophylactic aggressive calcium supplementation may have utility before and during the reperfusion phase.

Organ ischemia during partial resuscitative endovascular balloon occlusion of the aorta: Dynamic 4D Computed tomography in swine

Resuscitative endovascular balloon occlusion of the aorta (REBOA) increases proximal pressure, and simultaneously induces distal ischemia. We aimed to evaluate organ ischemia during partial REBOA (P-REBOA) with computed tomography (CT) perfusion in a swine model. The maximum balloon volume was recorded as total REBOA when the distal pulse pressure ceased. The animals (n = 4) were scanned at each 20% of the maximum balloon volume, and time-density curve (TDC) were analysed at the aorta, portal vein (PV), liver parenchyma, and superior mesenteric vein (SMV, indicating mesenteric perfusion). The area under the TDC (AUTDC), the time to peak (TTP), and four-dimensional volume-rendering images (4D-VR) were evaluated. The TDC of the both upper and lower aorta showed an increased peak and delayed TTP. The TDC of the PV, liver, and SMV showed a decreased peak and delayed TTP. The dynamic 4D-CT analysis suggested that organ perfusion changes according to balloon volume. The AUTDC at the PV, liver, and SMV decreased linearly with balloon inflation percentage to the maximum volume. 4D-VR demonstrated the delay of the washout in the aorta and retrograde flow at the inferior vena cava in the highly occluded status.