Induced Moderate Hypothermia in Aortic Rupture With Retroperitoneal Bleeding: A Randomized Porcine Study.

OBJECTIVE: Induced hypothermia improves outcome in aortic arch surgery, neonatal neurointensive care, and transplant surgery for example. In contrast, spontaneous hypothermia has been associated with worse outcomes in patients suffering from hemorrhagic shock, mostly explained by its adverse effects on the coagulation system. We investigated if induced hypothermia would impair short-term survival in experimental aortic rupture with retroperitoneal bleeding. METHODS: Anesthetized pigs were randomized into 2 groups: hypothermia by peritoneal lavage of ice-cold Ringer's acetate and external cooling (n = 10) and normothermia (n = 10). Aortic rupture with retroperitoneal bleeding was induced by endovascular means creating a 6 mm hole in the retroperitoneal portion of abdominal aorta. Survival (primary outcome), hemodynamics, and arterial blood gases including lactate were collected and analyzed up to 180 min after aortic rupture. RESULTS: The body temperature (mean ± standard deviation) in the hypothermic group was 31.5 ± 1.0 °C and 38.7 ± 0.4 °C in the normothermic group at the time for aortic rupture. Survival up to 180 min after the retroperitoneal bleeding was significantly higher in the hypothermic compared with the normothermic group (P = 0.023). CONCLUSIONS: Induced hypothermia did not impair survival in this experimental retroperitoneal aortic bleeding model in anesthetized pigs. This finding may indicate a minor role for the coagulation system in this type of bleeding.

Intestinal Fatty Acid-Binding Protein as a Potential Biomarker for Gastrointestinal Complications after Complex Endovascular Aortic Surgery.

BACKGROUND: This study aimed to investigate the association between intestinal fatty acid-binding protein (I-FABP), acute gastrointestinal injury (AGI) grade, and gastrointestinal (GI) complications after fenestrated or branched endovascular aortic aneurysm repair. METHODS: A total of 17 patients undergoing endovascular aortic repair for thoracoabdominal, juxtarenal, suprarenal, or pararenal aneurysm between May 2017 and September 2018 were enrolled. Blood samples were collected preoperatively and during postoperative intensive care. The blood samples were analyzed for I-FABP with enzyme-linked immunosorbent assay. Gastrointestinal function was assessed according to the AGI grade every day during postoperative intensive care. RESULTS: Higher concentrations of I-FABP at 24 hr and 48 hr correlated to higher AGI grade on postoperative days 1, 2, and 3 (P = 0.032 and P = 0.048, P = 0.040 and P = 0.018, and P = 0.012 and P = 0.016, respectively). Patients who developed a GI complication within 90 days postoperatively had a higher overall AGI grade than those who did not develop a GI complication (P < 0.001), as well as higher concentrations of I-FABP at 48 hrs (P = 0.019). Patients developing GI dysfunction (AGI grade ≥2) had a higher frequency of complications (P = 0.009) and longer length of stay in the intensive care unit (P = 0.008). CONCLUSIONS: In patients undergoing endovascular aortic repair for complex aneurysm increased postoperative plasma I-FABP concentrations and postoperative GI dysfunction, evaluated using the AGI grade, were associated with GI complications, indicating that these measures may be useful in the postoperative management of these patients.

The effect of an endovascular Heaney maneuver to achieve total hepatic isolation on survival, hemodynamic stability, retrohepatic bleeding, and collateral flow in a porcine model.

PURPOSE: Combining resuscitative endovascular balloon occlusion of the aorta (REBOA) and the inferior vena cava (REBOVC) with open surgery is a new hybrid approach for treating retrohepatic vena caval injuries. We compared endovascular total hepatic isolation with supraceliac REBOA ± suprahepatic REBOVC and no occlusion in experimental retrohepatic vena cava bleeding regarding survival, bleeding volume, hemodynamic stability, and arterial collateral blood flow. METHODS: Twenty-five anesthetized pigs (n = 6-7/group) were randomized to REBOA; REBOA + REBOVC; REBOA + infra and suprahepatic REBOVC + portal vein occlusion (endovascular Heaney maneuver, four-balloon-occlusion, 4BO) or no occlusion. After balloon inflation, free bleeding was initiated from an open sheath in the retrohepatic vena cava. Bleeding volume, right internal thoracic artery (RITA) blood flow, hemodynamics, and arterial blood variables were measured until death or up to 90 min. RESULTS: The REBOA group had a longer median survival time (63 min) compared with the 4BO (24 min, P = 0.02) and no occlusion (30 min, P = 0.02) groups, not versus the REBOA + REBOVC group (49 min, P > 0.05). The first 15 min accumulated bleeding was comparable in all groups (P > 0.05); Thereafter, bleeding volume was higher in the REBOA group versus the 4BO group (P < 0.05), not versus the other groups. RITA blood flow and MAP were higher in the REBOA group versus the other groups after 10 min of bleeding (P < 0.05). CONCLUSIONS: Endovascular Heaney maneuver was not beneficial for survival or hemodynamic stability in this porcine model, whereas supraceliac REBOA was. Anatomical differences in thoracoabdominal collaterals between pigs and humans must be considered when interpreting these results.

A 12-year experience of endovascular repair for ruptured abdominal aortic aneurysms in all patients.

OBJECTIVE: Endovascular aneurysm repair (EVAR) has been increasingly performed for ruptured abdominal aortic aneurysms (rAAAs). However, multiple randomized trials have failed to demonstrate a survival benefit compared with open aortic surgery. During a 12-year period, 100% of patients without a history of aneurysm surgery had undergone EVAR for a rAAA at Örebro University Hospital, with no emergent open aortic surgery performed. In the present study, we evaluated the mortality and technical success during this "EVAR-only" period. METHODS: A single-center, retrospective observational study was conducted. We identified all patients who had presented to Örebro University Hospital with a rAAA between October 2009 and September 2021. Patients with isolated iliac artery, thoracic, and thoracoabdominal aortic ruptures were not included. Patients who had received previous aortic interventions (open or endovascular) and patients who had received palliative treatment instead of surgical intervention were also excluded. The patient characteristics, perioperative and postoperative data, and mortality rate were investigated. RESULTS: EVAR had been performed in 100 patients. Preoperative hemodynamic instability had been present in 54 patients (54%), and 18 (18%) had undergone aortic balloon occlusion. The aneurysm location was infrarenal in 89 patients (89%). Bifurcated stent grafts had been used in 97 patients (97%), and adjunct endovascular techniques had been used for 27 patients (27%). Of 98 patients, EVAR had been performed with the patient under local anesthesia for 62 patients (63%). Peri- and postoperative complications at 30 days had occurred in 20 of 100 patients (20%) and 22 of 79 patients (28%), respectively. The overall mortality at 30 days was 27% (27 of 100 patients), and the mortality for those with an isolated infrarenal rAAA was 24% (21 of 89 patients). The overall mortality at 1 year was 39% (39 of 100 patients) and for those with an isolated infrarenal rAAA was 37% (33 of 89 patients). The presence of preoperative hemodynamic instability and the use of ABO were statistically significantly and independently associated with increased 30-day mortality on multivariate logistic regression analysis. CONCLUSIONS: All 100 patients who had undergone surgery for a rAAA had been treated using EVAR and endovascular adjuncts, with a relatively low mortality rate, thus continuing the "EVAR-only" approach. A low proportion of rAAA patients were considered surgically unsuitable. These findings support the applicability of EVAR for the treatment of all rAAAs at suitable centers.

A porcine study of ultrasound-guided versus fluoroscopy-guided placement of endovascular balloons in the inferior vena cava (REBOVC) and the aorta (REBOA).

Objectives: In fluoroscopy-free settings, alternative safe and quick methods for placing resuscitative endovascular balloon occlusion of the aorta (REBOA) and resuscitative endovascular balloon occlusion of the inferior vena cava (REBOVC) are needed. Ultrasound is being increasingly used to guide the placement of REBOA in the absence of fluoroscopy. Our hypothesis was that ultrasound could be used to adequately visualize the suprahepatic vena cava and guide REBOVC positioning, without significant time-delay, when compared with fluoroscopic guidance, and compared with the corresponding REBOA placement. Methods: Nine anesthetized pigs were used to compare ultrasound-guided placement of supraceliac REBOA and suprahepatic REBOVC with corresponding fluoroscopic guidance, in terms of correct placement and speed. Accuracy was controlled by fluoroscopy. Four intervention groups: (1) fluoroscopy REBOA, (2) fluoroscopy REBOVC, (3) ultrasound REBOA and (4) ultrasound REBOVC. The aim was to carry out the four interventions in all animals. Randomization was performed to either fluoroscopic or ultrasound guidance being used first. The time required to position the balloons in the supraceliac aorta or in the suprahepatic inferior vena cava was recorded and compared between the four intervention groups. Results: Ultrasound-guided REBOA and REBOVC placement was completed in eight animals, respectively. All eight had correctly positioned REBOA and REBOVC on fluoroscopic verification. Fluoroscopy-guided REBOA placement was slightly faster (median 14 s, IQR 13-17 s) than ultrasound-guided REBOA (median 22 s, IQR 21-25 s, p=0.024). The corresponding comparisons of the REBOVC groups were not statistically significant, with fluoroscopy-guided REBOVC taking 19 s, median (IQR 11-22 s) and ultrasound-guided REBOVC taking 28 s, median (IQR 20-34 s, p=0.19). Conclusion: Ultrasound adequately and quickly guide the placement of supraceliac REBOA and suprahepatic REBOVC in a porcine laboratory model, however, safety issues must be considered before use in trauma patients. Level of evidence: Prospective, experimental, animal study. Basic science study.

Detection and isolation of intestinal muscle relaxant substances from the root of Taverniera abyssinica A. Rich.

ETHNOPHARMACOLOGICAL RELEVANCE: In Ethiopian traditional medicine the root of Taverniera abyssinica A.Rich is known as a remedy for sudden gastrointestinal cramping and fever. In this study we have isolated and identified the bioactive principle of Taverniera abyssinica that exerts effects on isolated smooth muscle tissues of the rabbit duodenum and guinea-pig ileum. AIM OF THE STUDY: To isolate and purify the bioactive principle from the root of Taverniera abyssinica A.Rich by bioassay-guided fractionation, HPLC purification and masspectrometry, with further investigation of its bioactivity on isolated smooth muscle strips. MATERIALS AND METHODS: Roots of Taverniera abyssinica A.Rich extracted in 75% methanol/water were fractioned with a reverse phase column and then subjected to HPLC purification. Each fraction collected from the HPLC was tested for its bioactivity using electric field stimulation-evoked contractions of the rabbit duodenum and guinea-pig ileum. Finally, detailed structural analysis of the fraction displaying significant bioactivity was made by mass spectrometry. RESULTS: Through bioassay-guided fractionation and HPLC purification the bioactive fractions were identified. These were tested for bioactivity on isolated smooth muscle strips which showed about 80% inhibition of contractions evoked by electric field stimulation. These compounds were identified as formononetin, afrormosin and tectorigenin by using masspectrometry applying relevant standards for detection. CONCLUSION: The traditionally claimed smooth muscle-relaxing effect of the roots of Taverniera abyssinica A.Rich is essentially due the three isolated and purified the two isoflavones formononetin, afrormosin as well as the metoxyisoflavone tectorigenin, along with possibly other not yet purified bioactive substances, however with similar smooth muscle-relaxing properties.

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.

BACKGROUND: The 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 METHODS: Twenty 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. RESULTS: ETCO2 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. CONCLUSIONS: In 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.

Intra-aortic and Intra-caval Balloon Pump Devices in Experimental Non-traumatic Cardiac Arrest and Cardiopulmonary Resuscitation.

Intra-aortic balloon pump (IABP) use during CPR has been scarcely studied. Intra-caval balloon pump (ICBP) may decrease backward venous flow during CPR. Mechanical chest compressions (MCC) were initiated after 10 min of cardiac arrest in anesthetized pigs. After 5 min of MCC, IABP (n = 6) or ICBP (n = 6) was initiated. The MCC device and the IABP/ICBP had slightly different frequencies, inducing a progressive peak pressure phase shift. IABP inflation 0.15 s before MCC significantly increased mean arterial pressure (MAP) and carotid blood flow (CBF) compared to inflation 0.10 s after MCC and to MCC only. Coronary perfusion pressure significantly increased with IABP inflation 0.25 s before MCC compared to inflation at MCC. ICBP inflation before MCC significantly increased MAP and CBF compared to inflation after MCC but not compared to MCC only. This shows the potential of IABP in CPR when optimally synchronized with MCC. The effect of timing of intra-aortic balloon pump (IABP) inflation during mechanical chest compressions (MCC) on hemodynamics. Data from12 anesthetized pigs.

NO-Donation Increases Visceral Circulation in a Porcine Model of Abdominal Hypertension.

Intraabdominal hypertension (IAH) is negative for outcome after intensive care. Little research has focused on medical intervention to improve visceral circulation during IAH. A nitric oxide (NO)-donor was compared with placebo in 25 pigs; each pig was randomized into three groups: PDNO (NO-donor), Control (placebo), or Sham. IAH was induced by CO2 insufflation to 30 mmHg. Sham group had surgical preparation only. Blood gases, invasive venous and arterial blood pressure, intestinal microcirculation and superior mesenteric blood flow were measured. The PDNO group had significantly increased intestinal microcirculation compared with Controls during IAH (last hour, P = 0.009). The mean arterial pressure and abdominal perfusion pressures (APP) were decreased, and the cardiac index were increased in the PDNO group. Also, systemic and pulmonary vascular resistances were lower in the PDNO group compared with Controls. These experimental findings indicate that NO should be further explored with potential application to improve intestinal microcirculation in IAH patients.

Fully covered self-expandable metal stent placed over a stapled colon anastomosis in an animal model: A pilot study of colon metabolism over the stent.

Background and Aim: Anastomotic leakage (AL) in colorectal resection and primary anastomosis is a common and feared complication. Fully covered self-expandable metal stents (FCSEMSs) have been used for the treatment of AL. It is still unknown whether FCSEMSs affect anastomosis healing negatively by causing ischemia. In an animal study, we investigated the metabolic effects over a FCSEMS covering a stapled colon anastomosis. Methods: Seven pigs were investigated using microdialysis after laparotomy, colon resection, and anastomosis with stent placement. Measurements were done at the proximal and distal ends of the anastomosis and at a reference catheter placed at the small intestine. Measurements of glucose, pyruvate, lactate, glycerol, and the lactate/pyruvate ratio (L/P) were carried out. Results: Lactate and L/P were significantly higher at the oral part of the anastomosis, while glucose showed a small declining tendency. At the distal part of the anastomosis, glucose decreased significantly after the resection but did not reach zero. Lactate increased significantly whereas L/P increased only slightly. Glycerol levels were stable. Conclusion: Colon resection caused initially hypermetabolism in the intestinal ends next to the resection site. This hypermetabolism neither deteriorated nor turned into ischemia during the initial postoperative course, but the start of hypoxemia could not be excluded during the study and after the placement of an FCSEMS.

Altered mRNA Expression Due to Rectal Perforation in a Porcine Model - A Pilot Study.

BACKGROUND: Anastomotic leakage is the most serious and unwelcome complication in rectal surgery. It has a great impact on postoperative morbidity and mortality. In this pilot study, changes of mRNA expression in blood were analyzed in an animal model designed to imitate anastomotic leakage. MATERIALS AND METHODS: Twelve pigs were randomized into two groups: A sham-operated control group and an experimental group in which iatrogenic rectal perforation was performed. The changes in the mRNA expression at 4 hours after creating the perforation were studied. Microarray analysis was performed using Gene Chip whole porcine genome array. mRNA expression of 19,124 genes was investigated. RESULTS: Significantly increased levels of genes with a fold change greater than 2 were found, including 276 coding for unknown proteins and 48 coding for known proteins. Eleven of those which coded for known proteins were up-regulated with a fold change >4. CONCLUSION: Eleven known genes were highly up-regulated after rectal perforation. These genes were mainly involved in inflammatory response, intracellular signaling and cell membrane regulation. Their corresponding proteins might potentially be clinical biomarkers of anastomotic leakage and should be evaluated in further clinical studies.

Swimming-Induced Pulmonary Edema: Evaluation of Prehospital Treatment With CPAP or Positive Expiratory Pressure Device.

BACKGROUND: Swimming-induced pulmonary edema (SIPE) occasionally occurs during swimming in cold open water. Although optimal treatment for SIPE is unknown, non-invasive positive pressure ventilation (NPPV) is an option for prehospital treatment. RESEARCH QUESTION: Is NPPV a feasible and safe prehospital treatment for SIPE, and which outcome measures reflect recovery after treatment? STUDY DESIGN AND METHODS: A prospective observational study was conducted at Vansbrosimningen, Sweden's largest open water swimming event, from 2017 through 2019. Swimmers with a diagnosis of SIPE and with peripheral oxygen saturation (Spo2) of ≤ 95%, persistent respiratory symptoms, or both were eligible for the study. NPPV was administered on site as CPAP by facial mask or as positive expiratory pressure (PEP) by a PEP device. Discharge criteria were Spo2 of > 95% and clinical recovery. Four outcome measures were evaluated: Spo2, crackles on pulmonary auscultation, pulmonary edema on lung ultrasound (LUS), and patient-reported respiratory symptoms. RESULTS: Of 119 treated individuals, 94 received CPAP, 24 received treatment with a PEP device, and one required tracheal intubation. In total, 108 individuals (91%) were discharged after NPPV for a median of 10 to 20 min and 11 individuals (9%) required hospital transfer. NPPV resulted in increased Spo2 from a median of 91% to 97% (P < .0001) together with improvement of six patient-reported respiratory symptoms (median numerical rating scales, 1-7 to 0-1; P < .0001). No significant decrease in auscultation of crackles (93% vs 87%; P = .508) or pulmonary edema on LUS (100% vs 97%; P = .500) was seen during NPPV treatment. INTERPRETATION: NPPV administered as CPAP or via a PEP device proved feasible and safe as prehospital treatment for SIPE with a vast majority of patients discharged on site. Spo2 and patient-reported respiratory symptoms reflected recovery after treatment, whereas pulmonary auscultation or LUS findings did not.

Low profile REBOA device for increasing systolic blood pressure in hemodynamic instability: single-center 4-year experience of use of ER-REBOA.

BACKGROUND: Hemodynamic instability due to torso hemorrhage can be managed with the assistance of resuscitative endovascular balloon occlusion of the aorta (REBOA). This is a report of a single-center experience using the ER-REBOA™ catheter for traumatic and non-traumatic cases as an adjunct to hemorrhage control and as part of the EndoVascular resuscitation and Trauma Management (EVTM) concept. The objective of this report is to describe the clinical usage, technical success, results, complications and outcomes of the ER-REBOA™ catheter at Örebro University hospital, a middle-sized university hospital in Europe. METHODS: Data concerning patients receiving the ER-REBOA™ catheter for any type of hemorrhagic shock and hemodynamic instability at Örebro University hospital in Sweden were collected prospectively from October 2015 to May 2020. RESULTS: A total of 24 patients received the ER-REBOA™ catheter (with the intention to use) for traumatic and non-traumatic hemodynamic control; it was used in 22 patients. REBOA was performed or supervised by vascular surgeons using 7-8 Fr sheaths with an anatomic landmark or ultrasound guidance. Systolic blood pressure (SBP) increased significantly from 50 mmHg (0-63) to 95 mmHg (70-121) post REBOA. In this cohort, distal embolization and balloon rupture due to atherosclerosis were reported in one patient and two patients developed renal failure. There were no cases of balloon migration. Overall 30-day survival was 59%, with 45% for trauma patients and 73% for non-traumatic patients. Responders to REBOA had a significantly lower rate of mortality at both 24 h and 30 days. CONCLUSIONS: Our clinical data and experience show that the ER-REBOA™ catheter can be used for control of hemodynamic instability and to significantly increase SBP in both traumatic and non-traumatic cases, with relatively few complications. Responders to REBOA have a significantly lower rate of mortality.

Hemodynamic Effect of Resuscitative Endovascular Balloon Occlusion of the Aorta in Hemodynamic Instability Secondary to Acute Cardiac Tamponade in a Porcine Model.

BACKGROUND: The pre-hospital use of Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) is increasing, although it remains controversial, in part because of suggested contraindications such as acute cardiac tamponade (ACT). As both the pre-hospital and in-hospital use of REBOA might potentially occur with concurrent ACT, knowledge of the hemodynamic effect of REBOA in this setting is crucial. This study, therefore, aimed at investigating the physiological effects of REBOA in hemodynamic instability secondary to ACT in a porcine model. We hypothesize that REBOA can temporarily increase systemic blood pressure and carotid blood flow, and prolong survival, in hemodynamic shock caused by ACT. METHODS: Fourteen pigs (24-38 kg) underwent ACT, through true cardiac injury and hemorrhage into the pericardial space, and were allowed to hemodynamically deteriorate. At a systolic blood pressure (SBP) of 50 mm Hg (SBP50) they were randomized to total occlusion REBOA in zone 1 or to a control group. Survival, hemodynamic parameters, carotid blood flow (CBF), femoral blood flow (FBF), cardiac output (CO), end-tidal CO2, and arterial blood gas parameters were analyzed. RESULTS: REBOA intervention was associated with a significant increase in SBP (50 mm Hg to 74 mm Hg, P = 0.016) and CBF (110 mL/min to 195 mL/min, P = 0.031), with no change in CO, compared to the control group. At 20 min after SBP50, the survival rate in the intervention group was 86% and in the control group 14%, with time to death being significantly longer in the intervention group. CONCLUSIONS: This randomized animal study demonstrates that REBOA can help provide hemodynamic stabilization and prolong survival in hemodynamic shock provoked by ACT. It is important to stress that our study does not change the fact that urgent pericardiocentesis or cardiac surgery is, and should remain, the standard optimal treatment for ACT.Level of evidence: Prospective, randomized, experimental animal study. Basic science study, therapeutic.

A Single Center Study of ProGlide Used for Closure of Large-Bore Puncture Holes After EVAR for AAA.

PURPOSE: The objective of this study was to evaluate the primary and assisted secondary percutaneous and non-invasive technical success of the ProGlide device on all-comers in a consecutive case series of percutaneous endovascular aortic aneurysm repair (P-EVAR). METHOD: A single-center consecutive case series where 434 elective and acute P-EVAR procedures were registered prospectively between May 2011 and July 2017. The mean age was 74.5 years ± SD 11.4 years. 82.3% of the patients were male. All patients were pre-planned from CT angiography. Percutaneous access punctures, performed in local anesthesia in the common femoral artery, with a final introducer size between 12-22 Fr OD were included and stratified in 2 groups, 12-16 Fr and 17-22 Fr. RESULTS: By screening 868 access groins 22 groins were excluded. Of the remaining 846 groins, intended to be treated with ProGlide, 9 groins were excluded peri-procedurally and treated with the Fascia Suture Technique or surgical cutdown. The remaining 837 groins had access closure with ProGlide, with a mean value of 2.15 devices per groin with a slight significant difference between the 2 stratification groups. Primary ProGlide technical success was achieved in 68.1% of the groins. Secondary percutaneous or non-invasive technical success was achieved in 96.9%. Here there was no statistically significant difference between the 2 stratification groups. Thirty-one (3.7%) groin complications were registered during 30-day follow-up and 17 required additional treatment. Total mortality was 2.8%. None of these deaths were related to the access site. CONCLUSION: ProGlide by itself has a significant failure rate in the closure of large-bore access holes on an unselected cohort of patients eligible for P-EVAR. However, together with adjunct percutaneous or non-invasive methods a success rate of 97% can be achieved. The access complication rate was lower than 4% at 30-day follow-up.

Novel Experimental Technique to Create Size-Controlled Retroperitoneal Bleeding in the Infrarenal Aorta of Anesthetized Pigs.

OBJECTIVE: Rupture of abdominal aortic aneurysm (rAAA) with a contained retroperitoneal hematoma is potentially fatal. Physiological studies are difficult to perform in patients suffering from life-threatening conditions such as rAAA. A translational model of the condition is therefore needed. The aim was to develop and validate an endovascular animal model for retroperitoneal bleeding of the abdominal aorta with contained hematoma. METHODS: In anesthetized pigs, a puncture hole was made in the posterolateral portion of the infrarenal aorta by an Outback re-entry catheter device. The hole was gradually enlarged using angioplasty balloons to a specific diameter of either 4 mm (n = 6), 6 mm (n = 7), or 8 mm (n = 6). Onset of bleeding was verified by angiography and macroscopically examined on completion of the experiments. Survival up to 180 min was the primary outcome. Hemodynamic and metabolic markers in arterial blood were secondary outcomes. RESULTS: Aortic injury with a contained retroperitoneal hematoma was achieved in all animals. Survival rate at 180 min after onset of bleeding was higher in the 4 mm group compared to the 6 mm (P = 0.021) and 8 mm groups (P = 0.002), but not when comparing the 6 mm and 8 mm groups. Systemic hypotension, arterial acidosis, and lactatemia were provoked in the 6 mm and 8 mm groups but not in the 4 mm group. CONCLUSIONS: A porcine model for a controlled contained left posterolateral retroperitoneal bleeding was created using endovascular methods and validated. This model makes it possible to study the pathophysiology of a retroperitoneal hematoma.

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

INTRODUCTION: 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. MATERIALS AND METHODS: 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. RESULTS: 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). CONCLUSION: 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.

Intestinal fatty acid-binding protein and acute gastrointestinal injury grade in postoperative cardiac surgery patients.

BACKGROUND AND AIM: Gastrointestinal complications post cardiac surgery are infrequent but difficult to diagnose and carry a high mortality. Plasma intestinal fatty acid-binding protein (I-FABP) concentrations and the relationship between I-FABP, gastrointestinal dysfunction, and postoperative outcomes were investigated in patients who developed gastrointestinal dysfunction (acute gastrointestinal injury [AGI] grade ≥2) and those with normal gastrointestinal function. METHODS: Patients with (AGI 2 group, n = 11) and without (matched controls, AGI 0 group, n = 22) early postoperative gastrointestinal dysfunction were extracted from a larger single-center prospective observational study, including adults undergoing elective cardiac surgery with extracorporeal circulation, and investigated in this nested case-control analysis. RESULTS: Both groups displayed variations in I-FABP concentrations with higher I-FABP on postoperative Day 1 compared to baseline and postoperative Days 2 and 3 (p < .001 and p = .005, respectively). The AGI 2 group had higher I-FABP concentrations on Day 2 compared to the AGI 0 group (p = .024). I-FABP on Day 2 correlated positively with AGI grade over the first 3 days (p = .036, p = .021 and p = .018, respectively). High I-FABP (defined as fourth quartile concentrations) on Day 1 was associated with more prolonged surgical procedures (p < .05). Furthermore, fourth quartile I-FABP on Day 1 and early gastrointestinal dysfunction were associated with higher frequencies of postoperative organ dysfunction (p < .05) and gastrointestinal complications (p < .05), and higher 365-day mortality. CONCLUSION: The present study indicates an association between intraoperative gastrointestinal injury, postoperative gastrointestinal dysfunction and gastrointestinal complications. A high-powered study is needed to further explore this relationship and the interpretation of I-FABP concentrations in individual cardiac surgery patients.

A randomized porcine study of the hemodynamic and metabolic effects of combined endovascular occlusion of the vena cava and the aorta in normovolemia and in hemorrhagic shock.

BACKGROUND: Mortality from traumatic retrohepatic venous injuries is high and methods for temporary circulatory stabilization are needed. We investigated survival and hemodynamic and metabolic effects of resuscitative endovascular balloon occlusion of the aorta (REBOA) and vena cava inferior (REBOVC) in anesthetized pigs. METHODS: Twenty-five anesthetized pigs in normovolemia or severe hemorrhagic shock (controlled arterial bleeding in blood bags targeting systolic arterial pressure of 50 mm Hg, corresponding to 40-50% of the blood volume) were randomized to REBOA zone 1 or REBOA+REBOVC zone 1 (n = 6-7/group) for 45 minutes occlusion, followed by 3-hour resuscitation and reperfusion. Hemodynamic and metabolic variables and markers of end-organ damage were measured regularly. RESULTS: During occlusion, both the REBOA groups had higher systemic mean arterial pressure (MAP) and cardiac output (p < 0.05) compared with the two REBOA+REBOVC groups. After 60 minutes reperfusion, there were no statistically significant differences between the two REBOA groups and the two REBOA+REBOVC groups in MAP and cardiac output. The two REBOA+REBOVC groups had higher arterial lactate and potassium concentrations during reperfusion, compared with the two REBOA groups (p < 0.05). There was no major difference in end-organ damage markers between REBOA and REBOA+REBOVC. Survival after 1-hour reperfusion was 86% and 100%, respectively, in the normovolemic REBOA and REBOA+REBOVC groups, and 67% and 83%, respectively, in the corresponding hemorrhagic shock REBOA and REBOA+REBOVC groups. CONCLUSION: Acceptable hemodynamic stability during occlusion and short-term survival can be achieved by REBOA+REBOVC with adequate resuscitation; however, the more severe hemodynamic and metabolic impacts of REBOA+REBOVC compared with REBOA must be considered. LEVEL OF EVIDENCE: Prospective, randomized, experimental animal study. Basic science study, therapeutic.