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- Dogan, Emanuel M., 1984-
(author)
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Endovascular occlusion methods in non-traumatic cardiac arrest
- 2021
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Doctoral thesis (other academic/artistic)abstract
- Approximately 10% of out-of-hospital cardiac arrest patients survive to hospital discharge. An important factor for survival is perfusion to the coronary and cerebral circulations during cardiopulmonary resuscitation (CPR). Resuscitative endovascular balloon occlusion of the aorta (REBOA) is an endovascular method used to centralize the circulation and augment blood flow to the heart and brain. REBOA is mostly used in trauma patients but its use in non-traumatic cardiac arrest (NTCA) is evolving. The effects and optimal location of REBOA during CPR are, however, not well-known. Intra-aortic balloon pump (IABP) is another endovascular method which, unlike REBOA, inflates and deflates in correlation with the heart’s contraction and relaxation cycles. IABP is mostly used in patients with cardiogenic shock and its usage has been sparsely studied in NTCA. In addition, there are no studies evaluating if an intra-caval balloon pump (ICBP) could increase venous return during CPR. The aim of this thesis was to investigate endovascular occlusion methods in NTCA and how they influence the hemodynamic parameters during CPR. All studies were experimental where a total of 133 pigs were included.In Study I, REBOA increased systemic blood pressures while causing an ischemic insult to organs distal to the occlusion, already at 30 min of occlusion.Study II showed that a REBOA placed below the heart and outside of the compression field increased arterial blood pressures more than if the REBOA was placed behind the heart during NTCA and CPR.Study III compared REBOA in zone I (thoracic) with REBOA in zone III (infrarenal) during experimental CPR. Zone III REBOA did not yield the same favorable circulatory response as zone I REBOA.Study IV showed that IABP increased hemodynamic values if it was inflated before the chest compression. An ICBP did not improve hemodynamic values.Conclusion: REBOA caused a time-dependent ischemic insult, a maximum total occlusion time of 15-30 min is suggested. When an optimally placed REBOA and an optimally synchronized IABP are used in NTCA and CPR, they improve hemodynamic variables.
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| 2. |
- Oikonomakis, Ioannis, 1977-
(author)
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Anastomotic leakage in colorectal surgery : early diagnosis and treatment with stent
- 2021
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Doctoral thesis (other academic/artistic)abstract
- Every year inn Sweden more than 6000 individuals are diagnosed with colorectal cancer and more than 5000 operations are performed. Anastomotic leakage (AL) is the most dreaded complication in colorectal surgery and has a great impact on postoperative morbidity and mortality. In Study I, an iatrogenic rectal perforation was performed on an experimental group of pigs, in order to imitate AL and compared with a control group which had a sham operation over a 10-hours follow-up with intraperitoneal microdialysis (IPM) and cytokines. Glucose levels were lower in the experimental group at 4 hours and lactate and lactate/pyruvate ratios (L/P) were higher in the experimental group at 7 hours. Intraperitoneal (IP) Interleukine 6 (IL6) and Interleukine 10 (IL10) were higher in the experimental group at 10 hours and blood IL6 was higher in the experimental group at 4 hours. IPM and cytokines thus seem to react early after rectal perforation. Study II was a prospective observational study in which 7 patients with AL after surgery were compared with 13 patients without complications during the first 7 postoperative days with IPM, and intravenous and IP cytokines. In patients who later developed AL, IP lactate and L/P were higher immediately after surgery, while glycerol levels were lower. At the anastomosis higher L/P in AL patients were found after the fifth postoperative day. Intravenous and IP IL6 was higher in the leakage group. In Study III, mRNA expression in blood was analyzed in an animal model designed to imitate AL. Significantly increased levels of 276 genes were found and 11 of the 48 genes which coded for a known protein were highly up-regulated.In Study IV, the metabolic effects of a fully covered self-expandable metal stent (FCSEMS) over a colorectal anastomosis were investigated with IPM, after laparotomy, colon resection and anastomosis with stent. Lactate and L/P rise at the oral part of the anastomosis were significantly higher, while glucose showed a small tendency toward numerically declining values. At the distal part of the anastomosis glucose decreased significantly after the resection but did not reach zero. Lactate increased significantly while L/P slightly increased. This suggest that hypermetabolism occurs in the intestinal ends next to the resectate, but even a start of hypoxemia cannot be excluded after the placement of a FCSEMS.
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| 3. |
- Wikström, Maria B., 1972-
(author)
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Resuscitative Endovascular Balloon Occlusion of the Inferior Vena Cava (REBOVC) : Experimental and clinical studies
- 2024
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Doctoral thesis (other academic/artistic)abstract
- Juxtahepatic venous injuries often cause life-threatening hemorrhagic shock, the mortality is high and new management methods are needed. The aims were to explore endovascular methods for retrohepatic vascu-lar isolation, their effects on survival, hemodynamics, metabolism, end-organ damage and bleeding, and if ultrasound and anatomical land-marks could be used to guide placement of resuscitative endovascular balloon occlusion of the inferior vena cava (REBOVC). Study I ex-plored the effects of different combinations of REBOVC +/- endovascu-lar aortic balloon occlusion (REBOA) +/- the Pringle maneuver (PM) for 5 minutes in anesthetized pigs (n=9). REBOVC was found to be tol-erated hemodynamically if combined with REBOA whereas REBOVC alone or combined with PM was not. In study II, REBOA was com-pared to REBOA + REBOVC in normovolemia and in hemorrhagic shock in anesthetized pigs (n=6-7/group). REBOA + REBOVC was tol-erated for 45 minutes, but negative hemodynamic and metabolic ef-fects in hemorrhagic shock must be considered. In Study III, the effects in anesthetized pigs of different combinations of balloon occlusion (REBOA vs REBOA + REBOVC vs REBOA + infra- and suprahepatic REBOVC + portal vein occlusion) on survival, hemodynamics, retrohe-patic bleeding, metabolism, and collateral flow were compared to no occlusion. REBOA was found to most efficiently stabilize hemodynam-ics and prolong survival despite larger collateral flow and retrohepatic bleeding. The inability of venous occlusion to stabilize hemodynamics as efficiently as REBOA was probably due to a combination of arterial collateral flow combined with reduced venous return. Studies IV + V examined if ultrasound (in anesthetized pigs, n=9) and anatomical landmarks (computerized tomography images from 50 humans) could be used to position REBOVC and found that subxiphoidal ultrasound and external landmarks can be useful tools to adequately position RE-BOVC in the inferior vena cava.
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| 4. |
- Sadeghi, Mitra, 1982-
(author)
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Resuscitative endovascular balloon occlusion of the aorta : Physiology and clinical aspects of an emerging technique
- 2019
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Doctoral thesis (other academic/artistic)abstract
- Traumatic hemorrhagic shock is a major cause of death worldwide. Patients enter the fatal triad of hypothermia, acidosis and coagulopathy and die quickly due to cardiovascular collapse. Ideally, procedures should be performed at the injury scene to prevent this fatal event. Unfortunately, intervention cannot be performed as soon as is needed and time to intervention becomes the enemy of survival. Hemorrhage control until definitive repair can possibly save lives. Hemorrhage from the extremities can be controlled by external pressure but severe hemorrhage from thoracic, abdominal or pelvic cavities, called non-compressible torso hemorrhage, requires internal hemorrhage control. Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) uses an endovascular balloon that is inserted into the aorta using minimally invasive methods and is inflated to increase perfusion pressure and avoid cardiovascular collapse, providing a bridge to intervention. REBOA is hypothetised to increase central blood pressure but cause ischemia reperfusion injury below the occlusion level. The purpose of this thesis was to investigate the general impact of REBOA on physiology, metabolism, inflammatory response in normovolemia and hemorrhage. Investigation was conducted through clinical and experimental models.Study I was a multicentre cohort study of patients with traumatic hemorrhagic shock who received REBOA. Ninety-six patients were included, with an overall mortality of 56% and with no major complications from REBOA use. REBOA was used in a continuous and non-continuous fashion depending on the patients’ level of hypovolemia.Study II and the following three studies were animal experimental studies. Study II was a randomized control study in pigs to evaluate physiological, metabolic, inflammatory and end-organ function in a normovolemic state. It was demonstrated that REBOA increased central blood pressure but caused ischemic insult.Study III, a randomised controlled experimental model in pigs. Investigation was made to examine the possibility of titrating blood pressure with partial occlusion and investigate if partial occlusion reduced the ischemic insult. Partial REBOA could be achieved in this study and the ischemia reperfusion injury was less pronounced in partial occlusion than total. However, the difficulty regarding how to determine partial occlusion in a clinical setting remained.Study IV was therefore an experimental study conducted to compare the different methods of determining partial occlusion and detect the best correlation to organ perfusion. The following variables were compared to oxygen consumption: end-tidal carbon dioxide, aortic blood flow, superior mesenteric blood flow and femoral mean pressure. The study revealed that end-tidal carbon dioxide correlates best to organ perfusion.
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