To Örebro University

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.