To Örebro University

BACKGROUND: Resuscitative endovascular balloon occlusion of the aorta (REBOA) causes physiological, metabolic, end-organ and inflammatory changes that need to be addressed for better management of severely injured patients. The aim of this study was to investigate occlusion time-dependent metabolic, end-organ and inflammatory effects of total REBOA in Zone I in a normovolemic animal model.

METHODS: Twenty-four pigs (25-35 kg) were randomized to total occlusion REBOA in Zone I for either 15, 30, 60 min (REBOA15, REBOA30, and REBOA60, respectively) or to a control group, followed by 3-h reperfusion. Hemodynamic variables, metabolic and inflammatory response, intraperitoneal and intrahepatic microdialysis, and plasma markers of end-organ injuries were measured during intervention and reperfusion. Intestinal histopathology was performed.

RESULTS: Mean arterial pressure and cardiac output increased significantly in all REBOA groups during occlusion and blood flow in the superior mesenteric artery and urinary production subsided during intervention. Metabolic acidosis with increased intraperitoneal and intrahepatic concentrations of lactate and glycerol was most pronounced in REBOA30 and REBOA60 during reperfusion and did not normalize at the end of reperfusion in REBOA60. Inflammatory response showed a significant and persistent increase of pro- and anti-inflammatory cytokines during reperfusion in REBOA30 and was most pronounced in REBOA60. Plasma concentrations of liver, kidney, pancreatic and skeletal muscle enzymes were significantly increased at the end of reperfusion in REBOA30 and REBOA60. Significant intestinal mucosal damage was present in REBOA30 and REBOA60.

CONCLUSION: Total REBOA caused severe systemic and intra-abdominal metabolic disturbances, organ damage and inflammatory activation already at 30 min of occlusion.

INTRODUCTION: Aortic occlusion during cardiopulmonary resuscitation (CPR) increases systemic arterial pressures. Correct thoracic placement during the resuscitative endovascular balloon occlusion of the aorta (REBOA) may be important for achieving effective CPR.

HYPOTHESIS: The positioning of the REBOA in the thoracic aorta during CPR will affect systemic arterial pressures.

METHODS: Cardiac arrest was induced in 27 anesthetized pigs. After 7 min of CPR with a mechanical compression device, REBOA in the thoracic descending aorta at heart level (zone Ib, REBOA-Ib, n = 9), at diaphragmatic level (zone Ic, REBOA-Ic, n = 9) or no occlusion (control, n = 9) was initiated. The primary outcome was systemic arterial pressures during CPR.

RESULTS: During CPR, REBOA-Ic increased systolic blood pressure from 86 mmHg (confidence interval [CI] 71-101) to 128 mmHg (CI 107-150, P < 0.001). Simultaneously, mean and diastolic blood pressures increased significantly in REBOA-Ic (P < 0.001 and P = 0.006, respectively), and were higher than in REBOA-Ib (P = 0.04 and P = 0.02, respectively) and control (P = 0.005 and P = 0.003, respectively). REBOA-Ib did not significantly affect systemic blood pressures. Arterial pH decreased more in control than in REBOA-Ib and REBOA-Ic after occlusion (P = 0.004 and P = 0.005, respectively). Arterial lactate concentrations were lower in REBOA-Ic compared with control and REBOA-Ib (P = 0.04 and P < 0.001, respectively).

CONCLUSIONS: Thoracic aortic occlusion in zone Ic during CPR may be more effective in increasing systemic arterial pressures than occlusion in zone Ib. REBOA during CPR was found to be associated with a more favorable acid-base status of circulating blood. If REBOA is used as an adjunct in CPR, it may be of importance to carefully determine the aortic occlusion level.The study was performed following approval of the Regional Animal Ethics Committee in Linköping, Sweden (application ID 418).

INTRODUCTION: Resuscitative endovascular balloon occlusion of the aorta (REBOA) in zone I increases systemic blood pressure during cardiopulmonary resuscitation (CPR), while also obstructing the blood flow to distal organs. The aim of the study was to compare the effects on systemic blood pressure and visceral blood flow of REBOA-III (zone III, infrarenal) and REBOA-I (zone I, supraceliac) during non-traumatic cardiac arrest and CPR.

METHODS: Cardiac arrest was induced in 61 anesthetized pigs. Thirty-two pigs were allocated to a hemodynamic study group where the primary outcomes were systemic arterial pressures and 29 pigs were allocated to a blood flow study group where the primary outcomes were superior mesenteric arterial (SMA) and internal carotid arterial (ICA) blood flow. After 7-8minutes of CPR with a mechanical compression device, REBOA-I, REBOA-III or no aortic occlusion (control group) were initiated after randomization.

RESULTS: Systemic mean and diastolic arterial pressures were statistically higher during CPR with REBOA-I compared to REBOA-III (50mmHg and 16mmHg in REBOA-I vs 38mmHg and 1mmHg in REBOA-III). Systemic systolic, mean and diastolic arterial pressures were statistically elevated during CPR in the REBOA-I group compared to the controls. The SMA blood flow increased by 49% in REBOA-III but dropped to the levels of the controls within minutes. The ICA blood flow increased the most in REBOA-I compared to REBOA-III and the control group (54%, 19% and 0%, respectively).

CONCLUSION: In experimental non-traumatic cardiac arrest and CPR, REBOA-I increased systemic blood pressures more than REBOA-III, and the potential enhancement of visceral organ blood flow by REBOA-III was short-lived.