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

Abstract

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.

Figure 1

The experimental flow chart of the study (panel A) showing the two interventions investigated, the combination of REBOA and REBOVC or REBOA in the two study conditions (normovolemia and hemorrhagic shock). The anatomical placement of REBOA and REBOVC via catheterization in the right femoral artery and vein, respectively, and the withdrawal of blood into a citrate-containing bag via an introducer in the left femoral vein (panel B). The survival of the animals randomized to each group (panel C).

Figure 2

Systemic mean arterial blood pressure (MAP, panel A), CO (panel B), CVP (panel C) and mean MVP (panel D) in anesthetized pigs subjected to either REBOA or a combination of REBOA and REBOVC for 45 minutes in normovolemia and hemorrhagic shock (H) followed by 3 hours of reperfusion and resuscitation. Number of animals in each group at start of reperfusion: Normovolemia + REBOA (n = 7), Normovolemia + REBOA+REBOVC (n = 6), Hemorrhagic shock + REBOA (n = 6) and Hemorrhagic shock + REBOA+REBOVC (n = 6). (A), Statistically significant difference during normovolemia between REBOA and REBOA+REBOVC, (B) Statistically significant difference during hemorrhagic shock between REBOA and REBOA+REBOVC, (C) Statistically significant difference between normovolemia and hemorrhagic shock with REBOA, (D) Statistically significant difference between normovolemia and hemorrhagic shock with REBOA +REBOVC. (B) and (D), significances are not analyzed at the last time point due to low number of surviving animals in hemorrhagic REBOA+REBOVC. Data are means and 95% confidence intervals.

Figure 3

Systemic arterial pH (A) lactate concentration (B) and potassium concentration (K+, C) in anesthetized pigs subjected to either REBOA or a combination of REBOA and REBOVC for 45 minutes in normovolemia and hemorrhagic shock (H) followed by 3 hours of reperfusion and resuscitation. Number of animals in each group at start of reperfusion: Normovolemia + REBOA (n = 7), Normovolemia + REBOA+REBOVC (n = 6), Hemorrhagic shock + REBOA (n = 6) and Hemorrhagic shock + REBOA+REBOVC (n = 6). (A), Statistically significant difference during normovolemia between REBOA and REBOA+REBOVC, (B) Statistically significant difference during hemorrhagic shock between REBOA and REBOA+REBOVC, (C) Statistically significant difference between normovolemia and hemorrhagic shock with REBOA, (D) Statistically significant difference between normovolemia and hemorrhagic shock with REBOA +REBOVC. (B) and (D), significances are not analyzed at the last time point due to low number of surviving animals in hemorrhagic REBOA+REBOVC. Data are means and 95% confidence intervals.