Exploring aortic morphology and determining variable-distance insertion lengths for fluoroscopy-free resuscitative endovascular balloon occlusion of the aorta (REBOA)

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is used to temporary control non-compressible truncal hemorrhage (NCTH) as bridge to definitive surgical treatment. The dependence on radiography for safe balloon positioning is one factor that limits the extended use of REBOA in civilian and military pre-hospital settings. We aimed to determine standardized sex and age-based variable-distance catheter insertion lengths for accurate REBOA placement without initial fluoroscopic confirmation. Contrast enhanced CT-scans from a representative sample of a Dutch non-trauma population were retrospectively analyzed. Intravascular distances were measured from the bilateral common femoral artery access points (FAAP) to the middle of the aortic occlusion zones and accompanying boundaries. Means and 95% confidence intervals for the distances from the FAAPs to the boundaries and mid-zone III were calculated for all (combined) sex and age-based subgroups. Optimal insertion lengths and potentially safe regions were determined for these groups. Bootstrap analysis was performed in combination with a 40-mm long balloon introduction simulation to determine error-rates and REBOA placement accuracy for the general population. In total, 1354 non-trauma patients (694 females) were included. Vascular distances increased with age and were longer in males. The iliofemoral trajectory was 7 mm longer on the right side. The optimal zone I catheter insertion length would be 430 mm. Optimal zone III catheter insertion lengths showed up to 30 mm difference, ranging between 234 and 264 mm. Statistically significant and potentially clinically relevant differences were observed between the anatomical distances and necessary introduction depths for each subgroup. This is the first study to compare aortic morphology and intravascular distances between combined sex and age-based subgroups. As zone III length was consistent, length variability and elongation seem to mainly originate in the iliofemoral trajectory and zone II. The optimal zone I catheter insertion length would be 430 mm. Optimal zone III catheter insertion ranged between 234 and 264 mm. These standardized variable-distance insertion lengths could facilitate safer fluoroscopy-free REBOA in austere, pre-hospital settings.