Morphometric and Physiologic Modeling Study for Endovascular Occlusion in Pediatric Trauma Patients

Abstract

Background- The use of the Resuscitative Endovascular Balloon Occlusion (REBOA) device is expanding in adult trauma. Reports of its use in pediatric patients have been published but no guidelines are established nor has it been FDA approved in pediatric use. Methods- 289 CT scans were reviewed to determine the average aortic diameter at the xyphoid process and umbilicus for each Broselow category. These measurements were the basis of 3D printed aortas using TangoPlus FullCure 930®. These aortas were inserted into a circulatory system model featuring two tracks to simulate thoracic and cerebral perfusion. Sonographic flow meters and pressure monitors were placed throughout and flow and pressure readings were recorded as a REBOA device was inflated in the printed aorta segment. Results- Distal aortic flow and pressure decreased while the cerebral branch demonstrated an inverse increase in flow and pressure with REBOA inflation. An initial delay between inflation and flow occlusion was noted with the initial 50% of volume inflated causing a 10% reduction in flow. The REBOA balloon inflation volumes (cc) for each Broselow Category for zone 1 and 3 are as follows: Black 7.5 & 5.5, Green 6 & 3.5, Orange 5.5 & 3, Blue 5 & 2, White 3 & 1.5 Conclusions- Pediatric patients present with a range of vessel sizes that occlude with a range of REBOA balloon inflation volumes. This study provides a basis to establish initial inflation volumes for REBOA deployment in appropriate pediatric trauma patients.

Balloons for kids: Anatomic candidacy and optimal catheter size for pediatric resuscitative endovascular balloon occlusion of the aorta

“…Vessel diameters were also found to have greatest correlation with patient height in pediatric patients. Previous studies have documented similar findings and have also found a strong correlation between body surface area and vessel diameter 15,16,20 . These data support the use of the Broselow tape categorization for determination of REBOA catheter size in children.…”

“…Previous studies have documented similar findings and have also found a strong correlation between body surface area and vessel diameter. 15,16,20 These data support the use of the Broselow tape categorization for determination of REBOA catheter size in children. A recent model-based study testing the balloon occlusion capability of commercially available balloon catheters deliverable through 4-Fr, 5-Fr, and 6-Fr sheaths found that these catheters were able to successfully occlude pediatric-sized aortic test lumens in the setting of physiologic pulsatile flow.…”

Successful Damage Control Resuscitation with Resuscitative Endovascular Balloon Occlusion of the Aorta in a Pediatric Patient

“…3A). Carrillo et al [7] showed the appropriate REBOA balloon inflation volumes for each Broselow category for Zones 1 and 3. Based on this study, to block aortic flow by 50%, the optimal inflation volume in Zone 1 for a child who is 130 cm tall is 5.5 mL.…”

循環動態不安定な小児外傷性肝損傷に対し防災ヘリ搬送のため約1時間のIABO inflationを行った1救命例(Survival of a hemodynamically unstable pediatric patient with liver trauma who underwent 1h aortic balloon occlusion for air transport)

“…体格面で制約を受ける小児患者に適切なバルーン容量でIABOを使用するために，近年ではCT画像を基に体格ごとの大動脈径を推定する試みが行われている 8)。しかし，血管径の小さな小児患者では既存のIABOが容易に過膨張となり，わずかなバルーン容量変化が血流に大きく影響するため遮断管理が極めて困難となる可能性が指摘されている 9), 10)。バルーン遮断の際には中枢臓器還流の指標として遮断近位側の血圧モニタリングが必要であるが，同時に遮断遠位側の血圧モニタリングを行うことによって血流遮断の程度を評価することができる。それによって，適切なバルーン量調節が容易となり，小児でもバルーン過膨張や意図しない血流遮断を回避した管理が可能となる。本症例では，前医から約60km離れた当院への搬送までに状態悪化の懸念があったため，IABOを使用しながら搬送を行うことで救命へとつなげることができた。しかし，前医ではIABO留置後すぐにバルーン遮断が開始されているが，それまでの血圧経過では収縮期血圧が約100mmHg以上で推移しており，外傷診療におけるpermissive hypotensionの考えからはこの時点でのバルーン遮断は必ずしも必要ではなかった可能性が考えられる。その後も，バルーン容量が20mLから15mLへと変更されているが，小児の体格を考慮すると変更後もover inflationとなっていた可能性は否定できない。搬送までの経過中に遮断遠位部の脈拍確認は行われておらず，over inflationによる血管損傷を回避するためにもIABO対側の大腿動脈拍動を確認しながら，収縮期血圧が90mmHg前後となるようにバルーン調節を行う必要があった。IABO導入時はエコー下穿刺を行うことで，血管径の小さな小児患者でも迅速なシース留置が可能であった。また，バルーン拡張前には透視での位置確認によって小児の体格に合わせた留置が容易であった。…”