Highlights from #EAST2015 - Is expanding foam the answer to intraabdominal hemorrhage?

More work from Dr. King's group on expandable foam for hemorrhage.

Moving from swine to humans...

SELF-EXPANDING FOAM FOR SEVERE ABDOMINAL HEMORRHAGE: A MULTI-CENTER DOSE TRANSLATION STUDY IN RECENTLY DECEASED HUMANS

David King, MD*, Adam P. Rago, MS, Tomaz Mesar, Mackenzie R. Cook, Andreas Larentzakis, Jeanette M. Podbielski, RN BSN, Ryan A. Lawless, MD*, Samantha Underwood, MS, Martin A. Schreiber, MD, FACS*,
John B. Holcomb, MD*, Upma Sharma, PhD
Massachusetts General Hospital

Objectives: Severe noncompressible abdominal bleeding results in 50% mortality in both military and civilian populations. There is an emergent need for a temporary intervention whenever surgical care is not immediately available. We previously described a self-expanding polyurethane foam for treatment of exsanguinating abdominal hemorrhage. The objective of this study was to translate a safe and effective swine dose into an appropriate human dose through foam administration in recently deceased humans with representative tissue compliance.

Methods: With IRB oversight and informed consent at three centers, patients imminently expected to die were identified. Within 3 hours of death, the abdomen was accessed and fluid was added to simulate hemorrhage. Foam was administered using a prototype delivery system. A foam dose of 45 mL was selected based on biostatistical models comparing swine and humans. Intraabdominal pressure (IAP) was monitored for 15 minutes, then foam was removed to assess abdominal tissue contact (0=no contact, 1=some contact, 2=full contact).

Results: N=5 subjects, ranging in age (29-87 yr) and body habitus (BMI 24-35 kg/m2), were enrolled at the 45 mL dose. ΔIAP and semi-quantitative organ contact were used as surrogates to compare findings between humans and swine. 45mL foam resulted in a peak pressure of 27±7.7 mmHg, within the acceptable range defined by swine studies. Organ contact was variable, but less than that observed in swine at key sites (e.g. liver 0.5±0.8 vs 1.2±0.9 in swine). Foam material properties were consistent between models (expansion: 37±3.9x vs 36±5.8x).

Conclusions: The use of recently deceased humans demonstrates a novel and unusual approach to device evaluation in representative human anatomy, particularly when tissue compliance is critical. Testing of other doses may identify an acceptable pressure with enhanced organ contact, and testing is ongoing at 100mL. This study is critical to the translation of promising foam findings in swine to clinical benefit.