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Jennifer Hayden — 2012-13 Fellow

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Project Description
This research is aimed at developing an improved way of controlling blood loss in surgical procedures and particularly in trauma situations. Specifically, we are developing a hermetically sealed fluid management system that will permit surgery to be performed within a localized aqueous environment. The proposed aqueous immersion surgical system (AISS) is envisioned to become a platform technology that will ultimately be tailored to many specialties, and has application for both Earth and space-based use. The AISS concept is a dome made of optically clear polymer (e.g. polycarbonate) that is attached to tissue surrounding the surgical site forming a watertight seal. Several access ports strategically placed on the surface of the dome allow the surgeon to perform a procedure in a manner similar to endoscopic surgery through trocars. Additionally, feedback controlled fluid management (irrigation and suction) will be incorporated to provide mild extravascular pressure and remove debris. The AISS is founded upon 3 separate hypotheses:

  1. Moderate hydrostatic pressure will minimize or even stop bleeding without occluding surrounding vessels because of the tethering provided by soft tissue that surrounds the vascular anatomy,
  2. Continuous fluid cycling will improve surgical field visualization and aid in locating hemorrhage sites, so in cases where bleeding is severe the surgeon can employ alternative hemostatic methods. This is particularly helpful in a trauma situation, and
  3. The fluid suction mechanism is an ideal debridement tool.

The ultimate goal of our research is to demonstrate safety and efficacy of the proposed system in a validated animal model, suitable for manufacturing scale-up and commercialization.

Approach and Methodology
Preliminary mock surgical experiments using porous tissue analog materials support hypotheses 1 and 2. Our next milestone is to develop and implement isolated tissue models using organs obtained from a local abattoir for further proof-of-principle demonstration. We aim to characterize the bleeding and pressure-to-hemostasis profiles of various porcine tissues including the heart, spleen, kidney, liver, and brain – chosen due to their size (ease of use, immediate availability, similarities to human anatomy) and because using tissue from animals sacrificed for consumption allows us to reduce the number of laboratory animals used.

Each of the aforementioned organs will be placed in a water-tight chamber, and after establishing perfusion, standardized traumas will be inflicted on the organ to create a hemorrhage. We will then apply external hydrostatic pressure to staunch the egress of blood. Endpoints will be both the degree of bleeding and the maintenance of tissue perfusion, measured by venous blood flow.