In this proposal, we will demonstrate the feasibility of a Coaxial Femoral Cannula (CFC) for use in extracorporeal life support (ECLS) transport of wounded soldiers from far forward positions. Soldiers who develop acute lung injury (ALI) in combat zones cannot be immediately transported to advanced medical centers due to their tenuous respiratory condition and the hostile environments where they sustain their injury. ECLS can be used to support patients suffering from respiratory insufficiency or cardiopulmonary injuries. However, ECLS is only used in intensive care units (ICUs) due to system complexity, machine size, and the technical complexity involved with utilizing currently available cannulas for vascular access. ECLS is typically initiated at either a single vasculature access site using a dual lumen cannula inserted into the right internal jugular vein (RIJ) or at two access sites using single lumen cannulas inserted into the RIJ and a femoral vein (FV). However, these cannulation methods can be ergonomically challenging during patient transport; are challenging to insert and maintain position without advanced imaging; and are thus difficult to deploy in military situations even at a Role 3 combat hospitals, which deliver the highest level of care within the combat theatre. Despite this, the military has used ECLS to transport soldiers from Iraq and Afghanistan to Landstuhl Regional Medical Center in Germany. More recently, the DoD has focused on operating a centralized ECLS team out of the US, the San Antonio Military Medical Center (SAMMC). However, this results in standby times of 24-48 hours before highly trained staff can deploy to initiate ECLS for subsequent transport. Thus, there is a need to simplify ECLS cannulation to enable rapid initiation of ECLS in forward operating environments by personnel at combat medic levels of training. The CFC will allow for safe cannulation in far forward positions by GHOST teams, Forward Surgical Teams or by Role 3 medics with minimal resources. The CFC is designed for facile insertion under ultrasound guidance with little sensitivity to positioning. Its robust design will reduce insertion complications and the CFC allows the ECLS system to move with the patient either on the stretcher using current ECLS systems or strapped directly to the patients leg using the PAS transport system being developed by ART. This will enable early initiation of ECLS support to stabilize the patient while the dedicated ECLS team from SAAMC is enroute to transport the wounded warfighter to definitive care in the United States. In this proposal we will build durable prototype CFCs and test them in vitro. We will perform simulated cannulation and ECLS for 72 hours using a high-fidelity cannulation simulator to assess durability and the ability to place the CFC under ultrasound guidance. Then we will perform ISO 18193:2021 testing of: cannula kink resistance; integrity of the components; and cannula pressure drop.
