Continued Development and Testing of a Novel Steerable Chest Tube, Extendable Infusion Cannula, and Portable Suction-Infusion Pump for Use in Austere and Transport Environments to Prevent Retained Hemothorax.

With blunt and penetrating trauma to the chest, warfighters frequently suffer from hemothorax. Optimal management requires the placement of a chest tube to evacuate the blood. Malposition of the tube may be a causative factor of inadequate drainage (retained hemothorax). As a potential solution, we developed a previously reported steerable chest tube allowing accurate placement into a desired location to enhance effectiveness. To provide assisted aspiration, we developed a portable, battery-operated suction device capable of simultaneous or sequential infusion. This report details the ongoing progress of this project. Updated steerable tube and pump prototypes were designed and produced. The tubes were tested for feasibility in two pigs and one cadaver by fluoroscopically comparing tip positions after insertion by a number of providers. Measured drainage volumes comparing standard vs. steerable tubes after pleural infusion of 1,000 mL of saline in two pigs were compared. Testing of the pump focused on the accuracy of suction and volume functions. The steerable tube prototype consists of sequentially bonded segments of differing flexibility and an ergonomic tensioning handle. The portable suction pump accurately provides up to 80 cmH2O of suction, an infusion capability of up to 10 mL/min, and a 950 mL removable reservoir canister. After minimal training, providers easily and repeatedly placed the tip of the steerable tube in the lateral diaphragmatic sulcus in animals and cadavers. Arc was limited to the distal segment. Compared to a standard tube, the steerable tube placed along the diaphragm improved pleural fluid drainage volumes by 17%, although this did not reach statistical significance in six trials. These new prototypes represent substantial improvements and were performed according to expectations. We believe that this steerable chest tube and portable suction-infusion pump can be effectively used for warfighters with chest injuries in austere environments.

Optimal Initial Positioning of Chest Tubes to Prevent Retained Hemothorax Using a Novel Steerable Chest Tube With Extendable Infusion Cannula.

INTRODUCTION: With blunt and penetrating trauma to the chest, warfighters and civilians frequently suffer from punctured lung (pneumothorax) and/or bleeding into the pleural space (hemothorax). Optimal management of this condition requires the rapid placement of a chest tube to evacuate as much of the blood and air as possible. Incomplete drainage of blood leading to retained hemothorax may be the result of the final tube tip position not being in contact with the blood collections. To address this problem, we sought to develop a "steerable" chest tube that could be accurately placed or repositioned into a specific desired position in the pleural space to assure optimal drainage. An integrated infusion cannula was added for the instillation of anticoagulants to maintain tube patency, thrombolytics for clot lysis, and analgesics for pain control if required. MATERIALS AND METHODS: A triple-lumen tube was designed to provide a channel for a pull-wire which was wound around an axle integrated into a small proximal handle and controlled by a ratcheted thumbwheel. Tension on the wire creates an arc on the tube that allows for positioning. In vitro testing focused on the relationship between the tension on the pull-wire and the resultant arc. Two adult cadavers and two anesthetized pigs were used to study the feasibility of accurate tube placement. After a brief training session, providers were asked to place tubes inferiorly along the diaphragm where blood was anticipated to accumulate or at the apex of the lung for pneumothorax. Success was determined with fluoroscopic images and was judged as a tube tip lying in the targeted position. RESULTS: The design was prototyped with an extruded polyvinyl chloride multilumen tube and a 3D printed tensioning handle. In vitro studies showed that one turn of the thumbwheel created 70° to 90° of arc of the tube. Cadaver and animal studies showed consistent success in the desired placement of the tube at or near the lateral diaphragm or in the apex. Attempts were also successful by surgical residents with minimal training. CONCLUSIONS: Initial preliminary studies on a novel steerable chest tube have demonstrated the ability to appropriately position the tube in a desired location. The addition of an extendable cannula will allow for safe clot lysis or maintained tube patency. Additional studies are planned to confirm the benefit of this device in preventing retained hemothorax.