[Design of a dedicated connecting tube for extracorporeal carbon dioxide removal therapy].

Extracorporeal carbon dioxide removal (ECCO2R) is a type of extracorporeal circulation technology. It generally refers to a technique that mimics the modality of veno-venous extracorporeal membrane oxygenation (VV-ECMO), aiming to eliminate carbon dioxide from the blood and correct hypercapnia with a relatively low blood flow. The removal efficacy of ECCO2R depends on blood flow, gas flow rate, membrane lung surface area, and the partial pressure gradient of carbon dioxide (PCO2) across the membrane. Currently, the surface area of gas exchangers used in clinical practice is generally less than 1 m2. Therefore, ensuring the achievement of the target blood flow during ECCO2R therapy is crucial to its effectiveness. However, the catheters currently available in clinical settings fail to deliver a blood flow of 400-500 mL/min, necessitating technical improvements. To address this clinical challenge, the medical staff of critical care medicine department of Zhongda Hospital, Southeast University designed a dedicated connecting tube for ECCO2R therapy, which has been granted a National Utility Model Patent of China (ZL 2023 2 2120568.4). The main structure of this dedicated tube comprises three central venous catheters arranged in a Y shape: central venous catheter 1, central venous catheter 2, and central venous catheter 3. Catheters 1 and 2 are connected in parallel, and in series with catheter 3. The front-end connectors of catheters 1 and 2 are fitted with sterile protective caps, while the rear end of catheters 3 is equipped with a membrane lung connector for connection to the membrane lung. Separate side tubes are attached to the outer sides of catheter 1 and catheter 2 respectively, for connecting irrigation fluid, releasing pressure in the blood drainage segment, and shortening the pause time of extracorporeal circulation during ECCO2R. Clamps are installed on the catheter 1, catheter 2, catheter 3, and the side tubes. The dedicated connecting tube for ECCO2R features a simple in structure, easy to operate, and highly practical. The improved connecting tube can achieve a blood flow of 400-500 mL/min, which ensures the therapeutic effect of ECCO2R and renders it suitable for clinical promotion.