Abstract:

This paper presents the development of two 3D printed models of lungs from 1) CT1 scan of a collapsed/punctured lung (pneumothorax) and 2) CT2 scan of the same lung, six weeks later, after it was healed. CT1 was with an IV contrast agent and a slice thickness of 2.50mm. CT2 was without an IV contrast agent and a slice thickness of 2.50mm. The 3D printed models are being used in training acute care nurse practitioner students in the College of Nursing at the University of Alabama in Huntsville. Each 3D printed model included both lungs (a good lung and a collapsed lung) and the thorax. The patient was a sixteen year old, male mountain biker who crashed his bike and suffered three broken ribs and a collapsed lung. A collapsed lung occurs when air enters the pleural space which is the area between the outside of the lungs and the inside of the chest wall. A hole in the lung allows air to escape from inside the lung and inflate the pleural space. 3DSlicer was used to rapidly and easily segment the lungs and trachea and to convert the DICOM (Digital Imaging and Communications in Medicine) formatted CT (computed technology) scans into STL (stereolithography) files. Specifically, the paint and grow from seeds options in 3DSlicer Segment Editor was used to segment the lungs. Very little cleanup was necessary of the STL files because of the sharp contrast between the lungs (which were black) in the CT scans and the chest walls. No 3DSlicer smoothing algorithms were applied to the segment models; consequently, the tears and punctures in the lungs were more visible. 3DBuilder software was used to view and make any additional cleanup to the models before printing. PrusaSlicer software was used to generate the G-code for printing the models on a Prusa i3MK3. The 3D models were printed at 90% scale to fit the Prusa print volume. The print time for one lung was 43 hours. In-fill density was 15% and layer thickness 0.15mm. One lung used 346g of filament with 30% waste for support structures. The treatments for pneumothorax include supplemental oxygen, needle aspiration, or chest tube drainage. During needle aspiration a syringe is used to remove some of the air in the pleural space. For a larger pneumothorax a hollow tube is placed in the chest to reduce air in the pleural space. The 3D printed models of the lungs are being used with the chest tube and needle decompression task trainer to teach acute care nurse practitioner students to insert a chest tube and use needle decompression techniques to re-inflate the lungs. The trainer uses needle decompression air reservoirs to provide the realistic release of air that is heard when the needle enters the pleural space. The needle is inserted through the pad replicating the pleural membrane and then into the pleural space providing a “pop” indicating the procedure was performed correctly. Surgical insertion of a chest tube is a complex procedure that can result in life-threatening complications to the patient. The task trainer allows students to practice until competence is achieved with precision and safety in a safe environment prior to performing the procedure in clinical practice on real patients. The 3D printed models provided an additional tool in the training. Included in this paper are a description of a pneumothroax, the use of the chest tube and needle decompression trainer, the development of the 3D printed models of the collapsed and healed lung and lessons learned.

Keywords:

3D printed model, collapsed lung, punctured lung, 3DSlicer.