Effects of saline submersion at body temperature on airway supportive devices including a novel nasopharyngeal device produced using 3D-printing

Sarah A Raven; Nathan T Montgomery; Alyssa S Chen; Zahra Nourmohammadi; Jeffrey Plott; Albert Shih; Prabhat Koppera; David A Zopf

doi:10.1016/j.amjoto.2024.104366

Effects of saline submersion at body temperature on airway supportive devices including a novel nasopharyngeal device produced using 3D-printing

Am J Otolaryngol. 2024 Apr 29;45(4):104366. doi: 10.1016/j.amjoto.2024.104366. Online ahead of print.

Authors

Sarah A Raven¹, Nathan T Montgomery², Alyssa S Chen³, Zahra Nourmohammadi⁴, Jeffrey Plott⁴, Albert Shih², Prabhat Koppera⁵, David A Zopf⁶

Affiliations

¹ University of Michigan Medical School, Michigan Medicine, University of Michigan, 1301 Catherine Street, Ann Arbor, MI 49109, USA; Department of Otolaryngology - Head and Neck Surgery, Wayne State University, 5E UHC, 4201 St Antoine, Detroit, MI 48201, USA.
² Department of Mechanical Engineering, College of Engineering, University of Michigan, 2350 Hayward Street, Ann Arbor, MI 48109, USA; Department of Biomedical Engineering, College of Engineering, University of Michigan, 2200 Bonisteel Boulevard, Ann Arbor, MI 48109, USA.
³ University of Michigan Medical School, Michigan Medicine, University of Michigan, 1301 Catherine Street, Ann Arbor, MI 49109, USA; Otolaryngology - Head and Neck Surgery, Massachusetts Eye and Ear, Mass General Brigham, 243 Charles Street, Boston, MA 02114, USA; Harvard Medical School, 25 Shattuck Street, Boston, MA 02115, USA.
⁴ Department of Biomedical Engineering, College of Engineering, University of Michigan, 2200 Bonisteel Boulevard, Ann Arbor, MI 48109, USA.
⁵ Department of Anesthesiology, Michigan Medicine, University of Michigan, 1540 E Hospital Drive, Ann Arbor, MI 48109, USA.
⁶ Department of Biomedical Engineering, College of Engineering, University of Michigan, 2200 Bonisteel Boulevard, Ann Arbor, MI 48109, USA; Department of Otolaryngology - Head and Neck Surgery, Michigan Medicine, University of Michigan, 1540 E Hospital Drive, Ann Arbor, MI 48109, USA. Electronic address: davidzop@med.umich.edu.

PMID: 38729016
DOI: 10.1016/j.amjoto.2024.104366

Abstract

Purpose: This study investigated dimension changes of various nasopharyngeal airways, including a novel self-supporting device, after saline submersion at body temperature to simulate in-vivo use. Dimension changes over time may reduce efficacy during long-term use and require sizing adjustments or limits on duration of use.

Materials and methods: Cuffless Covidien endotracheal tubes, pediatric Rusch fixed flange polyvinyl chloride nasal airway tubes, pediatric Rusch Robertazzi style Mediprene nasal airway tubes, and novel silicone elastomer self-supporting nasopharyngeal airways were fully submerged in 0.9 % normal saline solution incubated at 37 degrees Celsius for 15 days. All devices had tube length and wall thickness measured after 0, 1, 2, 3, 4, 5, 10, and 15 days. The 95 % confidence intervals of tube dimensions at each date were compared with the 95 % confidence intervals at day 0.

Results: The Covidien ET tube, Rusch PVC NPA, and ssNPA tube lengths and wall thicknesses did not change significantly over 15 days. The Rusch Mediprene NPAs had a statistically significant increase in length starting at day 1 and wall thickness at day 2.

Conclusions: The novel ssNPA did not expand in the in-vitro environment, supporting its safety for extended use. The PVC NPA and ET tube dimensions also remained stable. However, the Rusch Mediprene NPAs had significant length expansion after 1 day of submersion, indicating a considerable risk of expansion during extended use with potential implications for patient care. Silicone and PVC NPA dimensions remained stable when saturated, indicating these materials may be more appropriate for extended use.

Keywords: 3-D printing; Airway obstruction; Endotracheal tube; Nasopharyngeal airway; Obstructive sleep apnea; Polyvinyl chloride.