Burst Pressure Testing and Modeling of a Novel Pleural Sealant
Kailey Bell, Emily Day, Brad Young, and Olivia O’Brien
This figure shows a methacrylated dopamine-conjugated alginate (Alg-Ma-Da) patch secured over a defect in a collagen substrate mounted on the previous burst pressure testing platform. Air is administered through the tubing until the collagen-patch combination fails.
The Weiss Lab is working to develop and test several formulations of pleural sealants that can be used to treat puncture wounds in the lungs. In order to take this technology from the bench to the bedside, mechanical testing, in vitro testing, in vivo testing, and eventually clinical trials will be needed. This project is focused on a specific mechanical test - burst pressure - which measures the maximum pressure that can be exerted on the patch before it breaks. Clinically, this value is relevant to the amount of pressure that the lungs exert on the patch during inspiration, thus it is critically important to understand these measurements in order to ensure that the technology is translatable to a real-life application.
The existing burst pressure machine that is currently in use does have some limitations as it is unable to test varying wound morphologies that would be seen in a real-life emergency setting. To accommodate this, the team aimed to restructure the existing machine by increasing the aperture size or hole where the air is administered. To confirm that the new machine would be as accurate as possible, the team consulted with an expert in fluid mechanics, Dr. Dubief. This updated machine is shown below. Several other changes such as user-friendly knobs and a clear securing plate as to clearly see the experiment were made as to make the experimentation as user friendly as possible.
This is a Solidworks drawing of the updated burst pressure machine and its increased size along with the specific aspects of the design.
Along with this new and updated machine, the team has been able to determine the parameters that would allow us to predict the dimensions of the patch that will lead to sufficient sealing. These parameters would be essential for use by medical personnel so that a sufficient patch could be chosen to save the patients life. A comprehensive experimental procedure has also been established, which is shown below, as to test the varying patch sizes on the given wound. In the upcoming semester, the experimentation portion of the project will take place where the machine will be used to test each of the patches according to the experimental procedure.
This figure depicts the new and comprehensive experimental procedure which will be used to test the efficacy of the patches.
To conduct this experimentation, burst pressure testing protocols will be utilized following the ASTM standard procedure. First, a piece of collagen is used to represent the punctured lung by creating a defect with a biopsy punch, and the patch is placed over the hole to seal it. Then, the sealed collagen is placed onto the burst pressure machine platform which supports the collagen but has a tube aligned with the sealant-covered defect area of the patch through which air can be administered via a syringe. The sealed collagen is held down around the airflow opening so that when the air comes through, the sealant-collagen complex is forced to hold all of the pressure, much like blowing up a balloon. As the pressure increases toward the maximum that the patch can withstand, the material will burst. This allows for the understanding of the patches behavior at and beyond physiological pressures.