Final Design
The final deliverable can be seen below in figures 3 and 4, which shows the 3D CAD depiction of the elbow clip on SolidWorks, as well as the final prototype that was 3D printed for the purposes of MAE 156B. The final array of clips printed, were done so in a PMMA acrylic used by the Stratasys Printer the Connex 3. This material has been rigorously tested throughout the course of this project, and has been determined to be a possible candidate for use inside a patient.
Having identified the two most important aspects of the material, other material options have been recommended as options for mass manufacturing once the device is ready to be used. These material options are: PET (Polyethylene Terephthalate), and PEEK (Polyether Ether Ketone).
The PMMA acrylic used throughout the course of this project has been tested and determined as strong enough to remove approximately 45% of the pressure from the posterior larynx, proving the usefulness of this device. It is believed that with PMMA, or any of the alternatively suggested materials, the “Elbow Clip” Endotracheal Tube Support System could prove to be a useful device to use while patients are comatose, or even during simple outpatient surgery.
The design utilizes three prongs, which wrap around the tube, with the shape and size of these prongs determined to be ideal to maintain enough strength to hold the tube to the desired bend, while also allowing for the clip to bend slightly to the restorative force of the tube in order to avoid fracturing.
Elbow Clip Design
Application video of Final Elbow Clip Design
IMG_2759.MOVDesign Feature
The clip has a thickness of 1mm, and an inner diameter of 9.4 mm for a 7.0 size tube. In general, the inner diameter of the clip is 0.1 mm smaller than the outer diameter of the endotracheal tube.
There are three openings along with the clip in order to optimize our material required per clip, and to marginally increase the flexibility to account for the restorative force of the tube.
We designed clips with different angles from 85-degrees to 115-degrees to fit different needs. The user could apply multiple clips in series to create more types of tube bending to fit the patient's circumstances.
Application Standard
Our current material choices are semi-compatible. According to USP Class VI and ISO 10993 the acrylic material we have used in past iterations of testing with ratings of up to 24 hours mucous membrane contact.
The clip is designed for one-time usage only. Under the consideration of safety and patient health, we recommend replacing the clip after each intubation.
Used clips should be processed with the Hospital, Medical, and Infectious Waste Incinerators (HMIWI).
The design is user-friendly and easily applicable to any medical technician. The clip should be applied after the intubation and taken out before removing the endotracheal tube.
Clip Angle-Tube Bending Relationship ---Angle Sensor Test
Potential Problem:
Clip Angle and tube bending angle do not match. For example, the 90-degree clip doesn’t create 90-degree bending.
Objectives:
Figure out the relationship between clip angle and tube bending so that users could make quicker choices accordingly.
SetUps:
The flex sensor that is attached to the Arduino to measure the bending angle of the tube.
The collected data is used to analyze the relationships between clip angle and tube bending angle through Matlab.
Figure 3 and 4 below present the setups of the angle sensing experiments
The angle that is the tube bend is the angle between tube and horizontal line.
The tube bending angle is the bending that tube currently has.
The angle that tube bend = (180º - tube bending angle).
Like figure 5 presented. The larger the clip angle, the tube bend far away from horizontal.
Result:
Despite the error caused by operation, environment noise and limitation of the accuracy. There is a negative relationship between clip angle and Tube bending angle.
The tube will bend 7° away from horizontal for each 10° increase in the clip angle.