Capstone Week 9- Kierstin Parker
In Class:
Lab:
In the lab, on Wednesday I picked up the new 3d printed parts. I drilled a hole into the valve connector to allow fluid to flow through. The print lab accidentally printed the unscaled version, so I will have to submit the part. It gave me practice drilling though.
Alex and Brinkley helped me do the flow in parallel shakedown because we got the McMaster parts in. Only the .4 in resistor worked to allow flow through without the syringe bursting first. I will have to redraw and print parts for that.
I helped Fady test if the new sensor on the system was working by putting a needle valve on his old system to create resistance to see if the pressure readings were comparable. They were which is good. He is going to work on setting up the second resistor in the system and look into the conversion of millivolts to mmHg.
Solidworks:
I drew up more resistors in Solidworks. I drew them from .37 to .42 in increments of .01in. I submitted printing forms to the lab for this, as well as instructions to print the scaled-down version of the connector.
Meeting with Brinkley:
Ethics Presentation:
Set up the presentation outline, then started working on the ethics research.
Problem statement:
The Airway Kit containing Sheridan® Endotracheal Tubes was recalled. It was a Class I recall, the most serious type of recall because the use of this device may cause serious injuries or death.
The device is used to open the patient’s airway, provide ventilation, and administer anesthetic gas when a patient cannot maintain adequate respiratory function to meet their needs, such as while under general anesthesia during a surgical procedure. To do this, endotracheal tubes are used.
The reason for the recall was that the Sheridan endotracheal tube connector dislodged from the endotracheal tube, causing disconnection of the patient from the breathing circuit, which results in insufficient oxygenation, a decrease in vital signs, or death.
Four deaths and 18 injuries have been reported to Teleflex in association with disconnection.
The recall affects 80 kits and 70 components not included in kits that were distributed between Nov. 28, 2018 and June 5, 2019.
The problem was the 15mm connector. Although the connector can be removed, it should not disconnect from the endotracheal tube without significant force
In most reported cases, detachment of the connector was identified by clinical personnel or via an eventual decrease in ventilator circuit pressure which triggered ventilator alarms
https://www.teleflex.com/global/compliance/MCI-2019-0619_HR_Code_of_Ethics_English.pdf
Lab:
Once I got to the lab I realized the parts I drew up that went from .37 to .42 should have been from .47 to .52 in order to fit my part. Because of this, I couldn’t do the fluid flow with resistors in parallel shakedown with the .5in tubing. I tried to drummel down the bigger 3/d printed part so I could have one working connector, but the print wasn’t solid, so it ended up not working. The small one that Fady printed (black), ended up fitting perfectly in the small tubing used to show the three tubes in parallel, so I redesigned the connector to hopefully attach that to the 1/8id tubing so I can get a pressure reading on it.
Brinkley and I also tried connecting the tubes and creating a housing for it to replicate our design. When we put the resistors in the tubes we realized there was leaking so we cut off the housing to see where the leak was coming from. There was a puncture in the tube from where we had tried to glue it back (to replicate the shape of our design). I reattached tubes and then cut intentionally different-sized resistors to stuff in the tube. When the syringe was attached and pressure applied, the different tubes dripped at different rates, proving our concept of fluid in parallel.
In analyzing the drip rates of each tube I recorded this data:
For the first trial in the chart, there was no leakage and I applied a constant pressure that was high enough to have leakage in all the tubes. For the second trial in the chart, there was a leak in the tube right by the syringe, and I continually increased the pressure to show that the lowest amount of resistance leakage would increase, while the other tubes with higher resistance would also leak due to the high pressure.
Other things to do/ test:
-Epoxy the ends of the tubes and poke holes to see if it still has the same effect
-Maybe glue the silicone to the ends and poke holes to see if it has the same effect
-Connect tubes in parallel of the Ahmed valve size because we have pressure sensors that can read that size due to the needle connection used in the Ahmed benchtop test
-Maybe put epoxy around this shakedown to have a large prototype
- Test with low pressures to see that the tubes with higher resistances won't leak until the pressure reaches a certain point.
-Use one of the 3d printed resistors and drill holes to try and create a connection point for small tubes to connect. (Solidworks version of this shown later in the blog)
Solidworks:
Redesign of the valve to fit ⅛ in inner diameter and the tubing from the fluid flow with resistor shakedown:
Solidworks scratchwork for measurements ^
I sent Fady 2 sizes of this to print because for some reason the printing sizes have been a little off, so hopefully, after this print, I will have a good idea of how to scale the part.
Team discussion on what is working/ not working
Solidworks to create a connection for small Ahmed-sized tubing:
I will try to print without the holes and just drill them if a shakedown using one of the 3d printed resistors works with the shakedown. Glue tubing in holes and seal to create a connection system.
Lab with Brinkley:
I drilled holes in the resistors small enough to put the tubes in. There was a perfect sized drill bit, but it was too small for the drill so I had to size up. Brinkley and I made one epoxeyed connector with just the tubes stuck in the hole, and another where there was tape wrapped around the tube once to fill the hole space a little better.
The first picture (Above) shows the tape wrapped around the tube and inserted into the drilled connector. The second picture shows both of the connectors and tubes in the epoxy bath.
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