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Detachable Bronchoscope

Spring 2019 MAE 156B Sponsored Project

University of California, San Diego

Sponsored by Frank Talke (Ph.D.)

Executive summary: View

Background:

A bronchoscope is a medical device utilized in a medical procedure in which an endotracheal tube (breathing tube) is inserted into a patient to intubate them. A problem associated with this medical procedure is that the placement procedure of the endotracheal tube must be repeated if the wrong size endotracheal tube is being used. Repeating the placement procedure results in a delay of several minutes. While this amount of time does not seem lengthy in most settings, it can result in the death of a patient in emergency situations. The need for urgent endotracheal intubation occurs with regular frequency; it is highly desirable to reduce the amount of time associated with the placement procedure.

Figure 1: Use of bronchoscope on a patient

Objectives:

The primary objective of this project is to create a bronchoscope that features a detachable insertion tube, in order to reduce the amount of time required in the replacement of an endotracheal tube, while maintaining the features of a fully functioning conventional bronchoscope. The distal end of the bronchoscope must be able to deflect 180 degrees in opposite directions while being able to maintain ints position during detachment. The insertion tube must feature a reliable and durable connection to the control handle in order to avoid deficiencies in the functionality of the device. Furthermore, the connections for electrical components within the device must be able to disconnect and reconnect in the same manner.

Figure 2: Detachment of bronchoscope occurs at red line

Final Design:

Figure 3: Overall Prototype CAD

The bronchoscope is comprised of two main sections: the control handle and the insertion tube. The control handle chassis was 3D printed using a Connex printer, and houses the detachment mechanism and drivetrain controller. The insertion tube has a proximal end that contains the drive train, and an articulating distal end. When the insertion tube is mated with the control handle, a thumbwheel on the handle allows the operator to adjust the position of the distal end. An LED circuit was setup to demonstrate the ability for electrical connections.

Performance Results:

The iterated prototype was able to demonstrate a detachment capability and a transfer of motion from the control handle to the distal end of the insertion tube at a 1:1 scale. A single electrical connection was successfully made within the control handle as well. The first iteration of the prototype was unable to successfully move the angulation wires. This was due to misalignment between the bevel and pinion gears in the fabrication process. Additionally, the bearings used to support the shaft movement of the gears were not the right fit, creating slop. To reduce slop, the bearings were replaced with machined bushings.