Final Design

Significance

The combination of laryngotracheal stylet and cannula functions as one connected device. The current procedure of intubation is inefficient due to multiple components, which creates unnecessary risk for a patient. This device is designed with the desire to eliminate this risk as well as reduce the amount of time that intubation takes. Often, this procedure occurs in emergency situations or in instances of trauma, so reducing the amount of time helps to save lives by providing a clear airway to those that cannot breathe on their own. With an outer diameter of 5mm, the device fits within all adult endotracheal tubes with 1mm of radial tolerance. This tolerance assists in the ease of insertion/retraction. Furthermore, the length is sized to fit the largest size of endotracheal tubes, thus ensuring proper coverage of the lidocaine spray without excess intrusion into the patient.

Functional Requirements

The following requirements are for the characteristic of the design direction in large.

• • Rigid but bendable, so the anesthesiologist can precisely shape device

  • Connect to interchangeable syringes with a luer lock system

  • Have a sleek and aesthetic design for marketability and manufacturability

  • Use of body-safe and sterile materials

  • Numbers of aperture or atomizer for anesthetic administration

Overview of Components

There are four major parts to this device: Luer lock, polyethylene tubing, internal malleable stylet, and atomizer. The flow of anesthetic occurs in the order stated previously. 

A Luer lock, also known as a Luer taper, is a standard connection method used in the medical field. This was chosen in order to allow for the laryngotracheal stylet and cannula to connect to any syringe, therefore allowing for any anesthetic type to be used. 

Hollow Polyethylene tubing is used as the main shaft of the device. It is hollow in order to allow for free flow of the anesthetic. Polyethylene is a low friction plastic that allows for easy maneuverability within an endotracheal tube. 

The internal malleable stylet, made of medical-grade Stainless steel 304, is placed within the Polyethylene tube. At a substantially smaller radius than the tube, the stylet does not block the anesthetic flow, but accomplishes its purpose of providing a rigid guide for an endotracheal tube. 

An atomizer is placed at the bottom of the laryngotracheal stylet and cannula, and it’s function is to turn the chosen anesthetic into a fine mist. The atomizer’s purpose is to more efficiently apply anesthetic to the patient’s throat. The length of an atomizer is relatively small in order to avoid harm to the patient's throat. 

Dimensions

Another important note is the device’s dimensions. The laryngotracheal stylet and cannula is designed to be used by endotracheal tubes of varying sizes. Considering a patient’s health, this is necessary. The laryngotracheal stylet and cannula’s outer diameter is manufactured to create minimal friction within any of these tube’s, ensuring no complications from snagging or excess time to administer the device. Another aspect to consider is the device’s length, which is designed to minimize the distance that the tip (atomizer) protrudes from the endotracheal tube. The purpose of this element is to minimize risk to the patient’s throat that may occur from protruding too far. The endotracheal tube inner diameter ranges from 6-9mm, with a length 28 cm to 33 cm. 

Design

For our device, there are three critical factors that must be satisfied for our device. Figure X shows the breakdown from these factors to our final design, with the addition of dimensional optimization to reduce Lidocaine volumetric losses.

Figure 1. Block Diagram of Design Stages

(with a focus on the three most crucial deliverables for the device)

Figure 2: Render of the Finished Device

As can be seen in the finished model, the polyethylene tube and stainless rod provide rigidity to the entire device, while the luer lock allows a connection between the syringe and the atomizer. It is important to note that the lidocaine does come in direct contact with the inner rod; therefore, the material was chosen to be body safe.

Figure 3: Rendering of the Device Inserted into an Intubation Tube 

(The device sits at the boundary of the intubation tube, so that is not intrusive to the patient while allowing for optimal spray coverage)

With an outer diameter of 5mm, the device fits within all adult endotracheal tubes with 1mm of radial tolerance. This tolerance assists in the ease of insertion/retraction. Furthermore, the length is sized to fit the largest size of endotracheal tubes, thus ensuring proper coverage of the lidocaine spray without excess intrusion into the patient.

                                                                                                                                       Figure 4. Final Design of Device