Implementing smart materials and technologies for medical emergency airway access devices

Siena, F.L. ORCID: 0000-0002-6908-7365, 2019. Implementing smart materials and technologies for medical emergency airway access devices. PhD, Nottingham Trent University.

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Airway management and intubation procedures continue to challenge anaesthetists daily. Failure to secure the airway with an endotracheal tube in a timely manner upon induction of anaesthesia can lead to serious complications, including death or disability. Most anaesthetists consider endotracheal tube introducers (bougies) as essential equipment; however, there are many different types with relatively little performance data to help anaesthetists make an informed choice. Standard bougies have a requirement to be reshaped multiple times in an attempt to create the desired navigation path of the endotracheal tube. Manoeuvring within the trachea presents significant navigation and control challenges whilst attempting to minimise trauma. Improvements in airway management care is often facilitated by the introduction of new or improved airway management equipment, however understanding their physical properties is imperative for the development of an improved device. This research addresses the development of a new emergency airway access device; the steerable bougie has been designed to enhance device control and improve the speed and the safety of bougie guided endotracheal intubation.

Initial work focussed on assessing the case of need for the development of an improved bougie, in addition to identifying design criteria and specifications. A number of anaesthetists were surveyed and identified increased manoeuvrability in-situ, improved shape retention and steerable control as desirable device attributes. Initial design, development and testing explored the feasibility of actuators and smart materials capable of replicating a steerable movement. Initial prototyping and testing demonstrated that flexible steerable tips controlled by Flexinol® actuator wires could effectively control the navigation of the tip.

Understanding the physical properties of bougies is fundamental to patient safety, device operation and ultimately equipment procurement decisions. Accurate and reliable bougie safety performance data, including perforation forces, bougie tip pressures and shape retention is not available. Equipment evaluations often fail to consider key testing criteria including testing equipment specifications. Tip pressure studies conducted identified current equipment weaknesses with airway trauma, including significant mucosa damage and perforation easily achieved by low tip pressure forces. The steerable bougie demonstrated significantly lower tip pressure forces compared to commercially available bougies. Repeatability testing conducted assessing tip pressure performance identified variable degradation over time for all commercially available bougies; the developed steerable bougie presented limited degradation over time.

Anaesthetists define shape retention as a critical performance characteristic for a bougie. To match the curvature of a patient's airway multiple bougie shaping iterations are usually required, however bougies often return to their original shape within seconds of being manipulated. All bougies present initial snap back and shape loss. To identify bougies with optimal shape retention, an innovative Shape Retention Testing System (SRTS) was designed and built to test shape retention characteristics. Testing demonstrated that bougies with dual or multi-lumened structures provided the highest level of shape retention hold. The steerable bougie outperformed the commercially available bougies at most shaping distances, demonstrating limited shape loss.

Utilising the accumulated bougie performance data, a steerable bougie with improved shape retention, reduced tip pressures and reduced likelihood of causing airway trauma has been developed. The steerable bougie is connected to an ergonomically designed controller attached to a laryngoscope that can also be easily attached/detached and sterilised.

This research has demonstrated that a steerable bougie with augmented physical properties can be developed that not only provides medical professionals with a device that has increased steerability and usability for time critical procedures but will also reduce the likelihood of patient airway trauma.

Item Type: Thesis
Creators: Siena, F.L.
Date: January 2019
Rights: This work is the intellectual property of the author. You may copy up to 5% of this work for private study, or personal, non-commercial research. Any re-use of the information contained within this document should be fully referenced, quoting the author, title, university, degree level and pagination. Queries or requests for any other use, or if a more substantial copy is required, should be directed towards the owner of the Intellectual Property Rights.
Divisions: Schools > School of Architecture, Design and the Built Environment
Record created by: Linda Sullivan
Date Added: 03 Jul 2019 15:00
Last Modified: 10 Jan 2023 09:20

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