Use this URL to cite or link to this record in EThOS:
Title: Using analytical and empirical techniques for improving medical device number entry systems design
Author: Cauchi, Abigail
ISNI:       0000 0004 7425 4767
Awarding Body: Swansea University
Current Institution: Swansea University
Date of Award: 2014
Availability of Full Text:
Access from EThOS:
Full text unavailable from EThOS. Please try the link below.
Access from Institution:
User interfaces that employ the same display and buttons may look the same but can work very differently depending on how they are implemented. In healthcare, it is critical that interfaces that look the same are the same. Hospitals typically have many types of visually similar infusion pumps, but with different software versions and variation between pump behaviour, and this may lead to unexpected adverse events. For example, when entering drug doses into two similar infusion pumps, different results may arise when pushing identical sequences of buttons. These differences arise as a result of subtle implementation differences and may lead to large errors that users do not notice. 'Differential formal analysis' is a new user interface analytic evaluation method based on stochastic user simulation. The method is particularly valuable for helping evaluate safety critical user interfaces, which often have subtle programming issues. This new approach starts with the identification of operational design features that define the design space to be explored. All combinations of design features are analysed by simulating keystroke sequences containing keying slip errors. Finally, each simulation produces numerical values that rank the design combinations on the basis of their sensitivity to key slip errors. Differential formal analysis is demonstrated through case studies of number entry systems, many of which represent a common safety-critical user interface styles found in medical infusion pumps and elsewhere. The results uncover critical design issues, and are an important contribution of this thesis since the results provide device manufacturers guidelines to improve their device firmware. The analysis is complemented with models of usage based on 1,362 days of use of number entry systems from 19 infusion pumps over a 3 year period in a UK hospital. This thesis also suggests some improvements to medical device logging, which will help further evidence-based improvement to medical device safety. Previously, empirical methods and analytic methods have been used independently to analyse and improve number entry system designs. This thesis identifies key contrasts in exploring number entry errors using laboratory studies and analytic methods. The implications of combining methods to more thoroughly analyse safety critical design are discussed.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available