Usability testing of a prototype Phone Oximeter with healthcare providers in high- and low-medical resource environments.

To increase the use of pulse oximetry by capitalise on the wide availability of mobile phones, we have designed, developed and evaluated a prototype pulse oximeter interfaced to a mobile phone. Usability of this Phone Oximeter was tested as part of a rapid prototyping process. Phase 1 of the study (20 subjects) was performed in Canada. Users performed 23 tasks, while thinking aloud. Time for completion of tasks and analysis of user response to a mobile phone usability questionnaire were used to evaluate usability. Five interface improvements were made to the prototype before evaluation in Phase 2 (15 subjects) in Uganda. The lack of previous pulse oximetry experience and mobile phone use increased median (IQR [range]) time taken to perform tasks from 219 (160-247 [118-274]) s in Phase 1 to 228 (151-501 [111-2661]) s in Phase 2. User feedback was positive and overall usability high (Phase 1--82%, Phase 2--78%). Anaesthesia