Design Requirements for a Nitroglycerin Dose Titration Decision Support System: User-Centered Design Study

Background: Nurses titrate intravenous infusions of nitroglycerin for acute relief of angina by manually increasing or decreasing the dose. Titration can be a difficult task because doses that are too high may result in hypotension arising from peripheral vasodilatory effects of the medication. Likewise, a dose that is too low may result in inadequate pain relief. Clinical decision support systems that predict changes in blood pressure for nitroglycerin dose adjustments may assist nurses with the titration process.

Objective: This study aimed to design a user interface for a clinical decision support system for nitroglycerin dose titration (nitro DSS).

Methods: This study used a user-centred design that consisted of an initial qualitative study with semi-structured interviews to identify design requirements for prototype development, followed by three rounds of usability testing. Nurses with experience titrating nitroglycerin infusions in
coronary care units participated. Three iterative usability testing cycles, which involved participant observation, questionnaires, and interviews, were undertaken to evaluate the usability and acceptability of the nitro DSS.

Results: A total of 22 nurses participated, including seven during the qualitative study and 15 nurses during usability testing. Analysis of the qualitative data revealed four themes for the interface design to be: (1) Clear and Consistent, (2) Vigilant, (3) Interoperable, and (4) Reliable.
Usability testing revealed ways to improve the interface to enhance the usability and acceptability of NITRODSS. The major elements of the final prototype included a feature for viewing the predicted and actual blood pressure over time to determine the reliability of the
predictions, a drop-down option to report patient side effects, a feature to reject the potential dose and report reasons for rejecting, and a visual alert indicating any systolic blood pressure predictions below 90 mm Hg. Nurses’ ratings on the questionnaires indicated excellent usability and acceptability of the final nitro DSS prototype.

Conclusions: This study successfully applied a user-centred design approach to collaborate with nurses in developing a user interface of nitro DSS that meets the needs of the nurses. Future studies are needed to evaluate the effectiveness of using this system in clinical practice.