The interviewees consisted of 6 medical professionals with experience in emergency rescue:

• Kyung-Soon Kang(강경순): A Professor at Gachon University’s Department of Emergency Medical Services, President of the Korean Association of Professional Emergency Care, and Visiting Professor at the National Fire Service Academy. He has been active in the emergency medical field since 1995 and served as a founding member of Samsung Group’s 3119 Rescue Team, Korea’s first private rescue organization. He also developed the first disaster emergency response program and participated in major disaster scenes, including the Sewol ferry incident.

• Yoon-Hwa Oh(오윤화): A paramedic with 13 years of experience. She worked in the emergency room at Samsung Medical Center and is currently serving on an ambulance team.

• Gil-Yeon Heo(허길연): A nurse with 21 years of experience at Samsung Medical Center. She has also served as a disaster education instructor at the Armed Forces Nursing Academy.

• Young-Rae Noh(노영래): A nurse with 27 years of experience at Samsung Medical Center. She has worked in the surgical intensive care unit and the stroke center.

• Da-Yoon Kwon(권다윤): A nurse with 7 years of experience at Samsung Medical Center. She specializes in handling emergency situations in cancer surgeries.

• Jung-Hyuk Lee(이중혁): A nurse with 10 years of experience at Yonsei University Medical Center. He has expertise in emergency response for respiratory diseases.

A comprehensive explanation of the Golden Capsule was provided.

The features of the Golden Capsule were illustrated and categorized into four key sectors:

• product structure

• manufacturing process

• distribution and storage

• application in emergency rescue operations

Interviewees were given the opportunity to observe and interact with a physical prototype of the device during the evaluation process.

A large monitor was used to present experimental videos of the Golden Capsule to the interviewees.

First, a low-fidelity experimental video was shown to intuitively convey the conceptual principles of the device.

This was followed by a high-fidelity experimental video, which detailed the specific experimental methods, adding credibility and depth to the explanation.

Interviewees were assigned predefined tasks, and their interactions with the prototype were closely observed to gather insights and identify key findings.

In the heuristic test, 24 questions were provided, allowing the interviewees to evaluate the device using a 5-point Likert scale.

The A/B Test consisted of two evaluations:

• 1st Evaluation:

  A preference test was conducted between the traditional IV device (A) and the Golden Capsule (B). Participants were guided through usage scenarios covering nine stages—portability, fluid type identification, setup, placement during infusion, flow rate adjustment, monitoring infusion status, infusion completion, and post-treatment procedures—to compare the efficiency and usability of the two systems.

• 2nd Evaluation:

  This A/B test was performed to refine specific design elements of the Golden Capsule. Interviewees were asked to select their preferred design, focusing on exterior graphics and flow rate adjustment indicators to identify the most favorable options.

Additionally, a set of pre-prepared questions was presented to the medical experts to facilitate further discussion. This process was guided by Jakob’s Ten Usability Heuristics as a reference framework.

The additional questions included the following:

1. 시스템 상태의 시각화 (Visibility of system status) 

2. 시스템과 현실 세계 일치 (Match between system and the real world) 

3. 사용자 제어와 자유 (User control and freedom) 

4. 일관성과 표준 (Consistency and standards) 

5. 오류 방지 (Error prevention) 

6. 기억보다 직관 (Recognition rather than recall) 

7. 사용의 유연성과 효율성 (Flexibility and efficiency of use) 

8. 미학적이고 간결한 디자인 (Aesthetic and minimalist design) 

9. 오류 인식, 진단, 복구 지원 (Help users recognize, diagnose, and recover from errors) 

10. 도움말 및 설명 문서 (Help and documentation)