Application of System-Theoretic Process Analysis for Enhancing Safety in a Ventilator System

Area of Science:

• Biomedical Engineering
• Healthcare Safety
• Systems Engineering

Background:

• Ventilator-related medical accidents are a persistent issue in Japan, stemming from equipment malfunctions and human errors.
• Existing analytical methods for medical device safety often lack the necessary rigor for comprehensive analysis.

Purpose of the Study:

• To explore the application of System-Theoretic Process Analysis (STPA) for ventilator safety.
• To identify potential hazards from human errors and device failures.
• To establish system-level safety constraints for ventilators.

Main Methods:

• Utilized STPA to construct a control structure diagram of a ventilator system.
• Identified Unsafe Control Actions (UCAs) and hazardous scenarios from a system-wide perspective.
• Analyzed system interactions to derive safety constraints for risk reduction.

Main Results:

• STPA successfully identified UCAs and system-level interactions leading to hazardous outcomes.
• The STPA methodology proved systematic and comprehensive, surpassing retrospective Critical Incident Reports (CIR).
• Identified mechanisms of incident causation, considering human and technical factors, and provided a basis for preventive measures.

Conclusions:

• STPA provides a holistic framework for ventilator safety, effectively addressing complex human-technical interactions.
• This approach enhances ventilator safety, improves risk management, and fosters a stronger safety culture for medical devices.