A systems-theoretic hazard analysis for safety-critical medical gas pipeline and oxygen supply systems

Medical gas systems are safety-critical systems due to their association with critical care situations. In particular, the oxygen gas supply system contains many complications represented in the interactions between human and equipment while operating the system and managing emergencies. Therefore, it contains many hazards that require high safety standards to maintain the integrity of the system. The traditional hazard analysis methods suffer from weaknesses as their linear reasoning assumption cannot adequately describe the actual behavior of modern socio-technical systems that are characterized by tight couplings and complex interactions among technical, human and organizational aspects. Alternatively, Systems Theoretical Process Analysis (STPA) is a new hazard analysis approach that accounts for the causal relationships between system components and their unsafe interactions, allowing the integration of both occupational and process safety. STPA is widely used in the automotive, aviation, and aerospace industries whereas there are a few applications of STPA in healthcare domain. This paper proposes the use of STPA methodology in analyzing the hazards related to the medical gas pipeline and oxygen supply systems in a low-medium income country. Specifically, the analysis considers the emergencies that stem from the total or partial failure of oxygen supply and the hazards related to temporary restoration of the medical oxygen system. The results indicate that STPA contributes to identifying the hazards resulting from the interference between the human, machines, and equipment, and studying the unsafe effect of the system elements on each other. This research suggests control measures to prevent the unsafe interaction of the system components and improve the response time to oxygen failure incidents, which greatly reduces the potential consequences.