A Study Of Medical Service Process Risk Assessment Based On Vague Set And Fault Tree Analysis

Ensuring patient safety has become the main duty of the whole medical system.Medical system is a typical high-risk system in the case of increasing technique complexity,Medical risk assessment and control directly affect patient safety.As millions of patients worldwide are unnecessarily harmed because of preventable medical errors per year,the importance of medical risk management is increasingly apparent.Medical risk assessment is the core of risk management,which has an important significance in risk identification,patient security,healthcare improvement.At present,researches on medical risk mainly depend on experts' experience analysis and the statistical analysis of clinical data,which need further investigation considering current research situation.Traditional fault tree analysis(FTA)can show the relationship between failures and influencing factors more clearly than other evaluation methods,and has obvious advantages on both qualitatively and quantitatively evaluating consequence events.Since the medical service process presents a polymorphism due to the effect of large number of stochastic,fuzzy and indeterminate factors,traditional FTA has to pull through on medical process-oriented risk assessment.Moreover,general risk evaluation methods are based on empirical data and the general output RPN(risk priority number)as the single risk indicator,which cannot evaluate the multi-dimensional performance of risk events comprehensively.A risk assessment approach integrated with TOPAZ model is proposed in this thesis by modeling a process-oriented fault tree and introducing vague set theory for the multi-state and uncertain probability of bottom events.The approach constructs a fault-tree model based on the analysis of specific medical process and the identification of operation and hazard in the risk analysis stage,and calculates the vague set probability of top event using diagnosis and treatment records,equipment reliability and experience data,etc..In the risk evaluation stage,the vague importance number is calculated to identify the key bottom events and can also produce a coordinate index,combined with the degree of severity and detection based on experts assessment.The comprehensive indicator can be used to evaluate the risk level of all events by calculating the distance to the origin in 3D coordinate system.The result of risk assessment provide decision support for medical risk control.The risk assessment of perioperative anesthesia process is took as an example.The vague set probability of anesthesia accident and the importance number of bottom events are calculated based on the fault-tree model of perioperative anesthesia accident.Further,the severity and detectable level of each basic event are evaluated and the comprehensive level of risk is also calculated.The form and accuracy of the results demonstrate excellent performance of the approach on medical process oriented risk assessment.