Medical devices are critical in the healthcare system and their failures can significantly impress the safety of patients, medical staff, and clinical engineers. With increasing COVID-19 pandemic in recent months, it is more necessary to assess the risks of the devices to avoid infection for patients, death, and severe hurts due to inactive and breakdown devices. The aim of this study is to assess medical device risks in general and pandemic situations with three main factors of the Failure Model Analysis Effect include occurrence, detection, and severity. Some sub-factors are defined and weighted using the Fuzzy DEMATEL and Fuzzy Best-Worst Method. Consequently, the weighted FMEA score of each failure is calculated as the Weighted Risk Priority Number. Finally, steady-state probabilities of very low and low failures are calculated to consider the changes during the time. Results show that near half of the failures are scored in very low and low levels but in the long term, most of them transfer to medium level risk. It can be concluded that some preventive maintenance plans for these kinds of failures to avoid occurring the higher risk level for them in the future is necessary and the results can help medical device managers.