Importance of practical simulation training for troubleshooting the heart-lung machine

Abstract

The artificial heart-lung system is a device that replaces the patient’s respiratory and circulatory function during surgery on the heart and great vessels. Users must operate the system by properly recognizing and appropriately evaluating various types of information and by providing feedback to the machine; inappropriate interaction between humans and the machine can cause failures. A questionnaire survey showed that the incidence of problem events during the operation of heart-lung machines was 1/300 to 1/100, both within and outside Japan, and that severe events such as permanent disability or death occurred at an incidence of 1/1000 to 1/500. It has been generally reported that the following measures are effective ways of reducing errors: (1) reducing the number of high-risk operations (risk minimization), (2) reducing the probability of occurrence of errors during each operation (probability minimization), (3) implementing multiple error-detecting measures (multiple detection of errors), and (4) having the capacity to minimizing damage (damage limitation). This article discusses effective countermeasures as a result of a questionnaire answered in Japan. The first measure to be taken is to provide both software (i.e., manuals that describe safety measures, checklists, and troubleshooting approaches that are not otherwise readily available) and hardware (i.e., necessary monitoring devices that enhance safety). Second, a standard heart-lung circuit needs to be designed. Third, safety management of medical engineering equipment for cardiac surgery must be strictly performed. Fourth, simulations of practical problems are necessary. People make mistakes, machines can fail, the electricity supply can be cut, consumables may be defective, or consumables may break. The higher the number of people involved, the more easily problems can occur due to the complexity of the system. Failures inevitably occur at a certain frequency. In other words, efforts can reduce the probability of a failure but cannot reduce it to zero. It is an empirical fact that the reliability of judgment and human responses become transiently impaired to a large degree during a state of panic. Extracorporeal technologists are required to be able to deal with such emergency situations without making errors or becoming flustered and must retain a sense of composure while working through a checklist and engaging in troubleshooting. This is a situation that demands a higher level of ability than is normally required, and this ability needs to be exercised in an intensive, timely, and precise manner. To properly acquire and maintain this ability, it is essential to undergo practical training that involves problem simulations. We must carry out simulations of problems based on this undeniable fact.