Resumen de Risk-adjusted cumulative sum charting procedure based on multiresponses

Xu Tang, Fah F. Gan, Lingyun Zhang

• The cumulative sum charting procedure is traditionally used in the manufacturing industry for monitoring the quality of products. Recently, it has been extended to monitoring surgical outcomes. Unlike a manufacturing process where the raw material is usually reasonably homogeneous, patients’ risks of surgical failure are usually different. It has been proposed in the literature that the binary outcomes from a surgical procedure be adjusted using the preoperative risk based on a likelihood-ratio scoring method. Such a crude classification of surgical outcome is naive. It is unreasonable to regard a patient who has a full recovery, the same quality outcome as another patient who survived but remained bed-ridden for life. For a patient who survives an operation, there can be many different grades of recovery. Thus, it makes sense to consider a risk-adjusted cumulative sum charting procedure based on more than two outcomes to better monitor surgical performance. In this article, we develop such a chart and study its performance.