Quality control techniques in surgery: Application of cumulative sum (CUSUM) charts.

Cumulative sum graphs are quality control charts that are possibly the most frequently used for monitoring clinical-care processes. One of their main advantages is the use in rare cases and in events with low incidence, where it would be necessary to obtain a large sample and a long follow-up time with conventional statistical methods, which is impossible in certain cases. This is also why they are useful for studying learning curves, the introduction of new technologies and, in general, for assessing the quality of care outcomes themselves, because their profile is sensitive to very subtle changes in trends (positive or negative), which would not be observed with other methods. On the other hand, their use can be expanded beyond quality control or monitoring, which is a new aspect in clinical research.