Improved implementation of the risk-adjusted Bernoulli CUSUM chart to monitor surgical outcome quality.

METHODOLOGY ISSUE: The traditional implementation of the risk-adjusted Bernoulli cumulative sum (CUSUM) chart for monitoring surgical outcome quality requires waiting a pre-specified period of time after surgery before incorporating patient outcome information. PROPOSED SOLUTION: We propose a simple but powerful implementation of the risk-adjusted Bernoulli CUSUM chart that incorporates outcome information as soon as it is available, rather than waiting a pre-specified period of time after surgery. EVALUATION: A simulation study is presented that compares the performance of the traditional implementation of the risk-adjusted Bernoulli CUSUM chart to our improved implementation. We show that incorporating patient outcome information as soon as it is available leads to quicker detection of process deterioration. ADVICE TO PRACTITIONERS: Deterioration of surgical performance could be detected much sooner using our proposed implementation, which could lead to the earlier identification of problems.