Monitoring the evolutionary process of quality: Risk-adjusted charting to track outcomes in intensive care

Objective: To present graphical procedures for prospectively monitoring outcomes in the intensive care unit. Design: Observational study: risk-adjusted control chart analysis of a case series. Setting. Tertiary referral adult intensive care unit: Princess Alexandra Hospital, Brisbane, Australia. Patients: A total of 3398 intensive care unit admissions from January 1, 1995, to January 1, 1998. Conclusions. Risk-adjusted process control charting procedures for continuous monitoring of intensive care unit outcomes are proposed as quality management tools. A modified Shewhart p chart and cumulative sum process control chart, using the Acute Physiology and Chronic Health Evaluation III model mortality prediction for risk adjustment, are presented. The risk-adjusted p chart summarizes performance at arbitrary intervals and plots observed against predicted mortality rate to detect large changes in risk-adjusted mortality. The risk-adjusted cumulative sum procedure is a likelihood-based scoring method that adjusts for estimated risk of death, accumulating evidence from outcomes of all previous patients. It formally tests the hypothesis of a change in the odds of death. In this application, we detected a decrease from above to predicted risk-adjusted mortality. This was temporally related to increased senior staffing levels and enhanced ongoing multidisciplinary review of practice, quality improvement, and educational activities. Formulas and analyses are provided as appendices.