Background: This article describes how the Pharmacy and Therapeutics Committee at Lutheran General Hospital (Park Ridge, IL) formed a continuous quality improvement (CQI) team and used statistical process control (SPC) tools to assess efforts to reduce medication errors.
Methods: The team worked with the nursing quality council to develop an intravenous (IV) training module for nurses that effectively decreased the average number of errors per month. The article illustrates the effective use of a run chart, a Pareto chart, and two types of control charts (p-charts and np-charts) to identify an opportunity for improvement, develop an improvement strategy, and measure the effectiveness of the intervention.
Conclusion: Lessons learned from this case include the following: 1) Although run charts can be used as a preliminary step to determine whether a process has common-cause or special-cause variation, p-charts or np-charts are more precise tools for identifying special causes and for measuring the impact of interventions; 2) Pareto charts are useful for focusing on the areas of a process that will have the greatest impact in achieving the desired results; 3) When p-charts show little variation in control limits from month to month, the np-chart is an appropriate and more user-friendly alternative; and 4) In addition to validating the overall effectiveness of the intervention, the np-chart also helped to identify where the intervention failed.