Monitoring intensive care unit performance using statistical quality control charts.

This paper discusses results of a study in which mortality rates and APACHE II severity of illness scores of Intensive Care Unit (ICU) patients were monitored for a five-year period (1986-1990) using statistical quality control charts. The purpose of the study was to determine whether severity of illness of patients and mortality rates had changed significantly over this time horizon. The results show that the Intensive Care Unit process is stable and in statistical control. There is no apparent trend in the severity of illness scores nor mortality rates measured both at ten days and six months from the last ICU admission. Quality control charts, which have been used extensively to detect changes in industrial processes on a short term basis, provide a simple method of monitoring the ICU process over an extended time horizon.