Impact of Using Cumulative SUM (CUSUM) Control Chart in Maternity Department on Mother and Infant Health: a Cluster Randomized Trial

1. RATIONAL Quality improvement has become a central tenet of health care. In obstetrics and gynaecology departments, each admission may affect the health of not one, but two individuals, making high quality of care particularly important. In addition, most women admitted for obstetric reasons are healthy individuals in whom the goal is full preservation of health.

Measurement plays an important part in improving quality of care and promoting beneficial changes. Therefore, over the last decade much effort has gone into developing and using measures of quality.

The first step towards measuring quality of care in obstetrical departments is to select quality indicators. Conventional quality indicators are severe events such as maternal death and neonatal death. However, advances in obstetrical management have made such events extremely rare, and other quality indicators must now be sought.

Once quality indicators are identified, the best means of monitoring them must be determined. The use of statistical methods to monitor and control a process, known as Statistical Process Control (SPC), seems particularly promising for monitoring quality indicators. SPC uses rigorous time-series analysis methods, whose results are reported as a graph of changes in outcome rates over time. Moreover, SPC can help to determine whether these changes are real (i.e., related to a causative factor) or merely a manifestation of natural variability. Among SPC tools, CUmulative SUM (CUSUM) charts are widely used for industrial quality control and have been found effective for measuring and monitoring healthcare outcomes.

In obstetrics, Cumulative Sum (CUSUM) charts have been used to monitor Apgar scores or the performance of sonographers in assessing nuchal translucency in the first trimester of pregnancy.