Track-and-Trigger System: Identifying and Predicting Patient Deterioration through Scores and Algorithms

A track-and-trigger system (TTS) is a key component of the afferent limb of a rapid response system (RRS), alerting teams to deteriorating patients. Most TTSs identify deterioration through measurements of vital sign abnormalities (e.g. heart rate, oxygen saturations, temperature), but may incorporate additional criteria such as seizure or clinical concern. Traditional TTSs either alert on extreme values in one vital sign (e.g. tachycardia) or aggregate vital sign abnormalities into a composite early warning score (EWS). Both approaches have the advantage of simple implementation and provide a common language in which to communicate patient risk in clinical environments. However, this simplicity comes at the expense of high numbers of false alerts, generating unnecessary demand on limited RRS resources. Evidence that TTSs improve patients’ outcomes in hospital is limited. In this chapter, we will summarise TTSs used internationally and the development of more sophisticated TTSs to improve early detection of patient deterioration.