Patients who deteriorate without recognition or timely interventions are at risk of critical care admission and increased morbidity or mortality. This article outlines the systematic ABCDE (airway, breathing, circulation, disability, exposure) approach to patient assessment, which enables healthcare practitioners to identify and respond to life-threatening conditions in order of priority. The patient’s vital signs should be measured as part of the ABCDE assessment and recorded using a track and trigger tool to enhance recognition of physiological abnormalities that signal deterioration. To optimise communication and escalation of deteriorating patients, healthcare practitioners should report ABCDE assessment findings using a structured communication tool.