Background: Recognition and response of deteriorating patients is fundamental to safe, high quality healthcare. Failure to recognise and respond to deteriorating patients is associated with serious adverse events, both during and after emergency department care. This study aims to determine if the implementation of HIRAID (History, Identify Red flags, Assessment, Interventions, Diagnostics, communication and reassessment), an emergency nursing framework, improves patient safety.Methods: This quasi-experimental cohort study was conducted between November 2017 and February 2019 in two regional hospitals in [Anonymised], Australia. HIRAID was implemented using a multi-pronged behaviour change intervention. Data of 920 patients (374 pre-cohort and 546 post-cohort) who had an episode of deterioration within 72 hours of emergency department departure were collected. Statistical tests were conducted as two-sided, with a 95% confidence interval to determine pre/post cohort association. The StaRI checklist was used in reporting this study.Results: Patients in the post group were older with more comorbidities, but experienced fewer episodes of clinical deterioration associated with care delivered in the emergency department (27% to 13%). There was a reduction in treatment delays [pre n=28 (28.3%) versus post n=11 (15.1%), p=0.041, 95% CI (1.1%–25.3%)], and delay or failure to escalate care when abnormal vital signs were identified [pre n=20 (20.2%) versus post n=5 (6.9%), p=0.014, 95% CI (3.5%–23.1%)]. The proportion of isolated nursing-related causal factors decreased from 20 (21%) to 6 (8%). Conclusions: HIRAID is a standardised emergency nursing framework which provides a structured, evidence-based approach to emergency nursing assessment that could be adapted for a variety of clinical settings. Implementing HIRAID using the principles of behavior change is associated with a reduction in clinical deterioration related to emergency care.