As the focus of clinicians and government shifts from speciality-based care to system-based key performance indicators such as the National Emergency Access Target (NEAT) or the 4-h rule, integration between emergency department (ED) and inpatient clinical workflows and information systems is becoming increasingly necessary. Such system measures drive the implementation of integrated electronic medical records (ieMR) to digitally integrate these workflows. The objective of this case study was to describe the impact of digital transformation of the ED–in-patient interface (EDii) of a large tertiary hospital on process measures and clinical outcomes for patients requiring emergency admission to hospital. Data were collected from routine clinical and administrative information systems to measure process and clinical outcome measures, including ED length of stay, compliance with the 4-h rule and in-patient mortality between 28 November 2014 and 28 February 2017. The 4-h rule compliance for all patients, as well as for the EDii group (admitted to hospital excluding short stay ward), declined after digitisation. There were 55 fewer deaths in the postintervention group (15% relative reduction; P = 0.02) and a 10% relative reduction in adjusted mortality as measured by the Hospital Standardised Mortality Ratio for emergency patients (eHSMR), which did not reach statistical significance. Digital deceleration in ED performance did occur with an ieMR rollout, but worsening of key patient outcomes was not observed. What is known about this topic? Much has been written about the introduction of electronic medical records (EMRs) in emergency departments. This work sits alongside a substantial body of evidence outlining the relationship between process measures of ED performance and important patient outcomes. However, much less is known about the impact of digital transformation on the complex adaptive system that is the EDii and the impact of digitisation on the vulnerable group of patients who require emergency admission to hospital. What does this paper add? The objective of this case study was to describe the effect of a rapid rollout of an integrated EMR. This EMR simultaneously transformed care delivery both in the ED and the inpatient space and impacted on the politically and clinically sensitive performance and outcome measures of the EDii in a large tertiary hospital. The present study is the first that specifically examined the effect of digitisation at the EDii. What are the implications for practitioners? The understanding that digital deceleration will occur, but that with good patient outcome monitoring worsening of key patient outcomes is not likely to occur, now holds a key place in digital transformation planning. The measures of the EDii examined in this case study provide a foundation for this montoring.