Mental health emergencies attended by ambulances in the United Kingdom and the implications for health service delivery: A cross-sectional study.

Objective: In the context of increasing demand for ambulance services, emergency mental health cases are among the most difficult for ambulance clinicians to attend, partly because the cases often involve referring patients to other services. We describe the characteristics of mental health emergencies in the East Midlands region of the United Kingdom. We explore the association between 999 (i.e. emergency) call records, the clinical impressions of ambulance clinicians attending emergencies and the outcomes of ambulance attendance. We consider the implications of our results for optimizing patient care and ambulance service delivery.

Methods: We conducted a retrospective observational study of records of all patients experiencing mental health emergencies attended by ambulances between 1 January 2018 and 31 July 2020. The records comprised details of 103,801 '999' calls (Dispatch), the preliminary diagnoses by ambulance clinicians on-scene (Primary Clinical Impression) and the outcomes of ambulance attendance for patients (Outcome).

Results: A multinomial regression analysis found that model fit with Outcome data was improved with the addition of Dispatch and Primary Clinical Impression categories compared to the fit for the model containing only the intercept and Outcome categories (Chi-square = 18,357.56, df = 180, p < 0.01). Dispatch was a poor predictor of Primary Clinical impression. The most common predictors of Outcome care pathways other than 'Treated and transported' were records of respiratory conditions at Dispatch and anxiety reported by clinicians on-scene.

Conclusions: Drawing on the expertise of mental health specialists may help '999' dispatchers distinguish between physical and mental health emergencies and refer patients to appropriate services earlier in the response cycle. Further investigation is needed to determine if training Dispatch operatives for early triage and referral can be appropriately managed without compromising patient safety.