Dyspnea is the subjective sensation of difficult or uncomfortable breathing. It accounts for approximately 10% of emergency department visits and 8% of calls to Emergency Medical Communication Centers. Nearly half of patients presenting with dyspnea require hospital admission, 15% require ventilatory support, and approximately 5% die. Early recognition of signs of respiratory severity is therefore essential to accurately assess clinical urgency, guide diagnostic evaluation, and inform appropriate management decisions.

In France, patients are encouraged to contact an Emergency Medical Communication Centers before presenting to an emergency department. Calls are managed by an emergency physician responsible for medical regulation, who performs a remote clinical assessment and determines the most appropriate level of care. Depending on the clinical evaluation, the physician may provide medical advice, refer the patient to an emergency department, dispatch emergency medical services, or send a physician-staffed mobile intensive care unit for life-threatening emergencies.

The remote assessment of patients presenting with dyspnea is particularly challenging. The inability to directly observe or examine the patient, combined with the caller's difficulty in accurately describing the clinical situation, may impair the recognition of disease severity and result in inappropriate triage decisions, including under-triage and over-triage :

Under-triage, characterized by failure to dispatch appropriate emergency resources or to refer the patient to an emergency department when indicated, may delay treatment and increase the risk of adverse outcomes, including mortality.

Conversely, over-triage, defined as unnecessary referral to primary care or emergency departments or inappropriate dispatch of emergency resources, contributes to emergency department overcrowding, inefficient use of prehospital resources, and increased healthcare costs.

In a previous study, we demonstrated that video-assisted medical triage improved emergency physicians' ability to assess the severity of patients presenting with acute dyspnea. This telemedicine tool enables real-time transmission of a live video stream from the caller's smartphone camera to the emergency physician through a secure digital platform, providing direct visualization of the patient's clinical condition. By enhancing remote clinical assessment, video-assisted triage has the potential to reduce both under-triage and over-triage.

In the present stepped-wedge cluster randomized trial, we hypothesized that incorporating real-time video support into the medical regulation of adult patients contacting an Emergency Medical Communication Centers for acute dyspnea would improve the quality of medical decision-making compared with standard telephone triage alone.