Introduction. The increasing use of telephone medical advice requires the development of telemedicine tools to assess the patient's severity. Respiratory rate (RR) is a simple vital parameter and is often associated with morbidity and mortality of patients. There is no standardized measure of RR by telephone.

Objective: The investigators wanted to evaluate the RR measurement by phone using a smartphone application called RRate.

Methods. Adults who have been admitted for less than 6 hours to the emergency department after calling Center 15 and whose main reason for consultation is dyspnea will be included. Patients with non-invasive or tracheotomized ventilation will be excluded. The main objective will be to compare by Bland-Altman method the accuracy of the RRate measurement by phone to a one-minute RR measurement at patient's bedside. Secondary endpoints will evaluate the length of RR measurement according to the different methods used; measurement failure criteria; the accuracy of different measurement techniques (RRate at patient's bedside, impedancemetry, traditional measurement during 15s or 30s).

Expected Results. The accuracy of the RR measurement by RRate over the telephone should be within the limits of agreement. The measurement time should be shorter with the RRate application than with traditional methods. However, the measurement by telephone should not always be feasible in patients with mild dyspnea or with poorly audible breathing.

Inclusion Criteria:

• Age >18yo
• Dyspnea as main reason for consultation
• Regulated by "Centre 15"
• Admitted for less than 6hours at emergency department

Exclusion Criteria:

• Non invasive or tracheotomized ventilation
• Cognitive impairment
• Pregnancy

Every adult patient admitted to Grenoble University Hospital's emergency department whose main reason for consultation is dyspnea and who's been dispatched by "Centre 15"