Background: Acute dyspnoea is a common symptom in prehospital emergency medicine. As ultrasound gained in importance for diagnosis in patients with acute respiratory distress, it plays even a role in the prehospital setting. However, prehospital emergency ultrasound (PEU) remains challenging and requires knowledge and skills. New prehospital ultrasound devices offer the possibility for tele-supervision. The impact of tele-supervision of PEU in patients with acute dyspnoea is unclear.

Objective: This prospective observational study aims to evaluate the effect of PEU with tele-supervision on diagnosis, treatment strategies and cognitive load in comparison to PEU without tele-supervision in patients with acute dyspnoea.

Methods: In total 350 prehospital emergency patients with acute dyspnoea will be included in this study. Patients will be observed in two groups. In group 1 PEU will be performed with tele-supervision, whereas in group 2 PEU will be performed without tele-supervision (tele-supervision not available).

Inclusion Criteria:

Patients will be included, if they suffer from acute dyspnoea and at least one of the two following signs of respiratory failure:

• Respiratory rate >20 breaths per minute
• Peripheral oxygen saturation without oxygen supplementation <90%

Exclusion Criteria:

• under the age of 18
• if PEU will lead to a delay of live-saving treatment or transportation
• if patient rejects the PEU, the patient will be excluded

350 critically ill patients with acute dyspnoea will be included in this study. In 175 patients ultrasound with tele-supervision and in 175 patients ultrasound without tele-supervision will be performed. Allocation to one of the two groups depends on the availability of tele-supervision. Tele-supervision is available in 50% of the time.