Prehospital ultrasound in emergency medicine: incidence, feasibility, indications and diagnoses

Sonography is an established diagnostic procedure in hospitals, but is not routinely used in prehospital emergency medicine. Several studies have addressed the use of ultrasound during helicopter flights and in emergency rooms, few in prehospital settings, but most focused on abdominal blunt trauma. Several case reports describe crucial decisions distinguished by ultrasound.

In this study, four different handheld ultrasound systems in 4 helicopters and one emergency vehicle were used over a cumulative period of 3 years. Incidence, feasibility, indication, diagnoses and exploration time (in subgroups) were investigated in an overall profile of emergency patients, encompassing the area of internal medicine.

On 971 missions ultrasound systems were available. In 17% of the cases ultrasound was considered valuable, in 144 patients (14.8%) sonographic studies were performed. Additional information could be given in 130 cases (90%). Compared with the available clinical data (return rate of 76%) there were no false-positive findings during this study, resulting in a specificity and positive predictive value of 100%, showing this technique to be reliable. Sensitivity was 85%, accuracy was 96% and negative predictive value was 95%.

Ultrasound is the only imaging modality and a useful diagnostic tool in prehospital emergency medicine. Helpful information can be provided in at least one of six cases (or even more) in a trauma-dominated collective. Examination time is short; it will not significantly delay medical care. Ultrasound examination could improve triage in cases of more than one patient in disaster medicine, but further studies are necessary.