This study adds to the existing body of evidence on the feasibility of teleultrasound by demonstrating its successful implementation in the challenging environment of helicopter flight. The physicians produced images of good diagnostic quality in all nine flights. The disparity in image quality between the RUQ and LUQ, with the former exhibiting superior quality, is consistent with findings reported in previous research [13]. This could be due to the spleen’s smaller size and the complexity of LUQ imaging compared to the more straightforward liver-centered RUQ imaging [14].

Image ratings were generally lower from the second in-hospital radiologist compared to the remote expert. Absence of live interaction might have contributed to lower ratings from the former, while novelty bias could have led to inflated ratings from the remote expert. Nevertheless, the agreement on binary outcomes, such as clear imaging of the pleura, suggests all the images met basic requirements.

Our study, unlike conventional teleultrasound studies, involved practitioners with prior experience in emergency ultrasound, including eFAST. The questionnaire data indicates that they still would incorporate telementored eFAST into actual patient care. This suggests the method’s applicability beyond the scope of novice practitioners.

The combination of standardized terms, a slideshow presentation, and the physicians’ existing familiarity with eFAST appears to have prevented misunderstandings of ultrasound terminology. The absence of reported difficulties in understanding the remote expert supports the emphasis placed on the use of shared ultrasound terminology in previous studies [15] .

The duration of eFAST was significantly longer in the helicopter compared to the hospital setting. In their regular practice, the anesthesiologists mainly performed the cardiac, lung, and procedural ultrasound for vascular access, unlike eFAST, which is a more extensive evaluation of several regions. Their varying and limited experience with eFAST, along with the challenging environment in-flight, likely extended the duration of the procedure and contributed to the large standard deviation of 2:27 min.

The impact of geographical location on connection stability emerged as an important finding in our study, but the reasons for this phenomenon are not fully understood. In urban areas, there are numerous pedestrian-focused base stations. A fast-moving helicopter in this environment is susceptible to interference and will trigger frequent handovers between base stations. As per the user feedback, SINR and handover rates, the proximity to urban areas seemed to have a more detrimental effect on connection stability than the variations in altitudes of 500 and 1000 ft. This highlights the importance of considering geographical factors in the planning and execution of teleultrasound procedures during flight.

However, our data indicate that altitude levels still play a role in determining LTE coverage and connection stability. Higher altitudes were inversely correlated with signal quality, and an ascent to 2000 ft resulted in immediate loss of connection. Thus, altitude should also be considered for ensuring optimal connectivity for in-flight teleultrasound.

In The Norwegian Air Ambulance Service, helicopters generally operate within an altitude range of 0–10,000 ft above mean sea level, usually staying below 5000 ft above ground level. The selection of flight routes and altitudes is a complex decision-making process influenced by a myriad of factors including weather, topography, tactical, and medical considerations. Pilots have the discretion to alter pre-planned altitudes and routes, given that such changes are permissible by weather conditions, the landscape, and air traffic control. However, any modifications aimed at enhancing teleultrasound communication must be weighed against potential delays in patient care and loss of flight time.

Communication between the physician and the remote expert on the Voice over LTE network outperformed communication on the video conferencing software with LTE connection. The latter included multiple wireless links which could compromise the reliability of the communication. In Voice over LTE, data packets containing audio transmission are prioritized to ensure a stable audio link. Users reported greater satisfaction with dependable audio communication, emphasizing its indispensability in telementored ultrasound.

An unforeseen yet enlightening event took place during our study. On the same day as the telementored examinations, an anesthesiologist from the study performed eFAST on a severely injured patient during helicopter flight. He reported that the prior telementoring effectively prepared him for this real-life application. This incident corroborates studies that demonstrate the value of teleultrasound as an educational tool [16].

Although teleultrasound shows promise, it is crucial to note that the technology does not negate the need for skilled health care personnel. In fact, it introduces an additional layer of complexity by demanding support from a remote expert. While the feasibility of teleultrasound has been demonstrated in emergency medicine, its clinical benefit for patients has not been established [8].