Point-of-Care Ultrasound (POCUS) Practices in the Helicopter Emergency Medical Services in Europe

Background: The extent to which Point-of-care of ultrasound (POCUS) is used in different European helicopter EMS (HEMS) is unknown. We aimed to study the availability, perception, and future aspects of POCUS in the European HEMS. Methods: A survey about the use of POCUS in HEMS was conducted by a multinational steering expert committee and was carried out from November 30, 2020 to December 30, 2020 via an online web portal. Invitations for participation were sent via email to the medical directors of the European HEMS organizations including two reminders. Results: During the study period, 69 participants from 25 countries and 41 different HEMS providers took part in the survey. 96% (n=66) completed the survey. POCUS was available in 75% of the responding HEMS organizations when needed (56% always, and 19% occasionally). 17% were planning to establish POCUS in the near future. Responders who provided POCUS used it in approximately 15% of the patients. Participants thought that POCUS is important in both trauma and non-trauma-patients (73%, n=46). The extended focused assessment sonography for trauma (eFAST) protocol (77%) was the most common used protocol. A POCUS credentialing process including documented examinations was requested in less than one third of the HEMS organizations. Conclusions: The majority of the HEMS organizations in Europe are able to provide different POCUS protocols in their services. The most used POCUS protocols were eFAST, FATE and RUSH. Despite the enthusiasm for POCUS, comprehensive training and clear credentialing processes are lacking in about two thirds of the European HEMS organizations.

study the availability, perception, and future aspects of POCUS in the European HEMS using an online survey.

Methods
A multinational steering expert committee developed a questionnaire about the use of POCUS in HEMS. The ten-minutes survey consisted of 24 questions regarding demographics, availability, present and future use of POCUS in HEMS, importance of POCUS in different conditions, used POCUS protocols, and if there were any necessary credentialing POCUS processes for medical providers (Suppl Table 1). The survey was provided online via the web portal SurveyMonkey®. To ensure that every participant could only answer the survey once, the IP-address was recorded, whereas all data were analyzed anonymously. The invitation link and the QR-code for the survey was sent via email to the medical directors of the European HEMS organizations of 28 countries across Europe and a second and third reminders were sent to nonrespondents. The survey was available online from November 30 to December 30, 2020 and it was possible to answer it with any mobile device (smartphone, tablet) or PC.
Descriptive analysis was done using the analysis tools provided by SurveyMonkey® and the statistic software GraphPad Prism 9.0 (GraphPad Software, San Diego, CA, USA). Data were presented as median (range) and mean (SD) for ordinal and continuous data, and number (%) for categorical data. If data were missing, valid percentages were calculated from the available data. The study is in line with the current European general data protection regulation (GDPR).

General Data
During the study period, 69 participants from 25 countries (89% of the invited countries) and 41 different HEMS organizations took part in the survey. The survey was completed by 96% (n=66 of 69) of the participants. Most of the participants 95.5% (n=65 of 69) were males, between 41 and 50 years old, and had a leading position within their HEMS organization (71%, n=49 of 69). Almost all HEMS programs (97.5%, n=40 of 41) were physician staffed, in which the physician was joined by a paramedic in 65% (n=26 of 40) or a ight nurse in 20% (n=8 of 40) ( Table 1). An In rmier Siamu (Infermier -French term for a nurse; Siamu -abbreviation for the French term "Soins Intensifs et Aide Medicale Urgente"; intensive care and urgent medical aid) a nurse that combines clinical intensive care medicine and preclinical emergency medicine, were part of the medical team in 7.5% (n=3 of 40), and a paramedic or ight nurse in 2.5% (n=1 of 40) respectively (missing data were in 5%, n=2). The non-physician staffed HEMS was only paramedic service.

POCUS and HEMS organizations
Unrestricted availability of POCUS was in 56% (n=23 of 41) of the HEMS organizations (standardized equipment at all related HEMS bases), occasionally possible in 19.5% (n=8 of 41), and not possible in 24.5% (n=10 of 41) ( Table 1). The time since POCUS had been established in the different HEMS organizations ranged from less than one year up to 20 years. Of the HEMS organizations not yet providing POCUS, 70% (n=7 of 10) stated planning to integrate it in the future within a median (range) time of 2 (1 -4) years. Responders of the HEMS providers in which POCUS was available estimated that POCUS had been used in a median (range) percentage of 15% (0.8 -37.5) of patients (Table 2).
Regarding the credentialing process for using POCUS in the different HEMS organizations providing POCUS, 35% (n=11 of 31) has an established credentialing process. If a credentialing process was established, a POCUS-course led by an expert was requested in 9 HEMS, an additional didactic teaching of an average of 6.5 hours and hands-on training of an average of 5.5 hours were requested in four HEMS. In two of the four mentioned HEMS organizations, documented POCUS cases were needed before using POCUS in HEMS. In the other two HEMS organizations, own didactic teaching and hands-on training were requested. Generally, comprehensive training and credentialing activities are scarce in the European HEMS organizations. Table 3 summarizes the results of the importance of POCUS in general, in different areas and different patient conditions. Most participants think that POCUS is important in both trauma and non-trauma patients (73%, n=46 of 63), whereas 19% (n=12 of 63) think that POCUS is more important in trauma patients, while 8% (n=5 of 63) think that it was important in non-trauma patients. Standard examination protocols are being used by the majority of participants 63% (n=38 of 60), whereas 32% (n=19 of 60) do not use such protocols and 5% (n=3 of 60) were not sure. The (e)FAST protocol is the most used protocol (77%). The ndings of POCUS were recorded in a reliable way (video clip or electronic database) in less than 30%, and mainly put down in writing on the mission protocols (Table 4).

POCUS devices
The most commonly used portable ultrasonography devices were, GE healthcare V-scan in 40% (n=21), FUJIFILM Sonosite iviz in 36% (n=19), Philips healthcare Lumify and Butter y Network iQ in 6% (n=3) respectively. Some HEMS organizations use more than one POCUS device manufacturer. Most of the participants (71%, n=39) were pleased with the devices used.

Discussion
Our study indicates that more than two-thirds of the European HEMS organizations provide POCUS in their helicopters and that a considerable number is planning to establish it soon. HEMS providers appreciate the increased need for POCUS integration in pre-hospital care. To our knowledge, this is the rst survey regarding the pre-hospital use of POCUS in HEMS organizations across Europe.
Data suggest that POCUS is feasible and useful in HEMS. Nevertheless, the evidence regarding improving direct patient outcome is weak and needs to be clari ed by properly designed prospective studies [10,11,[13][14][15][16][17][18]. There are different POCUS protocols that can be used in the pre-hospital setting which include extended (e)FAST to search for intraperitoneal uid, peri-cardiac uid, haemothorax and pneumothorax, [19,20], Rapid Ultrasound for Shock (RUSH) to de ne the cause of the shock, and Focused Assessment Transthoracic Echocardigraphy (FATE) to quickly evaluate the cardiac function [21][22][23][24]. Our results show, that (e)FAST is the most used protocol in HEMS.
With advancements in technology and training, the use of POCUS extended to more indications like diagnosis of eye injuries and bone fractures [25,26]. POCUS training should be tailored towards the speci c needs of the HEMS staff. The operators should be familiar with their own ultrasound machines and should be particularly knowledgeable of the sonographic artefacts that can mislead them [4,27].
The participants thought that POCUS examinations of the chest, abdomen and heart are very important, vascular access are important, while POCUS for airway management and regional anesthesia is less important, (see Table 3). It is of interest to note that the needed POCUS skills for airway management and interventions are more advanced. Currently less than one-third of the participating HEMS organizations seems to have a credentialing process for using POCUS. The other two-third assumed that the HEMS crews can perform POCUS. Training must be standardized to maximize the bene t of POCUS. European HEMS organizations should agree on common POCUS curriculum with an accepted standard that suits their needs. Competency is a key factor in successful clinical applications [4,28]. Using a Delphi methodology, Micheller et al. de ned a total of ve modalities (cardiac, thoracic, FAST, aorta, and procedural), with 32 measured competencies and 72 sub competencies [29] as the basis for the needed curriculum. Consecutive quality assurance and governance are probably more challenging, as POCUS ndings are interpreted in a dynamic clinical context. POCUS seems to be accepted and available in Europe. Besides the more frequent use of POCUS compared with North America, the survey underlines that HEMS in Europe is mainly physician staffed which can explain the frequent use of POCUS (9,28). Some participants stated that POCUS is used in more than 30% of their patients indicating proper training in a wide range of applications.

Limitations
The represented study has some limitations which we would like to highlight. First, it was a voluntary online survey that carries the risk of selection bias of participants who encourage the use of POCUS. This may overestimate the value of POCUS. Second, the majority of participants are leaders in their HEMS organization, with the risk of reporting results that are preferred by them and may be different from those who use it. Third, we did not get the response of all invited HEMS organizations carrying the risk of selection bias. The survey was asked in a limited period of 30 days possibly explaining the small sample size. Fourth, female responders were few with the majority being males. Finally, some of the participating countries and HEMS organizations were overrepresented. This was taken into consideration when reporting availability of POCUS in the organizations but could have skewed the opinion data.

Conclusions
Our study has shown that most of the HEMS organizations in Europe are able to provide different POCUS protocols in their services. The most commonly used POCUS protocols were (e)FAST, FATE and RUSH. The study is in line with the current European general data protection regulation (GDPR).
Consent for publication: Not applicable.
Availability of supporting data: The dataset generated and analysed during the current study are not publicly available due the ownership of the different air ambulance providers but are available from the corresponding author on request.
Competing interests: The authors declare that they have no competing interests.      14.6% (10) Table 3. Importance of POCUS in general, in different areas and different patient conditions