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There was coincidence among the initial ultrasound diagnostic impression and after the clinical monitoring in 94.3% (CI: 95% 90.7-95%). There was no ultrasound diagnostic coincidence in 31 cases, of serious pathologies in two cases of carcinoma (of pancreas and urothelial), although both were referred to the corresponding specialist despite the absence of ultrasound findings in the initial examination. The main ultrasound types/groups not coinciding were the abdominal/abdominopelvic (13 cases, 41.9% of total non-coincidence), urological (6, 19.3%), and those of soft tissues (4, 13%). We only found a statistically significant association with taking more actions or diagnostic tests where there was no coincidence (8.8% of actions or tests in noncoincidence vs. 91.2% in coinciding cases) with respect to when it was not done (3.1% vs. 96.9%); p=0.005. And with referral to another specialist (87.6 vs. 12.4 according to whether or not there was coincidence), compared to not referring (96.0 vs. 4.0%); p<0.001.

Discussion

The results of the study offer important information mainly regarding the feasibility and utility of the POCUS carried out in PC practices. As for the feasibility, we considered the short time of realization, compatibility with the habitual visits and diversity of clinical scenarios where it was applied. Utility took into account the high percentage of initial diagnoses and diagnostic coincidence with the definitive diagnoses considering the next clinical course, and safety with the low percentage of false negatives and none of them with high clinical repercussion. On the other hand, its development clearly showed the difficulties in carrying out the study, even in providing continuity in healthcare practice in the performance of ultrasounds; which is another indication of its applicability.

The range of modalities of ultrasound scans performed has been very broad, with the abdomino-pelvic and urological, musculoskeletal and soft tissue scans being predominant; all together, these modalities have supposed 83.6% of the total. Only one cardiac scan was performed and no other more specific (mammary, supra-aortic trunks, etc.). This diversity of examinations coincides with what was found in other studies [13], although due to the scarce number of doctors participating in the pilot study, their probable lack of familiarity or skill in certain areas, and being circumscribed to a specific health system, results in discordant revisions that indicate frequent performance of other ultrasounds that in this study were not considered: obstetric, cardiac (only one case), breast, ophthalmological, vaginal or rectal echo-endoscopy, or in emergencies [1,13-16]. This backs the potential for a greater extension of the POCUS, as well as the types performed in this study, to other modalities and clinical scenarios.

The majority of the ultrasounds were done in a scheduled manner, although 27% were immediate in the healthcare visit, a proportion hardly examined in other studies of the area of the PC, although the high volume of examinations performed in the time and their proportion with respect to all the visits, as well as the short time that the POCUS takes (in our study even the abdominopelvic have a median of 13 minutes), leads to presupposing that a large part of them are feasible of being integrated in the spontaneous visit or on demand [15]. This is important because it backs the use of the ultrasound as another support tool in the usual visit. In other studies the duration of the examinations has been even shorter, even of five minutes [15]. Those of a shorter duration (soft tissues, musculoskeletal, pulmonary) and those that do not require previous preparation (for example, those not requiring fasting) are shown to be most suitable for these examinations integrated in an unscheduled consultation. In short, as some studies show, the POCUS becomes a habitual tool in the practices, with a use that can reach 8% of all of them [15].

As already commented, the examination time has been brief. Those that took longer have been the abdominal/abdominopelvic/ urological scans and the testicular/gynaecological scans; even so, both with a median of 13 minutes. Although the time of some studies has been less, one must consider that several of them refer to emergency or screening situations, with a specific and concise focus [2].

The high percentage of findings (65%) found in them endorse the utility of the POCUS, coinciding with other studies [15]. An association of findings has been found with the ultrasound modality, sex and age; as well as the high coincidence (94%) between the initial diagnostic ultrasound and the definitive one based on the later clinical monitoring. On the other hand, other studies show a high diagnostic correlation between the family doctor and the hospital specialist (93% of concordance) and with the radiologists (80-89%) [17].

It is shown to be a safe technique if we consider the fact of not finding diagnostic errors with clinical repercussions. There were only two cases of ultrasounds in which no findings were made and later serious diseases were diagnosed, specifically one of pancreas carcinoma and another of urothelial carcinoma. In both cases, despite not having any findings, other urgent diagnostic tests were requested (an abdominal CT scan that show the pancreas carcinoma) or the patient was sent to other specialists (referral to urology due for hematuria). In addition, significant association was found between taking more actions with there being no diagnostic coincidence in the diagnostic ultrasound. This also shows the integration of the POCUS in the corresponding clinical scenarios and their diagnostic reasoning and handling of uncertainty by the professionals faced with them, with a low proportion of false negatives as described in other studies, which is 5% [18]. In the study by Andersen et al. [15], the POCUS entailed a diagnostic change and the handling plan of half of the patients, in addition to reducing the referrals to the second and third care level also in this proportion; and in this same study aspects of uncertainty and diagnosis were assessed in the sense that the positive findings were classified with certainty (45.7%) and negative with certainty (32.3%), while the uncertain positives or negatives made up 19.5% [15]. The authors comment that the more specific the anatomical area to examine, and the more directed the ultrasound, the greater are the quality and certainty obtained [2].

Despite the musculoskeletal ultrasound and that of soft tissues being much performed modalities, diagnostic-therapeutic manoeuvres (drainage/infiltrations) were done on only 15 cases of the total of the 547 scans, much lower than that referred to in other studies where an ultrasound-guided procedure was done on a third of them [13], perhaps due to a need to acquire more skill in these practices.

The pilot study (qualitative research by survey and narration) examined other aspects related to the difficulties in carrying out the research study, results presented in unpublished congresses, where finally of the nine professionals, three did not carry out or did not provide their ultrasounds. Two referring to practice overload (unanimous reason, 9 out of 9, as the main barrier for the carrying out the study with all its potential and intensity) and lack of support by the organization (7 of 9), and another for instability of a place to work in centers without ultrasound. Another two professionals gathered or recorded a limited number of examinations, much less than those performed. Although this affected the strength of the study, it does reflect, as the pilot study that it is, the reality and obstacles for implanting and making routine a technique that on the other hand is shown to be feasible and useful in PC. And although with a limited number of the total ultrasounds, professionals and geographic location, it is probable that it reflects the reality of the application in other health systems.

It has delimited areas for improvement for the implementation of ultrasound in our organization, providing checklist-type records, focusing the consequent training activities, and indicating institutional aspects that must favor it. On the methodological base and results obtained, it shows that a broader study is pertinent, which also explores the satisfaction of professionals and patients, and compares the more prevalent or relevant scenarios with family doctors who do not perform ultrasound scans. It would also be interesting to carry out and compare the obtained results with other broader studies and in our area with other health systems.

Conclusions

The POCUS is shown to be feasible/compatible with the PC practice (considering duration and modalities), useful (for findings/diagnostic coincidence), safe (providing confidence in the diagnostic-handling and with low false negatives with clinical repercussions). The different care realities could limit the generalization of results, although it also reflects the versatility of the use of the POCUS; with the need to explore/broaden its potential applicability. The organizational aspects and overload of the PC practice can limit its extension.

Acknowledgements

Our thanks to the Department of Medicine of the University of the Basque Country (UPV/EHU) for its support in financing the project, to the Research Unit of the Basurto University Hospital for its support in the statistical analysis, and to the Bilbao-Basurto IHO for the translation of the article. Also, to the patients, who unanimously facilitated the handling of the examinations carried out.

Ethical Aspects

The patients received a Patient Information Sheet (PIS) and signed the Informed Consent (IC). The forms were duly coded to keep patient records and data analysis anonymous. The study had the approval of the Research Ethics Committee of Euskadi (CEIm-E), code PS2021046, August 3rd of 2021.

Conflict of Interest

None of the authors presents any conflict of interest. The research group belongs to the Osatzen Group (Basque Family and Community Medicine Society) on ultrasound. Two of the professionals, MAE and MGA, are part of the working group of the Sub-Directorate of PC in the strategy of implementing ultrasound in PC practice. None of the researchers are related to ultrasound companies or products, or receive remuneration for carrying out the study.

Funding

Department of Medicine of the UPV/EHU. Basque Healthcare Service (Osakidetza). Bizkaia, Spain. Ultrasound group of the Basque Society of Family and Community Medicine Osatzen – semFYC). Approval: CEIm-Euskadi (PS2021046).

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