Interstitial lung diseases (ILD) comprise a group of diseases that share clinical, functional, and imaging manifestations, in which there is an inflammatory-fibrotic abnormality in the alveolar-interstitial structures. ILD can be classified as idiopathic and associated with pulmonary toxicants or other diseases, including systemic autoimmune diseases (SAD). ILD can affect a high percentage of patients with SAD such as antineutrophil cytoplasmic antibody-associated vasculitis, IgG4-related disease, and connective tissue diseases such as rheumatoid arthritis, systemic sclerosis, inflammatory myopathies, primary Sjögren’s syndrome, systemic lupus erythematosus or mixed connective tissue disease, in which it is one of the most important determinants of impaired quality of life and increased morbidity and mortality1,2. However, the greater availability of a much broader panel for detecting autoantibodies from immunology laboratories has made it possible to improve screening for autoimmune-derived ILD in patients with single organ disease, therefore some international societies recommend that rheumatologists and pulmonologists should collaborate in the diagnostic approach to these patients3. In this regard, an increasing number of national and international centres with interstitial lung disease units that undertake multidisciplinary work include rheumatologists as part of their teams4.

It is important to diagnose ILD early to initiate the most appropriate treatment in the early stages of irreversible structural lung damage. Functional tests are essential to detect and follow-up the disease, and DLCO (diffusing capacity of the lungs for carbon monoxide) is the measure that is affected the earliest in this type of disease5. However, low DLCO may also be due to other prevalent pulmonary diseases, such as emphysema in smokers, or the vascular involvement that accompanies some SAD such as systemic sclerosis or inflammatory myopathies, which require an imaging test. Chest X-ray has limited specificity and sensitivity and, although in suspected cases it can have a diagnostic accuracy of up to 80%6, a normal image does not exclude the diagnosis, and therefore it is mainly used to rule out other diseases associated with dyspnoea, such as infections, tumours or left heart failure7. High-resolution computed tomography (HRCT) is considered the gold standard for early and subclinical diagnosis, disease activity assessment and treatment monitoring of ILD8,9, but its use is limited by its relatively high cost and patient exposure to radiation.

Lung ultrasound (LUS) has recently emerged as a non-invasive, accessible and relatively inexpensive imaging technique that can detect lung conditions such as effusion and other pleural abnormalities, parenchymal lung consolidation and alveolar-interstitial changes of various aetiologies, including those present in ILD10–15. In numerous studies, LUS has shown high sensitivity and good concordance with HRCT in detecting and quantifying early or established lung involvement16–25. The high negative predictive value demonstrated by LUS suggests the technique could be used in the diagnosis of subclinical or early stages of ILD, as well as its consistence with HRCT, which means the latter could be spared in the follow-up and evaluation of pulmonary therapeutic response, along with clinical manifestations and respiratory functional study.

These promising applications of LUS in ILD as an efficient clinical tool currently require its learning system and technical use (appropriate equipment, scanning method and quantification of lung abnormalities) to be widely standardised so that they can be fully integrated into clinical practice and research in these diseases. There is no structured method of education and training in LUS, particularly in ILD, and very few recommendations for competency assessment and accreditation of its use in clinical practice26–28. As a first step to promote safe, appropriate, and quality use of LUS in ILD, we need to determine the current situation regarding the training and use of the procedure in our medical community.

The aim of our study was to determine education and training in LUS and its use in clinical practice and in the investigation of ILD among Spanish rheumatologists and pulmonologists.

The ILD that occur in SAD constitute a point where care and research between Pneumology and Rheumatology meet, in which LUS could play a relevant role as an imaging tool to complement the current diagnostic, therapeutic and research approach. The reliable and efficient use of any ultrasound modality depends on the skill and experience of the examiner; therefore, the standardisation and quality of its learning and use is extremely important. Currently, training in LUS for rheumatologists and pulmonologists may be included under general specialty training in some centres in Spain and abroad, but it is not standardised and lacks competency assessment and quality certification26.

This study, based on a survey among members of the ILD division of the SER and the SEPAR, is a preliminary snapshot of the current scenario regarding use and training in LUS in both specialties and, particularly, in Spanish ILD units. Although the number of respondents was not high as a percentage of SER and SEPAR ILD division members, it does indicate a sufficiently high level of interest and motivation among Spanish rheumatologists and pulmonologists of a wide age range in the emerging field of LUS.

As might be expected, slightly more than half the survey respondents were involved in ILD units in their centres, which certainly encouraged them to collaborate in the survey. It should be noted, however, that a considerable percentage of respondents who were not involved in these multidisciplinary units also actively participated in the survey. Furthermore, the survey clearly shows how LUS is still poorly established in clinical practice and research in both specialties, particularly in the field of ILD.

Our survey showed the diversity of the current LUS training methods but showed a strong majority opinion in favour of standardising and structuring LUS training programmes, combining formal theoretical and practical training in courses and supervised practice in the clinical setting and including a competency assessment. It is very likely that the sponsoring role of Scientific Societies as providers of LUS training will soon be very welcome.

LUS is an emerging clinical and research tool, particularly in the synergistic setting of pulmonologists and rheumatologists who manage ILD. There is currently a lack of structured LUS training and therefore an opportunity to develop high-quality training programmes to encourage optimal use of this imaging modality in this field.

No funding was received for this study

Fredeswinda Romero-Bueno has no conflict of interests to declare.

María Jesús Rodríguez-Nieto has no conflict of interests to declare.

Esperanza Naredo: Consultancy on lung ultrasound training for Bristol Myers Squibb.