Keywords Chest - Education, Training, Quality Assurance - Point of care
Introduction
Thoracic ultrasound (TUS) is used to visualize pathologies and provide clinical information
about the chest wall, parietal pleura, pleural cavities, visceral pleura, lung tissue,
diaphragm, upper and anterior mediastinal compartments, as well as related anatomical
structures [1 ]
[2 ]. The increased availability and mobility of ultrasound systems and rapidly growing
evidence has made TUS a first-line imaging modality in many different specialties
(e.g., respiratory medicine, emergency medicine, radiology, intensive care and anesthesiology)
and clinical settings (e.g., prehospital, emergency room, hospital ward, operating
theater, intensive care unit, outpatient clinic). TUS is especially useful when applied
in a focused manner to answer clinically relevant dichotomous (yes/no) questions as
part of a point-of-care ultrasound examination (POCUS) [3 ]
[4 ]. Low costs, bedside implementation, and the lack of radiation exposure mean that
TUS can be repeated as often as required. In recent years, TUS has also been increasingly
used with more advanced ultrasound modalities (e.g. contrast-enhanced ultrasound (CEUS))
and advanced ultrasound-guided interventions and monitoring have been developed and
implemented, especially within the field of respiratory medicine [1 ]
[2 ]
[5 ]
[6 ]
[7 ]
[8 ]
[9 ]
[10 ]
[11 ]
[12 ]
[13 ]
[14 ]
[15 ]
[16 ]
[17 ]
[18 ]
[19 ].
The increased use of clinical TUS has been proven to improve patient care and outcome
[15 ]
[20 ]
[21 ]. However, TUS can be a complex and operator-dependent technique, requiring sufficient
competency to allow both diagnostic ultrasound and ultrasound-guided interventions
to be performed safely [22 ]
[23 ]. In this paper we have considered TUS and other forms of chest imaging (e.g., chest
X-ray (CXR), computed tomography (CT)) as methods that supplement each other. Local
guidelines and availability will help the clinician to decide which method will be
of most benefit to the patient.
This position paper of the European Federation of Societies for Ultrasound in Medicine
and Biology (EFSUMB) describes the training requirements for TUS in Europe. A group
of specialists in ultrasound and thoracic ultrasound from across Europe including
specialists in respiratory medicine, radiology, intensive care, anesthesiology, surgery,
and internal medicine were invited to participate. A preliminary version was drafted
by CBL and CE and circulated among the other authors. All comments and changes were
incorporated in one document which was again circulated together with an accompanying
letter stating the specific points where there were discrepancies among the experts.
After the second round, only minor flaws remained that were checked by CBL and CE
and re-circulated for consensus. The final version of the Position Paper has been
approved by all members of the authors group and finally by the EFSUMB Executive Bureau. In
recently published position papers, the EFSUMB has described general professional
standards for medical ultrasound, advanced ultrasound techniques, ultrasound-guided
interventions, and CEUS. The training recommendations presented here are based on
EFSUMB’s fundamental statements [24 ]
[25 ]
[26 ]
[27 ]
[28 ]. The training recommendations will follow the general principles of three competency
levels for the practice of medical ultrasound used by EFSUMB and the Royal College
of Radiologists and are aligned with the European Respiratory Society’s certified
training program in TUS regarding content [29 ]
[30 ]. The rapid expansion, clinical implementation, and training with respect to TUS
as part of PoCUS have led to significant overlaps between the more classic three competency
levels and TUS performed with a PoCUS approach ([Fig. 1 ]). TUS performed as part of PoCUS has, therefore, not been specified in this document,
since it may involve aspects from different TUS levels as well as other types of ultrasound.
Fig. 1 Thoracic ultrasound competency levels.
Throughout the document the following terminology applies:
PoCUS: PoCUS approach to TUS.
TUS Level 1: involves the knowledge and skills needed to perform essential diagnostic
TUS examinations and basic TUS-guided interventions independently.
TUS Level 2: defines the knowledge and skills needed to perform more advanced real-time
TUS-guided interventions and diagnostic examinations.
TUS Level 3: involves training and practice on a more advanced level and requires
additional knowledge of advanced ultrasound technologies and engagement in education
and research.
Traditionally, the use of ultrasound-guided procedures has been considered EFSUMB
level 2 by default. Ultrasound-guided diagnostic pleural puncture and ultrasound-guided
pleural catheter insertion (i.e., real-time use of ultrasound to guide the needle
or catheter) are, however, essential skills for any physician performing TUS level
1, since the finding of a pleural effusion may directly result in the immediate need
for these interventions. Therefore, we have decided to consider these interventions
as basic TUS-guided interventions and include them in competency level 1.
In the previously published EFSUMB training recommendations for TUS, the recommendations
included the use of ultrasound when combined with endoscopic procedures [31 ]. Since then, the theoretical knowledge, clinical use, and required competencies
of both “transthoracic” TUS and “endoscopic” TUS have expanded significantly and training
and mentoring programs have now been subdivided into two separate categories. In order
to reflect this division, we have decided to include only transthoracic ultrasound
in this recommendation. Another important difference with regard to the previous TUS
recommendation is a shift from a predefined minimum number of examinations as an indicator
of competency to competency-based education where valid assessments are used to determine
competency [22 ]
[32 ]
[33 ].
A systematic approach, a good and thorough technique, effective reporting including
documentation of images, and clinical integration of TUS findings into the given
clinical context are mandatory for patient safety. TUS operators must acknowledge
their limitations and decide when to ask for help from more experienced colleagues,
or to consider other imaging modalities. All these aspects should, therefore, be included
in TUS training. For each EFSUMB level, we will outline the required theoretical knowledge,
detailed competencies, training, and assessment of TUS competency.
TUS – level 1
Necessary theoretical knowledge
Ultrasound physics, techniques, and clinical integration
Knowledge and understanding of:
Basic ultrasound physics
The generation of ultrasound images
Types of transducers, their particular imaging characteristics, and their use
Basic ultrasound controls (e.g., presets, gain, depth, focus, frequency)
B-mode, M-mode, and Doppler ultrasound
Common artifacts, including their physical fundamentals and specific role in TUS
Technical applications for artifact suppression (e.g., Tissue Harmonic Imaging and
Compounding) and their impact on the visualization of artifacts diagnostically relevant
for TUS
The indications for TUS
The integration of TUS findings into the clinical context in accordance with relevant
local, national, or international clinical practice guidelines
The strengths, weaknesses, and limitations of TUS
The advantages/disadvantages and risks of TUS and TUS-guided interventional techniques
in comparison to alternative diagnostic and interventional tools (including safety
aspects)
Knowledge of normal ultrasound anatomy of the chest and related structures
Detailed knowledge of the ultrasound anatomy of the chest wall, parietal pleura, pleural
cavity, visceral pleura, lung tissue, and diaphragm and basic knowledge of the ultrasound
anatomy of the mediastinum (upper/prevascular compartments).
Knowledge of the ultrasound patterns and signs seen in common pathologies in the thorax
and related structures and relevant pitfalls
Chest wall:
Fractures (e.g., rib, sternum, clavicle)
Subcutaneous emphysema, edema, hematoma, and inflammatory infiltration
Intercostal and accessory muscle respiratory effort
Signs of possible malignancy (e.g., focal lesions, signs of direct invasive growth)
Foreign bodies (e.g., catheters and drains)
Diagnosis of benign processes such as lipomas
Parietal pleura and pleural cavities:
Parietal pleural thickening, nodularity, and other findings (e.g., calcification)
Pleural adhesions
Pleural effusion incl. semiquantitative assessment of size, fluid characteristics
such as septation/loculation, and signs indicating the cause of the effusion (e.g.,
pleural metastases/ carcinosis)
Pneumothorax incl. semiquantitative assessment of size
Visceral pleura and lungs:
B-lines either present as focal pattern or “interstitial syndrome”
Thickened and/or fragmented visceral pleura line and artifacts associated with pathologies
of the visceral pleura and subpleural lung (comet tail artifacts)
Common lung parenchymal pathologies causing a “lung consolidation” pattern (e.g.,
infectious pneumonia, pulmonary embolism, obstruction atelectasis, compression atelectasis,
contusion, malignancy) and the corresponding ultrasound patterns seen in typical cases
Diaphragm:
Abnormal shape, herniation, tumors or nodular change on the diaphragm
Abnormal movement of the diaphragm
Competencies to be acquired
Preparation and ability to select and use the correct equipment
Ability to choose the optimal patient positioning for a given clinical context
Ability to decide if the available US system is sufficient for the application (for
instance handheld devices should not be used for advanced TUS)
Ability to choose the optimal transducer and presets to optimize an image (e.g., using
gain, depth, focus, frequency, image optimization software).
Ability to perform measurements and to insert pictograms/annotations
Ability to perform supplementary Doppler ultrasound for large vessel identification
Ability to recognize important anatomical landmarks on the thorax and related anatomical
structures
Systematic TUS examination, incl. related anatomical structures and assessment of
region(s) of interest in two planes
Ability to describe the location and character of a parietal pleural lesion (size,
echogenicity, margins, general appearance, signs of invasive growth, possible diagnosis
in case of typical appearance in the clinical context)
Ability to describe the location and character of pleural effusions (semiquantitative
size estimation, echogenicity, general appearance, septations, signs of possible malignancy,
signs of possible underlying non-expandable lung)
Ability to exclude and diagnose a pneumothorax (incl. semiquantitative size estimation)
Ability to describe the location and character of visceral pleural abnormalities (B-lines/
comet tail artifacts, interstitial syndrome, thickened visceral pleura, fragmented
visceral pleura) and to correlate the pattern to a possible diagnosis based on the
clinical context.
Ability to describe the location and character of lung parenchymal lesions (size,
echogenicity, margins, general appearance)
Ability to describe the shape of tumors or nodular abnormalities on the diaphragm
Ability to assess respiratory effort and identify abnormal movement of the diaphragm
Interventional procedures
Ability to use TUS for real-time puncture or drain insertion prior to performing a
pleural puncture or insertion of a pleural catheter or drain
Ability to use Doppler ultrasound to identify possible intercostal vessels at a chosen
puncture or drain insertion site
Documentation and reflection
Ability to write a detailed and systematic report of the ultrasound findings, differential
diagnoses, and conclusion including clinical integration where appropriate
Ability to perform comprehensive and standardized documentation of the ultrasound
examination, including adequate acquisition and storage of images and video files
Recognize limitations of personal expertise and limitations presented by scanning
conditions or artifacts
Describe the effect of limitations on diagnostic certainty and know when to ask for
more expert advice or recommend other imaging modalities
Required training and assessment of ultrasound competencies
To meet the EFSUMB level 1 standard, the trainee should demonstrate basic knowledge
of the normal and pathological sonoanatomy of the thorax and practical skills in performing
a systematic TUS examination, image interpretation, documentation, optimal clinical
integration, and medical decision making based on the TUS examination [2 ]
[22 ]
[23 ]
[34 ]. For EFSUMB TUS level 1, we recommend an approach in which the TUS training and
competency assessment are fully integrated in each training step as described below.
Several competency assessment tests have been developed and validated making this
stepwise approach possible in an evidence-based manner [35 ]
[36 ]
[37 ]
[38 ]
[39 ]
[40 ]
[41 ]. A comprehensive evidence-based training program including all these steps has been
developed and described [42 ].
We recommend the following stepwise approach:
Step 1a – theoretical TUS knowledge: The TUS core knowledge described above can be obtained through lectures, online material,
alternative knowledge platforms (e.g., virtual reality), courses, or textbooks. The
material may be part of an ultrasound training program endorsed by EFSUMB, national
ultrasound societies, or national or international medical societies offering training
curricula in TUS.
Step 1b – theoretical knowledge assessment: The TUS core knowledge obtained as part of step 1a is tested using a validated test.
A validated multiple-choice questions (MCQ) test has been published, and the test
is available upon request [37 ]. The TUS core knowledge test for EFSUMB level 1 should be passed before proceeding
to step 2.
Step 2a – TUS practical skills: The TUS skills should be obtained as part of a practical “hands-on” course. A significant
proportion of the course time should be reserved for “hands-on” ultrasound training
on volunteers and real patient cases. Simulators or phantoms with typical pathological
findings can be used as a partial substitute for real patient cases. In settings with
limited resources or special scenarios (e.g., COVID-19 pandemic), travelling for participation
in a practical “hands-on” course may not be a feasible option. Web-based training
courses may in these cases be the only alternative to no training. Hence, step 2a,
can be modified but should always be followed by steps 3a and 3b to ensure sufficient
bedside clinical training and assessment prior to certification.
Step 2b – TUS skills assessment: The hands-on course (step 2a) should include a post-course assessment of the obtained
skills to ensure that the trainee has reached a sufficient level prior to proceeding
to step 3. The assessment should include direct observation of the trainee performing
a TUS examination. The examination by the trainee should be assessed with a validated
assessment tool by a practitioner who has reached EFSUMB level 2 or a corresponding
level. Several types of assessment tools have been validated for such use (e.g., Objective
Structured Assessment of Ultrasound Skills (OSAUS) and a simulator-based assessment)
[35 ]
[36 ]
[38 ]
[39 ]. If step 2a is conducted as an online course, we recommend the trainee still be
tested using the principles described above. The test can be performed locally at
the trainee’s institution by a practitioner who has reached at least EFSUMB level
2 or a comparable qualification level from a national ultrasound society or a national
or international medical society offering TUS training curricula.
Step 3a – TUS clinical training: After completing steps 1–2, the trainee should perform a reasonable number of ultrasound
examinations and basic TUS interventions (depending on local/national requirements
and practice under supervision) to qualify for a skills assessment for level 1 certification.
The scanned cases should include an appropriate range of normal and abnormal cases.
We recommend that mentorship and supervision of training should be provided by a practitioner
who has reached at least EFSUMB level 2 or a comparable qualification level from a
national ultrasound society or a national or international medical society offering
TUS training curricula (e.g., societies for radiology, respiratory medicine, emergency
medicine, anesthesiology, intensive care, pediatrics). If no local or national guidelines
exist, we recommend at least 30 supervised and approved examinations being performed
on a regular basis during a three-month period prior to proceeding to step 3b.
Step 3b – TUS final assessment and certification: The final competency assessment should include direct observation of the trainee
performing a TUS examination and questioning with regard to the interpretation and
clinical integration of the TUS examination. The ultrasound examination by the trainee
should be assessed with a validated assessment tool (e. g. OSAUS) [35 ]
[36 ]
[38 ]
[39 ], by a practitioner who has reached EFSUMB level 2 or 3 or a corresponding level.
Observations of several TUS examinations of different cases with a variation of findings
are recommended to ensure reliable assessment. Recently, an Objective Structured Clinical
Examination (OSCE) has been validated for performing the final assessment. The TUS
OSCE is based on five assessment stations that the trainee must pass. The five stations
incorporate two MCQ tests, two procedures on simulated patients assessed using OSAUS
and a simulator-based test [41 ]. Video-recorded ultrasound exams could also be used as a more flexible alternative
for the assessment of ultrasound skills if direct observation of performance is impossible,
but since validated video-based assessment tools are currently lacking, this approach
is generally not recommended. EFSUMB level 1 standards will have been met when the
trainee has followed the recommendations above and passed a competency-based assessment
approved by EFSUMB or an international medical society offering TUS training curricula
as mentioned above.
TUS – level 2
Necessary theoretical knowledge
Knowledge and understanding of:
The principles of real-time ultrasound-guided interventions and how to optimize needle
visualization
The different techniques for real-time ultrasound-guided interventions, including
use of needle-guide or freehand technique and in-plane and out-of-plane techniques
The different needle types and equipment used for fine-needle aspiration (FNA) and
core biopsy (CB), and optimal use of these depending on the clinically suspected diagnosis
and the target structure
The assessment and planning of the optimal TUS-guided access path in order to avoid
and minimize the risk of complications (e.g., pneumothorax, hemorrhage)
The handling of specimens depending on the cytopathology/histopathology/microbiology/biochemical
analyses needed (e.g., smearing on microscope slides, basic assessment of adequacy
of obtained specimens, applying fixation techniques, cell block or liquid-based cytology,
optimal handling of pleural fluid)
The general principles of the TNM staging of the most common thoracic malignancies
including consequences for further management
The clinical guidelines for the use of indwelling pleural catheters (IPC)
The principles of ultrasound-guided intercostal nerve blocks (ICNB)
Observation and treatment strategies for common and uncommon severe complications
to TUS-guided interventions and biopsies (e.g., pneumothorax, hemothorax, infection,
air embolism)
The principles of quantitative TUS for assessment of lung parenchymal pathology (e.g.,
computation of the lung ultrasound score, B-lines score)
The principles of quantitative assessment of diaphragmatic function (M-mode, area
method)
The principles of TUS for the quantification of lung loss of aeration and the integration
of quantitative TUS in the monitoring and management of acute respiratory failure
and acute respiratory distress syndrome (ARDS), requiring invasive or noninvasive
respiratory support or extracorporeal membrane oxygenation (ECMO)
Competencies to be acquired
Depending on the specialty and clinical field of practice, four of the bullets below
should be achieved.
Ability to clinically integrate and use TUS for optimal selection of patients for
advanced real-time TUS-guided interventions and other non-TUS-guided invasive diagnostic
or therapeutic procedures in the thorax (e.g., thoracoscopy, pleurodesis, endoscopic,
or transbronchial procedures)
Ability to evaluate signs of invasive growth
Ability to clinically integrate and use TUS to monitor and guide mechanical ventilation
Ability to perform safe and accurate real-time ultrasound-guided FNA and CB of the
chest wall, pleura, lung, mediastinal lesions as well as grossly abnormal structures
in the axillary, supra/infraclavicular regions, and lower neck
Ability to perform an ultrasound-guided IPC insertion
Ability to use ultrasound to assess and monitor the success and potential complications
of a pleurodesis procedure
Ability to perform an ultrasound-guided ICNB
Ability to use TUS to diagnose, monitor, and guide treatment of complications to ultrasound-guided
procedures and other invasive procedures (e.g., thoracoscopy, transbronchial lung
biopsies) in the thorax (e.g., pneumothorax, hemothorax, infection)
Ability to perform quantification of diaphragmatic movement (e.g., M-mode, Area method)
Ability to perform quantitative TUS for the assessment of lung parenchymal pathology
(e.g., computation of the lung ultrasound score, B-lines score)
Ability to correctly quantify lung loss of aeration to phenotype acute respiratory
failure including ARDS, to guide respiratory treatments, and to monitor lung aeration
in patients with acute respiratory failure requiring invasive or noninvasive mechanical
ventilation or ECMO.
Required training and assessment of competencies
As is the case with TUS competency level 1, a stepwise approach is recommended for
level 2:
Step 1a – theoretical knowledge regarding advanced TUS and TUS-guided interventions: The knowledge described above can be obtained through online materials, alternative
knowledge platforms (e.g., virtual reality), or textbooks. The materials used should
be part of an ultrasound training program or a course endorsed by EFSUMB, national
ultrasound societies, or national or international medical societies offering TUS
training curricula.
Step 1b – theoretical knowledge assessment: The knowledge obtained as part of step 1a is tested using an MCQ test. Currently
no validated tests have been published and, until such a test is available, the MCQ
test should be designed in agreement with the general recommendations for construction
and use of MCQ tests. The TUS core knowledge test for EFSUMB level 1b should be passed
before proceeding to step 2.
Step 2a –practical skills for advanced TUS-guided interventions: The advanced practical knowledge and skills for TUS-guided interventions should be
obtained as part of a practical “hands-on” course. At least half of the course time
should be reserved for “hands-on” ultrasound training on simulators or phantoms with
typical pathological findings.
Step 2b – assessment of practical skills for advanced TUS-guided interventions: The practical hands-on course (step 2) should include a post-course assessment of
the obtained practical knowledge and skills, to ensure a sufficient level before proceeding
to step 3. The skill assessment should include direct observation of the trainee performing
an advanced TUS-guided intervention on a phantom or simulator. A generic assessment
tool (e.g., Interventional Ultrasound Skills Evaluation (IUSE)) can be used until
dedicated validated assessment tools for the specific advanced TUS-guided interventions
become available [43 ]
[44 ]. The examination by the trainee should be assessed by a practitioner who has reached
EFSUMB level 2 or a corresponding level.
Step 3a – clinical training for advanced TUS-guided interventions: After completing steps 1–2, the trainee should perform a reasonable number of advanced
TUS-guided interventions (depending on local/national requirements and practice under
supervision) to qualify for a skill assessment for level 2 certification. The interventions
should include an appropriate range of clinical cases and technical difficulty. We
recommend that mentorship and supervision of training should be provided by a practitioner
who has reached at least EFSUMB level 3 or a corresponding level. The clinical, technical,
and practical difficulty of the procedures listed as “level 2” vary significantly.
Additionally, the content of level 2 training will vary from specialty to specialty.
Furthermore, there is no evidence to support a fixed number of examinations or time
to obtain proficiency [32 ]
[33 ]. Hence, it is not possible to provide an evidence-based recommendation for a predefined
minimum required number of interventions prior to proceeding to step 3b. For all examinations
they should be performed on a regular basis for at least a six-month training period
prior to proceeding to step 3b.
Step 3b – final assessment and certification: The final competency assessment should include direct observation of the trainee
performing each of the advanced TUS-guided procedures described above on a phantom
or simulator. The procedure can be assessed using a generic assessment tool until
specific assessment tools have been validated and published [43 ]. The assessment should be performed by a practitioner who has reached at least EFSUMB
level 3 or a corresponding level. Whenever possible, the practitioner performing the
assessment should be an external examiner. If this is not feasible, an internal practitioner
who has not been mentoring the trainee can serve as an alternative. Video-recorded
advanced TUS-guided interventions could also be used as a more flexible alternative
for the assessment of ultrasound skills if direct observation of performance is impossible.
However, since validated assessment tools are currently lacking, this approach is
generally not recommended. EFSUMB level 2 certification is obtained when the trainee
has followed the recommendations above and passed a competency-based assessment approved
by EFSUMB or another international medical society offering TUS curricula.
TUS – level 3
Necessary knowledge
Knowledge of the principles of advanced ultrasound technologies such as elastography
and contrast-enhanced ultrasound (CEUS) and their relevance for thoracic imaging
Ability to describe the ultrasound characteristics of rare pathologies in the thorax
Profound knowledge of the state of the art in thoracic ultrasound and, if possible,
active scientific activity in this field
Competencies to be acquired
Ability to perform diagnostic TUS at an advanced level with a representative number
of rare or demanding pathologies
Ability to use advanced technologies such as elastography or CEUS as a supplementary
diagnostic tool or to guide TUS-guided interventions [12 ]
[17 ]
[28 ]
[45 ]
Acceptance of referrals from level 1 and level 2 practitioners and undertaking of
more complex ultrasound examinations
Ability to use required skills to develop advanced services under appropriate governance
Mentoring and supervision of level 1 and 2 trainees and practitioners
Either participation in or experience with faculty-level teaching of ultrasound courses
at the local, national, or international level
Profound knowledge of the state of the art in thoracic ultrasound and, if possible,
active scientific activity in this field
Required training and assessment of competencies
Advanced diagnostic ultrasound skills are required, and physicians should regularly
perform TUS corresponding to TUS level 2 for at least 12 months to obtain level 3
certification. It is also a requirement to be involved in teaching and, if possible,
ultrasound research. Candidates for level 3 certification need to document the above-described
competencies, which should be assessed by EFSUMB experts or experts from corresponding
international medical societies offering TUS training curricula.
Maintenance of TUS skills – all levels
Practitioners should regularly, on a weekly basis, perform or supervise TUS examinations
and relevant TUS-guided procedures to maintain competence. There should be continuing
professional development and updating of practice. Attendance at appropriate ultrasound
courses or conferences relevant to TUS and its clinical use, together with regular
reviews of the current literature, are expected. Operators that undergo prolonged
periods of time (> 12 months) without exposure to TUS should repeat the relevant competency
tests prior to re-starting clinical TUS. If the competency tests are not passed, structured
training and assessment as described in this position paper should once again be completed
before re-starting clinical TUS. The amount of time to be considered a prolonged period
of time will be defined on an individual basis based on skill level and experience
prior to the period without exposure to TUS.
