Point-of-care ultrasound (POCUS) offers the anaesthesiologist a suite of bedside tools to answer specific questions in daily perioperative medicine practice, narrow differential diagnoses, and improve the safety of routine procedures.1,2,3,4,5,6,7,8 Ultrasound technology made its way into anesthesia practice almost two decades ago when it was implemented as procedural guidance for regional anesthesia9 and vascular access.10 At the same time, intraoperative transesophageal echocardiography became an indispensable tool for anesthesiologists in the cardiac operating room.11,12 The evidence base for basic transesophageal13 and transthoracic echocardiography in non-cardiac surgery14 has been increasing in time with the demand for training in these skills. A recent survey of Canadian academic departments of anesthesiology15 reported that 13 of 17 (76%) of the programs surveyed had some focused, POCUS training as part of their residency training; 12 of 17 (70%) believed it should be part of the anesthesia residency curriculum. A key challenge faced by any program wishing to introduce POCUS training is “What are we going to teach?”

In a recent “call to action”, Mahmood et al.16 suggested 25 diagnostic and 19 procedural uses of ultrasound. Their list (Table 1) ranges broadly in scope from assessment of fluid status to confirmation of correct placement of a urinary catheter. Clinicians will undoubtedly argue the relative merits of the different systems evaluated by ultrasound and how each fits in a POCUS curriculum. Indeed, a recent survey of Canadian anesthesia residency program directors15 found significant disagreement on the techniques to be acquired during residency training. The majority of responders considered venous and arterial access, peripheral and neuraxial blocks, lung ultrasound, transthoracic echocardiography, and assessment of the inferior vena cava as “important” or “very important”. These only include cardiac and lung ultrasound as diagnostic applications. Other POCUS applications of specific interest to anesthesiologists such as regional anesthesia, airway, and gastric assessment were not considered of primary interest.

Table 1 Ultrasound applications relevant to anesthesiology and perioperative medicine
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The purpose of this narrative review is to identify the POCUS applications relevant to anesthesiology and perioperative medicine. We will begin with a broad evaluation of POCUS training standards from other kindred specialties such as emergency medicine and critical care and then narrow our focus to anesthesiology-specific training standards in use elsewhere. Where possible, we will cast our descriptions in the language of skill levels and specific applications and conclude with future challenges that must include continuing professional development.

Point-of-care ultrasound outside the operating room

Emergency medicine has pioneered the introduction of POCUS in clinical practice and includes ultrasound as a learning objective in its Canadian postgraduate curricula. The International Federation of Emergency Medicine (IFEM) released a consensus document to guide development of POCUS training programs in Emergency Medicine around the world.17 Their proposed framework is, however, very generic and seems to fulfill the needs of different specialties for a variety of clinical, infrastructure, and logistical demands (Fig. 1). According to this guide, curriculum development involves first definition of practice and, in parallel, development of the methodology of training for each POCUS application. The definition of practice requires identification of core and advanced (enhanced) ultrasound application; of these, some are diagnostic and some procedural. The methodology of training is then structured in four steps: introduction to the application, development of experience, achievement of competence, and maintenance of competence.

Fig. 1
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Framework for point-of-care ultrasound curriculum development by the International Federation of Emergency Medicine

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The Canadian recommendations for critical care ultrasound training and competency are aimed at all Canadian critical care providers and describe a framework for training and a pathway to achieving competency.18 They are largely based on the American College of Chest Physician statement for critical care ultrasonography19 and the International Expert Statement on Training Standard for Critical Care.20 Specific ultrasound applications are divided into basic and optional (Table 2). The framework for training defines the minimum requirements for a centre to maintain a training program and training supervisors named “local experts”. Similarly to what was described for emergency medicine, the training pathway consists of four steps: introductory training (course/workshop based), portfolio completion (acquisition of case log), competency assessment (review of log and skills assessment) and quality assurance, and maintenance of competence (continuing education and case review).

Table 2 Summary of national and local POCUS curricula
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Point-of-care ultrasound for anesthesiologists

There is no current consensus on what perioperative POCUS comprises and no national curriculum in Canada. The only published national ultrasound curriculum is from the Association of Anaesthetists of Great Britain and Ireland and the Intensive Care Society.21 The curriculum is directed, without distinctions, to both anesthesia and intensive care trainees and serves as a guide to future full integration of POCUS training into the Royal College of Anaesthetists (RCoA) residency training.

The Curriculum defines three levels of competency: level 1(core), level 2 (extended), and level 3 (advanced). Level 1 includes generic competences that should be achieved during standard postgraduate specialist training while level 3 is comparable to specialist training of cardiology and radiology.

The guideline defines basic essential elements of knowledge and skills that represent the foundation of any level of competence and are included in a detailed ultrasound competencies list on the following areas: basics of ultrasound, administration, interpersonal communication, scanning, and needle-guidance technique. These are followed by a list of knowledge and practice skills including the minimum pathology variation for each POCUS application. An example of the detailed checklist for vascular access is shown in Fig. 2.

Fig. 2
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Example of assessment checklist from the Royal College of Anaesthetists of the United Kingdom31

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As in Canada, the United States has no formal POCUS curriculum for anesthesiologists but several local programs have been well described. Ramsingh et al.22 described the Focused PeriOperative Risk Evaluation Sonography Involving Gastro-Abdominal Hemodynamic and Trans-thoracic ultrasound (FORESIGHT) comprehensive perioperative POCUS curriculum. While not adopted nationally, the curriculum developed and implanted at the University of California Irvine was based on six clinical Accreditation Council for Graduate Medical Education (ACGME) core competencies for anesthesiology. The curriculum includes echocardiography, lung, abdominal, airway, optic nerve sheath ultrasound, and vascular access. Specific objectives were defined for each application. The curriculum was delivered over a two-year period. The initial basic training consisted of a weekly 20-min lecture followed by a 25-min human model or simulation practice delivered over a six-month period. Simulation training included specific ten-minute scenarios on key components of each of the POCUS applications included in the curriculum. This was followed by supervised hands-on training. As part of an evaluation of the curriculum, students were randomly allocated to receive pathology training in their second year. Knowledge was assessed at various time points using standard multiple-choice questions. Point-of-care ultrasound competence was assessed on real clinical scenarios; residents who received pathology training showed a higher level of competence.

Another successful local model was proposed by the group from Harvard23 that included a multimodal curriculum combining didactic modalities with on-line learning, simulators, live model scanning, and case-based discussions. The curriculum was structured to provide an introduction to basic knowledge, opportunities to build a portfolio, and a final evaluation. The basic knowledge was delivered over 13 days and included the following POCUS applications: vascular access, regional anesthesia, transthoracic and transesophageal echocardiography, lung, and focused assessment with sonography in trauma (FAST) abdominal scanning. A set number of scans was defined for each modality and the final assessment was based on a detailed checklist. None of the anesthesia-specific programs cited, however, include maintenance of competence as per IFEM and Canadian Critical Care ultrasound frameworks.

Curriculum delivery

If we are to incorporate POCUS training on a national scale in Canada, we must prepare to train both students and their faculty. The published POCUS curricula and guidelines in anesthesiology training share a similar structure of basic ultrasound knowledge building followed by manual skill development for image acquisition and procedures. These two initial steps are followed by need for practice and portfolio building. Many teaching models have been proposed in POCUS training and vary from hands-on training on patients to self-learning models and simulations.8 A systematic approach to POCUS training was proposed in the I-AIM framework that theorizes a stepwise approach to POCUS competency through the acquisition of fundaments of Indication, Acquisition, Interpretation, and clinical decision-Making.

Available guidelines on POCUS curriculum development do not mandate a specific didactic strategy and allow individual organizations to rely on their available resources. A Canadian university has reported on the feasibility and user satisfaction of a compact POCUS training course within its residency training program.24 The curriculum consisted of four weekly two-hour theoretical sessions followed by an hour of hands-on scanning. The study proved the feasibility of curriculum delivery but was limited by the impact assessment, based on pre-post course test knowledge improvement, and a curriculum limited to cardiac scanning.

Despite their initial high cost, the use of simulators has proven very efficient in shortening training time and speeding up the learning curve.25,26 For this reason, their use may have an even stronger role in the training of practicing anesthesiologists. Similarly online resources27,28 allow continuous learning “on demand”, fit the needs of newer generations of learners, and allow for a “flipped” classroom model.

Challenges to establishing Canadian POCUS training

Lack of trained anesthesia staff is still considered a primary limitation to the introduction of POCUS in anesthesia residency curricula. Although over 75% of Canadian anesthesiology training programs include some element of POCUS in their training, only 25% of faculty were using focused cardiac ultrasound in their daily practice.15

Surprisingly, only 177 of 379 (46%) surveyed members of the Society of Cardiovascular Anesthesiologists practice cardiac ultrasound on a daily basis and 152 of 379 (40%) were comfortable teaching it.29 This concentration of expertise greatly limits opportunities for bedside instruction, assessment of competence, and integration of the technical and cognitive aspects of scanning. Rapidly creating a pool of practicing anesthesiologists capable of mentoring trainees, or one another, presents a formidable challenge.

The RCoA included in their guidelines training of anesthesia staff as a specific clinical pathway to mitigate some specific challenges such as access to supervision and feedback. Nevertheless, the overall curriculum is structured in parallel to the trainee pathway described above and shares the same content. A recent report described the successful introduction of POCUS training among staff in a university anesthesia department for pre- and intra-hospital acute care.30 The curriculum included basic heart and lung scanning and was delivered in a flipped classroom mode where the staff enrolled had to complete a set of e-learning modules prior to attending a one-day hands-on course followed by one day of supervised scanning. After this introduction staff were left to unrestricted practice and tested at different time points on healthy volunteers. All study participants showed good skills and long-term retention of knowledge. Time allocated to POCUS practice, difficulty in image acquisition, lack of knowledge, and scant evidence for some applications specific to perioperative care were identified as limiting factors to the introduction of POCUS among anesthesiology staff in the perioperative setting.

Assessment of competency remains a challenge31 and mostly relies on subjective observation and checklists. Point-of-care ultrasound is not yet recognized as a milestone in anesthesiology training in the USA by the ACGME. The Royal College of Physicians and Surgeon’s of Canada subspecialty committee for anesthesiology has defined bedside ultrasound in hemodynamic management as a new entrusted professional activity within the new Competency by Design (CBD) residency training platform. The University of Ottawa has recently proposed an integrated anesthesia POCUS curriculum that includes assessments and milestones. This may be a pilot project on which to build a National Curriculum.32

Once defined, the assessment of POCUS-specific competencies remains problematic. There is little doubt that direct observation of performance on real patients is the preferred means of assessment; however, the lack of trained faculty mentioned above limits opportunity for such evaluations. Further limitations to one-on-one bedside teaching include ethical considerations and inconsistent patient pathology. Assuming one can accurately assess the technical and cognitive competencies of POCUS, there is no consensus among authors on what constitutes the minimum numbers of scans for each application. While for some of the applications, authors have assessed the learning curve to achieve competency, for most the number suggested by many guidelines and consensus documents is based on expert opinion without solid evidence.

To obviate some of these limitations, the Objective Structured Clinical Examination (OSCE) method has been proposed for POCUS training.33 Image acquisition skills shown in model patients—often young, healthy, and compliant—may not be easily reproduced in the less controlled population in the perioperative period. While modern simulators are producing increasingly more realistic pathologic representations, the variety of pathology may still be limited and often artificial. Specific rapid assessment tools have been proposed by other specialties34 but their validity for anesthesia and the perioperative setting remains unknown. Definition of maintenance of competency remains a challenge as it has rarely been addressed in current literature.

Future directions

In the CBD framework, POCUS objectives need to be integrated in a specific CanMEDS format. Point-of-care ultrasound-specific training milestones and entrustable professional activities will need to be defined to harmonize a new curriculum with the Royal College of Physicians and Surgeons of Canada’s Competency by Design framework (http://www.royalcollege.ca/rcsite/cbd/cbd-assessment-e). Use of this framework raises several challenging questions. How will programs define specific scenarios and matching skills that provide clearly evaluable milestones? How will non-technical skills such as reporting (Communicator) and continuous quality improvement (Health Advocate) be assessed and mapped to CanMEDS 2015 roles? (Table 3).

Table 3 Specific POCUS objectives for anesthesia training in CanMED format
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A first step in the development of a Canadian POCUS curriculum is the clear identification of basic and advanced applications. A common curriculum for these basic skills, based on best evidence and comparable guidance from other agencies, is required if these skills are made a mandatory element of Canadian anesthesia training; POCUS training should include basic and advanced applications (Table 4).

Table 4 Milestones in core curriculum
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Introduction to the general principles of ultrasound physics, probe selection, image orientation, and optimization should constitute the foundation of the POCUS discipline and be shared with other operative ultrasound-guided applications such as line insertion and regional anesthetic techniques, which we believe should be treated separately from POCUS. Core POCUS competence should include broadly accepted basic modalities currently supported by strong scientific evidence such as focused cardiac ultrasound,6 lung ultrasound,7 and FAST.8

Basic POCUS should aim at providing qualitative assessment and answer binary questions as part of clinical decision-making. Applications of each modality should be limited to the use of basic two-dimensional imaging, achievable with any ultrasound system. They must include acquisition of basic views and aim at identifying specific conditions such as ventricular failure, hypovolemia, tamponade, pneumothorax, pleural effusion, and intra-abdominal free fluid.

Each POCUS modality should constitute a core curriculum module built on the I-AIM framework.35,36 Self-directed learning though online modules or other reading material and logged simulation training (whenever available) should precede hands-on training on volunteers. Image interpretation should be acquired though supervised case discussions and self-directed online case review. Milestones for core module completion include image acquisition on healthy volunteers and completion of a basic image acquisition portfolio. The extent of the portfolio should be defined based on current evidence and other societies’ guidelines. The trainees must complete an image interpretation log whose extent is to be defined and include normal and pathologic studies of varying image quality. Image acquisition skills should be assessed by direct observation on volunteers and review of the portfolio.

Core curriculum is to be delivered early during the residency training to allow enough time for integration into clinical decision-making during transition to practice.

This phase would focus on the daily application on patients. Final skills assessment should thus be based on demonstration of competency in all defined basic clinical scenarios and achievement of CanMEDS roles including POCUS training.

Definition of mentors and supervisors would initially have to rely on individual experience and availability at each centre; however, definition of scholar competencies has to be defined based on a specific training pathway in the future.

Conclusions

Despite an increase in the introduction of POCUS curricula in anesthesia and perioperative medicine, significant variability exists among curricula. This variability is compounded by a lack of national standards for POCUS competencies for the perioperative setting. The development of a national core POCUS curriculum for perioperative POCUS for anesthesiologists is necessary to assure standard of practice as it is perceived as a limiting factor to the development of perioperative POCUS practice despite a growing body of effective applications in perioperative medicine. Definition of scope of practice of POCUS in the perioperative context is the first step to development of a common curriculum. Generic guidelines and POCUS learning frameworks are available to guide curriculum development; however, definition of training goals has to be adapted to individual national residency curricula. They should also incorporate specific guides on how to train and establish competency for practicing anesthesiologists.

To rapidly advance training in and use of POCUS in perioperative care, one could look to the advancement of intraoperative transesophageal echocardiography where practice and training are clearly defined by guidelines by joined anesthesiologists’ and echocardiographers’ societies. A similar opportunity might be found among specialities who share anesthesiologists’ interest in trauma and critical care. Finally, new curricula should incorporate newer teaching approaches including simulation and online learning. Assessment and maintenance of competency remain a challenge and the methods used may be different when assessing anesthesia trainees compared with staff anesthesiologists.