Given the critical importance of diagnostic accuracy when performing FoCUS, a logical next question is how much training is required to become proficient in this skillset? Cardiac ultrasound interpretation is inherently subjective and operator-dependent, such that even senior echocardiographers routinely disagree with one another and even with themselves when visually assessing pathologies such as left ventricular regional wall motion abnormalities (Blondheim et al.,
2010). Given the difficulty that expert echo-cardiologists have interpreting TTE, many healthcare systems are understandably reluctant to permit clinical decision-making based solely on FoCUS examination findings. To maximize patient safety, providers seeking to perform FoCUS should first receive adequate training and demonstrate competency in this skillset. Unfortunately, there exist many ambiguities regarding credentialing and privileging for point-of-care ultrasound generally and FoCUS specifically (Kimura,
2017). Existing well-developed guidelines for competency in other realms of echocardiography, including perioperative transesophageal echocardiography (TEE), provide a stark contrast to the lack of guidelines for FoCUS. This ambiguity makes it difficult for many to adopt FoCUS comfortably into their practice (Alfirevic,
2015).
The most stringent recommendations for hand-carried ultrasound usage come from professional cardiology and echocardiography organizations, which recommend achieving at least level 1 competence in order to independently perform and interpret hand-carried ultrasound. Training for level 1 includes performing 75 examinations, interpreting 150, and completing 3 months of didactic learning (Beaulieu,
2007). However, these competency requirements have been designed with the cardiovascular specialist in mind and thus are geared toward quantitative echocardiography rather than the use FoCUS to help answer qualitative questions. Other specialties have released less stringent requirements, e.g., emergency medicine has suggested 25–50 exams are adequate to achieve competency in FoCUS (Ultrasound Guidelines,
2017). In the critical care arena, a recent publication described basic competency as the ability to achieve high-quality images on all standard views, ability to distinguish normal vs. abnormal and seek appropriate referrals after completing 50–100 exams (Price et al.,
2008). The British Society of Echocardiography calls for 10 supervised exams and 50 individually acquired exams with interpretation overseen by a mentor in order to become accredited in focused intensive care echocardiography (FICE) (Echocardiography BSo,
n.d.). In contrast, a different expert consensus statement in critical care concluded the following: (i) 30 fully supervised FoCUS exams may be the minimum required to achieve competence in image acquisition; (ii) the minimum number of studies required to achieve competence in image interpretation should be based on teacher/supervisor determination (International expert statement on training standards for critical care ultrasonography,
2011). Lending support to this latter consensus statement, Millington et al. studied the learning curve of FoCUS image acquisition and image interpretation skills among residents from multiple acute care specialties (Millington et al.,
2017). Prior to the start of the study, the learners performed a median of 8 training exams and received extensive didactic preparation consisting of 2 days of lectures and a month-long elective in echocardiography. The authors found that competence in image acquisition plateaued at around 20 exams, but competence in image interpretation required a larger volume of studies (Millington et al.,
2017). Based on these studies, a preoperative provider new to cardiac ultrasound would likely need to undergo a period of didactic training and perform at least 20–30 supervised exams, in order to acquire images competently. Further, this individual would need additional oversight by a more experienced practitioner for an unknown period of time until competency in image interpretation is demonstrated. Notably, this amount of training would only qualify the provider to perform and interpret FoCUS, not TTE. It thus becomes useful to understand the potential pathologies not seen with FoCUS that are relevant to the perioperative care of patients.