Table 2.

Core principles of point of care ultrasound in emergency medicine

Core principle	Rationale	Considerations
A. The remit of the PoCUS USI must be well defined a priori	The wide range of potential tissues, organ systems and differentials encountered in EM – is in contrast with the PoCUS clinician typically not being competent to image across all such areas/differentials. Additionally, much of the tissue and organs imaged are not relevant to the EM provider Therefore, to ensure patient safety and to defend against litigation risk, the PoCUS clinician must only use PoCUS within their area of established competency	Given the “emergency” nature of EM, this means that prospective agreement regarding remit is essential The largely binary nature of EM PoCUS decision making (i.e., the “rule in” principle) complements this
B. The standard of PoCUS USI must be the same as that of non-PoCUS users of USI	Whilst the scope of PoCUS is artificially narrow (core principle A), the standards must be the same as for radiologists and sonologists. This reflects a fundamental commitment to quality of care and patient safety	Such standards include competency in the imaging undertaken, the reporting of USI findings, recognition of boundaries of imaging competency, etc.
C. The imaging performed should align with subsequent clinical decision making and resource availability	Aligning with core principle A, PoCUS USI should be undertaken as part of a meaningful clinical decision making/treatment algorithm. This will be framed by the availability of resources to address the clinical problem(s); considerations include patient prognosis, local resources and likelihood of accessing tertiary facilities (where appropriate)	Core principle C is highly “site dependent” and may be influenced by transient resource demands (e.g., natural disaster)

PoCUS: Point of care ultrasound, EM: Emergency medicine, USI: Ultrasound imaging