Lung ultrasound is not a fishing expedition

Abstract

Lung ultrasound(LUS) has rapidly gained favour in critical care setting, due in part to its safety profile, speed and convenience. We must guard against over-enthusiastic application leading to unconscious incompetence. Lung ultrasound combines the interrogation of real pathologies (consolidations, diaphragm and pleural fluid), with interpretations of artefacts originating at the pleural surface (A, and B lines). Two separate settings are required - one to optimise tissue imaging, and one to optimise the creation of artefacts. The probe and preset are selected to interrogate the most important clinical question. This necessitates the clinical question be generated FIRST. Lung ultrasound is not a ‘fishing expedition’. Even with optimal image acquisition - single system LUS is an imprecise tool, either sensitive, or specific. Before picking up a probe, one must reason down to a simple question, estimate pre-test probability, and enquire of confounders. LUS should conclude the examination, not precede it. History and examination should decide the LUS protocol, not the reverse. Recent subgroup analysis of our LUS+2014 project suggests that it is not enough to teach good acquisition of lung ultrasound scan, one must follow through with discussions on the integration into care. We will use illustrative cases from our project to model the integrative thinking, using the following questions as a guideline.