Lung ultrasound through the oesophagus, added to a probe already in place

Design

multicentre observational cohort study using prospectively collected registry data

Population

379 transoesophageal echocardiography examinations in ventilated adults with shock across 23 hospitals

Primary outcome

operator-reported identification of shock aetiology and change in management

Effect

86.5% vs 75.3% identification (OR 1.95, 95% CI 1.02-3.72); management change 78.1% vs 71.7% (not significant)

Across 23 hospitals contributing to a resuscitative transoesophageal echocardiography registry, 379 examinations in ventilated adults with shock were reviewed. In 96 of them (25.3%) the operator also performed transoesophageal lung ultrasound, using the same probe already in the oesophagus.

Operators reported identifying the cause of shock in 86.5% of examinations that included lung views against 75.3% of those that did not (odds ratio 1.95, 95% CI 1.02-3.72, p = 0.04). Reported changes in management were more frequent but not significantly so (78.1% against 71.7%). The additional time was 2.5 minutes at the median, and complications were rare and similar in both groups.

The outcome here is what the operator said they found, recorded by the operator, unblinded. That is a weak endpoint and the authors say so, calling for standardised acquisition, independent adjudication and patient-centred outcomes. What the study does establish is feasibility: the probe is already in, the views are obtainable, the extra time is trivial, and nothing bad happened. For a unit already doing resuscitative transoesophageal echocardiography, that is enough to try it. For a unit that is not, this is not a reason to start.

• Only relevant where resuscitative transoesophageal echocardiography is already established.
• Median additional procedure time was 2.5 minutes, and complications were no more frequent.
• The outcome was operator-reported and unblinded, so the diagnostic gain is not independently confirmed.
• Examinations were predominantly performed by intensivists.
• Transthoracic lung ultrasound remains the first-line approach in most units.

Why it matters

It asks whether a probe already sitting in the oesophagus should be used to look at the lungs before it comes out.

Don't overread it

Operator-reported, unblinded outcomes in a registry - this shows feasibility, not diagnostic benefit.

The statistics, in plain English

An odds ratio of 1.95 with a lower confidence limit of 1.02 is only just distinguishable from no effect, and the outcome is what the person who chose to do the extra scan then reported having learned from it. That circularity is the study's main weakness: operators who add a test tend to report that it helped. Feasibility and safety, by contrast, are measured directly and are the parts worth carrying away.

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