LUS (Let’s Use Sonography) to Diagnose ARDS!

July 5, 2023

Written by Megan Hilbert

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The LUS-ARDS score can make a diagnosis of acute respiratory distress syndrome (ARDS) easier, particularly in patients who can’t have CT scan. The LUS-ARDS score performs similarly to the standard of care (Berlin criteria plus CXR evaluation) in diagnosis of ARDS in ventilated patients.

Another wave of ARDS research
ARDS can be a difficult diagnosis to make and has a mortality of up to 40%. Knowing a diagnosis of ARDS early allows for appropriate management including lung-protective ventilatory strategies. With over-crowding in hospitals and increased boarding times within Emergency Departments, this approach could help guide management until critically ill patients are able to be transported to the ICU.

This was a multicenter prospective observational study that had both a derivation and validation cohort in order to create the LUS-ARDS score (see Table 3 from the paper inserted below; note posterior lung field evaluation was not included as it did not lead to increased diagnostic accuracy). Performance of the LUS-ARDS score was compared against gold-standard of evaluation of clinical data, blood gas information, and chest imaging by three experts. Ultimately, the score demonstrated an AUROCC (area under the receiver operating characteristic curve) of 0.84 (95%CI 0.79-0.89). The low LUS-ARDS score cut off was 8 points, high cut off 27. This performed better than other ultrasound based evaluations of ARDS, which tend to have either high specificity or sensitivity but not both. Strengths of this article include its prospective nature and external validation. Limitations include the fact that the 12-region protocol cannot be completed on all patients (ie: due to presence of chest tubes).

How will this change my practice?
I honestly believe that this paper and its findings are most clinically useful to our ICU colleagues. Having said that, if I have an intubated patient that remains in the ED for a long period of time and I am considering making changes to my ventilator management then I may consider grabbing an ultrasound to determine the likelihood of an ARDS diagnosis.

Source
Lung Ultrasound Prediction Model for Acute Respiratory Distress Syndrome: A Multicenter Prospective Observational Study. Am J Respir Crit Care Med. 2023 Jun 15;207(12):1591-1601. doi: 10.1164/rccm.202210-1882OC.