Ask The Expert: Dr Giovanni Volpicelli on lung ultrasound in COVID-19

We had the chance to catch up with lung ultrasound maestro Gio Volpicelli (via video conference) about his thoughts around LUS in Covid-19! Some interesting points made and lots of food for thought.

Key points

• PLAPS point is not useful - most pathology in Covid-19 is in posterior zones which needs to be evaluated more thoroughly.

• For those that say now is not the time to start learning LUS, Volpicelli says that the basics are very quick to learn - like learning the basics of a new language. Short training duration - lots of exposure at the moment.

• The Chinese started using CT for all patients at the start and as they progressed they realise that it is a peripheral based disease that is amenable to LUS evaluation.

• Sensitivity for COVID diagnosis in ED 1. CT 2. LUS 3. CXR

• For COVID pneumonia only, if negative LUS findings then consider other causes of dyspnea.

• CXR is inferior - GV stopped doing CXR except in certain circumstances.

• CT reserved for complex patients in which complications suspected eg. chronic lung disease.

• Walk test gets the thumbs down from GV. May be useful if totally overwhelmed (crowding++ or not possible to isolate) and have no time. Otherwise better use LUS to diagnose COVID19.

• Exercise caution in patients that have evolving (early) disease with recent onset of symptoms even if positive LUS. These patients need close follow up to monitor for rapid deterioration. These are a different cohort to those that have had disease for 2 weeks and are resolving.

• LUS is preferred for diagnosis and qualitative evaluation especially when coupled with timing of symptom onset. CT is preferred for disease quantification.

Prognostication

• LUS not useful. GV has seen patients with consolidation at bases that are clinically well and patients with interstitial pattern that require RSI within 3 hours.

• LUS is useful to diagnose COVID (particularly in early stages) but not currently useful for risk stratification/prognostication.

• PCR has poor sensitivity. If clinical suspicion of COVID then move to LUS or CT.

• PCR sensitivity depends on who is doing it (ie. technique/operator factors).

• Of all the blood test - leucocyte count is most useful.

• Pro-calcitonin is useful to rule out bacterial co-infection in COVID-19 (if low).

Technique

• Use convex transducer (presume this is a curved linear probe)

• Longitudinal (traditional) orientation is perferred overall - quick, easy for beginner to use, can move in a V-shape down the chest wall. Transducer is placed across the ribs

• Record 8-10s clips for review later

• Anterior chest - longitudinal orientation preferred

• Lateral chest - use longitudinal orientation

• Posterior chest - superior area use longitudinal orientation, below the scapula use oblique orientation (transducer between the ribs)

Proning and CPAP works

• Improvement in 3 to 4 hours in condition and LUS findings.

• Caution when you remove CPAP - patients may rapidly deteriorate.

• Helmet/hood is preferred for CPAP.

• LUS does not predict success response to CPAP.