Multi-organ ultrasound could rule out pulmonary embolism in critically ill COVID-19 patients and reduce the need for CT pulmonary angiography
Multi-organ ultrasound might be of value in ruling out a pulmonary embolism (PE) in critically ill patients with COVID-19 and potentially reduce the need for computed-tomography pulmonary angiography (CTPA). This was the conclusion of a study by researchers from the department of Acute Internal Medicine, Amsterdam UMC, the Netherlands.
Among those who are critically ill with COVID-19, studies suggest an increased risk of thrombo-embolism and subsequent death. In fact, the incidence of PE is reported to be around 2.6 – 8.9% of COVID-19 in hospitalised patients and up to one-third of those requiring intensive care unit (ICU) admission, despite standard prophylactic anticoagulation. In a 2010 survey, the majority of the radiologists indicated that CTPA is the new reference standard for the diagnosis of pulmonary embolism. However, in cases where CTPA is unavailable, a 2020 meta-analysis has indicated that cardiopulmonary ultrasound may be useful in areas where CTPA is unavailable or unsuitable, as this modality can help detect right ventricular strain (RVS) which has a high degree of specificity for a PE. In addition, an emergency department study concluded that the use of multi-organ ultrasound is more sensitive than single-organ ultrasonography and increases the accuracy of clinical pre-test probability estimation in patients with suspected PE.
However, whether multi-organ ultrasound would be of value in ruling out a PE among critically ill patients with COVID-19 is unclear and was the objective of the current study by the Dutch team. They set out to compare the diagnostic value of lung, deep vein and cardiac ultrasound both separately and in combination for the detection of PE. Included patients were adults (> 18 years) admitted to an intensive care unit and for whom a multi-organ ultrasound scan was performed within 24 hours of a CTPA.
Multi-organ ultrasound scan results and pulmonary embolism
A total of 140 CTPA scans were performed in 70 consecutive patients with a mean age of 67.5 years (80% male) and patients underwent 126 lung, 123 deep vein and 125 cardiac ultrasound scans.
The diagnostic accuracy of sub-pleural consolidations was 42.9% (95% CI 34.1 – 52), and 75.6% (95% CI 67.1 – 82.9%) for deep vein ultrasound and 74.4% (95%CI 65.8 – 81.8%) for RVS on cardiopulmonary ultrasound.
When the signs of multi-organ ultrasound scans were combined, the sensitivity was high at 87.5% (95% CI 67.6 – 97.3) although the specificity was low at 25%.
The authors concluded that while the use of individual single site ultrasounds were of limited value on their own, multi-organ ultrasound had a higher sensitivity and could therefore be of value at ruling out a PE. They described how these data suggested the use of multi-organ ultrasound has the potential to reduce the amount of CTPA’s undertaken adding that since devices were hand-held and hence more accessible, scanning could be undertaken by intensive care personnel.
Lieveld A et al. Multi-organ point-of-care ultrasound for detection of pulmonary embolism in critically ill COVID-19 patients – A diagnostic accuracy study J Crit Care 2022