International Lung UltraSound Analysis (ILUSA) Study

During the current COVID-19 outbreak, all patient groups have been affected, also the most fragile such as the pregnant women. Although experts provided general suggestions on the best management of pregnant women with suspected or confirmed COVID-19, these considerations are mainly based on retrospective studies or case series. No prospective study is currently available about management of confirmed or suspected patients during pregnancy. Moreover, only limited outcome data is available on the management of asymptomatic SARS-CoV-2 positive pregnant patients, many of whom subsequently develop disease symptoms.

The current gold standard for the etiological diagnosis of COVID-19 infection is analysis of respiratory tract specimens by (real-time) reverse transcription polymerase chain reaction (RT-PCR). However, this test has a high false-negative rate, due to both nasopharyngeal swab sampling error, which often requires repeat sampling, and changing viral burden. Currently, high-resolution computed tomography (CT) is the main tool for primary diagnosis and evaluation of disease severity in patients affected by COVID-19 infection. Chest CT scan also demonstrated a specificity even superior to the nasal/pharyngeal swab for diagnosis. Yet, radiation exposure should ideally be avoided at all times in pregnancy. A radiation-free point-of-care diagnostic tool, such as lung ultrasound (LUS) examination, would be particularly useful for assessing the lungs of pregnant women. Indeed, LUS examination has recently been suggested by the Chinese Critical Care Ultrasound Study Group and the Italian Academy of Thoracic Ultrasound as an accurate tool to detect lung involvement during COVID-19.

In pregnant patients, LUS could be a valid alternative imaging tool to thoracic CT to guarantee appropriate care for these patients. Symptomatic patients with a low risk of developing serious disease may be possibly reassured, and could leave the hospital soon after delivery. On the other hand LUS could possibly indicate patients at higher risk for future need of oxygen or ventilation support, and who might need more careful monitoring and longer hospitalization. In view of the wide availability in delivery suites, the low cost and easy bedside application LUS could also be readily repeated during patient follow up as needed. LUS has been traditionally employed by non-radiologists as an adjunctive clinical instrument. Obstetricians represent a category of clinicians who use ultrasound in their daily routine practice. From a technical point of view, examination of the lungs at the time of obstetric ultrasound evaluation could be feasible for obstetricians and gynaecologists.

Currently there is a great need for an accurately and rapid assessment of patients suspected for Covid-19. Like CT, LUS can potentially help with the initial triage of patients but also help track the evolution of the disease. LUS can be used in every setting, including settings with limited infrastructure, allowing the reduction of disparities in trials participation. LUS is also a practical approach that can be used by obstetricians/gynecologists, who are the primary care givers in the labour and delivery room.

The International Lung UltraSound Analysis (ILUSA) Study is an international multicenter prospective explorative observational study to assess the predictive value of LUS in Covid-19 suspected and diagnosed pregnant patients.