Implementation of lung ultrasound in the triage of pregnant women during the SARS-CoV-2 pandemics

Table 1 Studies reported the use of lung ultrasound in pregnant women with coronavirus disease 2019

Ref.	Country	Type of study	Cohort	Diagnosis	LUS technic	Conclusion
Buonsenso et al[30], 2020	Italy	Case report	4 pregnant women at 24, 38, 17, and 35 wk gestational age	LUS was carried out before the positive RT-PCR result. Nasopharyngeal swab RT-PCR confirmation	14 regions evaluation with the convex probe.	LUS was correlated with CT findings, this tool should be considered in clinical deterioration to check the lung status for COVID-19 pneumonia and LUS might be preferred to chest X-ray in pregnant women
Deng et al[31], 2021	China	Retrospective study	27 of pregnant women at the third trimester, 8 of them at the second trimester, and 4 of them at the first trimester	29 of them with pharynx RT-PCR testing and 10 with epidemiologic history, symptoms, and imaging results	12 zones: 2 anterior zones, 2 lateral zones, and 2 posterior zones per side. Each zone was scored 0 to 3 and total LUS scores were used in the clinical assessment of patients	Quantitative LUS can be considered a reliable follow-up tool for dynamic lung monitoring in pregnant women with COVID-19 and can reduce the use of chest CT
Gil-Rodrigo et al[32], 2021	Spain	Letter to the editor	4 women at gestational weeks 6, 9, 19 and 25, 2 of them confirmed as COVID-19	Symptoms and LUS were used as initial assessment and nasopharyngeal swab RTPCR was used for confirmation	With convex transducer, 8 posterior lung areas	With regard to potential disease transmission during a pandemic, LUS in pregnant women enables safe diagnosis and early treatment. One of the limitations is the absence of standardized training, the learning curve is relatively
Inchingolo et al[33], 2020	Italy	Case report	1 pregnant woman at 23 wk gestational age	Oropharyngeal swab RT-PCR	14 regions with Convex wireless transducer (3.5 MHz)	Point-of-care LUS examination could play a key role in the assessment of pregnant women with suspected COVID-19
Kalafat E et al[34], 2020	Turkey	Case report	32-yr-old woman at 35 + 3 wk gestational age	Symptoms and lung ultrasound findings first and confirmed by nasopharyngeal RT-PCR after	Thick and bilateral B-lines in the basal posterior lungs area (during the first assessment), diffuse B-lines (2 d later)	Report of positive lung ultrasound findings consistent with COVID-19 in a pregnant woman with an initially negative RT-PCR result
Porpora et al[35], 2021	Italy	Prospective observational study	30 pregnant women at 36 wk of median gestational age (range between 28-38 wk)	Nasopharyngeal swab RT-PCR	Linear or convex probes, the LUS investigation was carried out with the 12-zone method, both in the supine and lateral positions	LUS is proven to be safe, reliable, sensitive, easily repeatable, and could be a guide to define the most appropriate strategy for improving clinical and pregnancy outcomes
Yassa et al[10], 2021	Turkey	Case series	8 Pregnant women (9-38 wk) who underwent LUS examinations after obstetric US examinations	Symptoms and LUS first and confirmed by nasopharyngeal RT-PCR testing later	Fourteen areas (3 posterior, 2 lateral, and 2 anterior) were scanned per patient for 10 seconds along the indicated lines	After an obstetric US assessment, the routine use of LUS can substantially influence the clinical treatment of pregnant women with COVID-19
Yassa et al[27], 2020	Turkey	Prospective Cohort	296 pregnant women (23 with a positive result for COVID-19) at 5 to 42 wk gestational ages (mean = 35.18 wk)	LUS first and confirmed by nasopharyngeal RT-PCR later	12 areas, with the posterior ones in the posterior axillary line	Using lung ultrasound was found more predictive in detecting the infection than the use of symptomatology solely
Youssef et al[36], 2020	Italy	Case report	1 pregnant woman, 33 yr old at 26 wk of gestational age	LUS findings were former, positive nasopharyngeal swab RTPCR confirmation later	6 regions in each hemithorax (2 anterior, 2 lateral, and 2 posterior). Linear or convex probes	We believe that extensive training of physicians may be considerably helpful in terms of the ongoing pandemic of COVID-19

COVID-19: Coronavirus disease 2019; CT: Computed tomography; LUS: Lung ultrasound; RT-PCR: Reverse transcription polymerase chain reaction; US: Ultrasound.