key: cord-261062-9zhe3ejy authors: Zhu, Shu-Ting; Tao, Fang-Yi; Xu, Jing-Hong; Liao, Shu-Sheng; Shen, Chuan-Li; Shi, Bin-Bin; Liang, Zeng-Hui; Li, Qiao title: Utility of Point-of-Care Lung Ultrasound for Clinical Classification of COVID-19 date: 2020-09-21 journal: Ultrasound Med Biol DOI: 10.1016/j.ultrasmedbio.2020.09.010 sha: doc_id: 261062 cord_uid: 9zhe3ejy In this study, the utility of point-of-care lung ultrasound for the clinical classification of coronavirus disease (COVID-19) was prospectively assessed. Twenty-seven adult patients with COVID-19 underwent bedside lung ultrasonography (LUS) examinations three times within the first two weeks of admission to the isolation ward. We divided the 81 exams into three groups (i.e., moderate group, severe group, and critically ill group). Lung scores were calculated as the sum of points. A rank sum test and bivariate correlation analysis were carried out to determine the correlation between LUS on admission and the clinical classification of COVID-19. There were dramatic differences in LUS (p<0.001) among the three groups, and LUS scores (r=0.754) correlated positively with clinical severity (p<0.01). In addition, moderate, severe, and critically ill patients were more likely to have low (≤9), medium (9-15), and high scores (≥15), respectively. This study provides stratification criteria of LUS scores to assist in quantitatively evaluating COVID-19 patients. COVID-19, which is caused by severe acute respiratory syndrome corona virus 2 (SARS-CoV-2), is a 3 new public health crisis threatening the world. The disease is transmitted primarily via direct contact or through droplets generated by an infected individual when coughing or sneezing (Rothe et al. 2020 ). SARS-CoV-2 binds to angiotensin receptor 2 (ACE 2 ) expressed by cells of the lung, making the lung the primary site of damage (Singhal 2020) . The most frequent symptoms of COVID-19 pneumonia are fever, cough, and fatigue; other symptoms include sore throat, myalgia, hemoptysis, and dyspnea. These symptoms are similar to those of other respiratory infections. Interestingly, the severity of COVID-19 varies, ranging from an asymptomatic state to acute respiratory distress syndrome and multiorgan dysfunction (Huang et al. 2020 ； Ren et al. 2020 . Therefore, effective therapies warrant the specific identification of disease severity. LUS has been rapidly developed in the last few years. Although it was originally proposed for a range of clinical applications in the 1990s, the technique has spread mainly in the last decade. Currently, acute respiratory failure, circulatory failure and cardiac arrest can be assessed by LUS. LUS can also be utilized for quantitative assessment of lung aeration and may be a useful tool to guide mechanical ventilation (Mojoli et al. 2019) . Moreover, prior research has shown that LUS affected clinical decisions for up to 50% of intensive care unit patients (Xirouchaki et al. 2014) . The unique benefits of LUS in the current context include bedside feasibility, no radiation, low cost and easy application (See et al. 2018 ). Indeed, due to its ready availability at the bedside, LUS may play a pivotal role in monitoring serial changes in COVID-19 pneumonia. The current clinical evidence strongly suggests the potential diagnostic accuracy of LUS for COVID-19 (Volpicelli and Gargani 2020) . Previous studies have reported that bedside LUS correlates with CT findings in adults with COVID-19 pneumonia (Poggiali et al. 2020) . Although the latter technique is considered one of the primary imagological criteria for the diagnosis of COVID-19, the disadvantages of 4 radiographic examinations make LUS a complementary method for COVID-19 patients. Some investigators suggest that lung abnormalities in the pediatric population and pregnant women with COVID-19 can be effectively detected by radiation-free LUS (Buonsenso et al. 2020c ；Denina et al. 2020 ). In addition, ultrasound, especially the use of pocket devices, is considered relatively safer because it reduces the exposure of health care workers to infected patients . Early studies suggested that the irregular pleural line with small subpleural consolidations, white lung, confluents and irregular vertical artifacts (B-lines) are ultrasonic manifestations of COVID-19 pneumonia , and LUS scores have been used for the identification of patients with lung involvement and disease severity (Vetrugno et al. 2020) . However, such studies are mostly subject case reports, and further research is lacking. Thus, the present study was undertaken to investigate correlations between LUS and the severity of COVID-19, aiming to clarify the diagnostic and monitoring role of LUS in COVID-19 pneumonia. The prospective observational study included 27 patients with imaging signs of COVID-19 pneumonia (moderate and above) in the isolation ward of the First Affiliated Hospital of Wen Zhou Medical University from February 1 st , 2020, to March 1 st , 2020. All patients underwent three bedside LUS scans within the first two weeks of admission. We ensured that all patients were admitted in the early stages of COVID-19 because patients with confirmed COVID-19 are immediately admitted to the isolation ward in China. The interval between each ultrasound examination was three to five days. The study protocol was reviewed and approved by the Ethics Committee of the First Affiliated Hospital of Wen Zhou Medical University. The next of kin of all subjects provided informed consent for participation in this study. Exclusion criteria: (1) Patients with mild disease who lacked imaging signs of pneumonia; (2) Patients with any conditions that interfered with LUS assessment, such as obstruction on the scan area and chest deformity; (3) Patients receiving examinations fewer than three times due to a short duration of hospitalization; (4) Patients lacking clinical data. A bedside LUS was performed by a trained sonographer using a C1-5-RS transducer (1.5-5 MHz), GE Vivid iq. set (GE Healthcare, WuXi, JiangSu, China). The study depth was set to approximately 10-15 cm (depending on the body habitus). The sonographer wore the standard personal protections as per WHO indications and disinfected the probe with 3% hydrogen peroxide after the examination. Ten (2 anterior, 2 lateral, and 1 posterior) lung zones were scanned in sequence ( Figure 1 ). The anterior, lateral and posterior zones were divided by the anterior and posterior axillary lines. The anterior and lateral regions were divided into upper and lower parts, respectively, by the 4 th rib. Scanning started in the anterior zone, descending from the clavicle to the 4 th rib (zone A1) and then downwards to the upper surface of the abdominal organs (zone A2). After that, the scan proceeded down from the axilla to the 4 th rib (zone L1) and then to the upper margin of the abdominal organs (zone L2). We examined the posterior (zone P) and scanned the abdominal contents from the upper lung boundary. The contralateral thoracic cavity was then examined. The anterolateral parts of the chest wall were examined in the supine position and the posterior parts either in the lateral or seated position. This study had no impact on the treatment of the patients. The sonographic signs of lung aeration were classified into the following four scoring patterns (Soldati et al. 2020a) (Figure 2 ): (1) Score 0: the presence of lung sliding, with A lines or isolated B lines (less than 6 or equal to two) and the pleural line continuous and regular; (2) Score 1: the pleural line was indented, with multiple spaced B lines of an interval of approximately 7 mm; (3) Score 2: the pleural line was broken, with coalescent B lines at an interval of ≤3 mm; (4) Score 3: dense and largely extended white lung with or without larger consolidations. For a given region of interest, points were allocated according to the worst ultrasound score pattern observed. The lung scores were calculated as the sum of points (the highest score was 30). Statistical analysis was performed with SPSS 26.0 software (SPSS, Chicago, IL, USA). We divided the 81 exams into three groups (i.e., moderate group, severe group, and critically ill group) according to Guidelines on Diagnosis and Treatment of Novel Coronavirus Pneumonia (Trial, seventh edition) at each examination (Table 1) . Clinical data, including the LUS score, blood biochemistry (alanine aminotransferase, aspartate aminotransferase, r-glutamyl transferase, creatinine, and blood urea nitrogen), routine blood examinations (leukocyte count and lymphocyte count), and blood coagulation function (D-dimer), were monitored synchronously. The distribution of LUS scores among the three groups is provided. In addition, categorical variables with p<0.05 according to the Spearman test were analyzed. Such categorical variables are expressed as percentages, and results were compared with those of the Kruskal-Wallis test or Wilcoxon test, as appropriate. A p-value less than 0.05 was considered statistically significant. Of the 27 patients with COVID-19 enrolled in our study, 16 (59%) were male and 11 (41%) female, with an average age of 63.0 ± 14.2 years (range, 35-93 years). The distribution of LUS scores for the three 7 COVID-19 groups is summarized in Figure 3 . Thirty-five exams (43%) were classified into the moderate group, 20 (25%) into the severe group, and 26 (32%) into the critically ill group. The mean LUS scores of the critically ill, severe and moderate groups were 16.2±2.4 (range, 11-20), 12.9 ± 3.7 (range, 7-20), and 7. 8±3.7 (range, 11-20) , respectively. According to Spearman correlation test results (Table 2) Then, we divided the LUS scores into three scales (low ≤9; 9