key: cord-0985237-y9v5dsew
authors: Veronese, Nicola; Sbrogiò, Luca Gino; Valle, Roberto; Marin, Laura; Fiore, Elena Boscolo; Tiozzo, Andrea
title: PROGNOSTIC VALUE OF LUNG ULTRASOUND IN OLDER NURSING HOME RESIDENTS AFFECTED BY COVID-19
date: 2020-07-29
journal: J Am Med Dir Assoc
DOI: 10.1016/j.jamda.2020.07.034
sha: 5e19089884129ea15f12fab52b1b52bfd4c9b587
doc_id: 985237
cord_uid: y9v5dsew

ABSTRACT Objectives Lung ultrasound (LUS) imaging may play an important role in the management of patients with COVID-19–associated lung injury, particularly in some special populations. However data regarding the prognostic role of the LUS in nursing home residents, one of the most affected populations by COVID-19, are not still available. Design Retrospective. Settings and participants Nursing home residents, affected by COVID-19, were followed-up with a LUS from 08th April to 14th May 2020 in Chioggia, Venice. Methods COVID-19 was diagnosed through a nasopharyngeal swab. LUS results were scored using a 12-zone method. For each of the 12 zones (two posterior, two anterior, two lateral), the possible score ranged from 0 to 3 (1= presence of B lines separated, < 50% of space from the pleural line; 2= presence of B lines separated, > 50% of space from the pleural line; 3= lung thickening with tissue-like aspect). The total score ranged from 0 to 36. Mortality was assessed using administrative data. Data regarding accuracy (and related parameters) were reported. Results Over 175 nursing home residents, 48 (mean age: 84.1 years; mainly females) were affected by COVID-19. Twelve died during the follow-up period. The mean LUS score was 3. The area under the curve of LUS in predicting mortality was 0.603 (95% confidence intervals: 0.419-0.787) and increase to 0.725 (95% CIs: 0.41-0.99) after including follow-up LUS controls. Taking a LUS score > 4 as exposure variable and mortality as outcome, the sensitivity was 58.33%, specificity 63.89%, a positive likelihood ratio of 1.62 and a negative of 0.65. Conclusions and implications LUS is able to significantly predict mortality in nursing home residents affected by COVID-19, suggesting that this simple tool can be routinely used in this setting instead of more invasive techniques available only in hospital.

Brief summary: We report for the first time the use of lung ultrasound in nursing home showing its accuracy in predicting mortality, introducing the application of this tool also for this special population. 29 Lung ultrasound (LUS) evaluation might inform clinical decision-making for patients affected by 30 Coronavirus disease-2019 , in particular the management of the associated respiratory 31 failure and lung injury that are common in these patients, even when they are asymptomatic. 1 32 33 LUS is a practical and easy-to-perform procedure, being non-invasive, radiation-free, and portable. 34 Therefore, LUS might be used for several scenarios, including the initial bedside screening of low-35 risk patients, the diagnosis of suspected cases in the emergency room setting, the prognostic 36 stratification, and the monitoring of the changes in pneumonia during therapy. 2 For all these 37 characteristics, LUS seems to be the ideal tool for some special populations, e.g. pregnant women 38 and children. 3 Given this background, LUS could be an ideal tool for the early identification of 39 COVID-19 pneumonia in people affected by dementia, highly disabled and/or bedridden, such as Despite this background, to the best of our knowledge, data regarding the prognostic role of the 45 LUS in nursing home residents are not still available. Therefore, with this research, we aimed to 46 investigate the prognostic role of LUS in predicting mortality in a large nursing home placed in 47 Participants 50 The nursing home "Felice Fortunato Casson" is placed in Chioggia, placed at about 40 Km from 51 Venice, Italy. The nursing home can host a maximum of 175 residents. On March, 29 th in response 52 to increased local awareness of COVID-19 in nursing homes, the Veneto Region indicated 53 periodical screening assessments with portable serological tests or nasopharyngeal swabs, every 10 54 days. After the first case diagnosed in our nursing home on 29 th March, 2020, the local Emergency 55 Department (ED) chief (AT) followed the residents with periodical LUS and clinical assessments 56 (two days in a week). The period of which study referred was from 08 th April to 14 th May 2020. Briefly, the histopathologic appearance of initial COVID 19 pneumonia is characterized by 71 alveolar damage, while the inflammatory component is patchy and mild. 6 Reparative processes with 72 pneumocyte hyperplasia and interstitial thickening may sometimes occur. 6 The advanced phases 73 report gravitational consolidations with the presence of hemorrhagic necrosis, alveolar congestion, edema, flaking, and fibrosis. 6 These pathological findings can give specific lung patterns at the LUS 75 that highly correlate with histopathologic findings. 7 76 LUS examination was made according to standard procedures, with the appropriate protections 77 worn by the operators. 8 LUS is normally performed in supine patients. 8 LUS was already used in 78 other works related to COVID-19 research, using a 12-zone method: two zones for the anterior 79 vision, two for lateral, two for posterior, for both left and right lungs. 1 For each zone, the possible 80 score may range from 0 to 3: 0=normal pattern; 1= presence of B lines separated with less than 50% 81 of space from the pleural line (with or without thickening); 2= presence of B lines separated with 82 more than 50% of space from the pleural line (with or without thickening); 3= lung thickening with 83 tissue-like aspect. The presence of pleural effusion was also evaluated and reported in the diagnosis.

The obtained score may range from 0 to 36. Only one operator (AT) made all the exams. Moreover, with 95% CIs (confidence intervals). We also reported the data regarding sensitivity, specificity, 96 positive and negative likelihood ratios of the for all the cut-off points identified by the LUS score.

In order to decide the best point in terms of accuracy, the Youden's index 9 (i.e. the sum of 98 sensitivity and specificity less 1) was calculated. We also adjusted the area under the curve using 99 the values of the follow-up tests, where available.

Threshold of statistical significance was set to 5%. All statistical analyses were performed with 101 STATA software version 14.1 (Stata Corp LP, College station, Texas).

Among the 175 residents of the nursing home in Chioggia, 50 (=28.6%) were affected by COVID-104 19 diagnosis. Of them, for two residents data regarding LUS were not available. Therefore, 48 105 residents affected by COVID-19 were finally included in this research.

The 48 nursing home residents aged a mean of 84.1±9.8 years (range: 56-101 years), mainly 108 females (=81.3%). Briefly, these residents were mainly affected by dementia and were bedridden.

Of them, 12 residents died during follow-up period, with a lethality rate of 25%.

The mean LUS score was 3 (range: 0-11). Figure 1 shows the area under the curve, taking LUS 112 score as exposure and mortality as outcome. The AUC was 0.603 (95% CIs: 0.419-0.787) and, after 113 adding the follow-up LUS controls, was 0.725 (95% CIs: 0.41-0.99). In Table 1 , we reported the 114 values of some accuracy parameters of LUS score in predicting mortality. Among all the scores 115 considered, the best was a score > 4 for which the sensitivity in predicting mortality was 58.33%, 116 specificity 63.89%, the positive likelihood ratio 1.62 and the negative 0.65. However, we did not 117 find any significant difference in mortality risk in residents with a LUS score > 4 vs. < 4 in 118 predicting mortality (7/20 vs. 5/28; Chi-square test, Fisher exact test=0.28).

We run a similar analysis, taking, as exposure, the oxygen saturation at the time of the LUS. This 121 parameter ranged from 88 to 98%. In this case the AUC was 0.501 (95% CIs: 0.382-0.699), 122 indicating that oxygen saturation is poorly indicative of mortality in this cohort.

In this study, including 48 nursing home older residents affected by COVID-19 we found that LUS 125 is good and fairly accurate tool in predicting mortality, indicating that ultrasound examination can 126 be used in this special population, often characterized by dementia and sudden death and, 127 consequently, difficult to transport in hospital. To the best of our knowledge this is the first report in 128 this population that seems suffer, more than other populations, of the COVID-19 epidemic. substantially confirmed that LUS has a good agreement with the hystophatological findings typical 135 of COVID-19 pneumonia and therefore with other radiographic tools. 1,11,12 However, our study has 136 two novel aspects that we would like to discuss.

In another research, some Italian authors reported that 67% had abnormal LUS findings, with the 139 most common patterns represented by multiple sub-pleural consolidations and diffuse B-lines, often 140 bilateral. Therefore, a diagnosis of suspect COVID-19 pneumonia was made in half of the patients.

However, our study was the first trying to associate LUS examination with mortality, therefore 142 suggesting a potential prognostic role for this tool. In this regard, we believe that our findings are of 143 importance since they further confirm the reliability of LUS in COVID-19, particularly if frequently 144 repeated during follow-up period. If we compared our data regarding LUS to the oxygen saturation, 145 we observed that LUS is more accurate than oxygen saturation and this fact, in our opinion, 146 probably reflects the course of COVID-19 pneumonia that often can start as mild/moderate 147 pneumonia with precipitous clinical drops, often requiring intubation and leading to death. 13 The 148 second novel aspect is that our work may open the possibility to use LUS not only in hospital, but also at home and in nursing home. We would like to remember that in Italy several patients affected 150 by COVID-19 were and are treated at their homes. 14 Consequently, to have a portable device that is 151 easily able to give the diagnosis and the severity of pneumonia of COVID-19 could be of 152 importance in the next future, for treating patients affected by this condition without hospitalization.

The findings of our study must be interpreted within its limitations. First, the sample size included 155 was small and future larger studies are needed to confirm these findings. Second, our investigation 156 did not consider other negative (e.g. the presence of comorbidities and poly-pharmacology) or 157 positive (e.g. the use of therapy against COVID-19) factors in the association between LUS score 158 and mortality. Finally, our study should be considered exploratory since the area under the curve 159 was less than 0.70 (a common cut-off for considering a tool having a clinical value) and that the 160 values for sensitivity/specificity for a score > 4 are probably too low for definitively indicating LUS 161 as screening tool for people affected by COVID-19. 

LUS is able to significantly predict mortality in nursing home residents affected by 165 suggesting that this simple tool can be routinely used in this setting instead of more invasive 166 techniques available only in hospital. Future larger studies are needed to confirm our findings. In bold, the values of the lung ultrasound score > 4, since it is the most predictive in mortality among all the cut-off points considered, based on Youden's index.

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