Bedside wireless lung ultrasound for the evaluation of COVID-19 lung injury in senior nursing home residents

Abstract

Lung Ultrasound (LUS) may be useful to diagnose presence of lung injury in older adults living in nursing homes with suspected COVID-19 pneumonia. We aimed at evaluating presence lung injury among senior nursing home residents by LUS performed with portable wireless scanner echography. The study population consisted of 150 residents with a mean age of 88 years (85% female) residing in 12 nursing homes in Northern Italy. Subjects had to have a history of recent onset of symptoms compatible with COVID-19 pneumonia or have been exposed to the contagion of patients carrying the disease. COVID-19 testing was performed with SARS-CoV-2 nasal-pharyngeal (NP) swabs. Positive subjects to LUS scanning were considered those with non-coascelent B-lines in >3 zones, coalescent B-lines in >3 zones and with iperdensed patchy non-consolidated lungs. Sixty-three percent had positive NP testing and 65% had LUS signs of pulmonary injury. LUS had a sensitivity of 79% in predicting positive NP testing. Sixteen percent of residents tested negative for SARS-CoV-2 carried the signs of COVID-19 lung injury at LUS. There were 92 patients (61%) with current or recent symptoms. Positivity to LUS scanning was reported in 73% of residents with symptoms, while it was 53% in those without (P=0.016). A positive NP testing was observed in 66% of residents with symptoms and in 57% of those without (P=0.27). We conclude that assessment of LUS by portable wireless scanner echography can be profitability utilized to diagnose lung injury among senior nursing home residents with or without symptoms compatible with COVID-19 pneumonia. Introduction The SARS-CoV-2 pandemic is impacting the global population and community transmission had led to an overwhelming number of critically-ill patients [1]. Most of patients who are suffering from the COVID-19 disease exhibit signs of pulmonary injury that are evident from clinical as well as instrumental findings [2]. Studies have shown that COVID-19 lung disease causes worse outcomes and higher mortality in older patients, especially in those with co-morbidities, such as hypertension, heart disease, diabetes, chronic respiratory disease, and chronic kidney disease [3-6]. This may be especially harmful in the elderly population living in nursing homes for their baseline co-morbidities and exposures resulting from their congregate settings [7]. Lung ultrasound (LUS) is a noninvasive tool for the evaluation of lung disease and has the advantage of rapidity, repeatability and reproducibility. Therefore, it is increasingly used by physicians at bedside to complement the findings of physical examination [8,9]. With the introduction of portable echo wireless transthoracic scanners, LUS may become a valuable tool to investigate presence of pulmonary injury in the community, especially in patients living nursing home facilities, due to their frailty and pandemic vulnerability. These considerations have led us to design a study aiming at evaluating presence lung injury among senior nursing home residents by LUS performed by portable wireless scanner echography.

Methods

The study population consisted of consecutive subjects residing in nursing homes. Inclusion criteria Abstract Lung Ultrasound (LUS) may be useful to diagnose presence of lung injury in older adults living in nursing homes with suspected COVID-19 pneumonia. We aimed at evaluating presence lung injury among senior nursing home residents by LUS performed with portable wireless scanner echography. The study population consisted of 150 residents with a mean age of 88 years (85% female) residing in 12 nursing homes in Northern Italy. Subjects had to have a history of recent onset of symptoms compatible with COVID-19 pneumonia or have been exposed to the contagion of patients carrying the disease. COVID-19 testing was performed with SARS-CoV-2 nasal-pharyngeal (NP) swabs. Positive subjects to LUS scanning were considered those with non-coascelent B-lines in >3 zones, coalescent B-lines in >3 zones and with iperdensed patchy non-consolidated lungs. Sixty-three percent had positive NP testing and 65% had LUS signs of pulmonary injury. LUS had a sensitivity of 79% in predicting positive NP testing. Sixteen percent of residents tested negative for SARS-CoV-2 carried the signs of COVID-19 lung injury at LUS. There were 92 patients (61%) with current or recent symptoms. Positivity to LUS scanning was reported in 73% of residents with symptoms, while it was 53% in those without (P=0.016). A positive NP testing was observed in 66% of residents with symptoms and in 57% of those without (P=0.27). We conclude that assessment of LUS by portable wireless scanner echography can be profitability utilized to diagnose lung injury among senior nursing home residents with or without symptoms compatible with COVID-19 pneumonia.

Introduction

The SARS-CoV-2 pandemic is impacting the global population and community transmission had led to an overwhelming number of critically-ill patients [1]. Most of patients who are suffering from the COVID-19 disease exhibit signs of pulmonary injury that are evident from clinical as well as instrumental findings [2]. Studies have shown that COVID-19 lung disease causes worse outcomes and higher mortality in older patients, especially in those with co-morbidities, such as hypertension, heart disease, diabetes, chronic respiratory disease, and chronic kidney disease [3-6]. This may be especially harmful in the elderly population living in nursing homes for their baseline co-morbidities and exposures resulting from their congregate settings [7]. Lung ultrasound (LUS) is a noninvasive tool for the evaluation of lung disease and has the advantage of rapidity, repeatability and reproducibility. Therefore, it is increasingly used by physicians at bedside to complement the findings of physical examination [8,9]. With the introduction of portable echo wireless transthoracic scanners, LUS may become a valuable tool to investigate presence of pulmonary injury in the community, especially in patients living nursing home facilities, due to their frailty and pandemic vulnerability. These considerations have led us to design a study aiming at evaluating presence lung injury among senior nursing home residents by LUS performed by portable wireless scanner echography. Methods The study population consisted of consecutive subjects residing in nursing homes. Inclusion criteria were: patients institutionalized in residential age care facilities of Pavia province in Italy with a history of recent respiratory symptoms and/or fever or have been in contact with patients that have been previously tested positive to SARS-CoV-2 infection. Exclusion criteria included asymptomatic residents of nursing homes that were not exposed to the infection. LUS was performed with a portable sector convex/linear wireless CERBERO (ATL, Milano, Italy) probes of 3.5 MHz and 7.5- 10 MHz with no harmonic filter, connected with a tablet. Focus was placed on the pleural line, maximum depth was at 8-10 cm. Mechanical index started from 0.7 cm and was reduced as further as possible. All devices were wrapped in single use plastic covers to reduce the risk of contamination and to facilitate the sterilization procedures. Patients were examined in supine or semi-recumbent position. Each hemithorax was divided by the anterior axillary line and posterior axillary line into three areas: anterior, lateral and posterior. Each of these zones was subsequently divided into upper and lower zones. The thorax was scanned in eight to twelve intercostal zones (four to six on each emithorax) depending on patient’s condition. Pleural line, presence of pleural effusion and lung sliding were also assessed. We used a 4-level scoring system [9] to establish the severity of the patient’s condition. Positive patients to LUS scanning were considered those with non-coascelent B-lines in >3 zones (score 1), coalescent B-lines in >3 zones (score 2) and with iperdensed non-consolidated state (score 3). A-lines or nonsignificant B-lines were classified as normal pattern (score 0). COVID-19 testing was performed with SARS-CoV-2 nasalpharyngeal swabs (Universal Transport Medium, Copan Diagnostics, Inc., CA, USA) [10]. Statistical analyses were performed with 25.0 SPSS Package (IBM Corp., Armonk, NY, USA). Data were expressed as mean value ± standard deviation or interquartile ranges (IQR) for continuous variables and percentages for categorical variables. Anderson-Darling test was performed to verify normality of distributions. Comparisons were made using Student’s t-test and MannWhitney test. Chi-square test was utilized to compare categorical variables. Statistically significant differences were placed at P=0.05. With positive testing for SARS-CoV-2 as reference standard, sensitivity, specificity, positive predictive value (PPV) and negative predicted value (NPV) of signs of lung injury at LUS, symptoms and oxygen saturation were evaluated. Cohen’s kappa was calculated to measure the agreement levels between LUS and NP swab in the total group and in the two different subgroups. According with Landis and Koch interpretation [11], the following ranges of kappa values were considered: <0: no agreement; 0.0- 0.2: slight agreement; 0.21-0.40: fair agreement; 0.41-0.60: moderate agreement; 0.61-0.80: substantial agreement; 0.81–1.0: perfect agreement.

Results

The study population included 150 residents of 12 nursing home facilities of the province of Pavia (Lombardy; Italy) enrolled between April 2020 and May 2020. Mean age was 88 years (range: 72-106 years; 85% female). Co-occurring diseases were present in almost all patients. History of hypertension was present in 61%, history of kidney disease in 23%, coronary artery disease in 17%, other heart diseases in 27%, cerebrovascular disease in 29%, atrial fibrillation in 19%, diabetes in 19%, heart failure in 8% and chronic respiratory disease in 9%. Current or recent symptoms, from moderate to severe, including fever, respiratory symptoms (like cough and dyspnoea), and asthenia were reported in 61%. Ninety-eight (65%) of patients had positive LUS findings. Among them, score 1 was reported in 36 patients, 32 were classified as score 2. Score 3 was observed in 30. LUS showed pleural line abnormalities in 90% of patients, most of them were irregular and discontinued and sometimes fragmented. Sliding was preserved in all but two cases. Signs of pleural effusion were reported in 11 cases. Positivity to LUS scanning was reported in 67 patients (73%) with symptoms, while it was 53% (n=31) in those without (P=0.016). Nasal-pharyngeal swabs for laboratory testing of SARS-CoV2 were collected in all study patients within a week from LUS assessment. Sixty-three of them (n=94) resulted positive for SARS-CoV-2 infection. The positive rate of COVID-19 nasalpharyngeal sampling was 66% (n=61) in patients with symptoms and 57% (n=33) in those without (P=0.27). Table 1 summarizes the characteristics of the study patients among those presenting symptoms and/or fever and in those who were asymptomatic. Figure 1 shows percentages with score 1, score 2, and score 3 lung injury at LUS among patients with symptoms and those without symptoms. In patients tested negative, 16% had positive LUS. Table 2 shows sensitivity, specificity, PPV and NPV of LUS abnormalities, symptoms and oxygen saturation in predicting positive laboratory testing of SARS-CoV-2 at nasal pharyngeal swabs. Signs of lung injury at LUS predicted positive laboratory testing with a sensitivity of 79% and a specificity of 57%. Table 3 shows sensitivity, specificity, PPV and NPV of LUS, and oxygen saturation in predicting positivity of COVID-19 nasal-pharyngeal swabs in older residents with symptoms and in those without symptoms. As far as Cohen’s kappa measures of the agreement between LUS and SARS-CoV-2 nasal-pharyngeal swabs is concerned, the coefficient was 0.36 in the total group, 0.34 in patients with symptoms and 0.37 in those who were asymptomatic.

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Bedside wireless lung ultrasound for the evaluation of COVID-19

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