Comparison of breath-guards and face-masks on droplet spread in eye clinics.

INTRODUCTION: COVID-19 has impacted ophthalmic care delivery, with many units closed and several ophthalmologists catching COVID-19. Understanding droplet spread in clinical and training settings is paramount in maintaining productivity, while keeping patients and practitioners safe. OBJECTIVES: We aimed to assess the effectiveness of a breath-guard and a face mask in reducing droplet spread within an eye clinic. METHODS: We performed a randomised trial of droplet spread using a fluorescein-based cough model to assess the efficacy of a 'breath-guard' and 'face-mask' to prevent the spread of droplets. The 'cough' spray was collected on calibrated paper targets. The sheets were photographed under blue light, with an orange filter on the camera; the position and size of the spots was measured with software originally developed for astronomy. We performed 44 randomised coughs; 22 controls with no breath-guard or face-mask, 11 using breath-guard only and 11 with combined breath-guard and face-mask. We compared both the number of droplets detected and the area of drops on paper targets. RESULTS: The average number of droplets in the controls was 19,430 (SE 2691), the breath-guard group 80 (SE 19) droplets (P < 0.001); in the combined In the group the count was 5 (SE 2), a significant drop from shield only (P = 0.008). The mean areas of each target covered by spots for each group were 5.7 ± 0.857% (95% CI), 0.004 ± 0.000104% (95% CI) and 0.001 ± 0.0000627% (95% CI) respectively. CONCLUSION: These results show that the breath-guard alone reduced the droplet count by 99.93%. Combining the breath-guard with a face-mask reduced the droplet count by over 99.98%. Breath-guards are widely used in clinics and this trial demonstrates that breath-guards with face-masks effectively block droplet spray.

The use of aerosol generating procedures (AGPs) during the COVID-19 pandemic in the diagnosis of lung cancer: a narrative review.

OBJECTIVE: In this article we discuss the current evidence for these concerns and highlight where further work is required to understand the risk from these procedures and how it can be mitigated for. BACKGROUND: The COVID-19 (coronavirus-19 or SARS-CoV-2) pandemic has impacted on many aspects of patient care both for those with the virus and those with other illnesses. Of particular concern has been the risk to staff and patients from the spread of the virus in health care settings. This has led to changes in guidelines and practice in community and hospital settings that has implications on patient diagnostic pathways in lung cancer, with a specific emphasis on aerosol generating procedures (AGPs). METHODS: A literature search was carried out and 44 abstracts were initially found. Given the novel status of COVID-19, we included severe acute respiratory syndrome (SARS) and Middle East Respiratory Syndrome (MERS) in our search. Five papers were selected for further analysis. An additional paper was highlighted during our research and therefore included in our review. CONCLUSIONS: The papers selected assessed the risk of transmission during AGPs. The six articles selected assessed the risk of aerosol transmission during various AGPs (bronchoscopy, pleural procedures and pulmonary function tests) and each found that the risk of viral transmission via aerosol was low. As mentioned above, at the time the paper was written, there was a paucity of evidence regarding AGPs in the era of COVID-19. There is emerging evidence that our understanding of these procedures may be outdated and the risk of transmission maybe lower than previously anticipated. However, we need further reliable evidence to change practice going forward.

Exploring the Waveform Characteristics of Tidal Breathing Carbon Dioxide, Measured Using the N-Tidal C Device in Different Breathing Conditions (The General Breathing Record Study): Protocol for an Observational, Longitudinal Study.

BACKGROUND: In an increasingly comorbid population, there are significant challenges to diagnosing the cause of breathlessness, and once diagnosed, considerable difficulty in detecting deterioration early enough to provide effective intervention. The burden of the breathless patient on the health care economy is substantial, with asthma, chronic heart failure, and pneumonia affecting over 6 million people in the United Kingdom alone. Furthermore, these patients often have more than one contributory factor to their breathlessness symptoms, with conditions such as dysfunctional breathing pattern disorders-an under-recognized component. Current methods of diagnosing and monitoring breathless conditions can be extensive and difficult to perform. As a consequence, home monitoring is poorly complied with. In contrast, capnography (the measurement of tidal breath carbon dioxide) is performed during normal breathing. There is a need for a simple, easy-to-use, personal device that can aid in the diagnosis and monitoring of respiratory and cardiac causes of breathlessness. OBJECTIVE: The aim of this study was to explore the use of a new, handheld capnometer (called the N-Tidal C) in different conditions that cause breathlessness. We will study whether the tidal breath carbon dioxide (TBCO2) waveform, as measured by the N-Tidal C, has different characteristics in a range of respiratory and cardiac conditions. METHODS: We will perform a longitudinal, observational study of the TBCO2 waveform (capnogram) as measured by the N-Tidal C capnometer. Participants with a confirmed diagnosis of asthma, breathing pattern disorders, chronic heart failure, motor neurone disease, pneumonia, as well as volunteers with no history of lung disease will be asked to provide twice daily, 75-second TBCO2 collection via the N-Tidal C device for 6 months duration. The collated capnograms will be correlated with the underlying diagnosis and disease state (stable or exacerbation) to determine if there are different TBCO2 characteristics that can distinguish different respiratory and cardiac causes of breathlessness. RESULTS: This study's recruitment is ongoing. It is anticipated that the results will be available in late 2018. CONCLUSIONS: The General Breathing Record Study will provide an evaluation of the use of capnography as a diagnostic and home-monitoring tool for various diseases. REGISTERED REPORT IDENTIFIER: RR1-10.2196/9767.

Comparison of SPECT aerosol deposition data with twenty-four-hour clearance measurements.

Three-dimensional (3D) radionuclide imaging provides detailed information on the distribution of inhaled aerosol material within the body. Analysis of the data can provide estimates of the deposition per airway generation. Information on regional distribution of deposited aerosol can also be obtained from 24-hour clearance measurements. In this study, a nebulizer was used to deliver a radiolabeled aerosol to nine human subjects. Single photon emission computed tomography (SPECT) has been used to assess the distribution of aerosol deposition per airway generation. The deposition pattern was also estimated using measurements of the aerosol remaining in the lung 24 h after inhalation. The error in the SPECT value was assessed by simulation and that in the 24-h clearance value by repeat analysis. The mean fraction of lung deposition in the conducting airway (CADF) from SPECT was 0.21. The corresponding 24-h clearance value was 0.23. These values were not significantly different. There was a weak but non-significant correlation between the SPECT and 24-h measurements (r = 0.49). The standard error of the difference was 0.11. The corresponding errors on the SPECT and 24-h clearance measurements were 0.04 and 0.05, respectively. There was no systematic difference between the values of conducting airways deposition obtained from 24-h measurements and SPECT. However, there were random differences on individual subjects, which were larger than the estimated measurement errors.