ABSTRACT
Introduction: The difference between the end-tidal carbon dioxide (ETCO2) and arterial carbon dioxide (PaCO2) represents alveolar dead space. This is commonly characterised as the alveolar dead space fraction (AVDSf), which is calculated using the equation (PaCO2 -ETCO2)/PaCO2. The AVDSf can be easily calculated in the intensive care unit using routinely documented data. Pulmonary embolism (PE) increases dead space and so it is hypothesised that AVDSf may be a useful diagnostic tool for PE. Research in the Emergency Department setting has shown that AVDSf can help exclude PE when combined with other diagnostic tests. Patients with COVID-19 are at high risk of concurrent PE but diagnosis in invasively ventilated patients is challenging due to limitations with routine assessment, infection control issues and clinical instability. No studies have assessed the potential role of AVDSf in this diagnostic process. Objective: We sought to investigate the diagnostic utility of AVDSf prior to Computed Tomography Pulmonary Angiogram (CTPA) in invasively ventilated patients with COVID-19 and suspected PE. Methods: This was a retrospective, single-centre cohort study, delivered as a service evaluation with formal R&D approval and oversight (Ref: S20HIP17). All invasively ventilated patients with confirmed COVID-19 who underwent CTPA between March 2020 and April 2021 at a large UK intensive care unit were included. AVDSf values were derived from routine data taken at the closest available timepoint prior to the CTPA. Consultant radiologist reporting of the CTPA images was used as the reference standard for PE diagnosis. Results: 48 CTPAs were included in the final analysis. Therapeutic-dose anticoagulation was given before CTPA in 45.8% (n=22) of cases. The mean pre-CTPA PaO2/FiO2 (P/F ratio) was 134 mmHg (IQR 56.1). The 28-day mortality was 70.4%. 52.1% of CTPAs demonstrated a PE (n=25). Of these PEs, 8 were classified as central or lobar, 11 as segmental and 6 as subsegmental. The mean difference in AVDSf between PE positive CTPA and PE negative CTPA was 0.02 (0.34 vs 0.32). This difference was not statistically significant (p=0.255). At a threshold of 0.33 the sensitivity was 0.56 and specificity was 0.48. AVDSf did not provide diagnostic utility at any cut-off point (AUC=0.561). Conclusion: This study is the first to investigate the utility of AVDSf in diagnosing PE in COVID-19 patients. Our findings suggest there is no value in using single AVDSf values to guide decisions on diagnostic imaging in patients with severe COVID-19 and suspected PE. Given research has demonstrated the potential for AVDSf to reduce imaging requests in patients with a low pre-test probability of PE, further research may be appropriate in ambulatory COVID-19 patients. Additionally, the interpretation of trends in AVDSf, rather than its calculation at a single timepoint, could be investigated as a diagnostic tool for PE in critically unwell, ventilated patients.
ABSTRACT
Croydon University Hospital Remote consultations were rapidly introduced in the spring of 2020 in the neurology outpatient setting across the UK and worldwide due to the Covid-19 pandemic. Consulting remotely provides new chal-lenges to previously familiar practices. Here we present four different but commonly seen cases in a south London outpatient neurology service. With each case we address a key domain: history taking, examina-tion, the digital divide and changing the consulting environment. History taking is largely unchanged and indeed may improve the patient experience when performed in a familiar environment. The examina-tion is different and a greater understanding of which aspects of the neurological exam are and are not possible remotely continues to be discussed. The adoption of remote consultations requires patients to have a confident ability to activate and interact with technologies. The future development of technolo-gies and guidelines should proactively engage with patients of all ages and abilities to avoid biases in their development. Remote consultations are likely to continue to play a part in the future of outpatient neurology;understanding their most effective allocation and proactively developing technologies with patients will be essential for their success.
ABSTRACT
Introduction: The geographic characteristics of the otolaryngology-head and neck surgery (OHNS) residency match remain understudied and anecdotal. We present an indepth view of matching trends over 5 application cycles (2015-2020), based on regional differences within the United States. This information may serve as a context for regional trend shifts that might become evident in the current match cycle due to the COVID-19 pandemic. Method: We present a retrospective study of OHNS residency match outcomes of applicants to our single-institution from 2015 to 2020. National Resident Matching Programprovided data included medical school, match status, match program, and match year. Matches were characterized as home-program, home-region, or out-of-region. Statistics were done using Pearson chi-square testing. Results: From 2015 to 2020, 1252 US MD seniors applied to our institution, comprising 72.2% of all match participants. A total of 84.9% matched into OHNS: 18.9% to homeprograms, 35.7% to other programs in home-region, and 45.3% out-of-region. Match rates were similar for all regions (range, 83.8%-87.4%). Students from Western schools matched to home programs significantly more than students from southern or Midwest schools (27.5% vs 16.0% and 16.0%;P < .01, P < .01, respectively). The rate of home-program matching in the West increased, on average, by +6.0% per year, which was greater than any other region (range, -0.8% to 6.0%). Students from Southern schools had the most within-region matches (45.2% vs 22.6%, 32.8%, and 37.3%). Western programs matched significantly more out-of-region applicants compared with other regions (58.0%, P < .05), while Southern programs were filled by the smallest proportion of applicants from outside regions (36.9%). Conclusion: In the OHNS residency match cycles 2015- 2020, home-matching occurred in 1 in 5 cases and was more common for applicants from the Western states, while regional matching was more common among the Southern states. These trends may become more pronounced in the 2020-2021 cycle due to the rotation restrictions imposed by COVID-19.