Phrenic nerve conduction study in patients after Covid-19

<bold>Objectives:</bold> Since the outbreak of COVID-19 patients report from ongoing respiratory symptoms and dyspnea even after mild course of disease. As respiratory manifestations are dominant in this patient collective, prior studies were able to show neurologic and muscular manifestations as well. In regard of recent studies examining impairment of the diaphragm, the aim of this observational study was to assess potential impairment of the phrenic nerve. <bold>Methods:</bold> 75 patients admitted to pulmonary rehabilitation after COVID-19 diagnosis agreed to undergo nerve conduction study of the phrenic nerve. Prior to the examination all patients completed lung function test at the rehabilitation center and a questionnaire. Respiratory symptoms were categorized with the American Thoracic Society scale for dyspnea. <fig><object-id>erj;64/suppl_68/PA527/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig> <bold>Results:</bold> Full data record has been collected for 68 patients (18 male, 50 female). 48,5% presented decreased compound muscle action potential (CMAP) with normal latency and normal CMAP configuration. One patient showed prolonged latency with decreased phrenic nerve amplitude proposing phrenic nerve neuropathy after COVID-19 infection. <bold>Discussion:</bold> This data suggests that decreased phrenic nerve amplitude is a frequent finding in post-COVID-19 patients. In context with previous studies we conclude that reduced phrenic nerve amplitude might be an indicator for myopathic changes of the diaphragm itself.