Electrodiagnostic findings in patients with non-COVID-19- and COVID-19-related acute respiratory distress syndrome.

BACKGROUND: Critical illness polyneuropathy and myopathy (CIPNM) is a frequent neurological manifestation in patients with acute respiratory distress syndrome (ARDS) from coronavirus disease 2019 (COVID-19) infection. CIPNM diagnosis is usually limited to clinical evaluation. We compared patients with ARDS from COVID-19 and other aetiologies, in whom a neurophysiological evaluation for the detection of CIPNM was performed. The aim was to determine if there were any differences between these two groups in frequency of CINPM and outcome at discharge from the intensive care unit (ICU). MATERIALS AND METHODS: This was a single-centre retrospective study performed on mechanically ventilated patients consecutively admitted (January 2016-June 2020) to the ICU of Careggi Hospital, Florence, Italy, with ARDS of different aetiologies. Neurophysiological evaluation was performed on patients with stable ventilation parameters, but marked widespread hyposthenia (Medical Research Council score <48). Creatine phosphokinase (CPK), lactic dehydrogenase (LDH) and mean morning glycaemic values were collected. RESULTS: From a total of 148 patients, 23 with COVID-19 infection and 21 with ARDS due to other aetiologies, underwent electroneurography/electromyography (ENG/EMG) recording. Incidence of CIPNM was similar in the two groups, 65% (15 of 23) in COVID-19 patients and 71% (15 of 21) in patients affected by ARDS of other aetiologies. At ICU discharge, subjects with CIPNM more frequently required ventilatory support, regardless the aetiology of ARDS. CONCLUSION: ENG/EMG represents a useful tool in the identification of the neuromuscular causes underlying ventilator wean failure and patient stratification. A high incidence of CIPNM, with a similar percentage, has been observed in ARDS patients of all aetiologies.

Proposal of a new criterion for electrodiagnosis of meralgia paresthetica by evoked potentials.

We examined 19 subjects with meralgia paresthetica (bilateral in three cases), recording bilateral somatosensory-evoked potentials (SSEPs) after stimulation of the tibial posterior nerve (TPN) and cutaneous stimulation in the region of the lateral femoral cutaneous nerve (LFCN). We calculated the difference between TPN SSEPs and LFCN SSEPs cortical potentials, identifying a temporal parameter that we termed D(SEP). We defined D(SEP) normal values in a control group. D(SEP) evaluation showed good sensitivity and specificity (85.7% and 82.4%, respectively; accuracy, 83.3%) in discriminating affected limbs from unaffected. The main advantage of this method is to disengage from the necessity of contralateral comparison of LFCN recordings, joined with a reduction of interindividual variability of LFCN SSEPs amplitude and latency that often causes a lower sensitivity of other methods. As an interesting consideration, D(SEP) evaluation appears to mark out a possible subclinical involvement of LFCN in the asymptomatic side of patients with meralgia paresthetica.