Characterizing the Blood Pressure Response to Physical Counterpressure Manoeuvres Using Surface Electromyography in Adults With Long Covid

Orthostatic intolerance (OI) is common in Long Covid. Physical counterpressure manoeuvres (PCM) may improve OI in other disorders. We characterised the blood pressure-rising effect of PCM using surface electromyography (sEMG) and investigated its association with fatigue in adults with Long Covid. Participants performed an active stand with beat-to-beat hemodynamic monitoring and sEMG of both thighs, including PCM at 3-minutes post-stand. Multivariable linear regression investigated the association between change in systolic blood pressure (SBP) and change in normalised root mean square (RMS) of sEMG amplitude, controlling for confounders including the Chalder Fatigue Scale (CFQ). In 90 participants (mean age 46), mean SBP rise with PCM was 13.7 (SD 9.0) mmHg. In regression, SBP change was significantly, directly associated with change in RMS sEMG ( 0.25 , 95% CI 0.07-0.43, P = 0.007);however, CFQ was not significant. PCM measured by sEMG augmented SBP without the influence of fatigue. Copyright © 2013 IEEE.

FATIGUE EXPERIENCED BY ADULTS WITH LONG-COVID WAS NOT ASSOCIATED WITH AN EMG-DERIVED MUSCLE FATIGUE INDEX

Background: One of the most prominent challenges of the COVID-19 pandemic is the emergence of the post-COVID-19 syndrome or ‘long-COVID’ following the acute phase of the viral infection. With a plethora of debilitating symptoms across many physiological systems, the pathophysiology of long-COVID remains elusive and subject of intense research efforts. Adults with long COVID are often affected by prolonged fatigue, which could be linked to neuromuscular function impairment. We hypothesised that there might be a correlation between subjective fatigue and an Electromyograph(EMG)-derived muscle fatigue index in adults with long-COVID. Methods: As part of a neuro-cardiovascular instability assessment protocol, participants were asked to squeeze the thigh muscles as hard as possible for ten seconds during both supine resting and after active and passive standing (head-up tilt) tests. Surface EMG was used to capture on each leg the physiological activity of the vastus lateralis and rectus femoris during the squeezes, from which the muscle fatigue index was computed based on both the mean and median frequencies of each 10-second maximum prompted muscle contraction. Using two-sided Spearman correlation coefficients, we examined the associations between the muscle fatigue indices and self-reported fatigue measured by the Chalder Fatigue Scale (CFQ). Results: 108 participants were included, 77 female and 31 male, with a mean age of 46 (range 25-78) years, 22% of whom were hospitalised in the acute phase of SARS-CoV-2 infection. Strong intercorrelations were found between the muscle fatigue indices derived from the mean and median frequencies of thigh muscle contractions. However, no significant correlations were detected between the muscle fatigue indices and CFQ scores. Conclusion: Self-reported fatigue as measured by the CFQ was not associated with an EMG-derived muscle fatigue index in this long-COVID cohort.

Suspected Neonatal COVID-19 Infection in an Extremely Premature Infant

Introduction: The COVID-19 pandemic has been widely described, however, there is limited data regarding neonatal infection. We present an extremely premature neonate with suspected COVID-19 pneumonia treated with Remdesivir. Case Description: Our patient is an infant born via emergency cesarean section for chorioamnionitis at 24 weeks gestational age with extremely low birth weight (ELBW). Mother is a 23-yearold primigravid female whose pregnancy was complicated by asymptomatic COVID-19 infection diagnosed by nasopharyngeal PCR ten days prior to delivery. Antenatal steroids were given for imminent premature delivery. Infant was intubated during initial resuscitation then extubated to non-invasive positive pressure ventilation (NIPPV) on day three of life. On day seven of life, she developed increasing apneic spells and feeding intolerance. Empiric antibiotics were initiated while awaiting blood and cerebrospinal fluid cultures. Blood culture grew Serratia marcescens and antibiotic coverage was tailored to cefepime monotherapy. Our patient remained stable on non-invasive respiratory support seven days into her sepsis event. Around this time, histopathological analysis of the placenta revealed acute villitis and intervillositis highly suggestive of COVID-19 placentitis. A positive nasopharyngeal COVID-19 PCR was noted on day ten of life. Our patient remained stable on non-invasive respiratory support until day fourteen of life, when she suddenly developed refractory hypoxemia requiring intubation. This coincided with acute changes in her chest x-ray (Fig 1). The negative bacterial respiratory culture, timing of clinical deterioration, and placental findings increased our suspicion for symptomatic co-infection with COVID-19. Patient continued to have refractory hypoxia and poor ventilation despite maximum settings and inhaled nitric oxide. After an extensive multidisciplinary discussion, patient received Remdesivir as a compassionate measure. Neonatal dosage was well tolerated with no adverse effects at 5 mg/kg loading dose followed by four days of maintenance dosing at 2.5 mg/kg. Significant clinical improvement was noted after the second day by decreasing FiO2 requirements. COVID-19 PCR remained positive ten days after Remdesivir treatment was completed. Patient was extubated to NIPPV on day thirty-six of life and is currently requiring no respiratory support at 37 weeks corrected age. Discussion: We present an ELBW neonate with placental findings typical of COVID-19 infection and refractory hypoxemia likely due to COVID-19 pneumonia. To date, the mechanism for this infant's infection is unclear. Based on the Acharya et al. Classification for Maternal-Fetal-Neonatal SARS-CoV-2 infection, our patient fits into probable neonatal infection acquired post-partum category. We have strong evidence of infection but lack of absolute proof to confirm congenital disease as no testing was done at birth. We acknowledge that part of the clinical course was complicated by sepsis, however, the peak of illness correlates with the typical clinical course for COVID-19 infection. Conclusion: To our knowledge, this may be the youngest patient documented to have COVID-19 pneumonia and received Remdesivir treatment.

Acute-phase bed-rest duration was associated with lower grip strength in a post-covid-19 cohort

Background: Though age-related muscle loss is traditionally associated with older cohorts, strong evidence suggests a life-spanning precipitation of decreasing muscle mass and strength beginning as early as the fourth decade of life, with established deleterious consequences for later-life morbidity and mortality. Periods of low activity and bed rest (LA/BR) can further compound this depletion of muscle strength. Our aim was to examine such associations in a post-COVID-19 cohort. Methods: Participants reporting ongoing symptomatology and fatigue post COVID-19 underwent assessments of grip strength via hand-held dynamometry (2 measures on each hand). Demographics of COVID-19 illness, including time since diagnosis, duration of LA/BR during acute illness, and levels of fatigue were captured via self-reported questionnaires. Independent predictors of mean grip strength were investigated using a linear regression model. Results: Forty-nine participants underwent assessments (69% female, mean age 44(12) years). At the time of assessment, days post COVID-19 diagnosis ranged from 39-522 (mean 262(140)). The mean self-reported period of LA/BR during the acute illness was 15(18) days. In general, participants reported significant levels of fatigue (median Chalder Fatigue Scale score 22(8)). Mean grip strength was 41.3(6.3) Kg for men and 22.8(6.7) Kg for women. When predictors of grip strength were investigated, an increased duration of LA/BR was found to be associated with lower grip strength, independently of age, gender, time since COVID-19 diagnosis, and self-reported fatigue (Beta=-0.158, 95% Confidence Interval-0.242 to -0.074, p=0.001). Conclusion: In this cohort, every day of LA/BR during acute COVID-19 illness was independently associated with subsequent lower grip strength of approximately 150 g. These results underscore the importance of early mobilization and discouraging bed rest in the acute phase of COVID-19. Patients who are isolating should be encouraged to maintain physical activity and muscle strength as part of a modified isolation-friendly rehabilitation programme.