Hélène Prigent

Background: Viral respiratory tract infections (VRTIs) are among the most common diseases, but the risks of superinfection for different virus species have never been compared. Methods: Multicenter retrospective study conducted among adults who tested positive for VRTIs with reverse-transcription polymerase chain reaction. We compared characteristics between influenza (A or B) and paramyxoviruses (respiratory syncytial virus, parainfluenza virus types 1 and 3, and human metapneumovirus) and identified predictors of superinfection and hospitalization.s Results: Five hundred ninety patients had VRTI, including 347 (59%) influenza and 243 paramyxovirus infections with comparable rates of superinfections (53% vs 60%). In multivariate analyses, the predictors of superinfections were age >75 years (adjusted odds ratio, 2.37 [95% confidence interval, 1.65–3.40]), chronic respiratory disease (1.79 [1.20–2.67]), and biological abnormalities, including neutrophil count >7000/µL (1.98 [1.34–2.91)], eosinophil count 0.25ng/mL (2.8 [1.65–4.73]). The predictors of hospitalization were age >75 years old (adjusted odds ratio, 3.49 [95% confidence interval, 2.17–5.63]), paramyxovirus infection (2.28 [1.39–3.75]), long-term use of inhaled corticosteroids (2.49 [1.13–5.49]), and biological abnormalities, including neutrophil count >7000/µL (2.38 [1.37–4.12)] and procalcitonin level >0.25ng/mL (2.49 [1.23–5.02]). Kaplan-Meier survival curves showed that influenza-infected patients had a higher mortality rate than those with paramyxovirus infections (8.9% vs 4.5%, respectively; P = .02). Conclusions: Our study revealed a high rate of superinfection (56%), not related to viral species. However influenza virus was associated with a poorer prognosis than paramyxoviruses, pleading for a broader and large-scale vaccination of individual at risk of VRTIs.

Respiratory involvement in neuromuscular disorders may contribute to impaired breathing-swallowing interactions, swallowing disorders and malnutrition. We investigated whether the use of non-invasive ventilation (NIV) controlled by the patient could improve swallowing performances in a population of neuromuscular patients requiring daytime NIV. Ten neuromuscular patients with severe respiratory failure requiring extensive NIV use were studied while swallowing without and with NIV (while ventilated with a modified ventilator allowing the patient to withhold ventilation as desired). Breathing-swallowing interactions were investigated by chin electromyography, cervical piezoelectric sensor, nasal flow recording and inductive plethysmography. Two water-bolus sizes (5 and 10ml) and a textured yogurt bolus were tested in a random order. NIV use significantly improved swallowing fragmentation (defined as the number of respiratory interruption of the swallowing of a single bolus) (p = 0.003) and breathing-swallowing synchronization (with a significant increase of swallows followed by an expiration) (p <0.0001). Patient exhibited piecemeal swallowing which was not influenced by NIV use (p = 0.07). NIV use also significantly reduced dyspnea during swallowing (p = 0.04) while preserving swallowing comfort, regardless of bolus type. The use of patient controlled NIV improves swallowing parameters in patients with severe neuromuscular respiratory failure requiring daytime NIV, without impairing swallowing comfort. ClinicalTrials.gov NCT01519388

Introduction: Myotonic dystrophy type 1 (DM1) is an autosomal dominant disease caused by CTG repeats in the myotonin-protein kinase. Transcribed mRNA accumulation leads to protein synthesis perturbation and multisystem symptoms. Phenotype severity is correlated to expansion size and is most severe in the congenital form with hypotonia, respiratory failure, mental retardation and high mortality. Aims: To characterize the respiratory and neurobehavioural phenotypes of a mouse model of DM1 with large CTG expansion (>1500 repeats, DMSXL). Methods: Weight and temperature were recorded daily in wild-type, heterozygous and homozygous DMSXL pups from birth to postnatal day 30 (P30). Breathing variables and apnoea duration were measured using whole-body flow barometric plethysmography in air and in response to hypercapnia (8% CO₂) and hypoxia (10% O₂). Motor development was analysed using righting, cliff avoidance and negative geotaxis tests from P3 to P15 and gait quality assessment from P2 to P30. Results: Weight growth was significantly delayed in DMSXL mice, compared to WT mice. Morphological abnormalities were occasionally present. DMSXL showed significantly longer apnoea duration at P1 and P8. Otherwise breathing variables were normal. Righting and cliff avoidance reflexes were delayed; gait quality was significantly lower compared to controls. Conclusion: DMSXL mice display key features of DM1 and may serve as a model to analyse pathophysiological processes and test treatments.

Background: Hydrotherapy plays an important role in the rehabilitation of patients with spinal cord injury (SCI). In healthy subjects, immersion reduces pulmonary volumes. The effects of immersion on tetraplegic SCI subjects (a population with potential respiratory failure and increased abdominal compliance) are not as well known. Study aim: To observe the influence of two levels of immersion on the pulmonary function of tetraplegic SCI subjects, undergoing hydrotherapy as a part of their rehabilitation program. Methods: Ten adult spinal cord injury tetraplegic subjects (level of injury ranging from C4 to C7, ASIA A), at least three months post injury were included in a prospective open label study. Evaluation of pulmonary function was carried out in air, and in water in two levels of immersion (cervical and xyphoid). Lung volumes, forced ventilatory flows and static mouth pressures were measured. Respiratory comfort was evaluated. Results: Functional residual capacity increasingly and significantly decreased with immersion level, resulting from a fall of both residual volume and expiratory reserve volume while vital capacity remained stable. Maximal respiratory pressures remained stable regardless level of immersion while respiratory comfort tended to decrease with increasing depth of immersion. Conclusions: Lung volumes changes observed in SCI tetraplegic patients follow a similar pattern to that observed in healthy subjects. Water immersion level does not seem to be a limiting factor for the use of hydrotherapy in this population.