Contribution of Transcutaneous PCO2 in Obesity Hypoventilation Syndrome.

BACKGROUND: More and more patients have obesity-hypoventilation syndrome (OHS) because of the increasing prevalence of obesity. The accuracy of transcutaneous PCO2 (PtcCO2 ) has recently been validated. However, no study evaluated the interest of measuring systematically nocturnal PtcCO2 in the follow-up of patients with OHS and home mechanical ventilation to detect residual nocturnal hypoventilation. We aimed to evaluate the contribution of nocturnal PtcCO2 to assess nocturnal hypoventilation compared with current routine examinations, that is, daytime arterial blood gases and nocturnal pulse oximetry. METHODS: A prospective monocentric pilot study was conducted from August 2018 to November 2019. Patients with stable OHS and who were treated with home noninvasive ventilation for at least 6 months were eligible to participate. After oral consent, we performed both diurnal arterial blood gases and combined home oximetry and capnography. The primary end point was the presence of residual nocturnal hypoventilation, defined as PaCO2 > 45 mm Hg or bicarbonate ≥ 27 mmol/L, SpO2 < 90% for ≥ 10% of the night, or PtcCO2 > 49 mm Hg for ≥ 10% of the night. RESULTS: A total of 32 subjects were included. Twenty-nine subjects with nocturnal PtcCO2 were analyzed. Eighteen of the 29 subjects showed residual nocturnal hypoventilation. The association of diurnal arterial blood gases and nocturnal pulse oximetry revealed nocturnal hypoventilation in only 9 subjects. Among the 19 subjects with both normal blood gases and normal nocturnal pulse oximetry, 11 had nocturnal hypoventilation with transcutaneous capnography. Only one subject presented with hypoventilation symptoms (asthenia). CONCLUSIONS: The assessment of PtcCO2 in comparison with nocturnal pulse oximetry and arterial blood gases provides important information for the diagnosis of residual nocturnal hypoventilation in the subjects with OHS who were ventilated at home.

Evaluation of the Post-COVID-19 Functional Status (PCFS) Scale in a cohort of patients recovering from hypoxemic SARS-CoV-2 pneumonia.

INTRODUCTION: COVID-19 sequelae are numerous and multisystemic, and how to evaluate those symptomatic patients is a timely issue. Klok et al proposed the Post-COVID-19 Functional Status (PCFS) Scale as an easy tool to evaluate limitations related to persistent symptoms. Our aim was to analyse PCFS Scale ability to detect functional limitations and its correlation with quality of life in a cohort of patients, 2-9 months after hospitalisation for COVID-19 hypoxemic pneumonia. METHODS: PCFS Scale was evaluated in 121 patients together with quality of life and dyspnoea questionnaires, pulmonary function tests and CT scans. RESULTS: We observed a high correlation with multiple questionnaires (Short Form-36, Hospital Anxiety and Depression Scale, modified Medical Research Council, end Borg Six-Minute Walk Test), making the PCFS Scale a quick and global tool to evaluate functional limitations related to various persistent symptoms following COVID-19 pneumonia. DISCUSSION: The PCFS Scale seems to be a suitable instrument to screen for patients who will require careful follow-up after COVID-19 hypoxemic pneumonia even in the absence of pulmonary sequelae.

Contribution of Hypoxic Exercise Testing to Predict High-Altitude Pathology: A Systematic Review.

Altitude travelers are exposed to high-altitude pathologies, which can be potentially serious. Individual susceptibility varies widely and this makes it difficult to predict who will develop these complications. The assessment of physiological adaptations to exercise performed in hypoxia has been proposed to help predict altitude sickness. The purpose of this review is to evaluate the contribution of hypoxic exercise testing, achieved in normobaric conditions, in the prediction of severe high-altitude pathology. We performed a systematic review using the databases PubMed, Science Direct and Embase in October 2021 to collect studies reporting physiological adaptations under hypoxic exercise testing and its interest in predicting high-altitude pathology. Eight studies were eligible, concerning 3558 patients with a mean age of 46.9 years old, and a simulated mean altitude reaching of 5092 m. 597 patients presented an acute mountain sickness during their altitude travels. Three different protocols of hypoxic exercise testing were used. Acute mountain sickness was defined using Hackett's score or the Lake Louise score. Ventilatory and cardiac responses to hypoxia, desaturation in hypoxia, cerebral oxygenation, core temperature, variation in body mass index and some perceived sensations were the highlighted variables associated with acute mountain sickness. A decision algorithm based on hypoxic exercise tests was proposed by one team. Hypoxic exercise testing provides promising information to help predict altitude complications. Its interest should be confirmed by different teams.

Reference Values of Forced Vital Capacity and Expiratory Flow in High-Level Cyclists.

Several studies have demonstrated that spirometric theoretical values may not be applicable to the high-level sports population. No reference values exist for high-level professional cyclists. We aimed to establish predictive spirometric values by reference equations. One hundred and forty-five French Caucasian high-level professional cyclists, aged 18-38, performed basic anthropometric assessment and spirometry during the medical evaluation at the beginning of the sport season. Measured values were compared with theoretical values. Predictive equations were established from anthropometric parameters to explain variations of spirometric parameters. High-level cyclists had significantly higher spirometric values than the theoretical values established from a general population, except for forced expiratory volume in one second (FEV1), forced vital capacity (FVC) and forced expiratory flow (FEF) at 25% of FVC. Only FVC and FEV1 were well predicted from body height. The FVC variation of 43.5% is explained by body height and weight. The FEV1 variation of 25.8% is explained only by body height. High-level cycling is associated with important respiratory adaptations depending on the body height and the sport specificity: intensive and prolonged endurance training. These findings are interesting for clinical individual application to diagnose obstructive disease and test reversibility with bronchodilator drugs.

Effects of Altitude on Chronic Obstructive Pulmonary Disease Patients: Risks and Care.

Air travel and altitude stays have become increasingly frequent within the overall population but also in patients suffering from chronic obstructive pulmonary disease (COPD), which is the most common respiratory disease worldwide. While altitude is well tolerated by most individuals, COPD patients are exposed to some serious complications, that could be life-threatening. COPD patients present not only a respiratory illness but also frequent comorbidities. Beyond oxygen desaturation, it also affects respiratory mechanics, and those patients are at high risk to decompensate a cardiac condition, pulmonary hypertension, or a sleep disorder. Recently, there has been considerable progress in the management of this disease. Nocturnal oxygen therapy, inhaled medications, corticosteroids, inspiratory muscle training, and pulmonary rehabilitation are practical tools that must be developed in the comprehensive care of those patients so as to enable them to afford altitude stays.

Complex roles for reactive astrocytes in the triple transgenic mouse model of Alzheimer disease.

In Alzheimer disease (AD), astrocytes undergo complex changes and become reactive. The consequences of this reaction are still unclear. To evaluate the net impact of reactive astrocytes in AD, we developed viral vectors targeting astrocytes that either activate or inhibit the Janus kinase-signal transducer and activator of transcription 3 (JAK2-STAT3) pathway, a central cascade controlling astrocyte reaction. We aimed to evaluate whether reactive astrocytes contribute to tau as well as amyloid pathologies in the hippocampus of 3xTg-AD mice, an AD model that develops tau hyper-phosphorylation and amyloid deposition. JAK2-STAT3 pathway-mediated modulation of reactive astrocytes in 25% of the hippocampus of 3xTg-AD mice did not significantly influence tau phosphorylation or amyloid processing and deposition at early, advanced, and terminal disease stage. Interestingly, inhibition of the JAK2-STAT3 pathway in hippocampal astrocytes did not improve spatial memory in the Y maze but it did reduce anxiety in the elevated plus maze. Our unique approach to specifically manipulate reactive astrocytes in situ show they may impact behavioral outcomes without influencing tau or amyloid pathology.

Project paper for implementation of Malawi health institutions development project

A Howard University and Ministry of Health project proposal submissited to the United States Agency for International Development [USAID] for manpower development and training in the fields of MCH; PHC and child spacing