Historical cohort study examining comparative effectiveness of albuterol inhalers with and without integrated dose counter for patients with asthma or chronic obstructive pulmonary disease

This study was supported financially by an unrestricted grant from Teva Pharmaceuticals, Frazer, PA, USA. The authors thank Jenny Fanstone of Fanstone Medical Communications Ltd., UK, and Elizabeth V Hillyer for medical writing support, funded by Research in Real-Life. We acknowledge with gratitude Dr Ruchir Parikh for his review of and contributions to the manuscript.

Évaluation pharmacoéconomique d'un traitement préventif des infections respiratoires aiguës chez les patients atteints de maladie pulmonaire obstructive chronique

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Symptom burden and its relationship to functional performance in patients with chronic obstructive pulmonary disease

The aim of this study was to explore symptom burden and its relationship to functional performance in patients with COPD. A descriptive, cross-sectional, correlational survey design was used and a sample of 214 patients with COPD. The sample was recruited from patients attending one of the major teaching hospitals in Dublin. Symptom burden was measured using the Memorial Symptom Assessment Scale (MSAS), and the functional performance was measured using the Functional Performance Inventory-Short Form (FPISF). Findings revealed that participants experienced a median of 13 symptoms. The most burdensome symptoms were shortness of breath, lack of energy, difficulty sleeping, worrying, dry mouth, feeling nervous, feeling irritable, and feeling sad. Participants with very severe COPD had the greatest symptom burden, followed by those with severe COPD, moderate COPD, and mild COPD. Symptom burden was higher for the psychological symptoms compared to the physical symptoms. Participants with mild COPD had the highest functional performance, followed by those with moderate COPD, very severe COPD, and severe COPD. Twenty symptoms were negatively correlated with overall functional performance, indicating that high symptom burden for those symptoms was associated with low overall functional performance. Moderate, negative, statistically significant correlations were found between the total symptom burden and overall functional performance, physical symptom burden and overall functional performance and psychological symptom burden and overall functional performance. A negative linear relationship was found between total symptom burden and overall functional performance among all stages of COPD except the mild group. No relationship was found between total symptom burden and overall functional performance for the moderate group. Healthcare professionals need to broaden the clinical and research assessment of physical and psychological symptoms in COPD; alleviating the burden of these symptoms may promote improved functional performance.

Évaluation pharmacoéconomique d'un traitement préventif des infections respiratoires aiguës chez les patients atteints de maladie pulmonaire obstructive chronique

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

STRUCTURAL AND FUNCTIONAL CORRELATES OF EXERCISE VENTILATORY INEFFICIENCY IN CHRONIC OBSTRUCTIVE PULMONARY DISEASE PATIENTS WITH MILD-TO-MODERATE SPIROMETRIC ABNORMALITIES

Background: Individuals with chronic obstructive pulmonary disease (COPD) have higher than normal ventilatory equivalents for carbon dioxide (VE/VCO2) during exercise. There is growing evidence that emphysema on thoracic computed tomography (CT) scans is associated with poor exercise capacity in COPD patients with only mild-to-moderate airflow obstruction. We hypothesized that emphysema is an underlying cause of microvascular dysfunction and ventilatory inefficiency, which in turn contributes to reduced exercise capacity. We expected ventilatory inefficiency to be associated with a) the extent of emphysema; b) lower diffusing capacity for carbon monoxide; c) a reduced pulmonary blood flow response to exercise; and d) reduced exercise capacity. Methods: In a cross-sectional study, 19 subjects with mild-to-moderate COPD (mean ± SD FEV1= 82 ± 13% predicted, 12 GOLD grade 1) and 26 age-, sex-, and activity-matched controls underwent a ramp-incremental symptom-limited exercise test on a cycle ergometer. Ventilatory inefficiency was assessed by the minimum VE/VCO2 value (nadir). A subset of subjects also completed repeated constant work rate exercise bouts with non-invasive measurements of pulmonary blood flow. Emphysema was quantified as the percentage of attenuation areas below -950 Housefield Units on CT scans. An electronic scoresheet was used to keep track of emphysema sub-types. Results: COPD subjects typically had centrilobular emphysema (76.8 ± 10.1% of total emphysema) in the upper lobes (upper/lower lobe ratio= 0.82 ± 0.04). They had lower peak oxygen uptake (VO2), higher VE/VCO2 nadir and greater dyspnea scores than controls (p<0.05). Lower peak O2 and worse dyspnea were found in COPD subjects with VE/VCO2 nadirs ≥ 30. COPD subjects had blunted increases in pulmonary blood flow from rest to iso-VO2 exercise (p<0.05). Higher VE/VCO2 nadir in COPD subjects correlated with emphysema severity (r= 0.63), which in turn correlated with reduced lung diffusing capacity (r= -0.72) and blunted changes in pulmonary blood flow from rest to exercise (r= -0.69) (p<0.01). Conclusions: Ventilation “wasted” in emphysematous areas is associated with reduced exercise ventilatory efficiency in mild-to-moderate COPD. Exercise ventilatory inefficiency links structure (emphysema) and function (gas transfer) to a key clinical outcome (reduced exercise capacity) in COPD patients with modest spirometric abnormalities.

Shiftwork, sleep disturbance and the metabolic syndrome among female hospital workers

Background: Shiftwork is associated with increased sleep disturbance and cardiovascular and metabolic disease risk. This thesis will focus on shiftwork-related sleep disturbance and the potential mediating role of reduced sleep duration in the relationship between a current rotational shiftwork schedule and the metabolic syndrome among female hospital employees. Objectives: 1) To describe sleep patterns in relation to different shiftwork exposure metrics (current status, cumulative exposure, number of consecutive night shifts); 2) To assess the association between shiftwork metrics and sleep duration; 3) To determine whether sleep duration on work shifts mediates the relationship between a current rotational shiftwork pattern and the metabolic syndrome; and 4) To assess whether cumulative shiftwork exposure and the number of consecutive night shifts are associated with the metabolic syndrome. Methods: 294 female hospital employees (142 rotating shiftworkers, 152 dayworkers) participated in a cross-sectional study. Shiftwork parameters were determined through self-report. Sleep was measured for one week with the ActiGraph GT3X+, a tri-axial accelerometer. The metabolic syndrome was defined according to the Joint Interim Studies Consensus Statement. Sleep was described by shiftwork exposure parameters, and multivariable linear regression was used to determine associations between shiftwork variables and sleep duration. Regression path analysis was used to assess whether sleep duration was a mediator between a current shiftwork schedule and the metabolic syndrome, and the significance of the indirect (mediating) effect was tested with bootstrap confidence intervals. Logistic regression was used to determine associations between cumulative shiftwork exposure, number of consecutive night shifts, and the metabolic syndrome. Results: Current shiftworkers slept less on work shifts, more on free days, and were more likely to nap compared to dayworkers. Sleep duration on work shifts was a strong intermediate in the relationship between a current shiftwork pattern and the metabolic syndrome. Cumulative shiftwork exposure and the number of consecutive night shifts did not affect sleep or the metabolic syndrome. Conclusions: A current shiftwork pattern disrupts sleep, and reduced sleep duration is an important intermediate between shiftwork and the metabolic syndrome among female hospital employees.

Sleep Quality as a Mediator of the Relationship Between Attachment Anxiety and Health Outcomes During Romantic Conflict

Attachment anxiety, or a fear of abandonment by those close to you, is an important predictor of many individual and interpersonal outcomes. Individuals high in attachment anxiety are more likely to experience physical illness due to disrupted immune functioning and deregulated stress responses. I was interested in examining potential mechanisms accounting for why individuals high in attachment anxiety are more likely to become ill. One variable that has been demonstrated to mediate the relationship between stress and health is sleep quality. As attachment anxiety is characterized by the experience of stress and worry over abandonment by romantic partners, I predicted sleep quality would mediate the relationship between attachment anxiety and health. Further, I predicted attachment anxiety would interact with romantic threat, in that individuals high in attachment anxiety who perceive threat to their relationships would have poor sleep quality (compared with individuals low in attachment anxiety and individuals high in anxiety who do not perceive threat) which would mediate the most unhealthy outcomes. I tested these hypotheses using three online diary studies. In the first two studies, participants completed a seven-night diary describing their sleep quality, health, and interaction with their partner. In Study 3, I surveyed participants once a week for eight weeks to examine longer-term health outcomes. Sleep quality did indeed mediate the relationship between attachment anxiety and various health outcomes over one week (Study 2), and showed a trend towards mediating effects over two months (Study 3). Interestingly, however, attachment anxiety did not interact with perceived romantic threat to predict health in the mediation analyses. Implications for sleep as a mediating variable are discussed, as well as the lack of attachment anxiety by romantic threat interaction.

DESCRIBING SLEEP AND SEDATION PRACTICES IN THE ICU: A MULTINATIONAL SURVEY

Introduction Sleep disturbances are common in critically ill patients treated in the intensive care unit (ICU) with the potential for serious consequences and long-term effects on health outcomes and patient morbidity.
Objectives Our aim was to describe sleep management and sedation practices of adult ICUs in ten countries and to evaluate roles and responsibilities of the ICU staff in relation to key sleep and sedation decisions.
Methods A multicenter, self-administered survey sent to nurse managers of adult ICUs across 10 countries. The questionnaire comprised four domains: sleep characteristics of the critically ill; sleep and sedation practices; non-pharmacological and pharmacological interventions used to improve sleep; and the autonomy and influence of nurses on sleeping practices in the ICU.
Results Overall response rate was 66% (range 32% UK to 100% Cyprus), providing data from 522 ICUs. In all countries, the most frequent patient characteristic perceived to identify sleep was lying quietly with closed eyes (N=409, 78%) (range 92% Denmark to 36% Italy). The most commonly used sedation scale was the Richmond Agitation-Sedation Score (RASS) (N=220, 42%) (range 81% UK to 0% Denmark, Cyprus where most ICUs used the Ramsay score). In most ICUs, selection of sleep medication (N=265, 51%) and assessment of effect (N=309, 59%) was performed by physicians and nurses based on collaborative discussion. In a minority of ICUs (N=161, 31%), decisions and assessments were made by physicians alone. The most commonly used (in all countries) non-pharmacological intervention to promote sleep was reducing ICU staff noise (N=473, 91%) (range 100% Denmark, Norway to 78% Canada). Only 95 ICUs (18%) used earplugs on a frequent basis (range 0% Greece, Cyprus, Denmark to 57% Sweden). Propofol was the drug used most commonly for sedation (N=359, 69%) (range 96% Sweden to 29% Canada). Chloral hydrate was used by only 63 (12%) ICUs (range 0% Greece, Cyprus, Denmark, Italy to 56% Germany). Sedation scales were used on a routine basis by 77% of the 522 ICUs. Participants scored nursing autonomy for sleep and sedation management as moderate; median score of 5 (scale of 0 to 10), range 7 (Canada, Greece, Sweden) to 4 (Norway, Poland). Nursing influence on sleep and sedation decisions was perceived considerable; median score 8, range 9 (Denmark) to 5 (Poland).
Conclusions We found considerable across country variation in sleep promotion and sedation management practices though most have adopted a sedation scale as recommended in professional society guidelines. Most ICUs in all countries used a range of pharmacological and non-pharmacological interventions to promote sleep. Most units reported inter-professional decision-making with nurses perceived to have substantial influence on sleep/sedation decisions.

Non-contact Pressure-based Sleep/Wake Discrimination

Poor sleep is increasingly being recognised as an important prognostic parameter of health. For those with suspected sleep disorders, patients are referred to sleep clinics which guide treatment. However, sleep clinics are not always a viable option due to their high cost, a lack of experienced practitioners, lengthy waiting lists and an unrepresentative sleeping environment. A home-based non-contact sleep/wake monitoring system may be used as a guide for treatment potentially stratifying patients by clinical need or highlighting longitudinal changes in sleep and nocturnal patterns. This paper presents the evaluation of an under-mattress sleep monitoring system for non-contact sleep/wake discrimination. A large dataset of sensor data with concomitant sleep/wake state was collected from both younger and older adults participating in a circadian sleep study. A thorough training/testing/validation procedure was configured and optimised feature extraction and sleep/wake discrimination algorithms evaluated both within and across the two cohorts. An accuracy, sensitivity and specificity of 74.3%, 95.5%, and 53.2% is reported over all subjects using an external validation
dataset (71.9%, 87.9% and 56%, and 77.5%, 98% and 57% is reported for younger and older subjects respectively). These results compare favourably with similar research, however this system provides an ambient alternative suitable for long term continuous sleep monitoring, particularly amongst vulnerable populations.

Selective Coupling between Theta Phase and Neocortical Fast Gamma Oscillations during REM-Sleep in Mice

TORT, A. B. L. ; SCHEFFER-TEIXEIRA, R ; Souza, B.C. ; DRAGUHN, A. ; BRANKACK, J. . Theta-associated high-frequency oscillations (110-160 Hz) in the hippocampus and neocortex. Progress in Neurobiology , v. 100, p. 1-14, 2013.

Influence of frequent nightmares on REM sleep-dependent emotional memory processing

La littérature suggère que le sommeil paradoxal joue un rôle dans l'intégration associative de la mémoire émotionnelle. De plus, les rêves en sommeil paradoxal, en particulier leur nature bizarre et émotionnelle, semblent refléter cette fonction associative et émotionnelle du sommeil paradoxal. La conséquence des cauchemars fréquents sur ce processus est inconnue, bien que le réveil provoqué par un cauchemar semble interférer avec les fonctions du sommeil paradoxal. Le premier objectif de cette thèse était de reproduire conceptuellement des recherches antérieures démontrant que le sommeil paradoxal permet un accès hyper-associatif à la mémoire. L'utilisation d'une sieste diurne nous a permis d'évaluer les effets du sommeil paradoxal, comparativement au sommeil lent et à l’éveil, sur la performance des participants à une tâche sémantique mesurant « associational breadth » (AB). Les résultats ont montré que seuls les sujets réveillés en sommeil paradoxal ont répondu avec des associations atypiques, ce qui suggère que le sommeil paradoxal est spécifique dans sa capacité à intégrer les traces de la mémoire émotionnelle (article 1). En outre, les rapports de rêve en sommeil paradoxal étaient plus bizarres que ceux en sommeil lent, et plus intenses émotionnellement ; ces attributs semblent refléter la nature associative et émotionnelle du sommeil paradoxal (article 2). Le deuxième objectif de la thèse était de préciser si et comment le traitement de la mémoire émotionnelle en sommeil paradoxal est altéré dans le Trouble de cauchemars fréquents (NM). En utilisant le même protocole, nos résultats ont montré que les participants NM avaient des résultats plus élevés avant une sieste, ce qui correspond aux observations antérieures voulant que les personnes souffrant de cauchemars soient plus créatives. Après le sommeil paradoxal, les deux groupes, NM et CTL, ont montré des changements similaires dans leur accès associatif, avec des résultats AB-négatif plus bas et AB-positif plus grands. Une semaine plus tard, seul les participants NM a maintenu ce changement dans leur réseau sémantique (article 3). Ces résultats suggèrent qu’au fil du temps, les cauchemars peuvent interférer avec l'intégration de la mémoire émotionnelle pendant le sommeil paradoxal. En ce qui concerne l'imagerie, les participants NM avaient plus de bizarrerie et plus d’émotion positive, mais pas négative, dans leurs rêveries (article 4). Ces attributs intensifiés suggèrent à nouveau que les participants NM sont plus imaginatifs et créatifs à l’éveil. Dans l'ensemble, les résultats confirment le rôle du sommeil paradoxal dans l'intégration associative de la mémoire émotionnelle. Cependant, nos résultats concernant le Trouble de cauchemars ne sont pas entièrement en accord avec les théories suggérant que les cauchemars sont dysfonctionnels. Le groupe NM a montré plus d’associativité émotionnelle, de même que plus d'imagerie positive et bizarre à l’éveil. Nous proposons donc une nouvelle théorie de sensibilité environnementale associée au Trouble de cauchemar, suggérant qu'une sensibilité accrue à une gamme de contextes environnementaux sous-tendrait les symptômes uniques et la richesse imaginative observés chez les personnes souffrant de cauchemars fréquents. Bien que davantage de recherches doivent être faites, il est possible que ces personnes puissent bénéficier e milieux favorables, et qu’elles puissent avoir un avantage adaptatif à l'égard de l'expression créative, ce qui est particulièrement pertinent lorsque l'on considère leur pronostic et les différents types de traitements.

Sleep and school education

Sleep has emerged in the past decades as a key process for memory consolidation and restructuring. Given the universality of sleep across cultures, the need to reduce educational inequality, the low implementation cost of a sleep-based pedagogy, and its global scalability, it is surprising that the potential of improved sleep as a means of enhancing school education has remained largely unexploited. Students of various socio-economic status often suffer from sleep deficits. In principle, the optimization of sleep schedules both before and after classes should produce large positive benefits for learning. Here we review the biological and psychological phenomena underlying the cognitive role of sleep, present the few published studies on sleep and learning that have been performed in schools, and discuss potential applications of sleep to the school setting. Translational research on sleep and learning has never seemed more appropriate.

Mania Triggered by Sleep Loss: Implications for Postpartum Psychosis

Background and Aims To examine whether a history of mood episodes triggered by sleep loss is associated with (1) postpartum psychosis (PP) and (2) more broadly-defined postpartum mood episodes that included postnatal depression (PND), in women with bipolar disorder (BD). Methods Participants were 622 parous women with a diagnosis of bipolar-I disorder recruited in the UK to the Bipolar Disorder Research Network. Diagnosis and perinatal episodes were assessed via interview and case note data. Women were also asked during the interview whether episodes of mania and/or depression were triggered by sleep loss. We compared the rates of PP and PND within women who did and did not endorse sleep loss as a trigger of mood episodes. Results Women who reported that their episodes of mania were usually triggered by sleep loss were twice as likely to have experienced an episode of PP (OR = 2.00, 95% CI = 1.20–3.36) than women who did not report this. This effect remained significant when controlling for clinical and demographic factors. We found no significant associations between depression triggered by sleep loss and PP. Analyses in which we defined postpartum episodes at a broader level to include both PP and PND were not significant. Conclusions In pregnant women with BD, a history of mania following sleep loss could be a potential marker of vulnerability to severe postpartum episodes. Further study in prospective samples is required in order to confirm these findings, which may have important implications for understanding the aetiology of PP and of mood disorders more generally.