Sleep quality and architecture in COPD: the relationship with lung function abnormalities.

OBJECTIVE: Impaired respiratory mechanics and gas exchange may contribute to sleep disturbance in patients with COPD. We aimed to assess putative associations of different domains of lung function (airflow limitation, lung volumes, and gas exchange efficiency) with polysomnography (PSG)-derived parameters of sleep quality and architecture in COPD. METHODS: We retrospectively assessed data from COPD 181 patients ≥ 40 years of age who underwent spirometry, plethysmography, and overnight PSG. Univariate and multivariate linear regression models predicted sleep efficiency (total sleep time/total recording time) and other PSG-derived parameters that reflect sleep quality. RESULTS: The severity of COPD was widely distributed in the sample (post-bronchodilator FEV1 ranging from 25% to 128% of predicted): mild COPD (40.3%), moderate COPD (43.1%), and severe-very severe COPD (16.6%). PSG unveiled a high proportion of obstructive sleep apnea (64.1%) and significant nocturnal desaturation (mean pulse oximetry nadir = 82.2% ± 6.9%). After controlling for age, sex, BMI, apnea-hypopnea index, nocturnal desaturation, comorbidities, and psychotropic drug prescription, FEV1/FVC was associated with sleep efficiency (ß = 25.366; R2 = 14%; p < 0.001), whereas DLCO predicted sleep onset latency (ß = -0.314; R2 = 13%; p < 0.001) and rapid eye movement sleep time/total sleep time in % (ß = 0.085; R2 = 15%; p = 0.001). CONCLUSIONS: Pulmonary function variables reflecting severity of airflow and gas exchange impairment, adjusted for some potential confounders, were weakly related to PSG outcomes in COPD patients. The direct contribution of the pathophysiological hallmarks of COPD to objectively measured parameters of sleep quality seems to be less important than it was previously assumed.

Sleep quality and architecture in COPD: the relationship with lung function abnormalities / Qualidade e arquitetura do sono na DPOC: relação com anormalidades da função pulmonar

ABSTRACT Objective: Impaired respiratory mechanics and gas exchange may contribute to sleep disturbance in patients with COPD. We aimed to assess putative associations of different domains of lung function (airflow limitation, lung volumes, and gas exchange efficiency) with polysomnography (PSG)-derived parameters of sleep quality and architecture in COPD. Methods: We retrospectively assessed data from COPD 181 patients ≥ 40 years of age who underwent spirometry, plethysmography, and overnight PSG. Univariate and multivariate linear regression models predicted sleep efficiency (total sleep time/total recording time) and other PSG-derived parameters that reflect sleep quality. Results: The severity of COPD was widely distributed in the sample (post-bronchodilator FEV1 ranging from 25% to 128% of predicted): mild COPD (40.3%), moderate COPD (43.1%), and severe-very severe COPD (16.6%). PSG unveiled a high proportion of obstructive sleep apnea (64.1%) and significant nocturnal desaturation (mean pulse oximetry nadir = 82.2% ± 6.9%). After controlling for age, sex, BMI, apnea-hypopnea index, nocturnal desaturation, comorbidities, and psychotropic drug prescription, FEV1/FVC was associated with sleep efficiency (β = 25.366; R2 = 14%; p < 0.001), whereas DLCO predicted sleep onset latency (β = −0.314; R2 = 13%; p < 0.001) and rapid eye movement sleep time/total sleep time in % (β = 0.085; R2 = 15%; p = 0.001). Conclusions: Pulmonary function variables reflecting severity of airflow and gas exchange impairment, adjusted for some potential confounders, were weakly related to PSG outcomes in COPD patients. The direct contribution of the pathophysiological hallmarks of COPD to objectively measured parameters of sleep quality seems to be less important than it was previously assumed.

RESUMO Objetivo: O comprometimento da mecânica respiratória e das trocas gasosas pode contribuir para distúrbios do sono em pacientes com DPOC. Objetivamos avaliar associações putativas de diferentes domínios da função pulmonar (limitação do fluxo aéreo, volumes pulmonares e eficiência das trocas gasosas) com parâmetros da qualidade e arquitetura do sono na DPOC derivados da polissonografia (PSG). Métodos: Avaliamos retrospectivamente dados de 181 pacientes com DPOC e idade ≥ 40 anos que foram submetidos a espirometria, pletismografia e PSG de noite inteira. Modelos de regressão linear univariada e multivariada foram utilizados para avaliar a associação de variáveis de função pulmonar com a eficiência do sono (tempo total de sono/tempo total de registro) e outros parâmetros derivados da PSG que refletem a qualidade do sono. Resultados: A gravidade da DPOC foi bem distribuída na amostra (VEF1 pós-broncodilatador variando de 25% a 128% do previsto): DPOC leve (40,3%), DPOC moderada (43,1%) e DPOC grave-muito grave (16,6%). A PSG revelou uma alta frequência de apneia obstrutiva do sono (64,1%) e dessaturação noturna significativa (nadir médio da oximetria de pulso = 82,2% ± 6,9%). Após controle para idade, sexo, IMC, índice de apneia-hipopneia, dessaturação noturna, comorbidades e prescrição de psicotrópicos, a relação VEF1/CVF apresentou associação com a eficiência do sono (β = 25,366; R2 = 14%; p < 0,001), enquanto a DLCO previu a latência para o início do sono (β = −0,314; R2 = 13%; p < 0,001) e o tempo de sono rapid eye movement/tempo total de sono em % (β = 0,085; R2 = 15%; p = 0,001). Conclusões: As variáveis de função pulmonar que refletem a gravidade do comprometimento do fluxo aéreo e das trocas gasosas, ajustadas para alguns potenciais fatores de confusão, apresentaram fraca relação com os resultados da PSG nos pacientes com DPOC. A contribuição direta das características fisiopatológicas da DPOC para os parâmetros da qualidade do sono medidos objetivamente parece ser menos importante do que se supunha anteriormente.

Neurological complications associated with emerging viruses in Brazil.

OBJECTIVE: To test the hypotheses that emerging viruses are associated with neurological hospitalizations and that statistical models can be used to predict neurological sequelae from viral infections. METHODS: An ecological study was carried out to observe time trends in the number of hospitalizations with inflammatory polyneuropathy and Guillain-Barré syndrome (GBS) in the state of Rio de Janeiro from 1997 to 2017. Increases in GBS from month to month were assessed using a Farrington test. In addition, a cross-sectional study was conducted analyzing 50 adults hospitalized for inflammatory polyneuropathies from 2015 to 2017. The extent to which Zika virus symptoms explained GBS hospitalizations was evaluated using a calibration test. RESULTS: There were significant increases (Farrington test, P<0.001) in the incidence of GBS following the introduction of influenza A/H1N1 in 2009, dengue virus type 4 in 2013, and Zika virus in 2015. Of 50 patients hospitalized, 14 (28.0%) were diagnosed with arboviruses, 9 (18.0%) with other viruses, and the remainder with other causes of such neuropathies. Statistical models based on cases of emerging viruses accurately predicted neurological sequelae, such as GBS. CONCLUSION: The introduction of novel viruses increases the incidence of inflammatory neuropathies.

Effects of lung deflation induced by tiotropium/olodaterol on the cardiocirculatory responses to exertion in COPD.

BACKGROUND: Hyperinflation has been associated with negative cardiocirculatory consequences in patients with chronic obstructive pulmonary disease (COPD). These abnormalities are likely to worsen when the demands for O2 increase, e.g., under the stress of exercise. Thus, pharmacologically-induced lung deflation may improve cardiopulmonary interactions and exertional cardiac output leading to higher limb muscle blood flow and oxygenation in hyperinflated patients with COPD. METHODS: 20 patients (residual volume = 201.6 ±â€¯63.6% predicted) performed endurance cardiopulmonary exercise tests (75% peak) 1 h after placebo or tiotropium/olodaterol 5/5 µg via the Respimat® inhaler (Boehringer Ingelheim, Ingelheim am Rhein, Germany). Cardiac output was assessed by signal-morphology impedance cardiography. Near-infrared spectroscopy determined quadriceps blood flow (indocyanine green dye) and intra-muscular oxygenation. RESULTS: Tiotropium/olodaterol was associated with marked lung deflation (p < 0.01): residual volume decreased by at least 0.4 L in 14/20 patients (70%). The downward shift in the resting static lung volumes was associated with less exertional inspiratory constraints and dyspnoea thereby increasing exercise endurance by ~50%. Contrary to our premises, however, neither central and peripheral hemodynamics nor muscle oxygenation improved after active intervention compared to placebo. These results were consistent with those found in a subgroup of patients showing the largest decrements in residual volume (p < 0.05). CONCLUSIONS: The beneficial effects of tiotropium/olodaterol on resting and operating lung volumes are not translated into enhanced cardiocirculatory responses to exertion in hyperinflated patients with COPD. Improvement in exercise tolerance after dual bronchodilation is unlikely to be mechanistically linked to higher muscle blood flow and/or O2 delivery.

Characteristics associated with mortality in patients with chronic obstructive pulmonary disease (COPD)-heart failure coexistence.

AimTo investigate if cardiac/pulmonary functional tests and variables obtained from clinical practice (body mass index, dyspnea, functional class, clinical judgment of disability to perform an exercise test and previous hospitalization rate) are related to mortality in patients with overlap chronic obstructive pulmonary disease (COPD) and chronic heart failure (CHF). BACKGROUND: Although the coexistence of COPD and CHF has been growingly reported, description of survival predictors considering the presence of both conditions is still scarce. METHODS: Using a cohort design, outpatients with the previous diagnosis of COPD and/or CHF that performed both spirometry and echocardiography in the same year were followed-up during a mean of 20.9±8.5 months.FindingsOf the 550 patients initially evaluated, 301 had both spirometry and echocardiography: 160 (53%) with COPD on isolation; 100 (33%) with CHF on isolation; and 41 (14%) with overlap. All groups presented similar mortality: COPD 17/160 (11%); CHF 12/100 (12%); and overlap 7/41 (17%) (P=0.73). In the overlap group (n=41), inability to exercise and hospitalization rate were the unique parameters associated with higher mortality (seven events) in univariate analyses. In conclusion, inability to exercise and hospitalization rate emerged as the unique parameters associated with mortality in our sample.

The relationship between fat-free mass index and pulmonary hyperinflation in COPD patients.

BACKGROUND AND OBJECTIVE: Reduced fat-free mass (FFM), a common finding in chronic obstructive pulmonary disease (COPD), may indirectly impact peak exercise capacity through a greater level of pulmonary hyperinflation. We aimed to investigate if FFM index (FFM/squared height) impacts exercise induced dynamic hyperinflation in COPD patients. METHODS: Fifty-four patients with moderate-to-very severe COPD performed a symptom limited incremental cardiopulmonary exercise tests with serial measurements of inspiratory capacity (IC). FFM was measured by whole-body bioelectrical impedance. RESULTS: Patients were 66.7 ± 7.7 years old with mean forced expiratory volume in 1 s (FEV1) of 1.08 ± 0.41 L (42 ± 15% of predicted). Peak exercise IC was significantly (P < 0.05) correlated with IC at rest (r = 0.78), FEV1(r = 0.66), FVC (r = 0.59), FFM (r = 0.38) and FFM index (r = 0.29). However, only FEV1 and rest IC predict peak IC (r = 0.86; P < 0.01) in a multivariate linear regression analysis. CONCLUSIONS: FFM index was weakly associated with peak exercise IC in COPD patients. However, it ceased to be an independent predictor when corrected for expiratory airflow limitation (FEV1) and lung hyperinflation at rest (rest IC).