Effects of lung volume reduction surgery on sleep quality and nocturnal gas exchange in patients with severe emphysema

Sleep features in Lymphangioleiomyomatosis and their relationship with disease severity: a pilot study

Lymphangioleiomyomatosis (LAM) is a rare pulmonary disease characterized by progressive airflow limitation. We conducted a pilot trial to investigate the incidence of sleep disorders, sleep quality and their relationship with disease severity. We performed pulmonary function tests, blood gas analysis, overnight 12-channels polysomnography and clinical assessments in 15 consecutive LAM patients. For statistics, p values < 0.05 were considered significant. Sleep efficiency (SE) was inversely correlated with RV/TLC (p = 0.035) and positively with daytime SpO2 (p = 0.010) and PaO2 (p = 0.011). Three cases had obstructive sleep apnea (OSA); seven patients (46.7%) showed a REMOSA. AHI_REM was correlated with FEV1% (r = 0.75, p = 0.003), TLC% (r = 0.57, p = 0.026), RV% (r = 0.8, p=<0.0001) and RV/TLC (r = 0.77, p = 0.001). No correlations were observed between anxiety/depression and SE, CAP rate, pulmonary function test variables and AHI_REM (p > 0.05). four subjects had nocturnal hypoxia (T90 ≥ 1% of TST) showing lower values of DLCO%, daytime SpO2%, PaO2, FEV1% and a higher value of VR/TLC comparing with the subgroup with normal T90 (p < 0.05). This pilot study shows that sleep alterations could be frequent in LAM and associated to disease severity. Nocturnal hypoxemia and SE were related to lung function impairment. A dysregulation of sleep seems to involve exclusively REM phase, while NREM appears to be preserved. This phenomenon might be linked to the pathophysiology of disease: our study, even with the limits of the small sample size, showed that the presence of REMOSA is related to the disease severity, in particular to the degree of airflow limitation and hyperinflation. More studies are needed to assess this topic.

Effect of Triple Therapy with Budesonide-Formoterol-Tiotropium Versus Placebo-Tiotropium on Sleep Quality in Patients with Chronic Obstructive Pulmonary Disease

Background

Factors responsible for poor sleep quality in patients with chronic obstructive pulmonary disease (COPD) includes the effects of medications. This study evaluates the effect of the inhaled triple therapy of budesonide-formoterol-tiotropium versus placebo-tiotropium on sleep quality in COPD patients.

Methods

Twenty-three patients (11 [48%] males; age 55 [51-60, 48--5] years; body mass index [BMI] 25 [22-30, 18-40] kg/m²; forced expiratory volume in 1 second [FEV₁]1.10 [0.80 -1.90, 0.60-2.80] L, 42 [31-62, 24-75] % predicted) were studied. Ten patients were randomized to budesonide-formoterol-tiotropium and 13 patients to placebo-tiotropium. At baseline and after 28 days, patients completed spirometry, polysomnography, an Epworth Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI), COPD-specific St George's Respiratory Questionnaire (SGRQ-C) and short form 36 (SF 36).

Results

After 28 days, there was a significant 29% increase in the bedtime FEV₁ in the budesonide-formoterol-tiotropium group (from 0.75 [0.55-1.30, 0.50-2.40] L to 1.00 [0.75-1.55, 0.50-3.00] L, p=0.031), with no change in the placebo-tiotropium group (from 1.20 [0.80-1.50, 0.60-1.90] L to 1.15 [0.75-1.55, 0.50-1.80] L, p=0.91). No significant change was found post treatment in sleep efficiency or total sleep time in both the budesonide-formoterol-tiotropium group (from 78 [72-92, 62-98]% to 88 [77-92, 40-98]%, p=0.70 and 290 [268-358, 252-382] min to 342 [303-358, 157-372] min, p=0.77, respectively) and the placebo-tiotropium group (from 82 [75-88, 46-93]% to 84 [77-87, 62-94]%, p=0.96 and 320 [292-350, 180-378] min to 339 [303-349, 241-366] min, p=0.79, respectively). While there was no significant change in the arousal index in the budesonide-formoterol-tiotropium group (9 [5-16, 0-48] arousals/hour to 14 [9-17, 2-36] arousals/hour, p=0.43), a significant increase was seen in the placebo-tiotropium group (11 [4-13, 3--2] arousals/hour to 17 [11-21, 2-33] arousals/hour, p=0.027). Similarly, there was no change in the ESS in the budesonide-formoterol-tiotropium group (6 [3-8, 0-11] to 6 [5-8, 0-1]), p=0.44), but a marginally significant increase in the placebo-tiotropium group (8 [5-12, 2-18] to 10 [7-13, 5-18], p=0.07), with a significant difference in the ESS 28 days post treatment between the 2 groups (6 [5-8, 0-11] versus 10 [7-13, 5-18], p=0.043). There was no significant change in nocturnal oxygenation, sleep architecture, PSQI, SGRQ-C, or SF 36 in both groups.

Conclusion

In patients with COPD, inhaled triple therapy with budesonide-formoterol-tiotropium as compared to placebo-tiotropium improves pulmonary function while preserving sleep quality and architecture.

Effects of endobronchial coils for endoscopic lung volume reduction on sleep in COPD patients with advanced pulmonary emphysema

PURPOSE

Treatment of advanced pulmonary emphysema with endobronchial coils can improve clinical outcomes like quality of life (QOL). Yet, patients with chronic obstructive pulmonary disease (COPD) are also known to suffer from reduced sleep quality. The effect of coil therapy on sleep has not yet been investigated. The primary aim of this study was to investigate sleep efficiency before and after coil treatment. Secondly, we investigated the effects on nocturnal breathing pattern, QOL, and physical activity.

METHODS

Polysomnography (PSG) testing was performed before (T0), 6 month after (T3), and 12 months after (T4) treatment with endobronchial coils. Further examinations included QOL by St George's Respiratory Questionnaire (SGRQ) and COPD assessment test (CAT), and physical activity using an accelerometer for 1 week after each visit.

RESULTS

Of 21 patients, 14 completed the study: 6 women; mean age 58.0 ± 4.9 years; BMI 22.6 ± 4.6 kg/m²; FEV₁ 28.6 ± 7.1% predicted; residual volume (RV) 278.2 ± 49.4% predicted. Sleep efficiency did not vary between baseline and follow-up examinations (T0 69.0 ± 15.8%; T3 70.9 ± 16.0%; T4 66.8 ± 18.9%). Non-REM respiratory rate decreased compared to baseline (T0 19.4 ± 3.9/min; T3 17.8 ± 3.5/min; T4 17.1 ± 3.1/min (p = 0.041; p = 0.030) and QOL improved meeting the minimal clinically important difference (MCID) (SGRQ, T3 -12.8 units; T4 -7.1 units; CAT: T3 -5.6 units; T4 -3.4 units). No increase in physical activity was recorded (light activity T0 31.9 ± 9.9; T3 30.8 ± 16.9; T4 26.3 ± 10.6 h/week).

CONCLUSIONS

Treatment with endobronchial coils did not influence objectively measured sleep quality or physical activity, but reduced nocturnal breathing frequency and improved QOL in severe emphysema patients.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02399514, First Posted: March 26, 2015.

Evaluation of the Vibe Actigraph in Patients With Chronic Obstructive Pulmonary Disease: A Pilot Study

STUDY OBJECTIVE

To validate the Vibe actigraph in assessing sleep-wake patterns compared to polysomnography (PSG) in patients with COPD.

METHODS

Nine stable COPD patients wore actigraphs while undergoing PSG. The correlation between total sleep time (TST), total sleep period (TSP), sleep onset latency (SOL), wake after sleep onset (WASO), and sleep efficiency was determined for corresponding measurements from the actigraph and PSG. Sensitivity, specificity, and positive and negative predictive values were calculated for the actigraph, considering PSG the gold standard. Levels of agreement between the variables of PSG and the actigraph were estimated using Bland-Altman plots.

RESULTS

A strong and statistically significant correlation was noted between PSG and the actigraph in detecting movement during sleep [mean activity score (counts)], TST and TSP (all r_s = 0.83; p = 0.005). The median agreement of sleep and wake counts between PSG and the actigraph was 73% and the Cohen's Kappa value was 0.66. The medians of sensitivity and specificity of the actigraph for detecting sleep versus PSG were 84 and 66%, respectively. The median positive and negative predictive values of the actigraph were 74 and 72%, respectively.

CONCLUSIONS

This study demonstrated that, under controlled laboratory conditions, the Vibe actigraph in its default settings is a promising tool for the detection of sleep-wake parameters in a small number of ambulatory patients with COPD. Clinical Impact: The actigraph used in this pilot study suggests that these devices could provide clinically relevant information in COPD to better understand the relationship between sleep and health in this population.

Metabolic syndrome prevalence in patients with obstructive sleep apnea syndrome and chronic obstructive pulmonary disease: Relationship with systemic inflammation

Objectives

Metabolic syndrome (MetS) is frequent in both chronic obstructive pulmonary disease (COPD) and Obstructive sleep apnea (OSA). The aim of this study was to assess the frequency of MetS and the status of systemic inflammation in overlap syndrome.

Methods

A total of 151 consecutive COPD patients were recruited in this cross‐sectional study. Spirometry and polysomnography were done in all patients. The MetS was defined according to the criteria of the International Diabetes Federation. Anthropometry, metabolic parameters and inflammatory biomarkers: IL‐6, TNF‐α, leptin, resistin and adiponectin were recorded.

Results

OSA was present in 19.2% COPD patients. Subjects with overlap syndrome had higher neck and waist circumference compared to those with COPD alone. Significant differences in levels of blood pressure, lipid metabolic and glucose metabolic were found between two groups with overlap and COPD, as well as inflammatory biomarkers. Prevalence of MetS was increased in overlap group. Multivariate logistic regression showed that BMI, systolic BP when fall asleep and recumbent angiotens levels as significant independent predictors of the presence of Mets in overlap syndrome.

Conclusion

This study shows that MetS is frequent in patients with overlap. Overlap syndrome indicates a higher cardiometabolic risk and higher levels of systemic inflammatory.

Pathogenesis of obstructive sleep apnea in individuals with the COPD + OSA Overlap syndrome versus OSA alone

Overlap syndrome (OVS) is the concurrence of chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA), and is associated with poor outcomes. We hypothesized that physiological changes in COPD may affect the pathogenesis of OSA in important ways. We therefore sought to measure the anatomical and nonanatomical OSA traits in individuals with OVS and compare to those with OSA alone. Patients with established OVS were recruited, along with age, gender, and BMI matched OSA only controls. Smoking and relevant comorbidities or medications were excluded. Subjects underwent baseline polysomnography followed by an overnight physiological research study to measure the OSA traits (Veupnea , Varousal , Vpassive , Vactive , and loop gain). Fifteen subjects with OVS and 15 matched controls with OSA alone were studied (overall 66 ± 8 years, 20% women, BMI 31 ± 4 kg/m2 , apnea-hypopnea index 49 ± 36/hr). Mixed-modeling was used to incorporate each measurement (range 52-270 measures/trait), and account for age, gender, and BMI. There were no significant differences in the traits between OVS and OSA subjects, although OVS subjects potentially tolerated a lower ventilation before arousal (i.e., harder to wake; p = .06). Worsened lung function was significantly associated with worsened upper airway response and more unstable breathing (p < .05 for all). Consistent differences in key OSA traits were not observed between OVS and OSA alone. However, worse lung function does appear to exert an influence on several OSA traits. These findings indicate that a diagnosis of OVS should not generally influence the approach to OSA, but that lung function might be considered if utilizing OSA trait-specific treatment.

Sleep disruption as a predictor of quality of life among patients in the subpopulations and intermediate outcome measures in COPD study (SPIROMICS)

Study Objectives

Sleep quality is poor among patients with chronic obstructive pulmonary disease (COPD), and studies show that sleep disturbance is associated with low overall quality of life in this population. We evaluated the impact of patient-reported sleep quality and sleep apnea risk on disease-specific and overall quality of life within patients with COPD enrolled in the SPIROMICS study, after accounting for demographics and COPD disease severity.

Methods

Baseline data from 1341 participants [892 mild/moderate COPD (FEV1 ≥ 50% predicted); 449 severe COPD (FEV1 < 50%)] were used to perform three nested (blocks) regression models to predict quality of life (Short Form-12 mental and physical components and St. George's Respiratory Questionnaire). Dependent measures used for the nested regressions included the following: Block1: demographics and smoking history; Block 2: disease severity (forced expiratory volume 1 s; 6 min walk test); Block 3: risk for obstructive sleep apnea (OSA; Berlin questionnaire); and Block 4: sleep quality (Pittsburgh Sleep Quality Index [PSQI]).

Results

Over half of participants with COPD reported poor sleep quality (Mean PSQI 6.4 ± 3.9; 50% with high risk score on the Berlin questionnaire). In all three nested regression models, sleep quality (Block 4) was a significant predictor of poor quality of life, over and above variables included in blocks 1-3.

Conclusions

Poor sleep quality represents a potentially modifiable risk factor for poor quality of life in patients with COPD, over and above demographics and smoking history, disease severity, and risk for OSA. Improving sleep quality may be an important target for clinical interventions.

Clinical Trial

SPIROMICS.

Clinical Trial URL

http://www2.cscc.unc.edu/spiromics/.

Clinical Trial Registration

ClinicalTrials.gov NCT01969344.

Circadian rest-activity rhythm in chronic obstructive pulmonary disease

To characterize circadian rest-activity rhythm in COPD, 26 cases (66.9 ± 8.5y) and 15 controls (63.0 ± 10.7y) were assessed by actimetry. Rhythm fragmentation was measured by intradaily variability (IV), while synchronization to the 24-h light-dark cycle was measured by interdaily stability (IS). The average activity during the least active 5-h period (L5) and the average activity during the most active 10-h period (M10) were used to calculate the relative amplitude mean [RAm = (M10-L5)/(M10+L5)]. COPD patients presented higher IVm (0.242 ± 0.097 vs 0.182 ± 0.063) and L5 (36.849 ± 18.239 vs 19.888 ± 12.268) and lower RAm (0.696 ± 0.134 vs 0.833 ± 0.093) than controls. Future studies on the effects of chronotherapy measures in COPD are warranted.

Fatigue and sleepiness determine respiratory quality of life among veterans evaluated for sleep apnea

Background

In those with symptoms indicative of obstructive sleep apnea (OSA), respiratory-specific health-related quality of life (HRQL) may be an important patient-centered outcome. The aim of this study was to assess the associations between sleepiness, fatigue, and impaired general and respiratory-specific HRQL among persons with suspected OSA.

Methods

We evaluated military veterans consecutively referred for suspected OSA with sleep studies yielding apnea-hypopnea index (AHI) values. They also completed the sleepiness (Epworth Sleepiness Scale [ESS]), and fatigue (Fatigue Severity Scale [FSS]) questionnaires, as well as two HRQL instruments (the generic Short-Form SF-12v2 yielding the Physical Component Scale [PCS] and the respiratory-specific Airways Questionnaire [AQ]-20R). Multiple linear regression tested the associations between ESS and FSS (standardized as Z scores for scaling comparability) with AQ-20R, accounting for AHI, SF-12v2-PCS and comorbid respiratory conditions other than OSA.

Results

We studied 1578 veterans (median age 61.1 [IQR 16.8] years; 93.9% males). Of these, 823 (52%) met AHI criteria for moderate to severe OSA (AHI ≥15/h). The majority reported excessive daytime sleepiness (53%; median ESS 11 [IQR 9]) or fatigue (61%; median FSS 42 [IQR 23]). The median AQ-20R was 4 [IQR 1–8]. Controlling for AHI, SF-12v2-PCS, respiratory co-morbid conditions, body mass index, and demographics, both ESS and FSS were significantly associated with poorer AQ-20R: for each; ESS, 1.6 points (95% CI 1.4–1.9), and for FSS, 2.5 points (95% CI, 2.3–2.7).

Conclusions

Greater daytime sleepiness and fatigue are associated with poorer respiratory-specific HRQL, over and above the effects of OSA, respiratory comorbidity, and generic physical HRQL.

Lung volume reduction surgery for diffuse emphysema

BACKGROUND

Lung volume reduction surgery (LVRS) performed to treat patients with severe diffuse emphysema was reintroduced in the nineties. Lung volume reduction surgery aims to resect damaged emphysematous lung tissue, thereby increasing elastic properties of the lung. This treatment is hypothesised to improve long-term daily functioning and quality of life, although it may be costly and may be associated with risks of morbidity and mortality. Ten years have passed since the last version of this review was prepared, prompting us to perform an update.

OBJECTIVES

The objective of this review was to gather all available evidence from randomised controlled trials comparing the effectiveness of lung volume reduction surgery (LVRS) versus non-surgical standard therapy in improving health outcomes for patients with severe diffuse emphysema. Secondary objectives included determining which subgroup of patients benefit from LVRS and for which patients LVRS is contraindicated, to establish the postoperative complications of LVRS and its morbidity and mortality, to determine which surgical approaches for LVRS are most effective and to calculate the cost-effectiveness of LVRS.

SEARCH METHODS

We identified RCTs by using the Cochrane Airways Group Chronic Obstructive Pulmonary Disease (COPD) register, in addition to the online clinical trials registers. Searches are current to April 2016.

SELECTION CRITERIA

We included RCTs that studied the safety and efficacy of LVRS in participants with diffuse emphysema. We excluded studies that investigated giant or bullous emphysema.

DATA COLLECTION AND ANALYSIS

Two independent review authors assessed trials for inclusion and extracted data. When possible, we combined data from more than one study in a meta-analysis using RevMan 5 software.

MAIN RESULTS

We identified two new studies (89 participants) in this updated review. A total of 11 studies (1760 participants) met the entry criteria of the review, one of which accounted for 68% of recruited participants. The quality of evidence ranged from low to moderate owing to an unclear risk of bias across many studies, lack of blinding and low participant numbers for some outcomes. Eight of the studies compared LVRS versus standard medical care, one compared two closure techniques (stapling vs laser ablation), one looked at the effect of buttressing the staple line on the effectiveness of LVRS and one compared traditional 'resectional' LVRS with a non-resectional surgical approach. Participants completed a mandatory course of pulmonary rehabilitation/physical training before the procedure commenced. Short-term mortality was higher for LVRS (odds ratio (OR) 6.16, 95% confidence interval (CI) 3.22 to 11.79; 1489 participants; five studies; moderate-quality evidence) than for control, but long-term mortality favoured LVRS (OR 0.76, 95% CI 0.61 to 0.95; 1280 participants; two studies; moderate-quality evidence). Participants identified post hoc as being at high risk of death from surgery were those with particularly impaired lung function, poor diffusing capacity and/or homogenous emphysema. Participants with upper lobe-predominant emphysema and low baseline exercise capacity showed the most favourable outcomes related to mortality, as investigators reported no significant differences in early mortality between participants treated with LVRS and those in the control group (OR 0.87, 95% CI 0.23 to 3.29; 290 participants; one study), as well as significantly lower mortality at the end of follow-up for LVRS compared with control (OR 0.45, 95% CI 0.26 to 0.78; 290 participants; one study). Trials in this review furthermore provided evidence of low to moderate quality showing that improvements in lung function parameters other than forced expiratory volume in one second (FEV1), quality of life and exercise capacity were more likely with LVRS than with usual follow-up. Adverse events were more common with LVRS than with control, specifically the occurrence of (persistent) air leaks, pulmonary morbidity (e.g. pneumonia) and cardiovascular morbidity. Although LVRS leads to an increase in quality-adjusted life-years (QALYs), the procedure is relatively costly overall.

AUTHORS' CONCLUSIONS

Lung volume reduction surgery, an effective treatment for selected patients with severe emphysema, may lead to better health status and lung function outcomes, specifically for patients who have upper lobe-predominant emphysema with low exercise capacity, but the procedure is associated with risks of early mortality and adverse events.

Intermittent hypoxia initiated plasticity in humans: A multipronged therapeutic approach to treat sleep apnea and overlapping co-morbidities

Over the past three decades exposure to intermittent hypoxia (IH) has generally been considered a stimulus associated with a number of detrimental outcomes. However, there is sufficient evidence to link IH to many beneficial outcomes but they have largely been ignored, particularly in the field of sleep medicine in the United States. Recent reviews have postulated that this apparent contradiction is related to the severity and duration of exposure to IH; mild forms of IH initiate beneficial outcomes while severe forms of IH are coupled to detrimental consequences. In the present review we explore the role that IH has in initiating respiratory plasticity and the potential this form of plasticity has to mitigate obstructive sleep apnea (OSA) in humans. In taking this approach, we address the possibility that IH could serve as an adjunct therapy coupled with continuous positive airway pressure (CPAP) to treat OSA. Our working hypothesis is that exposure to mild IH leads to respiratory plasticity that manifests in increased stability of the upper airway, which could ultimately reduce the CPAP required to treat OSA. In turn, this reduction could increase CPAP compliance and extend the length of treatment each night, which might improve the magnitude of outcome measures. Improved treatment compliance coupled with the direct effect that IH has on numerous overlapping conditions (i.e. asthma, chronic obstructive pulmonary disease, spinal cord injury) may well lead to substantial improvements that exceed outcomes following treatment with CPAP alone. Overall, this review will consider evidence from the published literature which suggests that IH could serve as an effective multipronged therapeutic approach to treat sleep apnea and its overlapping co-morbidities.

The effect of increased lung volume in chronic obstructive pulmonary disease on upper airway obstruction during sleep

Patients with chronic obstructive pulmonary disease (COPD) exhibit increases in lung volume due to expiratory airflow limitation. Increases in lung volumes may affect upper airway patency and compensatory responses to inspiratory flow limitation (IFL) during sleep. We hypothesized that COPD patients have less collapsible airways inversely proportional to their lung volumes, and that the presence of expiratory airflow limitation limits duty cycle responses to defend ventilation in the presence of IFL. We enrolled 18 COPD patients and 18 controls, matched by age, body mass index, sex, and obstructive sleep apnea disease severity. Sleep studies, including quantitative assessment of airflow at various nasal pressure levels, were conducted to determine upper airway mechanical properties [passive critical closing pressure (Pcrit)] and for quantifying respiratory timing responses to experimentally induced IFL. COPD patients had lower passive Pcrit than their matched controls (COPD: -2.8 ± 0.9 cmH2O; controls: -0.5 ± 0.5 cmH2O, P = 0.03), and there was an inverse relationship of subject's functional residual capacity and passive Pcrit (-1.7 cmH2O/l increase in functional residual capacity, r(2) = 0.27, P = 0.002). In response to IFL, inspiratory duty cycle increased more (P = 0.03) in COPD patients (0.40 to 0.54) than in controls (0.41 to 0.51) and led to a marked reduction in expiratory time from 2.5 to 1.5 s (P < 0.01). COPD patients have a less collapsible airway and a greater, not reduced, compensatory timing response during upper airway obstruction. While these timing responses may reduce hypoventilation, it may also increase the risk for developing dynamic hyperinflation due to a marked reduction in expiratory time.

Sleep disorders in chronic obstructive pulmonary disease: etiology, impact, and management

ABSTRACT

Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality and may frequently be complicated by sleep disorders. Insomnia and obstructive sleep apnea are commonly encountered in patients with COPD. Nocturnal hypoxemia is also prevalent in COPD may occur despite adequate awake oxygenation and can be especially severe in rapid eye movement sleep. Additionally, several factors--some of them unique to COPD--can contribute to sleep-related hypoventilation. Recognition of hypoventilation can be vital as supplemental oxygen therapy itself can acutely worsen hypoventilation and lead to disastrous consequences. Finally, accruing data establish an association between restless leg syndrome and COPD--an association that may be driven by hypoxemia and/or hypercapnia. Comorbid sleep disorders portend worse sleep quality, diminished quality of life, and multifarious other adverse consequences. The awareness and knowledge regarding sleep comorbidities in COPD has continued to evolve over past many years. There are still several lacunae, however, in our understanding of the etiologies, impact, and therapies of sleep disorders, specifically in patients with COPD. This review summarizes the latest concepts in prevalence, pathogenesis, diagnosis, and management of diverse sleep disorders in COPD.

Update on obstructive sleep apnea and its relation to COPD

Chronic obstructive pulmonary disease (COPD) is a common and preventable lung disease that affects millions of people in the United States. Sleep disorders including obstructive sleep apnea (OSA) are also common. It is not surprising that many people with COPD also suffer from OSA. This relationship, however, puts people at risk for more nocturnal desaturations and potential complications related to this, including pulmonary hypertension and heart rhythm disturbances. This update focuses on the physiology of sleep disturbances in COPD as well as the clinical implications of OSA in COPD.

Sleep-induced hypoxaemia in patients with chronic obstructive pulmonary disease

Patients with moderate or severe chronic obstructive pulmonary disease run a high risk of developing sleep-induced hypoxaemia, because of alveolar hypoventilation and ventilation-perfusion mismatch. This article looks at the prevalence, significance and treatment of sleep-induced hypoxaemia in chronic obstructive pulmonary disease.

Long-term oxygen therapy

Long-term oxygen therapy (LTOT) has been shown to reduce pulmonary hypertension and improve survival in patients with chronic obstructive pulmonary disease and resting hypoxemia (reduced arterial partial pressure of oxygen ≤55 mmHg). However, the benefit of its use for chronic pulmonary diseases other than chronic obstructive pulmonary disease as well as for nonpulmonary conditions is debatable. Its role in patients with mild hypoxemia (reduced arterial partial pressure of oxygen >55 mmHg at rest) is presently being investigated in the LOTT. A meta-analysis of four controlled trials reporting the role of LTOT in patients with either nocturnal desaturation or daytime moderate hypoxemia found no difference in survival between patients on LTOT than those without. Advances in oxygen delivery and conservation devices have made domiciliary oxygen therapy more practical and popular for patients. There still remain concerns with the actual compliance of therapy among the needy patients.

Pulmonary rehabilitation improves sleep quality in chronic lung disease

Sleep-related disorders are common in patients with chronic obstructive pulmonary disease (COPD) and, possibily, other lung disorders. Exercise has been shown to improve sleep disturbances. In patients with COPD, pulmonary rehabilitation (PR) produces important health benefits with improvement in symptoms, exercise tolerance, and quality of life. However, the effect of PR on sleep quality remains unknown. The aim of this observational study was to evaluate sleep quality in patients with chronic lung disease and the role of PR as a non-pharmacologic treatment to improve sleep. Sixty-four patients with chronic lung disease enrolled in an 8-week comprehensive PR program, and completed the study (48% male; obstructive [72%], restrictive [20%], mixed [8%]; 44% on supplemental oxygen). Baseline spirometry [mean (SD)]: FEV1% pred = 48.9 (17.4), FVC% pred = 72.5 (18.1), and FEV1/FVC% = 53.1 (18.9). Exercise tolerance and questionnaires related to symptoms, health-related quality of life (HRQL), and sleep quality using the Pittsburgh Sleep Quality Index (PSQI) were obtained before and after PR. 58% reported poor sleep quality (PSQI > 5) at baseline. Sleep quality improved by 19% (p = 0.017) after PR, along with significant improvements in dyspnea, exercise tolerance, self-efficacy, and HRQL. Sleep quality in patients with chronic lung disease was poor. In addition to expected improvements in symptoms, exercise tolerance, and HRQL after PR, the subgroup of patients with COPD had a significant improvement in sleep quality. These findings suggest that PR may be an effective, non-pharmacologic treatment option for sleep problems in patients with COPD.

[Lung volume reduction surgery for emphysema and bullous pulmonary emphysema]

The improvement of respiratory symptoms for emphysematous patients by surgery is a concept that has evolved over time. Initially used for giant bullae, this surgery was then applied to patients with diffuse microbullous emphysema. The physiological and pathological concepts underlying these surgical procedures are the same in both cases: improve respiratory performance by reducing the high intrapleural pressure. The functional benefit of lung volume reduction surgery (LVRS) in the severe diffuse emphysema has been validated by the National Emphysema Treatment Trial (NETT) and the later studies which allowed to identify prognostic factors. The quality of the clinical, morphological and functional data made it possible to develop recommendations now widely used in current practice. Surgery for giant bullae occurring on little or moderately emphysematous lung is often a simpler approach but also requires specialised support to optimize its results.

Actigraphic assessment of sleep in chronic obstructive pulmonary disease

PURPOSE

Previously, sleep in chronic obstructive pulmonary disease (COPD) has been objectively investigated only by lab-based polysomnography. The main purpose of this study was to evaluate sleep quality in COPD patients in their home environment using actigraphy. We also investigated the factors associated with sleep impairment and the relationship between objective and subjective sleep quality and daytime somnolence in these patients.

METHODS

Twenty-six patients with moderate to very severe COPD and 15 controls were studied by actigraphy for at least 5 days. Subjective sleep quality was evaluated by the Pittsburgh Sleep Quality Index and daytime sleepiness by the Epworth Sleepiness Scale (ESS). Dyspnea was quantified by the modified Medical Research Council (MMRC) scale.

RESULTS

COPD patients showed increased sleep latency (p = 0.003), mean activity (p = 0.003), and wake after sleep onset (p = 0.003) and reduced total sleep time (TST; p = 0.024) and sleep efficiency (p = 0.001), as compared to controls. In patients, severity of dyspnea was correlated with sleep activity (r = 0.41; p = 0.04) and TST (r = -0.46; p = 0.02) and multiple regression analysis showed that MMRC score was the best predictor of TST (p = 0.02) and sleep efficiency (p = 0.03). Actigraphy measures during daytime were not significantly different between patients and controls. Subjective sleep quality was poorer in patients than controls (p = 0.043). ESS scores were not significantly different between the two groups. Actigraphy measures were not correlated with subjective sleep quality or daytime somnolence in both groups.

CONCLUSIONS

Nocturnal sleep is markedly impaired in stable COPD patients studied by actigraphy in their home environment and this impairment is related to severity of dyspnea.

Several clinical interests regarding lung volume reduction surgery for severe emphysema: meta-analysis and systematic review of randomized controlled trials

Objectives

We aim to address several clinical interests regarding lung volume reduction surgery (LVRS) for severe emphysema using meta-analysis and systematic review of randomized controlled trials (RCTs).

Methods

Eight RCTs published from 1999 to 2010 were identified and synthesized to compare the efficacy and safety of LVRS vs conservative medical therapy. One RCT was obtained regarding comparison of median sternotomy (MS) and video-assisted thoracoscopic surgery (VATS). And three RCTs were available evaluating clinical efficacy of using bovine pericardium for buttressing, autologous fibrin sealant and BioGlue, respectively.

Results

Odds ratio (95%CI), expressed as the mortality of group A (the group underwent LVRS) versus group B (conservative medical therapies), was 5.16(2.84, 9.35) in 3 months, 3(0.94, 9.57) in 6 months, 1.05(0.82, 1.33) in 12 months, respectively. On the 3^rd, 6^th and 12^th month, all lung function indices of group A were improved more significantly as compared with group B. PaO2 and PaCO2 on the 6^th and 12^th month showed the same trend. 6MWD of group A on the 6^th month and 12^th month were improved significantly than of group B, despite no difference on the 3^rd month. Quality of life (QOL) of group A was better than of group B in 6 and 12 months. VATS is preferred to MS, due to the earlier recovery and lower cost. And autologous fibrin sealant and BioGlue seems to be the efficacious methods to reduce air leak following LVRS.

Conclusions

LVRS offers the more benefits regarding survival, lung function, gas exchange, exercise capacity and QOL, despite the higher mortality in initial three postoperative months. LVRS, with the optimization of surgical approach and material for reinforcement of the staple lines, should be recommended to patients suffering from severe heterogeneous emphysema.

The effects of sleep hypoxia on coagulant factors and hepatic inflammation in emphysematous rats

Objectives

To develop a sleep hypoxia (SH) in emphysema (SHE) rat model and to explore whether SHE results in more severe hepatic inflammation than emphysema alone and whether the inflammation changes levels of coagulant/anticoagulant factors synthesized in the liver.

Methods

Seventy-five rats were put into 5 groups: SH control (SHCtrl), treated with sham smoke exposure (16 weeks) and SH exposure (12.5% O₂, 3 h/d, latter 8 weeks); emphysema control (ECtrl), smoke exposure and sham SH exposure (21% O₂); short SHE (SHEShort), smoke exposure and short SH exposure (1.5 h/d); mild SHE (SHEMild), smoke exposure and mild SH exposure (15% O₂); standard SHE (SHEStand), smoke exposure and SH exposure. Therefore, ECtrl, SHEShort, SHEMild and SHEStand group were among emphysematous groups. Arterial blood gas (ABG) data was obtained during preliminary tests. After exposure, hepatic inflammation (interleukin -6 [IL-6] mRNA and protein, tumor necrosis factor α [TNFα] mRNA and protein) and liver coagulant/anticoagulant factors (antithrombin [AT], fibrinogen [FIB] and Factor VIII [F VIII]) were evaluated. SPSS 11.5 software was used for statistical analysis.

Results

Characteristics of emphysema were obvious in emphysematous groups and ABGs reached SH criteria on hypoxia exposure. Hepatic inflammation parameters and coagulant factors are the lowest in SHCtrl and the highest in SHEStand while AT is the highest in SHCtrl and the lowest in SHEStand. Inflammatory cytokines of liver correlate well with coagulant factors positively and with AT negatively.

Conclusions

When SH is combined with emphysema, hepatic inflammation and coagulability enhance each other synergistically and produce a more significant liver-derivative inflammatory and prothrombotic status.

Oxygen therapy for patients with COPD: current evidence and the long-term oxygen treatment trial

Long-term use of supplemental oxygen improves survival in patients with COPD and severe resting hypoxemia. However, the role of oxygen in symptomatic patients with COPD and more moderate hypoxemia at rest and desaturation with activity is unclear. The few long-term reports of supplemental oxygen in this group have been of small size and insufficient to demonstrate a survival benefit. Short-term trials have suggested beneficial effects other than survival in patients with COPD and moderate hypoxemia at rest. In addition, supplemental oxygen appeared to improve exercise performance in small short-term investigations of patients with COPD and moderate hypoxemia at rest and desaturation with exercise, but long-term trials evaluating patient-reported outcomes are lacking. This article reviews the evidence for long-term use of supplemental oxygen therapy and provides a rationale for the National Heart, Lung, and Blood Institute Long-term Oxygen Treatment Trial. The trial plans to enroll subjects with COPD with moderate hypoxemia at rest or desaturation with exercise and compare tailored oxygen therapy to no oxygen therapy.

Hyperinflation is associated with lower sleep efficiency in COPD with co-existent obstructive sleep apnea

Prior research has shown that individuals with obstructive lung disease are at risk for sleep fragmentation and poor sleep quality. We postulated that patients with chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (known as overlap syndrome) who have more severe lung disease, as measured by lung hyperinflation (inspiratory capacity/total lung capacity), would have greater sleep disturbances independent of traditional measures of sleep apnea. We performed a retrospective chart review of consecutive patients evaluated and treated in an academic pulmonary clinic for overlap syndrome. Pulmonary function tests and polysomnogram data were collected. Thirty patients with overlap syndrome were included in the analysis. We found significant univariable associations between sleep efficiency and apnea/hypopnea index (beta = -0.285, p = 0.01) and between sleep efficiency and lung hyperinflation (beta = 0.654, p = 0.03). Using multivariable linear regression, the relationship between sleep efficiency and lung hyperinflation remained significant (beta = 1.13, p = 0.02) after adjusting for age, sex, body mass index, apnea/hypopnea index, FEV(1)% predicted, oxygen saturation nadir, medications, and cardiac disease. We conclude that increased severity of hyperinflation is associated with worse sleep efficiency, independent of apnea and nocturnal hypoxemia. The mechanisms underlying this observation are uncertain. We speculate that therapies aimed at reducing lung hyperinflation may improve sleep quality in patients with overlap syndrome.

Lung volume reduction surgery for the management of refractory dyspnea in chronic obstructive pulmonary disease

PURPOSE OF REVIEW

This review describes the role of lung volume reduction surgery (LVRS) for the management of refractory dyspnea and other debilitating conditions in patients with chronic obstructive pulmonary disease. Recent studies, including a randomized trial comparing LVRS to medical therapy, are analyzed.

RECENT FINDINGS

LVRS plus optimal medical therapy is superior to medical therapy alone in treating certain subsets of patients with severe emphysema. In patients with predominantly upper lobe emphysema and low-exercise capacity, LVRS not only improves symptoms of dyspnea and exercise intolerance, but also is associated with improved survival. Furthermore, LVRS has recently been shown to be superior to medical therapy in improving other quality of life parameters, such as nutritional status, sleep quality, and the frequency of chronic obstructive pulmonary disease (COPD) exacerbations in patients with severe emphysema.

SUMMARY

LVRS is an effective strategy in the treatment of properly selected patients with COPD, improving survival and quality of life, including exercise tolerance, dyspnea, oxygen requirement and functional status.

Sleep and Obstructive Lung Diseases

Asthma and chronic obstructive pulmonary disease (COPD) are common obstructive lung diseases affecting millions of people in the United States. As sleep disorders are also common, it is not surprising that many people with obstructive lung disease also suffer from sleep disorders. However, people with COPD and those with asthma have worse sleep quality and more sleep-related problems when compared to people with other chronic health problems. In addition, a pathologic relationship may exist between obstructive sleep apnea (OSA) and obstructive lung diseases. This review focuses on the epidemiology, pathogenesis, and clinical implications of sleep disturbances in asthma and COPD.

Lung transplantation and lung volume reduction surgery versus transplantation in chronic obstructive pulmonary disease

Lung transplantation and lung volume reduction surgery are surgical options for patients with advanced chronic obstructive pulmonary disease that is refractory to medical treatment. In this review, we discuss the differential indications for each procedure, as well as compare their risks and benefits. We also present an algorithm for selecting the most appropriate procedure for individual patients. Finally, we discuss the feasibility and role of lung transplantation after lung volume reduction surgery in the management of selected patients with chronic obstructive pulmonary disease.

Sleep abnormalities and treatment in emphysema

Sleep abnormalities are common in severe emphysema, and include poor sleep quality, the development of nocturnal oxygen desaturation, and the presence of coexistent obstructive sleep apnea. With lower baseline oxygenation and abnormal respiratory mechanics in patients with severe emphysema, alterations in ventilatory control and respiratory muscle function that normally occur during sleep can have profound effects, and contribute to the development of sleep abnormalities. The impact on quality of life, cardiopulmonary hemodynamics, and overall survival remains uncertain. In addition, treatment for chronic obstructive pulmonary disease and its effect on sleep abnormalities have demonstrated conflicting results. More recently, as part of the National Emphysema Treatment Trial, lung volume reduction surgery has been shown to improve both sleep quality and nocturnal oxygenation in emphysema. Although indications for performing an overnight polysomnogram in patients with emphysema have been debated, recommendations have been presented. Future studies investigating disease mechanism and response to therapy in patients with sleep abnormalities and severe emphysema are warranted.

Oxygen therapy in chronic obstructive pulmonary disease

Since the introduction of oxygen as a therapeutic agent 70 years ago, much has been learned regarding the detrimental effects of hypoxemia and the beneficial impact of oxygen therapy. It is projected that there are close to 800,000 patients receiving long-term oxygen therapy (LTOT) in the United States, at a cost of approximately $1.8 billion annually. The large numbers of patients receiving supplemental oxygen as treatment and the high costs incurred in providing oxygen therapy necessitate the practitioner to know the indications for LTOT as well its effects on survival, pulmonary hemodynamics, sleep, and exercise capacity. It is now recognized that the basis for LTOT prescription for all patients is founded on data that are over 25 years old and that only involve a very select cohort of patients. It is clear that further studies are required to assess the effects of oxygen on patients with chronic obstructive pulmonary disease with only mild hypoxemia, not only survival but also on neurocognitive function, quality of life, exercise physiology, and sleep quality. In addition, although proven to be safe when prescribed long term to individuals with lung disease, there are some concerns about worsening carbon dioxide retention and increased oxidant injury. The goals of this article are to briefly describe the indications for chronic oxygen administration, the physiologic effects of treatment, and potential toxicities, as well as its effect on morbidity and mortality.

Respiratory disorders during sleep in chronic obstructive pulmonary disease

Patients with COPD may show slow, progressive deteriorations in arterial blood gases during the night, particularly during rapid eye movement (REM) sleep. This is mainly due to hypoventilation, while a deterioration of ventilation/perfusion mismatch plays a minor role. The severity of gas exchanges alterations is proportional to the degree of impairment of diurnal pulmonary function tests, particularly of partial pressure of oxygen (PaO₂) and of carbon dioxide (PaCO₂) in arterial blood, but correlations between diurnal and nocturnal blood gas levels are rather loose. Subjects with diurnal PaO₂ of 60–70 mmHg are distinguished in “desaturators” and “nondesaturators” according to nocturnal oxyhemoglobin saturation behavior. The role of nocturnal hypoxemia as a determinant of alterations in sleep structure observed in COPD is dubious. Effects of the “desaturator” condition on pulmonary hemodynamics, evolution of diurnal blood gases, and life expectancy are also controversial. Conversely, it is generally accepted that occurrence of sleep apneas in COPD is associated with a worse evolution of the disease. Nocturnal polysomnographic monitoring in COPD is usually performed when coexistence of sleep apnea (“overlap syndrome”) is suspected, while in most other cases nocturnal oximetry may be enough. Nocturnal oxygen attenuates sleep desaturations among stable patients, without increases in PaCO₂ of clinical concern. Nocturnal treatment with positive pressure ventilators may give benefit to some stable hypercapnic subjects and patients with the overlap syndrome.

Lung volume reduction surgery for diffuse emphysema

BACKGROUND

Lung volume reduction surgery (LVRS) has been re-introduced for treating patients with severe diffuse emphysema. It is a procedure that aims to improve long-term daily functioning, although it is costly and may also be associated with a high risk of mortality.

OBJECTIVES

To assemble evidence from randomised controlled trials for the effectiveness of LVRS, and identify optimal surgical techniques.

SEARCH STRATEGY

Randomised controlled trials were identified using the Cochrane Airways Group Chronic Obstructive Pulmonary Disease (COPD) register. Searches are current to September 2005.

SELECTION CRITERIA

Randomised controlled trials that studied the safety and efficacy of LVRS in patients with diffuse emphysema were included. Studies were excluded if they investigated giant or bullous emphysema.

DATA COLLECTION AND ANALYSIS

Two independent review authors assessed trials for inclusion and extracted data. Where possible, data from more than one study were combined using RevMan 4.2 software.

MAIN RESULTS

Eight studies (1663 participants) met the entry criteria of the review. One study accounted for 73% of the participants recruited. Study quality was high, although blinding in studies was not possible. Ninety day mortality was significantly greater in all those who underwent LVRS (odds ratio 6.57 (95% CI 3.34 to 12.95), four studies, N = 1415). A subgroup analysis by risk status suggested that there was a subgroup of participants who were consistently at a significant risk of death, although this was only measured in one large study. The ninety day mortality data indicated that death was more likely with LVRS irrespective of risk status identified in one large study. Improvements in lung function, quality of life and exercise capacity were more likely with LVRS than with usual follow-up.

AUTHORS' CONCLUSIONS

The evidence summarised in this review is drawn from one large study, and several smaller trials. The findings from the large study indicated that in patients who survive up to three months post-surgery, there were significantly better health status and lung function outcomes in favour of surgery compared with usual medical care. Patients identified post hoc as being of high risk of death from surgery were those with particularly impaired lung function and poor diffusing capacity and/or homogenous emphysema. Further research should address the effect of this intervention on exacerbations and rate of decline in lung function and health status.