Central Airway Obstruction: Benign Strictures, Tracheobronchomalacia, and Malignancy-related Obstruction

Objectives: Dynamic flexible bronchoscopy is the “gold standard” for assessing changes in airway luminal size associated with tracheobronchomalacia, but the procedure has not been adequately validated. The present study was designed to test the validity of diagnosing tracheobronchomalacia by dynamic flexible bronchoscopy through assessing inter- and intraobserver agreements in estimating degree of central airway collapse associated with tracheobronchomalacia.Methods: This prospective observational pilot study enrolled consecutive patients with suspected tracheobronchomalacia scheduled for dynamic flexible bronchoscopy. Images of the airway lumen were obtained at five different sites in the tracheobronchial tree during forced inspiration and expiration and were evaluated by 23 pulmonologists (not involved in the care of study patients) with different levels of training and experience at baseline (interobserver agreement) and 8 days later (intraobserver agreement). The degree of airway collapse was visually...

Evaluation of Tracheobronchomalacia by Dynamic Flexible Bronchoscopy. A Pilot Study

The impact of alcohol on breathing parameters during sleep: A systematic review and meta-analysis

Background COPD patients who develop chronic hypercapnic respiratory failure have a poor prognosis. Treatment of choice, especially the best form of ventilation, is not well known. Objectives This study compared the effects of pressure-controlled (spontaneous timed [ST]) non-invasive ventilation (NIV) and NIV with intelligent volume-assured pressure support (IVAPS) in chronic hypercapnic COPD patients regarding the effects on alveolar ventilation, adverse patient/ventilator interactions and sleep quality. Methods This prospective, single-center, crossover study randomized patients to one night of NIV using ST then one night with the IVAPS function activated, or vice versa. Patients were monitored using polysomnography (PSG) and transcutaneous carbon dioxide pressure (PtcCO2) measurement. Patients rated their subjective experience (total score, 0-45; lower scores indicate better acceptability). Results Fourteen patients were included (4 females, age 59.4±8.9 years). The total number of respiratory events was low, and similar under pressure-controlled (5.4±6.7) and IVAPS (8.3±10.2) conditions (P=0.064). There were also no clinically relevant differences in PtcCO2 between pressure-controlled and IVAPS NIV (52.9±6.2 versus 49.1±6.4 mmHg). Respiratory rate was lower under IVAPS overall; between-group differences reached statistical significance during wakefulness and non-rapid eye movement sleep. Ventilation pressures were 2.6 cmH2O higher under IVAPS versus pressure-controlled ventilation, resulting in a 20.1 mL increase in breathing volume. Sleep efficiency was slightly higher under pressure-controlled ventilation versus IVAPS. Respiratory arousals were uncommon (24.4/h [pressure-controlled] versus 25.4/h [IVAPS]). Overall patient assessment scores were similar, although there was a trend toward less discomfort during IVAPS. Conclusion Our results show that IVAPS NIV allows application of higher nocturnal ventilation pressures versus ST without affecting sleep quality or inducing ventilation- associated events.

/pdf/non-invasive-ventilation-with-intelligent-volume-assured-1r6dhctaf1.pdf

Non-invasive ventilation with intelligent volume-assured pressure support versus pressure-controlled ventilation: effects on the respiratory event rate and sleep quality in COPD with chronic hypercapnia.

Objectives Patients with asthma–chronic obstructive pulmonary disease (COPD) overlap syndrome (ACOS) and cardiovascular diseases (CVDs) share common risk factors. However, the association between ACOS and the incidence of CVDs has not been reported. This study investigated the relationship between CVDs and ACOS in the general population. Setting Data were obtained from Taiwan’s National Health Insurance Research Database for the period 2000 to 2010. Participants The ACOS cohort comprised patients (n=5814) who had received a diagnosis of asthma and COPD. The non-ACOS cohort comprised patients who had not received a diagnosis of asthma or COPD and were matched to the ACOS cohort (2:1) by age, sex and index date (n=11 625). Primary and secondary outcome measures The cumulative incidence of CVDs—coronary artery disease (CAD), cardiac dysrhythmia (CD) and heart failure (HF)—was calculated. Cox proportional regression analysis was employed to examine the relationship between ACOS and CVDs. Results After adjustment for multiple confounding factors—age, sex, comorbidities and medications—patients with ACOS were associated with a significantly higher risk of CVDs; the adjusted HRs (aHRs; 95% CI) for CAD, CD and HF were 1.62 (1.50 to 1.76), 1.44 (1.30 to 1.61) and 1.94 (1.73 to 2.19), respectively, whereas those of beta-blockers treatment for CAD, CD and HF were 1.19 (0.92 to 1.53), 0.90 (0.56 to 1.45) and 0.82 (0.49 to 1.38). The aHR of atenolol treatment for CD was 1.72 (1.01 to 2.93). The aHRs (95% CIs) of ACOS without acute exacerbation of COPD (AE-COPD) for CAD, CD and HF were 1.85 (1.70 to 2.01), 1.57 (1.40 to 1.77) and 2.07 (1.82 to 2.35), respectively. Conclusion ACOS was associated with higher CVD risk, even without the presence of previous comorbidities or AE-COPD. No significant differences in CVD events were observed in the ACOS cohort using beta-blockers, except for those using atenolol for treating CD.

https://bmjopen.bmj.com/content/bmjopen/7/10/e017657.full.pdf

Association of asthma-chronic obstructive pulmonary disease overlap syndrome with coronary artery disease, cardiac dysrhythmia and heart failure: a population-based retrospective cohort study.

Purpose
To explore the associations between sleep hypoventilation (SH) and daytime arterial pressures of carbon dioxide (PaCO2), sleep stages, and sleep apneas/hypopneas (AHI) in subjects with chronic obstructive pulmonary disease (COPD). SH has previously been found in COPD-subjects with chronic hypercapnic respiratory failure (CHRF) using supplementary oxygen (LTOT), and has been proposed as a possible predictor for CHRF.

Sleep hypoventilation and daytime hypercapnia in stable chronic obstructive pulmonary disease

Background:Excessive dynamic airway collapse (EDAC) represents pathologic obstruction, but the flow resistance it creates and the possible impact on pulmonary function tests is unclear. Our aims were to explore the flow resistance in a model, and in patients to relate observed EDAC to pulmonary func

Does excessive dynamic airway collapse have any impact on dynamic pulmonary function tests

More than half of patients with chronic obstructive pulmonary disease (COPD) experiences sleep-related problems and about one fourth uses hypnotics regularly. We explored what the effect zopiclone, a commonly used hypnotic, had on nocturnal gas exchange and the apnea/hypopnea frequency in stable COPD. Randomized crossover study of 31 (ten males) inpatients at a pulmonary rehabilitation hospital, median age 64 years, of which 20 had a forced expiratory volume first second <50 % of predicted. Subjects investigated in randomized order of either baseline sleep or intervention with 5 mg zopiclone by polysomnography including transcutaneous measurement of carbon dioxide pressure increased (ΔPtcCO2). Zopiclone increased the mean ΔPtcCO2 from baseline both in rapid eye movement (REM) sleep, non-REM sleep, and even in stage N0 (awake after sleep onset) with a mean (SD) of 0.25 (0.40) kPa, 0.22 (0.32) kPa, and 0.14 (0.27) kPa, respectively. Subjects with sleep hypoventilation as defined by the American Academy of Sleep Medicine increased from 6 subjects (19 %) to 13 subjects (42 %) (P = 0.020). REM sleep minimum oxygen saturation (minSpO2) did not change significantly from baseline median (interquartile range [IQR]) minSpO2 81.8 (12.1) % to zopiclone sleep median (IQR) minSpO2 80.0 (12.0) % (P = 0.766). Interestingly, zopiclone reduced the number of apneas/hypopneas per hour (AHI) in subjects with overlap (AHI ≥ 15) with a median difference (IQR) of −8.5 (7.8) (N = 11, P = 0.016). In stable COPD, zopiclone moderately increases the mean ΔPtcCO2 without changing minSpO2 at night and reduces AHI in overlap (COPD and obstructive sleep apnea) subjects.

/pdf/zopiclone-effects-on-breathing-at-sleep-in-stable-chronic-4saa1p40ya.pdf

Zopiclone effects on breathing at sleep in stable chronic obstructive pulmonary disease

Purpose/background
The purpose of this study is to explore the effect of a moderate dose of alcohol on sleep architecture and respiration in chronic obstructive pulmonary disease (COPD). Alcohol depresses both hypercapnic and hypoxic ventilatory drives in awake, normal individuals and reduces the amount of rapid eye movement (REM) sleep and oxygen saturation (SpO2) in sleeping COPD subjects.

/pdf/alcohol-at-bedtime-induces-minor-changes-in-sleep-stages-and-14evu7j9vv.pdf

Alcohol at bedtime induces minor changes in sleep stages and blood gases in stable chronic obstructive pulmonary disease

An increase in PaCO2 is the element that defines sleep hypoventilation (SH). We queried if patients with SH, and those with PaCO2 increases during sleep for shorter time periods than SH (shamSH) differed from the patients without SH (noSH) in other ways. This was a retrospective re-analysis of data from 100 stable inpatients with COPD with and without chronic hypercapnic respiratory failure. COPD was defined by criteria of the Global initiative for Chronic Obstructive Lung Disease (GOLD). For this study, SH was defined by an increase in PaCO2 ≥ 1.33 kPa to a value exceeding 6.7 kPa for ≥ 10 min (≥ 20 epochs of 30 s). Patients fulfilling the increase in PaCO2 for less than 10 min (1–19 epochs) were designated shamSH. All patients had daytime arterial blood gases, lung function tests, and polysomnography (PSG) with transcutaneous CO2 (PtcCO2). Of 100 patients, 25 had PtcCO2 increase ≥ 1.33 kPa. One never exceeded 6.7 kPa, 15 had SH, and 9 shamSH. SH and shamSH patients had extra CO2 load (= PtcCO2*time) both during and between the SH periods compared to the noSH group, the SH group more than the shamSH group. Using CO2 load as a measure of severity of sleep hypoventilation, SH patients have worse hypoventilation than the shamSH. Both shamSH and SH groups have extra CO2 load during and between SH periods, indicating that the SH/shamSH patients may represent a separate group of true hypoventilators during sleep.

Nils Henrik Holmedahl

Papers

Sleep hypoventilation and daytime hypercapnia in stable chronic obstructive pulmonary disease

Does excessive dynamic airway collapse have any impact on dynamic pulmonary function tests

Zopiclone effects on breathing at sleep in stable chronic obstructive pulmonary disease

Alcohol at bedtime induces minor changes in sleep stages and blood gases in stable chronic obstructive pulmonary disease

The severity of sleep hypoventilation in stable chronic obstructive pulmonary disease