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  • 1
    Language: English
    In: Scientific reports, 2021-10-13, Vol.11 (1), p.20355-20355
    Description: AbstractThis trial evaluates whether nocturnal oxygen therapy (NOT) during a stay at 2048 m improves altitude-induced exercise intolerance in lowlanders with chronic obstructive pulmonary disease (COPD). 32 lowlanders with moderate to severe COPD, mean ± SD forced expiratory volume in the first second of expiration (FEV1) 54 ± 13% predicted, stayed for 2 days at 2048 m twice, once with NOT, once with placebo according to a randomized, crossover trial with a 2-week washout period at 〈 800 m in-between. Semi-supine, constant-load cycle exercise to exhaustion at 60% of maximal work-rate was performed at 490 m and after the first night at 2048 m. Endurance time was the primary outcome. Additional outcomes were cerebral tissue oxygenation (CTO), arterial blood gases and breath-by-breath measurements (http://www.ClinicalTrials.gov NCT02150590). Mean ± SE endurance time at 490 m was 602 ± 65 s, at 2048 m after placebo 345 ± 62 s and at 2048 m after NOT 293 ± 60 s, respectively (P 〈 0.001 vs. 490 m). Mean difference (95%CI) NOT versus placebo was − 52 s (− 174 to 70), P = 0.401. End-exercise pulse oximetry (SpO2), CTO and minute ventilation ($${\dot{\text{V}}}_{{\text{E}}}$$ V ˙ E ) at 490 m were: SpO2 92 ± 1%, CTO 65 ± 1%, $${\dot{\text{V}}}_{{\text{E}}}$$ V ˙ E 37.7 ± 2.0 L/min; at 2048 m with placebo: SpO2 85 ± 1%, CTO 61 ± 1%, $${\dot{\text{V}}}_{{\text{E}}}$$ V ˙ E  40.6 ± 2.0 L/min and with NOT: SpO2 84 ± 1%; CTO 61 ± 1%; $${\dot{\text{V}}}_{{\text{E}}}$$ V ˙ E  40.6 ± 2.0 L/min (P 〈 0.05, SpO2, CTO at 2048 m with placebo vs. 490 m; P = NS, NOT vs. placebo). Altitude-related hypoxemia and cerebral hypoxia impaired exercise endurance in patients with moderate to severe COPD and were not prevented by NOT.
    Subject(s): Altitude ; Chronic obstructive pulmonary disease ; Hypoxemia ; Hypoxia ; Intolerance ; Lung diseases ; Obstructive lung disease ; Oxygen ; Oxygen therapy ; Oxygenation ; Patients ; Placebos ; Ventilation
    ISSN: 2045-2322
    E-ISSN: 2045-2322
    Source: Nature Open Access
    Source: Academic Search Ultimate
    Source: PubMed Central
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  • 2
    Language: English
    In: Chest, 2005-09, Vol.128 (3), p.1282-1290
    Description: To evaluate the accuracy of a portable respiratory inductive plethysmograph that allows the monitoring of ventilation without airway instrumentation during exercise in unrestrained subjects. Validation of a novel technique by comparison to a reference standard. Thirty-one subjects, including 20 healthy volunteers, 6 patients with COPD, and 5 patients with congestive heart failure. Participants performed progressive treadmill exercise to exhaustion. Ventilation was monitored by a novel battery-powered, miniaturized, and calibrated respiratory inductive plethysmograph. Inductance sensors encircling the rib cage and abdomen were built into an elastic body garment. A pneumotachograph attached to a mouthpiece served as the reference method. Breath-by-breath comparisons between the inductance plethysmograph and pneumotachograph over the course of progressive exercise to exhaustion revealed no significant bias of respiratory cycle time, tidal volume (Vt), and minute ventilation. The corresponding limits of agreement (bias ± 2 SDs) were ± 6%, ±17%, and ± 17%, respectively, for 2,480 breaths. Comparisons of mean values averaged over 20 breaths revealed improved limits of agreement of ± 1% for cycle time, and ± 7% for tidal volume and minute ventilation, respectively, for 124 comparisons. Agreement between methods was similar for patients and healthy subjects. Among the patients, maximal minute ventilation was lower, and breathing was more rapid and shallow than in healthy subjects. Obstructive lung disease was associated with a shorter duty cycle than heart failure. The portable respiratory inductive plethysmograph accurately estimates ventilation during treadmill exercise, and identifies differences in breathing patterns among patients with pulmonary or cardiac diseases and healthy subjects. This unobtrusive monitoring technique is promising for application in ambulatory patients.
    Subject(s): Abridged Index Medicus ; Adult ; Analysis ; breathing pattern ; Care and treatment ; Diagnosis ; Exercise ; Exercise Test ; Female ; Health aspects ; Heart Failure - physiopathology ; Humans ; inductive plethysmography ; Lung diseases ; Male ; Monitoring, Physiologic - instrumentation ; noninvasive physiologic monitoring ; Plethysmography ; Plethysmography - instrumentation ; Pulmonary Disease, Chronic Obstructive - physiopathology ; pulmonary ventilation ; Reference Standards ; Respiratory Mechanics - physiology
    ISSN: 0012-3692
    E-ISSN: 1931-3543
    Source: Academic Search Ultimate
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  • 3
    Article
    Article
    2011
    ISSN: 0140-6736 
    Language: English
    In: The Lancet (British edition), 2011, Vol.378 (9795), p.1048-1048
    Description: Byline: Daniel Franzen (a), Konrad E Bloch (a) Author Affiliation: (a) Department of Pneumology, University Hospital of Zurich, Zurich, Switzerland
    Subject(s): Abridged Index Medicus ; Adult ; Alveolitis, Extrinsic Allergic - diagnosis ; Alveolitis, Extrinsic Allergic - diagnostic imaging ; Biological and medical sciences ; Dyspnea ; Fever - etiology ; General aspects ; Humans ; Internal Medicine ; Lung - diagnostic imaging ; Male ; Medical sciences ; Tomography, X-Ray Computed
    ISSN: 0140-6736
    E-ISSN: 1474-547X
    Source: Backfile Package - All of Back Files EBS [ALLOFBCKF]
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  • 4
    Language: English
    In: Chest, 2005-09, Vol.128 (3), p.1291-1296
    Description: The purpose of the study was to evaluate a novel, combined sensor for transcutaneous monitoring of arterial oxygen saturation and carbon dioxide tension. The new monitoring technique was compared to established reference methods. ICU and sleep laboratory of a university hospital. Eighteen critically ill adult patients with acute respiratory failure or heart failure, and 12 patients with sleep apnea (mean [± SD] apnea/hypopnea index, 43 ± 24 events per hour). Continuous measurements were performed over several hours by the novel heated (temperature, 42°C) earlobe sensor (TOSCA; Linde Medical Sensors; Basel, Switzerland), incorporating electrochemical and optical elements for carbon dioxide measurement (PtcCO2) and pulse oximetry (SpO2), respectively. The data were compared to the results of repeated arterial blood gas analyses in critically ill patients and to simultaneous nocturnal pulse oximetry performed with different devices with earlobe or finger sensors in sleep apnea patients. In critically ill patients, the mean difference and limits of agreement (bias ± 2 SDs) of transcutaneous PtcCO2 vs arterial PaCO2 were 3 ± 7 mm Hg; the corresponding values for changes in PtcCO2 vs PaCO2 were 1 ± 6 mm Hg. The bias ± 2 SDs for pulse oximetric SpO2 vs arterial oxygen saturation (SaO2) were 1 ± 4%. In sleep apnea patients, the combined earlobe sensor identified more transient oxygen desaturations, and the rate of change in oxygen saturation during events was greater compared to those with other tested pulse oximeters, indicating a faster response. Due to its ability to accurately assess both ventilation and oxygenation by a single transcutaneous sensor, the described noninvasive monitoring technique is a valuable tool for respiratory monitoring with potential applications in critical care and sleep medicine.
    Subject(s): Abridged Index Medicus ; Acute Disease ; Aged ; Blood Gas Monitoring, Transcutaneous - instrumentation ; capnometry ; carbon dioxide ; Care and treatment ; Case studies ; critical care ; Critical Illness ; Critically ill ; Diagnosis ; Humans ; Middle Aged ; Myocardial Infarction - complications ; oxygenation ; physiologic monitoring ; pulse oximetry ; Respiration, Artificial ; Respiratory Insufficiency - diagnosis ; Respiratory Insufficiency - etiology ; Respiratory Insufficiency - therapy ; sleep apnea ; Sleep apnea syndromes ; Sleep Apnea, Obstructive - complications ; sleep medicine ; ventilation
    ISSN: 0012-3692
    E-ISSN: 1931-3543
    Source: Academic Search Ultimate
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  • 5
    Language: English
    In: Journal of Applied Physiology, 2009-02-01, Vol.106 (2), p.454-460
    Description: Little is known about the ocular and cerebral blood flow during exposure to increasingly hypoxic conditions at high altitudes. There is evidence that an increase in cerebral blood flow resulting from altered autoregulation constitutes a risk factor for acute mountain sickness (AMS) and high-altitude cerebral edema (HACE) by leading to capillary overperfusion and vasogenic cerebral edema. The retina represents the only part of the central nervous system where capillary blood flow is visible and can be measured by noninvasive means. In this study we aimed to gain insights into retinal and choroidal autoregulatory properties during hypoxia and to correlate circulatory changes to symptoms of AMS and clinical signs of HACE. This observational study was performed within the scope of a high-altitude medical research expedition to Mount Muztagh Ata (7,546 m). Twenty seven participants underwent general and ophthalmic examinations up to a maximal height of 6,800 m. Examinations included fundus photography and measurements of retinal and choroidal blood flow, as well as measurement of arterial oxygen saturation and hematocrit. The initial increase in retinal blood velocity was followed by a decrease despite further ascent, whereas choroidal flow increase occurred later, at even higher altitudes. The sum of all adaptational mechanisms resulted in a stable oxygen delivery to the retina and the choroid. Parameters reflecting the retinal circulation and optic disc swelling correlated well with the occurrence of AMS-related symptoms. We demonstrate that sojourns at high altitudes trigger distinct behavior of retinal and choroidal blood flow. Increase in retinal but not in choroidal blood flow correlated with the occurrence of AMS-related symptoms.
    Subject(s): Acclimatization ; Adaptation, Physiological ; Adult ; Altitude ; Altitude Sickness - physiopathology ; Biological and medical sciences ; Blood Flow Velocity ; Blood Pressure ; Cerebrovascular Circulation ; Choroid - blood supply ; Female ; Fluorescein Angiography ; Fundamental and applied biological sciences. Psychology ; Hematocrit ; Homeostasis ; Humans ; Hypoxia - physiopathology ; Intraocular Pressure ; Laser-Doppler Flowmetry ; Logistic Models ; Male ; Middle Aged ; Odds Ratio ; Oxygen - blood ; Prospective Studies ; Regional Blood Flow ; Retinal Vessels - diagnostic imaging ; Retinal Vessels - physiopathology ; Risk Assessment ; Switzerland ; Time Factors ; Ultrasonography ; Visual Acuity
    ISSN: 8750-7587
    E-ISSN: 1522-1601
    Source: Alma/SFX Local Collection
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  • 6
    Language: English
    In: American journal of respiratory and critical care medicine, 2011, Vol.184 (10), p.1192-1199
    Description: To establish a new approach to investigate the physiological effects of obstructive sleep apnea (OSA), and to evaluate novel treatments, during a period of continuous positive airway pressure (CPAP) withdrawal. To determine the effects of CPAP withdrawal. Forty-one patients with OSA and receiving CPAP were randomized to either CPAP withdrawal (subtherapeutic CPAP), or continued CPAP, for 2 weeks. Polysomnography, sleepiness, psychomotor performance, endothelial function, blood pressure (BP), heart rate (HR), urinary catecholamines, blood markers of systemic inflammation, and metabolism were assessed. CPAP withdrawal led to a recurrence of OSA within a few days and a return of subjective sleepiness, but was not associated with significant deterioration of psychomotor performance within 2 weeks. Endothelial function, assessed by flow-mediated dilatation, decreased significantly in the CPAP withdrawal group compared with therapeutic CPAP (mean difference in change, -3.2%; 95% confidence interval [CI], -4.5, -1.9%; P 〈 0.001). Compared with continuing CPAP, 2 weeks of CPAP withdrawal was associated with a significant increase in morning systolic BP (mean difference in change, +8.5 mm Hg; 95% CI, +1.7, +15.3 mm Hg; P = 0.016), morning diastolic BP (mean difference in change, +6.9 mm Hg; 95% CI, +1.9, +11.9 mm Hg; P = 0.008), and morning HR (mean difference in change, +6.3 bpm, 95% CI, +0.4, +12.2 bpm; P = 0.035). CPAP withdrawal was associated with an increase in urinary catecholamines but did not lead to an increase in markers of systemic inflammation, insulin resistance, or blood lipids. CPAP withdrawal usually leads to a rapid recurrence of OSA, a return of subjective sleepiness, and is associated with impaired endothelial function, increased urinary catecholamines, blood pressure, and heart rate. Thus the proposed study model appears to be suitable to evaluate physiological and therapeutic effects in OSA. Clinical trial registered with www.controlled-trials.com (ISRCTN93153804).
    Subject(s): Abridged Index Medicus ; Actigraphy ; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy ; Biological and medical sciences ; Biomarkers - blood ; Blood Pressure - physiology ; Continuous Positive Airway Pressure - methods ; Disorders of Excessive Somnolence - etiology ; Emergency and intensive respiratory care ; Endothelium, Vascular - physiopathology ; Female ; Heart Rate - physiology ; Humans ; Inflammation - blood ; Insulin Resistance - physiology ; Intensive care medicine ; Male ; Medical sciences ; Middle Aged ; Polysomnography ; Psychomotor Performance ; Recurrence ; Sleep Apnea, Obstructive - physiopathology ; Sleep Apnea, Obstructive - therapy
    ISSN: 1073-449X
    E-ISSN: 1535-4970
    Source: ProQuest Central
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  • 7
    Language: English
    In: The European respiratory journal, 2017, Vol.49 (1), p.1600959
    Description: The complexity of central breathing disturbances during sleep has become increasingly obvious. They present as central sleep apnoeas (CSAs) and hypopnoeas, periodic breathing with apnoeas, or irregular breathing in patients with cardiovascular, other internal or neurological disorders, and can emerge under positive airway pressure treatment or opioid use, or at high altitude. As yet, there is insufficient knowledge on the clinical features, pathophysiological background and consecutive algorithms for stepped-care treatment. Most recently, it has been discussed intensively if CSA in heart failure is a "marker" of disease severity or a "mediator" of disease progression, and if and which type of positive airway pressure therapy is indicated. In addition, disturbances of respiratory drive or the translation of central impulses may result in hypoventilation, associated with cerebral or neuromuscular diseases, or severe diseases of lung or thorax. These statements report the results of an European Respiratory Society Task Force addressing actual diagnostic and therapeutic standards. The statements are based on a systematic review of the literature and a systematic two-step decision process. Although the Task Force does not make recommendations, it describes its current practice of treatment of CSA in heart failure and hypoventilation.
    Subject(s): ADAPTIVE SERVO-VENTILATION ; Advisory Committees ; AMYOTROPHIC-LATERAL-SCLEROSIS ; Analgesics, Opioid - therapeutic use ; CHEYNE-STOKES RESPIRATION ; CHRONIC HEART-FAILURE ; DUCHENNE MUSCULAR-DYSTROPHY ; Europe ; Humans ; Hypoventilation - etiology ; INTERSTITIAL LUNG-DISEASE ; OBESITY-HYPOVENTILATION SYNDROME ; Polysomnography ; POSITIVE AIRWAY PRESSURE ; Positive-Pressure Respiration ; Practice Guidelines as Topic ; QUALITY-OF-LIFE ; RANDOMIZED CONTROLLED-TRIAL ; Review Literature as Topic ; Sleep ; Sleep Apnea, Central - diagnosis ; Sleep Apnea, Central - physiopathology ; Sleep Apnea, Central - therapy
    ISSN: 0903-1936
    E-ISSN: 1399-3003
    Source: HighWire Press (Free Journals)
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  • 8
    Language: English
    In: Journal of Applied Physiology, 2006-12-01, Vol.101 (6), p.1760-1765
    Description: Whether nasal obstruction disturbs sleep and nocturnal breathing is controversial because convenient techniques for measuring nasal resistance during sleep are lacking. Therefore, we developed a technique for unobtrusive, side-selective nasal conductance monitoring. The technique measures left and right nasal airflow and transnasal pressure using nasal cannulas, thin catheters inserted through the cannulas into the nasopharynx, and three pressure transducers. Their processed signals provide conductance as airflow-to-resistive pressure ratio for the left and right side and the sum, total nasal conductance. For validation, total nasal conductance was also determined by a flowmeter attached to a nasal mask and nasopharyngeal pressure that served as reference standard. Methods were compared in five normal subjects during pharmacological interventions and in 12 snorers during sleep. The novel technique accurately tracked total nasal conductance by the reference method at baseline, after nasal application of histamine and xylomethazoline in normal subjects; mean difference (bias) was 1%, and limits of agreement (±2 SD of bias) were ± 22% (75 comparisons). Corresponding values during overnight sleep studies in snorers were 0 ± 19% (192 comparisons); bias and limits of agreement of changes in nasal conductance were 1 ± 19% (180 comparisons). Conductance measured once at the beginning of sleep studies differed from subsequent measurements during the night by a mean ± SD of 26 ± 20%, P 〈 0.0001. The novel technique accurately measures side-selective conductance. It is suitable to investigate interactions among nasal obstruction, sleep and nocturnal breathing, and drug effects. One-time measurements at the beginning of sleep studies do not appropriately reflect the highly variable nasal conductance during an entire night.
    Subject(s): Adult ; Biological and medical sciences ; Catheterization - instrumentation ; Catheterization - methods ; Equipment Design ; Equipment Failure Analysis ; Female ; Fundamental and applied biological sciences. Psychology ; Humans ; Male ; Middle Aged ; Monitoring, Physiologic - instrumentation ; Monitoring, Physiologic - methods ; Nasal Cavity - physiopathology ; Nasal Obstruction - diagnosis ; Nasal Obstruction - physiopathology ; Reproducibility of Results ; Rhinomanometry - instrumentation ; Rhinomanometry - methods ; Sensitivity and Specificity ; Sleep Apnea Syndromes - diagnosis ; Sleep Apnea Syndromes - physiopathology
    ISSN: 8750-7587
    E-ISSN: 1522-1601
    Source: Alma/SFX Local Collection
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  • 9
    Language: English
    In: Thorax, 2019-04, Vol.74 (4), p.390-396
    Description: BackgroundThe Epworth Sleepiness Scale (ESS) is a widely used tool for assessing sleepiness in patients with obstructive sleep apnoea (OSA). We aimed to estimate the minimal important difference (MID) in patients with OSA.MethodsWe used individual data from three randomised controlled trials (RCTs) in patients with OSA where the preintervention to postintervention change in ESS was used as a primary outcome. We used anchor-based linear regression and responder analysis approaches to estimate the MID. For anchors, we used the change in domains of the Functional Outcomes of Sleep Questionnaire and 36-Item Short Form Health Survey. We also used the distribution-based approaches Cohen’s effect size, SE of measurement and empirical rule effect size to support the anchor-based estimates. The final MID was determined by triangulating all estimates to a single MID.FindingsA total of 639 patients with OSA were included in our analyses across the three RCTs with a median (IQR) baseline ESS score of 10 (6–13). The median (IQR) ESS change score overall was −2 (−5 to 1). The anchor-based estimates of the MID were between −1.74 and −4.21 points and estimates from the responder analysis were between −1 and −3 points. Distribution-based estimates were smaller, ranging from −1.46 to −2.36.InterpretationWe propose an MID for the ESS of 2 points in patients with OSA with a disease severity from mild to severe. This estimate provides the means to plan trials and interpret the clinical relevance of changes in ESS.Trial registration numberProvent, NCT01332175; autoCPAP trial, NCT00280800; MOSAIC,ISRCTN (3416388).
    Subject(s): Arthritis ; Chronic obstructive pulmonary disease ; Clinical medicine ; Health surveys ; Life Sciences & Biomedicine ; Patients ; Quality of life ; Respiratory System ; Science & Technology ; Sleep apnea ; Sleep deprivation ; Validity
    ISSN: 0040-6376
    E-ISSN: 1468-3296
    Source: Web of Science - Science Citation Index Expanded - 2019〈img src="http://exlibris-pub.s3.amazonaws.com/fromwos-v2.jpg" /〉
    Source: Alma/SFX Local Collection
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  • 10
    Language: English
    In: Journal of applied physiology (1985), 2015-12-15, Vol.119 (12), p.1466-1480
    Description: Lowlanders commonly report a poor sleep quality during the first few nights after arriving at high altitude. Polysomnographic studies reveal that reductions in slow wave sleep are the most consistent altitude-induced changes in sleep structure identified by visual scoring. Quantitative spectral analyses of the sleep electroencephalogram have confirmed an altitude-related reduction in the low-frequency power (0.8-4.6 Hz). Although some studies suggest an increase in arousals from sleep at high altitude, this is not a consistent finding. Whether sleep instability at high altitude is triggered by periodic breathing or vice versa is still uncertain. Overnight changes in slow wave-derived encephalographic measures of neuronal synchronization in healthy subjects were less pronounced at moderately high (2,590 m) compared with low altitude (490 m), and this was associated with a decline in sleep-related memory consolidation. Correspondingly, exacerbation of breathing and sleep disturbances experienced by lowlanders with obstructive sleep apnea during a stay at 2,590 m was associated with poor performance in driving simulator tests. These findings suggest that altitude-related alterations in sleep may adversely affect daytime performance. Despite recent advances in our understanding of sleep at altitude, further research is required to better establish the role of gender and age in alterations of sleep at different altitudes, to determine the influence of acclimatization and of altitude-related illness, and to uncover the characteristics of sleep in highlanders that may serve as a study paradigm of sleep in patients exposed to chronic hypoxia due to cardiorespiratory disease.
    Subject(s): Altitude ; Animals ; Humans ; Hypoxia - etiology ; Hypoxia - physiopathology ; Sleep - physiology ; Sleep Initiation and Maintenance Disorders - etiology ; Sleep Initiation and Maintenance Disorders - physiopathology ; Sleep Initiation and Maintenance Disorders - psychology
    ISSN: 8750-7587
    E-ISSN: 1522-1601
    Source: Alma/SFX Local Collection
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