Nocturnal Oxygen Therapy Research Articles

P477 How the use of nocturnal non-invasive ventilation and oxygen therapy changes in patients with cystic fibrosis using elexacaftor/tezacaftor/ivacaftor

P477 How the use of nocturnal non-invasive ventilation and oxygen therapy changes in patients with cystic fibrosis using elexacaftor/tezacaftor/ivacaftor

Nocturnal oxygen therapy in obstructive sleep apnoea: a systematic review and meta-analysis.

Obstructive sleep apnoea is characterised by recurrent reduction of airflow during sleep leading to intermittent hypoxia. Continuous positive airway pressure is the first-line treatment but is limited by poor adherence. Nocturnal oxygen therapy may be an alternative treatment for obstructive sleep apnoea but its effects remain unclear. This meta-analysis evaluates the effects of nocturnal oxygen therapy on both obstructive sleep apnoea severity and blood pressure.A literature search was performed based on the Preferred Reporting Items for Systematic Review and Meta-analysis guidelines. Peer-reviewed, randomised studies that compared the effect of nocturnal oxygen therapy to sham in obstructive sleep apnoea patients were included. The main outcomes were the apnoea-hypopnoea index and systolic and diastolic blood pressure.The search strategy yielded 1295 citations. Nine studies with 502 participants were included. When nocturnal oxygen therapy was compared to sham/air, it significantly reduced the apnoea-hypopnoea index (mean difference (MD) -15.17 events·h-1, 95% CI -19.95- -10.38 events·h-1, p<0.00001). Nocturnal oxygen therapy had no significant effect on blood pressure at follow-up without adjustment for baseline values, but did, where available, significantly attenuate the change in blood pressure from baseline to follow-up for both systolic blood pressure (MD -2.79 mmHg, 95% CI -5.45- -0.14 mmHg, p=0.040) and diastolic blood pressure (MD -2.20 mmHg, 95% CI -3.83- -0.57 mmHg, p=0.008).Nocturnal oxygen therapy reduced the apnoea-hypopnoea index severity and the change in (but not absolute) systolic and diastolic blood pressure, compared to sham. This suggests that nocturnal oxygen therapy may be a treatment option for obstructive sleep apnoea. Further studies with longer-term follow-up and standardised measurements are needed.

Sleep disordered breathing in infants identified through newborn screening with spinal muscular atrophy

BackgroundSpinal muscular atrophy (SMA) is a genetic disorder that may result in neuromuscular weakness and respiratory insufficiency. Gene replacement therapy has changed the trajectory of this condition, but long-term outcomes related to sleep disordered breathing are not known. MethodsThis was a retrospective review of infants with SMA identified via newborn screening who subsequently received onasemnogene abeparvovec at the Hospital for Sick Children (Ontario, Canada). Polysomnograms were conducted at the time of confirmed diagnosis as well as regularly thereafter. ResultsEleven children (4 female) were identified via newborn screen (7 with 2 copies of the SMN2 gene and 4 with 3 copies of the SMN2 gene) and received onasemnogene abeparvovec at a median age of 3.6 weeks. All eleven infants met criteria for sleep disordered breathing based on their first completed polysomnograms but improved over time. Three infants required respiratory technology, including a premature infant who was prescribed nocturnal supplemental oxygen therapy for central sleep apnea and two symptomatic infants with neuromuscular weakness who required nocturnal noninvasive ventilation. We did not find a correlation between motor scores and polysomnogram parameters. ConclusionChildren treated with onasemnogene abeparvovec have reduced sleep disordered breathing over time. Polysomnograms revealed abnormal parameters in all children, but the clinical significance of these findings was unclear for children who were asymptomatic for sleep disordered breathing or neuromuscular weakness. These results highlight the need to evaluate both motor scores and respiratory symptoms to ensure a holistic evaluation of clinical status.

O017 Utility of Inpatient Overnight Oximetry

Abstract Background Overnight pulse oximetry is a non-invasive method of monitoring oxygen saturations. It has a myriad of clinical applications; including screening for moderate to severe sleep disordered breathing, identification and qualification of nocturnal hypoxia in patients who may benefit from domiciliary nocturnal oxygen and detection of nocturnal hypoventilation in patients with severe respiratory or neuromuscular disease. In our tertiary hospital, overnight oximetry is ordered at the discretion of sleep and respiratory physicians, without formal guidelines. Methods A retrospective review of patients who underwent inpatient overnight oximetry for any clinical indication in the period between January 2019 and December 2019 was performed. Electronic and paper-based medical records were reviewed and analysed. Subsequent in-laboratory polysomnography data and outpatient clinic review documentation was reviewed to determine the medium term impact of the oximetry. Progress to date 58 inpatient pulse oximetry studies were performed in the period examined. The indications for overnight oximetry fell into 4 groups - screening for sleep disordered breathing in patients with a high pre-test probability, assessment for domiciliary nocturnal home oxygen, assessment of adequacy of nocturnal oxygen therapy and assessment of adequacy of established positive airway pressure therapy. Intended Outcome and Impact There is no existing guidance on the use of overnight oximetry in adult inpatients. Our data shows that in patients with a high clinical suspicion of sleep disordered breathing, inpatient overnight oximetry frequently diagnosed sleep disordered breathing. In other patient groups, inpatient oximetry infrequently altered management. This data will help guide appropriate guidelines for inpatient overnight oximetry.

Nocturnal nasal high-flow oxygen therapy in elderly patients with concomitant chronic obstructive pulmonary disease and obstructive sleep apnea

PurposeThe coexistence of obstructive sleep apnea (OSA) and chronic obstructive pulmonary disease (COPD) is known as “overlap syndrome” (OS). Patients with OS are usually older than patients with OSA alone, suffer from more profound oxygen desaturation during the obstructive events often accompanied by sustained nocturnal hypoventilation. Although oxygen-enriched positive airway pressure (PAP) is the treatment of choice in these patients, this therapy is often poorly tolerated particularly by the elderly. The aim of this study was to assess the usefulness of nocturnal oxygen therapy via nasal high flow (NHF-OT) as a possible alternative to PAP in patients with OS.MethodsPatients > 65 years old with OS and nocturnal respiratory failure (time spent below SaO2 90% (T90) > 30%) had cardio-respiratory monitoring performed at baseline, during NHF-OT, or during conventional oxygen therapy (COT).ResultsA total of 40 patients were enrolled in the study. NHF-OT significantly reduced the apnea–hypopnea index (AHI) in all patients compared to baseline and COT. The mean basal AHI was 25.4 ± 8.6. During COT and NHF-OT, the AHI was 19.4 ± 7 and 5.4 ± 4.6, respectively (P < 0.001) and 19 patients reached an AHI < 5 during NHF-OT. The mean nocturnal SaO2% was 86.2 ± 2.6 at baseline and at equivalent FiO2 it significantly increased to 91.8 ± 2.4 during COT and to 93.9 ± 2.5 during NHF-OT (P < 0.001). The T90% was 48.7 ± 20.1 at baseline, 16.8 ± 11.7 during COT, and 8.8 ± 8.0 during NHF-OT (P < 0.001).ConclusionsIn elderly patients with OS, nocturnal treatment with NHF-OT significantly reduces obstructive episodes and improves oxygenation. As the treatment is generally well tolerated compared to PAP, NHF-OT may be a possible alternative therapy in this subgroup of patients.

Home oxygen for moderate hypoxaemia in chronic obstructive pulmonary disease: a systematic review and meta-analysis

Long-term oxygen therapy (LTOT) improves survival in patients with chronic obstructive pulmonary disease (COPD) and severe hypoxaemia. However, the best method of management of moderate hypoxaemia not qualifying for LTOT (including isolated nocturnal desaturation) is uncertain. We examined the effect of home oxygen (either LTOT or nocturnal oxygen therapy) on overall survival in patients with COPD and moderate hypoxaemia. In this systematic review and meta-analysis, we searched MEDLINE, Embase, the Cochrane Central Register of Controlled Trials, CINHAL, and Web of Science from database inception to Jan 13, 2022, for parallel-group randomised trials of long-term or nocturnal oxygen in patients with COPD and moderate daytime hypoxaemia or isolated nocturnal desaturation, or both. Control groups received usual care or ambient air through sham concentrators (placebo) throughout the study period. The primary outcome of interest was 3-year mortality. Crossover trials and trials of oxygen in severe hypoxaemia were excluded. Two reviewers applied inclusion and exclusion criteria to titles and abstracts and screened the full-text articles and reference lists of relevant studies. Aggregate data were extracted manually in duplicate using structured data collection forms. Methodological quality was assessed using the Cochrane Risk of Bias tool. Random-effects meta-analysis was used to pool individual studies. We considered the minimal clinically important difference for home oxygen to be a relative risk reduction in mortality at 3-year follow-up of 30-40%. The meta-analysis is registered on PROSPERO, CRD42021225372. We identified 2192 studies and screened 1447 after removal of duplicates, of which 161 were subjected to full-text screening, and six were identified as being eligible for inclusion. These six randomised trials were published between 1992 and 2020 and the quality of evidence was high. In the primary meta-analysis (five trials; 1002 patients), we found the effect of home oxygen in reducing 3-year mortality to be small or absent (relative risk 0·91 [95% CI 0·72-1·16]; τ² = 0·00), hence the lower limit of the 95% CI did not meet the prespecified minimal clinically important difference. The results of our meta-analysis suggest that home oxygen probably makes little or no difference to 3-year mortality in patients with COPD and moderate hypoxaemia. The data do not support the widespread use of home oxygen in this patient population. None.

Long-term oxygen therapy in COPD: what is the evidence?

Thomas L Petty was the founder of modern long-term oxygen therapy (LTOT).1 In 1967, Petty's group published the seminal study of six patients with severe chronic airway obstruction, in whom LTOT improved clinical status, exercise capacity, secondary erythrocythemia, and pulmonary hypertension.2 Notably, all patients had severe hypoxaemia (partial pressure of oxygen [PaO2] 41·5–46·5 mm Hg) and four patients were severely hypercapnic (partial pressure of carbon dioxide [PaCO2] 55·0–61·5 mm Hg). Thereafter, two randomised controlled trials that were initiated in the 1970s established a clear survival benefit related to LTOT in patients with chronic obstructive pulmonary disease (COPD) with severe resting hypoxaemia: the Nocturnal Oxygen Therapy Trial (NOTT)3 and the British Medical Research Council (BMRC) trial.

Management of Psychiatric Disorders in Patients with Respiratory Diseases.

Management of Psychiatric Disorders in Patients with Respiratory Diseases.

Effect of Nocturnal Oxygen on Blood Pressure Response to Altitude Exposure in COPD - Data from a Randomized Placebo-Controlled Cross-Over Trial.

PurposePatients with chronic obstructive pulmonary disease (COPD) are particularly vulnerable to hypoxia-induced autonomic dysregulation. Hypoxemia is marked during sleep. In COPD, altitude exposure is associated with an increase in blood pressure (BP) and a decrease in baroreflex-sensitivity (BRS). Whether nocturnal oxygen therapy (NOT) may mitigate these cardiovascular autonomic changes in COPD at altitude is unknown.Materials and MethodsIn a randomized placebo-controlled cross-over trial, 32 patients with moderate-to-severe COPD living <800 m were subsequently allocated to NOT and placebo during acute exposure to altitude. Measurements were done at low altitude at 490 m and during two stays at 2048 m on NOT (3 L/min) and placebo (3 L/min, ambient air) via nasal cannula. Allocation and intervention sequences were randomized. Outcomes of interest were BP, BRS (from beat-to-beat BP measurement), BP variability (BPV), and heart rate.ResultsAbout 23/32 patients finished the trial per protocol (mean (SD) age 66 (5) y, FEV1 62 (14) % predicted) and 9/32 experienced altitude-related illnesses (8 vs 1, p < 0.05 placebo vs NOT). NOT significantly mitigated the altitude-induced increase in systolic BP compared to placebo (Δ median −5.8 [95% CI −22.2 to −1.4] mmHg, p = 0.05) but not diastolic BP (−3.5 [95% CI −12.6 to 3.0] mmHg; p = 0.21) or BPV. BRS at altitude was significantly higher in NOT than in placebo (1.7 [95% CI 0.3 to 3.4] ms/mmHg, p = 0.02).ConclusionNOT may protect from hypoxia-induced autonomic dysregulation upon altitude exposure in COPD and thus protect from a relevant increase in BP and decrease in BRS. NOT may provide cardiovascular benefits in COPD during conditions of increased hypoxemia and may be considered in COPD travelling to altitude.

Effect of nocturnal oxygen therapy on exercise performance of COPD patients at 2048\xa0m: data from a randomized clinical trial

This 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}}}) at 490 m were: SpO2 92 ± 1%, CTO 65 ± 1%, {dot{text{V}}}_{{text{E}}} 37.7 ± 2.0 L/min; at 2048 m with placebo: SpO2 85 ± 1%, CTO 61 ± 1%, {dot{text{V}}}_{{text{E}}} 40.6 ± 2.0 L/min and with NOT: SpO2 84 ± 1%; CTO 61 ± 1%; {dot{text{V}}}_{{text{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.

Impact of nocturnal oxygen and CPAP on the ventilatory response to hypoxia in OSA patients free of overt cardiovascular disease

A primary characteristic of obstructive sleep apnea (OSA) is chronic exposure to intermittent hypoxia (IH) due to repeated upper airway obstruction. Chronic IH exposure is believed to increase OSA severity over time by enhancing the acute ventilatory response to hypoxia (AHVR), thus promoting ventilatory overshoot when apnea ends and perpetuation of apnea during sleep. Continuous positive airway pressure (CPAP), the gold-standard treatment of OSA, reduces the AHVR, believed to result from correction of IH. However, CPAP also corrects ancillary features of OSA such as intermittent hypercapnia, negative intrathoracic pressure and surges in sympathetic activity, which may also contribute to the reduction in AHVR. Therefore, the objective of this study was to investigate the impact of nocturnal oxygen therapy (to remove IH only) and CPAP (to correct IH and ancillary features of OSA) on AHVR in newly diagnosed OSA patients. Fifty-two OSA patients and twenty-two controls were recruited. The AHVR was assessed using a 5 min iscopanic-hypoxic challenge before, and after, treatment of OSA by nocturnal oxygen therapy and CPAP. Following baseline measurements, OSA patients were randomly assigned to nocturnal oxygen therapy (Oxygen, n = 26) or no treatment (Air; n = 26). The AHVR was re-assessed following two weeks of oxygen therapy or no treatment, after which all patients were treated with CPAP. The AHVR was quantified following ~4 weeks of adherent CPAP therapy (n = 40). Both nocturnal oxygen and CPAP treatments improved hypoxemia (p < 0.05), and, as expected, nocturnal oxygen therapy did not completely abolish respiratory events (i.e., apneas/hypopneas). Averaged across all OSA patients, nocturnal oxygen therapy did not change AHVR from baseline to post-oxygen therapy. Similarly, the AHVR was not altered pre- and post-CPAP (p > 0.05). However, there was a significant decrease in AHVR with both nocturnal oxygen therapy and CPAP in patients in the highest OSA severity quartile (p < 0.05). Nocturnal oxygen therapy and CPAP both reduce the AHVR in patients with the most severe OSA. Therefore, IH appears to be the primary mechanism producing ventilatory instability in patients with severe OSA via enhancement of the AHVR.

Effects of Altitude on Chronic Obstructive Pulmonary Disease Patients: Risks and Care.

Air travel and altitude stays have become increasingly frequent within the overall population but also in patients suffering from chronic obstructive pulmonary disease (COPD), which is the most common respiratory disease worldwide. While altitude is well tolerated by most individuals, COPD patients are exposed to some serious complications, that could be life-threatening. COPD patients present not only a respiratory illness but also frequent comorbidities. Beyond oxygen desaturation, it also affects respiratory mechanics, and those patients are at high risk to decompensate a cardiac condition, pulmonary hypertension, or a sleep disorder. Recently, there has been considerable progress in the management of this disease. Nocturnal oxygen therapy, inhaled medications, corticosteroids, inspiratory muscle training, and pulmonary rehabilitation are practical tools that must be developed in the comprehensive care of those patients so as to enable them to afford altitude stays.

Effect of Nocturnal Oxygen Therapy on Daytime Pulmonary Hemodynamics in Patients With Chronic Obstructive Pulmonary Disease Traveling to Altitude: A Randomized Controlled Trial.

IntroductionWe investigated whether nocturnal oxygen therapy (NOT) mitigates the increase of pulmonary artery pressure in patients during daytime with chronic obstructive pulmonary disease (COPD) traveling to altitude.MethodsPatients with COPD living below 800 m underwent examinations at 490 m and during two sojourns at 2,048 m (with a washout period of 2 weeks < 800 m between altitude sojourns). During nights at altitude, patients received either NOT (3 L/min) or placebo (ambient air 3 L/min) via nasal cannula according to a randomized crossover design. The main outcomes were the tricuspid regurgitation pressure gradient (TRPG) measured by echocardiography on the second day at altitude (under ambient air) and various other echocardiographic measures of the right and left heart function. Patients fulfilling predefined safety criteria were withdrawn from the study.ResultsTwenty-three COPD patients [70% Global Initiative for Chronic Obstructive Lung Disease (GOLD) II/30% GOLD III, mean ± SD age 66 ± 5 years, FEV1 54% ± 13% predicted] were included in the per-protocol analysis. TRPG significantly increased when patients traveled to altitude (from low altitude 21.7 ± 5.2 mmHg to 2,048 m placebo 27.4 ± 7.3 mmHg and 2,048 m NOT 27.8 ± 8.3 mmHg) difference between interventions (mean difference 0.4 mmHg, 95% CI −2.1 to 3.0, p = 0.736). The tricuspid annular plane systolic excursion was significantly higher after NOT vs. placebo [2.6 ± 0.6 vs. 2.3 ± 0.4 cm, mean difference (95% confidence interval) 0.3 (0.1 − 0.5) cm, p = 0.005]. During visits to 2,048 m until 24 h after descent, eight patients (26%) using placebo and one (4%) using NOT had to be withdrawn because of altitude-related adverse health effects (p < 0.001).ConclusionIn lowlanders with COPD remaining free of clinically relevant altitude-related adverse health effects, changes in daytime pulmonary hemodynamics during a stay at high altitude were trivial and not modified by NOT.Clinical Trial Registrationwww.ClinicalTrials.gov, identifier NCT02150590.

Central apnea and periodic breathing in children with underlying conditions.

SummaryCentral sleep apneas and periodic breathing are poorly described in childhood. The aim of the study was to describe the prevalence and characteristics of central sleep apnea and periodic breathing in children with associated medical conditions, and the therapeutic management. We retrospectively reviewed all poly(somno)graphies with a central apnea index ≥ 5 events per hr in children aged > 1 month performed in a paediatric sleep laboratory over a 6‐year period. Clinical data and follow‐up poly(somno)graphies were gathered. Ninety‐five out of 2,981 patients (3%) presented central sleep apnea: 40% were < 1 year, 41% aged 1–6 years, and 19% aged ≥ 6 years. Chiari malformation was the most common diagnosis (13%). Mean central apnea index was 20 ± 30 events per hr (range 5–177). Fifty‐eight (61%) children had an exclusive central pattern with < 5 obstructive events per hr. Periodic breathing was present in 79 (83%) patients, with a mean percentage of time with periodic breathing of 9 ± 16%. Among periodic breathing episodes, 40% appeared after a sigh, 8% after an obstructive event, 6% after breathing instability and 2% after bradypnea. The highest clinical apnea index and percentage of time with periodic breathing were observed in children with encephalopathy and/or epilepsy (68 ± 63 events per hr and 30 ± 34%). Clinical apnea index did not differ according to age, while periodic breathing duration was longer in children > 1 year old. Watchful waiting was performed in 22 (23%) patients with spontaneous improvement in 20. Other treatments (upper airway or neurosurgery, nocturnal oxygen therapy, continuous positive airway pressure, non‐invasive ventilation) were effective in selected patients. Central sleep apnea is rare in children and comprises heterogeneous conditions. Sleep studies are essential for the diagnosis, characterization and management of central sleep apnea.

Randomized Trial of Nocturnal Oxygen in Chronic Obstructive Pulmonary Disease

BackgroundLong-term oxygen therapy improves survival in patients with chronic obstructive pulmonary disease (COPD) and chronic severe daytime hypoxemia. However, the efficacy of oxygen therapy for the management of isolated nocturnal hypoxemia is uncertain.MethodsWe designed this double-blind, placebo-controlled, randomized trial to determine, in patients with COPD who have nocturnal arterial oxygen desaturation without qualifying for long-term oxygen therapy, whether nocturnal oxygen provided for a period of 3 to 4 years would decrease mortality or the worsening of disease such that patients meet current specifications for long-term oxygen therapy. Patients with an oxygen saturation of less than 90% for at least 30% of the recording time on nocturnal oximetry were assigned, in a 1:1 ratio, to receive either nocturnal oxygen or ambient air from a sham concentrator (placebo). The primary outcome was a composite of death from any cause or a requirement for long-term oxygen therapy as defined by the Nocturnal Oxygen Therapy Trial (NOTT) criteria in the intention-to-treat population.ResultsRecruitment was stopped prematurely because of recruitment and retention difficulties after 243 patients, of a projected 600, had undergone randomization at 28 centers. At 3 years of follow-up, 39.0% of the patients assigned to nocturnal oxygen (48 of 123) and 42.0% of those assigned to placebo (50 of 119) met the NOTT-defined criteria for long-term oxygen therapy or had died (difference, −3.0 percentage points; 95% confidence interval, −15.1 to 9.1).ConclusionsOur underpowered trial provides no indication that nocturnal oxygen has a positive or negative effect on survival or progression to long-term oxygen therapy in patients with COPD. (Funded by the Canadian Institutes of Health Research; INOX ClinicalTrials.gov number, NCT01044628.)

Long-term oxygen therapy in children with sickle cell disease and hypoxaemia

ObjectiveTo evaluate the acceptability and safety profile of nocturnal long-term oxygen therapy (LTOT) in children with sickle cell disease (SCD) and chronic hypoxaemia.DesignRetrospective cohort study.Patients, setting and interventionChildren with SCD...

Oxygen for interstitial lung diseases.

Supplemental oxygen therapy is prescribed for management of hypoxaemia in patients with interstitial lung disease (ILD). This review summarizes current evidence and implications of the use of supplemental oxygen therapy at home and during exercise training in ILD. Despite the significance of hypoxaemia in patients with ILD, there is a lack of high-quality evidence to guide the use of oxygen therapy in this population. Recent studies suggest that ambulatory oxygen may improve symptoms and health-related quality of life in patients with ILD. Long-term oxygen therapy for resting hypoxaemia in ILD is recommended by international guidelines. Supplemental oxygen during exercise may augment training effects, whereas therapeutic effects of nocturnal oxygen therapy are yet to be evaluated in patients with ILD. Nevertheless, it is important to consider the potential burden imposed by oxygen therapy on patients' daily activities of living. Ambulatory oxygen may be considered in ILD patients with exertional hypoxaemia, with long-term oxygen therapy being a standard care for resting hypoxaemia. Trials are currently underway to clarify therapeutic potentials of supplemental oxygen for exertional hypoxaemia and during exercise training in ILD patients, with additional research needed for the evaluation of nocturnal oxygen therapy.

Nocturnal oxygen therapy as an option for early COVID-19

There is currently no effective antiviral therapy or immune-based treatment for coronavirus disease (COVID-19). The urgent challenge is to prevent the transition of COVID-19 from mild to severe infection. This paper discussed nocturnal oxygen therapy as a new option for people with COVID-19 under home quarantine. It suggested that nocturnal oxygen therapy in the early stages may be helpful in preventing disease progression by inhibiting the rapid replication of the virus and improving the body's antiviral ability.

Effect of Nocturnal Oxygen Therapy on Nocturnal Hypoxemia and Sleep Apnea Among Patients With Chronic Obstructive Pulmonary Disease Traveling to 2048 Meters

There are no established measures to prevent nocturnal breathing disturbances and other altitude-related adverse health effects (ARAHEs) among lowlanders with chronic obstructive pulmonary disease (COPD) traveling to high altitude. To evaluate whether nocturnal oxygen therapy (NOT) prevents nocturnal hypoxemia and breathing disturbances during the first night of a stay at 2048 m and reduces the incidence of ARAHEs. This randomized, placebo-controlled crossover trial was performed from January to October 2014 with 32 patients with COPD living below 800 m with forced expiratory volume in the first second of expiration (FEV1) between 30% and 80% predicted, pulse oximetry of at least 92%, not requiring oxygen therapy, and without history of sleep apnea. Evaluations were performed at the University Hospital Zurich (490 m, baseline) and during 2 stays of 2 days and nights each in a Swiss Alpine hotel at 2048 m while NOT or placebo treatment was administered in a randomized order. Between altitude sojourns, patients spent at least 2 weeks below 800 m. Data analysis was performed from January 1, 2015, to December 31, 2018. During nights at 2048 m, NOT or placebo (room air) was administered at 3 L/min by nasal cannula. Coprimary outcomes were differences between NOT and placebo intervention in altitude-induced change in mean nocturnal oxygen saturation (SpO2) as measured by pulse oximetry and apnea-hypopnea index (AHI) measured by polysomnography during night 1 at 2048 m and analyzed according to the intention-to-treat principle. Further outcomes were the incidence of predefined ARAHE, other variables from polysomnography results and respiratory sleep studies in the 2 nights at 2048 m, clinical findings, and symptoms. Of the 32 patients included, 17 (53%) were women, with a mean (SD) age of 65.6 (5.6) years and a mean (SD) FEV1 of 53.1% (13.2%) predicted. At 490 m, mean (SD) SpO2 was 92% (2%) and mean (SD) AHI was 21.6/h (22.2/h). At 2048 m with placebo, mean (SD) SpO2 was 86% (3%) and mean (SD) AHI was 34.9/h (20.7/h) (P < .001 for both comparisons). Compared with placebo, NOT increased SpO2 by a mean of 9 percentage points (95% CI, 8-11 percentage points; P < .001), decreased AHI by 19.7/h (95% CI, 11.4/h-27.9/h; P < .001), and improved subjective sleep quality measured on a visual analog scale by 9 percentage points (95% CI, 0-17 percentage points; P = .04). During visits to 2048 m or within 24 hours after descent, 8 patients (26%) using placebo and 1 (4%) using NOT experienced ARAHEs (P < .001). Lowlanders with COPD experienced hypoxemia, sleep apnea, and impaired well-being when staying at 2048 m. Because NOT significantly mitigated these undesirable effects, patients with moderate to severe COPD may benefit from preventive NOT during high altitude travel. ClinicalTrials.gov Identifier: NCT02150590.

Reliability of Home Nocturnal Oximetry in the Diagnosis of Overlap Syndrome in COPD

Background: Chronic obstructive pulmonary disease (COPD) and sleep apnea are common conditions and often coexist. The proper diagnosis of sleep apnea may affect the management and outcome of patients with COPD. Objective: To determine the accuracy of home nocturnal oximetry to distinguish between nocturnal oxygen desaturation related to COPD alone or to sleep apnea in patients with moderate-to-severe COPD who have significant nocturnal hypoxemia with cyclical changes in saturation. Methods: This study involved a comparison of home nocturnal oximetry and laboratory-based polysomnography (PSG) in patients with moderate-to-severe COPD considered for inclusion in a trial of nocturnal oxygen therapy. All of the patients had significant nocturnal oxygen desaturation (defined as ≥30% of the recording time with a transcutaneous arterial oxygen saturation <90%) with cyclical changes in saturation suggestive of sleep apnea. Results: PSG was obtained in 90 patients; 45 patients (mean age = 68 years, SD = 8; 71% men; mean forced expiratory volume in 1 s [FEV₁] = 50.6% predicted value, SD = 18.6%; data from 41 patients) fulfilled the criteria for sleep apnea (mean apnea-hypopnea index = 32.6 events/h, SD = 19.9) and 45 patients (mean age = 69 years, SD = 8; 87% men; mean FEV₁ predicted value 44.6%, SD = 15%) did not (mean apnea-hypopnea index = 5.5 events/h, SD = 3.8). None of the patients’ characteristics (including demographic, anthropometric, and physiologic measures) predicted the diagnosis of sleep apnea according to PSG results. Conclusion: The diagnosis of sleep apnea in patients with moderate to severe COPD cannot rely on nocturnal oximetry alone, even when typical cyclical changes in saturation are seen on oximetry tracing. When suspecting an overlap syndrome, a full-night, in-laboratory PSG should be obtained.