Nocturnal Oxygen Research Articles

Individual heart failure patient variability in nocturnal hypoxia and arrhythmias.

Traditional heart failure research often uses daytime population parameter estimates to assess hypoxia and arrhythmias. This approach might not accurately represent heart failure patients as nighttime cardiac behaviors offer crucial insights into their health, especially regarding oxygen levels and heart rhythms. We conducted a prospective study on nocturnal oxygen saturation and heart rate in home-dwelling heart failure patients over 6 nights. Patients were recruited from the Walter Reed National Military Medical Center heart failure clinic. Criteria included a clinical diagnosis of heart failure, a New York Heart Association (NYHA) classification of I to III, ages between 21 to 90, cognitive intactness, capability to use the wearable device, and willingness to use the device for 6 consecutive nights. Average oxygen saturation was 92% with individual readings ranging from 40% to 100%. The mean heart rate was 72 beats per minute (bpm), but individual rates ranged from 18 bpm to a high of 296 bpm. A significant drop in oxygen levels and sleep arrhythmias were consistently observed among participants. Heart failure patients demonstrate notable and variable desaturations and arrhythmias across multiple nights. A single-night sleep study or a 24-hour heart rate monitor may not comprehensively depict patients' oxygenation and heart rate irregularities. Our research highlights wearable devices' potency in medical research for capturing essential nocturnal data. In only 6 nights, we gleaned invaluable clinical insights for optimizing patient care. This study is pioneering, being the first to intensively examine nighttime oxygen levels and heart rates in home-based heart failure patients.

Impact Of Nocturnal Oxygen Enrichment On High Elevation Acclimatization

Impact Of Nocturnal Oxygen Enrichment On High Elevation Acclimatization

Associations of polysomnographic measures of obstructive sleep apnea, and nocturnal oxygen saturation with incident type 2 diabetes mellitus in middle-aged and older men.

Obstructive sleep apnea (OSA) has been associated with incident type 2 diabetes mellitus (T2DM); however, few prospective epidemiological studies have accounted for important T2DM predictors including pre-diabetes status and testosterone. Participants in the longitudinal Men Androgens Inflammation Lifestyles Environment and Stress (MAILES) study, who underwent eight-channel home-based polysomnography (PSG) in 2010-2011 (n = 824) and were free of diabetes at baseline were included in the analysis (n = 682). From 2015 to 2021, 78.6% (n = 536) completed at least one follow-up assessment. Incident T2DM was determined by self-reported doctor diagnosis, diabetes medications, plasma glucose (fasting ≥7.0 mmol/L or random ≥11.0 mmol/L) or glycated haemoglobin ≥6.5%. Conservative hierarchical Poisson regression models adjusted associations of PSG metrics (categorical and continuous) for age, waist circumference, baseline fasting glucose and testosterone concentrations. In all, 52 men (9.7%) developed T2DM over a mean (range) of 8.3 (3.5-10.5) years. Significant age- and waist circumference-adjusted association of incident T2DM with rapid eye movement (REM) sleep apnea-hypopnea index (AHI) ≥20 events/h (incidence rate ratio [IRR] 1.5, 95% confidence interval [CI] 0.8-2.8; p = 0.23] and highest quartile of delta index (IRR 2.1, 95% CI 0.95-4.6; p = 0.066) were attenuated after adjustment for baseline glucose and testosterone, and the association with the lowest quartile of mean oxygen saturation persisted (IRR 4.2, 95% CI 1.7-10.3; p = 0.029). Categorical measures of AHI severity, oxygen desaturation index, and hypoxia burden index (HBI) were not independently associated with incident T2DM. Associations with T2DM were similar when continuous PSG variables were used; however, HBI was significant (IRR 1.015, 95% CI 1.006-1.024; p = 0.007). In a sub-sample with OSA treatment data (n = 479), these significant associations persisted after excluding adequately treated OSA (n = 32). Understanding underlying OSA endotypes generating hypoxaemia may identify opportunities for diabetes prevention.

Efficacy of pulmonary rehabilitation in patients with chronic obstructive pulmonary disease and obstructive sleep apnea; a randomized controlled trial.

To evaluate the efficacy of pulmonary rehabilitation in the outcomes of patients with chronic obstructive pulmonary disease-obstructive sleep apnoea overlap syndrome patients who used positive airway pressure. Prospective randomized controlled single- blind trial. A total of 79 patients with chronic obstructive pulmonary disease-obstructive sleep apnoea overlap syndrome were randomly assigned to either the intervention group (n = 40) or control group (n = 39). All patients consistently adhered to positive airway pressure therapy every night from enrolment in the study, while intervention group patients received additional moderate-intensity aerobic exercise for 20 weeks. Pre- and post-intervention measurements included the 6-Minute Walk Test, Barthel Index, body mass index, fat mass, free fat mass, forced expiratory volume in 1 s (FEV1), FEV1%predicted, modified Medical Research Council, and polysomnography parameters. After 20 weeks, the intervention group exhibited statistically significant improvements in 6MWD, Barthel Index, body mass index, fat mass, and modified Medical Research Council compared with control group (all p < 0.01). In addition, the intervention group showed a significantly lower percentage of total sleep time with oxygen saturation < 90% (p = 0.013) and higher lowest nocturnal oxygen saturation (p = 0.008) than the control group. However, there was no significant difference in FEV1 %predicted between the 2 groups. Pulmonary rehabilitation incorporating moderate-intensity aerobic exercise could improve physical endurance and motor abilities in individuals with chronic obstructive pulmonary disease-obstructive sleep apnoea overlap syndrome, while also improving anamnestic dyspnoea, body composition, and sleep-disordered breathing.

Novel advances in assessment and treatment of obstructive sleep apnea

The current indicators for assessing obstructive sleep apnea are sleep apnea-hypopnea index (AHI) and the lowest nocturnal oxygen saturation, but they do not comprehensively reflect the severity of the disease. The main treatments for OSA are continuous positive airway pressure, mandibular advancement devices and surgery, which have poor compliance and limited effectiveness. Therefore, there is a need to explore novel methods to assess and treat OSA. This article systematically summarized recent advances in this field.

Correlation between Heart Rate Variability and Disease Severity in Obstructive Sleep Apnea

Objective: This study aimed to investigate the variations in Heart Rate Variability (HRV) among individuals with Obstructive Sleep Apnea (OSA) and to explore the relationship between HRV, respiratory parameters, and disease severity. Methods: This prospective study included sixty participants diagnosed with OSA. Polysomnography (PSG) was utilized to assess HRV parameters, including time-domain and frequency-domain measures. Participants were categorized based on the severity of OSA, and data on hemoglobin (HGB), C-reactive protein (CRP), triglyceride (TG) levels, and nocturnal oxygen desaturation (NOD) were collected. Statistical analyses were performed to evaluate the correlations between HRV, respiratory parameters, and disease severity. Results: Among the participants, 23 (38%) had severe OSA, while 17 (28%) were habitual snorers (HS). Hemoglobin, C-reactive protein, and triglyceride levels were significantly higher in patients with severe OSA and NOD compared to HS individuals (p=0.002). Increased Epworth Sleepiness Scale (ESS) scores were associated with higher heart rates during sleep in severe OSA patients compared to HS individuals. NOD (+) patients exhibited statistically higher heart rates during sleep compared to NOD (-) patients (p=0.008). Individuals with an apnea/hypopnea index (AHI) &gt;30, NOD (+), and the lowest SpO2 percentage overnight had significantly lower HRV compared to HS and NOD (-) individuals. Conclusions: In addition to AHI, NOD and the lowest overnight SpO2 are significant markers of elevated cardiovascular risk and are useful for assessing HRV. These findings suggest that cardiovascular risks in OSA patients are heightened both during sleep and wakefulness. Therefore, individuals with severe symptoms, especially those with excessive daytime sleepiness, high levels of NOD, and low nocturnal SpO2 percentages, should be prioritized for treatment, alongside those with high levels of severe OSA.

Effects of Naltrexone on Sleep Quality and Periodic Breathing at High Altitude.

Foster, Katharine, James D. Anholm, Gary Foster, Suman Thapamagar, and Prajan Subedi. Effects of naltrexone on sleep quality and periodic breathing at high altitude. High Alt Med Biol. 00:000-000, 2024. Objective: This study examined the effects of naltrexone on breathing and sleep at high altitude. Mu-opioid receptor (MOR) agonists have a depressive effect on respiration. Naltrexone is known to block the MOR. We hypothesized that MOR blockade with naltrexone would result in higher nocturnal oxygen saturations, fewer apneas, and improved sleep at high altitude. Methods: This double-blind, placebo-controlled, crossover study included nine healthy volunteers (four females, five males) aged 27.9 (4.6) (mean [standard deviation]) years. Two overnight trips spaced at least 2 weeks apart took participants from Loma Linda, CA (355 m) to the Barcroft Laboratory, CA (3,810 m) for each arm. Participants ingested either 50 mg naltrexone or matching placebo at bedtime. Sleep metrics were recorded using an ambulatory physiological sleep monitor (APSM). Subjective data were measured with the Groningen Sleep Quality Scale, Stanford Sleepiness Scale, and the 2018 Lake Louise Score (LLS) for acute mountain sickness (AMS). Results: Mean overnight SpO2 was lower after taking naltrexone, 81% (6) versus 83% (4) (mean difference 1.9% [2.1, 95% confidence interval or CI = 0.1-3.6, p = 0.040]). The lowest overnight SpO2 (nadir) was lower on naltrexone 70% (6) versus 74% (4) (dif. 4.6% [4.3], CI = 1.0-8.2, p = 0.020). Total sleep time and total apnea-hypopnea index were unchanged. Subjective sleep quality was significantly worse on naltrexone measured via the Groningen Sleep Quality Scale (p = 0.033) and Stanford Sleepiness Scale (p = 0.038). AMS measured via LLS was significantly worse while taking naltrexone (p = 0.025). Conclusion: Contrary to our hypothesis, this study demonstrated a significant decrease in nocturnal oxygen saturation, worse sleep quality, and AMS scores. Further characterization of the MOR's effects on sleep and AMS is needed to evaluate potential exacerbating mechanisms for AMS and poor sleep quality at altitude.

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

Effects of acetazolamide on sleep disordered breathing in pulmonary vascular disease: a randomised controlled trial.

Patients with pulmonary vascular disease (PVD) often suffer from nocturnal hypoxaemia, but also from sleep apnoea. Short-term use of acetazolamide increases ventilation due to metabolic acidosis and also reduces loop gain. We investigated whether prolonged use of acetazolamide improves sleep disordered breathing in PVD. In a randomised controlled crossover trial, patients with PVD were randomly assigned to acetazolamide 250 mg and placebo twice daily for 5 weeks. Patients underwent respiratory polygraphy at baseline and at the end of each intervention phase. Outcomes of interest were the effect of acetazolamide on mean nocturnal oxygen saturation (S pO2 ), time with oxygen saturation <90% (t <90), apnoea-hypopnoea index (AHI) and sleep apnoea severity. In 20 patients with PVD (55% women, nine with pulmonary arterial hypertension, 11 with distal chronic thromboembolic pulmonary hypertension; mean±sd nocturnal S pO2 88.8±3.5%, obstructive AHI 12.6±12.3 events·h-1), 5 weeks of acetazolamide resulted in a significant improvement in nocturnal oxygenation compared to placebo (mean nocturnal S pO2 +2.3% (95% CI 1.3-3.3%); p<0.001 and t <90 -18.8% (95% CI -29.6- -8.0%); p=0.001). Acetazolamide increased the proportion of patients with mean nocturnal S pO2 ≥90% from 45% to 85%. The percentage of patients with AHI >5 events·h-1 was reduced from 75% to 60% and with AHI >15 events·h-1 from 30% to 15%. Two patients discontinued the study because of mild side-effects. Acetazolamide given for 5 weeks reduces nocturnal hypoxaemia in PVD to a clinically relevant level and reduces the proportion of patients with obstructive sleep apnoea.

Existence and pattern of sleep-related breathing disorders in patients diagnosed with bronchial asthma.

Asthma and obstructive sleep apnea (OSA) are commonly prevalent diseases, and both can co-exist to result in an alternate overlap syndrome, where a bidirectional relationship can adversely affect each other. This study aimed to determine the existence and pattern of sleep-related breathing disorders in subjects with bronchial asthma. It was prospectively conducted at the National Institute of Tuberculosis and Respiratory Diseases, New Delhi, in diagnosed cases of bronchial asthma. A subjective assessment of sleepiness was done using the Epworth sleepiness scale (ESS). All subjects underwent overnight polysomnography (PSG) in the Sleep Laboratory of the Institute. A total of 70 subjects were screened, and among them, finally, 30 were enrolled. The mean age of the subjects was 37.53±11.21 years, the mean body mass index (BMI) was 26.4±5.58 kg/m2, the mean ESS score was 3.1, and 80% of the subjects were male. After PSG, OSA (apnea hypopnea index >5/hour) was found in 63% (19/30) of the patients, of whom 43% had mild OSA, 10% had moderate OSA, and 10% had severe OSA. 10% (3/30) had nocturnal oxygen desaturation, while none had sleep hypoventilation. Patients with OSA compared to those without OSA had a higher BMI, more co-morbid allergic rhinitis, severe bronchial asthma, and a worse percentage of predicted forced expiratory volume in the first second. The study showed high detection rates of OSA in bronchial asthma patients. Hence, asthma patients should be evaluated for OSA.

Correlation between serum leptin level and sleep monitoring indexes in patients with obstructive sleep apnea hypopnea syndrome and its predictive value: a cross-sectional analysis.

To investigate the association between serum leptin (LP) level and polysomnography (PSG) parameters in patients with obstructive sleep apnea hypopnea syndrome (OSAHS). A cross-sectional study was conducted. The data of subjects who underwent PSG at hospital between January 2021 and December 2022 were collected retrospectively, 220 participants were included. The subjects were categorized into simple snoring group (n = 45), mild OSAHS group (n = 63), moderate OSAHS group (n = 52), and severe OSAHS group (n = 60). The general characteristics, PSG indices, and serological indices were collected retrospectively. Pearson correlation analysis was used to observe the correlation between serum LP level and PSG parameters. The value of serum LP level in predicting OSAHS was analyzed by receiver operating characteristic curve. The serum LP level was positively correlated with micro-arousal count, micro-arousal index (MAI), high apnea hypopnea index, times of blood oxygen decreased by≥3% and time in saturation lower 90%, and negatively correlated with lowest nocturnal oxygen saturation and mean oxygen saturation (p < 0.05). The area under the curve (AUC) of serum LP level in predicting the occurrence of OSAHS was 0.8276 (95% CI: 0.7713-0.8839), and when the Youden index was 0.587, the sensitivity was 72.00%, and the specificity was 86.67% (p < 0.0001). In the population with high MAI, the AUC of serum LP level in predicting the occurrence of OSAHS was 0.8825 (95% CI: 0.7833-0.9817), and when the Youden index was 0.690, the sensitivity was 79.00% and the specificity was 90.00% (p < 0.0001). Serum LP level is associated with the severity of OSAHS. Serum LP level demonstrates a strong predictive value for the occurrence of OSAHS, particularly in population with high MAI.

Burden of obstructive sleep apnea in patients with lung cancer and its effect on performance status.

The association between lung cancer and obstructive sleep apnea has remained a matter of debate for years. Obstructive sleep apnea is thought to increase the incidence of lung cancer due to intermittent hypoxaemia and sleep fragmentation. The aim of this study is to assess the prevalence of obstructive sleep apnea in patients with lung cancer and its effect on those patients' performance status. This is a prevalence study that was conducted at Chest Diseases Department, Alexandria Main University Hospitals. We enrolled 153 patients with lung cancer. All patients underwent cardiorespiratory monitoring using a home sleep-testing device. Performance status was assessed using Karnofsky performance status scale. The study included 120 (78.4%) males and 33 (21.6%) females newly diagnosed with lung cancer. The mean age was 59.98 ± 11.11 years. Obstructive sleep apnea (apnea-hypopnea index ≥ 5) was present in 134 (87.6%) patients. Eighty-five (63.4%) patients had mild obstructive sleep apnea, 39 (29.1%) patients had moderate obstructive sleep apnea, and 10 (7.46%) patients had severe obstructive sleep apnea. Prolonged nocturnal oxygen desaturation as demonstrated by time of oxygen saturation spent below 90% (T90%) during total sleep time > 30% was present in 25 (16.3%) patients. There was a significant difference in the median value of Karnofsky performance status scale between patients with lung cancer and associated obstructive sleep apnea and those without obstructive sleep apnea. In conclusion, obstructive sleep apnea is highly prevalent among patients with lung cancer. Performance status is worse among patients with lung cancer in the presence of obstructive sleep apnea. Screening patients with lung cancer for obstructive sleep apnea is important regardless of the presence of classical symptoms of obstructive sleep apnea.

Does obstructive sleep apnea–induced intermittent hypoxia increase the incidence of solitary pulmonary nodules, thyroid nodules, and other disorders? A retrospective study based on 750 cardiovascular disease patients

BackgroundObstructive sleep apnea (OSA) has been shown to be an important risk factor for cardiovascular disease (CVD), and intermittent hypoxia is an important pathogenetic factor for it. In the clinic, it was found that most CVD patients combined with OSA were also combined with solitary pulmonary nodules (SPN) or thyroid nodules (TN). Are these disorders related to intermittent hypoxia? One study showed that intermittent hypoxia is a pathogenic factor for lung cancer in mice, but there have been no clinical reports. So we conducted a retrospective study to explore whether intermittent hypoxia caused by OSA increases the incidence of SPN, TN, and other disorders.MethodsWe selected 750 patients with cardiovascular disease (CVD), who were divided into the control group and the OSA group according to the result of portable sleep monitoring. Retrospectively analyzed the comorbidities that patients with OSA are prone to and explored the correlation between OSA and those comorbidities.ResultsThe incidence of SPN, TN, cervical spondylosis, and carotid-artery plaques was higher in the OSA group than in the control group. These diseases are significantly associated with OSA (p < 0.05), and their incidence increased with an elevated apnea–hypopnea index. After excluding interference from age, gender, BMI, smoking history, history of lung disease, and history of tumors, OSA showed a significant correlation with SPN. After excluding age, gender, BMI, and thyroid disease, OSA was associated with TN. Patients with comorbidities have lower nocturnal oxygen saturation and more extended periods of apnea. Logistic multiple regression results revealed that male, advanced age, obesity, CS, and nasal septum deviation were independent risk factors for OSA.ConclusionsPatients combined with OSA may further develop more comorbidities, such as SPN, TN, and carotid-artery plaques. It may be related to intermittent hypoxia caused by OSA.

U-shaped relationship between lights-out time and nocturnal oxygen saturation during the first trimester: An analysis based on the nuMOM2b-SDB data

ObjectivePreventing adverse events due to unstable oxygen saturation (SpO2) at night in pregnant women is of utmost importance. Poor sleep has been demonstrated to impact SpO2 levels. Nowadays, many gravida have a habit of prolonged exposure to light before sleep, which can disrupt their sleep. Therefore, this study aimed at investigate the relationship between lights-out time, sleep parameters and SpO2, exploring the underlying mechanisms. MethodsThe data of 2881 eligible subjects from the Nulliparous Pregnancy Outcomes Study Monitoring Mothers-to-be and Sleep Disordered Breathing (nuMOM2b-SDB) database were analyzed. Multiple linear regression models were used to investigate the relationship between lights-out time and SpO2. In addition, restricted cubic splines (RCS) were employed to fit the nonlinear correlation between the two variables. The smoothing curve method was further utilized to depict the relationship between lights-out time and SpO2 based on various subgroup variables. ResultsAll participants were categorized according to race/ethnicity. A negative correlation was observed between nighttime lights-out time and average value of SpO2 (Avg-SpO2) (β = −0.05, p = 0.010). RCS revealed a U-shaped relationship between lights-out time and Avg-SpO2, with the turning point at 22:00. The subcomponent stratification results indicated that the Avg-SpO2 and minimum value of SpO2(Min-SpO2) of advanced maternal age decreased as the lights-out time was delayed. Furthermore, overweight and obese gravida showed lower Avg-SpO2 and Min-SpO2 levels than normal weight. ConclusionsA U-shaped relationship was identified between lights-out time and nocturnal Avg-SpO2 during early pregnancy, with the inflection at 22:00. Notably, later lights-out times are associated with lower levels of Min-SpO2 for advanced maternal age. The findings suggest that appropriately adjusting the duration of light exposure before sleep and maintaining a relatively restful state may be more beneficial for the stability of SpO2 in pregnant women. Conversely, deviations from these practices could potentially lead to pathological alterations in SpO2 levels.

Treatment of Sleep Apnea and Reduction in Blood Pressure: The Role of Heart Rate Response and Hypoxic Burden.

Obstructive sleep apnea is associated with increased blood pressure (BP). Obstructive sleep apnea treatment reduces BP with substantial variability, not explained by the apnea-hypopnea index, partly due to inadequate characterization of obstructive sleep apnea's physiological consequences, such as oxygen desaturation, cardiac autonomic response, and suboptimal treatment efficacy. We sought to examine whether a high baseline heart rate response (ΔHR), a marker of high cardiovascular risk in obstructive sleep apnea, predicts a larger reduction in post-treatment systolic BP (SBP). Furthermore, we aimed to assess the extent to which a reduction in SBP is explained by a treatment-related reduction in hypoxic burden (HB). ΔHR and HB were measured from pretreatment and posttreatment polygraphy, followed by a 24-hour BP assessment in 168 participants treated with continuous positive airway pressure or nocturnal supplemental oxygen from the HeartBEAT study (Heart Biomarker Evaluation in Apnea Treatment). Multiple linear regression models assessed whether high versus mid (reference) ΔHR predicted a larger reduction in SBP (primary outcome) and whether there was an association between treatment-related reductions in SBP and HB. A high versus mid ΔHR predicted improvement in SBP (adjusted estimate, 5.8 [95% CI, 1.0-10.5] mm Hg). Independently, a greater treatment-related reduction in HB was significantly associated with larger reductions in SBP (4.2 [95% CI, 0.9-7.5] mm Hg per 2 SD treatment-related reduction in HB). Participants with substantial versus minimal treatment-related reductions in HB had a 6.5 (95% CI, 2.5-10.4) mm Hg drop in SBP. A high ΔHR predicted a more favorable BP response to therapy. Furthermore, the magnitude of the reduction in BP was partly explained by a greater reduction in HB.

Screening and early warning system for chronic obstructive pulmonary disease with obstructive sleep apnoea based on the medical Internet of Things in three levels of healthcare: protocol for a prospective, multicentre, observational cohort study

IntroductionChronic obstructive pulmonary disease (COPD) and obstructive sleep apnoea (OSA) are prevalent respiratory diseases in China and impose significant burdens on the healthcare system. Moreover, the co-occurrence of COPD and...

Effects of 5-Week Oral Acetazolamide on Incremental Cycling Exercise in Pulmonary Arterial and Chronic Thromboembolic Pulmonary Hypertension: A Randomized Placebo-Controlled, Double-Blinded, Crossover Trial

Introduction: Acetazolamide (AZA) improves nocturnal and daytime blood oxygenation in patients with pulmonary vascular disease (PVD), defined as pulmonary arterial and distal chronic thromboembolic pulmonary hypertension (CTEPH), and may improve exercise performance. Methods: We investigated the effect of 5 weeks of AZA (250 mg bid) versus placebo on maximal load during incremental cycling ramp exercise in patients with PVD studied in a randomized controlled, double-blind, crossover design, separated by > 2 weeks of washout. Results: Twenty-five patients (12 pulmonary arterial hypertension, 13 CTEPH, 40% women, age 62 ± 15 years) completed the trial according to the protocol. Maximum load was similar after 5 weeks of AZA versus placebo (113 ± 9 vs. 117 ± 9 watts [W]), mean difference −4 W (95% CI: −9 to 1, p = 0.138). With AZA, maximum (max)-exercise partial pressure of O₂ (PaO₂) was significantly higher by 1.1 kPa (95% CI: 0.5–1.8, p = 0.003), while arterial pH and partial pressure of CO₂ were significantly lower. Gas exchange threshold was reached at a higher load with AZA (108 ± 8 W vs. 97 ± 8 W) and was therefore delayed by 11 W (95% CI: 3–19, p = 0.013), while the ventilatory equivalent for O₂ and CO₂ were significantly higher at both the max-exercise and gas exchange threshold with AZA versus placebo. Conclusion: AZA for 5 weeks did not significantly change maximum exercise capacity in patients with PVD despite a significant increase in PaO₂. The beneficial effects of increased blood oxygenation may have been diminished by increased ventilation due to AZA-induced metabolic acidosis and increased dyspnea.

Survival of Infants With Severe Congenital Kidney Disease After ECMO and Kidney Support Therapy.

Congenital kidney failure not only affects the homeostatic functions of the kidney, but also affects neonatal respiratory integrity. Until recently, extracorporeal membrane oxygenation (ECMO) support was not used in this population because the need for ECMO clearly established nonviability. Since 2016, 31 neonates have been admitted to the NICU at Children's of Alabama with congenital kidney failure. Five patients were placed on ECMO for severe respiratory distress unresponsive to conventional interventions. We evaluated neonates with congenital kidney failure and pulmonary hypoplasia/hypertension refractory to conventional therapies who received ECMO support within the first 9 postnatal days. We describe the pre and postnatal diagnoses, ECMO course details, dialysis modalities, complications, procedures, and long-term outcomes of these patients. All 5 patients received kidney support therapy by postnatal day 7. Diagnoses included posterior urethral valves, bilateral renal dysplasia, and autosomal recessive polycystic kidney disease. Gestational age ranged from 35.6 to 37.1 weeks. Birth weight ranged from 2740 to 3140 g. Days on ECMO ranged from 4 to 23. Four survived and are living today. Pulmonary hypertension resolved in surviving patients. Three surviving patients require no oxygen support, and 1 patient requires nocturnal oxygen. Three survivors received a kidney transplant, and 1 awaits transplant evaluation. Patients with congenital kidney failure with severe pulmonary hypoplasia/pulmonary hypertension no longer warrant a reflexive assignment of nonviability. Meticulous ECMO, respiratory, nutritional, and kidney support therapies may achieve a favorable long-term outcome. Further investigation of strategies for optimal outcome is needed.

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.

Expedition 5300: limits of human adaptations in the highest city in the world.

Exposure to chronic hypobaric hypoxia imposes a significant physiological burden to more than 80 million humans living above 2500m throughout the world. Among them, 50000 live in the world's highest city, La Rinconada, located at 5000-5300m in southern Peru. Expedition 5300 is the first scientific and medical programme led in La Rinconada to investigate the physiological adaptations and altitude-related health issues in this unique population. Dwellers from La Rinconada have very high haemoglobin concentration (20.3±2.4g/dL; n=57) and those with chronic mountain sickness (CMS) exhibit even higher concentrations (23.1±1.7g/dL; n=150). These values are associated with large total haemoglobin mass and blood volume, without an associated iron deficit. These changes in intravascular volumes lead to a substantial increase in blood viscosity, which is even larger in CMS patients. Despite these large haematological changes, 24h blood pressure monitoring is essentially normal in La Rinconada, but some results suggest impaired vascular reactivity. Echocardiography revealed large right heart dilatation and high pulmonary arterial pressure as well as left ventricle concentric remodelling and grade I diastolic dysfunction. These changes in heart dimension and function tend to be more severe in highlanders with CMS. Polygraphy evaluations revealed a large reduction in nocturnal pulse oxygen saturation (median SpO2 =79%), which is even more severe in CMS patients who also tended to show a higher oxygen desaturation index. The population of La Rinconada offers a unique opportunity to investigate the human responses to chronic severe hypoxia, at an altitude that is probably close to the maximum altitude human beings can permanently tolerate without presenting major health issues.