Nocturnal Oxygen Desaturation Research Articles

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.

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.

No Difference in Sleep Desaturations Severity between Patients with Wake-Up and Non-Wake-Up Stroke: A PRESS Study Results

Wake-up stroke (WUS) is a certain type of ischemic stroke in which a patient wakes up with a new neurological deficit due to cerebral ischemia. Sleep-disordered breathing is an independent risk factor for stroke, but the role of nocturnal oxygen desaturation in the pathophysiology of WUS is still insufficiently explored. According to several studies, patients with WUS have a significantly more severe sleep apnea syndrome and lower mean blood oxygen saturation. This study aimed to assess the severity of nocturnal desaturations in acute WUS and non-WUS patients using nocturnal pulse oximetry. The cohort of 225 consecutive patients with neuroimaging-verified acute cerebral ischemia was prospectively enrolled. For further analyses, 213 subjects with known WUS/non-WUS status were selected (111 males and 102 females, average age 70.4 ±12.9, median baseline NIHSS = 5, median baseline mRS = 3). Patients were divided into the WUS group (n = 45) and the non-WUS group (n = 168). Overnight pulse oximetry was performed within 7 days of the stroke onset and data of both of the studied groups were compared. We found oxygen desaturation index (ODI) in the WUS group was 14.5 vs. 16.6 (p = 0.728) in the non-WUS group, basal O2 saturation was 92.2% vs. 92.5% (p = 0.475), average low O2 saturation was 90.3% vs. 89.6% (p = 0.375), minimal O2 saturation was 79.5% vs. 80.6% (p = 0.563), and time with O2 saturation <90% (T90) was 4.4% vs. 4.7% (p = 0.729). In the studied sample, monitored respiratory parameters including ODI, basal O2 saturation, average low O2 saturation, minimal O2 saturation, and T90 did not significantly differ between groups of WUS and non-WUS patients.

PREVALENCE OF OVERLAP SYNDROME AND ITS CORRELATION WITH VARIOUS COMORBIDITIES IN COPD PATIENTS ADMITTED IN A TERTIARY CARE HOSPITAL: A COHORT STUDY

Introduction:Theoverlapsyndromewas first coinedbyDavidC.Flenley in1985 todescribethecoexistenceofobstructive sleep apnoea (OSA) in patients with chronic obstructive pulmonary disease (COPD). Patients with Overlap Syndrome experience more profound nocturnal oxygen desaturation (NOD) than patients with OSA or COPD alone. Little is known about the possible predictors of the overlap syndrome and its association with comorbidities contributing to impaired outcome.Objectives:This study aimed to evaluate the prevalence and possible predictors of the overlap syndrome and its correlation with various comorbidities in a cohort of COPD patients.Materials &amp; Methods:Individuals with COPD (GOLD, riskgroupsA–D) admittedinourhospitalfromMarch2021 toDecember 2021.Informationonage,gender,bodymass index (BMI), waist-hip ratio, smoking status, Adjusted neck circumference Epworth sleepiness scale (ESS),STOP BANG, COPD assessment test score,comorbidities,was collectedanda spirometry wasperformed.Participants underwent Level 1 sleep study in our hospital.An apnoea-hypopnea index (AHI) &gt;5 per hour was considered to indicate OSA. Results:Around 50 patients were enrolled with a mean age of 60.7 of whom male is 52 % and female is 48%. During nocturnal polysomnography, 39.1% had evidence of OSA.AHI had statisticaly correlated with Diabetes,Hypertension (p value&lt;0.005).Also in our study we found AHI had statisticaly correlated between ESS score and severity of COPD (GOLD Class B &amp; C)(p value&lt;0.005).Pulmonary Arterial Hypertension and Diabetes were more common in patients with overlap syndrome. Conclusion: The prevalence of COPD patients with OSA is 24%. BMI and smoking history seems to be a predictoroftheoverlapsyndrome.Thesepatientsmaybemoreaffectedbypulmonaryarterialhypertensionanddiabetes

Obstructive sleep apnea and pulmonary hypertension: the pendulum swings again.

Obstructive sleep apnea and pulmonary hypertension: the pendulum swings again.

Study of Nocturnal Oxygen Desaturation in Chronic Obstructive Pulmonary Disease Patients

Background: Abnormal sleep architecture with decreased rapid eye movement sleep and arousals during the periods of nocturnal oxygen desaturation (NOD) are seen in patients with chronic obstructive pulmonary disease (COPD) with significant consequences. This study was done to evaluate the prevalence of NOD and other sleep-related disorders in COPD patients. Patients and Methods: This prospective cross-sectional study was conducted in the sleep laboratory of our tertiary center over 1 year. Fifty COPD patients were enrolled in this study. They were classified into mild COPD and moderate COPD, according to the Global Initiative for Obstructive Lung Disease (GOLD) classification. Complete history, physical examination, and relevant laboratory investigations were taken. All patients were subjected to overnight polysomnography. Results: Eight patients had mild COPD, whereas 42 patients had moderate COPD. Mean sleep efficiency was decreased with an average of 71.08% with a significant difference between mild and moderate COPD cases. Minimal SpO2, average SpO2, SpO2

Alternative Sleep Apnea Treatment: Reply.

We thank Roy et al.1 for their relevant comments on our article.2 As Roy et al. correctly pointed out, head-of-bed elevation by 30 degrees did not significantly improve oxygenation variables such as mean nadir oxygen saturation measured by pulse oximetry (Spo2), lowest Spo2, and percent time Spo2 &lt; 90% in our study although, Souza’s previous study demonstrated improvement of both apnea hypopnea index (15.7 to 10.7 events/h) and lowest Spo2 (83.5 to 87%) in symptomatic obstructive sleep apnea (OSA) patients with only 7.5-degree head-of-bed elevation.3 It would be easy to comment that different patient populations and study design are the cause of the difference. However, we consider that Roy’s question has an important pathophysiologic background calling the readers’ attention. First, Souza’s patients are more obese than ours (body mass index: 29.6 ± 4.8 vs. 26.3 ± 4.5 kg/m2), and, therefore, head-of-bed elevation is expected to increase functional residual capacity and improve oxygenation more effectively in such obese patients. Furthermore, head-of-bed elevation improves pharyngeal airway collapsibility as many previous studies have reported. Our research group demonstrated approximately 6 cm H2O improvement of pharyngeal closing pressure by 60-degree sitting position in anesthetized and paralyzed patients with OSA.4 Notably, the improvement of pharyngeal closing pressure was indirectly associated with the severity of OSA. Accordingly, apnea hypopnea index is expected to decrease more effectively in Souza’s patients with less severe OSA (15.7 vs. 59.6 events/h), and, in fact, application of only 7.5-degree head-of-bed elevation did achieve successful improvement. Considering both Souza’s and our findings, head-of-bed elevation does provide better nocturnal oxygenation and breathing pattern, but the optimal degree of head-of-bed elevation may depend on the severity of obesity and OSA.Second, Roy et al. raised optimal oxygen therapy for patients with the overlap syndrome, in which two diseases, chronic obstructive pulmonary disease and OSA, coexist in a single patient. In our study, four participants had both diseases. Two of them did not improve apnea hypopnea index with the combination therapy of head-of-bed elevation and high-flow nasal cannula with 40% oxygen concentration. Currently, the overlap syndrome receives special attention in the fields of pulmonology and sleep medicine because of its greater degrees of nocturnal oxygen desaturation and cardiovascular consequences than those with either condition in isolation.5 Although this is not the original scope of our study, the overlap syndrome also needs to be paid more attention by anesthesiologists because of the possible development of severe sustained and episodic hypoxemia after surgery, leading to poor postoperative outcome. To date, we do not know whether continuous or bilevel positive airway pressure therapy is effective and what level of oxygen concentration is appropriate for postoperative respiratory management in patients with the overlap syndrome. Optimal continuous positive pressure for OSA may negate the auto–positive end-expiratory pressure in the overlap syndrome patients with emphysema phenotype. In contrast, bilevel positive pressure ventilation may be advantageous in emphysema-predominant patients because continuous positive pressure may exacerbate mechanical disadvantage of the flattened diaphragm contraction leading to severe hypoventilation during sleep. We would like to close our comments by sharing the most recent clinical study demonstrating the effectiveness of high-flow nasal oxygen therapy (30 to 60 l/min with oxygen concentration titrated to increase awake Spo2 by 3 to 4%) for treatment of the overlap syndrome.6 Yes, all issues raised by Roy et al. are clinically relevant and to be fully answered in the near future.The authors declare no competing interests.

Effect of CPAP therapy on blood pressure in patients with OSA: a worldwide individual patient data meta-analysis

Abstract Background Obstructive sleep apnoea (OSA) is a well-known cardiovascular risk factor and is frequently associated with hypertension. The treatment of OSA with continuous positive airway pressure (CPAP) can resolve apnoeas, hypoxia, and sympathetic hyperactivation. Meta-analyses of randomised controlled trials (RCTs) show that CPAP treatment modestly reduces blood pressure (BP) with a pronounced heterogeneity among different OSA patient subgroups. Purpose To study the effects of CPAP treatment on BP changes, and to identify predictors of BP response to CPAP through analysis of individual patient data from published RCTs. Methods Study groups who had published RCTs on the effect of CPAP therapy on BP in OSA were invited to share the individual patient data (i.e. BP values, history of hypertension and antihypertensive drugs use). The outcomes of interest were the group-difference (BP at follow-up – BP at baseline) in office and out-of-office BP. Data analysis was performed with a one-step approach using a linear regression model, with treatment as covariate, including a random effect. An additional analysis was performed by stratifying patients in three subgroups: normotension, controlled hypertension and uncontrolled hypertension, based on BP at baseline, history of hypertension or treatment with antihypertensive drugs. Lastly, we evaluated the determinants of CPAP associated BP changes. Results Individual patient data from 34 parallel-group RCTs (n=7,456, 72% males, body mass index, BMI 31.9±14.8 kg/m2, age 58.6±10.9 years, apnoea-hypopnoea index, AHI 35.5±20.6 /hour) were analysed. The overall CPAP effect was larger for 24-BP compared to office BP measurements (Table 1), the highest reductions being observed for nocturnal BP. The stratified analysis showed a consistent BP lowering effect in the group of patients with uncontrolled hypertension whereas there was no significant BP change in those with controlled hypertension or in normotensives (figure 1). Higher BP levels at baseline and history of hypertension were independent predictors of BP reduction by CPAP for office and 24-BP measurements. Younger age and more severe nocturnal oxygen desaturations predicted a larger treatment effect on office BP only. Conclusions BP response to CPAP in OSA patients varies in different patient groups as a function of baseline BP, the greatest reduction being observed in younger patients with uncontrolled BP. Thus, our individual patient data meta-analysis indicates that younger patients with uncontrolled hypertension and more severe nocturnal oxygen desaturations measured by minimum SpO2 are likely to benefit the most from CPAP treatment in terms of BP reduction. Funding Acknowledgement Type of funding sources: None.

Association between nocturnal oxygen desaturation and ischaemic stroke outcomes.

This study aimed to assess the association between nocturnal hypoxemia and early acute ischaemic stroke (AIS) outcomes in patients without oxygen supplementation. One hundred and six AIS patients consecutively admitted to the stroke unit were included in this study. Baseline demographic and medical data and arterial blood saturation (SpO2) measurements during night-sleep (from 10pm to 6am) were examined for their association with stroke outcomes, including the National Institutes of Health Stroke Scale (NIHSS) score on the 7th day or differences between the NIHSS score on the 1st day and the 7th day after stroke onset. Measurements of SpO2 were made using a pulse oximeter of the Spacelabs Medical Inc. (USA) monitoring system, and the number of apnoea episodes and their duration were recorded by ECG Holter with respiration monitoring (CardioMem®, Getamed, GE). The study showed that age (Spearman's r = 0.207, p = 0.033) and parameters attributable to anaemia (RBC r = -0.205, p = 0.035, Hb r = -0.225, p = 0.02 and HCT r = -0.196, p = 0.044), atrial fibrillation and ischaemic changes in both brain hemispheres (p = 0.023 and 0.01, respectively) were correlated with the study outcomes. In terms of saturation parameters, we demonstrated that the 'total desaturation burden' (i.e. [100% minus actual measured SpO2%] x apnoea duration) and multiple apnoeas of longer than 20 seconds were correlated with worse functional outcomes. Measures of shorter desaturation episodes (i.e. SpO2 oxygen desaturation index (ODI) at 3% and 4%, and time-weighted desaturations below the determined thresholds (SpO2 from 95% to 85%) demonstrated non-significant associations with the study outcomes. This study demonstrated that long-lasting desaturation episodes during the night, depicted by the 'total desaturation burden', were correlated with worse functional outcomes in AIS, while measures of shorter desaturation episodes were not correlated. In future clinical trials, indications for oxygen supplementation should include the methodology of personalised medicine and introduce individual approaches based on specially formulated, novel multifactorial algorithms.

Severity of oxygen desaturation in OSA–COPD overlap syndrome compared to OSA alone: an observational cohort study

Abstract Chronic obstructive pulmonary disease (COPD) and obstructive sleep apnoea (OSA) syndrome (OSAS) are both common conditions. Their comorbid association – overlap syndrome (OVS) – can result in clinically important nocturnal oxygen desaturation. We sought to compare demographic and anthropometric characteristics, associated comorbidities and oxygen saturation in patients with OVS versus OSA alone. Methods We included consecutive patients diagnosed with OSA in our sleep laboratory. Overnight sleep studies were performed, and data regarding demographic and anthropometric characteristics, prevalence of comorbidities and somnographic parameters were compared for patients with OVS versus OSA alone. A P value of &lt;0.05 was considered significant. Results A total of 2173 OSA patients were assessed, of whom 381 (17.5%) had OVS. Significant differences were found between the OVS and OSA groups regarding all evaluated demographic and anthropometric characteristics, prevalence of comorbidities and somnographic parameters. Conclusions OVS patients were older, were predominantly male, had a higher prevalence of common cardiovascular and metabolic comorbidities, and had worse apnoea–hypopnoea index (AHI) and oxygen saturation parameters.

Sleep-Disordered Breathing in Newly Diagnosed Patients of Lung Cancer.

Sleep-disordered breathing (SDB) is highly prevalent in patients with cancer and affects their prognosis. However, data on SDB in lung cancer patients are lacking, and few studies have conducted level I polysomnography (PSG) in this patient population. This study aimed to measure SDB in newly diagnosed lung cancer patients at the sleep clinic of a tertiary respiratory institute in New Delhi, India, for eight months. This study included 30 patients. Participants received a clinical examination, completed a sleep questionnaire, and then underwent overnight PSG. We scored sleep parameters according to the American Academy of Sleep Medicine guidelines. Both descriptive and inferential statistics were used to analyze the data. We used univariate analysis with chi-square testing, and p<0.05 was considered significant. SDB and obstructive sleep apnea (OSA) were found in 66.6% and 56.6% of patients, respectively. Mild, moderate, and severe OSA were seen in 26.6%, 16.6%, and 13.3% of patients, respectively. Nocturnal oxygen desaturation (NOD) or NOD90 (i.e., when >30% of sleep time was spent with oxygen saturation levels <90%) was seen in 13.3% of patients. Adenocarcinoma was the most common histological variant of cancer. Tumor-node-metastasis staging was significantly associated with the presence of OSA (p=0.045). Lung cancer patients should receive routine PSG to identify and manage patients with SDB, especially given that symptoms of SDB such as easy fatigability and non-refreshing sleep are overlooked as symptoms of lung cancer. Proper management of SDB or OSA would help improve patients' quality of life and improve their overall prognosis.

Nocturnal Oxygen Desaturation Index Correlates with Respiratory Depression in Post-Surgical Patients Receiving Opioids - A Post-Hoc Analysis from the Prediction of Opioid-Induced Respiratory Depression in Patients Monitored by Capnography (PRODIGY) Study.

PurposePostoperative monitoring of respiratory status on general care wards typically consists of intermittent checks of oxyhemoglobin saturation and respiratory rate, allowing substantial unmonitored time for severe opioid induced respiratory depression (RD) to develop unnoticed. Oxygen desaturation index (ODI) can be computed solely by continuous pulse oximetry monitoring. In this post-hoc analysis, we evaluate whether nocturnal ODI correlates with RD.Patients and MethodsThe PRODIGY trial (NCT02811302) was a multinational study conducted where adult patients receiving parenteral opioids on the general care floor were continuously monitored by blinded pulse oximetry and capnography monitoring to detect episodes of RD. An RD episode was defined as: respiratory rate ≤5 breaths/min (bpm) for ≥3 minutes, oxygen saturation (SpO2) ≤85% for ≥3 minutes, end-tidal carbon dioxide (EtCO2) ≤15 or ≥60 mm Hg for ≥3 minutes, apnea episode lasting >30 seconds, or any respiratory opioid-related adverse event. Data were used to calculate nocturnal (00:00 ─ 06:00) ODI4% based on desaturation episodes (4% decrease from mean oxyhemoglobin saturation in the past 120 seconds, lasting ≥10 seconds). Continuous monitoring began after a patient received parenteral opioids, allowing identification of potential RD and ODI4% episodes during opioid therapy. The average number of ODI4% episodes (≥1, ≥5, ≥10, ≥15 episodes/hour) were analyzed. Logistic regression and area under the receiver operating characteristic curve (AUC) were computed.ResultsA final cohort of 1072 (out of 1335) patients had sufficient data, with 76% (N=817/1072) having ≥1 episode of ODI4%. Multivariable logistic regression showed that ODI4% was strongly associated with RD, with greater risk for higher ODI4% scores: ≥5 episodes/hour odds ratio 2.59 (95% CI 1.72–3.89, p<0.0001); ≥10 episodes/hour 3.39 (95% CI 1.80–6.39, p=0.0002); ≥15 episodes/hour 4.71 (95% CI 1.93–11.47, p=0.0006).There was no significant association between ODI4% and respiratory adverse events.ConclusionNocturnal ODI4% was highly correlated with RD among hospitalized patients receiving parenteral opioids. Patients with a high ODI4%, especially with ≥15 episodes/hour, are more likely to experience RD and should be evaluated for the need of closer monitoring after opioid administration.

Obstructive Sleep Apnea and Hypertension: Updates to a Critical Relationship.

Purpose of ReviewObstructive sleep apnea (OSA) is an underdiagnosed illness linked to essential hypertension (HTN), resistant hypertension (r-HTN), and cardiovascular disease (CVD). This review provides updates on the epidemiology, pathophysiology, and treatments of OSA-associated HTN.Recent FindingsMild sleep apnea increases the risk for HTN. Eighty-nine percent of young patients aged 18–35 with HTN not attributed to secondary causes have underlying OSA. Home sleep studies are noninferior to formal polysomnography for OSA diagnosis. Nocturnal oxygen desaturation rate is positively correlated with HTN severity. Gut microbiome neo-colonization in response to high-fat diet cravings in patients with OSA alters immune function and worsens HTN. Carbonic anhydrase inhibitors and probiotics show newfound potential for OSA-associated HTN treatment. OSA recognition improves hospital outcomes after a STEMI. Hypoxia-inducible factor (HIF) transcription increases in a dose-dependent manner to hypoxia, and HIFs are strongly linked to cancer growth.SummaryOSA and HTN are comorbid conditions with adversely connected pathophysiology including sympathetic hyperactivity, gut dysbiosis, proinflammation, endothelial damage, rostral fluid shifts, pharyngeal collapse, intravascular fluid retention, nocturnal energy expenditure, and metabolic derangements. The dose–response effect of OSA on HTN severity challenges blood pressure (BP) control, so those with refractory HTN should be screened for OSA.

Sleep-Related Breathing Complaints in Chronic Obstructive Pulmonary Disease.

This review presents the normal physiologic changes in ventilation during sleep and how they can be detrimental to chronic obstructive pulmonary disease (COPD). Sleep-related breathing disorders (SRBDs) in COPD lead to higher morbidity and mortality if left unrecognized and untreated. The diagnosis of SRBDs requires a high index of suspicion, as symptoms may overlap with other sleep disorders. Mortality risk is improved when patients with COPD with OSA (overlap syndrome) are treated with positive airway pressure and when long-term nocturnal noninvasive ventilation is started on chronic stable hypercapnic COPD. Treatment of isolated nocturnal oxygen desaturation has not been associated with improved survival.

Association and Risk Factors for Obstructive Sleep Apnea and Cardiovascular Diseases: A Systematic Review

Obstructive sleep apnea (OSA) is a serious, potentially life-threatening condition. Epidemiologic studies show that sleep apnea increases cardiovascular diseases risk factors including hypertension, obesity, and diabetes mellitus. OSA is also responsible for serious illnesses such as congestive heart failure, stroke, arrhythmias, and bronchial asthma. The aim of this systematic review is to evaluate evidence for the association between OSA and cardiovascular disease morbidities and identify risk factors for the conditions. In a review of 34 studies conducted in 28 countries with a sample of 37,599 people, several comorbidities were identified in patients with severe OSA—these were: heart disease, stroke, kidney disease, asthma, COPD, acute heart failure, chronic heart failure, hyperlipidemia, thyroid disease, cerebral infarct or embolism, myocardial infarction, and psychological comorbidities including stress and depression. Important risk factors contributing to OSA included: age > 35 years; BMI ≥ 25 kg/m2; alcoholism; higher Epworth sleepiness scale (ESS); mean apnea duration; oxygen desaturation index (ODI); and nocturnal oxygen desaturation (NOD). Severe OSA (AHI ≥ 30) was significantly associated with excessive daytime sleepiness and oxygen desaturation index. The risk of OSA and associated disease morbidities can be reduced by controlling overweight/obesity, alcoholism, smoking, hypertension, diabetes mellitus, and hyperlipidemia.

Average Lifetime Hemoglobin Concentration Improves Prediction of Cognitive Outcomes in Pediatric Patients with Sickle Cell Anemia

Background: Sickle cell anemia (SCA) is associated with cognitive challenges that often worsen as children age. Previous work has established relationships between hematological markers of disease severity (i.e., hemoglobin concentration) and various neurological outcomes, including cognitive impairment. However, most studies have related static, often isolated hemoglobin concentration (Hb) values obtained from a single time-point closest to data collection. Studies of pediatric patients with phenylketonuria and Type I diabetes have demonstrated that longitudinal change and variability in phenylalanine and glucose, respectively, are better indicators of neurological and cognitive outcomes than a single value alone. Our study aimed to be the first study of pediatric patients with SCA to examine the extent to which indices of Hb control (e.g., lifetime average and variability), collected routinely in this patient group, may provide additional prognostic information.Methods: Data were collected from pediatric patients (aged 4-18 years at enrolment) with and without SCA enrolled on the Sleep Asthma Cohort-III (SAC-III) follow-up study. SAC is a mixed retrospective-prospective study assessing the impact of nocturnal oxygen desaturation on SCA complications. The present investigation assessed participants (see Figure 1 for complete participant demographics) who underwent cognitive evaluation using Wechsler scales measuring domains of IQ, processing speed (i.e., processing speed index [PSI] and Cancellation subtest), and executive function (working memory index [WMI]). Participant demographics and appropriate medical data and history (i.e., hydroxyurea therapy, silent infarction) were obtained via questionnaires and analysis of medical records. Hb (d/L) measures assessed included average lifetime values (i.e., mean and median), variability over the lifetime (i.e., standard deviation), and the single value obtained closest to data collection.Results: Correlation analyses indicated a strong positive relationship between the mean and median Hb values along with large positive associations between the average and contemporaneous values. Small non-significant correlations were demonstrated between variability and average Hb values (see Figure 1). Initial hierarchical linear regression analyses demonstrated that neither hydroxyurea use nor silent infarct (SCI) status were predictors of any cognitive outcomes or Hb values, so they were not included in any further analyses. Separate regression analyses for each cognitive outcome found that mean lifetime Hb values was the only significant predictor of IQ (p = .04, η 2 = .13) and the Cancellation subtest (p = .005, η 2 = .22). Mean lifetime Hb values approached significance for PSI (p = .09, η 2 = .08), but was not a predictor for WMI (p = .33, η 2 = .03).Conclusion: Our study demonstrated that despite strong correlations between Hb obtained closest to testing and average lifetime values (i.e., rs = .64 and .69), only lifetime Hb predicted cognitive outcomes, particularly processing speed scores from the Cancellation subtest. Variability was not strongly related to other indices of Hb control and did not predict any cognitive outcomes. These results mirror those obtained from other pediatric populations indicating that static, one time values may not best represent clinical manifestations of chronic illness, and the choice of Hb value can differentially influence research study results and clinical prognosis. Future longitudinal work in larger samples is needed, but Hb obtained over the lifetime appears to provide a more precise picture of patients' cognitive developmental trajectory than a single contemporaneous Hb value alone. [Display omitted] DisclosuresKirkham: Bluebird Bio: Honoraria; Novartis: Honoraria; Global Blood Therapeutics: Consultancy. Howard: Imara: Consultancy, Honoraria; Global Blood Therapeutics: Consultancy; Novartis: Consultancy, Honoraria; Resonance Health: Honoraria; Novo Nordisk: Consultancy; Agios Pharmaceuticals: Consultancy; Forma Therapeutics: Consultancy; Bluebird Bio: Research Funding.

COPD sleep phenotypes: Genesis of respiratory failure in COPD.

The chronic obstructive pulmonary disease (COPD) patients could have respiratory failure during sleep without daytime overt arterial blood gas (ABG) abnormality. We undertook a study first of its kind to attempt in distinguishing the underlying pathophysiological mechanisms. It was a prospective observational study in stable COPD patients. The inclusion criterion was presence of day time PaO2>60 mmHg and PaCO2<45 mmHg. Twenty five out of 110 patients were excluded because of the ABG abnormality. The remaining 85 patients were subjected to overnight pulse oximetry and end-tidal (ET)-CO2 monitoring. The nocturnal oxygen desaturation was defined as per Fletcher's criteria. The nocturnal hypoventilation was defined as per American academy of sleep medicine (AASM) guidelines. Patients having saw-tooth pattern on pulse oximetry and/or snoring were subjected to polysomnography. 38/85(44.8%) patients had nocturnal gas exchange abnormality in absence of daytime respiratory failure and were identified into 3 different phenotypes: obstructive sleep apnoea (OSA), nocturnal hypoventilation and nocturnal oxygen desaturation. The isolated abnormality was seen in 24 patients: 10 patients had OSA, 9 had nocturnal hypoventilation and 5 had nocturnal oxygen desaturation. Overlap of two or more phenotypes was seen in 14 patients. As compared to the nocturnal hypoventilation and desaturation phenotypes, the OSA phenotype had a significantly higher BMI & FEV1. The nocturnal hypoventilation and the desaturation phenotypes did not have significant difference in FEV1 and BMI, but the daytime SpO2 and PaO2 differed significantly. Such parameters could help in identifying the three distinct COPD-sleep phenotypes (OSA, nocturnal hypoventilation and nocturnal oxygen desaturation). A phenotype based nocturnal management may help in delaying the process of overt respiratory failure in COPD.

Hypercapnia-induced vasodilation in the cerebral circulation is reduced in older adults with sleep-disordered breathing.

The prevalence of sleep-disordered breathing (SDB) is higher in older adults compared with younger individuals. The increased propensity for ventilatory control instability in older adults may contribute to the increased prevalence of central apneas. Reductions in the cerebral vascular response to CO2 may exacerbate ventilatory overshoots and undershoots during sleep. Thus, we hypothesized that hypercapnia-induced cerebral vasodilation (HCVD) will be reduced in older compared with younger adults. In 11 older and 10 younger adults with SDB, blood flow velocity in the middle cerebral artery (MCAV) was measured using Doppler transcranial ultrasonography during multiple steady-state hyperoxic hypercapnic breathing trials while awake, interspersed with room air breathing. Changes in ventilation, MCAV, and mean arterial pressure (MAP) via finger plethysmography during the trials were compared with baseline eupneic values. For each hyperoxic hypercapnic trial, the change (Δ) in MCAV for a corresponding change in end-tidal CO2 and the HCVD or the change in cerebral vascular conductance (MCAV divided by MAP) for a corresponding change in end-tidal CO2 was determined. The hypercapnic ventilatory response was similar between the age groups, as was ΔMCAV/Δ[Formula: see text]. However, compared with young, older adults had a significantly smaller HCVD (1.3 ± 0.7 vs. 2.1 ± 0.6 units/mmHg, P = 0.004). Multivariable analyses demonstrated that age and nadir oxygen saturation during nocturnal polysomnography were significant predictors of HCVD. Thus, our data indicate that older age and SDB-related hypoxia are associated with diminished HCVD. We hypothesize that this impairment in vascular function may contribute to breathing instability during sleep in these individuals.NEW & NOTEWORTHY This study demonstrates, for the first time, in individuals with sleep-disordered breathing (SDB) that aging is associated with decreased hypercapnia-induced cerebral vasodilation (HCVD). In addition to advanced age, the magnitude of nocturnal oxygen desaturation due to SDB is an equal independent predictor of HCVD.

Eat, breathe, sleep with Osteogenesis Imperfecta

BackgroundAlthough Osteogenesis Imperfecta (OI) affects the connective tissue causing extremely brittle bones with consequent skeletal deformities, it is important to go beyond bones. Indeed, the quality of life in OI does not only depend on bones status, as OI might affect also other important functions. We have therefore implemented a multidisciplinary study to assess lung function, breathing pattern, sleep quality and nutritional status in 27 adult OI type III and IV patients (median age: 34.6 years; 19 women; 14 type III).ResultsAccording to nocturnal oxygen desaturation, two groups were identified: 13 patients with (OI_OSA, incidence: 48.2%) and 14 without (no_OSA) obstructive sleep apnea. The former was characterized by higher spinal and ribcage deformity, by more restrictive lung function, by paradoxical thoracic breathing in supine position, by rapid and shallow breathing, by higher body mass index, by longer neck and waist circumferences; by higher abdominal volume and by greater percentage of body fat mass, particularly localized in the trunk.The best predictor of OI_OSA was the negative value of the supine ribcage contribution to tidal volume, followed by the ratio between the neck and the waist circumferences with body height and the supine thoraco-abdominal volumes phase shift angle.ConclusionsThe pathophysiology of OI ensued a dangerous vicious circle, in which breathing, sleep and nutritional status are tightly linked, and they might all end up in negatively affecting the quality of life. The vicious circle is fed by some intrinsic characteristics of the disease (thoracic, cranial and mandibular deformities) and some bad daily habits of the patients (i.e. physical inactivity and low dietary quality). The former impacts on restricting the respiratory function, the latter makes Olers more prone to experience overweight or obesity. The main consequence is a high incidence of obstructive sleep apnea, which remains an underdiagnosed disorder in individuals with severe OI who are obese, with a neck to height ratio over than 31.6%, and characterized by paradoxical breathing in supine position. A multidisciplinary approach, including evaluations of breathing, sleep and nutrition, is required to better manage the disease and fulfil the maximizing well-being of OI patients.

P138 Nocturnal oxygen desaturation and MET call criteria during in-laboratory sleep studies

Abstract Introduction Patients undergoing sleep studies can experience frequent and profound oxygen desaturation. Most hospitals have standard MET (Medical Emergency Team) call criteria which obligate a response to severe oxygen desaturation. At our tertiary institution this is “Pulse oximetry/oxygen saturation: &amp;lt; 90 despite oxygen administration”. For most sleep studies provision of oxygen overnight would not be appropriate. We sought to examine the proportion of our sleep study patients who would meet MET call criteria. Method We retrospectively examined the data of all sleep studies which were performed in our laboratory between 01/01/2021 and 30/04/2021. Demographic and pulse oximetry data was collected. Results We collected data from 448 studies (95 CPAP, 342 diagnostic, 9 Split, 2 other). Patients were 40% female, 49±15 (mean±SD) years old and had a median AHI of 10 events per hour. 290 (65%) patients had a nadir SpO2 of &amp;lt;90%. The percentage of patients below with nadir SpO2 of 80%, 70%, 60% and 50% was 20%, 9%, 5% and 3% respectively. These proportions did not significantly change if treatment studies were excluded. In contrast, 23 (5%) of patients had a mean overnight SpO2 &amp;lt; 90%. During the period studied no serious adverse event was recorded. Discussion Most patients presenting for a sleep study to our tertiary institution would potentially meet standard hospital MET call criteria. This demonstrates the need for hospitals to be flexible in terms of hospital wide protocols when it comes to sleep laboratories. Evidence based criteria for medical escalation in sleep laboratories are required.