Minimum SpO2 Research Articles

Ventricular arrhythmias in a patient with obstructive sleep apnea syndrome and its effective non-pharmaceutical treatment

Patients with obstructive sleep apnea syndrome (OSAS) are characterized by various cardiac arrhythmias during sleep. However, while the association between OSAS and atrial fibrillation is considered proven, the presence of a pathophysiological link between sleep apnea and ventricular arrhythmias remains a matter of debate.We present a case of a 51-year old man with arterial hypertension and type 2 diabetes who was referred for sleep assessment after being diagnosed with predominantly nocturnal cardiac arrhythmias. Overnight cardiorespiratory monitoring showed that the patient had a severe OSAS with an apnea-hypopnea index of 57 per hour and a minimal SpO2 during sleep of 73%. On the channel of electrocardiogram (ECG) frequent single monomorphic ventricular extrasystoles, eventually of the bigeminal type, and one short paroxysm of a wide-complex regular rhythm of 60 beats per minute (accelerated idioventricular rhythm) associated with prolonged apnea were identified. Continuous airway positive pressure (CPAP) therapy was started which was able to control for breathing disorders during sleep. At the follow-up 24-hours Holter ECG monitoring, the numbers of ventricular extrasystoles during sleep decreased 2-fold, without any idioventricular rhythm episodes.The clinical case clearly illustrates that in some patients with OSAS, first of all, in those with severe OSAS and comorbid cardiovascular disorders, breathing disorders during sleep can trigger ventricular arrhythmias. In such patients, CPAP therapy could both improves their quality of life and provide an indirect antiarrhythmic effect.

Long-Term Decreased Exercise Capacity of COVID-19 Patients Who Received Mechanical Ventilation in Japan: A Case Series.

The long-term exercise capacity of coronavirus disease 2019 patients with acute respiratory distress syndrome is not clear. The 6-min walking distance of four patients with coronavirus disease 2019-associated acute respiratory distress syndrome was followed for 6 mos after admission to the hospital. These four patients were admitted to the intensive care unit of our hospital and received mechanical ventilation. Rehabilitation therapy (positioning, postural drainage, and passive range-of-motion exercises) was started after intensive care unit admission. Mobilization therapy, including muscle power training, sitting on the edge of the bed, and endurance training, was performed after the end of sedation. The Medical Research Council sum scores and Barthel Indexes for the patients improved after intensive care unit discharge and completely recovered 6 mos after admission to the hospital. However, the 6-min walking distance of the four patients remained shorter than those of healthy persons of the same age at 6 mos after admission to the hospital. Furthermore, the minimum Spo2 during the 6-min walking test remained less than 96%. It is possible that patients who receive mechanical ventilation due to coronavirus disease 2019-associated acute respiratory distress syndrome have decreased long-term exercise capacity, despite muscle power and activities of daily living recovering completely.

Different Associations between Tonsil Microbiome, Chronic Tonsillitis, and Intermittent Hypoxemia among Obstructive Sleep Apnea Children of Different Weight Status: A Pilot Case-Control Study.

The tonsil microbiome is associated with chronic tonsillitis and obstructive sleep apnea (OSA) in children, and the gut microbiome is associated with host weight status. In this study, we hypothesized that weight status may be associated with clinical profiles and the tonsil microbiome in children with OSA. We prospectively enrolled 33 non-healthy-weight (cases) and 33 healthy-weight (controls) pediatric OSA patients matched by the proportion of chronic tonsillitis. Differences in the tonsil microbiome between the non-healthy-weight and healthy-weight subgroups and relationships between the tonsil microbiome and clinical variables were investigated. Non-healthy weight was associated with significant intermittent hypoxemia (oxygen desaturation index, mean blood saturation (SpO2), and minimal SpO2) and higher systolic blood pressure percentile, but was not related to the tonsil microbiome. However, chronic tonsillitis was related to Acidobacteria in the non-healthy-weight subgroup, and oxygen desaturation index was associated with Bacteroidetes in the healthy-weight subgroup. In post hoc analysis, the children with mean SpO2 ≤ 97% had reduced α and β diversities and a higher abundance of Bacteroidetes than those with mean SpO2 > 97%. These preliminary findings are novel and provide insights into future research to understand the pathogenesis of the disease and develop personalized treatments for pediatric OSA.

Microcirculatory Responses to Muscle and Tendon Exercises in Individuals With and Without Type 2 Diabetes Mellitus and the Association Between Microcirculatory and Exercise Performance.

Background: This study aimed to measure and compare (1) the microcirculation and microcirculatory responses of the muscles and tendons at rest and during isometric muscle contractions in participants with and without diabetes mellitus (DM) and (2) to determine correlations between microcirculation and muscle strength. Methods: Sixty-three participants with type 2 DM and 42 physically matched controls were recruited. Baseline measurements of the microcirculation of the rectus femoris (RF) and medial gastrocnemius (MG) muscles and patellar (PT) and Achilles tendons (AT), as well as their microcirculatory changes during maximal isometric exercises, were performed and recorded by using near-infrared spectroscopy and a red laser. Data on various laboratory tests (including glycated hemoglobin, triglyceride, high-density cholesterol), the monofilament test, and the ankle-brachial index were also obtained. Results: The baseline measurements indicated that, compared with the controls, the diabetic participants had lower oxygen saturation (SpO2) in their RF and MG muscles (both P < 0.001), and the total hemoglobin in the diabetic PT and AT was higher (P = 0.001 and P = 0.01). The minimal SpO2 levels in the aforementioned muscles during isometric contractions were lower in the diabetes group than in the control group (P ≤ 0.001). Furthermore, there were correlations between the microcirculatory change of the RF muscle and the knee extension force. Conclusions: This study demonstrated the effects of diabetes on the microcirculation of skeletal muscles and tendons during baseline measurements and responses to maximal isometric exercises. The results support the need for preventive strategies for diabetic muscles to prevent adverse complications when performing resistance training.

Perioperative adherence to continuous positive airway pressure and its effect on postoperative nocturnal hypoxemia in obstructive sleep apnea patients: a prospective cohort study

BackgroundAlthough continuous positive airway pressure (CPAP) is the first line treatment for obstructive sleep apnea (OSA) patients, the perioperative adherence rate is unclear. The objective of this study was to determine the perioperative adherence rate of patients with OSA with a CPAP prescription and the effect of adherence on nocturnal oxygen saturation.MethodsThis prospective cohort study included adult surgical patients with a diagnosis of OSA with CPAP prescription undergoing elective non-cardiac surgery. Patients were divided into CPAP adherent and non-adherent groups based on duration of usage (≥ 4 h/night). Overnight oximetry was performed preoperatively and on postoperative night 1 and 2 (N1, N2). The primary outcome was adherence rate and the secondary outcome was nocturnal oxygen saturation.ResultsOne hundred and thirty-two patients completed the study. CPAP adherence was 61% preoperatively, 58% on postoperative N1, and 59% on N2. Forty-nine percent were consistently CPAP adherent pre- and postoperatively. Using a linear fixed effects regression, oxygen desaturation index (ODI) was significantly improved by CPAP adherence (p = 0.0011). The interaction term CPAP x N1 was significant (p = 0.0015), suggesting that the effect of CPAP adherence varied on N1 vs preoperatively. There was no benefit of CPAP adherence on postoperative mean SpO2, minimum SpO2, and percentage of sleep duration with SpO2 < 90%. Use of supplemental oxygen therapy was much lower in the CPAP adherent group vs non-adherent group (9.8% vs 46.5%, p < 0.001).ConclusionsAmong patients with a preoperative CPAP prescription, approximately 50% were consistently adherent. CPAP adherence was associated with improved preoperative ODI and the benefit was maintained on N1. These modest effects may be underestimated by a higher severity of OSA in the CPAP adherent group and a higher rate of oxygen supplementation in the non-adherent group.Trial registrationClinicalTrials.Gov registry (NCT02796846).

A role for cardiopulmonary exercise testing in detecting physiological changes underlying health status in Idiopathic pulmonary fibrosis: a feasibility study

IntroductionThere is limited data available on the use of CPET as a predictive tool for disease outcomes in the setting of IPF. We investigated the feasibility of undertaking CPET and the relationship between CPET and quality of life measurements in a well-defined population of mild and moderate IPF patients.MethodsA prospective, single-centre observational study.ResultsThirty-two IPF patients (mild n = 23, moderate n = 9) participated in the study, n = 13 mild patients attended for repeat CPET testing at 12 months. At baseline, total K-BILD scores and total IPF-PROM scores significantly correlated with 6MWT distance, but not with baseline FVC % predicted, TLco % predicted, baseline or minimum SpO2. VO2 peak/kg at AT positively correlated with total scores, breathlessness/activity and chest domains of the K-BILD questionnaire (p < 0.05). VO2 peak significantly correlated with total IPF PROM scores and wellbeing domains (p < 0.05), with a trend towards statistical significance for total IPF-PROM and VO2 peak/kg at anaerobic threshold (p = 0.06).There was a statistically significant reduction in FVC% predicted at 12 months follow up, although the mean absolute decline was < 10% (p < 0.05). During this period VO2 peak significantly reduced (21.6 ml/kg/min ± 2.9 vs 19.1 ± 2.8; p = 0.017), with corresponding reductions in total K-BILD and breathlessness/activity domains that exceeded the MCID for responsiveness. Lower baseline VO2 peak/kg at anaerobic threshold correlated with greater declines in total K-BILD scores (r = − 0.62, 0.024) at 12 months. Whilst baseline FVC% predicted or TLco % predicted did not predict change in health status,ConclusionWe have shown that it is feasible to undertake CPET in patients with mild to moderate IPF.CPET measures of VO2 peak correlated with both baseline and change in K-BILD measurements at 1 year, despite relatively stable standard lung function (declines of < 10% in FVC), suggesting its potential sensitivity to detect physiological changes underlying health status.

566 Persistent Sleep Apnea and Desaturation in Preterm Children at 18 Months of Age at High Altitude (2640 M)

Abstract Introduction Children born at term who live at high altitude (HA) (≥ 2500 m) have different respiratory patterns from those that live at sea level. It is essential to determine these patterns in preterm children due to their high risk of Sleep Apnea-Hypopnea Syndrome (SAHS). The evolution of the apnea hypopnea index (AHI), desaturation index (ODI), and oxygen saturation (SpO2) is unknown in this group at HA. The objective was to characterize the respiratory patterns during sleep of preterm children living at HA and compare it with those of healthy children born at term. Methods We conducted a cross-sectional study in Bogotá, Colombia (altitude: 2640 m). We included 302 children, 127 were preterm with an average of gestational age of 31weeks (SD: 2.9) and an average weight at birth of 1600 g (SD: 594) and 175 healthy full-term infants. Three groups were defined according to age: Group I: 3–4 months, Group II: 6–7 months,, Group III: 10–18 months. All children underwent nocturnal polysomnogram to evaluate their respiratory variables: AHI, average and minimum SpO2, ODI, and T90 during sleep and analyzed the data according to the parameters of the American Academy of Sleep Medicine Results 302 polysomnograms were performed, 54.3% were girls and were distributed by groups as follows: Group I:105 patients (34.8%), 16 preterm, Group II: 107 patients (35.4%), 46 preterm and Group III: 90 patients (29.8%), 65 preterm. We observed higher respiratory parameters within each age strata in premature infants compared to children born at term. Preterm infants had higher ODI, AHI, obstructive apnea hypopnea index (O-AHI), and Central Apnea hypopnea index (C-AHI). Although the effect decreases over time, we found a significant difference in the first age group. There was a high persistence index in children with a history of preterm birth living at high altitude. We also found a significant decrease in AHI, ODI across time in healthy and preterm children p&amp;lt;0.01 Conclusion Premature children living at HA persist with higher ODI and AHI compared to children of similar ages born at term. The high desaturation index indicates the presence of intermittent hypoxia that persists in these children over time Support (if any):

245 Sleep and cortical thickness are influenced by surgical menopause

Abstract Introduction Early loss of 17β-estradiol (E2), as experienced by women with bilateral salpingo-oophorectomy (BSO; removal of ovaries and fallopian tubes), is associated with increased prevalence of sleep disorders and greater Alzheimer’s disease (AD) risk. In older adults, poor sleep heightens AD risk; hypoxia increases markers for incipient AD, including circulating Aβ, and is linked to prefrontal cortical thinning. Thus, we wondered: 1) if this at-risk population of middle-aged women with BSO had sleep hypoxia, measured by oxygen desaturation, and 2) whether this related to decreased prefrontal cortical thickness in women taking and not taking estradiol therapy (ET). Methods Sleep and percent oxygen desaturation (SPO2%) were measured via at-home polysomnography (TEMEC). Prefrontal cortical thickness was obtained from T1-weighted structural scans using the CIVET pipeline. We recruited middle-age women with BSO, some of whom were taking ET (BSO+ET; n=15), and some not (BSO; n=15). We compared their sleep and cortical thickness with that of age and education-matched premenopausal controls (AMC; n=18). Results Women with BSO (BSO, BSO+ET) had lower minimum SPO2% values than AMC, and thinner right medial orbitofrontal (rmOF) cortices. There was a trend for women with BSO to have lower average SPO2% than AMC. Analyses separating groups based on ET therapy status (BSO vs BSO+ET vs AMC) revealed only trending differences between groups, such that women with BSO tended to have lower minimum SPO2% and thinner rmOF cortices than AMC. Conclusion These preliminary results suggest early loss of E2 due to BSO may drive greater drops in SPO2% in middle-age women, and may be related to reduced prefrontal cortical thickness. This study is the first to show hypoxia in women with BSO. Support (if any) Ontario Graduate Scholarship Award (to LG), Alzheimer’s Association Research Fellowship (co-sponsored by Brain Canada Foundation; AARF-17-504715 to NJG), Alzheimer’s Society Canada Postdoctoral Fellowship (to AA), Canadian Institutes of Health Research (CIHR) Masters Award (to LG, AB, and RR), Wilfred and Joyce Posluns Chair in Women’s Brain Health and Aging (from the Posluns Family Foundation, CIHR, Ontario Brain Institute, and Alzheimer Society of Canada; WJP-150643 to GE)

Evaluation of the relationship between polysomnography parameters, physical examination findings and oxidative stress parameters in patients with obstructive sleep apnea syndrome

Background/Aim: Oxidative stress status in obstructive sleep apnea syndrome (OSAS) is well discussed in the literature. Oxidative stress levels increase, and antioxidant system activi-ty decreases in OSAS patients. However, the change in oxidative stress status in positional (pOSAS) and non-positional (npOSAS) OSAS has not been adequately examined. The aim of this study was to compare OSAS patients’ polysomnographic (PSG) parameters and oxidative stress capacities with the structural and functional properties of the upper respiratory tract. Methods: This study was designed as prospective case-control study and patients were divided into three groups as control, pOSAS and npOSAS according to their PSG findings. Ear nose throat examinations including rhinomanometry test and oxidative stress blood parameter tests were conducted to all patients. Variables among the groups were compared. Results: All PSG parameters were significantly worse in the OSAS groups than the control group (P<0.05). The mean AHIs of the pOSAS and npOSAS groups were 21.7 (16.5), and 31.2 (21.9), respectively. AHI, desaturation number and minimal SpO2 values of the pOSAS group were significantly lower compared to the npOSAS group (P=0.043, P=0.017 and P=0.006, respectively). TNF α was significantly lower and adiponectin was significantly higher in the pOSAS group compared to the npOSAS group (P=0.001, P<0.001 respectively). The two groups were similar in terms of rhinomanometry results (P=0.888). Conclusion: The lack of difference between pOSAS and npOSAS patients in terms of rhinomanometry results may indicate that the nose may not play a decisive role in the differentiation of these groups. Only OSAS severity may not be a determinant factor in oxidative stress balance in patients with pOSAS and np OSAS.

Efficacy, predictors of success and failure of an updated lateral pharyngoplasty approach as an independent procedure in treating obstructive sleep apnea with CPAP failures.

To assess predictors of success and failure of an updated lateral pharyngoplasty as an independent procedure in treating obstructive sleep apnea with CPAP failures. Forty-six patients with known OSAS who were resistant to CPAP or failures were included. BMI, Stop-Bang score, and sleep study data were recorded before and after the updated Cahali pharyngoplasty procedure. Pre-operative DISE was done for all cases; however, postoperative DISE was done only for non-responders. Successful operation outcomes achieved in 69.6% (32 cases) and 30.4% (14 cases) were failure rates. Postoperative snoring index, Stop Bang score, and AHI were significantly decreased compared to pre-operative data (p value < 0.001). There is statistically a significant increase in minimal and baseline SpO2 postoperatively (p value < 0.001). Patients with no laryngeal collapse (L0) predict operation success. However, patients with high pre-operative snoring index, collapse at lateral wall hypopharynx, high tongue collapse, laryngeal collapse, tongue palate interaction, and low grades tonsils (1, 2) predict the failure of the surgery (p value = 0.006*,0.024*,0.047*, respectively). Updated Cahali lateral pharyngoplasty could not be used as an independent procedure in all OSA patients. The lack of laryngeal collapse (L0) is a considerable success predictor for the procedure. However, the pre-operative low-grade tonsils (1, 2) and high snoring index predict operation failure.

Comparison of Oxygen Saturation Between Nasal High-Flow Oxygen and Conventional Nasal Cannula in Obese Patients Undergoing Dental Procedures With Deep Sedation: A Randomized Crossover Trial

PurposeIn anesthetic management, it is widely accepted that obese patients are more likely to suffer airway obstructions and reductions in arterial oxygen saturation (SpO2). Therefore, it is important to take special measures to prevent oxygen desaturation during the deep sedation of obese patients. This clinical study examined whether the use of nasal high-flow systems (NHFS) keep higher SpO2 and reduced hypoxemia than conventional nasal cannula during the deep sedation of obese patients with intellectual disabilities for dental treatment. Materials and MethodsEighteen obese patients (body mass index: >25) with intellectual disabilities who underwent dental sedation were enrolled. In each case, sedation was induced using propofol and maintained at a bispectral index of 50 to 70. The subjects were randomly assigned to the control oxygen administration (5 L/min via a nasal cannula) or NHFS (40% O2, 40 L/min, 37 °C) arm in alternate shifts as a crossover trial. The primary endpoint was the minimum SpO2 value, and the incidence of hypoxemia during dental treatment was also evaluated. ResultsThe mean minimum SpO2 value was significantly higher in the NHFS arm than in the control arm (95.8 ± 2.1 % vs 93.6 ± 4.1 %, P = 0.0052, 95% confidence interval: 0.608-3.947). Hypoxemic episodes (SpO2: ≤94%) occurred 3 cases (16.7%) in the NHFS arm and 11 cases (61.1%) in the control arm (P = 0.0076, odds ratio: 0.127, 95% confidence interval 0.0324 - 0.630). ConclusionNHFS resulted in higher minimum SpO2 and reduced hypoxemia than nasal cannula in obese patients during deep sedation for dental treatment.

Audit of oxygen administration to achieve a target oxygen saturation range in acutely unwell medical patients

Purpose of the studyTo evaluate documentation of a target oxygen saturation (SpO2) range and ability to achieve this range in acutely unwell inpatients.Study designIn this single-centre audit, patients with discharge...

Obstructive Sleep Apnea as a Risk Factor of Insulin Resistance in Nondiabetic Adults.

Objective: The aim of this research was to assess the relationship between prevalence and severity of obstructive sleep apnea (OSA) and insulin resistance among patients with increased risk of OSA without diabetes mellitus. Method and materials: our study group involved 102 individuals with suspected OSA, mean age 53.02 ± 12.37 years. Data on medical history, medication usage, sleep habits, sleep quality and daytime sleepiness, were obtained using questionnaires. All patients underwent standardized full night polysomnography. Serum fasting insulin and glucose concentration were analyzed, the homeostatic model assessment-insulin resistance (HOMA-IR) index was calculated. Results: polysomnographic study indicated that in the group with OSA mean values of apnea–hypopnea index (AHI), oxygen desaturation index (ODI), duration of SpO2 < 90% and average desaturation drop were significantly higher compared to the group without OSA, while the minimum SpO2 was significantly lower. The carbohydrate metabolism parameters did not differ within those groups. Significantly higher fasting insulin concentration and HOMA-IR index were found in the group with AHI ≥ 15 compared to the group with AHI < 15 and in the group with AHI ≥ 30 compared to the group with AHI < 30. Higher AHI and ODI were independent risk factors for higher fasting insulin concentration and higher HOMA-IR index. Increased duration of SpO2 < 90% was an independent risk factor for higher fasting glucose concentration. Conclusions: Individuals with moderate to severe OSA without diabetes mellitus had a higher prevalence of insulin resistance.

Validation of a breath-holding test as a screening test for exercise-induced hypoxemia in chronic respiratory diseases.

The detection of exercise-induced hypoxemia is important for evaluating disease status in patients with chronic respiratory diseases. The 6-min walk test (6MWT) is useful for detecting exercise-induced hypoxemia. This pilot study aimed to validate the breath-holding test (BHT) as a screening for exercise-induced hypoxemia and compare its utility with that of the 6MWT in patients with chronic respiratory diseases. Fifty-nine patients with chronic respiratory diseases underwent BHTs lasting 10, 15, and 20 s. Percutaneous oxygen saturation (SpO2), pulse rate, and severity of dyspnoea were measured. The participants also underwent a 6MWT, a pulmonary function test, and analysis of arterial blood gas at rest. Multivariate linear regression analysis was performed to identify significant predictors of desaturation in the 6MWT. The minimum SpO2 during the BHT (all durations) and 6MWT were significantly correlated. Receiver operating characteristic analysis revealed the optimal cut-off for predicting SpO2 < 90% during the 6MWT as a minimum SpO2 ≤ 94% during the 15-s BHT. Perceived dyspnoea and maximum pulse rate were significantly lower during the 15-s BHT than during the 6MWT. In the multivariate linear regression analysis, the minimum SpO2 during the 15-s BHT (β, 0.565, p < 0.001) and %DLco (β, 0.255, p < 0.028) were independent predictors of desaturation in the 6MWT. The minimum SpO2 during the 15-s BHT may be a useful measure for screening for exercise-induced hypoxemia in patients with chronic respiratory diseases. The BHT is easier to perform, more readily available, and better tolerated than the 6MWT.

Association of lower nighttime diastolic blood pressure and hypoxia with silent myocardial injury: The Japan Morning Surge-Home Blood Pressure study.

Whether marked nocturnal blood pressure (BP) reduction is associated with cardiovascular disease (CVD) is still controversial. In addition, no report has yet discussed the relationship between lower nocturnal BP and CVD, involving modification by nighttime hypoxia. We evaluated 840 patients who had one or more cardiovascular risk factors by measuring their high‐sensitivity cardiac troponin T (Hs‐cTnT), N‐terminal pro‐B‐type natriuretic peptide (NT‐pro BNP), and nighttime saturation levels and performing ambulatory BP monitoring. The lowest tertile in nighttime diastolic BP (DBP) (≤66 mmHg) had increased likelihood of the presence of ≥0.014 ng/ml of Hs‐cTnT compared with the second tertile (odds ratio [OR] 1.91, 95% confidence interval [CI] 1.01–3.63), and the lowest tertile of minimum blood oxygen saturation (≤81%) had increased likelihood of the presence of ≥0.014 ng/ml of Hs‐cTnT compared with the third tertile (OR 2.15, 95% CI 1.13–4.10). Additionally, the patients with both lowest tertile of nighttime DBP and minimum SpO2 showed increased likelihood of the presence of ≥0.014 ng/ml of Hs‐cTnT compared with those without this combination (OR 2.93, 95% CI 1.40–6.16). On the other hand, these associations were not found in the presence of ≥125 pg/ml of NT‐pro BNP. In the clinical population, each of lower nocturnal DBP and nighttime hypoxia was associated with asymptomatic myocardial injury, which was represented as higher Hs‐cTnT, and coexisting lower nocturnal DBP and nighttime hypoxia had an additive effect on the risk of myocardial injury.

Tim-3 is a potential regulator that inhibits monocyte inflammation in response to intermittent hypoxia in children with obstructive sleep apnea syndrome

The mechanism of the characteristic intermittent hypoxia (IH) of obstructive sleep apnea syndrome (OSAS) on monocyte remain unclear. Our study found that OSAS children had a significantly upregulated expression in circulating proinflammatory cytokines IL-6 and IL-12, and endothelial injury markers VEGF and ICAM1. Association analysis revealed that the plasma TNFα, IL-1β, IL-6, IL-10 and IL-12 concentration were negatively associated with the minimal SpO2, a negative index for disease severity. OSAS monocytes presented an inflammatory phenotype with higher mRNA levels of inflammatory cytokines. Importantly, we noted a significant decrease in T-cell immunoglobulin and mucin domain (Tim)-3 expression in OSAS monocytes with the increase of the plasma proinflammatory cytokines. In vitro assay demonstrated that IH induced THP-1 cell overactivation via NF-κB dependent pathway was inhibited by the Tim-3 signal. Our results indicated that activation of monocyte inflammatory responses is closely related to OSAS-induced IH, and negatively mediated by a Tim-3 signaling pathway.

Does chronic rhinosinusitis relate to systemic hypoxemia?

ObjectivesDetermine if chronic rhinosinusitis (CRS) is associated with systemic hypoxemia.MethodsOutpatient otolaryngology visits for 12 months were analyzed, identifying patients with a diagnosis of CRS, without a comorbid diagnosis of pulmonary disease, and an oxygen saturation measurement within 14 days of the otolaryngology visit. Oxygen saturation (SpO2) measures (average SpO2, minimum SpO2 and proportion abnormal SpO2) were compared between CRS patients (with nasal polyps [NP] and without NP) and a control cohort of otology patients, also without pulmonary disease with univariate and multivariate analysis.ResultsAmong 640 unique CRS patients with 3105 encounters, the mean and minimum SpO2 measurements were 97.6% (97.5%‐97.7%) and 97.3% (97.2%‐97.5%), respectively. Among 3613 control patients with 25 073 encounters, the mean and minimum SpO2 measurements were 97.3% (97.3%‐97.4%) and 97.1% (97.1%‐97.2%), respectively. When comparing mean and minimum SpO2 among CRSsNP (97.5% and 97.2%), CRScNP (97.3% and 97.0%) and control patients (97.3% and 97.1%), no statistically significant differences were found among the 3 groups in mean and minimum SpO2 adjusting for age and sex (P = .183 and P = .464, respectively, ANOVA). With respect to the presence of an abnormally low oxygen saturation (SpO2 ≤ 94%), 4.4% of the CRSsNP, 10.9% of the CRScNP and 7.3% of the control patients demonstrated a low oxygen saturation (P = .013).ConclusionCRS alone does not objectively contribute to systemic hypoxemia, although a subset of CRScNP patients may have abnormally low SpO2, possibly warranting SpO2 assessment in this group of patients.Level of evidence3.

Clinical utility of oximetric parameters to identify a high‐risk phenotype of moderate‐severe Obstructive Sleep Apnea (OSA)

Toanalyzed oximetric variables in patients with moderate-severe OSA to assess their predictive value regardingas hypertension, type 2 diabetes mellitus (T2DM),coronary heartdisease (CHD) and CV mortality. Using data from SantOSA cohort, we develop receiver operating characteristic curve and area under the curve (AUC) for each parameter,defining theproposed cutoff point in a training set. Then, in a validation set with a 5years follow-up, we evaluatetheclinicaldifferencesbetween groups usingtheproposed cutoff. We also calculated adjusted Hazard Ratios (HR) of mortality using a Cox regression model. About 965 patients with moderate-severe OSA (525 in training and 440 in validation group) were included.The bestAUC was achieved with T90 (AUC=0.66) and ODI (AUC=0.61). Proposed cutoffs of T90 were hypertension: 10%, T2DM: 20%, CHD: 15%, meanwhile, proposed cutoff ofODI was≥30 ev for hypertension and T2DM. Regarding CV mortality,T90≥20% was independentlyassociated with anadjusted HR 2.44 (CI, 1.21-4.94),P-value=0.01, meanwhile, ODI≥30 ev. reported and adjusted HR 1.59 (CI, 0.75-3.39),P-value=0.22. In patients with moderate-severe OSA, oximetric parameters, especially T90≥20% remained a predictor of mortality after adjusting for a range of demographic and disease predictors.

Sensitivity analysis of a computer model of neonatal oxygen transport

Abstract Computer models of neonatal oxygenation could serve as a tool for a comprehensive comparison of closed-loop automated oxygen control systems. The behaviour of such models depends, besides the input data of the inspired fraction of oxygen and the premature infant's breath pattern, on internal parameters of the model. The aim of this study was to perform a sensitivity analysis of a computer model of neonatal oxygen transport to clarify the influence of its internal physiological parameters on the output signal of peripheral oxygen saturation (SpO2). We performed a multi-parameter sensitivity analysis using Monte Carlo simulations for randomly generated values of eight internal parameters. The influence on the model output SpO2 signal was evaluated using five characteristics of the output signal. The relations between the parameters and the output characteristics were displayed using scatter plots and analysed by linear correlation, standardized regression, and partial correlation. The main result of the study is that in our model the oxygen consumption in the tissue and the cardiac output have the greatest influence on the SpO2 drop and minimal SpO2 value during simulated desaturation. The rate of development of desaturation and its duration are most affected by the diffusion resistance of the alveolar-capillary membrane. The results of the sensitivity analysis will help to optimize the performance of the computer model of neonatal oxygen transport.

Nocturnal oxygen desaturation in the late third trimester of uncomplicated pregnancy for prediction of late-onset gestational hypertension.

This study aimed to determine whether 1-night screening of oxygen desaturation in women with uncomplicated pregnancy about 1 month before the due date is useful to predict late-onset gestational hypertension (GH) after 37 weeks of gestation. We recruited 102 women with uncomplicated pregnancy between 34 and 36 weeks of gestation. These women then completed the Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, and Berlin Questionnaire for obstructive sleep apnea, and recorded their oxygen saturation (SpO2 ) and physical acceleration profiles during nocturnal sleep for 1 night at home using a portable pulse oximeter and actigraph, respectively. Thereafter, their blood pressure was monitored weekly until delivery. Pulse oximetry data between 34 and 36 weeks of gestation revealed that three women had an oxygen desaturation index (ODI) ≥5.0 and seven had a minimum SpO2 < 90%. During follow-up until delivery, two women with an ODI ≥5.0 and a minimum SaO2 <90% developed GH at 37 weeks of gestation. Among clinical measures at recruitment, body mass index (BMI) and pulse oximetry measures appeared available for the prediction of GH. The positive predictive values (95% confidence intervals) of the criteria using these measures were 0.67 (0.26-0.67) for ODI ≥5.0, 0.29 (0.10-0.35) for minimum SpO2 <90%, and 0.07 (0.02-0.07) for BMI ≥25.0. For the prediction of late-onset GH after 37 weeks of gestation, pulse oximetry measures about 1 month before the due date are particularly useful because of their high positive predictive values.