Minimum SaO2 Research Articles

Pulmonary hypertension in obstructive sleep apnea hypopnea syndrome

BackgroundThere has been uncertainty until recently whether OSA, is sufficient to cause persistent daytime pulmonary hypertension and right ventricular dysfunction. ObjectivesThe aims of this study, were to investigate whether OSA by itself without any other cardiac or lung disease can lead to pulmonary hypertension, and to assess the effect of CPAP therapy on pulmonary artery pressure. Subjects and methodsThe study was performed on 54 OSA patients. All patients were subjected to thorough history taking including Epworth sleepiness scale and Berlin questionnaire, physical examinations, calculation of BMI, plain chest X-ray pulmonary function tests, polysomnography and echocardiography. Ten patients out of 24 patients of OSA with PH have been treated with CPAP for six months. ResultsPulmonary hypertension (PH) was present in (44.4%) of OSA patients. There were significantly higher PASP and mPAP in severe OSA patients versus non severe OSA patients. There were significant higher BMI, neck circumference, AHI and ODI in OSA patients with PH compared to OSA patients without PH. Awake SaO2 and minimum SaO2 were significantly lower in OSA patients with PH compared to OSA patients without PH. There were significant reduction in both mPAP and PASP after 6months of CPAP treatment (p=0.007, 0.005 respectively). ConclusionOSA is associated with pulmonary hypertension, improvement of pulmonary hypertension through controlling OSA by CPAP therapy signifies that OSA plays a crucial role in the pathogenesis of pulmonary hypertension. RecommendationsCPAP therapy should be advised to all OSA patients with pulmonary hypertension.

Assessment of left ventricular systolic dysfunction and its relationships with cardiovascular risk factors in patients with obstructive sleep apnea syndrome by two-dimensional speckle tracking imaging

Objective To investigate left ventricular (LV) systolic dysfunction of different left ventricular geometric patterns and its relationships with cardiovascular risk factors by two-dimensional speckle tracking imaging (2D-STI) in patients with obstructive sleep apnea syndrome (OSAS) with normal left ventricular ejection fraction (LVEF).Methods 95 patients with habitual snoring were diagnosed as OSAS by polysomnography with apnea hypopnea index(AHI)≥ 5/h.Blood pressure and general clinical characteristics were collected and echocardiography was done next morning.LV geometric patterns was categorized as normal geometry (NG),concentric remodeling (CR),eccentric hypertrophy (EH) and concentric hypertrophy (CH) on the basis of relative wall thickness (RWT)＞0.42 and LV mass index (LVMI)＞46.7 g/m27 (female) or 49.2 g/m2.7 (male).LVEF was calculated by bi-plane Simpson's rule.Global peak systolic circumferential strain (GCS),radial strain (GRS) and longitudinal strain (GLS) were measured by 2D-STI.Multivariate linear regression analysis was applied to analyse the relationships between 2D-STI parameters and cardiovascular risk factors.Results ① Of 95 OSAS patients,there were 41(43.1 ％) in NG,23 (24.2％) in CR,16 (16.8％) in EH and 15 (15.9％) in CH respectively.There was no significant difference in LVEF between groups (P ＞ 0.05).Male,age,heart rate,blood pressure,neck circumference,waist,hip circumference,smoking,TC,TG,HDL,LDL,fasting glucose,AHI,saturation of artery oxygen (SaO2) and oxygen desaturation index (ODI) did not differ between groups (P ＞0.05).②GLS was lower in patients with CH (P ＜0.05).GCS and GRS had no significant difference between groups (P ＞0.05).③In Pearson correlation analysis,GLS was correlated with AHI (r =0.326),LVMI (r =0.274),T90 (r =0.294),minimum SaO2 (r =-0.299),body mass index(BMI) (r =0.367).In multivariate linear regression analysis,AHI,LVMI,BMI were independent predictors of GLS (R2 =0.219,P ＜0.05).Conclusions ①LV longitudinal systolic dysfunction was damaged more severiously in patient of CH with OSAS.②Severity of OSAS,LV hypertrophy and obesity were associated with LV longitudinal systolic dysfunction in patient with OSAS. Key words: Echocardiography; Sleep apnea,obstructive; Ventricular function,left

Polysomnographic evaluation of propofol‐induced sleep in patients with respiratory sleep disorders and controls

The treatment for obstructive sleep apnea syndrome (OSAS) depends on correct localization of upper airway obstruction, exception made for continuous positive airway pressure (CPAP). Drug-induced sleep endoscopy (DISE) with propofol allows this evaluation, but the drug effects on sleep parameters are not yet well established. Our objective was to study by polysomnography (PSG) whether propofol would change sleep parameters by means of a prospective cross-sectional clinical study in a tertiary hospital. Thirty non-obese subjects (6 controls and 24 OSAS patients) underwent two daytime PSGs, one with DISE and the other without DISE. During DISE exam, propofol was administered intravenously in continuous infusion using a target-controlled infusion pump. The parameters evaluated were: presence of snoring, apnea-hypopnea index (AHI), oxyhemoglobin saturation (SaO2), and sleep macroarchitecture. Snoring was absent in all healthy subjects during DISE sleep with propofol, and present in all OSAS patients (100%). AHI and mean SaO2 showed no statistical difference between the two tests, with and without propofol. However, minimum SaO2 was significantly lower during propofol infusion (88.64 for without vs. 85.04 for with propofol; P < 0.01). Regarding sleep macroarchitecture, the tests with propofol significantly increased N3 sleep and totally extinguished REM sleep (P < 0.005). The results demonstrate that propofol significantly changes sleep macroarchitecture. However, the main respiratory parameters, AHI and mean SaO2 , remained unaffected. Thus, in order to determine the sites of obstruction, propofol DISE used with target-controlled infusion proved to be an effective drug for endoscopic evaluation of patients with OSAS.

Glucose Tolerance and Weight Loss in Obese Women with Obstructive Sleep Apnea

BackgroundThe association of obstructive sleep apnea (OSA) with glucose intolerance and the beneficial effect of lifestyle intervention have been poorly investigated in women particularly before menopausal status. The study explored 1) whether OSA is associated with impaired glucose homeostasis in obese non diabetic premenopausal and menopausal women and 2) the effects of a 3- month lifestyle intervention on glucose homeostasis in OSA women.Design and MethodsWe consecutively recruited 98 obese women (39 premenopausal) from those referred for a weight loss intervention. Ambulatory nocturnal polysomnography, body composition, oral glucose tolerance test, insulin sensitivity and β cell function were assessed before and after intervention.Results41% of premenopausal and 64% of menopausal women had OSA which was associated with worse glucose homeostasis before menopausal status. Mean and minimal nocturnal oxygen saturation (SaO2) was associated with neck/height ratio (NHR), independently of total and central obesity. Mean and minimal nocturnal SaO2 and NHR were correlated with insulin sensitivity and fasting glucose. In multivariate analyses, nocturnal mean SaO2 was negatively and independently correlated with fasting glucose (p<0.0001) and NHR with insulin sensitivity (p<0.0001). In OSA women, the intervention induced a 5% weight reduction and a significant increase in minimal nocturnal SaO2, insulin sensitivity and β cell function. Changes in fasting glucose and insulin sensitivity were associated with those in minimal nocturnal SaO2 (p<0.05) and not with weight loss.ConclusionsIn obese women, glucose homeostasis worsens due to nocturnal hypoxia and increased neck circumference through mechanisms partially independent of obesity. OSA is more clearly associated with glucose intolerance in premenopausal than in menopausal women. In OSA women, the improvement of nocturnal hypoxia induced by lifestyle modifications is associated with that of glucose homeostasis.

Predictive Risk Factors of Cardiorespiratory Abnormality for Upper Gastrointestinal Endoscopy in Tibet

To explore the predictive factors of cardiorespiratory abnormality in nonsedated patients at high altitude (HA) during upper gastrointestinal endoscopy (UGIE). The pulse and saturated oxygen (SaO2) levels of 993 patients undergoing nonsedated UGIE in Tibet were monitored. Bivariate correlation and logistic regression were used to identify predictive risk factors for hypoxemia. The basal and minimum SaO2 levels during UGIE of the Tibetan group were significantly higher than those of the non-Tibetan group. The minimum SaO2 and maximum pulse in the HA transient residents groups were significantly higher than those in the HA usual residents groups. The incidences of hypoxemia and severe hypoxemia in the Tibetan groups were significantly lower than those of the non-Tibetan groups. Bivariate correlation and logistic regression showed that race, age (≥ 40 years), residence time in HA (<10 years), and basal SaO2 (<89 %) were sufficiently effective to predict hypoxemia. High-risk hypoxemic patients whose residence time in HA was <2 years were more prone to severe hypoxemia. The combination of the four variables showed superior performance in hypoxemia prognosis (AUC-ROC, 0.941; sensitivity, 83.7 %; specificity, 92.5 %) and severe hypoxemia prognosis (AUC-ROC, 0.968; sensitivity, 90.3 %; specificity, 98.0 %). Race, age, residence time in HA, and basal SaO2 of patients in HA were predictive variables for hypoxemia during UGIE. Non-Tibetan patients with age ≥ 40 years, residence time in HA <10 years, and basal SaO2 <89 % were prone to hypoxemia. Among those groups, patients whose residence time was <2 years were at higher risk for severe hypoxemia.

The Interaction of Obstructive Sleep Apnea and Obesity on the Inflammatory Markers C-Reactive Protein and Interleukin-6: The Icelandic Sleep Apnea Cohort

To assess the relative roles and interaction of obstructive sleep apnea (OSA) severity and obesity on interleukin-6 (IL-6) and C-reactive protein (CRP) levels. Cross-sectional cohort. The Icelandic Sleep Apnea Cohort. 454 untreated OSA patients (380 males and 74 females), mean ± standard deviation age 54.4 ± 10.6 yr. N/A. Participants underwent a sleep study, abdominal magnetic resonance imaging to measure total abdominal and visceral fat volume, and had fasting morning IL-6 and CRP levels measured in serum. A significantly higher correlation was found for BMI than visceral fat volume with CRP and IL-6 levels. Oxygen desaturation index, hypoxia time, and minimum oxygen saturation (SaO₂) significantly correlated with IL-6 and CRP levels, but apnea-hypopnea index did not. When stratified by body mass index (BMI) category, OSA severity was associated with IL-6 levels in obese participants only (BMI > 30 kg/m²). A multiple linear regression model with interaction terms showed an independent association of OSA severity with IL-6 levels and an interaction between OSA severity and BMI, i.e., degree of obesity altered the relationship between OSA and IL-6 levels. An independent association of OSA severity with CRP levels was found for minimum SaO₂ only. A similar interaction of OSA severity and BMI on CRP levels was found for males and postmenopausal women. OSA severity is an independent predictor of levels of IL-6 and CRP but interacts with obesity such that this association is found only in obese patients.

Arrhythmia and sleep-disordered breathing in patients undergoing cardiac surgery

BackgroundRecently, the role of sleep-disordered breathing (SDB) in cardiovascular disease has attracted attention. In this study, we investigated the influence of SDB on postoperative arrhythmias after cardiac surgery. Methods and resultsIn 89 patients undergoing cardiac surgery, postoperative portable monitoring for SDB and Holter electrocardiography were performed. The primary end-points were the apnea–hypopnea index (AHI) and occurrence of arrhythmia. The secondary end-points were: (1) patient background factors; (2) average heart rate; (3) maximum heart rate (total, daytime, and nighttime); (4) minimum heart rate (total, daytime, and nighttime); (5) minimum SaO2 during sleep; and (6) an independent predictor for arrhythmia.Twenty-six patients (29.2%) had an AHI≥15 and they were classified into the SDB group, while patients with an AHI<15 formed the non-SDB group (70.8%). Although there was no significant difference in atrial fibrillation, frequent nocturnal premature ventricular contractions were significantly more common in the SDB group (19.2%) than the non-SDB group (3.2%) (p=0.01). Maximum daytime and nighttime heart rates were also significantly higher in the SDB group. AHI was a significant predictor for frequent nocturnal premature ventricular contractions. ConclusionsThis study showed that SDB is common among patients undergoing cardiac surgery, and that SDB might be closely associated with arrhythmia in these patients.

Obstructive sleep apnoea in adults: body postures and weight changes interactions

The aim of this work was to study the relationship between changes of body posture dominance and changes of body weight overtime in adults with obstructive sleep apnoea. The participants were 112 non-treated adults with obstructive sleep apnoea who underwent two polysomnographic evaluations at our Sleep Disorders Unit during an average of 6.2years interval. Positional patients - having most of their breathing abnormalities in the supine posture and who became non-positional patients - had a significant gain in weight and a significant increase in apnoea-hypopnoea index, mainly in lateral apnoea-hypopnoea index. On the contrary, non-positional patients who became positional patients had a significant decrease in weight (but less than the increase in weight of positional patients who became non-positional patients) and showed a significant improvement in apnoea-hypopnoea index, again mainly in lateral apnoea-hypopnoea index. These non-positional patients who became positional patients initially had a less severe disease, as judged by apnoea-hypopnoea index, lateral apnoea-hypopnoea index and minimum SaO(2) during non-rapid eye movement sleep, and were less obese than non-positional patients who remained non-positional patients. The later were the patients who showed initially the worst disease and were more obese than the rest of the patients, and their condition did not change significantly over time. Non-positional patients who converted to positional patients showed a decrease in body weight and improvement of obstructive sleep apnoea, while positional patients who converted to non-positional patients showed an increase in body weight and worsening of obstructive sleep apnoea. It appears that weight changes have a modulatory effect on positional dominance, and lateral apnoea-hypopnoea index appears to be a sensitive parameter of these changes.

Pediatric Periodic Limb Movement Disorder: Sleep Symptom and Polysomnographic Correlates Compared to Obstructive Sleep Apnea

Although periodic limb movements in sleep (PLMS) have been described in multiple pediatric publications, periodic limb movement disorder (PLMD) has not. The aims of this study were to describe the prevalence, sleep-related correlates, and polysomnographic correlates of PLMD in a large pediatric case series, and compare these to pediatric obstructive sleep apnea (OSA). All PLMD cases (defined by International Classification of Sleep Disorders, 2nd edition criteria + respiratory disturbance index [RDI] < 3) and OSA cases (defined by RDI ≥ 3 + PLMS < 5), from a single pediatric sleep practice, over a 2-year time span, were included. Chart, questionnaire, and polysomnographic data were compiled. Of 468 referred children, 66 PLMD cases were identified (14%). The PLMD cases, mean age 8.1 years (range 1-17), were clinically characterized by frequent sleep onset and maintenance problems, difficulty awakening, restless sleep, leg pain/discomfort at night, and parasomnias. Compared to 90 OSA children, those with PLMD had a history of significantly more sleep onset and maintenance problems, leg pain/discomfort at night, parasomnias, getting out of bed at night, and family history of restless legs syndrome. Polysomnographically, PLMD cases had more awakenings, stage 1 sleep, stage shifts, and spontaneous arousals. These data indicate that pediatric PLMD has important clinical and polysomnographic correlates. In addition, PLMD has many characteristics that are different from pediatric OSA, suggesting that PLMD is a distinct pediatric sleep disorder, of which clinicians should be aware.

Effect of upper airway surgery on heart rate variability in patients with obstructive sleep apnoea syndrome

To determine whether surgery influences cardiovascular autonomic modulation in obstructive sleep apnoea syndrome (OSAS), the present study was performed to evaluate the effect of upper airway (UA) surgery on heart rate variability (HRV) using frequency domain analysis for patient groups who have had either successful or unsuccessful surgery. We compared body mass index (BMI), polysomnographic [apnoea index (AI), apnoea-hypopnoea index (AHI), minimum SaO(2)] and HRV [very low frequency (VLF) power, low frequency (LF) power, high frequency (HF) power, HF/LF ratio, LFnu = LF/(LF + HF), HFnu = HF/(LF + HF)] parameters between the unsuccessful (n = 14) and successful (n = 22) surgical groups before and after UA surgery. Significant changes were observed for the successful patient group with respect to mean AI (from 29.1 ± 21.3 to 2.0 ± 3.2 events h(-1), P < 0.001), AHI (from 38.6 ± 20.0 to 5.6 ± 5.1 events h(-1), P < 0.001), minimum SaO(2) (from 73.3 ± 12.7 to 86.3 ± 6.5%, P < 0.001), VLF power (from 25599 ± 12906 to 20014 ± 9839 ms(2), P = 0.013), LF power (from 17293 ± 7278 to 14155 ± 4980 ms(2), P = 0.016), LFnu (from 0.700 ± 0.104 to 0.646 ± 0.128, P = 0.031) and HFnu (from 0.300 ± 0.104 to 0.354 ± 0.128, P = 0.031); however, mean BMI, HF power and LF/HF ratio did not change significantly after UA surgery. No significant changes were observed in the unsuccessful surgical group. Successful UA surgery may improve cardiac sympathetic and parasympathetic modulation in patients with OSAS.

Effectiveness of Nasal Surgery Alone on Sleep Quality, Architecture, Position, and Sleep-Disordered Breathing in Obstructive Sleep Apnea Syndrome with Nasal Obstruction

The goal of this study was to evaluate the effect of nasal surgery alone on sleep quality, architecture, position, and sleep-disordered breathing (SDB) (including obstructive apnea and snoring) in adult patients with obstructive sleep apnea syndrome (OSAS) and nasal obstruction. A total of 22 consecutive male patients (mean age, 41.3 ± 10.9 years) with OSAS and nasal obstruction, who underwent nasal surgery alone, were enrolled in the study. We compared polysomnographic data related with sleep quality (sleep efficiency [SE] and arousal index [ArI]), sleep architecture (stages N [nonrapid eye movement], 1, 2, and 3, and R [rapid eye movement]), the distribution of sleep positions, and SDB (apnea-hypopnea index [AHI], apnea index [AI], minimum arterial oxygen saturation [SaO(2)], and snoring) before and after nasal surgery. SE (from 86.6 ± 6.3% to 89.7 ± 7.1%; p = 0.039), stage R (from 15.3 ± 4.8% to 18.6 ± 5.4%; p = 0.016) and snoring (from 32.2 ± 16.4% to 25.8 ± 18.6%; p = 0.045) significantly changed after nasal surgery. However, there were no significant changes in ArI, other sleep stages, the proportion of sleep time spent in the supine position, AHI, AI, and minimum SaO(2) after nasal surgery. Nasal surgery alone was partially effective in improving sleep quality, architecture, and snoring, but it had no effect on the change of the distribution of sleep positions and obstructive apnea in patients with OSAS and nasal obstruction.

Polysomnographic Evaluation of Drug Induced Sleep Endoscopy (DISE)

Objective: DISE is increasingly being used to localize the obstructive site in OSAS patients. The objective of this study is to determine if propofol changes sleep parameters in polysomnography. Method: Thirty subjects (6 controls/24 with OSAS) underwent 2 diurnal polysomnographies, with/without the use of propofol, controlled by target-controlled infusion pump (Diprifusor). The examinations were compared regarding the presence of snoring, AHI, oxygen desaturation, and sleep architecture. Endoscopies with the patients sleeping and awake were also compared. Results: The use of propofol did not induce snoring in the control subjects, whereas 100% of the OSAS patients snored. Propofol increased N3 sleep and abolished totally REM sleep (P2 did not differ significantly between the 2 examinations ( P &gt; .05). The minimum SaO2 were significantly reduced during propofol sedation. Conclusion: Propofol changed the sleep architecture, but not the main respiratory parameters in OSAS. DISE was shown to be safe and more reliable to determine the sites of obstruction, supporting the view that this examinations is promising for the management of this disease.

Stepped approach for prediction of syndrome Z in patients attending sleep clinic: a north Indian hospital-based study

Syndrome Z is the occurrence of metabolic syndrome (MS) with obstructive sleep apnea. Knowledge of its risk factors is useful to screen patients requiring further evaluation for syndrome Z. Consecutive patients referred from sleep clinic undergoing polysomnography in the Sleep Laboratory of AIIMS Hospital, New Delhi were screened between June 2008 and May 2010, and 227 patients were recruited. Anthropometry, body composition analysis, blood pressure, fasting blood sugar, and lipid profile were measured. MS was defined using the National Cholesterol Education Program (adult treatment panel III) criteria, with Asian cutoff values for abdominal obesity. Prevalence of MS and syndrome Z was 74% and 65%, respectively. Age, percent body fat, excessive daytime sleepiness (EDS), and ΔSaO(2) (defined as difference between baseline and minimum SaO(2) during polysomnography) were independently associated with syndrome Z. Using a cutoff of 15% for level of desaturation, the stepped predictive score using these risk factors had sensitivity, specificity, positive predictive value, and negative predictive value of 75%, 73%, 84%, and 61%, respectively for the diagnosis of syndrome Z. It correctly characterized presence of syndrome Z 75% of the time and obviated need for detailed evaluation in 42% of the screened subjects. A large proportion of patients presenting to sleep clinics have MS and syndrome Z. Age, percent body fat, EDS, and ΔSaO(2) are independent risk factors for syndrome Z. A stepped predictive score using these parameters is cost-effective and useful in diagnosing syndrome Z in resource-limited settings.

Polysomnographic characteristics of daytime sleepiness in obstructive sleep apnea syndrome

The study is intended to explore the nocturnal sleep determinants for excessive daytime sleepiness (EDS) in patients with obstructive sleep apnea syndrome (OSAS). Consecutive patients (n = 182) who had an apnea/hypopnea index (AHI) greater than 5 times per hour were used in this study. EDS (n = 32) was considered present whenever the Epworth sleepiness scale (ESS) score was >10 and the multiple sleep latency test (MSLT) score was <5min. Absence of EDS (no EDS, n = 48) was determined in patients with an ESS score of <10 and a MSLT score of >10min. Compared to no EDS patients, EDS patients exhibited (1) greater AHI and time length of SaO(2) <95%, lower nocturnal SaO(2) during separate rapid eye movement (REM) and NREM periods, and lower total mean and minimum SaO(2) during total recording period; (2) shortened latency to sleep and to REM sleep, and increased total sleep time and sleep efficiency; and (3) increases in the brief arousal index and duration of sleep stage 1. In addition, stepwise logistic regression analysis showed that the arousal index, the time length of SaO(2) <95%, and the latency to REM were independent predictors of EDS. The results suggest that EDS in OSAS patients are characterized by the following aspects of nocturnal sleep: (1) severe sleep apnea/hypopnea and hypoxemia, (2) fragmented sleep, (3) low quality of sleep, and (4) high pressure of sleep drive.

El test de seis minutos de marcha como predictor de mortalidad en lista de espera para trasplante pulmonar

Introduction Lung transplant waiting list mortality makes it necessary to prioritize the criteria. Objective To analyze the role of the six-minute walking test (6MWT) as a predictor of waiting list mortality. Patients and methods We conducted a prospective study of patients considered for lung transplantation between 1998 and 2007. The variables analyzed were: distance walked in metros and minimum oxygen saturation (SaO 2) during 6MWT, age, gender, underlying disease and waiting list mortality. Results A total of 453 patients were included, 64.2% males, mean age 49.7 ± 14.8 years. Mean distance walked was 322 ± 93 m and minimum SaO 2 84.1% ± 7.6%. Eighteen patients on the waiting list died (4%) (95%CI, 2.2-5.8). Those patients in the survival group walked significantly farther than those who had died (321 ± 90 vs. 262 ± 115 m; P=.001). Similarly, 6.5% of patients with SaO 2 <85% died compared to 1% with higher values ( P=.006). Cystic fibrosis patients had higher mortality than other diagnosis (10.4% vs. 3.2; P=.043). Multivariate analysis confirmed the independent relation between mortality and the three risk factors. The odds ratio (OR) for cystic fibrosis waiting list mortality was 5.6 (95%CI, 1.7-18.9); for SaO 2 <85%, 5.7 (95%CI, 1.3-25.1), and 7.3 (95%CI, 2.5-21) for less than 200 m walk. Conclusions Cystic fibrosis patients have a higher risk of waiting list mortality. Patients who walk less than 200 m and/or have a SaO 2 <85% during the 6MWT have a higher risk of waiting list mortality so that their prioritization should be considered.

Relationship between excessive daytime sleepiness and oxygen saturation in obstructive sleep apnea-hypopnea syndrome

To investigate polysomnographic determinants of excessive daytime sleepiness (EDS) and potential relationship in Chinese patients with obstructive sleep apnea-hypopnea syndrome (OSAS). A total of 410 patients with obstructive sleep apnea-hypopnea syndrome were analyzed retrospectively who were obtained in Sleep medicine center of West China hospital from January to April in 2010. All of the patients with an apnea-hypopnea index (AHI) greater than 5 h(-1) were evaluated using the Epworth Sleepiness Scale (ESS) and sleep disorders questionnaire. The patients who ESS score was more than 10 were defined as EDS; otherwise, the other was considered to without EDS. A total of 176 patients with EDS (ESS: 15 ± 3) and 234 without EDS (ESS: 6 ± 3) were studied. Patients with EDS were slightly higher BMI (28 ± 4 vs 26 ± 4) and shorter REM sleep latency (99 ± 65 vs 125 ± 81) than patients without EDS. Furthermore, there were significant difference in awake SaO2, AHI, minimum SaO2, oxygen desaturation index and arousal index between EDS group were No-EDS group (P < 0.001). There was a significant difference in waking SaO2 of severe OSAS between both groups. Long-term chronic hypoxia already exists in severe OSAS patients with prominent sleepiness. Waking SaO2 may play a role as a predictor in evaluation and diagnosis in patients with OSAS.

Severe nocturnal cardiac arrhythmias caused by sleep apnea-induced hypoxemia in males

Nocturnal cardiac arrhythmias (NCA) were analyzed in patients with sleep apnea/hypopnea syndrome (SAHS) and controls. Occurrence and severity of NCA were compared in 33 SAHS patients and 16 control subjects, matched for cardiovascular risk factors. Continuous overnight polysomnography provided ECG, respiratory and sleep parameters for a comparative analysis. Various types and severity of NCA were detected already in moderate SAHS (apnea/hypopnea index = 26 ± 15.6/h), reflecting the respiratory and atherosclerotic changes. Moderately severe arrhythmias, represented with benign and 2 complex types were caused by hypoxemia characterized by AHI, minimal SaO2, and lower values after desaturation. Three-time higher prevalence of complex arrhythmias in SAHS patients was not significantly different by usual statistical comparison, likely due to a low number of controls and a joint occurrence of various types and complex severity of arrhythmias in some patients. Therefore, a complex assessment of different types and varying severity of arrhythmias would require a scale specifically constructed for their evaluation.

Study on hypoxemia during sleep in patients with chronic obstructive pulmonary disease

To investigate the influence of hypoxemia during sleep on elements of polysomnography (PSG) in patients with chronic obstructive pulmonary disease (COPD) and the correlation of sleep hypoxemia and arterial blood gases, pulmonary function in daytime. Two hundred and four moderate to very severe stable COPD patients with an age range of 40-75 years [mean age was (70.41+/-7.84) years ] were admitted. All patients underwent overnight PSG, and percentage of the time with oxygen saturation below 0.90 and total sleep time (T90)>or=5% was taken as nocturnal oxygen desaturation (NOD), and if not, they were non-NOD. Arterial blood gases, lung function and PSG examinations were performed in all patients. Ninety-five patients (46.57%) had NOD were enrolled. Compared with patients of non-NOD, both daytime oxygen saturation (SaO2, 0.90+/-0.04 vs. 0.94+/-0.01) and nocturnal mean SaO2 (MSaO2, 0.83+/-0.08 vs. 0.93+/-0.02) in NOD were lower significantly (both P<0.01). Sleep-related elements such as awake period (minutes: 97.86+/-41.74 vs. 76.13+/-55.15), awake frequency (times: 31.50+/-15.69 vs. 23.23+/-19.81), mean heart rate (beat per min: 80.80+/-12.80 vs. 66.21+/-6.53), sleep components [(S1+S2)%: (74.36+/-16.52)% vs. (67.55+/-12.62)%, (S3+S4)%: (12.99+/-12.18)% vs. (19.35+/-12.71)%] in NOD were significantly different from non-NOD (all P<0.01). The levels of arterial partial pressure of carbon dioxide (PaCO2), arterial partial pressure of oxygen (PaO2), percentage of forced expiratory volume in one second (FEV1) and anticipate value, percentage of forced vital capacity (FVC) and anticipate value, percentage of FEV1/FVC and anticipate value in daytime were respectively correlated with the T90, MSaO2 and minimum SaO2 (miniSaO2) in sleep. Among these measurements, PaCO2 was best correlated with sleep hypoxemia (r1=0.767, r2=-0.758, r3=-0.689, all P<0.01). Sleep hypoxemia existed generally in patients with moderate to very severe stable COPD. There was significant difference in nocturnal SaO2, daytime SaO2 and sleep-related elements between NOD and non-NOD. The measurements in daytime are correlated with sleep hypoxemia, and some of them may predict sleep hypoxemia.

Propofol-induced sleep: Polysomnographic evaluation of patients with obstructive sleep apnea and controls

Objective The localization of upper airway obstruction in patients with obstructive sleep apnea (OSA) may optimize treatment. Nasoendoscopy during propofol sedation allows such an evaluation, but the effect of this drug on respiratory patterns and muscle relaxation is unknown. The objective of the present study was to determine through polysomnography whether propofol would change sleep parameters. Study Design Prospective study of subjects submitted to polysomnography under sedation with propofol. Setting Tertiary referral center. Subjects and Methods Fifteen non-obese subjects (4 controls/11 OSA patients) were submitted to two diurnal polysomnograms (90-120 minutes of sleep), with and without the use of propofol. The parameters presence of snoring, apnea-hypopnea index (AHI), oxygen desaturation, and sleep architecture were compared. Results The use of propofol did not induce snoring in the control subjects, whereas 100 percent of the OSA patients snored. AHI and mean oxygen saturation (SaO 2) did not differ significantly between examinations with and without sedation. However, minimum SaO 2 differed significantly ( P < 0.05) with sedation, being lower during propofol sedation. Propofol also significantly changed the sleep architecture, with a significant increase in N3 sleep ( P < 0.005) and total abolishment of rapid eye movement sleep ( P < 0.0005) during propofol sedation. Conclusions These preliminary results allow us to infer that sedation with propofol changes sleep architecture but permits respiratory evaluation, because the main respiratory parameters evaluated in OSA are maintained. These preliminary results support the view that nasoendoscopy under propofol sedation is a promising examination for management of this disease.

Optimal continuous positive airway pressure level in korean patients with obstructive sleep apnea syndrome.

ObjectivesThe aim of this study was to investigate optimal continuous positive airway pressure (CPAP) level, to examine the factors affecting optimal CPAP level, and to develop a predictive equation for optimal CPAP level in Korean patients with obstructive sleep apnea syndrome (OSAS).MethodsA total of 202 patients with OSAS who underwent successful manual titration for CPAP treatment were included in this study. Correlations between the optimal CPAP level and baseline data including anthropometric and polysomnographic variables were analyzed. A predictive equation for optimal CPAP level was developed based on anthropometric and polysomonographic data.ResultsThe mean optimal CPAP level in 202 patients with OSAS was 7.8±2.3 cm H2O. The mean optimal CPAP level in the mild, moderate, and severe OSAS groups was 6.0±1.3, 7.4±1.9, and 9.1±2.1 cm H2O, respectively. The apneahypopnea index (AHI) (r=0.595, P<0.001), arousal index (r=0.542, P<0.001), minimal SaO2 (r=-0.502, P<0.001), body mass index (BMI) (r=0.494, P<0.001), neck circumference (r=0.265, P<0.001), and age (r=-0.164, P=0.019) were significantly correlated with optimal CPAP level. The best predictive equation according to stepwise multiple linear regression analysis was: Optimal CPAP level (cm H2O)=0.681+(0.205×BMI)+(0.040×AHI). Forty-two percent of the variance in the optimal CPAP level was explained by this equation (R2=0.42, P<0.001).ConclusionA predictive equation for optimal CPAP level in Korean patients with OSAS was developed using AHI and BMI, which can be easily measured during the diagnostic process.