Respiratory and polysomnographic values in 3- to 5-year-old normal children at higher altitude.
ABSTRACT: To determine polysomnographic parameter differences in children living at higher altitude to children living near sea level.Prospective study of non-snoring, normal children recruited from various communities around Denver, CO. In-lab, overnight polysomnograms were performed at a tertiary care children's hospital. All children required residence for greater than one year at an elevation around 1,600 meters.45 children (62% female), aged 3-5 years, 88.9% non-Hispanic white with average BMI percentile for age of 47.8% ± 30.7%.Standard sleep indices were obtained and compared to previously published normative values in a similar population living near sea level (SLG). In the altitude group (AG), the apnea-hypopnea index was 1.8 ± 1.2 and the central apnea-hypopnea index was 1.7 ± 1.1, as compared to 0.9 ± 0.8 and 0.8 ± 0.7, respectively, (P ? 0.005) in SLG. Mean end-tidal CO2 level in AG was 42.3 ± 3.0 mm Hg and 40.6 ± 4.6 mm Hg in SLG (P = 0.049). The ? 4% desaturation index was 3.9 ± 2.0 in AG compared to 0.3 ± 0.4 in SLG (P < 0.001). Mean periodic limb movement in series index was 10.1 ± 12.3 in AG and 3.6 ± 5.4 in SLG (P = 0.001).Comparison of altitude and sea level sleep studies in healthy children reveals significant differences in central apnea, apneahypopnea, desaturation, and periodic limb movement in series indices. Clinical providers should be aware of these differences when interpreting sleep studies and incorporate altitude-adjusted normative values in therapeutic-decision making algorithms.
Project description:Sleep-disordered breathing (SDB) is prevalent among children and is associated with adverse health outcomes. Worldwide, approximately 250 million individuals reside at altitudes higher than 2000 meters above sea level (masl). The effect of chronic high-altitude exposure on children with SDB is unknown. This study aims to determine the impact of altitude on sleep study outcomes in children with SDB dwelling at high altitude.A single-center crossover study was performed to compare results of high-altitude home polysomnography (H-PSG) with lower altitude laboratory polysomnography (L-PSG) in school-age children dwelling at high altitude with symptoms consistent with SDB. The primary outcome was apnea-hypopnea index (AHI), with secondary outcomes including obstructive AHI; central AHI; and measures of oxygenation, sleep quality, and pulse rate.Twelve participants were enrolled, with 10 included in the final analysis. Median altitude was 1644 masl on L-PSG and 2531 masl on H-PSG. Median AHI was 2.40 on L-PSG and 10.95 on H-PSG. Both obstructive and central respiratory events accounted for the difference in AHI. Oxygenation and sleep fragmentation were worse and pulse rate higher on H-PSG compared to L-PSG.These findings reveal a clinically substantial impact of altitude on respiratory, sleep, and cardiovascular outcomes in children with SDB who dwell at high altitude. Within this population, L-PSG underestimates obstructive sleep apnea and central sleep apnea compared to H-PSG. Given the shortage of high-altitude pediatric sleep laboratories, these results suggest a role for home sleep apnea testing for children residing at high altitude.
Project description:Background Although sleep characteristics have been linked to cardiovascular disease and cardiovascular risk factors, the association between sleep characteristics measured by polysomnography and cardiovascular health ( CVH ) remains unknown. Methods and Results In a population-based sample (n=1826), sleep characteristics were assessed by both sleep questionnaires and polysomnography. Global, behavioral, and biological CVH were defined according to the American Heart Association. Multinomial logistic regressions were performed to estimate relative risk ratios and 95% CI . Strong dose-response associations were found between all oxygen saturation-related variables (oxygen desaturation index, mean oxygen saturation, and percentage of total sleep time spent under 90% oxygen saturation) and obstructive sleep apnea (severity categories and apnea/hypopnea index) and global, behavioral, and biological CVH . Mean oxygen saturation had the strongest positive association (relative risk ratios 1.31 [ CI 1.22-1.41]; 1.78 [ CI 1.55-2.04] for intermediate relative to ideal CVH ), and oxygen desaturation index had the strongest negative association (relative risk ratios 0.71 [ CI 0.65-0.78]; 0.45 [ CI 0.34-0.58] for intermediate relative to ideal CVH ) with global CVH , and these associations were also the most robust in sensitivity analyses. The impacts of sleep architecture and sleep fragmentation were less consistent. Conclusions Mean oxygen saturation, oxygen desaturation index, and apnea/hypopnea index were associated with CVH . Conversely, most variables related to sleep architecture and sleep fragmentation were not consistently related to CVH . Sleep-disordered breathing and the associated oxygen (de)saturation were associated with CVH more strongly than with sleep fragmentation.
Project description:BACKGROUND:Obstructive sleep apnea syndrome (OSAS) is a common disease. The objective of this research was to determine the effectiveness of a graduated walking program in reducing the apnea-hypopnea index number in patients with obstructive sleep apnea syndrome (OSAS). METHODS:A randomized controlled clinical trial with a two-arm parallel in three tertiary hospitals was carried out with seventy sedentary patients with moderate to severe OSAS. Twenty-nine subjects in each arm were analyzed by protocol. The control group received usual care, while usual care and an exercise program based on progressive walks without direct supervision for 6 months were offered to the intervention group. RESULTS:The apnea-hypopnea index decreased by six points in the intervention group, and improvements in oxygen desaturation index, total cholesterol, and Low-Density Lipoprotein of Cholesterol (LDL-c) were observed. A higher decrease in sleep apnea-hypopnea index (45 ± 20.6 vs. 34 ± 26.3/h; p = 0.002) was found in patients with severe vs. moderate OSAS, as well as in oxygen desaturation index from baseline values (43.3 vs. 34.3/h; p = 0.046). Besides, High-Density Lipoprotein of Cholesterol (HDL-c) values showed a higher increase in the intervention group (45.3 vs. 49.5 mg/dL; p = 0.009) and also, a higher decrease in LDL-c was found in this group (141.2 vs. 127.5 mg/dL; p = 0.038). CONCLUSION:A home physical exercise program is a useful and viable therapeutic measure for the management of OSAS.
Project description:There is uncertainty over which characteristics increase obstructive sleep apnea syndrome (OSAS) severity in children. In candidates for adenotonsillectomy (AT), we evaluated the relationship of OSAS severity and age, sex, race, body mass index (BMI), environmental tobacco smoke (ETS), prematurity, socioeconomic variables, and comorbidities.Cross-sectional screening and baseline data were analyzed from the Childhood Adenotonsillectomy Trial, a randomized, controlled, multicenter study evaluating AT versus medical management. Regression analysis assessed the relationship between the apnea hypopnea index (AHI) and risk factors obtained by direct measurement or questionnaire.Clinical referral setting.Children, ages 5 to 9.9 y with OSAS.Of the 1,244 children undergoing screening polysomnography, 464 (37%) were eligible (2 ? AHI < 30 or 1 ? obstructive apnea index [OAI] < 20 and without severe oxygen desaturation) and randomized; 129 (10%) were eligible but were not randomized; 608 (49%) had AHI/OAI levels below entry criteria; and 43 (3%) had levels of OSAS that exceeded entry criteria. Among the randomized children, univariate analyses showed significant associations of AHI with race, BMI z score, environmental tobacco smoke (ETS), family income, and referral source, but not with other variables. After adjusting for potential confounders, African American race (P = 0.003) and ETS (P = 0.026) were each associated with an approximately 20% increase in AHI. After adjusting for these factors, obesity and other factors were not significant.Apnea hypopnea index level was significantly associated with race and environmental tobacco smoke, highlighting the potential effect of environmental factors, and possibly genetic factors, on pediatric obstructive sleep apnea syndrome severity. Efforts to reduce environmental tobacco smoke exposure may help reduce obstructive sleep apnea syndrome severity.Clinicaltrials.gov (#NCT00560859).
Project description:Pham, Luu V., Christopher Meinzen, Rafael S. Arias, Noah G. Schwartz, Adi Rattner, Catherine H. Miele, Philip L. Smith, Hartmut Schneider, J. Jaime Miranda, Robert H. Gilman, Vsevolod Y. Polotsky, William Checkley, and Alan R. Schwartz. Cross-sectional comparison of sleep-disordered breathing in native Peruvian highlanders and lowlanders. High Alt Med Biol. 18:11-19, 2017.Altitude can accentuate sleep disordered breathing (SDB), which has been linked to cardiovascular and metabolic diseases. SDB in highlanders has not been characterized in large controlled studies. The purpose of this study was to compare SDB prevalence and severity in highlanders and lowlanders.170 age-, body-mass-index- (BMI), and sex-matched pairs (age 58.2?±?12.4 years, BMI 27.2?±?3.5?kg/m2, and 86 men and 84 women) of the CRONICAS Cohort Study were recruited at a sea-level (Lima) and a high-altitude (Puno, 3825?m) setting in Peru. Participants underwent simultaneous nocturnal polygraphy and actigraphy to characterize breathing patterns, movement arousals, and sleep/wake state. We compared SDB prevalence, type, and severity between highlanders and lowlanders as measured by apnea-hypopnea index (AHI) and pulse oximetry (SPO2) during sleep.Sleep apnea prevalence was greater in highlanders than in lowlanders (77% vs. 54%, p?<?0.001). Compared with lowlanders, highlanders had twofold elevations in AHI due to increases in central rather than obstructive apneas. In highlanders compared with lowlanders, SPO2 was lower during wakefulness and decreased further during sleep (p?<?0.001). Hypoxemia during wakefulness predicted sleep apnea in highlanders, and it appears to mediate the effects of altitude on sleep apnea prevalence. Surprisingly, hypoxemia was also quite prevalent in lowlanders, and it was also associated with increased odds of sleep apnea.High altitude and hypoxemia at both high and low altitude were associated with increased SDB prevalence and severity. Our findings suggest that a large proportion of highlanders remain at risk for SDB sequelae.
Project description:Rapid eye movement-predominant obstructive sleep apnea has been shown to be independently associated with hypertension. This study aimed to non-invasively measure blood pressure during the rapid eye movement (REM) and non-rapid eye movement (NREM) obstructive events and the post-obstructive event period. Thirty-two consecutive continuous positive airway pressure-naïve obstructive sleep apnea patients (men, 50%) aged 50.2?±?12 years underwent overnight polysomnography. Blood pressure was assessed indirectly using a validated method based on the pulse transit time and pulse wave velocity during the NREM and REM obstructive events (both apneas and hypopneas) and the post-obstructive event period. Among the recruited patients, 10 (31.3%) had hypertension. Mean apnea-hypopnea index was 40.1?±?27.6 events/hr. Apnea-hypopnea indexes were 38.3?±?30.6 and 51.9?±?28.3 events/hr for NREM and REM sleep, respectively. No differences were detected in obstructive respiratory event duration or degree of desaturation between REM and NREM sleep. Additionally, no difference in blood pressure (systolic and diastolic) was detected between REM and NREM sleep during obstructive events and post-obstructive event period. Simple linear regression identified history of hypertension as a predictor of increased systolic blood pressure during obstructive events and post-obstructive event period in both rapid eye movement and non-rapid eye movement sleep. Oxygen desaturation index was also a predictor of increased systolic blood pressure during obstructive events and post-obstructive event period in REM sleep. When obstructive event duration and the degree of desaturation were comparable, no difference in blood pressure was found between REM and NREM sleep during obstructive events and post-obstructive event period.
Project description:Although sleep apnea-hypopnea syndrome (SAHS) is highly prevalent in patients with type 2 diabetes (T2D), it is unknown whether or not subjects with and without T2D share the same sleep breathing pattern.A cross-sectional study in patients with SAHS according to the presence (n = 132) or not (n = 264) of T2D. Both groups were matched by age, gender, BMI, and waist and neck circumferences. A subgroup of 125 subjects was also matched by AHI. The exclusion criteria included chronic respiratory disease, alcohol abuse, use of sedatives, and heart failure. A higher apnea hypopnea index (AHI) was observed in T2D patients [32.2 (10.2-114.0) vs. 25.6 (10.2-123.4) events/hours; p = 0.002). When sleep events were evaluated separately, patients with T2D showed a significant increase in apnea events [8.4 (0.1-87.7) vs. 6.3 (0.0-105.6) e/h; p = 0.044), as well as a two-fold increase in the percentage of time spent with oxygen saturation <90% [15.7 (0.0-97.0) vs. 7.9 (0.0-95.6) %; <0.001)], higher rates of oxygen desaturation events, and also higher daily sleepiness [7.0 (0.0-21.0) vs. 5.0 (0.0-21.0); p = 0.006)] than subjects without T2D. Significant positive correlations between fasting plasma glucose and AHI, the apnea events, and CT90 were observed. Finally, multiple linear regression analyses showed that T2D was independently associated with AHI (R2 = 0.217), the apnea index (R2 = 0.194), CT90 (R2 = 0.222), and desaturation events.T2D patients present a different pattern of sleep breathing than subject without diabetes. The most important differences are the severity of hypoxemia and the number of apneas whereas the incidence of hypopnea episodes is similar.
Project description:Previous studies have observed an altitude-dependent increase in central apneas and a shift towards lighter sleep at altitudes >4000 m. Whether altitude-dependent changes in the sleep EEG are also prevalent at moderate altitudes of 1600 m and 2600 m remains largely unknown. Furthermore, the relationship between sleep EEG variables and central apneas and oxygen saturation are of great interest to understand the impact of hypoxia at moderate altitude on sleep.Fourty-four healthy men (mean age 25.0 ± 5.5 years) underwent polysomnographic recordings during a baseline night at 490 m and four consecutive nights at 1630 m and 2590 m (two nights each) in a randomized cross-over design.Comparison of sleep EEG power density spectra of frontal (F3A2) and central (C3A2) derivations at altitudes compared to baseline revealed that slow-wave activity (SWA, 0.8-4.6 Hz) in non-REM sleep was reduced in an altitude-dependent manner (~4% at 1630 m and 15% at 2590 m), while theta activity (4.6-8 Hz) was reduced only at the highest altitude (10% at 2590 m). In addition, spindle peak height and frequency showed a modest increase in the second night at 2590 m. SWA and theta activity were also reduced in REM sleep. Correlations between spectral power and central apnea/hypopnea index (AHI), oxygen desaturation index (ODI), and oxygen saturation revealed that distinct frequency bands were correlated with oxygen saturation (6.4-8 Hz and 13-14.4 Hz) and breathing variables (AHI, ODI; 0.8-4.6 Hz).The correlation between SWA and AHI/ODI suggests that respiratory disturbances contribute to the reduction in SWA at altitude. Since SWA is a marker of sleep homeostasis, this might be indicative of an inability to efficiently dissipate sleep pressure.
Project description:To assess the prevalence of obstructive sleep apnea in Saudi children with sickle cell disease at a tertiary hospital in Kingdom of Saudi Arabia (KSA) using nocturnal polysomnography. Methods: A prospective cross-section study was conducted between 2012 and 2016 in 65 children aged between 2-14 years at Prince Sultan Military Medical City, Riyadh, KSA with sickle cell disease. Patients answered a pediatric sleep questionnaire with the help of an accompanying caregiver and underwent polysomnography in the same night. Results: The final sample included 65 children. Median age was 8.1 years. There were 32 boys (49.2%) and 33 girls (50.8%). Mean hemoglobin was 8.6 (p=0.37) and mean body mass index was 15.6 (p=0.36). The prevalence of obstructive sleep apnea was 80% (52 patients) using an apnea hypopnea index cutoff of ≥1 and 7.7% (5 patients) using an apnea hypopnea index cutoff of ≥5. Results from the pediatric sleep questionnaire were snoring (73.8%), apnea (32.8%), and bedwetting (46%). Conclusion: Obstructive sleep apnea is common in children with sickle cell disease.
Project description:Epidemiologic studies on the consequences of sleep-disordered breathing invariably use the apnea-hypopnea index as the primary measure of disease severity. Although hypopneas constitute a majority of disordered breathing events, significant controversy remains about the best criteria used to define these events.The current investigation sought to assess the most appropriate definition for hypopneas that would be best correlated with cardiovascular disease.A community sample of middle-aged and older adults was recruited as part of the Sleep Heart Health Study. Full-montage polysomnography was conducted and hypopneas were defined using different thresholds of oxyhemoglobin desaturation with and without arousals. Prevalent cardiovascular disease was assessed based on self-report. Logistic regression analysis was used to characterize the independent association between the hypopnea index and prevalent cardiovascular disease.Using a sample of 6,106 adults with complete data on cardiovascular disease status and polysomnography, the current study found that hypopneas associated with an oxyhemoglobin desaturation of 4% or more were associated with prevalent cardiovascular disease independent of confounding covariates. The adjusted prevalent odds ratios for quartiles of the hypopnea index using a 4% desaturation criterion were as follows: 1.00 (<1.10 events/h), 1.10 (1.01-3.20 events/h), 1.33 (3.21-7.69 events/h), and 1.41 (>7.69 events/h). Hypopnea measures based on less than 4% oxyhemoglobin desaturation or presence of arousals showed no association with cardiovascular disease.Hypopneas comprise a significant component of sleep-disordered breathing in the general community. By varying the criteria for defining hypopneas, this study demonstrates that hypopneas with a desaturation of at least 4% are independently associated with cardiovascular disease. In contrast, no association was observed between cardiovascular disease and hypopneas associated with milder desaturations or arousals.