Does CPAP treatment in mild obstructive sleep apnea affect blood pressure?

ObjectivesObstructive sleep apnea (OSA) is associated with significant cardiovascular (CV) morbidity. Continuous positive airway pressure (CPAP) is the standard treatment for moderate to severe OSA, resulting in a reduction in CV morbidity. No studies have compared CV outcomes between CPAP and no CPAP in mild OSA (5 ? AHI < 15).MethodsRetrospective cohort study of subjects (age ? 18) with mild OSA diagnosed between 2004 and 2006. Subjects with a history of hypertension, angina, stroke and smoking were excluded. Subjects were stratified into two groups: CPAP (n = 93) or no CPAP (n = 162). The mean blood pressures (MBP) were compared 2 years after the diagnosis of OSA was established.ResultsUnmatched for covariates (age, sex, BMI, neck circumference, AHI, arousal index and family h/o CV disorders), subjects with mild OSA on CPAP had a 1.97 point reduction, and no CPAP resulted in a 9.61 point elevation (p < 0.0001) in MBP. With propensity score matching for covariates, the mean difference in MBP was ?1.97 (95% CI: ?14.03, ?9.92; p < 0.0001) with a sensitivity analysis of 2.646.ConclusionThis study shows an elevation of the MBP in mild OSA patients who were not treated with CPAP. CPAP treatment in mild OSA patients decreased the MBP over a 2-year period.     

Continuous positive airway pressure deepens sleep in patients with Alzheimer’s disease and obstructive sleep apnea

ObjectivePatients with Alzheimer’s disease (AD) and obstructive sleep apnea (OSA) experience disrupted sleep. This study examined the effect of continuous positive airway pressure (CPAP) on sleep parameters in AD patients with OSA.MethodsA randomized placebo-controlled trial of 3 weeks of therapeutic CPAP (tCPAP) vs. 3 weeks placebo CPAP (pCPAP) followed by 3 weeks tCPAP in patients with AD and OSA. Polysomnography data from screening after one night and after 3 weeks of treatment were analyzed. Records were scored for percent of each sleep stage, total sleep time (TST), sleep efficiency (SE), sleep period (SP), time in bed (TIB), sleep onset (SO), wake time after sleep onset (WASO), and arousals. A randomized design comparing one night of pCPAP to tCPAP and a paired analysis combining 3 weeks of tCPAP were performed.ResultsFifty-two participants (mean age = 77.8 years, SD = 7.3) with AD and OSA were included. After one treatment night, the tCPAP group had significantly less % Stage 1 (p = 0.04) and more % Stage 2 sleep (p = 0.02) when compared to the pCPAP group. In the paired analysis, 3 weeks of tCPAP resulted in significant decreases in WASO (p = 0.005), % Stage 1 (p = 0.001), arousals (p = 0.005), and an increase in % Stage 3 (p = 0.006).ConclusionIn mild to moderate AD patients with OSA, the use of tCPAP resulted in deeper sleep after just one night, with improvements maintained for 3 weeks.     

Are physicians aware of obstructive sleep apnea in children?

BACKGROUND AND PURPOSE: Childhood obstructive sleep apnea (OSA) affects 1-3% of preschool children. If left untreated, it can result in serious morbidity including growth retardation, cor pulmonale, and neurocognitive deficits, such as poor learning and behavioral problems. Early recognition and treatment is important to prevent morbidity and sequela and to provide better quality of life both for the child and his or her family members. The purpose of this study was to elucidate the knowledge and attitude physicians have about pediatric OSA, using the Obstructive Sleep Apnea Knowledge and Attitudes in Children (OSAKA-KIDS) questionnaire. PATIENTS AND METHODS: The first section of the OSAKA-KIDS questionnaire, which includes 18 items presented in a true-or-false format, was developed to assess the knowledge physicians have about pediatric OSA. The second section, including five items, was developed to assess attitudes and was measured on a five-point Likert scale ranging from 1 to 5. RESULTS: A total of 230 questionnaires were completed by physicians: 138 (60.3%) pediatricians, 70 (30.5%) general practitioners and 21 (9.2%) pulmonologists. The mean total knowledge score was 66.7%. The knowledge score positively correlated with having sub-specialty training (r=0.205, P=0.002) and negatively correlated with having a higher degree (r=-0.283, P<0.001). The mean total attitude score was 3.4. The knowledge score positively correlated with the attitude score (r=0.27, P<0.001). CONCLUSIONS: This study shows that among physicians there are deficits in knowledge about childhood OSA and its treatment. More focused educational programs are needed within medical schools and within pediatric residency and post-graduate training programs.     

Resolution of obstructive sleep apnea with epilepsy surgery? Expanding the relationship between sleep and epilepsy

Recent studies suggest a higher than expected prevalence of obstructive sleep apnea (OSA) in patients with refractory epilepsy. In some cases, treatment of OSA improves seizure control. We report a case in which clinically significant OSA disappeared after left frontal lobe resection that produced a near seizure free state. This occurred in the absence of the usual factors, such as weight or medication change or variation in polysomnography (PSG) recording methodology, that often confound the comparison of sequential PSGs over time. Our patient underwent PSG with 18-channel EEG recording pre- and postoperatively using standardized scoring techniques. Baseline testing revealed an apnea-hypopnea index (AHI) of 24 with severe oxygen desaturations reaching a nadir of 62%. Postoperative testing found both the AHI and oxygen saturation normalized as well as a marked reduction in spike rate. We hypothesize that the pathophysiology of OSA in patients with epilepsy may be impacted by frequent, extensive interictal epileptiform discharges (IEDs) and/or seizures altering upper airway control during sleep.     

Does obstructive sleep apnea confound sleep architecture findings in subjects with depressive symptoms?

BACKGROUND: Compared with normal subjects, depressed patients have shorter rapid eye movement sleep latency (REML), increased REM and decreased slow wave sleep as a percentage of total sleep time (REM%, SWS%), and longer sleep latency (SL). Obstructive sleep apnea (OSA) patients experience longer REML, decreased REM% and SWS%, and shorter SL. We examined the interplay of depressive symptoms, OSA, and sleep architecture. METHODS: Subjects (n = 106) were studied with polysomnography. OSA was defined as a Respiratory Disturbance Index > or = 15. Subjects were divided into Hi/Lo groups using a Center for Epidemiological Studies-Depression (CES-D) score of 16. RESULTS: OSA patients had shorter SL than non-OSA patients (14.5 vs. 26.8 min, p <.001); Hi CES-D subjects showed a trend toward longer SL than Lo CES-D subjects (23.7 vs. 17.5 min, p =.079). Significant OSA x CES-D interactions emerged, however, for REM% (p =.040) and SL (p =.002): OSA/Hi CES-D subjects had higher REM% than OSA/Lo CES-D subjects (19.3% vs. 14.3%, p =.021); non-OSA/Hi CES-D subjects had SL (35.3 min) 2-3 times as long as other subjects (p =.002-.012). CONCLUSIONS: Because of the high prevalence of OSA and depression, findings suggest that OSA must be considered in studies of mood and sleep architecture. Conversely, depressive symptoms must be considered in studies of OSA and sleep architecture.     

Does continuous positive airway pressure treatment affect autonomic nervous system in patients with severe obstructive sleep apnea?

ObjectiveThis study is aimed at evaluating whether Continuous Positive Airway Pressure treatment (CPAP) may affect autonomic nervous system (ANS) in male patients with severe obstructive sleep apnea (OSAS).MethodsWe compared autonomic symptoms of de novo severe OSAS patients, OSAS patients on chronic CPAP treatment and healthy controls, using the Scales for Outcome in Parkinson disease-Autonomic (SCOPA-AUT) questionnaire. All groups underwent cardiovascular function tests including head-up tilt test (HUTT), Valsalva maneuver, deep breathing, hand grip and cold face tests. Statistical significance was set at p < 0.05.ResultsTwelve de novo severe OSAS patients, 17 male OSAS on CPAP and 14 controls were studied. The mean SCOPA-AUT total score was significantly higher in de novo OSAS patients compared with controls. Regarding the distinct domains, both de novo OSAS and CPAP group had abnormalities in respect of controls in urinary sphere. In supine rest condition the baseline values of systolic blood pressure were significantly increased in untreated OSAS patients compared with controls, whereas the basal values of diastolic blood pressure were significantly higher in CPAP patients with respect to controls. After ten min of HUTT, diastolic blood pressure changes were significantly higher in controls compared to both OSAS groups. Untreated OSAS patients showed significant different responses at deep breathing compared to controls. Both OSAS groups had a significant reduction of reflex bradycardia at cold face test.ConclusionsOur study shows that both treated and untreated OSAS patients complain of subjective autonomic symptoms like other sleep disorders reinforcing the close relationship between sleep and autonomic activity. Furthermore, cardiovascular reflexes indicate a tendency to hypertension and a reduced sensitivity to stimuli during wakefulness even in OSA patients on CPAP treatment, suggesting potentially permanent autonomic function deficits.     

Estimation of parasympathetic nerve function during sleep in patients with obstructive sleep apnea by instantaneous time–frequency analysis

Background and objectivesThe pathophysiologic aspects of parasympathetic nerve (PN) function during sleep in patients with obstructive sleep apnea (OSA) studied by classical power spectrum analysis on heart rate variability (HRV) are highly controversial. The controversy is attributed to methodologic concerns, such as poor time resolution involved in power spectrum analysis. We aimed to establish the appropriate method for the investigation of PN function in OSA patients with apneas and hypopneas using instantaneous time–frequency analysis with complex demodulation (CD) and sufficient time resolution.MethodsA total of 30 patients with PSG-confirmed mild to severe OSA were recruited for the analysis of frequency spectra contained in R-R intervals (RRI) of overnight electrocardiograph (ECG) tracings. High-frequency (HF) domains ranging between 0.15 and 0.40 Hz were selected for analysis. Among these domains, the HF domain with the maximum instantaneous amplitude was defined as the main HF peak and was used as the surrogate marker of PN discharge. Based on density spectrum array (DSA) map for main HF peak constructed with a time scale of 1 s and a frequency resolution of 0.002 Hz (HF-DSA map), the shift in central frequency (CF) of main HF peak over time was continuously monitored. When the main HF peak with the same CF lasted for more than 20 s or 5 min on HF-DSA map, the PN function was considered to be stable or very stable. The measurements were then repeated after continuous positive airway pressure (CPAP) treatment.ResultsThe extent of PN-evoked modulation of RRI was enhanced in nonrapid eye movement (NREM) sleep, though the stability was reduced in both NREM and rapid eye movement (REM) sleep. These peculiar behaviors of PN function were reversed by CPAP treatment.ConclusionWe found that instantaneous time–frequency analysis allowed estimation of transitional changes in PN function during sleep in OSA patients.     

Anticyclic modulated ventilation versus continuous positive airway pressure in patients with coexisting obstructive sleep apnea and Cheyne–Stokes respiration: a randomized crossover trial

BackgroundAlthough coexisting obstructive sleep apnea (OSA) and Cheyne–Stokes respiration (CSR) occur frequently in patients with heart diseases, optimal treatment remains unclear. Positive airway pressure (PAP) effectively treats OSA and adaptive servo-ventilation (ASV) has been shown to improve CSR. We compared a new treatment algorithm combining automatic continuous positive airway pressure (APAP) and ASV (anticyclic modulated ventilation, ACMV) versus continuous positive airway pressure (CPAP).MethodsThirty-nine patients (35 male, four female; aged 65.5 ± 9.7 years; body mass index, 31.0 ± 5.9 kg/m²) with underlying heart disease and coexisting OSA and CSR were enrolled. After diagnostic polysomnography (PSG) and CPAP titration, patients were randomized either to CPAP or to ACMV for four weeks of treatment in a crossover design.ResultsTotal apnea–hypopnea index (AHI) was 49.0 ± 18.8/h at baseline, 12.3 ± 14.6/h with CPAP (P < 0.001 vs baseline), and 3.7 ± 5.6/h with ACMV (P < 0.001 vs baseline and vs CPAP). Obstructive AHI was 20.7 ± 14.4/h at baseline, 5.1 ± 9.3/h with CPAP (P < 0.001 vs baseline), and 0.4 ± 0.4/h with ACMV (P < 0.001 vs baseline and vs CPAP). Central AHI was 28.3 ± 13.4/h at baseline, 7.2 ± 9.7/h with CPAP (P < 0.001 vs baseline) and 3.3 ± 5.4/h with ACMV (P < 0.001 vs baseline and vs CPAP). Ejection fraction was increased significantly (from 38.6 ± 15.6 to 44.4 ± 12.2%) only with ACMV. Subjective sleepiness significantly improved only with CPAP whereas objective sleep quality and treatment adherence were not different between both treatment modalities.ConclusionACMV is an effective treatment option in patients with coexisting OSA and CSR. It is superior to CPAP in reducing total AHI as well as obstructive and central AHI.     

Is obstructive sleep apnea associated with cortisol levels? A systematic review of the research evidence

The pathophysiology of obstructive sleep apnea (OSA) has been associated with dysregulation of the hypothalamic pituitary adrenal (HPA) axis; however a relationship between OSA and altered cortisol levels has not been conclusively established. We conducted a systematic review using the PRISMA Guidelines based on comprehensive database searches for 1) studies of OSA patients compared to controls in whom cortisol was measured and 2) studies of OSA patients treated with continuous positive airway pressure (CPAP) in whom cortisol was measured pre and post treatment. Five electronic databases were searched along with the reference lists of retrieved studies. The primary outcomes were 1) differences in cortisol between OSA and control subjects and 2) differences in cortisol pre-post CPAP treatment. Sampling methodology, sample timing and exclusion criteria were evaluated. Fifteen studies met the inclusion criteria. Heterogeneity of studies precluded statistical pooling. One study identified differences in cortisol between OSA patients and controls. Two studies showed statistically significant differences in cortisol levels pre-post CPAP. The majority of studies were limited by assessment of cortisol at a single time point. The available studies do not provide clear evidence that OSA is associated with alterations in cortisol levels or that treatment with CPAP changes cortisol levels. Methodological concerns such as infrequent sampling, failure to match comparison groups on demographic factors known to impact cortisol levels (age, body mass index; BMI), and inconsistent control of variables known to influence HPA function may have limited the results.     

Prevalence of central sleep apnea during continous positive airway pressure (CPAP) titration in subjects with obstructive sleep apnea syndrome at an altitude of 2640 m

BackgroundThe occurrence of central apneas when applying positive pressure (CPAP) to patients with obstructive sleep apnea syndrome (OSAS) is called complex sleep apnea (CompSA). This causes poor adherence to CPAP and persistence of symptoms. In Bogota, a city located at an altitude of 2640 m above sea level, chronic hypoxemia can generate certain instability of the respiratory system during sleep which could increase the presence of central apnea. The aim was to establish the prevalence of central apnea (central apnea index >5/h) in adults with moderate or severe OSAS during CPAP titration, and the factors associated with this.MethodPatients over 18 years old with OSAS were referred to the Fundacion Neumologica Colombiana Sleep Center, from January 2008 to June 2010. Polysomnogram (PSG) for CPAP titration was performed according to the American Academy of Sleep Medicine criteria. The prevalence was calculated and the clinical and baseline PSG factors associated with the CompSA were analyzed.ResultsWe included 988 patients, 58% men. CompSA prevalence was 11.6%. Factors associated with CompSA were: central apneas in the baseline PSG (OR: 5.34 [3.49–8.16]), history of heart failure (OR: 2.53 [1.58–4.07]), and male sex (OR: 1.68 [1.06–2.69]).ConclusionThe prevalence of complex sleep apnea in Bogota (11.6%) was intermediate compared to the reported in lower altitudes. The factors associated with the development of CompSA were male sex, heart failure, and the presence of central apnea in the baseline PSG.     

Insufficient sleep rather than the apnea–hypopnea index can be associated with sleepiness-related driving problems of Japanese obstructive sleep apnea syndrome patients residing in metropolitan areas

ObjectiveObstructive sleep apnea syndrome (OSAS) and insufficient sleep might increase the risk of drowsy driving and sleepiness-related vehicular accidents. This study retrospectively investigated the factors associated with these driving problems, particularly addressing OSAS severity and sleep amounts of affected drivers.MethodsThis study examined 161 patients (146 male and 15 female) with OSAS (apnea−hypopnea index [AHI] ≥ 5) who drove on a routine basis and who completed study questionnaires. To investigate factors associated with drowsy driving during the prior year and sleepiness-related vehicular accidents or near-miss events during the prior five years, logistic regression analyses were performed with age, body mass index, monthly driving distance, habitual sleep duration on weekdays, the Japanese version of Epworth Sleepiness Scale score, AHI, and periodic limb movement index as independent variables.ResultsOf the patients, 68 (42.2%) reported drowsy driving experiences, and 86 (53.4%) reported sleepiness-related vehicular accidents or near-miss events. Analyses revealed the following: older age (46–65 years, ≥66 years) was negatively associated with drowsy driving (p <0.05, p <0.05), and habitually shorter sleep duration on weekdays (≤6 hours) was positively associated with drowsy driving (p <0.01). Habitual sleep duration of ≤6 hours (p <0.01) and Epworth Sleepiness Scale score of ≥11 (p <0.01) were positively associated with sleepiness-related vehicular accidents and near-miss events. However, AHI was not associated with these driving problems.ConclusionInsufficient sleep, rather than severity of OSAS, was associated with sleepiness-related driving problems in these Japanese OSAS patients.     

Uvulopalatopharyngoplasty with or without tonsillectomy in the treatment of adult obstructive sleep apnea – A systematic review

BackgroundThe most commonly performed surgical procedure for obstructive sleep apnea (OSA) is uvulopalatopharyngoplasty with or without tonsillectomy (UPPP ± TE). However, there is currently no review solely focusing on clinically relevant effects of standard UPPP technique with or without tonsillectomy as a monotherapy in patients with OSA.MethodsA systematic review and meta-analysis were performed to assess the effects of isolated UPPP ± TE in patients with OSA. Studies of any design referring to adult patients with obstructive sleep apnea diagnosed via polysomnography or comparable objective measures were considered, in which isolated “standard” UPPP ± TE was performed.ResultsForty-eight studies were included for the qualitative analysis. All but one study demonstrated a reduction in the frequency of respiratory events and success/response rates ranged from 35 to 95.2%. In the six studies that reported pre- and postoperative mean scores of the Epworth Sleepiness Scale (ESS), a reduction in sleepiness scores was demonstrated. Data addressing the effect of UPPP ± TE in comparison to no treatment or control were available from two randomized controlled trials (RCT). When pooling the data, UPPP ± TE was significantly more effective in reducing the apnea-hypopnea index (AHI) and Epworth Sleepiness Scale (ESS) (large effect): an AHI mean difference (MD) of −18.59 (95% CI −34.14, −3.04) and an ESS MD of −5.37 (95% CI −7,03, −3.72). Data addressing effect of UPPP ± TE in comparison to baseline was available from three RCT. When pooling the data, the AHI was reduced from a mean 35.4 to 17.9 (49.5% reduction); a MD of −20.41, 95% CI −32.78, −8.04 (−1.80, −1.15) (large effect). Various additional beneficial effects of UPPP ± TE were demonstrated including improvement in sexual function, ventricular function, sleep stages, serum lipid, depressive disorder and driving performance.ConclusionUPPP ± TE reduces respiratory events and daytime sleepiness in adult patients with OSA and UPPP ± TE is superior to non-treated controls in this regard. Further research is needed to establish the long-term benefit, the impact on cardiovascular morbidity and the role of UPPP ± TE in the variety of available treatment options for OSA.     

Sleep and circadian variability in people with delayed sleep–wake phase disorder versus healthy controls

Objective/BackgroundTo compare sleep and circadian variability in adults with delayed sleep–wake phase disorder (DSWPD) to healthy controls.Patients/MethodsForty participants (22 DSWPD, 18 healthy controls) completed a ten-day protocol, consisting of DLMO assessments on two consecutive nights, a five-day study break, followed by two more DLMO assessments. All participants were instructed to sleep within one hour of their self-reported average sleep schedule for the last four days of the study break. We analyzed the participants' wrist actigraphy data during these four days to examine intraindividual variability in sleep timing, duration and efficiency. We also examined shifts in the DLMO from before and after the study break.Results and conclusionsUnder the same conditions, people with DSWPD had significantly more variable wake times and total sleep time than healthy controls (p ≤ 0.015). Intraindividual variability in sleep onset time and sleep efficiency was similar between the two groups (p ≥ 0.30). The DLMO was relatively stable across the study break, with only 11% of controls but 27% of DSWPDs showed more than a one hour shift in the DLMO. Only in the DSWPD sample was greater sleep variability associated with a larger shift in the DLMO (r = 0.46, p = 0.03). These results suggest that intraindividual variability in sleep can be higher in DSWPD versus healthy controls, and this may impact variability in the DLMO. DSWPD patients with higher intraindividual variability in sleep are more likely to have a shifting DLMO, which could impact sleep symptoms and the optimal timing of light and/or melatonin treatment for DSWPD.Clinical trialCircadian Phase Assessments at Home, http://clinicaltrials.gov/show/NCT01487252, NCT01487252.