Auditory evoked potentials remain abnormal after CPAP treatment in patients with severe obstructive sleep apnoea

ObjectiveTo assess the effects of 3 months of optimal CPAP treatment on auditory event related potentials (AERP) in patients with severe obstructive sleep apnoea (OSA) compared with healthy controls.MethodsAuditory odd-ball related N1, P2, N2 and P3 AERP components were assessed in 9 severe OSA subjects and 9 healthy controls at baseline evaluation and at ～3 months follow-up in both groups, with OSA subjects treated with continuous positive air-way pressure (CPAP) during this period.ResultsSevere OSA subjects showed significantly delayed, P2, N2 and P3 latencies, and significantly different P2 and P3 amplitudes compared to controls at baseline (group effect, all p < 0.05). At follow-up evaluation P3 latency shortened in treated OSA patients but remained prolonged compared to controls (group by treatment interaction, p < 0.05) despite high CPAP compliance (6 h/night). The earlier AERP (P2 and N2) components did not change in either controls or OSA patients at follow-up and remained different in patients versus controls.ConclusionsThis study demonstrates that in severe OSA patients AERP responses show minimal or no improvement and remain abnormal following 3 months of optimal CPAP treatment.SignificancePersistent cortical sensory processing abnormalities despite treatment in severe OSA may have implications for daytime neurobehavioral performance and safety in OSA patients. AERP responses may help identify residual performance deficits and risks.     

Treatment of obstructive sleep apnoea using nasal CPAP in children with craniofacial dysostoses

We studied a group of children (aged 2.2–15 years) with craniofacial dysostosis and obstructive sleep apnoea to assess the use of nasal continuous positive airway pressure (n-CPAP) as a palliative form of treatment. A variable period of time was allowed for acclimatisation to n-CPAP (1 day to 2 months), depending on the patient. Patients were then admitted for their first CPAP trial. Baseline breathing difficulty and the effectiveness of n-CPAP were assessed by respiratory sleep studies. Successful results were obtained with n-CPAP in five of the eight patients, with marked clinical and polygraphic improvements of the respiratory pattern immediately after n-CPAP was established. Of the remaining three cases, one child needed a prolonged period of acclimatisation to the n-CPAP system, one was withdrawn from the study, and one failed to respond to n-CPAP and was found to have complete blockage of the upper airways as a result of enlarged adenoids. Our results confirm that n-CPAP can be tolerated even by young patients and can be effective, and that it may be a useful alternative palliative treatment for obstructive sleep apnoea in children with craniofacial syndromes.Presented at the Consensus Conference on Craniosynostoses, Rome, 4–6 May 1995     

Cerebral metabolic impairment in patients with obstructive sleep apnoea: an independent association of obstructive sleep apnoea with white matter change

OBJECTIVES: To determine the relation between severity of obstructive sleep apnoea (OSA) and degree of cerebral metabolic impairment. METHODS: Fifty five patients with habitual snoring and excessive daytime sleepiness underwent standard overnight polysomnography and magnetic resonance spectroscopy separately. Proton MR spectra were measured with two dimensional chemical shift imaging (repetition time; 1500 ms, echo time; 135 ms). Severity of cerebral metabolic impairment was assessed by the N-acetylaspartate (NAA)/choline ratios for the cerebral cortex and white matter. Severity of OSA was assessed by the apnoea-hypopnoea index (AHI) and the minimum value of peripheral oxyhaemoglobin saturation. All patients were evaluated for the presence or absence of comobidities including hypertension, cardiac disease, diabetes mellitus, and hyperlipidaemia. Univariate analysis of variance (ANOVA) and mulitple linear regression analysis were used for statistical analyses. RESULTS: Univariate ANOVA disclosed significant effects of AHI, age, and the presence or absence of hypertension on the NAA/choline ratio for cerebral white matter (p=0.011, p=0.028, p=0.0496, respectively). The AHI had a significant negative association with the NAA/choline ratio for cerebral white matter, independent of age and the presence or absence of cardiac disease, in the final multivariate regression model (standardised partial regression coefficient=-0.417, p<0.001). No significant relation was found between severity of OSA and the NAA/choline ratio for the cerebral cortex. Age alone had a significant effect on the NAA/choline ratio for the cerebral cortex on univariate ANOVA (p<0.001) and a significant negative association with the NAA/choline ratio for the cerebral cortex in the regression model (r=-0.552, p<0.001). CONCLUSIONS: A significant relation exists between AHI and the degree of metabolic impairment in cerebral white matter in patients with OSA.     

The impact of obstructive sleep apnoea severity on cardiac structure and injury

BackgroundObstructive sleep apnoea (OSA) is an important factor in the development and progression of heart failure (HF). The prevalence of OSA is higher in patients with HF than in the general population. We sought to test the hypothesis that OSA severity was predictive of ventricular function and cardiac injury [as assessed by high-sensitivity cardiac troponin I(hs-cTnI)].MethodsA total of 60 patients were recruited after evaluation for sleep disturbances using the Jenkins Sleep Questionnaire (JSQ) and Epworth Sleepiness Scale (ESS). Subsequently, they underwent polysomnography thus confirming the diagnosis of OSA and were equally divided into three groups according to OSA severity grade. Following polysomnography, the next morning patients underwent venous blood sampling and echocardiography.ResultsWe observed a statistically significant association (P = 0.009) between diastolic dysfunction grades and severity grades of OSA. All the three diastolic dysfunction variables E/A ratio, deceleration time and E/e’ ratio had a significant association(P < 0.05) with severity grades of OSA. There was a marginally significant positive correlation (ρ = 0.3244, p = 0.04) between AHI events per hour and mitral E/e’ ratio. There was a statistically significant association(P < 0.001) between hs-cTnI value among different severity grades of OSA.ConclusionsHere in our study, we found OSA a potential risk factor for development of myocardial injury and diastolic dysfunction. Severe grades of OSA are associated with higher grades of diastolic dysfunction and circulating levels of hs-cTnI. These data are consistent with the notion of a vicious cycle of frequent apnoea's or hypoxemia and recurrent myocardial injury, which could increase the risk of heart failure especially diastolic dysfunction in OSA.     

CPAP treatment in obstructive sleep apnoea: A randomised, controlled trial of follow-up with a focus on patient satisfaction

Aim of the studyTo assess a simplified model for follow-up in patients undergoing CPAP-treatment for obstructive sleep apnoea syndrome.Patients and methodsA total of 200 patients in stable condition were randomised to annual follow-up visits either by a specialist nurse (intervention) or physician-led visits including oximetry (control). Patients were followed for two years and assessed for the following outcomes: global satisfaction, quality of life, medical events, and resource utilisation.ResultsThe overall experience of CPAP treatment was rated as excellent or good by 99% in each group. Global satisfaction was high in both groups, and there were no clinically significant differences between the groups. Quality of life did not differ between the groups. No serious medical events related to OSAS occurred during the study period. Extra physician consultations occurred rarely, and were managed within the limits of the follow-up visits.ConclusionFor stable patients undergoing CPAP treatment for obstructive sleep apnoea, regular follow-up visits by a specialist nurse can optimise the use of health care resources while retaining high patient satisfaction, without increasing medical risks.     

Autonomic nervous system function in patients with primary obstructive sleep apnoea syndrome

Ten patients with obstructive sleep apnoea syndrome cured by uvulopalatopharyngoplasty were compared to nine patients considered as surgical failures, using cardiovascular reflex tests—Valsalva manoeuvre, respiratory sinus arrhythmia, isometric handgrip and head-up tilt. Two patients had signs of moderate vagal dysfunction, but no case of definite autonomic nervous dysfunction was diagnosed. The overall results indicated sympathetic overreactivity, positively correlated to oxygen desaturation indices and remaining after successful treatment. Four patients did not exhibit bradycardia during sleep apnoea. Two of them had decreased respiratory sinus arrhythmia when awake, but two had normal values. This implies a difference in vagal responsiveness between the awake and sleeping states, or that other factors besides vagus function influence the bradycardia response to apnoea. The group mean values were all within normal limits. There was no significant difference between the two groups in any test. Autonomic nervous dysfunction therefore does not seem to contribute to surgical failure, nor to occur with increased incidence among patients with primary obstructive sleep apnoea syndrome.     

Preference for fixed or automatic CPAP in patients with obstructive sleep apnea syndrome

BACKGROUND: The aims of this study were to compare compliance to treatment with fixed CPAP and with autoCPAP, subjective preference for type of CPAP treatment, and factors associated to preference for autoCPAP in patients with OSAS. PATIENTS AND METHODS: Twenty-two subjects were studied in a randomized, single blind cross-over fashion. They were treated for one month by fixed CPAP (Elite Sullivan V, ResMed, Sydney, Australia) and one month by autoCPAP (Autoset T, ResMed, Sydney, Australia). RESULTS: Four subjects who stated a preference for fixed CPAP and four who expressed no preference were pooled together; fourteen preferred autoCPAP. Compliance to treatment using the two machines did not differ in the first group (3.8 (1.9) vs. 3.8 (1.5)h/day, fixed vs autoCPAP), but was higher with autoCPAP in the second group (4.8 (1.8) vs 5.5 (1.5)h/day, P<0.05). Baseline apnea/hypopnea index (AHI) was high in both groups, but was higher in the second group P<0.02. First treatment was always fixed CPAP in patients who preferred fixed CPAP, while it was either in the other subjects. CONCLUSIONS: Compliance to autoCPAP differs among OSAS patients. As long as factors predicting higher compliance to autoCPAP are not found, a trial with autoCPAP in patients poorly compliant to fixed CPAP may be warranted.     

Impact of CPAP treatment on leptin and adiponectin in adults with coronary artery disease and nonsleepy obstructive sleep apnoea in the RICCADSA trial

BackgroundIncreased leptin and decreased adiponectin levels are reported in coronary artery disease (CAD) as well as in obstructive sleep apnoea (OSA). Less is known regarding the impact of continuous positive airway pressure (CPAP) on these biomarkers. We aimed to determine variables associated with leptin and adiponectin in adults with CAD and nonsleepy OSA, and evaluate the effect of CPAP adjusted for confounding factors.MethodsThis was one of the secondary outcomes of the RICCADSA trial, conducted in Sweden between 2005 and 2013. From 244 revascularized CAD and OSA patients (apnoea–hypopnoea index >15/h) without excessive daytime sleepiness (Epworth Sleepiness Scale score <10), 196 with blood samples at baseline, after 3, and 12 months were included in the randomized controlled trial arm; of those, 98 were allocated to auto-titrating CPAP, and 98 to no-CPAP.ResultsNo significant changes in leptin and adiponectin levels were observed during follow-up, whereas Body-Mass-Index and waist circumference increased in both CPAP and no-CPAP groups with no significant between-group differences. Alterations in plasma leptin were determined by changes in waist circumference (beta coefficient 2.47; 95% confidence interval 0.77–4.40), whereas none of the analyzed parameters was predictive for changes in adiponectin levels. No association was found with CPAP adherence.ConclusionsCPAP had no significant effect on leptin and adiponectin in this cohort of nonsleepy OSA patients. An increase in waist circumference predicted an increase in plasma levels of leptin after 12 months, suggesting that lifestyle modifications should be given priority in adults with CAD and OSA regardless of CPAP treatment.     

The pulse transit time arousal index in obstructive sleep apnea before and after CPAP

BACKGROUND AND PURPOSE: Pulse transit time (PTT) is a non-invasive index which reflects changes in peripheral vascular resistance and intrathoracic pressure. PTT arousal index (PTT Ar/I) is defined as the frequency (number/hour) of a defined decrease in PTT which may serve as a marker for respiratory events, and associated arousals which occur in patients with obstructive sleep apnea (OSA). This study was designed to evaluate the PTT Ar/I before and after patients with OSA were treated with continuous positive airway pressure (CPAP). PATIENTS AND METHODS: Individuals referred for evaluation of possible OSA underwent split-night polysomnography (PSG). The findings from 144 consecutive patients with a respiratory disturbance index (RDI)>/=20, who demonstrated at least a 50% drop in RDI with CPAP, provide the basis for this analysis. The PTT Ar/I measured before and after CPAP were compared to other measures of severity for OSA, including RDI and arousal index. RESULTS: The PTT Ar/I correlates with the RDI (r=0.43, P相似文献   

Comparative effects of CPAP and mandibular advancement splint therapy on blood pressure variability in moderate to severe obstructive sleep apnoea

BackgroundObstructive sleep apnoea (OSA) is associated with increased blood pressure variability (BPV) and are risk factors for cardiovascular disease. We aimed to assess the comparative effects of two OSA therapies, continuous positive airway pressure (CPAP) and mandibular advancement splint (MAS), on BPV.MethodsThis is a secondary analysis of data collected as part of a previously published randomised crossover trial of one month each of CPAP and MAS therapy. BPV was determined from 24-h-ambulatory blood pressure recordings in 92 patients with moderate to severe OSA at baseline and after one month of optimised treatment with each modality. BPV was assessed by three measures: Standard deviation of the mean (SD), Coefficient of variation (CoV), and the Average Real Variability (ARV) index.ResultsNeither CPAP nor MAS therapy improved BPV, with no difference between treatments. BPV did not change in hypertensive OSA patients, however, there was a reduction in ARV of diastolic blood pressure in the effectively treated compared to ineffectively treated CPAP patients, Δ ARV 24-h-DBP (mmHg), −0.72 ± 2.14, 0.34 ± 1.52, P = 0.02, respectively. There was no difference between effective versus ineffective MAS treatment, Δ ARV 24-h-DBP (mmHg), −0.04 ± 2.4, 0.02 ± 1.9, P = 1.00, respectively.ConclusionsOne month of optimised CPAP or MAS therapy did not improve short term BPV in patients with moderate to severe OSA. The subgroup of patients on effective CPAP showed some improvement in BPV with CPAP but not MAS. Further work on the effect of OSA therapy on BPV following long-term therapy is needed.     

Improving CPAP use by patients with the sleep apnoea/hypopnoea syndrome (SAHS)

Though continuous positive airway pressure (CPAP) is the treatment of choice for the sleep apnoea/hypopnoea syndrome (SAHS), suboptimal adherence to CPAP is common. Internationally, some 5-50% of SAHS patients recommended for CPAP either reject this treatment option or discontinue within the first week, and 12-25% of remaining patients can be expected to have discontinued CPAP by 3 years. Biomedical investigations of patients' CPAP use reveal frequent adverse effects, weak prospective relationships between symptomatic or physiological disease severity and CPAP use, and moderate correlations between use and benefit. Relatively expensive high-technological interventions to improve CPAP use (e.g. "intelligent" CPAP, humidification) are the subject of several well-conducted studies favouring their effectiveness. More basic educational and behavioural supports, and low-technological interventions (e.g. chinstraps, mask re-fitting) appear valued, but are currently less rigorously evaluated. In other diseases with demanding treatment regimens, cognitive constructs including health attitudes and beliefs (health value, locus of control, chance, powerful others, self-efficacy) and mental and physical health status are significant predictors of adherence. The enhancement of multidisciplinary models with psychosocial interpretations may provide increased explanatory and interventional potential in models of CPAP use. While acknowledging the scarcity of evidence, a structured, multidisciplinary, cost-efficient model is suggested, containing educational, behavioural and technological components as basic support, and with high-expertise cognitive-behavioural intervention in more difficult cases of low CPAP use.     

Adaptive servo-ventilation in patients with coexisting obstructive sleep apnoea/hypopnoea and Cheyne-Stokes respiration

ObjectiveThe coexistence of obstructive (OSAS) and central sleep apnoea (CSA) and Cheyne–Stokes respiration (CSR) is common in patients with and without underlying heart diseases. CPAP has been shown to improve CSA/CSR by about 50%, but recent data suggest maximal suppression of CSA is important in improving clinical outcomes in heart failure patients. Adaptive servo-ventilation (ASV) effectively suppresses CSA/CSR in heart failure, but only few trials have considered patients with coexisting OSAS and CSA/CSR.MethodsProspective, observational pilot study to evaluate the efficacy of a new ASV device, the BiPAP AutoSV, in 10 male consecutive patients with coexisting OSAS and CSA/CSR with and without heart failure over eight weeks. Six had stable heart failure.Measurements and ResultsThe total AHI improved from 48.9 ± 20.6/h to 8.7 ± 7.4, the obstructive AHI from 15.8 ± 16.2/h to 2.6 ± 2.5/h and the central AHI from 33.1 ± 10.8/h to 6.1 ± 5.9/h (all p < 0.01). Furthermore, there was a significant improvement in sleep profile and respiratory related arousals. The six patients with cardiovascular disease, including three with congestive heart failure, showed similar improvements in all parameters.ConclusionsBiPAP AutoSV was effective in reducing all types of respiratory disturbances in coexisting OSAS and CSA/CSR with and without heart failure. Further studies comparing the long-term clinical efficacy of this device against CPAP are warranted.     

Association between plasma homocysteine levels and obstructive sleep apnoea in patients with ischaemic stroke

We aimed to investigate the association between plasma homocysteine and obstructive sleep apnoea (OSA) syndrome in patients with ischaemic stroke. A total of 102 patients with ischaemic stroke were classified into four OSA groups based on their apnoea–hypopnoea index (AHI): absent (AHI < 5/hour); mild (5–14/hour); moderate (15–30/hour); and severe (>30/hour). The mean (±standard deviation) homocysteine levels in the four OSA groups were: absent, 8.98 ± 3.74 μmol/L; mild, 11.46 ± 3.31 μmol/L; moderate, 14.18 ± 4.36 μmol/L; and severe, 18.57 ± 4.56 μmol/L; and these differences were statistically significant (p < 0.001). The Pearson correlation analysis revealed a positive correlation between homocysteine levels and the severity of AHI (r = 0.482, p < 0.001). Multiple linear regression analysis showed that AHI and folate were independent predictors of homocysteine levels (R² = 0.539, p < 0.001, β for AHI = 0.259, β for folate = –0.400). In conclusion, the severity of OSA is significantly associated with elevated homocysteine levels in patients with ischaemic stroke, and this association is independent of other factors that cause elevation in homocysteine.     

Topographic differences in mean computational sleep depth between healthy controls and obstructive sleep apnoea patients

In this work, topographic differences in computational sleep depth between healthy controls and obstructive sleep apnoea syndrome (OSAS) patients have been examined. Sleep depth estimation was based on continuous monitoring of the mean frequency of the EEG. During the experiments, all-night sleep EEG recordings of carefully age and gender matched sets of 16 healthy controls and 16 OSAS patients were compared on six electrode locations (Fp1-M2, Fp2-M1, C3-M2, C4-M1, O1-M2, and O2-M1). To optimise the diagnostic ability of the method, we examined the influence of 45 sets of adjustable analysis parameters on the ability of the method to show differences in computational sleep depth between the diagnostic groups. The results show clearly that although the visual scores for a set of epochs are the same for both clinical groups, computational sleep depth measure still shows deeper local sleep for healthy controls, both during NREM and REM sleep. Although the best achievable performance in different sleep stages is reached in different EEG derivations and with different parameter values, computation of sleep depth with 1-s output resolution in non-overlapping segments of 2s (400 samples) with maximum analysis band frequency of 20.5 Hz and 51-point moving median smoothing on Fp2-M1 or O1-M2 leads to near-optimal performance in deep sleep or wakefulness/light sleep, respectively.     

Effect of CPAP on QT interval dispersion in obstructive sleep apnea patients without hypertension

OBJECTIVES: Delayed cardiac repolarization leading to prolongation of the QT interval is a well-characterised precursor of arrhythmias. Obstructive sleep apnea (OSA) might cause arrhythmias, since QT corrected interval dispersion (QTcd) is increased in these patients. We aimed to determine the effect of nasal continuous positive airway pressure (CPAP) therapy on QTcd in OSA patients without hypertension. METHODS: An overnight polysomnography (PSG) and a standard 12-lead electrocardiogram (ECG) were performed on 49 subjects without hypertension, diabetes mellitus, cardiac or pulmonary disease or any hormonal, hepatic, renal or electrolyte disorders. In 29 moderate-severe OSA (apnea-hypopnea index: AHI15) patients, QTd (defined as the difference between the maximum and minimum QT interval) and QTcd were calculated using the Bazzet formula at baseline and after six months of CPAP therapy. RESULTS: Eighteen patients were compliant with nasal CPAP, and mean age was 46.5+/-4.9 years. Patients had high body mass index (BMI: 30.6+/-4.0 kg/m(2)), but there was no change in either BMI or blood pressure after six months. A strong positive correlation was shown between QTcd and AHI (p<0.001, r=0.913). The QTcd at baseline (54.5+/-8.7 ms) significantly decreased after CPAP therapy (35.5+/-4.2 ms, p<0.001), although it did not significantly change in 11 non-compliant patients. CONCLUSION: In OSA patients without hypertension, CPAP therapy improves the inhomogeneity of repolarization via a significant decrease in QTcd.