Insomnia symptoms influence CPAP compliance

Purpose

The aim of this study is to determine parameters which influence 6-month compliance of continuous positive airway pressure therapy (CPAP) in patients with obstructive sleep apnea syndrome (OSAS).

Methods

This prospective study investigated 73 patients (24 females) with OSAS and medical indication for CPAP therapy: age 55.1?±?11.5 years, body mass index (BMI) 30.8?±?5.0 kg/m2, Apnea–Hypopnea Index (AHI) 39.2?±?26.7/h, Oxygen Desaturation Index (ODI) 33.2?±?25.4/h, minimum O₂ saturation 78.9?±?7.6%. The influence of baseline parameters (demographic and polysomnographic data, sleeping medication intakes, BMI, psychometrics [Epworth Sleepiness Scale, Regensburg Insomnia Scale, Vigilance test and Beck Depression Inventory]) on 6-month compliance was evaluated with a correlation and a linear regression analysis.

Results

The baseline value of the Regensburg Insomnia Scale (RIS) predicts 6-month CPAP compliance (r?=??0.376, R ²?=?0.14, p?<?0.001), although no other baseline parameter correlates. Patients with a compliance of <4 h/night show higher RIS scores, i.e., more insomnia symptoms (17.6?±?8.8) compared to those with ≥4 h/night (12.6?±?6.9; p?<?0.05).

Conclusions

Insomnia symptoms prior to the beginning of CPAP treatment show a negative influence on CPAP compliance. Further studies should clarify, if a treatment of insomnia symptoms leads to a benefit in compliance.     

The relationship between cephalometric carotid artery calcification and Framingham Risk Score profile in patients with obstructive sleep apnea

Purpose

The morbidity rate of arteriosclerosis becomes clinically manifested as acute cardiovascular events. In the progress of atherosclerosis, the carotid artery calcifies and sometimes appears as a calcified mass on a cephalometric radiograph. This study was designed to evaluate cardiovascular risks according to the Framingham Risk Score (FRS) between subjects with and without visible carotid artery calcification on a cephalogram.

Methods

Subjects diagnosed with obstructive sleep apnea (OSA) were divided into two groups according to whether or not calcification was visible on a cephalometric radiograph in the carotid artery area, and the characteristic differences between the two groups were analyzed. The evaluated variables included age, BMI, apnea–hypopnea index (AHI), SpO₂, ESS, blood pressure, medication history, diabetes mellitus (DM), drinking, smoking, and lipid-related measurements. FRSs for stroke, general cardiovascular disease (GCD), and coronary heart disease (CHD) were calculated. Statistical analyses were performed (SPSS 18.0) with significance defined as a two-tailed p value less than 0.05.

Results

A total of 811 subjects completed the data collection (727 males, age 53.0?±?12.5 years, AHI 31.7?±?22.6, times/h). From FRSs, probabilities of a GCD, stroke, and CHD within 10 years were 16.0?±?9.7, 9.8?±?6.7, and 11.9?±?8.3 %, respectively. Some 84 subjects exhibited calcification in the carotid arterial area. Calcification subjects were higher GCD risk and older than subjects who had no identified calcification (20.3?±?10.1 vs 15.6?±?20.3 %, p?=?0.013, 58.8?±?11.4 vs. 52.3?±?12.5 years, p?<?0.001). Although there is no significant difference in OSA-related variables and FRSs, subjects with visible calcifications have higher prevalence of high blood pressure medication and DM (p?<?0.01).

Conclusion

While the presence of a calcified mass on a cephalometric radiograph is not diagnostic of atherosclerosis, this information indicates some cardiovascular risk.     

Validity of sheet-type portable monitoring device for screening obstructive sleep apnea syndrome

Purpose

The SD-101 is a non-restrictive sheet-like medical device that measures sleep-disordered breathing using pressure sensors that can detect the gravitational alterations in the body that accompany respiratory movement. One report has described that the screening specificity of the SD-101 for mild to moderate obstructive sleep apnea syndrome (OSAS) is relatively low. The present study examines whether the accuracy of the SD-101 for OSAS screening is improved by simultaneously measuring percutaneous oxygen saturation (SpO₂).

Methods

Sixty consecutive individuals with suspected OSAS consented to undergo overnight polysomnography (PSG) together with simultaneous measurements of SD-101 and SpO₂ at our laboratory.

Results

The apnea–hypopnea index (AHI) determined from PSG and the respiratory disturbance index determined from SD-101 measurements significantly correlated (SD-101 alone: r?=?0.871, p?<?0.0001; SD-101 with SpO₂: r?=?0.965, p?<?0.0001). Bland–Altman plots showed a smaller dispersion for the SD-101 with SpO₂ than for the SD-101 alone. The SD-101 with SpO₂ detected an AHI of >15 on PSG with a sensitivity and specificity of 96.9 and 90.5 % compared with 87.5 and of 85.7 %, respectively, of the SD-101 alone.

Conclusions

Simultaneously measuring SpO₂ improved the accuracy of the SD-101 for OSAS screening. Furthermore, this modality appears to offer high sensitivity and specificity for detecting even moderately severe OSAS.     

Pediatric Sleep Survey Instrument—a screening tool for sleep disordered breathing

Purpose

The aim of this study was to assess the construct validity and clinical application of the Pediatric Sleep Survey Instrument (PSSI) as a tool to screen for sleep disordered breathing (SDB) in children.

Methods

Polysomnography (PSG) outcomes and PSSI subscale scores were compared between a clinical cohort (N?=?87, 5–10 years, 62 M/25 F) and a nonsnoring community sample (N?=?55, 5–10 years, 28 M/27 F). Group comparisons assessed the ability of the PSSI subscales to discriminate between the clinical and community cohorts. Receiver operating characteristic (ROC) curves assessed construct validity, with the Apnea/Hypopnea Index (AHI) >5 events/h, OSA-18 score >60, and Pediatric Daytime Sleepiness Scale (PDSS) above the 70th percentile as the target references.

Results

The clinical group had more respiratory events, respiratory-related arousals, fragmented sleep, and lower oxygen saturation nadir than the community group (p?<?0.001 for all). PSSI subscale scores of Morning Tiredness, Night Arousals, SDB, and Restless Sleep were higher (p?<?0.001 for all) in the clinical cohort, confirming the tool’s ability to identify clinically relevant sleep problems. ROC curves confirmed the diagnostic accuracy of the SDB subscale against an AHI?>?5 events/h (area under the curve (AUC)?=?0.7), an OSA-18 score >60 (AUC?=?0.7), and a PDSS score in the 70th percentile (AUC?=?0.8). The Morning Tiredness subscale accurately predicted a PDSS score in the 70th percentile (AUC?=?0.8). A cutoff score of 5 on the SDB subscale showed a sensitivity of 0.94 and a specificity of 0.76, correctly identifying 77 and 100 % of the clinical and community cohorts, respectively.

Conclusion

The PSSI Sleep Disordered Breathing subscale is a valid tool for screening SDB and daytime sleepiness in children aged 5–10 years.     

Genetics correlates with lung function and nocturnal ventilation in myotonic dystrophy

Background

Dystrophia myotonica (DM) is the most frequent adult-onset muscular dystrophy. Type 1 is caused by the cytosine–thymine–guanine (CTG) repeat expansion in the DM protein kinase gene. Respiratory muscle weakness and altered central ventilatory control lead to hypercapnia and lung volume restriction.

Purpose

This study aims to review the respiratory involvement in DM patients and study its relation with genetics.

Methods

Retrospective study of patients with DM referred for respiratory assessment was made. Noninvasive ventilation (NIV) was considered to daytime hypercapnia or symptoms of nocturnal hypoventilation.

Results

Forty-two consecutive patients (37.9?±?13.6 years) were evaluated. Mean CTG length was 642.8?±?439.2 repeats. In the first evaluation, mean forced vital capacity (FVC) was 74.4?±?20.2 %, maximal expiratory pressure (MEP) 35?±?16 %, maximal inspiratory pressure 52?±?23 %, peak cough flow (PCF) 327.3?±?97.7 L/min, arterial pressure of oxygen 79.7?±?11.3 mmHg, arterial pressure of carbon dioxide 45.5?±?6.2 mmHg, overnight minimal peripheral oxygen saturation (SpO₂) 79.6?±?11.6 %, and apnea–hypopnea index 13.9?±?9.9. CTG length was found to be related with MEP (r?=??0.67; p?=?0.001) and SpO₂ (r?=??0.37; p?=?0.039). NIV was started in 25 patients. Ventilated patients had lower FVC (2.19 to 3.21 L; p?<?0.001) and PCF (285.3 to 388.5 L/min; p?=?0.003) and more CTG repeats (826.6 to 388.5 repeats; p?=?0.02). NIV compliance was poor in seven patients (28 %) and related with hypercapnia (r?=?0.87; p?=?0.002) and inspiratory positive airway pressure setting (r?=?0.65; p?=?0.009). Ventilation improved symptoms and nocturnal hypoventilation. Comparing the first and last evaluations, only PCF was significantly lower (275.0 to 310.8 L/min; p?=?0.019).

Conclusions

Ventilatory insufficiency is very common in patients with DM and CTG length may be useful to predict it. Prolonged NIV improves symptoms, nocturnal hypoventilation and maintains daily blood gases. Routine evaluation of PCF should not be forgotten and assisted coughing training provided.     

The Impact of Obstructive Sleep Apnea and Nasal CPAP on Circulating Adiponectin Levels

Purpose

Although obstructive sleep apnea syndrome (OSAS) is known to be an important risk factor for cardiovascular diseases, the mechanism behind this association has not been fully elucidated. Transendothelial migration of monocytes mediated by adhesion molecules is a crucial step in the pathogenesis of atherosclerosis. We investigated the effect of hypoxic stress on plasma adiponectin and tumor necrosis factor-α (TNF-α) levels and whether adiponectin and TNF-α modulate adhesion molecules in patients with OSAS.

Methods

In 22 patients, plasma adiponectin and TNF-α levels and serum concentrations of soluble intercellular adhesion molecule-1 (sICAM-1) were determined early in the morning after polysomnography and after nasal continuous positive airway pressure (nCPAP) treatment.

Results

Plasma adiponectin levels were inversely correlated with the apnea–hypopnea index (AHI) (r = ?0.582, p < 0.005) and % time in SpO₂ <90 % (r = ?0.539, p < 0.01) but not with the body mass index (BMI). TNF-α levels were positively correlated with the AHI (r = 0.462, p < 0.05) and BMI (r = 0.452, p < 0.05). Serum sICAM-1 levels were inversely correlated with plasma adiponectin levels (r = ?0.476, p < 0.05) but not with TNF-α levels. Although plasma TNF-α levels decreased after overnight nCPAP treatment (p < 0.05), plasma adiponectin levels increased after long-term nCPAP (3 months) treatment (p < 0.02) in ten patients.

Conclusions

Our findings suggest that reduced adiponectin and elevated TNF-α levels in plasma are associated with OSAS-induced hypoxic stress. Decreased adiponectin levels are associated with sICAM-1 levels.     

Cerebrovascular pulsatility in patients with sleep-disordered breathing

Purpose

The aim of our study is to determine the association between the pulsatility index (PI), a surrogate of cerebral small vessel disease and sleep-disordered breathing (SDB).

Methods

We conducted a transcranial Doppler ultrasound (TCD) study of 19 consecutive patients free of stroke and cardiovascular disease, referred for the evaluation of SDB. TCD was performed by a certified technologist. Subsequent polysomnography was performed according to the practice parameters of the American Academy of Sleep Medicine. We evaluated the association between the apnea–hypopnea index (AHI), the oxygen nadir, the blood flow velocities, and the Gosling PI, for the middle cerebral artery. We performed Spearman's rank correlation and nonparametric regression to evaluate the relationship between AHI, oxygen levels, and the PI.

Results

Median age was 48 years (range 37–83), with 52 % male sex (n?=?10), and median BMI of 29.9 (range 25–40.4). The median AHI was 16.4 (0.2–69). The median PI was 0.97 (0.72–1.89) cm/s. The PI correlated with the AHI (rho?=?0.44; p?=?0.004) and with age (rho?=?0.57; p?=?0.001). Nonparametric regression adjusting for age showed a positive association between the AHI and the PI (standardized estimate?=?0.88; p?=?0.002). There was no relation between the oxygen nadir and the PI.

Conclusion

We observed increased PI in patients with SDB during wakefulness. The PI could potentially be an estimate of cerebral small vessel disease in patients with SDB and hence allow evaluating cerebral hemodynamics during wakefulness with a clinically relevant device.     

Urinary concentration of 8-isoprostane as marker of severity of pediatric OSAS

Background

F2-isoprostanes are considered to be a reliable standard biomarker of oxidative stress in vivo because they are not influenced by the intake of lipids in the diet, and they are chemically stable molecules and easily detected. This study aimed to test the hypothesis that 8-isoprostane level is a useful marker to valuate the severity of pediatric obstructive sleep apnea (OSA).

Methods

Sixty-five children with sleep-disordered breathing (SDB) (mean age 5.9?±?2.0 years; 63.1 % males) were recruited. The urine sample for the measurement of 8-isoprostane was collected the morning after the polysomnographic recording. Children were divided into two groups according to their apnea–hypopnea index (AHI).

Results

Urinary 8-isoprostane levels positively correlated with the sleep clinical record score (r?=?0.38, p?=?0.002) and AHI (r?=?0.24, p?=?0.05) and negatively correlated with age (r?=??0.36, p?=?0.003) and body surface area (r?=??0.38, p?=?0.002). Urinary 8-isoprostane levels were significantly higher in the group with AHI of ≥5 events (ev)/h than in the group with AHI of <5 ev/h (p?Conclusions Urinary 8-isoprostane may be used as a specific inflammatory marker to predict the severity of OSA; this method has the advantage of being noninvasive and easy to use in both compliant and noncompliant children.     

Glucocorticoid treatment impairs microvascular function in healthy men in association with its adverse effects on glucose metabolism and blood pressure: a randomised controlled trial

Aims/hypothesis

Glucocorticoids (GCs) are widely used anti-inflammatory agents that frequently induce side effects, including insulin resistance, diabetes and hypertension. Here, we investigated the contribution of microvascular dysfunction to the development of these adverse effects in healthy men.

Methods

In a randomised, placebo-controlled, dose–response intervention study, 32 healthy normoglycaemic men (age: 21?±?2 years; BMI: 21.9?±?1.7 kg/m²) were allocated to receive prednisolone 30 mg once daily (n?=?12), prednisolone 7.5 mg once daily (n?=?12) or placebo (n?=?8) for 2 weeks using block randomisation. A central office performed the treatment allocation, and medication was dispersed by the hospital pharmacy that was also blinded. Treatment allocation was kept in concealed envelopes. Participants, study personnel conducting the measures and assessing the outcome were blinded to group assignment. The study was conducted at a university hospital. Primary endpoint was prednisolone-induced changes in microvascular function, which was assessed by capillary microscopy. Insulin sensitivity was determined by hyperinsulinaemic–euglycaemic clamp and postprandial glycaemic excursions by standardised meal tests.

Results

Compared with placebo, prednisolone 7.5 mg and 30 mg decreased insulin-stimulated capillary recruitment by 9?±?4% and 17?±?3%, respectively (p?<?0.01). In addition, prednisolone 7.5 mg and 30 mg reduced insulin sensitivity (M value) by ?11.4?±?4.5 μmol kg^?1 min^?1 and ?25.1?±?4.1 μmol kg^?1 min^?1 (p?<?0.001) and increased postprandial glucose levels by 11?±?5% and 27?±?9% (p?<?0.001), respectively. Only high-dose prednisolone increased systolic blood pressure (6?±?1.2 mmHg, p?=?0.006). Prednisolone-induced changes in insulin-stimulated capillary recruitment were associated with insulin sensitivity (r?=?+0.76; p?<?0.001), postprandial glucose concentrations (r?=??0.52; p?<?0.03) and systolic blood pressure (r?=??0.62; p?<?0.001). Prednisolone increased resistin concentrations, which were negatively related to insulin-stimulated capillary recruitment (r?=??0.40; p?=?0.03). No effects were noted on adiponectin and leptin concentrations. Prednisolone treatment was well tolerated; none of the participants left the study.

Conclusions/interpretation

Prednisolone-induced impairment of insulin-stimulated capillary recruitment was paralleled by insulin resistance, increased postprandial glucose levels, hypertension and increased circulating resistin concentrations in healthy men. We propose that GC-induced impairments of microvascular function may contribute to the adverse effects of GC treatment on glucose metabolism and blood pressure.

Trial registration

isrctn.org ISRTCN 78149983

Funding

The study was funded by the Dutch Top Institute Pharma T1-106.     

A fatty meal aggravates apnea and increases sleep in patients with obstructive sleep apnea

Purpose

The purpose of this study was to investigate the role of a fatty meal before bedtime, on sleep characteristics and blood pressure in patients with obstructive sleep apnea (OSA).

Methods

Recently diagnosed, by full polysomnography (PSG), patients with OSA (n?=?19) were included. These underwent PSG for additional two consecutive nights. Two hours before the PSG examination, a ham and cheese sandwich of 360 kcal was served to all patients, at first night, while a fatty meal of 1,800 kcal was served before the second PSG examination. Comparisons were performed between the last two examinations in terms of PSG data and morning and night blood pressure measurements.

Results

After the fatty meal, a significant increase was observed in total sleep time (p?=?0.026) in the Apnea–Hypopnea Index (AHI) (p?=?0.015), as well as in the absolute number of obstructive and central apneas (p?=?0.032 and p?=?0.042, respectively) compared to the previous night. Conversely, distribution of sleep stages and indices of nocturnal hypoxia (average and minimum SpO₂ and sleep time with SpO₂?<?90 %) did not change significantly. Likewise, no significant change was observed in blood pressure measurements.

Conclusions

Fatty meal intake before sleep can increase AHI in OSA patients, although it does not affect sleep architecture or indices of hypoxia.     

Left ventricular subclinical dysfunction associated with myocardial deformation changes in obstructive sleep apnea patients estimated by real-time 3D speckle-tracking echocardiography

Background

Previous studies have demonstrated that patients with obstructive sleep apnea (OSA) may develop left ventricular (LV) diastolic dysfunction. We aimed to study whether OSA patients have LV regional systolic dysfunction with myocardial deformation changes, despite a normal LV ejection fraction, using real-time 3D speckle-tracking echocardiography (Rt3D-STE).

Methods

Seventy-eight patients with OSA and no comorbidities were studied. They were divided into the following three groups according to the apnea–hypopnea index (AHI): 5~15/h as group I (mild OSA, 26 cases), 15~30/h as group II (moderate OSA, 29 cases), and ≥30/h as group III (severe OSA, 23 cases). Thirty gender–age-matched normal subjects were included as controls. The parameters of LV diastolic function were acquired with traditional echocardiography. The LV myocardial deformation parameters were obtained, including the longitudinal (LS), circumferential (CS), radial (RS), and area (AS) strains, with Rt3D-STE.

Results

LV global systolic function was normal in all patients, but diastolic function was impaired in groups II and III (E/E′ was 9.6?±?2.8 and 10.4?±?2.5, respectively, p?<?0.0001). The global LS and AS were significantly reduced in groups II and III compared with the controls and group I (LS 15.9?±?1.4 % and 14.8?±?1.5 % vs 18.2?±?1.7 % and 17.8?±?1.5 %; AS 27.4?±?1.8 % and 24.9?±?2.3 % vs 33.4?±?2.2 % and 32.7?±?2.9 %, respectively, p?<?0.0001), but the global CS and RS were significantly reduced only in group III (17.3?±?1.4 % and 43.1?±?6.5 % vs 19.6?±?1.6 % and 55.4?±?4.0 %, respectively, <0.0001). The severity of OSA was significantly associated with the LV global AS value (r?=??0.80, p?<?0.0001), LS (r?=??0.64, p?<?0.0001), CS (r?=??0.51, p?<?0.0001), and RS (r?=??0.62, p?<?0.0001).

Conclusions

Patients with moderate and severe OSA tended to have both LV diastolic dysfunction and abnormalities in regional systolic function with myocardial deformation changes, in spite of the normal LV ejection fraction. Myocardial strains of the LV were negatively correlated with the AHI. Rt-3DST had important clinical significance in the early evaluation of cardiac dysfunction in OSA patients.

     

Normal values and pressure morphology for three-dimensional high-resolution anorectal manometry of asymptomatic adults: a study in 110 subjects

Objectives

The purpose of this study is to evaluate normal values and pressure morphology of three-dimensional high-resolution anorectal manometry (3D-HRM) in asymptomatic volunteers and to determine the relationship between objective measurable values, gender, and age.

Patients and methods

Anorectal pressures and rectal sensation were evaluated in 110 asymptomatic volunteers (46 females and 64 males) ranging in age from 18 to 80 years (median age, 52 years) in left lateral position by three-dimensional high-resolution manometry.

Results

Maximum squeeze pressure, residual anal pressure, and intrarectal pressure were significantly higher in males compared to females (p?<?0.05 each). Duration of sustained squeeze was significantly lower in males compared to females (p?<?0.05). Maximum resting pressure, mean resting pressure, and maximum squeeze pressure were inversely correlated (r?=??0.310, p?<?0.01, r?=??0.276, p?<?0.01, and r?=??0.198, p?<?0.05) with age. The value of rectoanal pressure differential was ?13.1?±?5.8 mmHg which was negative during defecation. Overall variation coefficient in anorectal pressures ranged between 0.21 and 0.34.

Conclusion

This study establishes normal values for anorectal pressure by 3D-HRM in asymptomatic volunteers. There are significant gender differences concerning squeeze patterns. Increasing age is associated with lower maximum resting pressure, mean resting pressure, and maximum squeeze pressure. Normal characteristic pressure morphology of anorectum can be obtained at rest, during squeeze, and bear down as in defecation by 3D-HRM.     

Intensified insulin treatment is associated with improvement in skin microcirculation and ischaemic foot ulcer in patients with type 1 diabetes mellitus: a long-term follow-up study

Aims/hypothesis

We investigated skin microcirculation and its association with HbA_1c and the incidence of ischaemic foot ulcer in patients with type 1 diabetes formerly randomised (1982–1984) to intensified conventional treatment (ICT) or standard treatment (ST) with insulin for a mean of 7.5 years.

Methods

We re-determined the skin microcirculation of 72 patients (ICT 35 vs ST 37) from the original Stockholm Diabetes Intervention Study with iontophoresis topically applied with the following vasoactive stimuli: acetylcholine (ACh) (endothelial-dependent vasodilatation), sodium nitroprusside (SNP) (endothelial-independent vasodilatation), and capsaicin (C-nociceptive-dependent vasodilatation). HbA_1c levels (mean of 14 values/patient) were prospectively collected between 1990 and 1995 and tested for association with skin microcirculation. The patients were followed until first hospitalisation for an ischaemic foot ulcer or until 2011.

Results

During the median 28 years of follow-up, three patients developed ischaemic foot ulcers in the ICT group compared with ten in the ST group (logrank, p?=?0.035). At the time of iontophoresis, HbA_1c was lower in the ICT group (median 57 mmol/mol [minimum–maximum 40–79 mmol/mol]) compared with the ST group (68 mmol/mol [41–96 mmol/mol], p?<?0.01) (DCCT: ICT 7.4% [5.8–9.4%] vs ST 8.4% [5.9–10.9%]). Stimulated blood flow was higher in the ICT vs ST group with significantly increased perfusion units (PU) for: ACh (8.1 PU [4.6–24.7 PU] vs 5.3 PU [1.7–21.4 PU], p?<?0.01); SNP (8.1 PU [2.2–20.1 PU] vs 5.6 PU [2.3–19.2 PU], p?=?0.03); and capsaicin (5.0 PU [1.7–22.9 PU] vs 3.4 PU [1.5–8.4 PU], p?<?0.01). HbA_1c was associated with vasodilatation induced by ACh (b?=??0.02, p?<?0.01) and capsaicin (b?=??0.02, p?=?0.03). HbA_1c was independently associated with ACh (b?=??1.48, p?<?0.01) and capsaicin-induced vasodilatation (b?=??1.45, p?<?0.01).

Conclusions/interpretation

Improved glycaemic control in patients with type 1 diabetes is associated with an improvement in skin microcirculation and with a lower incidence of ischaemic foot ulcers. Trial registration: ClinicalTrials.gov NCT01957930     

Effect of transnasal insufflation on sleep disordered breathing in acute stroke: a preliminary study

Background and Purpose

Sleep disordered breathing (SDB) is frequent in acute stroke patients and is associated with early neurologic worsening and poor outcome. Although continuous positive airway pressure (CPAP) effectively treats SDB, compliance is low. The objective of the present study was to assess the tolerance and the efficacy of a continuous high-flow-rate air administered through an open nasal cannula (transnasal insufflation, TNI), a less-intrusive method, to treat SDB in acute stroke patients.

Methods

Ten patients (age, 56.8?±?10.7?years), with SDB ranging from moderate to severe (apnea?Chypopnea index, AHI, >15/h of sleep) and on a standard sleep study at a mean of 4.8?±?3.7?days after ischemic stroke (range, 1?C15?days), were selected. The night after, they underwent a second sleep study while receiving TNI (18?L/min).

Results

TNI was well tolerated by all patients. For the entire group, TNI decreased the AHI from 40.4?±?25.7 to 30.8?±?25.7/h (p?=?0.001) and the oxygen desaturation index >3% from 40.7?±?28.4 to 31?±?22.5/h (p?=?0.02). All participants except one showed a decrease in AHI. The percentage of slow-wave sleep significantly increased with TNI from 16.7?±?8.2% to 22.3?±?7.4% (p?=?0.01). There was also a trend toward a reduction in markers of sleep disruption (number of awakenings, arousal index).

Conclusions

TNI improves SDB indices, and possibly sleep parameters, in stroke patients. Although these changes are modest, our findings suggest that TNI is a viable treatment alternative to CPAP in patients with SDB in the acute phase of ischemic stroke.     

Treatment of obstructive sleep apnea using a custom-made titratable duobloc oral appliance: a prospective clinical study

Purpose

This prospective clinical study investigates the efficacy of a specific custom-made titratable mandibular advancement device (MAD) for the treatment of obstructive sleep apnea (OSA). This MAD has attachments in the frontal teeth area that allow for progressive titration of the mandible.

Methods

Sixty-one adult OSA patients were included (age, 46.7?±?9.0 years; male/female ratio, 45/16; apnea–hypopnea index (AHI), 23.2?±?15.4 events/h sleep; body mass index, 27.9?±?4.1 kg/m²). After an adaptation period, titration started based on a protocol of symptomatic benefit or upon reaching the physiological limits of protrusion. As a primary outcome, treatment response was defined as an objective reduction in AHI following MAD treatment of ≥50 % compared to baseline, and treatment success as a reduction in AHI with MAD to less than 5 and 10 events/h sleep. Compliance failure was defined as an inability to continue treatment.

Results

A statistically significant decrease was observed in AHI, from 23.4?±?15.7 at baseline to 8.9?±?8.6 events/h with MAD (p?<?0.01). Treatment response was achieved in 42 out of 61 patients (68.8 %), whereas 42.6 % met criteria of AHI?<?5 and 63.9 % achieved an AHI?<?10 events/h sleep, respectively. Four patients (6.6 %) were considered as “compliance failures.”

Conclusions

The present study has evaluated the efficacy of a specific custom-made titratable MAD in terms of sleep apnea reduction.     

Respiratory effort-related arousals contribute to sympathetic modulation of heart rate variability

Purpose

Sympathetic activation induced by sleep-disordered breathing may contribute to cardiovascular morbidity. However, the apnea–hypopnea index (AHI) excludes respiratory effort-related arousals (RERAs) associated with inspiratory flow limitation without oxygen desaturation. We sought to determine whether RERAs are associated with sympathetic activation.

Methods

Twenty-five adults (12 males, 13 females) with AHI?<?10/h and RERA index >5/h were included in this study. Power spectral density analysis was performed on two non-contiguous 10-min segments containing inspiratory flow limitation and arrhythmia-free electrocardiogram during N2 sleep. One segment contained RERA; the other did not, NO-RERA. Spectral power was described in a low-frequency domain (LF; 0.04–0.15 Hz), primarily sympathetic modulation, and a high frequency domain (HF; 0.15–0.4 Hz), parasympathetic modulation.

Results

Analyses of LF and HF powers were made using normalized and absolute values. LF power was greater during RERA compared to NO-RERA (50.3 vs. 30.1 %, p?<?0.001) whereas HF power was greater during NO-RERA compared to RERA (69.9 vs. 49.7 %, p?<?0.001). The LF/HF ratio was greater during RERA than NO-RERA (1.01 vs. 0.43, p?<?0.001). Gender differences emerged using absolute values of power: The percentage increase in LF power during RERA relative to NO-RERA was significantly greater for females than males, 247.6 vs. 31.9 %, respectively (p?<?0.02).

Conclusions

RERAs are associated with a marked increase in cardiac sympathetic modulation, especially in females. Patients with a high RERA index, even in the setting of a low or normal AHI, may be exposed to elevated sympathetic tone during sleep.     

Reverse atrial electrical remodelling induced by continuous positive airway pressure in patients with severe obstructive sleep apnoea

Background

Obstructive sleep apnoea (OSA) is associated with cardiovascular morbidity and mortality, including atrial arrhythmias. Continuous positive airway pressure (CPAP) is the gold standard treatment for OSA; its impact on atrial electrical remodelling has not been fully investigated. Signal-averaged p-wave (SAPW) duration is an accepted marker for atrial electrical remodelling.

Objective

The objective of this study is to determine whether CPAP induces reverse atrial electrical remodelling in patients with severe OSA.

Methods

Consecutive patients attending the Sleep Disorder Clinic at Kingston General Hospital underwent full polysomnography. OSA-negative controls and severe OSA were defined as apnoea–hypopnea index (AHI)?<?5 events/hour and AHI?≥?30 events/hour, respectively. SAPW duration was determined at baseline and after 4–6 weeks of CPAP in severe OSA patients or without intervention controls.

Results

Nineteen severe OSA patients and 10 controls were included in the analysis. Mean AHI and minimum oxygen saturation were 41.4?±?10.1 events/hour and 80.5?±?6.5 % in severe OSA patients and 2.8?±?1.2 events/hour and 91.4?±?2.1 % in controls. At baseline, severe OSA patients had a greater SAPW duration than controls (131.9?±?10.4 vs 122.8?±?10.5 ms; p?=?0.02). After CPAP, there was a significant reduction of SAPW duration in severe OSA patients (131.9?±?10.4 to 126.2?±?8.8 ms; p?<?0.001), while SAPW duration did not change after 4–6 weeks in controls.

Conclusion

CPAP induced reverse atrial electrical remodelling in patients with severe OSA as represented by a significant reduction in SAPW duration.     

Levels of thioredoxin are related to the severity of obstructive sleep apnea: based on oxidative stress concept

Background

Oxidative stress is a typical feature of obstructive sleep apnea (OSA). Thioredoxin (TRX), as one of the oxidative stress biomarkers, is a potent protein disulfide reductase in antioxidant defense. Our study is designed to test whether thioredoxin could assess the severity of OSA.

Methods

Sixty-three adults suspected of having OSA were included in this study and were divided into four groups based on the results of polysomnography (PSG): control, mild, moderate, and severe. Subjects with chronic medical diseases (with the exception of essential hypertension) or taking any antioxidant medication were excluded. Blood samples were obtained within an hour after the overnight PSG test. Plasma TRX levels were detected by enzyme-linked immunosorbent assay.

Results

The plasma TRX level in severe group was obviously increased (8.62?±?2.14, 13.33?±?5.60, 14.71?±?5.53, and 16.10?±?7.34 ng/ml; p?<?0.05). The TRX positively related to AHI (r?=?0.313; p?<?0.05), while negatively related to the lowest O₂ saturation (r?=?0.266; p?<?0.037). The OSA patients associated with hypertension showed elevated TRX level (17.70?±?6.98 vs. 13.43?±?5.83 ng/ml; t?=?2.434, p?<?0.018). The cutoff value of TRX for identifying OSA was 9.39 ng/ml (sensitivity 91 %, specificity 78 %), and its cutoff value for differentiating moderate–severe OSA from mild OSA was 11.79 ng/ml (sensitivity 75 %, specificity 65 %).

Conclusion

These results suggest that plasma TRX level is associated with the severity of OSA. Therefore, TRX may be used as a severity indicator of OSA.     

Effects of twin block appliance on obstructive sleep apnea in children: a preliminary study

Background

Oral appliances are increasingly advocated as a treatment option for obstructive sleep apnea (OSA). However, it is not clear how the different designs influence treatment efficacy in children. The aim of this study was to investigate the effects of twin block (TB) appliance on children with OSA and mandibular retrognathia.

Methods

A total of 46 children (31 males, 15 females, aged 9.7?±?1.5 years, BMI: 18.1?±?1.04 kg/m²) diagnosed with mandibular retrognathia and OSA by polysomnography (PSG) and with no obesity or adenotonsillar hypertrophy were recruited for the study. Patients in the treatment group were instructed to wear the twin block oral appliance full time for an average of 10.8 months. The efficacy of treatment was determined by monitoring the PSG and cephalometric changes before and after appliance removal. Data were analyzed using paired t test.

Results

Results showed an improvement in patient's facial profile after treatment with the TB appliance. The average AHI index decreased from 14.08?±?4.25 to 3.39?±?1.86 (p?<?0.01), and the lowest SaO₂ increased from 77.78?±?3.38 to 93.63?±?2.66 (p?<?0.01). Cephalometric measurements showed a significant increase in the superior posterior airway space, middle airway space, SNB angle and facial convexity which indicate an enhancement in mandibular growth, and reduction in the soft palate length.

Conclusions

This preliminary study suggests that twin block appliance may improve the patient's facial profile and OSA symptoms in a group of carefully selected children presented with both OSA and mandibular retrognathia symptoms.     

CPAP therapy prevents increase in blood pressure after upper airway surgery for obstructive sleep apnoea

Objective

The aim of this study was to investigate the efficacy of continuous positive airway pressure (CPAP) therapy following uvulopalatopharyngoplasty (UPPP) to prevent blood pressure (BP) elevation during sleep.

Methods

Sixteen normotensive patients with OSA were subjected to UPPP with or without septoplasty. These patients were instrumented for 24 h of ambulatory BP recording, polysomnography, nocturnal urinary catecholamine and pain evaluation using a visual analogue scale in the day prior to surgery (D?1), following the surgery (D+1) and 30 days later (D+30). For the D+1, the patients were divided into two groups: the without CPAP therapy group and the with CPAP therapy group.

Results

The apnoea–hypopnoea index (AHI) significantly increased in the patients without CPAP therapy compared with the D?1 (74?±?23 vs. 35?±?6 times/h, p?<?0.05), and in the CPAP group, there was a significant reduction in the average AHI value to 14?±?6 times/h, p?<?0.01. During D+1, we observed an increase in the nocturnal systolic BP (10 %), diastolic BP (12 %) and heart rate (14 %) in the group without CPAP. These metrics were re-established in the CPAP group to values that were similar to those that were observed on the D?1. The absence of nocturnal dipping in the group without CPAP was followed by a significant increase in nocturnal norepinephrine (42?±?12 μg/l/12 h) and epinephrine (8?±?2 μg/l/12 h) levels compared with the D?1 (norepinephrine 17?±?3; epinephrine 2?±?0.3 μg/l/12 h, p?<?0.001). In the patients who used the CPAP treatment, the nocturnal catecholamine levels were similar to D?1. The effectiveness of intravenous analgesic therapy was verified by a significant decrease in the pain scores in patients both with and without CPAP therapy.

Conclusion

These data confirm an increase in the AHI on the night following UPPP with or without septoplasty. This increase promotes an absence of nocturnal dipping and a significant increase in urinary catecholamine levels. CPAP therapy was effective to prevent the transitory increase in BP.