Nasal continuous positive airway pressure: influence on digital volume pulse in obstructive sleep apnoea patients

Obstructive sleep apnoea (OSA) is linked to increased cardiovascular risk. This risk can be reduced by nasal continuous positive airway pressure (nCPAP) treatment. As OSA is associated with an increase of several vasoconstrictive factors, we investigated whether nCPAP influences the digital volume pulse wave. We performed digital photoplethysmography during sleep at night in 94 consecutive patients who underwent polysomnography and 29 patients treated with nCPAP. Digital volume pulse waves were obtained independently of an investigator and were quantified using an algorithm for continuous automated analysis. In patients with OSA and an apnoea/hypopnoea index (AHI) of >10 events · h(-1), a significant vasoconstriction was observed during the night (p<0.0001 by Friedman's test). A significant positive correlation existed between vasoconstriction and AHI (Spearman correlation, r = 0.27; p<0.01; n = 94) and the arousal index (Spearman correlation, r = 0.21; p < 0.05; n = 94). After 6 months of nCPAP treatment, the AHI was significantly reduced from 27 ± 3 events · h(-1) to 4 ± 2 events · h(-1) (each n = 29; p<0.001) and vasoconstriction during the night was significantly reduced from 10 ± 3% to 3 ± 1% (p<0.01). We show changes in the reflective index during the night consistent with vasoconstriction in patients with OSA, which are significantly reduced after 6 months of nCPAP treatment.     

Residual sleep-disordered breathing during autotitrating continuous positive airway pressure therapy

Obstructive sleep apnoea (OSA) is often treated with autotitrating continuous positive airway pressure (autoCPAP) devices. Clinical and bench tests of these devices have suggested performance limitations. These studies do not indicate whether this is a failure to detect or a failure to respond to airway obstruction. In this randomised, crossover trial, 34 patients with moderate-to-severe OSA underwent polysomnography on two laboratory visits. The autoCPAP device was randomly set to a fixed subtherapeutic pressure (detection assessment) or autotitrating mode (response assessment). Airflow was measured both from the autoCPAP (autoCPAP flow) and directly from the nasal mask, and recorded on polysomnography. Apnoea/hypopnoea indices (AHIs) measured at the two sites and from the autoCPAP download report were compared. Regarding detection, the AHI measured from the nasal mask showed good agreement with the autoCPAP flow AHI, but agreement was lower with the autoCPAP report AHI. In autotitrating mode, there was significant misclassification of those with and without OSA (AHI ≥ 10 events · h(-1)) on the autoCPAP report. Regarding response, residual OSA (AHI ≥ 10 events · h(-1)) was still evident in 24% of patients during autotitration. In some patients, autoCPAP fails to detect and/or respond to sleep apnoea. Clinicians should consider limitations of each device and use caution when using autoCPAP report statistics to verify effective treatment.     

Effect of Mediterranean diet versus prudent diet combined with physical activity on OSAS: a randomised trial

We aimed to evaluate the effect of the Mediterranean diet (MD) compared with a prudent diet (PD) combined with physical activity on obese obstructive sleep apnoea syndrome (OSAS) patients who were treated with continuous positive airway pressure. 900 patients were evaluated and 40 obese patients (body mass index ≥ 30.0 kg · m(-2)) who met the inclusion criteria, with moderate-to-severe OSAS (apnoea-hypopnoea index (AHI) >15 events · h(-1) and Epworth Sleepiness Scale score >10) based on overnight attended polysomnography, were included in the study. After randomisation, 20 patients followed the MD and 20 a PD for a 6-month period. All patients were counselled to increase their physical activity. Concerning sleep parameters, only AHI during rapid eye movement (REM) sleep was reduced to a statistically significant degree, by mean ± SD 18.4 ± 17.6 events · h(-1) in the MD group and by 2.6 ± 23.7 events · h(-1) in the PD group (p<0.05). The MD group also showed a greater reduction in waist circumference (WC) (-8.7 ± 3.6 cm), WC/height ratio (-0.04 ± 0.02 cm · m(-1)) and WC/hip ratio (-0.04 ± 0.03 cm · cm(-1)), compared with the other group (-2.6 ± 1.7 events · h(-1), -5.7 ± 3.8 cm, -0.03 ± 0.02 cm · m(-1) and 0.02 ± 0.02 cm · cm(-1), respectively; p<0.05). Our results showed that the MD combined with physical activity for a 6-month period was effective in reducing the AHI during REM sleep without any statistically significant effect in the other sleep parameters, compared with a PD in obese adults with moderate-to-severe OSAS.     

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.     

The effect of 1 week of continuous positive airway pressure treatment in obstructive sleep apnea patients with concomitant gastroesophageal reflux

STUDY OBJECTIVES: Patients with obstructive sleep apnea (OSA) have a very high incidence of gastroesophageal reflux (GER). Previous studies have shown that the use of continuous positive airway pressure (CPAP) reduces the frequency of reflux events, but these studies only assessed the effect of a single night of treatment. The aim of this study was to assess the effect of 1 week of CPAP treatment on reflux in patients with OSA and GER. DESIGN: Sixteen patients with OSA and GER were recruited. Polysomnography followed by 24-h, continuous esophageal pH monitoring were performed at baseline. Patients with an apnea-hypopnea index (AHI) > 20/h and 24-h acid contact time (ACT) of at least 6% were included. As part of the polysomnography-qualifying evaluation, all patients underwent CPAP titration to reduce the AHI to < 10/h. Patients were then sent home receiving nasal CPAP for 1 week; after 1 week, esophageal pH monitoring was repeated while receiving CPAP. MEASUREMENTS AND RESULTS: The AHI fell from 63.3 +/- 38.5 to 3.2 +/- 2.2/h (mean +/- SD) [p < 0.001]. Total ACT fell from 13.9 +/- 11.6 to 5.6 +/- 2.7% (p < 0.001). The upright ACT was reduced from 12.4 +/- 6.8 to 6.8 +/- 3.8% (p = 0.01), and the supine (during the sleeping interval) ACT was reduced from 16.3 +/- 18.8 to 3.8 +/- 7.6% (p < 0.01). Eighty-one percent of the patients had a reduction in supine ACT to within the normal range (< 4%). CONCLUSIONS: In OSA patients with significant heartburn complaints, CPAP would appear to be an efficacious approach to the treatment of both disorders.     

Visual Improvement following Continuous Positive Airway Pressure Therapy in Diabetic Subjects with Clinically Significant Macular Oedema and Obstructive Sleep Apnoea: Proof of Principle Study

Background: Diabetic retinopathy and diabetic macular oedema are more prevalent in patients with coexistent obstructive sleep apnoea (OSA). Objectives: We assessed if treatment of OSA with continuous positive airway pressure (CPAP) might improve visual acuity (VA). Methods: A total of 35 patients with clinically significant macular oedema (CSMO) and OSA [oxygen desaturation index (ODI) ≥10 or apnoea-hypopnoea index (AHI) ≥15] were identified and agreed to be studied. VA (expressed as the logarithm of the minimum angle of resolution, logMAR), macular thickness, fundal photographs, glycosylated haemoglobin (HbA1c) and rhodopsin mRNA were measured twice at baseline and at 3 and 6 months post-CPAP. Fluorescein angiography and the Epworth Sleepiness Scale (ESS) were obtained once at baseline and at 6 months. Results: Three patients withdrew before the first trial visit. Thus, a total of 32 patients (17 males) entered the study, and 4 subsequently withdrew; thus 28 completed 6 months of follow-up. Baseline characteristics of the subjects were as follows [mean (SD or inter-quartile range)]: age 66.2 (7.1) years, body mass index 31.7 (6.3), HbA1c 7.4% (1.44) [57.1 (15.7) mmol/mol], AHI 16.5 (11-25), ODI 16.0 (12-25), ESS 6.5 (4.0-12.0) and duration of diabetes 9.5 years (5.0-16.5). Participants were divided into 13 high and 15 low CPAP compliers (≥ and <2.5 h/night over the 6 months, respectively). At 6 months, the adjusted treatment effect on VA of high compliance versus low compliance was 0.11 (95% confidence interval 0.21 to -0.002; p = 0.047), equivalent to a one-line improvement on the logMAR chart. There was no significant improvement in macular oedema or fundal photographs. Conclusions: This hypothesis-generating, uncontrolled study suggests that ≥2.5 h/night CPAP usage over 6 months in individuals with CSMO and OSA may be associated with improvement in VA. This provides justification for a randomised controlled trial of CPAP therapy in such patients.     

Prevalence of sleep-disordered breathing and continuous positive airway pressure compliance: results in chinese patients with first-ever ischemic stroke

OBJECTIVE: To assess the prevalence of sleep-disordered breathing (SDB), continuous positive airway pressure (CPAP) acceptance, and CPAP compliance in patients who have experienced ischemic stroke. DESIGN: A case-controlled study. SETTING: A university hospital. MEASUREMENTS AND RESULTS: We recruited 23 women and 28 men, who were admitted to the hospital within 4 days of stroke onset, with a mean (+/- SD) age of 64.2 +/- 13.0 years and a body mass index (BMI) of 24.3 +/- 4.4 kg/m(2) for this study. Twenty-seven patients (53%) and 9 patients (17.6%), respectively, reported a history of snoring and severe daytime sleepiness prior to experiencing a stroke, while the mean Epworth sleepiness scale score was 6.8 +/- 3.6. Polysomnography revealed 34 patients (67%) with an apnea-hypopnea index (AHI) of > or = 10 events per hour, 31 patients (61%) with an AHI of > or = 15 events per hour, and 25 patients (49%) with an AHI of > or = 20 events per hour. Significant obstructive SDB, defined as an AHI of > or = 20/h, was more prevalent in ischemic stroke patients than in control subjects (49% vs 24%, respectively; p = 0.04) and was associated with a higher BMI (p = 0.046). Among the 34 patients with an AHI of > or = 10/h, CPAP titration was tolerated by 16 patients, but only 4 patients who had typical sleep apnea features proceeded to home CPAP treatment with objective compliance over a period of 3 months of 2.5 +/- 0.6 h per night. A subgroup of 20 patients not receiving CPAP showed partial spontaneous improvement of SDB at 1 month (baseline AHI, 32.3 +/- 17.6 events per hour; AHI at 1 month, 23.0 +/- 18.8 events per hour; p = 0.01) with a trend toward improvement for the obstructive but no significant change for the central events, whereas no improvement in AHI was noted for the four patients receiving CPAP. CONCLUSION: There is a high prevalence of obstructive SDB in patients who have experienced acute ischemic stroke, which, in many cases, is different from classic obstructive sleep apnea syndrome, and this is reflected by the lack of significant sleepiness, poor CPAP acceptance, and partial spontaneous improvement at 1 month.     

The relation of serum 25-hydroxyvitamin-D levels with severity of obstructive sleep apnea and glucose metabolism abnormalities

Obstructive sleep apnea (OSA) and 25-hydroxyvitamin-D? (25-OH-D) deficiency are two separate disorders associating with obesity, inflammation, and impaired glucose metabolism. We aimed to investigate the vitamin D status of OSA patients regarding to potential links between lower vitamin D levels and abnormal glucose metabolism, which is one of the main adverse outcomes of OSA. Study group is composed of 190 non-diabetic subjects who were suspected of having OSA. Subjects undergone polysomnography and were grouped due to apnea-hypopnea indices (AHI) as controls (AHI < 5, n = 47), mild OSA (5 ≤ AHI < 15, n = 46), moderate OSA (15 ≤ AHI < 30, n = 47), and severe OSA (AHI ≥ 30, n = 50). Serum 25-OH-D, HbA?c, insulin levels were measured and 75-g oral glucose tolerance test was performed. Serum 25-OH-D level (ng/ml) of OSA patients were lower than control subjects (17.4 ± 6.9 vs. 19.9 ± 7.8), and decrement was parallel to severity of OSA; as 18.2 ± 6.4 (5 ≤ AHI < 15), 17.5 ± 7.4 (15 ≤ AHI < 30), and 16.3 ± 6.9 (AHI > 30), respectively (P = 0.097, r = -0.13). However, severe female OSA patients had significantly lower 25-OH-D levels (11.55 ng/ml), while control males had the highest mean value (21.7 ng/ml) (P < 0.001). Frequency of insulin resistance (IR) was 48%, prediabetes 41%, diabetes 16% in OSA patients. Mean 25-OH-D level of insulin resistant subjects (HOMA-IR ≥ 2.7, n = 77, AHI = 35.5) was lower than non-insulin resistant subjects (HOMA-IR < 2.7, n = 113, AHI = 19.8) as 16.18 ± 7.81 versus 19.2 ± 6.6, respectively (P = 0.004). 25-OH-D level of 91 non-diabetic subjects (n = 91, AHI = 19.7) was 19.5 ± 7.4, prediabetics (n = 75, AHI = 28.7) was 17.45 ± 6.9, and diabetics (n = 24, AHI = 46.3) was 13.8 ± 5.3 (P = 0.02). We showed that subjects with more severe OSA indices (AHI ≥ 15) tended to present lower vitamin D levels correlated to increased prevalence of IR, prediabetes, and diabetes. Vitamin D deficiency may play a role and/or worsen OSA's adverse outcomes on glucose metabolism. OSA patients may be considered for supplementation treatment which was shown to ameliorate abnormal glucose metabolism and inflammation.     

The effects of continuous positive airway pressure therapy on mean platelet volume in patients with obstructive sleep apnea

Previous studies have reported increased platelet activation and aggregation in patients with obstructive sleep apnea (OSA). Continuous positive airway pressure (CPAP) treatment has been shown to decrease platelet activation. We aimed to study the effects of nasal CPAP therapy has on MPV values in patients with severe OSA. Thirty-one patients (21 men; mean age 53.8?±?9.2 years) with severe OSA (AHI?>?30 events/hour) constituted the study group. An age, gender and body mass index (BMI) matched control group was composed 25 subjects (14 men; mean age 49.6?±?8.5 years) without OSA (AHI?相似文献   

Long-term Effect of CPAP Treatment on Cardiovascular Events in Patients With Resistant Hypertension and Sleep Apnea. Data From the HIPARCO-2 Study

BackgroundThere is some controversy about the effect of continuous positive airway pressure (CPAP) on the incidence of cardiovascular events (CVE). However, the incidence of CVE among patients with both obstructive sleep apnea (OSA) ans resistant hypertension (HR) has not been evaluated. Our objective was to analyze the long-term effect of CPAP treatment in patients with RH and OSA on the incidence of CVE.MethodsMulti-center, observational and prospective study of patients with moderate-severe OSA and RH. All the patients were followed up every 3–6 months and the CVE incidence was measured. Patients adherent to CPAP (at least 4 h/day) were compared with those with not adherent or those who had not been prescribed CPAP.ResultsValid data were obtained from 163 patients with 64 CVE incidents. Treatment with CPAP was offered to 82%. After 58 months of follow-up, 58.3% of patients were adherent to CPAP. Patients not adherent to CPAP presented a non-significant increase in the total CVE incidence (HR:1.6; 95%CI: 0.96–2.7; p = 0.07). A sensitivity analysis showed that patients not adherent to CPAP had a significant increase in the incidence of cerebrovascular events (HR: 3.1; CI95%: 1.07–15.1; p = 0.041) and hypertensive crises (HR: 5.1; CI95%: 2.2–11.6; p = 0.006), but the trend went in the opposite direction with respect to coronary events (HR: 0.22; CI95%: 0.05–1.02; p = 0.053).ConclusionsIn patients with RH and moderate-severe OSA, an uneffective treatment with CPAP showed a trend toward an increase in the incidence of CVE (particularly neurovascular events and hypertensive crises) without any changes with respect to coronary events.     

The role of the expiratory phase in obstructive sleep apnoea.

The role of the expiratory phase in obstructive sleep apnoea (OSA) is not well known. The aim of our study was to verify the contribution of expiratory narrowing to apnoea in a group of OSA patients by evaluating the effects of short-term treatment with continuous positive airway pressure (CPAP), intermittent positive pressure ventilation (IPPV) and bi-level positive airway pressure (BIPAP). We studied a selected group of 10 OSA patients whose therapeutic pressure level of CPAP was at least 10 cm H2O. During CPAP therapy the mean apnoea/hypopnoea index (AHI) and oxyhaemoglobin desaturation index (ODI) decreased from 64.8 to 6.3 (P < 0.001) and from 58.5 to 6.1 (P < 0.001), respectively and mean nadir SAO2 increased from 62.0 to 91.6 (P < 0.001). None of the patients reached optimal setting (elimination of snoring, reduction of apnoeas and non-apnoeic desaturation events at least to 15 or less per hour of sleep and maintenance of oxygen saturation approximately 90%) during IPPV and two patients did not tolerate final IPAP pressure levels. When a critical level of EPAP (BIPAP) was applied in the same night to these patients, optimal setting was reached in all subjects. During BIPAP, mean AHI decreased from 64.8 to 7.4 (P < 0.001); ODI decreased from 58.5 to 7.6 (P < 0.001) and nadir SAO2 increased from 62.0 to 91.2 (P < 0.001). Our study confirms the essential role of a critical level of EPAP in successful ventilatory treatment in OSA, thereby indicating, in agreement with few previous studies, the critical role of end of expiratory occlusion in OSA pathogenesis.     

Cephalometric abnormalities in non-obese and obese patients with obstructive sleep apnoea.

The aim of this work was to comprehensively evaluate the cephalometric features in Japanese patients with obstructive sleep apnoea (OSA) and to elucidate the relationship between cephalometric variables and severity of apnoea. Forty-eight cephalometric variables were measured in 37 healthy males and 114 male OSA patients, who were classed into 54 non-obese (body mass index (BMI) <27 kg x m(-2), apnoea-hypopnoea index (AHI)=25.3+/-16.1 events x h(-1)) and 60 obese (BMI > or = 27 kg x m(-2), AHI=45.6+/-28.0 events h(-1)) groups. Diagnostic polysomnography was carried out in all of the OSA patients and in 19 of the normal controls. The non-obese OSA patients showed several cephalometric defects compared with their BMI-matched normal controls: 1) decreased facial A-P distance at cranial base, maxilla and mandible levels and decreased bony pharynx width; 2) enlarged tongue and inferior shift of the tongue volume; 3) enlarged soft palate; 4) inferiorly positioned hyoid bone; and 5) decreased upper airway width at four different levels. More extensive and severe soft tissue abnormalities with a few defects in craniofacial bony structures were found in the obese OSA group. For the non-obese OSA group, the stepwise regression model on AHI was significant with two bony structure variables as determinants: anterior cranial base length (S-N) and mandibular length (Me-Go). Although the regression model retained only linear distance between anterior vertebra and hyoid bone (H-VL) as an explainable determinant for AHI in the obese OSA group, H-VL was significantly correlated with soft tissue measurements such as overall tongue area (Ton), inferior tongue area (Ton2) and pharyngeal airway length (PNS-V). In conclusion, Japanese obstructive sleep apnoea patients have a series of cephalometric abnormalities similar to those described in Caucasian patients, and that the aetiology of obstructive sleep apnoea in obese patients may be different from that in non-obese patients. In obese patients, upper airway soft tissue enlargement may play a more important role in the development of obstructive sleep apnoea, whereas in non-obese patients, bony structure discrepancies may be the dominant contributing factors for obstructive sleep apnoea.     

Obesity hypoventilation syndrome: hypoxemia during continuous positive airway pressure

BACKGROUND: Polysomnography findings between matched groups with obstructive sleep apnea (OSA) and OSA plus obesity-hypoventilation syndrome (OHS) before and after continuous positive airway pressure (CPAP), particularly in the extremely severe obese (body mass index [BMI] >or= 50 kg/m2), are unclear. DESIGN: Prospective study of subjects (BMI >or= 50 kg/m2) undergoing diagnostic polysomnography. Subjects with an apnea-hypopnea index (AHI) >or= 15/h underwent a second polysomnography with CPAP. The effect of 1 night of CPAP on sleep architecture, AHI, arousal indexes, and nocturnal oxygenation was assessed. OHS was defined as those subjects with obesity, PaCo2 > 45 mm Hg, and PaO2 < 70 mm Hg in the absence of lung disease. RESULTS: Twenty-three subjects with moderate-to-severe OSA and 23 subjects with moderate-to-severe OSA plus OHS underwent a 1-night trial of CPAP. Both groups were matched for spirometry, BMI, and AHI, but oxygen desaturation was worse in the OSA-plus-OHS group. CPAP significantly improved rapid eye movement (REM) duration (p < 0.005), AHI (p < 0.005), arousal indexes (p < 0.005), and percentage of total sleep time (TST) with oxygen saturation (SpO2) < 90% (p < 0.005) in both groups. In subjects with OSA plus OHS, 43% continued to spend > 20% of TST with SpO2 < 90%, compared to 9% of the OSA group, despite the adequate relief of upper airway obstruction. CONCLUSIONS: Extremely severe obese subjects (BMI >or= 50 kg/m2) with moderate-to-severe OSA plus OHS exhibit severe oxygen desaturation but similar severities of AHI, arousal indexes, and sleep architecture abnormalities when compared to matched subjects without OHS. CPAP significantly improves AHI, REM duration, arousal indexes, and nocturnal oxygen desaturation. Some subjects with OHS continued to have nocturnal desaturation despite the control of upper airway obstruction; other mechanisms may contribute. Further long-term studies assessing the comparative role of CPAP and bilevel ventilatory support in such subjects with OHS is warranted.     

Determinants of continuous positive airway pressure compliance in a group of Chinese patients with obstructive sleep apnea.

OBJECTIVE: To assess continuous positive airway pressure (CPAP) compliance and factors associated with CPAP compliance among Chinese patients with obstructive sleep apnea (OSA). DESIGN: A prospective study of 112 consecutive patients with newly diagnosed OSA commencing CPAP treatment. SETTING: A university teaching hospital. Measurements and results: The following factors were evaluated for any correlation with objective CPAP compliance (effective mask pressure [hours per day]) at 1 month and 3 months: age, baseline apnea-hypopnea index (AHI), common OSA symptoms, minimum arterial oxygen saturation (SaO(2)), mean SaO(2), arousal index (AI), Epworth sleepiness scale (ESS), education level, CPAP levels, satisfaction with CPAP, side effects, and machine cost. There were 101 male and 11 female patients, with a mean (+/- SD) age of 45.6 +/- 1.2 years; body mass index, 29.3 +/- 5.2 kg/m(2); AI, 60 +/- 18/h; AHI, 48 +/- 24/h; minimum SaO(2) of 70 +/- 17%; and mean SaO(2) of 86 +/- 7%. ESS fell from 12.9 +/- 4.0 (baseline) to 5.2 +/- 4.7 at 3 months (p < 0.001). Objective CPAP compliance was 5.4 +/- 1.6 h/d and 5.3 +/- 1.6 h/d, while 75% and 72% of our patients were using CPAP objectively for > or = 4 h/d and at least 70% of the nights per week at 1 month and 3 months, respectively. Following univariate analysis of variance, a high baseline AHI (p = 0.006 and p = 0.004) was associated with higher objective CPAP compliance at 1 month and 3 months, respectively. CONCLUSION: CPAP usage and compliance were high in this patient population. A high baseline AHI was the only significant independent predictor of better CPAP compliance.     

Positive effect of CPAP treatment on the control of difficult-to-treat hypertension.

The aim of the present study was to analyse the role of continuous positive airway pressure (CPAP) treatment in patients with difficult-to-control hypertension (DC-HT) and sleep apnoea. An Autoset (ResMed, Sydney, Australia) study was performed in 60 patients diagnosed with DC-HT based on two 24-h ambulatory blood pressure monitorisation (ABPM) studies. CPAP was offered to patients with an apnoea/hypopnoea index (AHI) > or =15 events.h(-1). After 3 months of treatment, repeat ABPM was performed to evaluate the effect of CPAP upon the blood pressure values. A total of 39 (65%) patients received CPAP treatment, but only 33 completed the study. The mean+/-sd systolic and diastolic blood pressures (SBP and DBP, respectively) were 154.8+/-14 and 90+/-8.8 mmHg. Patients had a mean+/-sd AHI of 37.7+/-18.2 events.h(-1). Only three patients presented a dipper nocturnal pressure pattern. CPAP treatment significantly reduced SBP (-5.2 mmHg), and particularly the nocturnal values (-6.1 mmHg), but not DBP. Considering only those patients who tolerated CPAP, the decrease in SBP was greater (-7.3 mmHg). Furthermore, CPAP treatment significantly increased the percentage of patients who recovered the dipper pattern (three (9.1%) out of 33 versus 12 (36.4%) out of 33). Continuous positive airway pressure treatment significantly reduces systolic blood pressure, particularly at night, and normalises the nocturnal pressure pattern in patients with difficult-to-control hypertension and sleep apnoea.     

Changes in respiratory disorder parameters during the night in patients with obstructive sleep apnoea

Background and objective: Patients with OSA frequently experience cardiovascular events, especially late at night. This phenomenon raises the possibility that respiratory disorders are progressively aggravated during the course of nocturnal sleep. To test this hypothesis, we investigated the changes in respiratory disorder parameters occurring during the night in patients with OSA, in the supine position and in all sleep positions. Methods: Thirty consecutive patients with OSA were enrolled in the study and categorized into those with moderate OSA (n = 12; AHI <40 events/h) and those with severe OSA (n = 18; AHI ≥40 events/h). To identify the time during the sleep period at which changes in respiratory disorder parameters were most pronounced, AHI, mean duration of apnoea and average SaO₂ were assessed during the early, middle and late segments of sleep, in the supine position and in all sleep positions. Results: AHI decreased significantly with time during the course of the total sleep period, and especially during non‐rapid eye movement (NREM) sleep. In the group with severe OSA, prolongation of the mean duration of apnoea and the decrease in average SaO₂ were also significant in the late segment of sleep in the supine position, especially during NREM sleep. Conclusions: In patients with severe OSA, there was progressive prolongation of the mean duration of apnoea late at night and this was associated with aggravation of hypoxia in the supine position during NREM sleep. This phenomenon may contribute to the remarkable rise in blood pressure early in the morning, possibly increasing the vulnerability of these patients to cardiovascular events.     

Ethnicity and socioeconomic status predict initial continuous positive airway pressure compliance in New Zealand adults with obstructive sleep apnoea

Background: Understanding factors that contribute to low continuous positive airway pressure (CPAP) compliance will lead to improvements in the long‐term outcome of patients with obstructive sleep apnoea (OSA) syndrome. Both cultural and socioeconomic factors are likely to be important but have not been systematically studied. Aim: To examine the effect of ethnicity and socioeconomic status on initial CPAP usage for people with OSA in New Zealand. Methods: We retrospectively collected demographic, clinical and CPAP treatment‐related data on patients undergoing a 1‐month CPAP trial for a 10‐month period. We compared objectively measured CPAP usage (by anova ) with self‐identified ethnicity; levels of socioeconomic deprivation (NZDep06 index), Epworth Sleepiness Scale (ESS) and Apnoea‐Hypopnoea Index (AHI). Results: A total of 214 patients with a mean age of 52.7 (±11.8) years, mean AHI 57.3 (±35.8) events per hour and mean ESS 13 (±5.58)/24 made up the cohort. CPAP usage which averaged 5.13 ± 2.34 h per night was significantly lower in patients of non‐European ethnicity (P = 0.019 univariate) and remained significant after socioeconomic status was added to the model (P = 0.048). Patients living in the most socioeconomically deprived areas showed significantly lower compliance with CPAP on univariate analysis (P = 0.024, NZDep06 scores 1&2, average 5.3 per night compared to score NZDep06 scores 9&10, average 4.3 h per night), but this effect was no longer significant once ethnicity was added to the model (P = 0.28). Conclusion: CPAP usage in New Zealand is affected by both ethnicity and level of socioeconomic deprivation. We recommend further research to unravel specific cultural and socioeconomic reasons for the variance reported.     

Home diagnosis of obstructive sleep apnoea in coronary patients: validity of a simplified device automated analysis

Introduction

Our aim was to evaluate a type 3 portable simplified device as a screening tool for obstructive sleep apnoea (OSA) in coronary patients.

Materials and methods

In 50 patients selected independently from sleep complaints, we compared the number of respiratory events per hour of valid recording time counted automatically by the device and the number counted manually per hour of sleep on polysomnography performed at home during the same night.

Results

Five patients were excluded because of technical failures. Estimated OSA prevalences (95% confidence interval) for apnoea/hypopnoea index (AHI) cut-offs ≥5, ≥15, and ≥30 by polysomnography were 0.93 (0.81–0.98), 0.69 (0.53–0.81), and 0.27 (0.15–0.42), respectively. The device would have correctly diagnosed 75% of patients with severe OSA (AHI ≥30 by polysomnography) and would have classified the remaining 25% as having moderate OSA.

Discussion

This ambulatory device may prove valuable in reducing the costs of diagnosing and managing OSA in coronary patients.     

慢性阻塞性肺疾病与致纤维化型间质性肺疾病患者阻塞性睡眠呼吸暂停对比研究

目的探讨阻塞性睡眠呼吸暂停(OSA)与慢性呼吸系统疾病(CRDs)交互作用可能的病理生理机制,对比评价致纤维化型间质性肺疾病(ILD)和慢性阻塞性肺疾病(COPD)患者中OSA的发生情况和严重程度。方法选择2015年9月至2018年12月于中日友好医院呼吸与危重症医学科诊断的73例COPD患者和77例致纤维化型ILD患者,进行多导睡眠监测、肺功能检查和其他临床评估。OSA定义为睡眠呼吸暂停低通气指数(AHI)≥5次/h。结果不依赖于年龄、性别、体质指数(BMI)、白日嗜睡程度及并发症情况,致纤维化型ILD患者较COPD患者发生中、重度OSA更为常见(61%vs. 44%, P=0.02),程度更为严重[AHI(22.4±16.5)次/h vs.(16.8±13.2)次/h, P=0.02]。OSA的严重程度(AHI)与COPD和ILD患者的用力肺活量、肺总量及弥散功能无关。结论 OSA常见于慢性呼吸系统疾病患者,与COPD相比,致纤维化型ILD患者的OSA更为常见,程度更为严重;静态肺功能指标与慢性呼吸系统疾病患者OSA的严重程度无关。提示有必要开展ILD疾病特异性的OSA的临床研究及治疗方式探讨。