Effect of a 2 week CPAP treatment on mood states in patients with obstructive sleep apnea: a double-blind trial

Obstructive sleep apnea (OSA) is a common disease with significant medical and psychiatric comorbidities. The literature documenting the effects of continuous positive airway pressure (CPAP) treatment on mood in OSA patients is mixed. We previously observed that 1 week of CPAP treatment did not result in improvements in mood beyond those observed in a group treated with placebo–CPAP. This study examined the effect of a 2 week CPAP treatment on mood in a placebo-controlled design in OSA patients. Fifty patients with untreated sleep apnea were evaluated by polysomnography and completed the Profile of Mood States (POMS) pre-/post-treatment. The patients were randomized for 2 weeks to either therapeutic CPAP or placebo–CPAP (at insufficient pressure). Both the therapeutic CPAP and the placebo–CPAP groups showed significant improvements in POMS total score, tension, fatigue, and confusion. No significant time × treatment effect was observed for either group. We could not show a specific beneficial impact of CPAP treatment on mood in OSA patients.     

The significance and outcome of continuous positive airway pressure-related central sleep apnea during split-night sleep studies

OBJECTIVE: To determine whether central sleep apnea (CSA) occurring during continuous positive airway pressure (CPAP) titration in patients with obstructive sleep apnea (OSA) reflects subclinical congestive heart failure (CHF), and whether these events will improve with CPAP therapy. DESIGN: Cross-sectional analysis of patients with suspected sleep-related breathing disorders referred for split-night polysomnography PATIENTS AND METHODS: Forty-two OSA patients with and without CPAP-related CSA were analyzed. All CSA patients (n = 21) and control subjects (n = 21) underwent echocardiography, pulmonary function testing, and arterial blood gas (ABG) analysis. Repeat polysomnography with CPAP was performed 2 to 3 months after adequate CPAP therapy in CSA group patients. RESULTS: Demographic, Epworth sleepiness scale, pulmonary function test, ABG, and baseline diagnostic polysomnography findings were similar in both groups. There was no difference in the prevalence of subclinical left ventricular systolic dysfunction in the CSA group vs the control group. CSA patients had decreased sleep efficiency (SE), increased sleep stage 1 percentage, sleep stages shift, wake time after sleep onset (WASO), and total arousals compared to control subjects. Twelve of 14 patients (92%) in the CSA group demonstrated complete or near-complete resolution of CSA events on follow-up polysomnography and showed improvement in SE, WASO, and total arousals compared to their baseline study. CONCLUSIONS: CSA events occurring during CPAP titration are transient and self-limited. They may be precipitated by the sleep fragmentation associated with initial CPAP titration and are not associated with an increased prevalence of occult CHF compared to OSA patients without CPAP-related CSA.     

快速眼动睡眠期的阻塞型呼吸暂停与高血压

快速眼动(REM)睡眠期阻塞型睡眠呼吸暂停(OSA)是指发生在REM期的阻塞型睡眠呼吸暂停综合征,由于REM期交感神经活性异常增高,因此发生在此期的OSA可以使交感神经活性更高,心血管功能更不稳定。目前认为REM-OSA很可能是OSA相关高血压发生的主要原因,并且也可能是目前OSA相关高血压用持续正压通气(CPAP)治疗效果不明显的重要原因。临床工作中应重视对REM-OSA的诊断和治疗,这对OSA相关高血压的防治具有重要意义。     

Heart Rate Variability in Obstructive Sleep Apnea: A Prospective Study and Frequency Domain Analysis

Background: Cyclic variation of the heart rate is observed during apneic spells in obstructive sleep apnea (OSA). We hypothesized that autonomic changes would affect frequency‐domain measures of heart rate variability (HRV). Methods: We studied 20 patients (15 men, 5 women, mean age 47.2 ± 12.2 years) with suspected OSA undergoing overnight polysomnography, and five patients (4 men, 1 woman, mean age 49.2 ± 8.6 years) with recently diagnosed sleep apnea undergoing polysomnography while wearing continuous positive airway pressure (CPAP). Holter monitors were applied during sleep studies and data were analyzed in 5‐minute blocks over the course of the night. Using spectral analysis, low frequency (LF) and high frequency (HF) powers were calculated for each interval. Overall mean and standard deviation (SD) for LF power, HF power, and the LF:HF ratio were recorded for each patient. Comparisons were made between patients with severe OSA (apnea hypopnea index (AHI) > 30, n = 8 ), moderate OSA (AHI 1–30, n = 5 ), without OSA (AHI < 10, n = 7 ), and patients wearing CPAP (n = 5 ). Results: Assessment of overnight LF or HF power revealed no significant difference between the four groups. The LF:HF ratio, which represents sympathovagal balance, was higher among those with moderate disease compared to normals and those with severe OSA (both P = 0.037 ). The standard deviation of the LF:HF ratio was higher among those with moderate disease compared to normals (P = 0.0064) and those with severe OSA (P = 0.0006) . OSA patients receiving CPAP behaved like patients with moderate OSA, with increased SD of the LF:HF ratio. Conclusions: The observed changes in the LF:HF ratio and its SD suggest an increased sympathetic tone and discordance in sympathovagal activity in moderate OSA, which is blunted in severe OSA. CPAP may restore autonomic defects, characteristic of severe OSA, to moderate levels.     

A continuous positive airway pressure trial as a novel approach to the diagnosis of the obstructive sleep apnea syndrome

OBJECTIVES: Treatment of obstructive sleep apnea syndrome (OSA) is often delayed because polysomnography, the recommended standard diagnostic test, is not readily available. We evaluated whether the diagnosis of sleep apnea could be inferred from the response to a treatment trial with nasal continuous positive airway pressure (CPAP). DESIGN: Study on diagnostic accuracy. SETTING: Sleep-disorders clinic of a university hospital. PATIENTS: Seventy-six sleepy snorers consecutively referred for sleep apnea evaluation. INTERVENTIONS: CPAP treatment trial over 2 weeks as an initial diagnostic test in comparison with polysomnography, and treatment success over > or = 4 months. MEASUREMENTS AND RESULTS: The main outcome was diagnostic accuracy of the CPAP trial. The trial result was positive if the patient had used CPAP for > 2 h per night and wished to continue therapy. This suggested sleep apnea. The trial was evaluated in terms of predicting an obstructive apnea/hypopnea index (AHI) > 10/h during polysomnography performed for validation, and in terms of identifying sleep apnea patients treated successfully over > or = 4 months. Forty-four of 76 patients (58%) had sleep apnea as confirmed by an AHI > 10/h. The CPAP trial predicted sleep apnea with a sensitivity of 80%, a specificity of 97%, and positive and negative predictive values of 97% and 78%, respectively. In 35 of 76 sleep apnea patients (46%) with positive CPAP trial results, polysomnography could have been avoided. These patients were prescribed long-term CPAP therapy. After 4 months, 33 of 35 patients (94%) still used CPAP, and their symptoms remained improved. These patients were identified by the CPAP trial with positive and negative predictive values of 92% and 100%, respectively. CONCLUSIONS: In a selected population, a CPAP trial may help to diagnose OSA, to identify patients who benefit from CPAP, and to reduce the need for polysomnography.     

Position paper by Canadian dental sleep medicine professionals regarding the role of different health care professionals in managing obstructive sleep apnea and snoring with oral appliances

The present Canadian position paper contains recommendations for the management by dentists of sleep-disordered breathing in adults with the use of oral appliances (OAs) as a treatment option for snoring and obstructive sleep apnea (OSA). The recommendations are based on literature reviews and expert panel consensus. OAs offer an effective, first-line treatment option for patients with mild to moderate OSA who prefer an OA to continuous positive airway pressure (CPAP) therapy, or for severe OSA patients who cannot tolerate CPAP, are inappropriate candidates for CPAP or who have failed CPAP treatment attempts. The purpose of the present position paper is to guide interdisciplinary teamwork (sleep physicians and sleep dentists) and to clarify the role of each professional in the management of OA therapy. The diagnosis of OSA should always be made by a physician, and OAs should be fitted by a qualified dentist who is trained and experienced in dental sleep medicine. Follow-up assessment by the referring physician and polysomnography or sleep studies are required to verify treatment efficacy. The present article emphasizes the need for a team approach to OA therapy and provides treatment guidelines for dentists trained in dental sleep medicine. Many of the dentists and sleep physicians who contributed to the preparation of the present article are members of the Canadian Sleep Society and the authors reached a consensus based on the current literature.     

Correction of AV-nodal block in a 27-year-old man with severe obstructive sleep apnea--a case report

A 27-year-old morbidly obese man diagnosed with severe obstructive sleep apnea (OSA) and experiencing significant ventricular asystoles at times exceeding 8 seconds, during polysomnography. The bradyarrhythmias were successfully corrected with the application of a nasal continuous positive airway pressure (CPAP) mask. Follow-up 24-hour ambulatory Holter monitoring without the aid of a nasal CPAP mask and repeat polysomnography with a CPAP mask after several weeks of continuous CPAP therapy during sleep revealed no evidence of ventricular asystole, despite no change in the patient's body mass index. We discuss several mechanisms explaining the findings in this particular patient.     

Obstructive sleep apnea therapy for cardiovascular risk reduction—Time for a rethink?

Obstructive sleep apnea (OSA) is a highly prevalent and underdiagnosed medical condition, which is associated with various cardiovascular and metabolic diseases. The current mainstay of therapy is continuous positive airway pressure (CPAP); however, CPAP is known to be poorly accepted and tolerated by patients. In randomized controlled trials evaluating CPAP in cardiovascular outcomes, the average usage was less than 3.5 hours, which is below the 4 hours per night recommended to achieve a clinical benefit. This low adherence may have resulted in poor effectiveness and failure to show cardiovascular risk reduction. The mandibular advancement device (MAD) is an intraoral device designed to advance the mandible during sleep. It functions primarily through alteration of the jaw and/or tongue position, which results in improved upper airway patency and reduced upper airway collapsibility. The MAD is an approved alternative therapy that has been consistently shown to be the preferred option by patients who are affected by OSA. Although the MAD is less efficacious than CPAP in abolishing apnea and hypopnea events in some patients, its greater usage results in comparable improvements in quality‐of‐life and cardiovascular measures, including blood pressure reduction. This review summarizes the impact of OSA on cardiovascular health, the limitations of CPAP, and the potential of OSA treatment using MADs in cardiovascular risk reduction.     

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.     

Mechanisms of nocturnal gastroesophageal reflux events in obstructive sleep apnea

Purpose  

Obstructive sleep apnea (OSA) is associated with increased nocturnal gastroesophageal reflux (nocturnal GER) events and symptoms. Treatment of OSA with continuous positive airway pressure (CPAP) reduces nocturnal GER in patients with OSA. This study sought to determine the: (1) relationship of nocturnal GER events with apnea/hypopnea and arousal, (2) effect of upper airway obstruction on the barrier function of the lower esophageal sphincter (LES), (3) mechanism of LES failure for each nocturnal GER event and (4) effect of CPAP on LES function during sleep.     

Patient experience with upper airway stimulation in the treatment of obstructive sleep apnea

Sleep and Breathing - Selective upper airway stimulation (sUAS) is a new treatment modality for patients with obstructive sleep apnea (OSA) and continuous positive airway pressure (CPAP) failure....     

Impact of continuous positive airway pressure on vascular endothelial growth factor in patients with obstructive sleep apnea: a meta-analysis

Purpose

Cumulative evidence supports the clear relationship of obstructive sleep apnea (OSA) with cardiovascular disease (CVD). And, adherence to continuous positive airway pressure (CPAP) treatment alleviates the risk of CVD in subjects with OSA. Vascular endothelial growth factor (VEGF), a potent angiogenic cytokine regulated by hypoxia-inducible factor, stimulates the progression of CVD. Thus, whether treatment with CPAP can actually decrease VEGF in patients with OSA remains inconclusive. The purpose of the present study was to quantitatively evaluate the impact of CPAP therapy on VEGF levels in OSA patients.

Methods

We systematically searched Web of Science, Cochrane Library, PubMed, and Embase databases that examined the impact of CPAP on VEGF levels in OSA patients prior to May 1, 2017. Related searching terms were “sleep apnea, obstructive,” “sleep disordered breathing,” “continuous positive airway pressure,” “positive airway pressure,” and “vascular endothelial growth factor.” We used standardized mean difference (SMD) to analyze the summary estimates for CPAP therapy.

Results

Six studies involving 392 patients were eligible for the meta-analysis. Meta-analysis of the pooled effect showed that levels of VEGF were significantly decreased in patients with OSA before and after CPAP treatment (SMD?=???0.440, 95% confidence interval (CI)?=???0.684 to ??0.196, z?=?3.53, p?=?0.000). Further, results demonstrated that differences in age, body mass index, apnea–hypopnea index, CPAP therapy duration, sample size, and racial differences also affected CPAP efficacy.

Conclusions

Improved endothelial function measured by VEGF may be associated with CPAP therapy in OSA patients. The use of VEGF levels may be clinically important in evaluating CVD for OSA patients. Further large-scale, well-designed long-term interventional investigations are needed to clarify this issue.

     

Cycle length identifies obstructive sleep apnea and central sleep apnea in heart failure with reduced ejection fraction

Aim

To clarify whether unmasking of central sleep apnea during continuous positive airway pressure (CPAP) initiation can be identified from initial diagnostic polysomnography (PSG) in patients with heart failure with reduced ejection fraction (HFREF) and obstructive sleep apnea (OSA)

Materials and methods

Forty-three consecutive patients with obstructive sleep apnea and central sleep apnea (OSA/CSA) in HFREF were matched with 43 HFREF patients with OSA and successful CPAP initiation. Obstructive apneas during diagnostic PSG were then analyzed for cycle length (CL), ventilation length (VL), apnea length (AL), time to peak ventilation (TTPV), and circulatory delay (CD). We calculated duty ratio (DR) as the ratio of VL/CL and mathematic loop gain (LG).

Results

While AL was similar, CL, VL, TTPV, CD, and DR was significantly longer in patients with OSA/CSA compared to those with OSA, and LG was significantly higher. Receiver operator curves identified optimal cutoff values of 50.2 s for CL (area under the curve (AUC) 0.85, 29.2 s for VL (AUC 0.92), 11.5 s for TTPV (AUC 0.82), 26.4 s for CD (AUC 0.79), and 3.96 (AUC 0.78)) respectively for LG to identify OSA/CSA.

Conclusion

OSA/CSA in HFREF can be identified by longer CL, VL, TTPV, and CD from obstructive events in initial diagnostic PSG. The underlying mechanisms seem to be the presence of an increased LG.

     

Determinants of continuous positive airway pressure adherence in a sleep clinic cohort of South Florida Hispanic veterans

Purpose

There are little existing data on continuous positive airway pressure (CPAP) adherence in US Hispanic veterans with obstructive sleep apnea (OSA). Our aim was to describe determinants of 1-month adherence in a sleep clinic cohort of South Florida Hispanic veterans.

Methods

Hispanic veterans referred to the Miami VA sleep clinic were recruited and completed questionnaires about sleep apnea risk, sleep quality, insomnia symptoms, sleepiness, depression/anxiety, acculturation, personality traits, and cognitions about OSA and CPAP. Individuals at risk for OSA were scheduled for baseline polysomnography (PSG), followed by in-lab CPAP titration or a trial of auto-CPAP. Participants with OSA accepting CPAP therapy were asked to return after 7 and 30 days of treatment for adherence verification and to repeat questionnaires.

Results

One hundred twenty-four participants (94 % men) were enrolled with 114 completing overnight PSG. Eighty-six out of 95 participants (91 %) with sleep apnea syndrome or moderate to severe OSA accepted CPAP treatment. Fifty-nine participants completed both follow-up visits with a mean CPAP use at 30 days of 3.6?±?2.0 h. The only independent predictor of 7-day mean daily CPAP use was the baseline Insomnia Severity Index while the best predictor of 30-day mean daily CPAP use was the 7-day mean daily use.

Conclusions

Our study suggests that South Florida Hispanic veterans with OSA evaluated in a sleep clinic show poor CPAP adherence. Insomnia and poor early use predicted poor adherence overall. Larger prospective studies with other race–ethnic groups are needed to determine the role of ethnicity and race in CPAP adherence among US veterans with OSA.     

Obstructive sleep apnea in infants and its management with nasal continuous positive airway pressure.

STUDY OBJECTIVES: Nasal continuous positive airway pressure (nCPAP) is the most common treatment for obstructive sleep apnea (OSA) in adults, and it has been effective in the treatment of OSA in children. We wanted to determine the effectiveness of long-term nCPAP therapy for OSA in infants. PATIENTS: Twenty-four infants who had OSA were treated with nCPAP via nose mask. These infants had clinical histories that included a family history of sudden infant death syndrome, an apparent life-threatening event, or facial and upper airway anatomic abnormalities. INTERVENTIONS: Overnight polysomnographic studies were performed to assess the severity of OSA in each infant and to determine the appropriate level of continuous positive airway pressure (CPAP). Studies were repeated to determine the progress of OSA and the continuing need for CPAP in each infant. RESULTS: nCPAP pressures between 4 and 6 cm H2O prevented obstruction and reversed sleep disturbances that were associated with OSA. Eighteen of the infants continued treatment at home from 1 month to > 4 years. CPAP therapy was discontinued in 13 infants after their OSA resolved. Five infants who have upper airway anatomic abnormalities remain on CPAP, and the pressure level required to prevent obstructive events during sleep has needed to be increased to as high as 10 cm H2O. CONCLUSIONS: nCPAP is an effective therapy for the management of OSA in infants, and it can be used effectively in the home environment. Regular follow-up is necessary, because the requirements for CPAP and pressure levels change with the infant's growth and development.     

Flow-volume curves reflect pharyngeal airway abnormalities in sleep apnea syndrome

Twenty-nine patients with disorders of excessive somnolence were evaluated with standard nocturnal polysomnography, fiberoptic laryngoscopy, and flow-volume curves. Twenty-two had evidence of obstructive sleep apnea (OSA) by polysomnography and most had abnormal flow-volume curves, supporting earlier observations. Three of 7 patients without obstructive sleep apnea also had abnormal curves. Fiberoptic nasopharyngoscopy was performed in the OSA group while awake to evaluate the upper airway. Sixteen patients of the OSA group demonstrated pharyngeal obstruction; 14 of those with visualized airway obstruction had flow-volume abnormalities. In the 6 patients of the OSA group with no significant visual obstruction, 5 had normal curves. The flow-volume curve appears to correlate with direct visual assessment of upper airway patency during wakefulness in those patients demonstrating obstruction during sleep.     

Rapid eye movement and slow-wave sleep rebound after one night of continuous positive airway pressure for obstructive sleep apnoea

Background and objective: Rebound of slow‐wave sleep (SWS) and rapid eye movement (REM) sleep is observed in patients who are on continuous positive airway pressure (CPAP) therapy for obstructive sleep apnoea (OSA); but, neither have been objectively defined. The pressure titration study often represents the first recovery sleep period for patients with OSA. Our aim was to objectively define and identify predictors of SWS and REM sleep rebound following CPAP titration. Methods: Paired diagnostic polysomnography and pressure titration studies from 335 patients were reviewed. Results: The mean apnoea‐hypopnoea index was 40.7 ± 26.1, and minimum oxygen saturation was 76 ± 14.4%. Comparing eight incremental thresholds, a rebound of 20% in REM sleep and a 40% increase in SWS allowed the best separation of prediction models. A 20% rebound in REM sleep was predicted by REM sleep %, non‐REM arousal index (ArI) and total sleep time during diagnostic polysomnography, and male gender (R² = 35.3%). A 40% rebound in SWS was predicted by SWS %, total ArI and REM sleep % during diagnostic polysomnography, and body mass index (R² = 45.4%). Conclusions: A 40% rebound in SWS, but only a 20% rebound in REM sleep on the pressure titration study, is predicted by abnormal sleep architecture and sleep fragmentation prior to the commencement of treatment.     

Influence of obstructive sleep apnea and treatment with continuous positive airway pressure on fractional flow reserve measurements for coronary lesion assessment

Obstructive sleep apnea (OSA) and sleep‐disordered breathing have been implicated in the progression of cardiovascular disease and with increased risk of coronary artery disease, congestive heart failure, and stroke. Fractional flow reserve (FFR) is used to evaluate the physiological significance of coronary artery stenosis, and this technique is largely thought to be independent of systemic hemodynamic changes. Herein, we describe a case of OSA and sleep‐disordered breathing cyclically altering FFR measurements from normal to abnormal in a patient with coronary artery disease. More specifically, we show that the abnormal FFR across a coronary lesion in a patient with sleep disordered apnea improves (to a normal threshold) with the initiation of continuous positive airway pressure (CPAP). This finding may have implications for the mechanisms of cardiac dysfunction in patients with OSA. © 2009 Wiley‐Liss, Inc.     

Blood pressure variability in obstructive sleep apnea: role of sympathetic nervous activity and effect of continuous positive airway pressure

BACKGROUND: Many studies support a link between obstructive sleep apnea (OSA), increased blood pressure (BP) and/or BP variability, and sympathetic nervous system (SNS) activity. We assessed the relationship between SNS activity and 24-h BP variability in patients with OSA, and the effect of continuous positive airway pressure (CPAP) on BP variability. DESIGN: Forty-one patients with a respiratory disturbance index (RDI) > 15 were randomized into CPAP or CPAP placebo groups for a 1-week trial. METHODS: Ambulatory BP, 24-h urine norepinephrine (NE) and polysomnography were measured prior to treatment and after 1 and 7 days of treatment. RESULTS: Neither RDI nor 24-h urine NE levels were related to 24-h mean BP levels. While RDI was associated only with night-time BP variability, daytime urine NE levels were associated with both night-time and daytime BP variability. After treatment, the BP variability decreased significantly but equally in both active and placebo CPAP groups. CONCLUSIONS: Obstructive sleep apnea is more related to BP variability than BP. Sympathetic nervous activity, as inferred from daytime urine NE, is related to changes in BP variability in OSA patients. BP variability is not specifically affected by CPAP.