Influence of obstructive sleep apnea on serum butyrylcholinesterase activity and ischemia-modified albumin levels

OBJECTIVE:

To investigate the effect of obstructive sleep apnea and continuous positive airway pressure treatment on serum butyrylcholinesterase activity and ischemia-modified albumin levels.

METHODS:

Thirty-two patients with obstructive sleep apnea and 30 age- and sex-matched controls were enrolled and underwent a diagnostic polysomnogram. The serum butyrylcholinesterase activity, ischemia-modified albumin levels, metabolic parameters, and polysomnography scores were detected and evaluated. Nine patients were studied before and after treatment with continuous positive airway pressure.

RESULTS:

The serum ischemia-modified albumin levels were significantly higher and the butyrylcholinesterase activity was significantly lower in patients with obstructive sleep apnea than in the controls (p<0.001). The continuous positive airway pressure treatment decreased the modified albumin levels and elevated the buthrylcholinesterase activity (p = 0.019 and p = 0.023, respectively). The modified albumin levels were positively correlated with the apnea-hypopnea index (r = 0.462, p = 0.008) at baseline. Elevated ischemia-modified albumin levels can be more accurate than butyrylcholinesterase activity at reflecting the presence of obstructive sleep apnea. Receiver operating characteristic curves revealed a significant difference between the areas under the curve 0.916 for ischemia-modified albumin and 0.777 for butyrylcholinesterase (z = 2.154, p = 0.031).

CONCLUSION:

The elevated ischemia-modified albumin level was significantly associated with obstructive sleep apnea and was more sensitive than butyrylcholinesterase activity in reflecting obstructive sleep apnea. The continuous positive airway pressure treatment helped to ameliorate the imbalance.     

The use of nasal dilator strips as a placebo for trials evaluating continuous positive airway pressure

OBJECTIVES:

The aim of the current study was to compare the objective and subjective effects of continuous positive airway pressure to the use of nasal dilator strips in patients with acromegaly and moderate to severe obstructive sleep apnea.

METHODS:

We studied 12 patients with acromegaly and moderate to severe obstructive sleep apnea (male/females = 8/4, age = 52±8 ys, body mass index = 33.5±4.6 Kg/m², apnea–hypopnea index = 38±14 events/h) who had been included in a randomized, crossover study to receive three months of treatment with continuous positive airway pressure and nasal dilator strips. All patients were evaluated at study entry and at the end of each treatment by polysomnography, and Epworth Sleepiness Scale, Pittsburgh Sleep Quality Index and treatment satisfaction questionnaires. ClinicalTrials.gov: NCT01265121

RESULTS:

The apnea–hypopnea index values decreased significantly with continuous positive airway pressure treatment but did not change with the use of nasal dilator strips. All of the subjective symptoms improved with both treatments, but these improvements were significantly greater with continuous positive airway pressure than with the nasal dilator strips.

CONCLUSION:

The use of nasal dilator strips had a much smaller effect on the severity of obstructive sleep apnea in patients with acromegaly and moderate to severe obstructive sleep apnea in comparison to the use of continuous positive airway pressure. Moreover, the improvement in several subjective parameters without any significant objective improvement in obstructive sleep apnea resulting from the use of nasal dilator strips is compatible with a placebo effect.     

Lack of reliable clinical predictors to identify obstructive sleep apnea in patients with hypertrophic cardiomyopathy

OBJECTIVE:

Obstructive sleep apnea is common among patients with hypertrophic cardiomyopathy and may contribute to poor cardiovascular outcomes. However, obstructive sleep apnea is largely unrecognized in this population. We sought to identify the clinical predictors of obstructive sleep apnea among patients with hypertrophic cardiomyopathy.

METHODS:

Consecutive patients with hypertrophic cardiomyopathy were recruited from a tertiary University Hospital and were evaluated using validated sleep questionnaires (Berlin and Epworth) and overnight portable monitoring. Ninety patients (males, 51%; age, 46±15 years; body mass index, 26.6±4.9 kg/m²) were included, and obstructive sleep apnea (respiratory disturbance index ≥15 events/h) was present in 37 patients (41%).

RESULTS:

Compared with the patients without obstructive sleep apnea, patients with obstructive sleep apnea were older and had higher body mass index, larger waist circumference, larger neck circumference, and higher prevalence of atrial fibrillation. Excessive daytime sleepiness (Epworth scale) was low and similar in the patients with and without obstructive sleep apnea, respectively. The only predictors of obstructive sleep apnea (using a logistic regression analysis) were age ≥45 years (odds ratio [OR], 4.46; 95% confidence interval [CI 95%], 1.47–13.54; p = 0.008) and the presence of atrial fibrillation [OR, 5.37; CI 95%, 1.43–20.12; p = 0.013].

CONCLUSION:

Consistent clinical predictors of obstructive sleep apnea are lacking for patients with hypertrophic cardiomyopathy, which suggests that objective sleep evaluations should be considered in this population, particularly among elderly patients with atrial fibrillation.     

Daytime Sleepiness and Driving Performance in Patients with Obstructive Sleep Apnea: Comparison of the MSLT,the MWT,and a Simulated Driving Task

Study Objectives:

To test the reliability of a driving-simulation test for the objective measurement of daytime alertness compared with the Multiple Sleep Latency Test (MSLT) and with the Maintenance of Wakefulness Test (MWT), and to test the ability to drive safely, in comparison with on-road history, in the clinical setting of untreated severe obstructive sleep apnea.

Design:

N/A.

Setting:

Sleep laboratory.

Patients or Participants:

Twenty-four patients with severe obstructive sleep apnea and reported daytime sleepiness varying in severity (as measured by the Epworth Sleepiness Scale).

Interventions:

N/A.

Measurements and Results:

Patients underwent MSLT and MWT coupled with 4 sessions of driving-simulation test on 2 different days randomly distributed 1 week apart. Simulated-driving performance (in terms of lane-position variability and crash occurrence) was correlated with sleep latency on the MSLT and more significantly on the MWT, showing a predictive validity toward the detection of sleepy versus alert patients with obstructive sleep apnea. In addition, patients reporting excessive daytime sleepiness or a history of car crashes showed poorer performances on the driving simulator.

Conclusions:

A simulated driving test is a suitable tool for objective measurement of daytime alertness in patients with obstructive sleep apnea. Further studies are needed to clarify the association between simulated-driving performance and on-road crash risk of patients with sleep disordered breathing.

Citation:

Pizza F; Contardi S; Mondini S; Trentin L; Cirignotta F. Daytime sleepiness and driving performance in patients with obstructive sleep apnea: comparison of the MSLT, the MWT, and a simulated driving task. SLEEP 2009;32(3):382-391.     

Randomized Controlled Trial of Variable-Pressure Versus Fixed-Pressure Continuous Positive Airway Pressure (CPAP) Treatment for Patients with Obstructive Sleep Apnea/Hypopnea Syndrome (OSAHS)

Study Objectives:

To determine whether fixed-pressure or variable-pressure CPAP was preferred by patients and gave better outcomes in patients with the obstructive sleep apnea/hypopnea syndrome (OSAHS).

Design:

Randomized blinded cross-over trial with 6 weeks of fixed and 6 weeks of variable-pressure CPAP

Setting:

Sleep center

Patients:

200 consecutive consenting CPAP naive patients with daytime sleepiness and >15 apneas + hypopneas/h after an attended auto-CPAP titration night.

Interventions:

CPAP therapy using the same device (Autoset Spirit) set for 6 weeks in fixed pressure mode and for 6 weeks in variable pressure mode, the order of therapies being randomized.

Measurements and Results:

All measurements were recorded at the end of each limb by a researcher blind to treatment. These included symptoms, Epworth Score, CPAP usage, objective sleepiness by modified Osler test, vigilance and health related quality of life. A total of 181 of 200 patients completed the study. At the end of the study, patients expressed no significant difference in the primary outcome, patient preference, 72 patients preferring fixed and 69 preferring variable-pressure CPAP. Epworth score was lower on variable (9.5, SEM 0.4) than fixed-pressure CPAP (10.0, SEM 0.3; P = 0.031). Mean CPAP use was higher on variable (4.2, SEM 0.2 h/night) than fixed-pressure CPAP (4.0, SEM 0.2 h/night; P = 0.047). There were no other significant differences between treatments.

Conclusions

This study shows no difference in patient preference and only a marginal benefit of variable over fixed-pressure CPAP in OSAHS in terms of subjective sleepiness and CPAP use. The clinical value of this difference remains to be determined.

Clinical Trial Information:

Variable-pressure versus fixed-pressure continuous positive airway pressure (CPAP) treatment for patients with obstructive sleep apnoea/hypopnoea syndrome (OSAHS); Registration # ISRCTN43085025; http://www.controlled-trials.com/ISRCTN43085025

Citation:

Vennelle M; White S; Riha RL; Mackay T; Engleman HM; Douglas NJ. Randomized controlled trial of variable-pressure versus fixed-pressure continuous positive airway pressure (CPAP) treatment for patients with obstructive sleep apnea/hypopnea syndrome (OSAHS). SLEEP 2010;33(2):267-271.     

Effects of continuous positive airway pressure on neurocognitive and neuropsychiatric function in obstructive sleep apnea

The aim of this study was to determine the neurocognitive and neuropsychiatric effects of continuous positive airway pressure treatment on patients with obstructive sleep apnea. This cross‐sectional, prospective, observational study included 126 patients with sleep apnea. The following tests were performed: the Montreal Cognitive Assessment for the evaluation of cognitive impairment, the Beck Depression Inventory, and the State‐Trait Anxiety Inventory, together with the Epworth Sleepiness Scale for the evaluation of neuropsychiatric symptoms and a person's general level of daytime sleepiness. The first measurement did not show neurocognitive impairment or a higher level of depressive and anxiety symptoms in 126 patients with obstructive sleep apnea in comparison to normative standards. After the 3‐month treatment indicated for 43 patients with obstructive sleep apnea, we did not find any significant improvement in cognitive performance (p = .213). However, patients with sleep apnea with continuous positive airway pressure treatment did show significantly less daytime sleepiness, anxiety and depressive symptoms (all p < .001). In conclusion, short‐term (3 months) treatment of patients with obstructive sleep apnea can substantially alleviate their daytime sleepiness, as well as depressive and anxiety symptoms.     

Quality of life among untreated sleep apnea patients compared with the general population and changes after treatment with positive airway pressure

Obstructive sleep apnea leads to recurrent arousals from sleep, oxygen desaturations, daytime sleepiness and fatigue. This can have an adverse impact on quality of life. The aims of this study were to compare: (i) quality of life between the general population and untreated patients with obstructive sleep apnea; and (ii) changes of quality of life among patients with obstructive sleep apnea after 2 years of positive airway pressure treatment between adherent patients and non‐users. Propensity score methodologies were used in order to minimize selection bias and strengthen causal inferences. The enrolled obstructive sleep apnea subjects (n = 822) were newly diagnosed with moderate to severe obstructive sleep apnea who were starting positive airway pressure treatment, and the general population subjects (n = 742) were randomly selected Icelanders. The Short Form 12 was used to measure quality of life. Untreated patients with obstructive sleep apnea had a worse quality of life when compared with the general population. This effect remained significant after using propensity scores to select samples, balanced with regard to age, body mass index, gender, smoking, diabetes, hypertension and cardiovascular disease. We did not find significant overall differences between full and non‐users of positive airway pressure in improvement of quality of life from baseline to follow‐up. However, there was a trend towards more improvement in physical quality of life for positive airway pressure‐adherent patients, and the most obese subjects improved their physical quality of life more. The results suggest that co‐morbidities of obstructive sleep apnea, such as obesity, insomnia and daytime sleepiness, have a great effect on life qualities and need to be taken into account and addressed with additional interventions.     

An overlooked cause of resistant hypertension: upper airway resistance syndrome - preliminary results

OBJECTIVE:

Upper airway resistance syndrome is a sleep-disordered breathing syndrome that is characterized by repetitive arousals resulting in sympathetic overactivity. We aimed to determine whether upper airway resistance syndrome was associated with poorly controlled hypertension.

METHODS:

A total of 40 patients with resistant hypertension were enrolled in the study. All of the patients underwent polysomnographic examinations and 24-hour ambulatory blood pressure monitoring to exclude white coat syndrome and to monitor treatment efficiency. Among 14 upper airway resistance syndrome patients, 2 patients had surgically correctable upper airway pathologies, while 12 patients were given positive airway pressure therapy.

RESULTS:

All patients underwent polysomnographic examinations; 22 patients (55%) were diagnosed with obstructive sleep apnea and 14 patients (35%) were diagnosed with upper airway resistance syndrome, according to American Sleep Disorders Association criteria. The patients with upper airway resistance syndrome were younger and had a lower body mass index compared with other patients, while there were no difference between the blood pressure levels and the number of antihypertensive drugs. The arousal index was positively correlated with systolic blood pressure level (p = 0.034; r_s = 0.746), while the Epworth score and AHI were independent of disease severity (p = 0.435, r_s = 0.323 and p = 0.819, r_s = -0.097, respectively). Eight patients were treated with positive airway pressure treatment and blood pressure control was achieved in all of them, whereas no pressure reduction was observed in four untreated patients.

CONCLUSIONS:

We conclude that upper airway resistance syndrome is a possible secondary cause of resistant hypertension and that its proper treatment could result in dramatic blood pressure control.     

Sleep Measures and Morning Plasma TNF-α Levels in Children with Sleep-Disordered Breathing

Background:

Sleep disordered breathing in children is associated with severity-dependent increases in excessive daytime sleepiness (EDS). TNF-α is an inflammatory cytokine that has been implicated in EDS. Since, at any given level of apnea-hypopnea index, there is significant variability in EDS, we hypothesized that morning tumor necrosis factor (TNF)-α plasma levels may provide a biologic correlate of EDS.

Methods:

Children being evaluated for sleep disordered breathing underwent a blood draw after nocturnal polysomnography, and TNF-α plasma concentrations were assayed using ELISA. In a subset of 15 children with sleep disordered breathing and in 15 matched control subjects, whole blood cultures in the presence of lipopolysaccharide and Multiple Sleep Latency Test were conducted. Furthermore, 22 children with obstructive sleep apnea had TNF-α levels assayed and underwent nocturnal polysomnography and Multiple Sleep Latency Test before and after adenotonsil-lectomy.

Results:

In 298 children, morning TNF-α levels were globally increased in the presence of obstructive sleep apnea, particularly in more severe cases, and correlated with obstructive apnea-hypopnea index and sleep pressure score, a measure of respiratory-induced sleep fragmentation, but not with nadir SaO₂. A stepwise logistic regression analysis revealed that sleep pressure score and body mass index accounted for 36.2% of the adjusted variance in TNF-α levels (P < 0.0001). Furthermore, multiple sleep latencies were correlated with whole blood culture-derived TNF-α levels (n = 15), and morning TNF-α levels decreased after adenotonsillectomy in 22 children.

Conclusions:

TNF-α levels are increased in pediatric obstructive sleep apnea, are primarily driven by sleep fragmentation and body mass index, and are closely associated with the degree of sleepiness, as measured by Multiple Sleep Latency Test. Furthermore, surgical treatment of obstructive sleep apnea results in significant reductions in TNF-α levels with reciprocal prolongations in sleep latency.

Citation:

Gozal D; Serpero LD; Kheirandish-Gozal L; Capdevila OS; Khalyfa A; Tauman R. Sleep measures and morning plasma TNF-α levels in children with sleep-disordered breathing. SLEEP 2010;33(3):319-325.     

Randomized Controlled Trial Comparing Flexible and Continuous Positive Airway Pressure Delivery: Effects on Compliance,Objective and Subjective Sleepiness and Vigilance

Study Objectives:

Positive airway pressure (PAP) treatment for obstructive sleep apnea (OSA) can be limited by suboptimal compliance. C-Flex technology (Philips Respironics, PA, USA) reduces pressure during expiration, aiming to improve comfort and therefore compliance. This may be of particular relevance to patients requiring high pressures. Many studies thus far have suffered from design limitations and small sample sizes. This study aimed to compare compliance with C-Flex and CPAP, as well as analyzing objective and subjective sleepiness and vigilance.

Design:

Three-month, double-blinded, parallel-arm randomized controlled trial.

Setting:

A university-based sleep laboratory.

Patients:

76 consecutive patients with severe OSA (mean ± SD AHI 60.2 ± 32.9 events/hour, ESS 13.6 ± 4.5/24, BMI 35.6 ± 7.8 kg/m²), without significant cardiac, respiratory, psychiatric, or sleep comorbidities.

Interventions:

Patients were randomized to C-Flex (dip level 2) or CPAP.

Measurements and Results:

Patients underwent titration with C-Flex/CPAP (mean pressure 11.6 cm H₂O). Modified maintenance of wakefulness tests (mod-MWT), psychomotor vigilance tasks (PVT) and questionnaires were administered at baseline and after one and 3 months. Median compliance was 5.51 and 5.89 h/ night in the C-Flex and CPAP groups respectively (P = 0.82). There were no significant differences between groups in terms of PVT reaction time, subjective sleepiness, sleep quality, health-related quality of life, or treatment comfort. There was no significant difference between the groups regarding the change in mod-MWT sleep latency values.

Conclusions:

In patients with severe OSA both CPAP and C-Flex resulted in substantial improvements in sleepiness, vigilance, and quality of life. The use of C-Flex did not result in greater compliance, and neither treatment appeared superior.

Citation:

Bakker J; Campbell A; Neill A. Randomized controlled trial comparing flexible and continuous positive airway pressure delivery: effects on compliance, objective and subjective sleepiness and vigilance. SLEEP 2010;33(4):523-529.     

Practice parameters for the surgical modifications of the upper airway for obstructive sleep apnea in adults

Background:

Practice parameters for the treatment of obstructive sleep apnea syndrome (OSAS) in adults by surgical modification of the upper airway were first published in 1996 by the American Academy of Sleep Medicine (formerly ASDA). The following practice parameters update the previous practice parameters. These recommendations were reviewed and approved by the Board of Directors of the American Academy of Sleep Medicine.

Methods:

A systematic review of the literature was performed, and the GRADE system was used to assess the quality of evidence. The findings from this evaluation are provided in the accompanying review paper, and the subsequent recommendations have been developed from this review. The following procedures have been included: tracheostomy, maxillo-mandibular advancement (MMA), laser assisted uvulopalatoplasty (LAUP), uvulopalatopharyngoplasty (UPPP),radiofrequency ablation (RFA), and palatal implants.

Recommendations:

The presence and severity of obstructive sleep apnea must be determined before initiating surgical therapy (Standard). The patient should be advised about potential surgical success rates and complications, the availability of alternative treatment options such as nasal positive airway pressure and oral appliances, and the levels of effectiveness and success rates of these alternative treatments (Standard). The desired outcomes of treatment include resolution of the clinical signs and symptoms of obstructive sleep apnea and the normalization of sleep quality, the apnea-hypopnea index, and oxyhemoglobin saturation levels (Standard). Tracheostomy has been shown to be an effective single intervention to treat obstructive sleep apnea. This operation should be considered only when other options do not exist, have failed, are refused, or when this operation is deemed necessary by clinical urgency (Option). MMA is indicated for surgical treatment of severe OSA in patients who cannot tolerate or who are unwilling to adhere to positive airway pressure therapy, or in whom oral appliances, which are more often appropriate in mild and moderate OSA patients, have been considered and found ineffective or undesirable (Option). UPPP as a sole procedure, with or without tonsillectomy, does not reliably normalize the AHI when treating moderate to severe obstructive sleep apnea syndrome. Therefore, patients with severe OSA should initially be offered positive airway pressure therapy, while those with moderate OSA should initially be offered either PAP therapy or oral appliances (Option). Use of multi-level or stepwise surgery (MLS), as a combined procedure or as stepwise multiple operations, is acceptable in patients with narrowing of multiple sites in the upper airway, particularly if they have failed UPPP as a sole treatment (Option). LAUP is not routinely recommended as a treatment for obstructive sleep apnea syndrome (Standard). RFA can be considered as a treatment in patients with mild to moderate obstructive sleep apnea who cannot tolerate or who are unwilling to adhere to positive airway pressure therapy, or in whom oral appliances have been considered and found ineffective or undesirable (Option). Palatal implants may be effective in some patients with mild obstructive sleep apnea who cannot tolerate or who are unwilling to adhere to positive airway pressure therapy, or in whom oral appliances have been considered and found ineffective or undesirable (Option). Postoperatively, after an appropriate period of healing, patients should undergo follow-up evaluation including an objective measure of the presence and severity of sleep-disordered breathing and oxygen saturation, as well as clinical assessment for residual symptoms. Additionally, patients should be followed over time to detect the recurrence of disease (Standard).

Conclusions:

While there has been significant progress made in surgical techniques for the treatment of OSA, there is a lack of rigorous data evaluating surgical modifications of the upper airway. Systematic and methodical investigations are needed to improve the quality of evidence, assess additional outcome measures, determine which populations are most likely to benefit from a particular procedure or procedures, and optimize perioperative care.

Citation:

Aurora RN; Casey KR; Kristo D; Auerbach S; Bista SR; Chowdhuri S; Karippot A; Lamm C; Ramar K; Zak R; Morgenthaler TI. Practice parameters for the surgical modifications of the upper airway for obstructive sleep apnea in adults. SLEEP 2010;33(10):1408-1413.     

Effects of Continuous Positive Airway Pressure on Quality of Life in Patients With Moderate to Severe Obstructive Sleep Apnea: Data From a Randomized Controlled Trial

Study Objectives:

Previous studies have shown that CPAP has a substantial impact on daytime symptoms and quality of life (QOL). It remains unclear which outcome measures best identify real CPAP effects and carry independent information.

Methods:

One hundred-two men with moderate-severe obstructive sleep apnea were randomized to either “real” or “sham” CPAP for one month. Outcome measures were subjective sleepiness (Epworth Sleepiness Scale [ESS]) and QOL measures including SF-36/SF-12 and Calgary Sleep Apnea Quality of Life Index (SAQLI). The bed partner''s QOL and rating of patient''s response to CPAP were assessed with the Dublin questionnaire. All data were standardized using effect sizes and expressed as real minus sham to remove the nonspecific effects of placebo.

Results:

Real CPAP was superior to sham CPAP in almost all outcome measures. ESS, patient''s component from Dublin, and social interactions from SAQLI showed the largest differences in effect sizes between real and sham (1.33, 0.98, and 0.92 respectively). ESS carried the highest predictive power of real CPAP response (P < 0.0001, r² = 0.21). Question number 5 from Dublin (partner assessed patient''s sleep quality) and question 6 from ESS (dozing while talking) were the best single item predictors of real CPAP response.

Conclusions:

Real CPAP reduces subjective sleepiness and improves QOL of both patients and bed partners. ESS is the best score; question number 5 from Dublin and question number 6 from ESS are the best single item predictors of real CPAP response. This information should allow the selection of appropriate questions in clinical practice and research protocols.

Citation:

Siccoli MM; Pepperell JCT; Kohler M; Craig SE; Davies RJO; Stradling JR. Effects of continuous positive airway pressure on quality of life in patients with moderate to severe obstructive sleep apnea: data from a randomized controlled trial. SLEEP 2008;31(11):1551–1558.     

Oral appliance therapy reduces blood pressure in obstructive sleep apnea: a randomized, controlled trial

STUDY OBJECTIVE: To investigate the short-term effect (4 weeks) of oral appliance therapy for obstructive sleep apnea on blood pressure. DESIGN: Randomized, controlled, crossover trial. SETTING: Multidisciplinary sleep disorders clinic in a university teaching hospital. PATIENTS: Sixty-one patients diagnosed with obstructive sleep apnea on polysomnography (apnea hypopnea index > or = 10 per hour and at least 2 of the following symptoms--daytime sleepiness, snoring, witnessed apneas, fragmented sleep; age > 20 years; and minimum mandibular protrusion of 3 mm). INTERVENTION: A mandibular advancement splint (MAS) and control oral appliance for 4 weeks each. MEASUREMENTS AND RESULTS: Polysomnography and 24-hour ambulatory blood pressure monitoring were carried out at baseline and following each 4-week intervention period. Patients showed a 50% reduction in mean apnea hypopnea index with MAS compared with the control and a significant improvement in both minimum oxygen saturation and arousal index. There was a significant reduction with the MAS in mean (+/- SEM) 24-hour diastolic blood pressure (1.8 +/- 0.5 mmHg) compared with the control (P = .001) but not in 24-hour systolic blood pressure. Awake blood-pressure variables were reduced with the MAS by an estimated mean (+/- SEM) of 3.3 +/- 1.1 mmHg for systolic blood pressure (P = .003) and 3.4 +/- 0.9 mmHg for diastolic blood pressure (P < .0001). There was no significant difference in blood pressure measured asleep. CONCLUSION: Oral appliance therapy for obstructive sleep apnea over 4 weeks results in a reduction in blood pressure, similar to that reported with continuous positive airway pressure therapy.     

Effects of Exercise Training in Patients with Chronic Heart Failure and Sleep Apnea

Study Objectives:

To test the effects of exercise training on sleep and neurovascular control in patients with systolic heart failure with and without sleep disordered breathing.

Design:

Prospective interventional study.

Setting:

Cardiac rehabilitation and exercise physiology unit and sleep laboratory.

Patients:

Twenty-five patients with heart failure, aged 42 to 70 years, and New York Heart Association Functional Class I-III were divided into 1 of 3 groups: obstructive sleep apnea (n = 8), central sleep apnea (n = 9) and no sleep apnea (n = 7).

Interventions:

Four months of no-training (control) followed by 4 months of an exercise training program (three 60-minute, supervised, exercise sessions per week).

Measures and Results:

Sleep (polysomnography), microneurography, forearm blood flow (plethysmography), peak VO_2, and quality of life were evaluated at baseline and at the end of the control and trained periods. No significant changes occurred in the control period. Exercise training reduced muscle sympathetic nerve activity (P < 0.001) and increased forearm blood flow (P < 0.01), peak VO₂(P < 0.01), and quality of life (P < 0.01) in all groups, independent of the presence of sleep apnea. Exercise training improved the apnea-hypopnea index, minimum O₂ saturation, and amount stage 3-4 sleep (P < 0.05) in patients with obstructive sleep apnea but had no significant effects in patients with central sleep apnea.

Conclusions.

The beneficial effects of exercise training on neurovascular function, functional capacity, and quality of life in patients with systolic dysfunction and heart failure occurs independently of sleep disordered breathing. Exercise training lessens the severity of obstructive sleep apnea but does not affect central sleep apnea in patients with heart failure and sleep disordered breathing.

Citation:

Ueno LM; Drager LF; Rodrigues ACT; Rondon MUPB; Braga AMFW; Mathias W; Krieger EM; Barretto ACP; Middlekauff HR; Lorenzi-Filho G; Negrão CE. Effects of exercise training in patients with chronic heart failure and sleep apnea. SLEEP 2009;32(5):637-647.     

Incremental shuttle walk test in the assessment of patients with obstructive sleep apnea–hypopnea syndrome

Obstructive sleep apnea–hypopnea syndrome is associated independently with an increase in cardiovascular risk factors and is associated with self‐reported lack of exercise. We aimed to investigate the utility of the incremental shuttle walk test in routine clinical practice to monitor physical capacity of patients with obstructive sleep apnea–hypopnea syndrome and explore whether continuous positive airway pressure therapy alters exercise capacity. Participants with symptomatic moderate/severe obstructive sleep apnea–hypopnea syndrome attending for a trial of continuous positive airway pressure therapy completed questionnaires assessing sleepiness and physical activity and underwent an incremental shuttle walk test. Subjects compliant or partially compliant with continuous positive airway pressure therapy underwent reassessment at 2 weeks, 3 months and 6 months post‐initiation of therapy. Participants unable to tolerate continuous positive airway pressure therapy completed a single reassessment 6 months after their initial visit. Continuous positive airway pressure therapy resulted in an increased distance walked during the incremental shuttle walk test. Improvements in cardiovascular responses to exercise were identified. Compliant patients reported increased daily activity. The incremental shuttle walk test is a simple, reproducible and safe test that is responsive to continuous positive airway pressure treatment. Our findings support the use of the incremental shuttle walk test for monitoring the effects of continuous positive airway pressure treatment and may suggest its use in rehabilitation programmes designed to reduce obesity and cardiovascular risk factors in patients with obstructive sleep apnea–hypopnea syndrome.     

Continuous positive airway pressure reduces risk of motor vehicle crash among drivers with obstructive sleep apnea: systematic review and meta-analysis

Context:

Obstructive sleep apnea (OSA) is associated with an increased risk of motor vehicle crash.

Objective:

We performed a systematic review of the literature concerning the impact of continuous positive airway pressure (CPAP) treatment on motor vehicle crash risk among drivers with OSA. The primary objective was to determine whether CPAP use could reduce the risk of motor vehicle crash among drivers with OSA. A secondary objective involved determining the time on treatment required for CPAP to improve driver safety.

Data Sources:

We searched seven electronic databases (MEDLINE, PubMed (PreMEDLINE), EMBASE, PsycINFO, CINAHL, TRIS, and the Cochrane library) and the reference lists of all obtained articles.

Study Selection:

We included studies (before-after, case-control, or cohort) that addressed the stated objectives. We evaluated the quality of each study and the interplay between the quality, quantity, robustness, and consistency of the evidence. We also tested for publication bias.

Data Extraction:

Data were extracted by two independent analysts. When appropriate, data were combined in a fixed or random effects meta-analysis.

Results:

A meta-analysis of 9 observational studies examining crash risk of drivers with OSA pre- vs. post-CPAP found a significant risk reduction following treatment (risk ratio = 0.278, 95% CI: 0.22 to 0.35; P < 0.001). Although crash data are not available to assess the time course of change, daytime sleepiness improves significantly following a single night of treatment, and simulated driving performance improves significantly within 2 to 7 days of CPAP treatment.

Conclusions:

Observational studies indicate that CPAP reduces motor vehicle crash risk among drivers with OSA.

Citation:

Tregear S; Reston J; Schoelles K; Phillips B. Continuous positive airway pressure reduces risk of motor vehicle crash among drivers with obstructive sleep apnea. SLEEP 2010;33(10):1373-1380.     

Relationship Between Surface Facial Dimensions and Upper Airway Structures in Obstructive Sleep Apnea

Study Objectives:

We hypothesized that the facial phenotype is closely linked to upper airway anatomy. The aim of this study was to investigate the relationship between surface facial dimensions and upper airway structures using magnetic resonance imaging (MRI) in subjects with obstructive sleep apnea (OSA).

Design:

Cohort study.

Setting:

Sleep investigation unit.

Patients:

Sixty-nine patients (apnea-hypopnea index ≥ 10/h) underwent MRI as part of a study of upper airway anatomy in oral appliance therapy.

Interventions:

Measurements of a range of surface facial dimensions and upper airway soft tissue volumes were performed on the MR images using image-analysis software. Pearson correlation analyses were performed.

Measurements and Results:

Significant correlations were identified between a number of surface facial dimensions and neck circumference. Significant positive correlations were demonstrated between surface facial dimensions (including facial widths, facial heights, nose width, interocular and intercanthal widths) and upper airway structures. The strongest associations were between the tongue volume and the midface width (r = 0.70, P < 0.001), and lower-face width (r = 0.60, P < 0.001). Surface facial dimensions in combination were also strong determinants for tongue volume (r² = 0.69). Correlations between surface soft tissue thickness and upper airway soft tissue volumes occurred at the level of the midface but not at the level of the lower face.

Conclusions:

This study demonstrates that there is a relationship between surface facial dimensions and upper airway structures in subjects with OSA. These findings support the potential role of surface facial measurements in anatomic phenotyping for OSA.

Citation:

Lee RWW; Sutherland K; Chan ASL; Zeng B; Grunstein RR; Darendeliler MA; Schwab RJ; Cistulli PA. Relationship between surface facial dimensions and upper airway structures in obstructive sleep apnea. SLEEP 2010;33(9):1249-1254.     

A negative expiratory pressure test during wakefulness for evaluating the risk of obstructive sleep apnea in patients referred for sleep studies

OBJECTIVE:

Obstructive sleep apnea is characterized by increased upper airway collapsibility during sleep. The present study investigated the use of the negative expiratory pressure test as a method to rule out obstructive sleep apnea.

METHODS:

Flow limitation was evaluated in 155 subjects. All subjects underwent a diurnal negative expiratory pressure test and a nocturnal sleep study. The severity of sleep apnea was determined based on the apnea-hypopnea index. Flow limitation was assessed by computing the exhaled volume at 0.2, 0.5, and 1.0 s (V_0.2, V_0.5, and V_1.0, respectively) during the application of a negative expiratory pressure and expressed as a percentage of the previous exhaled volume. Receiver-operating characteristic curves were constructed to identify the optimal threshold volume at 0.2, 0.5, and 1.0 s for obstructive sleep apnea detection.

RESULTS:

Mean expiratory volumes at 0.2 and 0.5 s were statistically higher (p<0.01) in healthy subjects than in all obstructive sleep apneic groups. Increasing disease severity was associated with lower expiratory volumes. The V_0.2 (%) predictive parameters for the detection of sleep apnea were sensitivity (81.1%), specificity (93.1%), PPV (98.1%), and NPV (52.9%). Sensitivity and NPV were 96.9% and 93.2%, respectively, for moderate-to-severe obstructive sleep apnea, and both were 100% for severe obstructive sleep apnea.

CONCLUSION:

Flow limitation measurement by V_0.2 (%) during wakefulness may be a very reliable method to identify obstructive sleep apnea when the test is positive and could reliably exclude moderate and severe obstructive sleep apnea when the test is negative. The negative expiratory pressure test appears to be a useful screening test for suspected obstructive sleep apnea.     

Effects and Side-Effects of Surgery for Snoring and Obstructive Sleep Apnea – A Systematic Review

Study Objectives:

Many patients undergo surgery for snoring and sleep apnea, although the efficacy and safety of such procedures have not been clearly established. Our aim was systematically to review studies of the efficacy and adverse effects of surgery for snoring and obstructive sleep apnea.

Design:

Systematic review.

Measurements:

PubMed and Cochrane databases were searched in September 2007. Randomized controlled trials of surgery vs. sham surgery or conservative treatment in adults, with daytime sleepiness, quality of life, apnea-hypopnea index, and snoring as outcomes were included. Observational studies were also reviewed to assess adverse effects. Evidence of effect required at least two studies of medium and high quality reporting the same result.

Results:

Four studies of benefits and 45 studies of adverse effects were included. There was no significant effect on daytime sleepiness and quality of life after laser-assisted uvulopalatoplasty and radiofrequency ablation. The apnea-hypopnea index and snoring was reduced in one trial after laser-assisted uvulopalatoplasty but not in another trial. Subjective snoring was reduced in one trial after radiofrequency ablation. No trial investigating the effect of any other surgical modality met the inclusion criteria. Persistent side-effects occurred after uvulopalatopharyngoplasty and uvulopalatoplasty in about half the patients and difficulty in swallowing, globus sensation and voice changes were especially common.

Conclusions:

Only a small number of randomized controlled trials with a limited number of patients assessing some surgical modalities for snoring or sleep apnea are available. These studies do not provide any evidence of effect from laser-assisted uvulopalatoplasty or radiofrequency ablation on daytime sleepiness, apnea reduction, quality of life or snoring. We call for research of randomized, controlled trials of surgery other than uvulopalatopharyngoplasty and uvulopalatoplasty, as they are related to a high risk of long-term side-effects, especially difficulty swallowing.

Citation:

Franklin KA; Anttila H; Axelsson S; Gislason T; Maasilta P; Myhre KI; Rehnqvist N. Effects and side-effects of surgery for snoring and obstructive sleep apnea – a systematic review. SLEEP 2009;32(1):27–36.