Initial Apnea-hypopnea Index Research Articles

Home set-up polysomnography in the assessment of suspected obstructive sleep apnea

Home set-up polysomnography (PSG) has advantages over other portable monitoring devices, but remains unendorsed by professional bodies despite excellent utility in the Sleep Heart Health Study (SHHS). The study aims to determine technical reliability and diagnostic accuracy of unattended, home set-up versus attended laboratory-based PSG in patients with suspected obstructive sleep apnea (OSA). Thirty patients with suspected OSA without significant co-morbidity were recruited. After initial lab-PSG (Compumedics S series), patients underwent home set-up PSG (Compumedics Siesta) and lab-based PSG in random order. Studies were compared for study success, signal loss and likelihood ratio for OSA diagnosis [apnea-hypopnea index (AHI) >10]. Thirty subjects (mean age 49±13.8 years, body mass index 31±6.1 kg m(-2) ) completed investigations. SHHS technical acceptability criteria were met by all lab-based PSGs and 90% of home-based PSGs (93% clinically acceptable). Signal loss was higher at home (P=0.008). Sleep efficiency was similar between sites, but more preferred home-based PSG (50%). ancova revealed AHI was significantly different if initial AHI >26 per h (P=0.006), with an average underestimate of 5.1 per h at home. In technically acceptable studies the likelihood ratios to 'rule in' and 'rule out' OSA were 8.1 and 0.1, respectively. Unattended, home set-up PSG is technically reliable and achieves excellent diagnostic utility. Signal loss was higher at home but mitigated by multi-channel redundancy. Success rate was similar to SHHS and superior to laboratory set-up home studies. Home set-up PSG is a valid alternative to laboratory-based PSG for suspected OSA.

A Randomized Study on the Effect of Weight Loss on Obstructive Sleep Apnea Among Obese Patients With Type 2 Diabetes<subtitle>The Sleep AHEAD Study</subtitle><alt-title>Effect of Weight Loss on Obstructive Sleep Apnea</alt-title>

The belief that weight loss improves obstructive sleep apnea (OSA) has limited empirical support. The purpose of this 4-center study was to assess the effects of weight loss on OSA over a 1-year period. The study included 264 participants with type 2 diabetes and a mean (SD) age of 61.2 (6.5) years, weight of 102.4 (18.3) kg, body mass index (BMI) (calculated as weight in kilograms divided by height in meters squared) of 36.7 (5.7), and an apnea-hypopnea index (AHI) of 23.2 (16.5) events per hour. The participants were randomly assigned to either a behavioral weight loss program developed specifically for obese patients with type 2 diabetes (intensive lifestyle intervention [ILI]) or 3 group sessions related to effective diabetes management (diabetes support and education [DSE]). The ILI participants lost more weight at 1 year than did DSE participants (10.8 kg vs 0.6 kg; P < .001). Relative to the DSE group, the ILI intervention was associated with an adjusted (SE) decrease in AHI of 9.7 (2.0) events per hour (P < .001). At 1 year, more than 3 times as many participants in the ILI group than in the DSE group had total remission of their OSA, and the prevalence of severe OSA among ILI participants was half that of the DSE group. Initial AHI and weight loss were the strongest predictors of changes in AHI at 1 year (P < .01). Participants with a weight loss of 10 kg or more had the greatest reductions in AHI. Physicians and their patients can expect that weight loss will result in significant and clinically relevant improvements in OSA among obese patients with type 2 diabetes. Trial Registration clinicaltrials.gov Identifier: NCT00194259.

Effectiveness of Pillar palatal implants for snoring management

Determine patient factors associated with the success and complications of using the Pillar palatal implants for snoring management. Retrospective series of 79 consecutive adult patients receiving Pillar implants for snoring management between January 2005 and December 2007. Multiple regression analysis was used to determine factors associated with initial and final bed partner satisfaction with the snoring result, and factors associated with Pillar-related complications. A total of 64 of 79 (81%) bed partners reported snoring improvement in patients after initial Pillar implantation; however, only 31 (39%) were satisfied with the level of reduction. Following secondary procedures, the number of satisfied bed partners improved to 52 (66%). Factors associated with final bed partner satisfaction included lower initial apnea-hypopnea index (AHI) (P = 0.029), Friedman tongue position I or II (P = 0.008), and shorter follow-up time (P = 0.001). Sixteen patients (20%) experienced procedure-related complications. Factors associated with Pillar complications included female gender (P = 0.001) and placement under general anesthesia (P = 0.009). Initial AHI values and tongue position scores are important determinants of final snoring success. Pillar implants placed in women and under general anesthesia may have a higher risk of poor placement and extrusion.

Adaptive Servoventilation Versus Noninvasive Positive Pressure Ventilation For Central, Mixed, And Complex Sleep Apnea Syndromes

Although continuous positive airway pressure (CPAP) is most often effective in patients with obstructive sleep apnea, optimal treatment of patients with predominantly mixed apneas, central sleep apnea syndrome/Cheyne-Stokes respiration (CSA/CSR), or complex sleep apnea (CompSAS) is less straightforward, and may require alternative ventilatory assist modalities. To compare the efficacy of noninvasive positive pressure ventilation (NPPV) with adaptive servoventilation (ASV) in treating patients with centrally mediated breathing abnormalities. We hypothesized that NPPV and ASV would be equivalently efficacious in improving the apnea/hypopnea index (AHI) and respiratory arousal index (RAI). Prospective randomized crossover clinical trial comparing NPPV with ASV in patients with CSA/CSR, predominantly mixed apneas, and CompSAS in an acute setting. 21 patients (6 with CSA/CSR, 6 with predominantly mixed apneas, and 9 with CompSAS) with initial diagnostic AHI +/- standard deviation 51.9 +/- 22.8/hr and RAI 45.5 < or = 26.5/hr completed the study. Following optimal titration with CPAP (N = 15), disturbed breathing and disturbed sleep remained high with mean AHI = 34.3 +/- 25.7 and RAI = 32.1 +/- 29.7. AHI and RAI were markedly reduced with both NPPV (6.2 +/- 7.6 and 6.4 +/- 8.2) and ASV (0.8 +/- 2.4 and 2.4 +/- 4.5). Treatment AHI and RAI were both significantly lower using ASV (P < 0.01). These data confirm that in patients with CSA/CSR, mixed apneas, and CompSAS, both NPPV and ASV are effective in normalizing breathing and sleep parameters, and that ASV does so more effectively than NPPV in these types of patients.

Sleep-Disordered Breathing and Acute Ischemic Stroke

Sleep-disordered breathing (SDB) is frequent in stroke patients. Risk factors, treatment response, short-term and long-term outcome of SDB in stroke patients are poorly known. We prospectively studied 152 patients (mean age 56+/-13 years) with acute ischemic stroke. Cardiovascular risk factors, Epworth sleepiness score (ESS), stroke severity/etiology, and time of stroke onset were assessed. The apnea-hypopnea index (AHI) was determined 3+/-2 days after stroke onset and 6 months later (subacute phase). Continuous positive airway pressure (CPAP) treatment was started acutely in patients with SDB (AHI > or =15 or AHI > or =10+ESS >10). CPAP compliance, incidence of vascular events, and stroke outcome were assessed 60+/-16 months later (chronic phase). Initial AHI was 18+/-16 (> or =10 in 58%, > or =30 in 17% of patients) and decreased in the subacute phase (P<0.001). Age, diabetes, and nighttime stroke onset were independent predictors of AHI (r2=0.34). In patients with AHI > or =30, age, male gender, body mass index, diabetes, hypertension, coronary heart disease, ESS, and macroangiopathic etiology of stroke were significantly higher/more common than in patients with AHI <10. Long-term incidence of vascular events and stroke outcome were similar in both groups. CPAP was started in 51% and continued chronically in 15% of SDB pts. Long-term stroke mortality was associated with initial AHI, age, hypertension, diabetes, and coronary heart disease. SDB is common particularly in elderly stroke male patients with diabetes, nighttime stroke onset, and macroangiopathy as cause of stroke; it improves after the acute phase, is associated with an increased poststroke mortality, and can be treated with CPAP in a small percentage of patients.

Upper airway resistance syndrome: A long-term outcome study

This prospective study aimed to assess symptomatic evolution of patients diagnosed with Upper Airway Resistance Syndrome (UARS) four and half years after the initial UARS diagnosis. For this purpose, 138 UARS patients were contacted by mail between 43 and 69 months after the initial evaluation; 105 responded to the letter and 94 patients accepted to undergo new clinical and polysomnographic evaluations. Initial and follow-up polysomnographic recordings were scored using the same criteria. Results Of the 94 patients who completed the follow-up examination, none of them were using nasal CPAP. It was related to refusal by insurance providers to provide equipment based on initial apnea–hypopnea index (AHI) in 90/94 subjects. Percentage of patients with sleep related-complaints significantly increased over the four and half year period: daytime fatigue, insomnia and depressive mood increased by 12 to 20 times. Reports of sleep maintenance sleep onset insomnia and depressive mood was significantly increased. Hypnotic, antidepressant and stimulant prescription increased from initial to follow-up visit (from 11.7% to 61.7%; from 3.2% to 25.5% and from 0% to 9.6%, respectively) with antidepressant given as much for sleep disturbance as mood disorder. The polysomnography results at follow-up showed that 5 subjects had AHI compatible with Obstructive Sleep Apnea Syndrome (OSAS) but overall, respiratory disturbance index had no significant change. Total sleep time was significantly reduced compared to initial visit. Conclusions Many UARS patients remained untreated following initial evaluation. Worsening of symptoms of insomnia, fatigue and depressive mood were seen with absence of treatment of UARS.

Effective Compliance during the First 3 Months of Continuous Positive Airway Pressure

Effective compliance (time spent at the effective pressure) with nasal CPAP in obstructive sleep apnea has been reported to be poor. The aim of our study was to evaluate effective compliance in a large European multicenter study. One hundred twenty-one consecutive newly treated patients (initial apnea-hypopnea index [AHI] = 62.0 +/- 29. 5/h, AHI under CPAP = 6.4 +/- 8.1/h, CPAP pressure = 8.7 +/- 2.6 cm H(2)O, BMI = 33.1 +/- 6.8 kg/m(2)) were randomly allocated to a group with (MC(+)) (n = 58) or without (MC(-)) (n = 63) a control unit measuring effective compliance at 1, 2, and 3 mo, which was compared with the built-in time counter data. MC(+) data were 94 +/- 10, 98 +/- 5, and 96 +/- 9% of counter data at 1, 2, and 3 mo, respectively. Using criteria of regular use already reported in the literature (at least 4 h of nCPAP per day of use and nCPAP administered more than 70% of the days) we found 77, 82, and 79% compliant patients at 1, 2, and 3 mo, respectively, 79% of the patients meeting these criteria each month. Although there were no pulmonary functions or polysomnographic differences between the two subgroups, the compliant patients did report a greater improvement in minor symptoms. We found a close correlation between effective use of CPAP and the machine run time. The main result of our study was a higher effective compliance than previously reported, approximately 80% of the patients being regular users versus 46% in a previously published study. This may result from different technical and medical follow-up.

Upper Airway Changes in Snorers and Mild Sleep Apnea Sufferers After Uvulopalatopharyngoplasty (UPPP)

We used upper airway (UA) imaging in 20 patients to determine (1) whether an effective enlargement of the UA is obtained after uvulopalatopharyngoplasty (UPPP), and (2) whether UA modifications explain the results of such surgery. Cephalometric measurements were made to assess the posterior airway space, the length and width of the soft palate, and the distance between the hyoid bone and the mandibular plane. Pharyngeal CT measured the airway cross-sectional area (CSA) at each 10-mm slice from 10 mm above (-10) to 40 mm below (+40) the hard palate. Polysomnography was performed before and after surgery (10+/-10 [SD] months). Good responders were defined by an apnea-hypopnea index (AHI) of <10 postsurgery or, in patients in whom AHI was initially <10, a reduction of AHI >50% of the initial AHI. Twenty patients (age=45+/-11 years) were studied. For the whole group, the mean body mass index (26+/-4 kg/m2) and AHI (14+/-13 vs 18+/-16/h) were unchanged after UPPP. The results of the surgery were mediocre with 7 good responders (35%) and 13 nonresponders (65%) defined by polysomnographic criteria. The only changes on UA imaging for the group as a whole after UPPP were decrease in length (40+/-6 vs 29+/-5 mm, p< or =0.0006) and increase in width of the soft palate (11.5+/-2.7 vs 13.6+/-3.5 mm, p< or =0.006). The increase or decrease in minimal CSA at the oropharyngeal (OP) level after UPPP was significantly correlated with the change in AHI (r=-0.54, p<0.02). Moreover, the changes in CSA obtained at the OP level were significant only in the patients who responded favorably to UPPP (7 vs 13 nonresponders). Postoperative OP enlargement is associated with a good outcome of UPPP. Persistent narrowing in nonresponders could be due to the increase in soft palate width after surgery.