Uvulopalatopharyngoplasty may compromise nasal CPAP therapy in sleep apnea syndrome

Predictors for short-term and long-term automatic PAP compliance

STUDY OBJECTIVES

Positive airway pressure (PAP) is considered a standard treatment for obstructive sleep apnea (OSA), but there are compliance issues. As compliance to PAP tends to decrease with time, it is necessary to consider reasons affecting compliance at each period. Therefore, this study aimed to define factors affecting short-term and long-term compliance to PAP therapy.

METHODS

One hundred eighty-seven patients with OSA who started PAP treatment between July 2018 to March 2020 were included. Acceptance and compliance rates were monitored. Demographics, polysomnography (PSG) profiles, cephalometric data, and physical examination results were analyzed to identify factors predictive of PAP compliance at short-term (3 months) and long-term (12 months) periods.

RESULTS

The acceptance rate of PAP was 92.5%. Compliance at 3 months and 12 months was 79.1% and 51.3%, respectively. Higher apnea-hypopnea index (odds ratio [OR] 1.018, P = .049) and older age (OR 1.032, P = .039) were predictive factors of good automatic PAP (APAP) compliance at 3 months. However, long-term compliance was affected by the percentage of duration with O2 desaturation of < 90% (CT90; OR 1.032, P = .011) and baseline self-reported symptom scores such as nasal obstruction (OR 0.819, P = .038) and awakening (OR 0.796, P = .045).

CONCLUSIONS

In PAP use, indicators of OSA severity such as apnea-hypopnea index affect short-term compliance. On the other hand, the mandibular plane to hyoid distance and self-reported symptoms such as nasal obstruction and awakening can affect long-term compliance.

CITATION

Park SI, Kim BK, Lee KE, Hong SD, Jung YG, Kim HY. Predictors for short-term and long-term automatic PAP compliance. J Clin Sleep Med. 2023;19(1):17-26.

One-Stage Multilevel Surgery for Treatment of Obstructive Sleep Apnea Syndrome

We report the results of one-stage multilevel upper airway surgery for patients who could not tolerate continuous positive airway pressure (CPAP). Patients treated with multilevel surgery at a University Hospital in 2015–2019 were identified from a prospectively maintained database. The inclusion criteria were aged 18–70 years, body mass index (BMI) < 35 kg/m², apnea–hypopnea index (AHI) > 20, and lingual tonsil hypertrophy grade 3 or 4. Drug-induced sleep endoscopy was performed before surgery in all patients. Multilevel surgery was performed in one stage and included expansion sphincter pharyngoplasty (ESP), coblation tongue base reduction (CTBR), and partial epiglottectomy (PE) as required. The outcome measures were postoperative AHI, time percentage oxygen saturation < 90%, and Epworth Sleepiness Scale (ESS) score. A total of 24 patients were included: median age 49.1 years, average BMI 27.26 kg/m², and 90% men. Ten patients received ESP plus CTBR plus PE, eight received ESP plus CTBR, and six received ESP plus PE. The mean preoperative AHI was 33.01 at baseline and improved to 17.7 ± 13 after surgery (p < 0.05). The ESS score decreased from 11 ± 5.11 to 7.9 ± 4.94 (p < 0.05). The surgical success rate according to Sher’s criteria was 82.3%. The median follow-up was 23.3 months (range 12–36). These findings suggest that multilevel surgery is a safe and successful treatment of OSAHS.

Surgical management of obstructive sleep apnoea: A position statement of the Australasian Sleep Association. Respirology 2020;25:1292-1308. [PMID: 33190389 PMCID: PMC7839593 DOI: 10.1111/resp.13967]

Surgery for adult obstructive sleep apnoea (OSA) plays a key role in contemporary management paradigms, most frequently as either a second‐line treatment or in a facilitatory capacity. This committee, comprising two sleep surgeons and three sleep physicians, was established to give clarity to that role and expand upon its appropriate use in Australasia. This position statement has been reviewed and approved by the Australasian Sleep Association (ASA) Clinical Committee.

Effect of Multilevel Upper Airway Surgery vs Medical Management on the Apnea-Hypopnea Index and Patient-Reported Daytime Sleepiness Among Patients With Moderate or Severe Obstructive Sleep Apnea: The SAMS Randomized Clinical Trial

IMPORTANCE

Many adults with obstructive sleep apnea (OSA) use device treatments inadequately and remain untreated.

OBJECTIVE

To determine whether combined palatal and tongue surgery to enlarge or stabilize the upper airway is an effective treatment for patients with OSA when conventional device treatment failed.

DESIGN, SETTING, AND PARTICIPANTS

Multicenter, parallel-group, open-label randomized clinical trial of upper airway surgery vs ongoing medical management. Adults with symptomatic moderate or severe OSA in whom conventional treatments had failed were enrolled between November 2014 and October 2017, with follow-up until August 2018.

INTERVENTIONS

Multilevel surgery (modified uvulopalatopharyngoplasty and minimally invasive tongue volume reduction; n = 51) or ongoing medical management (eg, advice on sleep positioning, weight loss; n = 51).

MAIN OUTCOMES AND MEASURES

Primary outcome measures were the apnea-hypopnea index (AHI; ie, the number of apnea and hypopnea events/h; 15-30 indicates moderate and >30 indicates severe OSA) and the Epworth Sleepiness Scale (ESS; range, 0-24; >10 indicates pathological sleepiness). Baseline-adjusted differences between groups at 6 months were assessed. Minimal clinically important differences are 15 events per hour for AHI and 2 units for ESS.

RESULTS

Among 102 participants who were randomized (mean [SD] age, 44.6 [12.8] years; 18 [18%] women), 91 (89%) completed the trial. The mean AHI was 47.9 at baseline and 20.8 at 6 months for the surgery group and 45.3 at baseline and 34.5 at 6 months for the medical management group (mean baseline-adjusted between-group difference at 6 mo, -17.6 events/h [95% CI, -26.8 to -8.4]; P < .001). The mean ESS was 12.4 at baseline and 5.3 at 6 months in the surgery group and 11.1 at baseline and 10.5 at 6 months in the medical management group (mean baseline-adjusted between-group difference at 6 mo, -6.7 [95% CI, -8.2 to -5.2]; P < .001). Two participants (4%) in the surgery group had serious adverse events (1 had a myocardial infarction on postoperative day 5 and 1 was hospitalized for observation following hematemesis of old blood).

CONCLUSIONS AND RELEVANCE

In this preliminary study of adults with moderate or severe OSA in whom conventional therapy had failed, combined palatal and tongue surgery, compared with medical management, reduced the number of apnea and hypopnea events and patient-reported sleepiness at 6 months. Further research is needed to confirm these findings in additional populations and to understand clinical utility, long-term efficacy, and safety of multilevel upper airway surgery for treatment of patients with OSA.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry: ACTRN12614000338662.

Continuous positive airway pressure therapy in obstuctive sleep apnea: benefits and alternatives

INTRODUCTION

Obstructive sleep apnea (OSA) is a highly prevalent condition affecting persons of all age with an increasing public health burden. It is implicated in cardiovascular disease, metabolic syndrome, neurocognitive impairment, reductions in quality of life, and increased motor vehicle accidents. The goals of OSA treatment are to improve sleep and daytime symptoms, and minimize cardiovascular risks.Areas covered: Continuous positive airway pressure (CPAP) is considered the gold standard therapy that delivers pressurized air into the upper airway to relieve obstruction during sleep. Although CPAP is an effective modality of treatment for OSA, adherence to therapy is highly variable. This article highlights the benefits of CPAP therapy, along with alternative treatment options including oral appliance, implantable and wearable devices, and surgery. Expert commentary: CPAP therapy is the gold standard treatment option and should continue to be offered to those who suffer from OSA. Alternative options are available for those who are unable to adhere to CPAP or choose an alternative treatment modality. The most interesting advances have been incorporating orthodontic procedures in conjunction with myofunctional therapy in prepubertal children, raising the possibility of OSA prevention by initiating treatment early in life.

Upper Airway Variation and Frequent Alcohol Consumption Can Affect Compliance With Continuous Positive Airway Pressure

Objectives

Compliance with continuous positive airway pressure (CPAP) treatment remains a primary concern for improving treatment outcomes of obstructive sleep apnea. There are few studies that have considered the role of upper airway anatomy on the compliance with CPAP. We hypothesized that upper airway anatomy would influence the compliance with CPAP.

Methods

One hundred out of 161 consecutive patients were enrolled in this study. The following possible determinants were tested against CPAP use: demographic and anthropometric data, minimal cross-sectional area on acoustic rhinometry, cephalometric and polysomnographic data, questionnaires of Epworth sleepiness scale and Beck depression index, and histories of previous upper airway surgery, degree of nasal obstruction, daily cigarette consumption, and weekly frequency of alcohol intake.

Results

Univariate analysis showed that histories of previous upper airway surgery and less frequent alcohol consumption, and longer mandibular plane-hyoid length (MP-H) on cephalometry were associated with longer average daily CPAP use. After adjustment for the confounding factors with multiple linear regression analysis, alcohol consumption and MP-H were still associated with the compliance with CPAP significantly.

Conclusion

To improve compliance with CPAP, careful evaluations of upper airway problems and life style are important before initiating CPAP.

The Effect of Upper Airway Surgery on Continuous Positive Airway Pressure Levels and Adherence: A Systematic Review and Meta-Analysis

Background /Aims: The aim of this study was to determine the effect of upper airway surgery (UAS) on continuous positive airway pressure (CPAP). A secondary objective was to determine if a decrease in CPAP from UAS increases CPAP adherence.

METHODS

Studies were eligible for inclusion if a CPAP titration was performed both prior and following UAS in patients with obstructive sleep apnea (OSA). Studies that compared adherence to CPAP before and after UAS were included to evaluate the secondary objective.

RESULTS

A total of 11 articles involving 323 patients were included in the review. The results show that there was a mean reduction in CPAP of 1.40 cm H2O (95% CI -2.08 to -0.73). Four of the 11 papers, with a total of 80 patients, evaluated CPAP adherence and found a significant 0.62-hour improvement on average (95% CI 0.22-1.01).

CONCLUSION

Due to high levels of nonadherence, surgical intervention will play a role even in patients who are unlikely to be fully cured by surgery. UAS decreases the apnea-hypopnea index and modestly reduces CPAP while improving CPAP adherence in the majority of patients. The evidence suggests that UAS may have an adjunctive role in the management of OSA.

The influence of multilevel upper airway surgery on CPAP tolerance in non-responders to obstructive sleep apnea surgery

The aim of this study was to evaluate the influence of multilevel upper airway surgery on subsequent continuous positive airway pressure (CPAP) use and tolerance in patients with moderate to severe obstructive sleep apnea (OSA). The study cohort enrolled 67 consecutive patients, who underwent septoplasty plus modified uvulopharyngopalatoplasty (mUPPP) with or without modified tongue base suspension (mTBS) due to CPAP intolerance, and who had residual OSA requiring CPAP therapy [non-responders to surgery, apnea-hypopnea index (AHI) >15 events/h] that had been confirmed by control polysomnography at the sixth month postoperatively. A questionnaire including questions on postoperative CPAP use, problems faced during CPAP use after the surgery, change in OSA symptoms, and satisfaction with the surgery was designed, and filled through interviews. Seventeen (25.4 %) patients had septoplasty plus mUPPP and 50 (74.6 %) had septoplasty plus mUPPP combined with mTBS. Postoperatively, mean AHI (45.00 ± 19.76 vs. 36.60 ± 18.34), Epworth sleepiness scale (ESS) score (18.00 ± 4.45 vs. 13.00 ± 4.72), oxygen desaturation index (ODI) (48.98 ± 16.73 vs. 37.81 ± 17.03), and optimal CPAP level (11.80 ± 1.40 vs. 8.96 ± 1.20) were decreased (p < 0.001 for all parameters). Fifty-nine percent of patients reported that they fairly satisfied with the surgery and 49.2 % reported that their symptoms were completely resolved. While none of the cases could tolerate CPAP before surgery, almost half (47.8 %) of the cases used CPAP without problems postoperatively. Postoperative CPAP users had significantly higher postoperative AHI (p = 0.001), supine AHI (p = 0.009), ESS (p = 0.019), and ODI (p = 0.014), and significantly lower postoperative minimum O2 saturation (p = 0.001) compared with non-users. Multilevel upper airway surgery with less invasive techniques may improve CPAP tolerance in well-selected patients.

New developments in the use of positive airway pressure for obstructive sleep apnea

Obstructive sleep apnea (OSA) is a disorder which afflicts a large number of individuals around the world. OSA causes sleepiness and is a major cardiovascular risk factor. Since its inception in the early 1980's, continuous positive airway pressure (CPAP) has emerged as the major treatment of OSA, and it has been shown to improve sleepiness, hypertension, and a number of cardiovascular indices. Despite its successes, adherence with treatment remains a major limitation. Herein we will review the evidence behind the use of positive airway pressure (PAP) therapy, its various modes, and the methods employed to improve adherence. We will also discuss the future of PAP therapy in OSA and personalization of care.

Obstructive sleep apnoea syndrome

Obstructive sleep apnoea syndrome (OSAS) is a common clinical condition in which the throat narrows or collapses repeatedly during sleep, causing obstructive sleep apnoea events. The syndrome is particularly prevalent in middle-aged and older adults. The mechanism by which the upper airway collapses is not fully understood but is multifactorial and includes obesity, craniofacial changes, alteration in upper airway muscle function, pharyngeal neuropathy and fluid shift towards the neck. The direct consequences of the collapse are intermittent hypoxia and hypercapnia, recurrent arousals and increase in respiratory efforts, leading to secondary sympathetic activation, oxidative stress and systemic inflammation. Excessive daytime sleepiness is a burden for the majority of patients. OSAS is also associated with cardiovascular co-morbidities, including hypertension, arrhythmias, stroke, coronary heart disease, atherosclerosis and overall increased cardiovascular mortality, as well as metabolic dysfunction. Whether treating sleep apnoea can fully reverse its chronic consequences remains to be established in adequately designed studies. Continuous positive airway pressure (CPAP) is the primary treatment modality in patients with severe OSAS, whereas oral appliances are also widely used in mild to moderate forms. Finally, combining different treatment modalities such as CPAP and weight control is beneficial, but need to be evaluated in randomized controlled trials. For an illustrated summary of this Primer, visit: http://go.nature.com/Lwc6te.

The effect of nasal surgery on continuous positive airway pressure device use and therapeutic treatment pressures: a systematic review and meta-analysis

BACKGROUND

The relationship between nasal surgery and its effect on continuous positive airway pressure (CPAP) device therapeutic treatment pressures and CPAP device use has not been previously systematically examined.

STUDY OBJECTIVES

To conduct a systematic review and meta-analysis evaluating the effect of isolated nasal surgery on therapeutic CPAP device pressures and use in adults with obstructive sleep apnea (OSA).

METHODS

MEDLINE, Scopus, Web of Science, and The Cochrane Library were searched through July 15, 2014. The MOOSE consensus statement and PRISMA statement were followed.

RESULTS

Eighteen studies (279 patients) reported CPAP data after isolated nasal surgery. Seven studies (82 patients) reported preoperative and postoperative mean therapeutic CPAP device pressures and standard deviations (SD), which reduced from 11.6 ± 2.2 to 9.5 ± 2.0 centimeters of water pressure (cwp) after nasal surgery. Pooled random effects analysis demonstrated a statistically significant pressure reduction, with a mean difference (MD) of -2.66 cwp (95% confidence interval (CI), -3.65 to -1.67); P < 0.00001. Eleven studies (153 patients) reported subjective, self-reported data for CPAP use; and a subgroup analysis demonstrated that 89.1% (57 of 64 patients) who were not using CPAP prior to nasal surgery subsequently accepted, adhered to, or tolerated it after nasal surgery. Objective, device meter-based hours of use increased in 33 patients from 3.0 ± 3.1 to 5.5 ± 2.0 h in the short term (<6 mo of follow-up).

CONCLUSION

Isolated nasal surgery in patients with OSA and nasal obstruction reduces therapeutic CPAP device pressures and the currently published literature's objective and subjective data consistently suggest that it also increases CPAP use in select patients.

Willingness score obtained after a short CPAP trial predicts CPAP use at 1 year

PURPOSE

To predict continuous positive airway pressure (CPAP) adherence at 1 year.

METHODS

We followed consecutive OSA patients scheduled for CPAP initiation for 1 year. Patients completed a self-efficacy questionnaire (5 = low, 25 = high score) before CPAP initiation. After CPAP initiation, we enquired about patients' satisfaction in CPAP trial and their eagerness and willingness to continue CPAP therapy (0 = unsatisfied, uneager, or refused CPAP; 100 = satisfied, eager, or willing to continue CPAP treatment).

RESULTS

Of the 580 patients we followed, 377 continued CPAP therapy beyond 1 year. A low willingness score (<50) was expressed by 77 patients but only 7 of them used CPAP >4 h daily at 1 year, yielding a specificity of 97 % in predicting CPAP failure. At 1 year, patients with a self-efficacy score >20, expressed prior to CPAP initiation, used CPAP more often than the patients with a score <20 (average use 4.4 ± 2.2 h vs. 3.7 ± 2.3 h, p<0.001).

CONCLUSIONS

A low score of willingness to continue CPAP therapy after a short trial predicts CPAP failure and poor CPAP adherence at 1 year.

The effect of uvula-preserving palatopharyngoplasty in obstructive sleep apnea on globus sense and positional dependency

Objectives

This study investigated the outcomes of uvula-preserving palatopharyngoplasty (UPPPP) in patients with obstructive sleep apnea syndrome (OSAS).

Methods

Twenty men with obstructive sleep apnea syndrome received the UPPPP operation at our institution. We measured symptom changes after UPPPP using a visual analog scale (VAS), and all patients were examined with polysomnography pre- and post-operatively. 'Surgical success' was defined as reduction in apnea-hypopnea index (AHI) to below 20 events per hour and more than 50% post-operative reduction.

Results

Snoring decreased significantly (6.7±2.3 to 3.7±2.9 on VAS, P=0.002) but the postoperative globus sense did not differ from that preoperatively (2.0±2.4 to 2.1±2.7 on VAS, P=0.79). Apnea and apnea-hypopnea indices were significantly reduced after UPPPP (34.7±20 to 24.2±17.2 events/hour, P=0.029). The surgical success rate was 40% regardless of Friedman stage. There was significant reduction in the AHI on supine sleep in both surgically successful and unsuccessful patient groups.

Conclusion

UPPPP may minimize postoperative globus sense and other complications, with a success rate comparable to that of previously reported surgical methods in OSAS patients. In addition, it may reduce the apnea-hypopnea index in the supine sleep position.

Surgical options for the treatment of obstructive sleep apnea

Obstructive sleep apnea (OSA) is a prevalent condition characterized by repetitive airway obstruction during sleep with associated increased morbidity and mortality. Although CPAP is the preferred treatment, poor compliance is common. Patients intolerant of conventional OSA medical treatment may benefit from surgical therapy to alleviate pharyngeal obstruction. Case series suggest that maxillomandibular advancement has the highest surgical efficacy (86%) and cure rate (43%). Soft palate surgical techniques are less successful, with uvulopalatopharyngoplasty having an OSA surgical success rate of 50% and cure rate of 16%. Further research is needed to more thoroughly assess clinical outcomes (eg, quality of life, morbidity), better identify key preoperative patient and clinical characteristics that predict success, and confirm long-term effectiveness of surgical modalities to treat OSA.

Alternatives to positive airway pressure for obstructive sleep apnea syndrome

Owing to the prevalence, the considerable risk of accidents and cardiovascular consequences, optimal treatment of obstructive sleep apnea syndrome is of crucial importance. However, many patients look for alternative conservative or surgical therapies to continuous positive airway pressure to avoid discomfort and local side-effects owing to the mask. Scientific data are lacking for most of the alternative methods. However, it has been proven that intra-oral appliances can reduce mild-to-moderate respiratory disturbances; the maxillo-mandibular osteotomy is efficient in the short- and long-term but is preferred in special situations such as craniofacial dysmorphias. Weight reduction and body positioning cannot be recommended as a single treatment for obstructive sleep apnea syndrome. Resections of muscular tissue within the soft palate have to be strictly avoided. Efficacy of gentle soft palate procedures is difficult to predict and often decreases in the years following this treatment. Multilevel surgery concepts are of increasing interest, although more data from prospective, controlled studies are needed.

[Guideline: Treatment of obstructive sleep apnea in adults]

The current guideline discusses conservative and surgical therapy of obstructive sleep apnea (OSA) in adults from the perspective of the ear, nose and throat specialist. The revised guideline was commissioned by the German Society of Ear-Nose-Throat, Head-Neck Surgery (DG HNO KHC) and compiled by the DG HNO KHC's Working Group on Sleep Medicine. The guideline was based on a formal consensus procedure according to the guidelines set out by the German Association of Scientific Medical Societies (AWMF) in the form of a"S2e guideline". Research of the literature available on the subject up to and including December 2008 forms the basis for the recommendations. Evaluation of the publications found was made according to the recommendations of the Oxford Centre for Evidence-Based Medicine (OCEBM). This yielded a recommendation grade, whereby grade A represents highly evidence-based studies and grade D those with a low evidence base.

Evidence of interrelated side effects with reduced compliance in patients treated with nasal continuous positive airway pressure

OBJECTIVES

Patients treated for obstructive sleep apnea syndrome (OSAS) with nasal continuous positive airway pressure (nCPAP) often have side effects and poor compliance. Our objectives were to explore their side effects when treated with nCPAP and to validate the association of a side effect syndrome with the outcomes of sleep quality, daytime sleepiness and nCPAP compliance.

METHODS

Prospective exploratory and subsequent validation study using questionnaires was performed in a tertiary-care sleep-disorders clinic. Consecutive patients with polysomnographic diagnosis and nCPAP titrations treated at least 3 months with single-pressure nCPAP were studied. In the first survey, 114 patients were questioned of whom 89 (78%) qualified for exploratory analysis. In the validation survey of 122 patients, 104 (85%) were studied. Subjects were interviewed and their nCPAP meters were queried.

RESULTS

In the first survey, 3 side effects were often found together and each found to be correlated to compliance: mouth leak with nCPAP, nasal congestion, and taking off the mask prematurely. In the validation study, 34% of participants met a syndrome definition with at least 2 of 3 major side effects. Mean (SD) compliance was lower in patients with the syndrome: 4.97 (1.98) vs. 6.42 (1.56) hours per night (p=0.0001). Poor sleep quality and lower satisfaction with nCPAP were associated with the syndrome.

CONCLUSIONS

The syndrome of mouth leak, taking off the nCPAP mask prematurely and nasal congestion is frequent in patients treated with nCPAP. This is associated with lower compliance and poor sleep quality.

Mouth breathing in obstructive sleep apnea prior to and during nasal continuous positive airway pressure

BACKGROUND

Patients with obstructive sleep apnea syndrome (OSAS) often complain of dryness of mouth and throat prior to and during nasal continuous positive airway pressure (nCPAP). It is believed that this is due to mouth breathing (MB). However, the association between mouth breathing and apneas/hypopneas and the effect of CPAP on MB has not been studied.

OBJECTIVES

The purpose of the present study was, therefore, to assess the frequency and duration of episodes of MB prior to and during treatment with nCPAP.

METHODS

MB was recorded prior to and during nCPAP with a closely fitting mouth mask connected to a pneumotachograph and nasal flow was measured via nasal prongs. MB episodes were expressed as the number of events divided by total sleep time x 60, to give the MB event index per hour of sleep. MB time divided by total sleep time x 60 was calculated in minutes to get the MB time index per hour of sleep.

PATIENTS

Eleven male patients with OSAS (mean age 57.9 +/- 8.3 years, body mass index 30.2 +/- 3.8) were recruited to the study.

RESULTS

Prior to nCPAP, the apnea/hypopnea index was 55.8 +/- 26 and decreased during nCPAP to 8.0 +/- 3.4. The lowest SaO2 measured was 82.9 +/- 4.7%, and increased to 87.5 +/- 2.7% under nCPAP. The mean nCPAP was 7.8 +/- 1.6 cm H2O. MB event index per hour of sleep decreased from 35.2 +/- 19.7 prior to treatment to 5.0 +/- 5.2 under nCPAP (p < 0.01). In 52.2 +/- 27.4% of obstructive respiratory events, MB started at the end of an apnea/hypopnea episode, decreasing to 8.5 +/- 12.5% with nCPAP treatment. MB time index per hour of sleep was reduced from 13.5 +/- 10.2 min prior to treatment to 4.6 +/- 5.5 min under nCPAP (p < 0.05).

CONCLUSIONS

In OSAS patients, MB episodes often appear at the termination of an apnea/hypopnea episode. In many cases, MB episodes can be markedly reduced by nCPAP treatment. When patients on nCPAP complain of dry mouth, appropriate measurements should be performed to verify MB.

Current trends in the treatment of obstructive sleep apnea

Obstructive sleep apnea (OSA) is a condition of partial or complete upper airway obstruction leading to increased resistance to airflow and potential cessation of breathing during sleep. Effective treatment of OSA is challenging and there has been greater recognition by the medical and dental disciplines. By understanding the rationale, indications, benefits, risks and success of the various treatment options available, clinicians will be able to make more informed treatment recommendations in patient management.

A neurotoxinological approach to the treatment of obstructive sleep apnoea

Current treatment approaches to the problem of obstructive sleep apnoea (OSA) have limitations. Specifically, invasive anatomical-based surgery and dental appliances typically do not alleviate obstruction at an acceptable rate, and compliance to continuous positive airway pressure (CPAP) devices is frequently suboptimal. Neurotoxinological treatment approaches are widespread in the field of medicine, but as yet have not been evaluated as a treatment for sleep-disordered breathing. In this review, it is argued that despite widespread recognition of the loss of upper airway (UA) muscular tone and/or reflexes in the expression of OSA, most treatment interventions to date have focused on anatomical principles alone. Several hypothesised neurotoxinological interventions aimed at either enhancing UA neuromuscular tone and/or reflexes are proposed, and some preliminary data is presented. Although in its early infancy, with considerable toxicity studies in animals yet to be done, a neurotoxinological approach to the problem of OSA holds promise as a future treatment, with the potential for both high effectiveness and patient compliance.

Influence of UPPP surgery on tolerance to subsequent continuous positive airway pressure in patients with OSAHS

To investigate the effect of uvlopalatopharyngoplasty (UPPP) on post-surgery continuous positive airway pressure (CPAP) treatment during sleep in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS). Thirty-one OSAHS patients after UPPP surgery were recruited and studied on for more than 12 months after the procedure. Among them, 24 patients were treated with classical UPPP (cUPPP), which removes all of uvula and part of the soft palate. Seven had modified UPPP (mUPPP), keeping part of the uvula. The control group was 31 years in age, body mass index (BMI) and apnea-hypopnea index (AHI) matched, and newly diagnosed OSAHS patients without prior treatment. A manual titration of CPAP was performed during both (NREM) and non-rapid eye movement (NREM) sleep in all 62 patients. Patients were asked to keep a supine position while sleeping during the test. When significant mouth air leakage occurred and/or titration worsened with an increase of CPAP pressure, the pressure level was considered as the highest CPAP (hCPAP) a patient can tolerate in that sleep stage. The CPAP machine used for titration could produce highest pressure at 20 cm H2O. There were 74% (23/31) of UPPP patients who had less than 50% decrease in AHI, and 84% (26/31) of the 31 patients still had AHI>15 (range 16-110) during post-operation polysomnography (PSG) test. Most of them need further CPAP therapy. All of the untreated OSAHS patients could tolerate 17-20 cm H2O of CPAP during sleep. None had severe mouth air leak before an optimal pressure was reached. In contrast, four in the surgery group failed to respond to CPAP treatment during both NREM and REM sleep and one more during REM sleep. All of the seven patients who had a mUPPP could tolerate CPAP. One of the three tested both before and after surgery failed in the CPAP treatment after surgery during REM sleep. UPPP may compromise nasal CPAP therapy in OSAHS, especially in procedures with greater resection of the soft palate.

Revised Uvulopalatopharyngoplasty with Uvula Preservation and Its Clinical Study

OBJECTIVES

A revised uvulopalatopharyngoplasty (UPPP) is reported for reducing the surgical complications without compromising the response.

METHODS AND MATERIALS

A new method of performing UPPP was designed, in which the uvula is preserved, but a larger portion of the soft palate is removed. This new procedure is called the 'revised UPPP with uvula preservation' (Han's UPPP or H-UPPP), the characteristics of which are as follows: complete preservation of the uvula; larger portion of the soft palate resected (with the levator palati and tensor palati remaining intact); the adipose tissue in the space of the velum palati is removed; the preserved uvula will become a 'normal' one by the contraction of scar tissue on both sides of the musculus palato-uvularis and the lower margin of the tensor palati. 68 cases of obstructive sleep apnea/hypopnea syndrome had been treated with H-UPPP between September 1998 and May 2001.

RESULTS

Polysomnography was performed for all 68 cases 6 months postoperatively with a surgical response of 69.12%, defined as a >50% reduction of the apnea-hypopnea index and <20 apneic pauses/h; no palatopharyngeal incompetency or palatopharyngeal stenosis. Anatomic measurements showed that the preserved uvula in H-UPPP begins to retract 2 weeks postoperatively, and the preserved uvula becomes 'normal' in 3-6 months.

CONCLUSIONS

These results suggest that H-UPPP is an effective surgery and produces fewer complications compared with the classic UPPP.

Surgery for obstructive sleep apnoea

BACKGROUND

Obstructive sleep apnoea/hypopnoea syndrome(OSAHS) is the periodic reduction or cessation of airflow during sleep. The syndrome is associated with loud snoring, disrupted sleep and observed apnoeas. Surgery for obstructive sleep apnoea/hypopnoea syndrome aims to alleviate symptoms of daytime sleepiness, improve quality of life, and reduce the signs of sleep apnoea recorded by polysomnography.

OBJECTIVES

The objective of this review was to assess the effects of any type of surgery for the treatment of the symptoms of obstructive sleep apnoea/hypopnoea syndrome in adults.

SEARCH STRATEGY

We searched the Cochrane Airways Group Specialised Register and reference lists of articles. We contacted experts in the field, research dissemination bodies and other Cochrane Review Groups. Searches were current as of July 2005.

SELECTION CRITERIA

Randomised trials comparing any surgical intervention for obstructive sleep apnoea/hypopnoea syndrome with other surgical or non-surgical interventions or no intervention.

DATA COLLECTION AND ANALYSIS

Two reviewers assessed electronic literature search results for possibly relevant studies. Characteristics and data from studies meeting the inclusion criteria were extracted and entered into RevMan 4.2.

MAIN RESULTS

In the 2005 update for this review eight studies (412 participants) of mixed quality met the inclusion criteria. Data from seven studies were eligible for assessment in the review. No data could be pooled. Uvulopalatopharyngoplasty (UPPP) versus conservative management (one trial): An un validated symptom score showed intermittent significant differences over a 12-month follow-up period. No differences in Polysomnography (PSG) outcomes were reported. Laser-assisted uvulopalatoplasty (LAUP) versus conservative management/placebo (two trials): One study recruited mixed a population, and separate data could not be obtained for this trial. In the other study no significant differences in Epworth scores or quality of life reported. A significant difference in favour of LAUP was reported in terms of apnoea hypopnoea index (AHI) and frequency and intensity of snoring. UPPP versus oral appliance (OA) (one trial): AHI was significantly lower with OA therapy than with UPPP. No significant differences were observed in quality of life. UPPP versus lateral pharyngoplasty (lateral PP) (one trial): No significant difference in Epworth scores, but a greater reduction in AHI with lateral PP was reported. Tongue advancement (mandibular osteotomy) + PPP versus tongue suspension + PPP (one trial): There was a significant reduction in symptoms in both groups, but no significant difference between the two surgery types. Complications reported with all surgical techniques included nasal regurgitation, pain and bleeding. These did not persist in the long term. An additional study assessed the effects of four different techniques. No data were available on between group comparisons. Multilevel temperature-controlled radiofrequency tissue ablation (TCRFTA) versus sham placebo and CPAP (one trial): There was an improvement in primary and secondary outcomes of TCRFTA over sham placebo and but no difference in symptomatic improvement when compared with CPAP.

AUTHORS' CONCLUSIONS

There are now a small number of trials assessing different surgical techniques with inactive and active control treatments. The studies assembled in the review do not provide evidence to support the use of surgery in sleep apnoea/hypopnoea syndrome, as overall significant benefit has not been demonstrated. The participants recruited to the studies had mixed levels of AHI, but tended to suffer from moderate daytime sleepiness where this was measured. Short-term outcomes are unlikely to consistently identify suitable candidates for surgery. Long-term follow-up of patients who undergo surgical correction of upper airway obstruction is required. This would help to determine whether surgery is a curative intervention, or whether there is a tendency for the signs and symptoms of sleep apnoea to re-assert themselves, prompting patients to seek further treatment for sleep apnoea.

Compliance with nasal CPAP in obstructive sleep apnea patients

Continuous positive airway pressure (CPAP) is currently the treatment of choice for the majority of patients with obstructive sleep apnea (OSA). After a CPAP trial, the initial acceptance rate is 70-80%. Patients who derive no subjective benefit from such a trial are poor candidates for home treatment with CPAP because they are likely to exhibit lower adherence and compliance rates. About 90% of OSA patients provided with CPAP apparatus will adhere to long-term CPAP treatment. Patients abandoning CPAP do so during the first few months of home therapy, a period during which close monitoring and support is warranted. Because of the strong correlation between the machine run time and effective pressure delivered at the nasal mask (90-95%), the time-counter of the CPAP device is sufficient to monitor compliance in clinical practice, allowing for early intervention in cases of suboptimal use. Longterm acceptors of CPAP display a satisfactory compliance (5-6.5 h of average daily use) which compares favourably with compliance with treatment in other chronic diseases. Lower acceptance and compliance rates have been reported in North America as compared to Europe. This could be related to cultural differences or different routines of prescription and follow-up.

Mouth breathing compromises adherence to nasal continuous positive airway pressure therapy

STUDY OBJECTIVES

Mouth leak compromises nasal continuous positive airway pressure (CPAP) therapy. We hypothesized that patients who breathe mainly through their mouths during sleep, compared to those who breathe mainly through their noses, would have more mouth leak during CPAP and therefore lower adherence to CPAP.

DESIGN

A case-control study to compare adherence to CPAP at 1 year in mouth breathers (MBs) with nose breathers (NBs).

SETTING

University teaching hospital with a sleep laboratory.

PATIENTS

Fifty-one CPAP-naive patients (4 women), with a respiratory disturbance index (RDI) > 15/h. Of the 51 patients, 30 patients breathed through their mouths (mouth breathing > 70% of total sleep time [TST]), and 21 patients breathed through their noses (mouth breathing < 30% of TST). MBs between 30% and 70% of TST were excluded.

INTERVENTIONS

Overnight polysomnography was performed at baseline, during CPAP titration, and at 3 months. Patients were followed up for 1 year after beginning CPAP.

MEASUREMENTS AND RESULTS

To measure mouth breathing, nasal and oral thermistors during polysomnography were separated by a 3 x 6-cm silicon transverse diaphragm. RDI decreased from (mean +/- SD) 37.8 +/- 21.5 to 1.8 +/- 2.6/h at 3 months. Throughout the study, adherence to CPAP (mean daily CPAP use in hours) was better in NBs. Most NBs (71%) but only 30% of MBs used CPAP daily for > 4 h at 1-year follow-up. Mouth breathing decreased significantly from 84 +/- 8.9% at baseline to 22 +/- 14.4% at 3 months.

CONCLUSION

Patients with moderate-to-severe sleep-disordered breathing and a high percentage of mouth breathing during sleep were less adherent to CPAP therapy than patients exhibiting a low percentage of mouth breathing.

A review of surgical treatment for obstructive sleep apnoea/hypopnoea syndrome

Surgical intervention and treatment of OSAHS and snoring has a considerable history, encompassing a number of operations all of which have the intention of reducing or by-passing the pharyngeal resistance that occurs during sleep. Review of the published literature presents some problems, however, due to the ethical difficulties of undertaking randomised controlled trials in surgery. Uncontrolled trials are less satisfactory due to the large 'regression to the mean' and placebo effects. However, there is a considerable body of literature available relating to surgical intervention.

Laser-assisted uvulopalatoplasty and tonsillectomy for the management of obstructive sleep apnea syndrome

OBJECTIVES/HYPOTHESIS

Laser-assisted uvulopalatoplasty (LAUP) is a widely accepted procedure for the management of snoring, but its role in the treatment of obstructive sleep apnea syndrome is currently unclear. The objective of the study was to evaluate the role of LAUP in treating moderate and severe obstructive sleep apnea syndrome.

STUDY DESIGN

Retrospective review of a surgical treatment protocol for obstructive sleep apnea syndrome.

METHODS

Between October 1993 and January 1999, 80 patients with moderate or severe obstructive sleep apnea syndrome and a significant component of retropalatal obstruction were treated with surgery at the Department of Otolaryngology at Northwestern University Medical School (Chicago, IL). Surgery consisted of LAUP with tonsillectomy (if tonsils were present) with the patient under general anesthesia or LAUP alone with local anesthesia (if the tonsils were absent). No patients received traditional uvulopalatopharyngoplasty. Sixty-four of the 80 patients underwent both preoperative and postoperative polysomnograms. Surgical "response" was defined as a 50% decrease in the apnea-hypopnea index (AHI) (the total number of apneic and hypopneic events per hour of sleep); surgical "cure" was defined as a 50% decrease in AHI and a final AHI of less than 20.

RESULTS

The surgical response rate was 59% (38 of 64 patients), and the surgical cure rate was 39% (25 of 64 patients). Twelve patients (18.8%) had a higher AHI after surgery. The AHI (mean +/- SD) changed significantly from 51.4 +/- 30.9 preoperatively to 26.3 +/- 20.8 on postoperative polysomnogram (P = 7.0 x 10-9). Laser-assisted uvulopalatoplasty alone was performed in 33 patients with a response rate of 61% and a cure rate of 42%. Laser-assisted uvulopalatoplasty with tonsillectomy was performed in 31 patients with a response rate of 58% and a cure rate of 35%. The overall incidence of nasopharyngeal insufficiency was 0%.

CONCLUSION

The results of the study suggested that LAUP with adjunctive tonsillectomy is an effective treatment for patients with obstructive sleep apnea syndrome and retropalatal obstruction with a lower complication rate than standard surgical therapy (uvulopalatopharyngoplasty).

Continuous positive airway pressure: new generations

Automatic positive airway pressure devices are the most technologically advanced positive airway pressure devices available for use in OSA. Although heterogeneous, they have in common the ability to detect and respond to changes in upper airway resistance. Data cannot necessarily be extrapolated from one device to another, and the field is rapidly advancing. Most studies of APAP have been performed in a supervised setting, or patients have been carefully selected to have a high likelihood of OSA uncomplicated by disorders such as alveolar hypoventilation or central apnea or technical problems such as mask leaks. Studies of APAP for the diagnosis of OSA have shown that APAP can diagnose severe OSA effectively, but the diagnosis of mild-moderate OSA is less reliable. APAP devices also can be effective therapy for selected patients with OSA, with overall similar results to conventional fixed CPAP in terms of respiratory disturbances, sleep quality, nocturnal oxygenation, and daytime sleepiness and performance, with less known or other long-term outcomes. In most studies, mean treatment pressures are lower, without change in side effect profile. Compliance and preference with APAP are similar to or somewhat better than CPAP in most studies. APAP also can be used in an attended setting to titrate an effective pressure for use in long-term conventional CPAP therapy, also with similar results to CPAP in many patients. APAP devices are more expensive than CPAP devices, but the cost may be outweighed if a group of patients who can be diagnosed, treated, or titrated safely in the unattended setting can be identified. Although diagnostic and therapeutic algorithms for APAP have been proposed, the best candidates for this modality must be defined better.

Evidence-based medicine in sleep apnea surgery

Since the first description of sleep apnea as a clinical entity, the understanding of it within the medical community has increased significantly. Much research has explored the causes, assessment, and treatment of this disease. This research has resulted in a variety of tools for assessment and approaches to treatment. As research progresses, new data have shed light on the strengths of traditional approaches and their limitations. This article gives background for current approaches and charts a potential future course for sleep apnea assessment and treatment.

Sleep studies for sleep apnoea

Sleep studies have grown to encompass a broad range of technologies employed to study and diagnose a variety of sleep disorders. From their inception in neurophysiology laboratories interested in investigating primary disorders of sleep architecture from psychiatric illness, their remit has widened such that their most common role is currently to diagnose secondary sleep disruption from respiratory, cardiovascular or other systemic causes. This review outlines the pathophysiology of obstructive sleep apnoea in particular and how sleep studies have improved our understanding of the complex dynamic changes in blood gas tensions, cardiovascular control and cerebral arousal that occur with these repetitive events. We review the historical development of standard laboratory-based sleep studies and discuss their limitations in staging sleep, reflecting the episodes of increased upper airway resistance that underlie these disorders and their ability to predict individuals' symptoms or response to medical or surgical therapies. We then describe some alternative signals that have been employed to monitor the physiological changes in upper airway resistance and arousal with a discussion of some of the evidence that these 'limited' studies may provide diagnostic information that can guide clinical decision making and may predict the outcome without the need, in some cases, for more complex and costly laboratory-based studies.

UPPP or LAUP: Is This All Surgeons Should Talk About?

Snoring is a nuisance at least! The inspiratory vibrations of pharyngeal soft tissue may exceed 85 dB. For thousands of years snoring has led to social and marital disharmony in many cases. The treatment of the symptom snoring has been of interest for the medical profession for the same time. Today, we know that snoring is the most common presenting symptom of obstructive sleep apnea (OSA). The wider recognition of OSA and its impact on the development of systemic and pulmonary hypertension, cardiac arrhythmias, heart failure and daytime sleepiness has occurred in the last decade. The treatment of OSA has become a medical issue apart from its social aspects.

Predictive factors for the need for additional humidification during nasal continuous positive airway pressure therapy

OBJECTIVE

To identify potential risk factors for the need for an additional cold or heated humidifier in nasal continuous positive airway pressure (nCPAP) circuitry.

DESIGN

A prospective cohort study.

SETTING

University hospital sleep-disorders center.

PATIENTS

Eighty-two consecutive patients with obstructive sleep apnea syndrome were followed up for a median of 347 days (range, 3 to 530 days) after the initiation of nCPAP therapy.

MEASUREMENTS AND RESULTS

In 46 patients (56%), the occurrence of upper-airway symptoms led to the addition of a cold humidifier after a median time of 39 days (range, 2 to 94 days). In 23 of the 46 patients, the persistence of the symptoms indicated the secondary use of a heated humidifier after a median time of 28 days (range, 5 to 70 days). nCPAP use (mean +/- SD) was not influenced by cold humidification (4.58 +/- 2.05 h/d vs 4.7 +/- 2.48 h/d; p = 0.75), but it increased significantly with heated humidification (5.38 +/- 2.26 h/d vs 3.51 +/- 2.53 h/d; p < 0.01). Anthropometric characteristics, drying medications, clinical findings such as deformity of the nasal septum, symptoms of a chronic mucosa disease (CMD), a previous uvulopalatopharyngoplasty (UPPP), and polysomnographic parameters had no significant effect on the need for a cold humidifier. Age > 60 years (odds ratio [OR], 5.58; 95% confidence interval [CI], 1.69 to 18.43), drying medications (OR, 6.59; 95% CI, 1.29 to 33.51), presence of CMD (OR, 4.11; 95% CI, 1.24 to 13.58), and previous UPPP (OR, 4.56; 95% CI, 1.18 to 17.6) were found as significant risk factors for the addition of a heated humidifier.

CONCLUSION

Our results demonstrate that heated humidification significantly improves the nCPAP daily rate of use and that its need may be predicted.

Obstructive sleep apnea syndrome. fifty-one consecutive patients treated by maxillofacial surgery

The place of surgical treatment in obstructive sleep apnea syndrome (OSAS) remains unclear. Uvulopalatopharyngoplasty (UPPP) has a response rate of 41% overall and only 5% when retrolingual narrowing is present. Thus, in cases with suspected hypopharyngeal collapse maxillofacial surgery has been proposed with improved results. The Stanford group has designed a step-by-step surgical procedure tailored to the specific anatomical abnormalities encountered in each patient. The goal is to avoid a full maxillomandibular advancement osteotomy (MMO), at least in a subgroup of patients, beginning with a limited mandibular osteotomy (with or without hyoid myotomy and hyothyroidopexy and with or without UPPP) (phase 1 surgery). In this procedure MMO is performed as the second or third step (phase 2 surgery). The present study reports on our prospective experience with 51 consecutive patients (64 surgical procedures) treated by the step-by-step maxillofacial surgery previously described by the Stanford team. Only 2 of the 53 patients initially treated were lost for follow-up. Surgery was considered a success if the postoperative apnea and hypopnea index (AHI) was less than 15/h with at least a 50% reduction. Forty-four patients had phase 1 surgery. The success rate was 22.7% (10 of 44). The mean AHI was unchanged with a trend for reduction in the apnea index. Twenty patients had maxillomandibular advancement surgery (phase 2) (13 failures of phase 1, 7 patients primarily because of facioskeletal deformities). The AHI decreased from 59 +/- 29/h to 11 +/- 9/h after phase 2. Of the patients 75% (15 of 20) were considered to have had a successful outcome. In conclusion, phase 1 does not seem effective in most patients with OSAS. The results of phase 2 surgery are successful in young patients with severe OSAS even if the surgical technique is more aggressive.

What characterizes patients who are unable to tolerate continuous positive airway pressure (CPAP) treatment?

Continuous positive airway pressure (CPAP) is the treatment of choice for obstructive sleep apnoea syndrome (OSAS), but many patients find this treatment intolerable. The aim of this study was to characterize patients who were unable to tolerate CPAP treatment (non-complaint) as opposed to those who continued using CPAP (complaint). A case-control study was performed in which the cases comprised of 40 patients who had been started on CPAP treatment but had found the treatment unacceptable and had ceased to use CPAP. The controls comprised of 63 patients with OSAS who had been prescribed CPAP and were still using it (follow-up period 18 months to 10 yr). The patients who stopped CPAP treatment had a higher mean age, had more frequently undergone uvulopalatopharyngoplasty (UPPP) and had a lower mean oxygen desaturation index (ODI) than patients who continued using CPAP. ODI was an independent negative predictor of non-compliance (OR5units=0.6(0.4-0.8), P<0.01). The two most common reasons for non-compliance were problems in the nose or pharynx and lack of subjective effect by the treatment. High age was an independent risk factor for non-compliance because of problems in the nose or pharynx (OR10years=2.8(1.3-6.1), P<0.01), while having undergone UPPP was a risk factor for non-compliance because of lack of effect (OR=4.5 (1.1-19.1), P<0.05). In conclusion, patients with less severe OSAS are more likely to discontinue CPAP treatment. The risk of experiencing nasal and pharyngeal side-effects of such severity that the patient stops using CPAP increases with age and patients who have undergone UPPP are less likely to experience a clinical improvement after being started on CPAP therapy.

An Overview of Nasal CPAP Therapy in the Management of Obstructive Sleep Apnea

Obstructive sleep apnea is readily reversible with nasally administered continuous positive airway pressure, although its effectiveness can be limited by poor patient compliance with therapy. With recent developments in technology, the ability to both diagnose and manage this disorder is dramatically improving. Assessment and therapeutic intervention can now be carried out not only in attended settings, such as sophisticated sleep laboratories, but in semiattended and unattended situations, including the home. What impact these advances will have on improving patient tolerance to therapy and reducing long-term clinical consequences of obstructive sleep apnea remains to be seen. However, there is no doubt that sleep-trained professionals now have many more tools at their disposal to diagnose and treat this disorder.

Continuous positive airway pressure requirement during the first month of treatment in patients with severe obstructive sleep apnea

OBJECTIVES

(1) To compare the continuous positive airway pressure (CPAP) requirement at the time of diagnosis (T0), after 2 weeks (T2), and after 4 weeks (T4) of CPAP treatment, in patients with severe obstructive sleep apnea (OSA); and (2) to assess whether any alteration in CPAP requirement over the first 4 weeks of CPAP treatment would influence daytime alertness, subjective sleepiness, or mood.

DESIGN

A prospective, controlled, single-blind crossover study.

SETTING

University teaching hospital.

PATIENTS

Ten patients with newly diagnosed and previously untreated severe OSA (aged 52+/-9 years, apnea hypopnea index [AHI] of 99+/-31) and subsequently 10 control patients (aged 52+/-11 years, AHI 85+/-17).

MEASUREMENTS

Overnight polysomnography with CPAP titration to determine the CPAP requirement, which was standardized for body position and sleep stage, on all three occasions (T0, T2, T4). Objective sleep quality, daytime alertness, subjective sleepiness (Epworth Sleepiness Scale), and mood (Hospital Anxiety and Depression Scale).

RESULTS

CPAP requirement decreased from T0 to T2 (median difference, 1.5 cm H2O, 95% confidence interval [CI], 1.1 to 2.7 cm H2O, p=0.0004) and did not differ between T2 and T4. Use of the lower CPAP pressure during T2 to T4 was associated with a decrease in Epworth scale (mean difference, 2.6, 95% CI, 1.2 to 4; p=0.01) and anxiety (median change, 2; 95% CI, 0.5 to 2.9, p=0.03) scores, as compared with the first 2 weeks. Daytime alertness did not differ between T0 to T2 and T2 to T4.

CONCLUSION

CPAP requirement falls within 2 weeks of starting CPAP treatment. A change to the lower required CPAP was not associated with any deterioration in daytime alertness but was associated with small subjective improvements in sleepiness and mood.