Residual sleep apnea on polysomnography after 3 months of CPAP therapy: Clinical implications, predictors and patterns

doi:10.1016/j.sleep.2009.05.017

Sleep Medicine

Volume 11, Issue 2, February 2010, Pages 119-125

https://doi.org/10.1016/j.sleep.2009.05.017 Get rights and content

Abstract

Objective

We sought to determine the clinical implications, predictors and patterns of residual sleep apnea on continuous positive airway pressure (CPAP) treatment in patients with moderate-to-severe obstructive sleep apnea (OSA).

Methods

We performed a post hoc secondary analysis of data from a previously reported randomized trial. Sleepy patients with a high risk of moderate-to-severe OSA identified by a diagnostic algorithm were randomly assigned to standard CPAP titration during polysomnography (PSG) or ambulatory titration using auto-CPAP and home sleep testing. We observed them for 3 months and measured apnea–hypopnea index (AHI) on CPAP, Epworth sleepiness scale (ESS), sleep apnea quality of life index (SAQLI), CPAP pressure and objective CPAP compliance.

Results

Sixty-one patients were randomized, 30 to the PSG group and 31 to the ambulatory group. Fifteen patients (25%) had residual sleep apnea (AHI >10/h on CPAP) with similar proportions in the PSG (7/30) and ambulatory (8/31) groups. Baseline variables including age, body mass index (BMI), ESS, SAQLI, respiratory disturbance index (RDI) and CPAP pressure did not differ between the groups. Outcomes including compliance were worse in patients with residual sleep apnea. Periodic breathing was prevalent among patients with residual sleep apnea.

Conclusions

Residual sleep apnea is common in patients with moderate-to-severe OSA, despite careful CPAP titration, and is associated with worse outcomes.

Introduction

Continuous positive airway pressure (CPAP) is the treatment of choice for OSA and is highly effective. In a previously reported study of ambulatory versus in-laboratory CPAP titration in patients with moderate-to-severe obstructive sleep apnea (OSA) [1], we noted a relatively high proportion of patients with residual sleep apnea as defined by an apnea–hypopnea index (AHI) of >10/h on CPAP. Given the limited access to PSG and the increasing demands on sleep services [2], it is unusual in routine clinical practice to repeat a PSG after initial CPAP titration for the purpose of determining ongoing CPAP efficacy. Several recent studies have documented residual sleep apnea in CPAP-treated patients, and the term complex sleep apnea has been used by some to describe this phenomenon [3], [4], [5], [6], [7]. The consequences of residual sleep apnea are unknown but could be significant since patients with even mild OSA may be at increased risk of cardiovascular complications and motor vehicle crashes [8], [9], [10]. Also, suboptimal CPAP treatment may be ineffective in lowering blood pressure [11]. It is therefore important to understand the clinical implications, potential predictors and patterns of residual sleep apnea on CPAP treatment.

Section snippets

Methods

We previously conducted a randomized, controlled trial to compare standard PSG versus ambulatory CPAP titration in high-risk sleepy patients with OSA identified by a diagnostic algorithm. The details of that trial have been published elsewhere [1]. Briefly, patients referred to our sleep clinic for assessment of suspected sleep-disordered breathing were screened for potential inclusion in the study. High risk patients for moderate-to-severe OSA were identified by a diagnostic algorithm and

Residual sleep apnea

Of 81 who were eligible at clinical assessment, 68 were randomly assigned, and 61 completed the 3-month trial. The median (interquartile range) residual AHI was 2.9 (1 to 3 – 9.3)/h for the whole group of 61 patients. The most frequently observed residual respiratory events were classified as obstructive hypopneas and were present in all patients, accounting for 66% of all events. Central apneas were the next most prevalent, occurring in 86% of patients but accounting for only 10% of events. A

Discussion

Our results show that, despite rigorous CPAP titration and apparent clinical improvement in the group as a whole, residual sleep apnea on CPAP is relatively common on follow-up PSG in patients with moderate-to-severe OSA. Baseline characteristics are unhelpful in predicting residual sleep apnea. Patients with residual sleep apnea have worse outcomes. The combination of downloaded data from the CPAP machine indicating a residual AHI >10/h, together with residual sleepiness as evidenced by an ESS

Acknowledgements

This research was supported by a Grant-in-Aid from ResMed Corp., Poway, California, and VitalAire Canada, Inc., Mississauga, Ontario, Canada; and a Michael Smith Foundation for Health Research Infrastructure Grant (Sleep-Disordered Breathing). Dr. Mulgrew was supported by a BC Lung Fellowship and by a CIHR/HSFC IMPACT training program. Dr. Ayas is supported by a Michael Smith Foundation for Health Research Scholar Award, a CIHR/BC Lung Association New Investigator Award, and a Departmental

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Reliability of automatic detection of AHI during positive airway pressure treatment in obstructive sleep apnea patients: A “real-life study”
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Citation Excerpt :
Previous studies reported a high percentage of patients, already on PAP treatment, who showed persistent respiratory events despite absence of symptoms or major side effects (large mask leak, congestion, reduced tolerance). We found a lower rate (18.7%) of persistent OSA (obstructive AHI >5) [19–21] that was not associated with residual ESS or residual symptoms. Altogether, these data suggest to reconsider previous AASM or ATS recommendations [2,16].
Automatic event detection (AED) of residual apnea-hypopnea index (AHI) by ventilators is a current practice in sleep and mechanical ventilation Units but this methodology has not been validated in an unselected population of OSA patients. Aim of the present study was to assess in a “real-life” condition the reliability of AED during PAP therapy by the in-built software compared to full polysomnography during follow-up.
We enrolled 300 OSA patients (105 F; AHI 45.3 ± 27.8) already on Positive airway pressure (PAP) therapy: 53% of the patients were on CPAP while other modalities were used in the rest of the sample.
Overall, the built-in software identified residual obstructive AHI (AHI_PAP) > 5, 10 or 15 in 18.7, 8.6 or 4.6% of patients, respectively. By using AHI_PAP, 28.4% of patients were wrongly classified as “well controlled” despite a residual AHI_PSG>5 (6% considering a residual AHI_VENT >15); 7% of patients were classified as not controlled while AHI_PSG was <5 (1.4% considering a residual AHI_VENT >15). Type of ventilation, ventilator parameters, adherence to treatment and level of baseline or follow-up Epworth Sleepiness Scale score were similar between groups. The sensitivity and positive predicted values were very low. Positive likelihood ratio appears adequate only for residual AHI_PAP ≥10, but negative likelihood ratio was inconclusive for all the cut-off considered.
The results of the present study suggest a more cautious approach in the follow-up of OSA patients, since a protocol based only on AED detection and symptoms assessment may not be accurate especially for AHI_PAP<15.
Trajectories of Emergent Central Sleep Apnea During CPAP Therapy
2017, Chest
The emergence of central sleep apnea (CSA) during positive airway pressure (PAP) therapy has been observed clinically in approximately 10% of obstructive sleep apnea titration studies. This study assessed a PAP database to investigate trajectories of treatment-emergent CSA during continuous PAP (CPAP) therapy.
U.S. telemonitoring device data were analyzed for the presence/absence of emergent CSA at baseline (week 1) and week 13. Defined groups were as follows: obstructive sleep apnea (average central apnea index [CAI] < 5/h in week 1, < 5/h in week 13); transient CSA (CAI ≥ 5/h in week 1, < 5/h in week 13); persistent CSA (CAI ≥ 5/h in week 1, ≥ 5/h in week 13); emergent CSA (CAI < 5/h in week 1, ≥ 5/h in week 13).
Patients (133,006) used CPAP for ≥ 90 days and had ≥ 1 day with use of ≥ 1 h in week 1 and week 13. The proportion of patients with CSA in week 1 or week 13 was 3.5%; of these, CSA was transient, persistent, or emergent in 55.1%, 25.2%, and 19.7%, respectively. Patients with vs without treatment-emergent CSA were older, had higher residual apnea-hypopnea index and CAI at week 13, and more leaks (all P < .001). Patients with any treatment-emergent CSA were at higher risk of therapy termination vs those who did not develop CSA (all P < .001).
Our study identified a variety of CSA trajectories during CPAP therapy, identifying several different clinical phenotypes. Identification of treatment-emergent CSA by telemonitoring could facilitate early intervention to reduce the risk of therapy discontinuation and shift to more efficient ventilator modalities.
Sleep-Disordered Breathing and Excessive Daytime Sleepiness
2017, Sleep Medicine Clinics
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A study of 61 patients titrated on CPAP using conventional methods found that 25% of patients had residual sleep apnea (AHI >10) while using CPAP, and these patients tended to have higher ESS scores. Periodic breathing was often present in this subset.124 The role of adherence is highlighted by Gasa and colleagues,121 who found reduction of residual sleepiness from 18.5% to 8.7% comparing patients using CPAP ≤4 to greater than 6 hours per night, respectively.
Adaptive Servoventilation Device Software in the Assessment of Residual Respiratory Events in Patients With Central or Complex Apnoeas
2017, Archivos de Bronconeumologia
Pharmacotherapy for residual excessive sleepiness and cognition in CPAP-treated patients with obstructive sleep apnea syndrome: A systematic review and meta-analysis
2016, Sleep Medicine Reviews
Pharmacotherapy has been used as an adjunct to CPAP for treatment of residual excessive sleepiness in patients with a diagnosis of obstructive sleep apnea syndrome (OSAS). However, no studies with a high level of evidence have been conducted to support this practice and confirm its effectiveness. We conducted a meta-analysis to summarize and quantify the effects of pharmacological treatment in adults with OSAS who experience residual excessive sleepiness despite adequate CPAP use. We reviewed clinical trials that compared medications to placebo and evaluated the outcomes residual excessive sleepiness, cognition, and quality of life, as well as treatment effectiveness and safety. The MEDLINE, EMBASE, LILACS, Cochrane Central Register of Controlled Trials – CENTRAL, and PsycINFO electronic databases were searched using highly sensitive search strategies. Trials were only included if measures were taken to ensure effective CPAP treatment. Eight randomized clinical trials were included. Pharmacotherapy with modafinil and armodafinil led to improvement of excessive daytime sleepiness, attention/alertness, and clinical condition as measured with the CGI-C. No improvements in quality of life or other cognitive domains (including memory, executive function, and language) could be confirmed. Pharmacotherapy did not cause any severe adverse effects, but was associated with significant dropout rates as compared with placebo. In conclusion, although our results demonstrate the effectiveness of pharmacological treatment as an adjunct to CPAP, further investigation is necessary to improve confidence in its effects. Many findings on the impact of pharmacotherapy on cognition and quality of life were evaluated through analysis of single studies, with heterogeneity in tests and absence of standardization, which reduced certainty as to whether actual improvement occurred in these outcomes.
Polygraphic respiratory events during sleep in children treated with home continuous positive airway pressure: Description and clinical consequences
2015, Sleep Medicine
Citation Excerpt :
However, once CPAP is successfully instituted, validated follow-up guidelines are lacking. Current guidelines recommend a periodic reassessment of CPAP pressure [9]; a large adult series has shown the need for an active re-evaluation of pressure therapy, even after accurate titration studies [10,11]. This may be even more relevant for children whose condition may improve with age due to a physiological increase in upper airway caliber and patency, or worsen because of weight gain or upper respiratory infections or allergy.
Data are scarce on respiratory events during sleep for children treated at home with continuous positive airway pressure (CPAP). The present study aimed to characterize the respiratory events with CPAP during sleep and to analyze their clinical consequences.
Consecutive polygraphies (PG) performed on stable children treated with CPAP were analyzed and scored using SomnoNIV Group definitions. For every respiratory event, the presence of a 3% oxygen desaturation and/or an autonomic arousal was systematically searched. Nocturnal gas exchange was assessed using summary data of oximetry and transcutaneous carbon dioxide pressure recordings.
Twenty-nine consecutive polygraphies, performed on 26 children (mean age 7.8 ± 6.2 years, mean CPAP use 10.6 ± 14.4 months), were analyzed. The index of total respiratory events was low (median value 1.4/h, range 0–34). The mean number of different types of respiratory events per PG was 2 ± 1 (range 0–4), with always a predominant event. Partial or total upper airway obstruction without a decrease in ventilatory drive was the most frequent event and was the most frequently associated with an oxygen desaturation (in 30% of the events) and an autonomic arousal (in 55% of the events). Weak correlations were observed between nocturnal oximetry and PG results.
The index of respiratory events during CPAP treatment for stable children is low. As these events may be associated with an oxygen desaturation or an autonomic arousal, and as nocturnal gas exchange cannot predict PG results, a systematic sleep study seems justified for the routine follow-up of children treated with CPAP.

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Original ArticleResidual sleep apnea on polysomnography after 3 months of CPAP therapy: Clinical implications, predictors and patterns

Abstract

Objective

Methods

Results

Conclusions

Introduction

Section snippets

Methods

Residual sleep apnea

Discussion

Acknowledgements

Lancet

Chest

Diagnosis and initial management of obstructive sleep apnea without polysomnography: a randomized validation study

Ann Int Med

Access to diagnosis and treatment of patients with suspected sleep apnea

Am J Respir Crit Care Med

Complex sleep apnea syndrome: is it a unique clinical syndrome?

Sleep

Follow-up assessment of CPAP efficacy in patients with obstructive sleep apnea using an ambulatory device based on peripheral arterial tonometry

Sleep Breath

Central sleep apnea on commencement of continuous positive airway pressure in patients with a primary diagnosis of obstructive sleep apnea–hypopnea

J Clin Sleep Med

Complex sleep apnea: it really is a disease

J Clin Sleep Med

Prevalence of persistent sleep apnea in patients treated with continuous positive airway pressure

Sleep

Sleep-disordered breathing and cardiovascular disease: cross-sectional results of the Sleep Heart Health Study

Am J Respir Crit Care Med

Sleep-disordered breathing and motor vehicle accidents in a population-based sample of employed adults

Sleep

Population-based study of sleep-disordered breathing as a risk factor for hypertension

Arch Int Med

Polysomnography task force, American sleep disorders association standards of practice committee

Sleep

Canadian thoracic society guidelines: diagnosis and treatment of sleep disordered breathing in adults

Can Respir J

Original Article
Residual sleep apnea on polysomnography after 3 months of CPAP therapy: Clinical implications, predictors and patterns