Validation study of a portable monitoring device for identifying OSA in a symptomatic patient population

Preliminary assessment of portable sleep monitoring for diagnosis of obstructive sleep apnea in children

OBJECTIVE

By observing the differences in sleep parameters between portable sleep monitoring (PM) and polysomnography (PSG) in children, we aimed to investigate the diagnostic value and feasibility of PM in children with suspected obstructive sleep apnea (OSA).

STUDY DESIGN

This prospective study enrolled consecutive children (aged 3-14 years) with suspected OSA in Shenzhen Children's Hospital. They had PSG and PM in the sleep laboratory. Clinical parameters of the two sleep monitoring methods were compared.

RESULTS

A total of 58 children participated. They were classified into two groups according to age: 28 children aged 3 to 5 years and 30 children aged 6 to 14 years. No significant differences were observed in apnea-hypopnea index (AHI), lowest oxygen saturation (LSaO2), and mean oxygen saturation (MSaO2) between PM and PSG, but the sleep efficiency with PM was significantly higher (3-5 years age: 92.2 ± 11.3% vs 85.2 ± 14.3%, 6-14 years age: 93.2 ± 14.5% vs 84.8 ± 16.3%, both P < 0.05) than the sleep efficiency with PSG. Pearson correlation analysis indicated a strong correlation between AHI, LSaO2, MSaO2, and sleep efficiency measured by PSG and PM. Receiver operating characteristic curve (ROC) analysis showed that PM was a reliable diagnostic tool for OSA. PM has high sensitivity (3-5 years age: 95.8%, 6-14 years age: 96.3%) and low specificity (3-5 years age: 25.0%, 6-14 years age: 33.3%) for OSA in children. Thus, there is a low rate of missed diagnoses, but there is some inaccuracy in excluding children who do not have OSA.

CONCLUSION

The results showed that PM has a good correlation with the various parameters of PSG. PM may be a reliable tool for diagnosing moderate and severe OSA in children, especially those who cannot cooperate with PSG or who have limited access to PSG.

Statins Restore Endothelial Protection against Complement Activity in Obstructive Sleep Apnea: A Randomized Clinical Trial

Rationale: Increased cardiovascular risk in obstructive sleep apnea (OSA) persists after continuous positive airway pressure (CPAP) and alternative therapies are needed. Impaired endothelial protection against complement is a cholesterol-dependent process that initiates endothelial inflammation in OSA, which increases cardiovascular risk. Objectives: To investigate directly whether lowering cholesterol improves endothelial protection against complement and its proinflammatory effects in OSA. Methods: Newly diagnosed patients with OSA (n = 87) and OSA-free controls (n = 32) participated. Endothelial cells and blood were collected at baseline, after 4 weeks of CPAP therapy, and again after 4 weeks of 10 mg atorvastatin versus placebo using a randomized, double-blind, parallel-group design. Primary outcome was the proportion of a complement inhibitor, CD59, on the endothelial cell plasma membrane in OSA patients after 4 weeks of statins versus placebo. Secondary outcomes were complement deposition on endothelial cells and circulating levels of its downstream proinflammatory factor, angiopoietin-2, after statins versus placebo. Results: Baseline expression of CD59 was lower, whereas complement deposition on endothelial cells and levels of angiopoietin-2 were greater, in patients with OSA compared with controls. CPAP did not affect expression of CD59 or complement deposition on endothelial cells in patients with OSA, regardless of adherence. Compared with placebo, statins increased expression of endothelial complement protector CD59 and lowered complement deposition in patients with OSA. Good CPAP adherence was associated with increased angiopoietin-2 levels, which was reversed by statins. Conclusions: Statins restore endothelial protection against complement and reduce its downstream proinflammatory effects, suggesting a potential approach to reduce residual cardiovascular risk after CPAP in patients with OSA. Clinical trial registered with www.clinicaltrials.gov (NCT03122639).

Portable evaluation of obstructive sleep apnea in adults: A systematic review

Obstructive sleep apnea (OSA) is a significant healthcare burden affecting approximately one billion people worldwide. The prevalence of OSA is rising with the ongoing obesity epidemic, a key risk factor for its development. While in-laboratory polysomnography (PSG) is the gold standard for diagnosing OSA, it has significant drawbacks that prevent widespread use. Portable devices with different levels of monitoring are available to allow remote assessment for OSA. To better inform clinical practice and research, this comprehensive systematic review evaluated diagnostic performances, study cost and patients' experience of different levels of portable sleep studies (type 2, 3, and 4), as well as wearable devices and non-contact systems, in adults. Despite varying study designs and devices used, portable diagnostic tests are found to be sufficient for initial screening of patients at risk of OSA. Future studies are needed to evaluate cost effectiveness with the incorporation of portable diagnostic tests into the diagnostic pathway for OSA, as well as their application in patients with chronic respiratory diseases and other comorbidities that may affect test performance.

ERS technical standards for using type III devices (limited channel studies) in the diagnosis of sleep disordered breathing in adults and children

For more than three decades, type III devices have been used in the diagnosis of sleep disordered breathing in supervised as well as unsupervised settings. They have satisfactory positive and negative predictive values for detecting obstructive and central sleep apnoea in populations with moderately high pre-test probability of symptoms associated with these events. However, standardisation of commercially available type III devices has never been undertaken and the technical specifications can vary widely. None have been subjected to the same rigorous processes as most other diagnostic modalities in the medical field. Although type III devices do not include acquisition of electroencephalographic signals overnight, the minimum number of physical sensors required to allow for respiratory event scoring using standards outlined by the American Academy of Sleep Medicine remains debatable. This technical standard summarises data on type III studies published since 2007 from multiple perspectives in both adult and paediatric sleep practice. Most importantly, it aims to provide a framework for considering current type III device limitations in the diagnosis of sleep disordered breathing while raising research- and practice-related questions aimed at improving our use of these devices in the present and future.

Toward standardizing the clinical testing protocols of point-of-care devices for obstructive sleep apnea diagnosis

PURPOSE

In recent years, point-of-care (POC) devices, especially smart wearables, have been introduced to provide a cost-effective, comfortable, and accessible alternative to polysomnography (PSG)-the current gold standard-for the monitoring, screening, and diagnosis of obstructive sleep apnea (OSA). Thorough validation and human subject testing are essential steps in the translation of these device technologies to the market. However, every device development group tests their device in their own way. No standard guidelines exist for assessing the performance of these POC devices. The purpose of this paper is to critically distill the key aspects of the various protocols reported in the literature and present a protocol that unifies the best practices for testing wearable and other POC devices for OSA.

METHODS

A limited review and graphical descriptive analytics of literature-including journal articles, web sources, and clinical manuscripts by authoritative agencies in sleep medicine-are performed to glean the testing and validation methods employed for POC devices, specifically for OSA.

RESULTS

The analysis suggests that the extent of heterogeneity of the demographics, the performance metrics, subject survey, hypotheses, and statistical analyses need to be carefully considered in a systematic protocol for testing POC devices for OSA.

CONCLUSION

We provide a systematic method and list specific recommendations to extensively assess various performance criteria for human subject testing of POC devices. A rating scale of 1-3 is provided to encourage studies to put a focus on addressing the key elements of a testing protocol.

Classification of Sleep Apnea Severity by Electrocardiogram Monitoring Using a Novel Wearable Device

Sleep apnea (SA) is a prevalent disorder diagnosed by polysomnography (PSG) based on the number of apnea–hypopnea events per hour of sleep (apnea–hypopnea index, AHI). PSG is expensive and technically complex; therefore, its use is rather limited to the initial diagnostic phase and simpler devices are required for long-term follow-up. The validity of single-parameter wearable devices for the assessment of sleep apnea severity is still debated. In this context, a wearable electrocardiogram (ECG) acquisition system (ECG belt) was developed and its suitability for the classification of sleep apnea severity was investigated using heart rate variability analysis with or without data pre-filtering. Several classification algorithms were compared and support vector machine was preferred due to its simplicity and overall performance. Whole-night ECG signals from 241 patients with a suspicion of sleep apnea were recorded using both the ECG belt and patched ECG during PSG recordings. 65% of patients had an obstructive sleep apnea and the median AHI was 21 [IQR: 7–40] h−1. The classification accuracy obtained from the ECG belt (accuracy: 72%, sensitivity: 70%, specificity: 74%) was comparable to the patched ECG (accuracy: 74%, sensitivity: 88%, specificity: 61%). The highest classification accuracy was obtained for the discrimination between individuals with no or mild SA vs. moderate to severe SA. In conclusion, the ECG belt provided signals comparable to patched ECG and could be used for the assessment of sleep apnea severity, especially during follow-up.

Devices for home detection of obstructive sleep apnea: A review

One of the most common sleep-related disorders is obstructive sleep apnea, characterized by a reduction of airflow while breathing during sleep and cause significant health problems. This disorder is mainly diagnosed in sleep labs with polysomnography, involving high costs and stress for the patient. To address this situation multiple systems have been proposed to conduct the examination and analysis in the patient's home, using sensors to detect physiological signals that are examined by algorithms. The objective of this research is to review publications that show the performance of different devices for ambulatory diagnosis of sleep apnea. Commercial systems that were examined by an independent research group and validated research projects were selected. In total 117 articles were analysed, including a total of 50 commercial devices. Each article was evaluated according to diagnostic elements, level of automatisation implemented and the deducted level of evidence and quality rating. Each device was categorized using the SCOPER categorization system, including an additional proposed category, and a final comparison was performed to determine the sensors that provided the best results.

Validation of the Nox-T3 Portable Monitor for Diagnosis of Obstructive Sleep Apnea in Chinese Adults

STUDY OBJECTIVES

To evaluate the performance of a portable monitor (Nox-T3, Nox Medical Inc. Reykjavik, Iceland) used to diagnose obstructive sleep apnea in Chinese adults.

METHODS

Eighty Chinese adults (mean ± standard deviation age 47.6 ± 14.0 years, 77.5% males, body mass index 27.5 ± 5.4 kg/m²) underwent overnight, unattended home sleep apnea testing (HSAT) with the Nox-T3 portable monitor followed by an overnight in-laboratory polysomnogram (PSG) with simultaneous portable monitor recording. The portable monitor recordings were scored using automated analysis and then manually edited using different criteria for scoring hypopneas. Polysomnography was scored based on recommended guidelines.

RESULTS

When scoring of hypopneas required a ≥ 4% oxygen desaturation event, the mean ± standard deviation apnea-hypopnea index (AHI) was 24.4 ± 20.8 events/h on HSAT, 28.0 ± 22.9 events/h on in-laboratory portable monitor recording, and 28.6 ± 23.9 events/h on PSG (P < .0001). Bland-Altman analysis of AHI on PSG versus HSAT showed a mean difference (95% confidence interval) of -4.64 (-7.15, -2.13); limits of agreement (equal to ± 2 standard deviations) was -26.62 to 17.35 events/h. Based on a threshold of AHI ≥ 5 events/h, HSAT had 95% sensitivity, 69% specificity, 94% positive predictive value, and 75% negative predictive value compared to PSG. Using an AHI ≥ 15 events/h, HSAT had 93% sensitivity, 85% specificity, 89% positive predictive value, and 91% negative predictive value. Closer agreements were present when comparing the simultaneous recordings. Similar results were obtained using different scoring criteria for hypopneas.

CONCLUSIONS

Despite known differences between HSAT and PSG, the results show close agreement between the two diagnostic tests in Chinese adults, especially when controlling for night-to-night variability and changes in sleeping environment.

Computer-Assisted Diagnosis of the Sleep Apnea-Hypopnea Syndrome: A Review

Automatic diagnosis of the Sleep Apnea-Hypopnea Syndrome (SAHS) has become an important area of research due to the growing interest in the field of sleep medicine and the costs associated with its manual diagnosis. The increment and heterogeneity of the different techniques, however, make it somewhat difficult to adequately follow the recent developments. A literature review within the area of computer-assisted diagnosis of SAHS has been performed comprising the last 15 years of research in the field. Screening approaches, methods for the detection and classification of respiratory events, comprehensive diagnostic systems, and an outline of current commercial approaches are reviewed. An overview of the different methods is presented together with validation analysis and critical discussion of the current state of the art.

Validation of the Apnea Risk Evaluation System (ARES) device against laboratory polysomnography in pregnant women at risk for obstructive sleep apnea syndrome

STUDY OBJECTIVE

To assess the validity of using the Apnea Risk Evaluation System (ARES) Unicorder for detecting obstructive sleep apnea (OSA) in pregnant women.

METHODS

Sixteen pregnant women, mean age (SD) = 29.8 (5.4) years, average gestational age (SD) = 28.6 (6.3) weeks, mean body mass index (SD) = 44.7 (6.9) kg/m(2) with signs and symptoms of OSA wore the ARES Unicorder during one night of laboratory polysomnography (PSG). PSG was scored according to AASM 2007 criteria, and PSG AHI and RDI were compared to the ARES 1%, 3%, and 4% AHIs calculated with the ARES propriety software.

RESULTS

Median PSG AHI and PSG RDI were 3.1 and 10.3 events/h of sleep, respectively. Six women had a PSG AHI ≥ 5 events/h of sleep and 11 had a PSG RDI ≥ 5 events/h of sleep. PSG AHI and RDI were strongly correlated with the ARES AHI measures. When compared with polysomnographic diagnosis of OSA, the ARES 3% algorithm provided the best balance between sensitivity (1.0 for PSG AHI, 0.91 for PSG RDI) and specificity (0.5 for PSG AHI, 0.8 for PSG RDI) for detecting sleep disordered breathing in our sample.

CONCLUSIONS

The ARES Unicorder demonstrated reasonable consistency with PSG for diagnosing OSA in this small, heterogeneous sample of obese pregnant women.

Diagnostic accuracy of level 3 portable sleep tests versus level 1 polysomnography for sleep-disordered breathing: a systematic review and meta-analysis

BACKGROUND

Greater awareness of sleep-disordered breathing and rising obesity rates have fueled demand for sleep studies. Sleep testing using level 3 portable devices may expedite diagnosis and reduce the costs associated with level 1 in-laboratory polysomnography. We sought to assess the diagnostic accuracy of level 3 testing compared with level 1 testing and to identify the appropriate patient population for each test.

METHODS

We conducted a systematic review and meta-analysis of comparative studies of level 3 versus level 1 sleep tests in adults with suspected sleep-disordered breathing. We searched 3 research databases and grey literature sources for studies that reported on diagnostic accuracy parameters or disease management after diagnosis. Two reviewers screened the search results, selected potentially relevant studies and extracted data. We used a bivariate mixed-effects binary regression model to estimate summary diagnostic accuracy parameters.

RESULTS

We included 59 studies involving a total of 5026 evaluable patients (mostly patients suspected of having obstructive sleep apnea). Of these, 19 studies were included in the meta-analysis. The estimated area under the receiver operating characteristics curve was high, ranging between 0.85 and 0.99 across different levels of disease severity. Summary sensitivity ranged between 0.79 and 0.97, and summary specificity ranged between 0.60 and 0.93 across different apnea-hypopnea cut-offs. We saw no significant difference in the clinical management parameters between patients who underwent either test to receive their diagnosis.

INTERPRETATION

Level 3 portable devices showed good diagnostic performance compared with level 1 sleep tests in adult patients with a high pretest probability of moderate to severe obstructive sleep apnea and no unstable comorbidities. For patients suspected of having other types of sleep-disordered breathing or sleep disorders not related to breathing, level 1 testing remains the reference standard.

Significance of including a surrogate arousal for sleep apnea-hypopnea syndrome diagnosis by respiratory polygraphy

RATIONALE

Respiratory polygraphy is an accepted alternative to polysomnography (PSG) for sleep apnea/hypopnea syndrome (SAHS) diagnosis, although it underestimates the apnea-hypopnea index (AHI) because respiratory polygraphy cannot identify arousals.

OBJECTIVES

We performed a multicentric, randomized, blinded crossover study to determine the agreement between home respiratory polygraphy (HRP) and PSG, and between simultaneous respiratory polygraphy (respiratory polygraphy with PSG) (SimultRP) and PSG by means of 2 AHI scoring protocols with or without hyperventilation following flow reduction considered as a surrogate arousal.

METHODS

We included suspected SAHS patients from 8 hospitals. They were assigned to home and hospital protocols at random. We determined the agreement between respiratory polygraphy AHI and PSG AHI scorings using Bland and Altman plots and diagnostic agreement using receiver operating characteristic (ROC) curves. The agreement in therapeutic decisions (continuous positive airway pressure treatment or not) between HRP and PSG scorings was done with likelihood ratios and post-test probability calculations.

RESULTS

Of 366 randomized patients, 342 completed the protocol. AHI from HRP scorings (with and without surrogate arousal) had similar agreement with PSG. AHI from SimultRP with surrogate arousal scoring had better agreement with PSG than AHI from SimultRP without surrogate arousal. HRP with surrogate arousal scoring had slightly worse ROC curves than HRP without surrogate arousal, and the opposite was true for SimultRP scorings. HRP with surrogate arousal showed slightly better agreement with PSG in therapeutic decisions than for HRP without surrogate arousal.

CONCLUSION

Incorporating a surrogate arousal measure into HRP did not substantially increase its agreement with PSG when compared with the usual procedure (HRP without surrogate arousal).

Comparison of empirical continuous positive airway pressure (CPAP) treatment versus initial portable sleep monitoring followed by CPAP treatment for patients with suspected obstructive sleep apnoea

BACKGROUND

Polysomnography is labour-intensive for diagnosing obstructive sleep apnoea (OSA). We compared two algorithms for initiating continuous positive airway pressure (CPAP) treatment for patients with suspected OSA.

METHODS

Symptomatic OSA patients were randomised into either algorithm I or II. Algorithm I consisted of an empirical CPAP trial whereas algorithm II utilised an Apnea Risk Evaluation System, a wireless device applied on the forehead, for establishing a diagnosis before a CPAP trial for 3 weeks. Primary outcome was success of CPAP trial, defined as CPAP usage > 4 h/night and willingness to continue CPAP. Subjective usefulness of CPAP, accuracy of Apnea Risk Evaluation System versus polysomnography and CPAP adherence at 6 months were secondary end-points.

RESULTS

Altogether 138 patients in algorithm I and 110 patients in algorithm II completed the CPAP trial. There were no significant differences between these algorithms with respect to the primary end-point. The sensitivity and specificity of algorithm I versus II as a diagnostic test for OSA were 0.3, 0.8 versus 0.31, 1.00 respectively. In predicting CPAP adherence at 6 months, the likelihood ratio positive for algorithms I and II was 2.7 and 5.27 respectively. The mean (SE) time taken from the first consultation to the end of CPAP trial in algorithm I and algorithm II was 60 (2) and 98 (5) days, respectively, P < 0.01.

CONCLUSION

An ambulatory approach with portable sleep monitoring for diagnosing OSA before a CPAP trial can identify more patients who would adhere to CPAP at 6 months than empirical CPAP treatment alone.

Is portable monitoring accurate in the diagnosis of obstructive sleep apnea syndrome in chronic pulmonary obstructive disease?

BACKGROUND

No scientific evidence supports the use of portable devices to diagnose obstructive sleep apnea syndrome (OSAS) in patients with co-morbities. Our aim was to evaluate the accuracy of a portable monitoring device (Stardust - STD) in the detection of patients with chronic obstructive pulmonary disease (COPD).

METHODS

Patients with COPD and clinical suspicion of OSAS were recruited for a prospective randomized study. The STD was used on two different nights: (1) at home (STDHome) and (2) at the sleep laboratory simultaneous with polysomnography (PSG-STDLab).

RESULTS

A total of 72 patients underwent the proposed recordings. Forty-six volunteers were excluded due to recording problems, and data from 26 subjects were analyzed. The mean age was (mean±SD) 62.8±8.5 years, 50% were male, and the mean forced expiratory volume in the first second was 55±11%. Significant intraclass correlation was observed between apnea-hypopnea index (AHI)-PSG vs. AHI-STDLab (r=0.61, p<0.0001) and AHI-STDHome (r=0.47, p<0.007). Kappa analysis also showed a significant agreement for severe group.

CONCLUSION

Despite the agreement found in a small number of patients between AHI, a large number of failures in the recording limits the use of this portable device for the diagnosis of OSAS in patients with COPD.

Is portable monitoring for diagnosing obstructive sleep apnea syndrome suitable in elderly population?

PURPOSE

Obstructive sleep apnea syndrome (OSAS) is highly prevalent in the elderly. Unattended, at-home portable monitoring (PM) is a diagnostic alternative to polysomnography in adults with high clinical probability of OSAS. However, no studies have evaluated the diagnostic accuracy of PM in elderly population. The aim of our study was to evaluate the effectiveness of PM in elderly patients.

METHODS

We selected patients aged over 65 years with suspected OSAS. Two-order randomized evaluations were performed: one night of at-home PM (PMhome) and one night of simultaneous PM and polysomnography (PSG) in the sleep lab (PSG+PM). We obtained three different apnea-hypopnea index (AHI): AHI from PSG (AHI PSG), AHI from at-home PM (AHI PMhome), and AHI from PM+PSG (AHI PM+PSG). Two technicians, blinded to the recording order, scored each sleep study.

RESULTS

We studied a total of 43 patients. No difference between the AHI values for each of the different recordings was found (p > 0.05). There was good correlation between AHI PSG and AHI PMhome (r = 0.67) and AHI PSG+PM (r = 0.84). The area under the receiver operator curve was above 0.83, indicating good sensitivity and a positive predictive value for AHI with cutoffs of 5, 15, and 30 and good specificity and negative predictive value for AHI values above 15. Correlation, accuracy, and agreement were greater when the recordings were made simultaneously.

CONCLUSIONS

PM was effective for diagnosing OSAS in the elderly and can be used as an alternative to PSG in elderly patients with a high clinical probability of OSAS.

Obstructive sleep apnea devices for out-of-center (OOC) testing: technology evaluation

Guidance is needed to help clinicians decide which out-of-center (OOC) testing devices are appropriate for diagnosing obstructive sleep apnea (OSA). A new classification system that details the type of signals measured by these devices is presented. This proposed system categorizes OOC devices based on measurements of Sleep, Cardiovascular, Oximetry, Position, Effort, and Respiratory (SCOPER) parameters.Criteria for evaluating the devices are also presented, which were generated from chosen pre-test and post-test probabilities. These criteria state that in patients with a high pretest probability of having OSA, the OOC testing device has a positive likelihood ratio (LR+) of 5 or greater coinciding with an in-lab-polysomnography (PSG)-generated apnea hypopnea index (AHI) ≥ 5, and an adequate sensitivity (at least 0.825).Since oximetry is a mandatory signal for scoring AHI using PSG, devices that do not incorporate oximetry were excluded. English peer-reviewed literature on FDA-approved devices utilizing more than 1 signal was reviewed according to the above criteria for 6 questions. These questions specifically addressed the adequacy of different respiratory and effort sensors and combinations thereof to diagnose OSA. In summary, the literature is currently inadequate to state with confidence that a thermistor alone without any effort sensor is adequate to diagnose OSA; if a thermal sensing device is used as the only measure of respiration, 2 effort belts are required as part of the montage and piezoelectric belts are acceptable in this context; nasal pressure can be an adequate measurement of respiration with no effort measure with the caveat that this may be device specific; nasal pressure may be used in combination with either 2 piezoelectric or respiratory inductance plethysmographic (RIP) belts (but not 1 piezoelectric belt); and there is insufficient evidence to state that both nasal pressure and thermistor are required to adequately diagnose OSA. With respect to alternative devices for diagnosing OSA, the data indicate that peripheral arterial tonometry (PAT) devices are adequate for the proposed use; the device based on cardiac signals shows promise, but more study is required as it has not been tested in the home setting; for the device based on end-tidal CO(2) (ETCO(2)), it appears to be adequate for a hospital population; and for devices utilizing acoustic signals, the data are insufficient to determine whether the use of acoustic signals with other signals as a substitute for airflow is adequate to diagnose OSA.Standardized research is needed on OOC devices that report LR+ at the appropriate AHI (≥ 5) and scored according to the recommended definitions, while using appropriate research reporting and methodology to minimize bias.

Initial Evaluation of a Titration Appliance for Temporary Treatment of Obstructive Sleep Apnea

Background

Custom oral appliances that adjustably advance the mandible provide superior outcomes when treating patients with moderate or severe sleep apnea. Custom appliances, however, are expensive, must be fitted by a dentist, and the likelihood of successful outcomes are difficult to predict. An inexpensive trial appliance, if proven efficacious, might be used to predict custom appliance outcomes or to provide temporary therapeutic benefit.

Objective

The aim of this initial study was to assess the treatment efficacy of a novel titration oral appliance with that of an optimized custom appliance.

Methods

Seventeen patients, treated with a custom oral appliance for at least one year, successfully completed a three-night home sleep test. The baseline obstructive sleep apnea severity was established on Night 1 with seven patients exhibiting severe, six moderate and four mild apnea/hypopnea indexes. Patients were randomly assigned to wear their custom appliance or the titration appliance on Nights 2 and 3.

Results

Significant reductions in the mean overall and supine apnea indexes (p < 0.05), and the overall (p < 0.01) and supine (p < 0.05) apnea/hypopnea indexes were observed for both the titration and custom appliances. The proportion of patients who exhibited at least a 50% reduction in the overall apnea index and supine apnea/hypopnea were similar for the titration and custom appliance (~60%). The custom appliance reduced the overall apnea/hypopnea index by 50% in a greater proportion of the patients compared to the titration appliance (77% vs. 53%). The titration appliance significantly reduced the degree of hypoxic exposure across sleep disordered breathing events overall (p < 0.05) and supine (p < 0.01). Patients found their custom appliance was more comfortable than the titration appliance, but preferred the titration appliance to no therapy.

Conclusion

The titration appliance may be useful in assessing oral appliance treatment efficacy. When set to 70% of maximum protrusion, the titration appliance may provide immediate, temporary therapeutic benefit.

Validation of the MediByte® type 3 portable monitor compared with polysomnography for screening of obstructive sleep apnea

BACKGROUND

Portable monitors are increasingly being used as a diagnostic screening tool for obstructive sleep apnea (OSA), and in-laboratory validation of these devices with polysomnography (PSG) is required.

OBJECTIVE

To assess the reliability of the MediByte (Braebon Medical Corporation, Canada) type 3 screening device compared with overnight PSG.

METHODS

To cover a range of OSA severity, a consecutive series of patients wore the screening device while simultaneously undergoing PSG. Data acquired from the screener and PSG were blinded and scored separately. The number of apneas and hypopneas per hour were calculated using recording time (respiratory disturbance index [RDI]) for the MediByte device, and sleep time (apnea-hypopnea index [AHI]) for PSG.

RESULTS

Data from 73 patients with a mean age of 53 years and body mass index of 32.2 kg⁄m2 showed high measurement association between the RDI and AHI, with a Pearson correlation of 0.92, accounting for 85% of the variance. Based on Bland-Altman measurement agreement, the mean difference between the RDI and AHI (-5.9±11.2 events⁄h) indicated screener under-reporting. For an AHI of greater than 15 events⁄h, the sensitivity and specificity of the screener was 80% and 97%, respectively; for an AHI of greater than 30 events⁄h, the positive predictive value was 100%, while the negative predictive value was 88%.

CONCLUSION

The MediByte device accurately identified patients without OSA and had a high sensitivity for moderate-to-severe OSA.

Validation of Embletta portable diagnostic system for identifying patients with suspected obstructive sleep apnoea syndrome (OSAS)

The Embletta portable diagnostic system is highly sensitive and specific in quantifying the AHI and differentiating obstructive and supine events when compared against hospital-based PSG in patients with suspected OSAS. The simple device may be useful for screening and diagnostic purpose when access to PSG is limited.

BACKGROUND AND OBJECTIVES

This study aimed to evaluate the diagnostic accuracy of Embletta portable diagnostic system (PDS, Medcare, Reykjavik, Iceland) for the screening of sleep apnoea in clinical practice.

METHODS

The Embletta PDS is a digital three-channel recording device that measures airflow through a nasal cannula connected to a pressure transducer, oxygen saturation plus both respiratory and abdominal movements via built-in effort and body position sensors. An AHI is determined based on recording time. Nocturnal polysomnography (Alice 4, Healthdyne, Atlanta, USA), with airflow measured by a nasal pressure transducer (PTAF2, Pro-Tech, Woodinville, WA, USA)) and Embletta PDS recordings, was performed simultaneously in consecutive patients with suspected OSA syndrome. The PSG recordings were analysed manually by a blinded investigator.

RESULTS

Ninety subjects were recruited and 10 failed Embletta PDS studies due to measurement failure. Among the remaining 80 subjects, 63 were males. The mean age (SD) was 51.4 (11.9) years old, BMI 27.1(4.2) kg/m2, neck circumference 38.6 (3.6) cm and Epworth Sleepiness Score 9.7 (5.3). The AHI obtained by the Embletta PDS correlated closely with that obtained by PSG (Pearson correlation, r=0.979, P<0.001). Comparison of AHI based on the Embletta PDS against the PSG demonstrated high sensitivity at AHI>or=5/h (sensitivity 0.924 and specificity 0.857) and high specificity at AHI>or=20/h (sensitivity 0.853 and specificity 0.957).

CONCLUSIONS

The Embletta PDS is a highly sensitive and specific screening device in quantifying AHI when compared against PSG in patients with suspected OSA syndrome.