The feasibility of using mouthpiece ventilation in the intensive care unit for post-extubation breathing support after acute tetraplegia.

STUDY DESIGN: A prospective cohort of patients with acute tetraplegia. OBJECTIVES: This study aimed to determine the feasibility of using mouthpiece ventilation (MPV) in the intensive care unit (ICU) for patients who are extubated after suffering an acute cervical spinal cord injury (CSCI). SETTING: ICU, Princess Alexandra Hospital, Brisbane Australia. METHODS: New admissions to ICU in the 14 months between April 2017 and June 2018 with a CSCI who underwent intubation were assessed for inclusion. MPV was provided to consenting participants (who were deemed likely to be able to maintain ventilation on their own) at the time of extubation and was utilised in addition to standard care while participants were awake. MPV settings, usage, and support hours to educate and facilitate MPV were collected. Feedback from participants and clinical staff was gathered throughout the study. Pre- and post-extubation measures of forced vital capacity (FVC), the frequency of endotracheal suction of sputum, and gas exchange using ventilation-perfusion ratios were recorded along with the incidence of reintubation. RESULTS: Fourteen participated in utilising MPV with 16 episodes of extubation. The average time per participant to have MPV titrated and bedside data collected was 178 minutes. Data from 16 episodes of extubation have been included. Three of the 14 participants failed initial extubation. Feedback from participants and clinicians has been positive and constructive, enabling MPV settings to be adapted to the person with acute CSCI during this pilot study. CONCLUSION: MPV is feasible to use post-extubation for people with CSCI in ICU. Pressure control mode MPV was deemed the most suitable for newly extubated acute CSCI patients. Intensive clinical support is required initially to provide education prior to MPV, and at the time of extubation for both patient and treating clinicians. Both report it to be a useful adjunct to ICU treatment.

Polysomnographic risk factors for vigilance-related cognitive decline and obstructive sleep apnea.

PURPOSE: Cognitive decline (CD) and obstructive sleep apnea (OSA) are often comorbid. Some modifiable risk factors (RF) for CD are also associated with OSA. Diagnostic polysomnography (PSG) measures these RF and may identify at risk patients prior to the onset of CD. We aim to determine whether there are severe RF associated with established CD and an increasing severity of OSA that could identify patients at risk for CD for medical intervention. METHODS: We gathered information from subjects having type 1 PSG for suspected OSA. The psychomotor vigilance task (PVT) measured established CD (group 0 and group1). We compared levels of severe RF in group 0 and group 1 with a larger group (group 2) without the PVT. We used severe standardized values of excessive daytime sleepiness (Epworth Sleepiness Score [ESS]), overnight change of systolic blood pressure (ΔSBP), change of oxygen desaturation (ΔSpO2), and sleep arousal (ArI) as RF. We compared the severe levels of ESS, ΔSBP, ΔSpO2, and ArI by group and OSA severity. RESULTS: A total of 136 patients underwent diagnostic PSG. PVT parameters were available for 43 subjects. The severity of the RF was consistent with risk for CD (ΔSBP 22.0 ± 5.6, ESS 18.2 ± 2.2, ArI 58.8 ± 18.7, ΔSpO2 61.7 ± 21.9). The levels of RF increased with increasing severity of OSA. There were significant between-group differences for severe ΔSpO2 (p = 0.004) and ΔSpO2 + ArI (p = 0.019). CONCLUSION: The levels of RF increase with increasing OSA severity. Subjects with severe RF ΔSpO2 and ΔSpO2 + ArI are likely to have PVT-determined CD. Risk factor analysis may screen for CD.

Longer duration electroencephalogram arousals have a better relationship with impaired vigilance and health status in obstructive sleep apnoea.

PURPOSE: Obstructive sleep apnoea (OSA) is a prevalent sleep disorder with significant health consequences. Sleep fragmentation is a feature of OSA and is often determined by the arousal index (ArI), a metric based on the electroencephalograph (EEG). The ArI has a weak correlation with neurocognitive outcomes in OSA patients. In this study, we examine whether changing from the current minimum EEG arousal duration of 3 s improves the association between sleep fragmentation and neurocognitive outcomes. METHODS: In a retrospective study, we selected OSA patients without any other comorbidities that are associated with neurocognitive impairment. The OSA patients were clustered into two groups based on their psychomotor vigilance task (PVT) performance to represent impaired and unimpaired neurocognition. RESULTS: While no differences were found in demographics or usual sleep study statistics, the impaired group had a greater number of EEG arousals greater than 5 s (P = 0.034), 7 s (P = 0.041), and 15 s (P = 0.036) in duration. There were no differences in the number of EEG arousals associated with sleep-disordered breathing events. These differences also corresponded with quality of life outcomes between the two groups. An ArI with a duration of 5 s or greater had the best combination of sensitivity (70.0%) and specificity (66.7%) compared with the usual 3 s duration (sensitivity and specificity of 70.0% and 53.3%, respectively). CONCLUSION: A re-examination of the EEG arousal scoring rules, and their duration, may help with allocation of health resources to OSA patients most in need.

A randomised crossover trial comparing nasal masks with oronasal masks: No differences in therapeutic pressures or residual apnea-hypopnea indices.

In treating obstructive sleep apnea (OSA), the use of oronasal masks with continuous positive airway pressure (CPAP) has been reported to increase pressure levels and reduce compliance. These reports come mostly from large observational studies. In this study, we examined the impact that oronasal masks have on 95th centile pressures, the residual apnea-hypopnea index (AHI) and compliance compared with nasal masks. A randomised crossover design was implemented. Participants already established on CPAP were randomly allocated to a nasal mask or oronasal mask with auto-titrating positive airway pressure (APAP) for 2 weeks. Participants then crossed over to use the alternate mask for another 2 weeks. Seventy-one participants were recruited but only 60 completed the trial. There were no differences in median 95th centile pressure (nasal, 11.5 cm H2 O; oronasal, 11.7 cm H2 O; p = 0.115), median residual AHI (nasal, 4.9 events/hr; oronasal, 5.3 events/hr; p = 0.234) or median compliance (nasal, 7.3 hr/night; oronasal, 7.3 hr/night; p = 0.961). Only four patients had 95th centile pressures that were at least 1.5 cm H2 O greater with oronasal masks. Oronasal masks do not systematically increase therapeutic CPAP requirements. Rather, a small subset of patients display significant differences in CPAP levels.

The prevalence of REM-related obstructive sleep apnoea is reduced by the AASM 2012 hypopnoea criteria.

PURPOSE: The variations in reported prevalence of rapid eye movement-related obstructive sleep apnoea (REM-OSA) have been attributed to different definitions, although the effect of hypopnoea criteria has not been previously investigated. METHODS: Within this retrospective study, 134 of 382 consecutive patients undertaking polysomnography (PSG) for the suspicion of OSA met the inclusion criteria. PSGs were scored using both the 2007 AASM recommended hypopnoea criteria (AASM2007Rec) and the 2012 AASM recommended hypopnoea criteria (AASM2012Rec). For each hypopnoea criteria, REM-OSA patients were grouped as REM-related [either as REM-predominant OSA (rpOSA) or REM-isolated OSA (riOSA)] or non-stage-specific OSA (nssOSA). Outcome measures (SF-36, FOSQ and DASS-21) were also compared between groups. RESULTS: Incorporation of the AASM2012Rec criteria compared to the AASM2007Rec criteria increased the apnoea-hypopnoea index (AHI) for NREM and REM sleep but decreased the AHIREM/AHINREM ratio from 1.9 to 1.3 (p < 0.001). It also decreased the prevalence of riOSA [15.7 vs 2.2% (p < 0.001) for AASM2007Rec and AASM2012Rec, respectively]. The prevalence of rpOSA remained the same for each hypopnoea criteria although the prevalence of nssOSA increased with the AASM2012Rec hypopnoea criteria [53.0 vs 66.4% (p < 0.006) for AASM2007Rec and AASM2012Rec, respectively]. There were no differences in clinical symptoms between the groups, irrespective of hypopnoea criteria used. CONCLUSIONS: This study demonstrates that in comparison with AASM2007Rec, the AASM2012Rec hypopnoea criteria reduce the prevalence of riOSA but not rpOSA by reducing the ratio of REM respiratory events and NREM respiratory events.

Management of hypoxaemic respiratory failure in a Respiratory High-dependency Unit.

BACKGROUND: There are limited data on outcomes of hypoxaemic respiratory failure (HRF), especially in non-intensive care unit (ICU) settings. AIM: To assess outcomes in HRF (without multi-system disease and not requiring early intubation) of patients directly admitted to a Respiratory High-dependency Unit (R-HDU). METHODS: This is a retrospective cohort study of HRF compared to hypercapnic respiratory failure (HCRF) in a R-HDU (2007-2011). Patient characteristics (age, gender, pre-morbid status, diagnoses) and outcomes (non-invasive ventilation (NIV) use, survival, ICU admission) were assessed. RESULTS: There were 1207 R-HDU admissions in 2007-2011, 205 (17%) with HRF and 495 (41%) with HCRF. The proportion with HRF increased from 12.2% in 2007 to 20.1% in 2011 (P < 0.05). HRF patients were younger, more often male and had better pre-morbid performance. Compared to HCRF, HRF was more frequently associated with lung consolidation (61% vs 15%, P < 0.001), interstitial lung disease (12% vs 1%, P < 0.001) and pulmonary hypertension (7% vs 0%, P < 0.001) and less frequently with chronic obstructive pulmonary disease (24% vs 65%, P < 0.001) and obstructive sleep apnoea (8% vs 26%, P < 0.001). Fewer patients with HRF were treated with NIV (28% vs 87%, P < 0.001), but NIV was discontinued early more often (28% vs 7%, P < 0.001). A total of 18% with HRF was transferred to ICU compared to 6% with HCRF (P = 0.06). More patients with HRF died (19.5% vs 12.3%, P = 0.02). Interstitial lung disease, consolidation, shock, malignancy and poorer pre-morbid function were associated with increased mortality. CONCLUSION: Initial R-HDU management is an effective option in selected HRF to reduce ICU demand, although mortality and clinical deterioration despite NIV are more common than in HCRF.

Amsterdam positional OSA classification: the AASM 2012 recommended hypopnoea criteria increases the number of positional therapy candidates.

PURPOSE: This study examined the effect of hypopnoea criteria on the prevalence of positional obstructive sleep apnoea (pOSA) identified under the Amsterdam Positional OSA Classification (APOC) system. METHODS: Three hundred three consecutive patients undertaking polysomnography (PSG) for the suspicion of OSA were included in this retrospective investigation. PSGs were scored using both the 2007 American Academy of Sleep Medicine (AASM) recommended hypopnoea criteria (AASM2007Rec) and the 2012 AASM recommended hypopnoea criteria (AASM2012Rec). For each hypopnoea criteria, OSA patients were grouped according to the APOC categories (I, II or II) or else deemed non-APOC if they did not meet the APOC criteria. Outcome measures, such as Functional Outcomes of Sleep Questionnaire (FOSQ), MOS 36-item short-form health survey (SF-36) and psychomotor vigilance task (PVT), were also compared between the groups. RESULTS: The AASM2012Rec increased the prevalence of OSA compared to AASM2007Rec. The AASM2012Rec trebled the number of APOC I patients compared to AASM2007Rec (297% increase) as well as increased the proportion of females in the APOC I group. AASM2012Rec did not change the number of APOC II and APOC III patients. In fact, the same patients were present in these categories irrespective of hypopnoea criteria. The proportion of non-APOC patients proportionally decreased with the AASM2012Rec criteria. There were no differences in outcome measures between the AASM2012Rec and AASM2007Rec groups. CONCLUSIONS: This study demonstrates that, compared to AASM2007Rec, AASM2012Rec increases the prevalence of who could be successfully treated with positional therapy. The proportion of females with pOSA also increases as a consequence of AASM2012Rec.

Severity of desaturation events differs between hypopnea and obstructive apnea events and is modulated by their duration in obstructive sleep apnea.

PURPOSE: Frequency of apnea and hypopnea events is used to estimate the severity of obstructive sleep apnea (OSA). However, comprehensive information on whether apneas and hypopneas cause an equal biological effect is not available. The purpose of the present work was to evaluate the effect of the breathing cessation event type (i.e., obstructive apnea or hypopnea) and duration on the severity of related SpO2 desaturation events. METHODS: Type 1 polysomnographies of 395 patients (220 males and 175 females) examined for suspected OSA were analyzed. Desaturation severity related to hypopnea and obstructive apnea events were compared and comparison was controlled for gender, sleep stage, sleeping position, age, and body mass index. Hypopneas and obstructive apneas were further divided into eight different durational categories and related desaturation event characteristics were compared between the categories. RESULTS: SpO2 desaturation events caused by obstructive apneas were statistically significantly (p ≤ 0.004) longer, greater in area, and deeper compared to the SpO2 desaturations caused by hypopneas. The increase in the duration of hypopnea and obstructive apnea events led to increase in the duration and area of related SpO2 desaturations. The increase in the obstructive apnea event duration also led to increase in the depth of related desaturation event. CONCLUSIONS: Obstructive apneas led to more severe SpO2 desaturation compared to hypopneas. Increased event duration led to increase in the severity of the related SpO2 desaturation. In addition to considering event duration, obstructive apneas should have more weight than hypopneas when estimating severity of OSA and associated long-term cardiovascular risk.

Nutritional Support in Malnourished Outpatients with Chronic Obstructive Pulmonary Disease (COPD): A Randomized Controlled Pilot Study.

(1) Background: The evidence for nutritional support in COPD is almost entirely based on ready-to-drink oral nutritional supplements (ONSs). This study aimed to explore the effectiveness of powdered ONSs alongside individualized dietary counseling in the management of malnutrition. (2) Methods: Malnourished outpatients with COPD were randomized to receive either routine care (Group A: counseling + recommended to purchase powdered ONSs) or an enhanced intervention (Group B: counseling + provision of powdered ONSs at no cost to the patient) for 12 weeks. Outcomes of interest were nutritional intake, weight status, and quality of life. (3) Results: A total of 33 outpatients were included, categorized as follows: Group A (n = 21); Group B (n = 12); severely malnourished (n = 9), moderately malnourished (n = 24), mean BMI 18.0 SD 2.5 kg/m2. No differences were observed between groups at baseline or at week 12; however, analysis of the whole cohort (Group A + B) revealed nutrition intervention resulted in significant improvements in protein intake (+25.4 SD 53.4 g/d; p = 0.040), weight (+1.1 SD 2.6 kg; p = 0.032) and quality of life (-4.4 SD 10.0; p = 0.040). Only 41.2% of Group A and 58.3% of Group B reported consuming ONSs at week 12. Adherence to ONSs was associated with weight gain (+1.9 SD 2.5 kg vs. +0.4 SD 2.5 kg; p = 0.098). (4) Conclusions: Nutritional support results in significant improvements in nutrition status and quality of life in malnourished outpatients with COPD. However, improvements are associated with adherence to ONSs, suggesting the type of ONSs and how they are provided are important considerations in clinical practice and future studies.

Factors associated with noninvasive ventilation usage in patients with hypoventilation disorders.

Study Objectives: The objective of this study was to investigate the association between demographic, clinical, and interface factors and noninvasive ventilation (NIV) usage. Methods: A retrospective cohort analysis of 478 patients prescribed NIV from 2013 to 2021 was performed. Demographic factors, clinical indications for NIV, and interface factors were collected, and linear regression was conducted to evaluate the association between these variables and NIV usage (hour/night). Results: The average usage of the cohort was 6.5 hour/night ±â€…4.6, with an average age of 57 years ±â€…16 and body mass index (BMI) of 40.5kg/m2 ±â€…14.7. The cohort was mostly male (n = 290, 60.6%). The most common indications for NIV prescription were high-pressure requirement for obstructive sleep apnea (HPR, n = 190, 39.7%), neuromuscular disease (NMD, n = 140, 29.3%), and obesity hypoventilation syndrome (OHS, n = 111, 23.2%). A diagnosis of NMD was a significant predictor of higher NIV usage (8.0 ±â€…6.1 hour/night) in multivariate analysis (p = .036). The HPR subcohort had the lowest usage of all indications. Age and BMI did not predict usage. A nasal interface (p < .01) and lower expiratory positive airway pressure (EPAP) setting (p < .001) were associated with increased NIV usage. Conclusions: This study highlights the multifaceted nature of NIV usage. Where demographic factors were not consistent predictors of usage, interface, and clinical indication were associated with usage. These findings highlight that the HPR users are a group at risk of low usage.

Power spectral analysis of the sleep electroencephalogram in positional obstructive sleep apnea.

OBJECTIVE/BACKGROUND: Previous studies have shown that obstructive sleep apnoea (OSA) is associated with reduced delta EEG and increased beta EEG power and increased EEG slowing ratio. There are however no studies that explore differences in sleep EEG between positional obstructive sleep apnoea (pOSA) and non-positional obstructive sleep apnoea (non-pOSA) patients. PATIENTS/METHODS: 556 of 1036 consecutive patients (246 of 556 were female) undertaking polysomnography (PSG) for the suspicion of OSA met the inclusion criteria for this study. We calculated power spectra of each sleep epoch using Welch's method with ten, 4-s overlapping windows. Outcome measures such as Epworth Sleepiness Scale, SF-36 Quality of Life, Functional Outcomes of Sleep Questionnaire and Pyschomotor Vigilance Task were compared between the groups. RESULTS: Patients with pOSA had greater delta EEG power in NREM and greater N3 proportions compared to their non-pOSA counterparts. There were no differences in theta (4-8Hz), alpha (8-12Hz), sigma (12-15Hz) or beta (15-25Hz) EEG power or EEG slowing ratio between the two groups. There were also no differences in the outcome measures between these two groups. The division of pOSA into spOSA and siOSA groups showed better sleep parameters in siOSA but with no difference in sleep power spectra. CONCLUSIONS: This study partially supports our hypothesis in showing that pOSA, compared to non-pOSA, is associated with increased delta EEG power but did not show any variation to beta EEG power or EEG slowing ratio. This limited improvement in sleep quality did not translate to measurable changes to outcomes, suggesting beta EEG power or EEG slowing ratio may be key factors.

Usefulness of self-administered questionnaires in screening for direct referral for polysomnography without sleep physician review.

STUDY OBJECTIVES: To evaluate self-administered screening questionnaires (Epworth Sleepiness Scale [ESS], Berlin, OSA50, and STOP-Bang questionnaires) in patients considered for polysomnography for probable obstructive sleep apnea suitable for direct polysomnography without sleep specialist review and to evaluate the usefulness of combining questionnaires in this population. METHODS: This was a retrospective review of tertiary sleep center referrals (November 2017 to April 2020) where ≥ 3 screening questionnaires were completed and type 1 polysomnography was performed. Sensitivity, specificity, positive and negative predictive values, and likelihood ratios to detect an apnea-hypopnea index (AHI) ≥ 15 or ≥ 30 events/h were calculated for each questionnaire (with or without ESS ≥ 8) or any positive questionnaire with ESS ≥ 8. RESULTS: We included 2,152 patients. The questionnaires were completed in the majority (ESS 96%, Berlin 77%, OSA50 84%, and STOP-Bang 90%) of referrals. Berlin was most sensitive (82.5% and 85% to detect AHI ≥ 15 and ≥ 30 events/h, respectively) but least specific (23% both thresholds). STOP-Bang was least sensitive (66% and 42%, respectively) but most specific (68% and 60%, respectively). Sensitivity declined for the Berlin, OSA50 and STOP-Bang questionnaires when combined with ESS ≥ 8. Combining any questionnaire with ESS ≥ 8 returned an intermediate sensitivity of 61% and 73% and a specificity of 49% and 47% for AHI ≥ 15 and ≥ 30 events/h, respectively. STOP-Bang alone was predictive of obstructive sleep apnea on multivariate analysis but was only associated with a clinically nonsignificant positive likelihood ratio. However, STOP-Bang is associated with unacceptable false-positive and -negative rates, which did not support its use. CONCLUSIONS: Self-administered questionnaires are inadequate in patients under consideration for polysomnography and should not be used as clinical support for suitability of direct polysomnography without sleep specialist review. Combining questionnaires causes deteriorated performance. CITATION: Hukins C, Duce B. Usefulness of self-administered questionnaires in screening for direct referral for polysomnography without sleep physician review. J Clin Sleep Med. 2022;18(5):1405-1412.

Association between early stage N2 sleep spindle burst characteristics and vigilance groups: an observational study on patients from a tertiary sleep centre.

Objective.Obstructive sleep apnoea (OSA) is associated with impaired vigilance. This paper examines the hypothesis that sleep spindle (Sp) characteristics during nocturnal sleep can be mapped to vigilance deficits measured by the psychomotor vigilance task (PVT) in patients with OSA.Approach.The PVT was performed prior to In-laboratory Polysomnography for 250 patients. PVT outcomes were clustered into three vigilance groups (VGs). Spindles were scored manually for a Training Cohort of 55 patients, (9491 Sps) across different blocks of NREM sleep (SBs) and validated in a Test Cohort (25 patients, 4867 Sps). We proposed a novel set of Sp features including a spindle burst index (SBI), which quantifies the burst characteristics of spindles and constructed models mapping them to VGs. We also explored the performance of conventional Sp features (such as Sp number and density) in our modelling approach.Main results.In the Training Cohort, we observed statistically significant differences in the SBI across VGs and SBs independent of OSA severity (1st stage N2 SBI;p= <0.001 across VGs). In the Test Cohort, a Model based on the proposed SBI predicted VG membership with 88% accuracy. A model based on conventional Sp features mapped to VGs with 80% accuracy, and a model using mixed burst and conventional features reached an accuracy of 88%.Significance.Spindle features measured during diagnostic In-laboratory polysomnography measurements can be mapped to PVT outcomes. The novel SBI proved useful for exploring the relationship between PVT outcomes and sleep. Further studies in larger populations are needed to verify these conclusions.

Randomized controlled trial on the efficacy of audio-visual health educational materials on CPAP adherence: the AHEAD trial.

STUDY OBJECTIVES: Educational interventions have been proposed to improve continuous positive airway pressure (CPAP) adherence; however, studies to date have not demonstrated robust effectiveness, due to methodological issues. Furthermore, these educational interventions have not specifically targeted low health literacy communication techniques, which have been demonstrated to improve outcomes in numerous other chronic diseases. We hypothesized that the addition of low-cost audio-visual educational videos (EVs) to usual standard-of-care (SC) education would improve CPAP adherence in adults with obstructive sleep apnea (OSA) syndrome. METHODS: At CPAP initiation, treatment-naïve adults with OSA syndrome were randomized to (1) usual SC or (2) SC + 5 EVs showing a patient's journey, designed with low health literacy communication techniques to teach patients about OSA and CPAP therapy. The primary endpoint was CPAP usage at 2 months (hours/night) and secondary endpoints were CPAP usage at 12 months and percentage of patients with ≥ 4 hours/night use at 2 months and 12 months. RESULTS: One hundred and ninety-five patients were randomized (SC 99, EV 96), with a mean age of 57 years (interquartile range [IQR] 44.1-64.8 years). There were no statistically significant differences in patient characteristics at baseline between the SC vs EV groups, with the diagnostic apnea-hypopnea index of 34 events/h (IQR 21-59 events/h) vs 30 events/h (IQR 20-50 events/h) and Epworth Sleepiness Scale score of 12.8 ± 6 vs 11.7 ± 5. At 2 months, there was no significant difference in hours of CPAP usage (SC: 3.45 hours/night [95% confidence interval (CI): 2.76 to 4.13] vs EV: 3.75 hours/night [95% CI: 3.14 to 4.37]) nor in proportion with adequate usage or overall commencement rate. However, at 12 months, there was a significant difference in hours of CPAP usage (SC: 2.50 hours/night [95% CI: 1.94 to 3.06] vs EV: 3.66 hours/night [95% CI: 2.92 to 4.40]). The probability of adequate CPAP usage at 12 months was higher in the intervention arm (odds ratio: 1.33; 95% CI: 1.04 to 1.7; P = .013). Patients with low education backgrounds benefitted substantially from the EV intervention compared with SC (mean difference at 12 months = 2.47 hours/night usage; 95% CI: 1.01 to 2.93; P < .01). CONCLUSIONS: Low health literacy-designed EVs improve CPAP adherence at 12 months compared with SC, with the greatest impact in patients with a low educational background. CLINICAL TRIAL REGISTRATION: Registry: Australian New Zealand Clinical Trials Registry; Name: Randomised controlled trial on the efficacy of audio-visual health educational materials on sleep health literacy and continuous positive airway pressure (CPAP) adherence in Sleep Clinic patients; URL: https://www.australianclinicaltrials.gov.au/anzctr/trial/ACTRN12619000523101; Identifier: ACTRN12619000523101. CITATION: Ellender CM, Samaranayake C, Reid N, et al. Randomized controlled trial on the efficacy of audio-visual health educational materials on CPAP adherence: the AHEAD trial. J Clin Sleep Med. 2022;18(11):2617-2625.

Asset life span in a government funded CPAP device program.

STUDY OBJECTIVES: To determine the life span of devices in a government long-term continuous positive airway pressure (CPAP) device loan program. METHODS: Retrospective review of CPAP devices provided under the Queensland Health Sleep Disorders program in Queensland, Australia, from data recorded in an in-house database that has collected data since 1995. Primary outcomes were hours of use and age of device at end-of-life. Device survival analysis was performed collectively for all devices and for different models. Reasons for device end-of-life were compared between models. RESULTS: There were 9,222 CPAP devices provided on long-term loan over this period, with asset end-of-life date available in 90%. Median life span was 15,178 hours (interquartile range 8,167-20,296 hours) and 12.4 (interquartile range 7.6-18.8) years. Five percent of devices were condemned in the first 3 years, and 13% of devices were condemned in the first 5 years. There were significant differences in survival patterns between different models, but after correction for run hours, only one model differed (related to manufacturer policy to replace not repair equipment). Reasons for end-of-life differed between models (P < .001) with manufacturer recall, excessive noise and faulty buttons the most common reasons. CONCLUSIONS: Government CPAP loan programs can develop asset management plans with an anticipated average asset life span of 15,178 hours or 12.4 years; however, they should also plan for the need to replace equipment where earlier failure occurs. Early equipment failures are seen with variability between models, and appropriate warranty periods to cover these early failures should be negotiated with manufacturers.

Adequate health literacy is associated with adherence to continuous positive airway pressure in adults with obstructive sleep apnea.

Study Objectives: Obstructive sleep apnea (OSA) is a chronic disease with significant health implications and adequate adherence to continuous positive airway pressure (CPAP) is essential for effective treatment. In many chronic diseases, health literacy has been found to predict treatment adherence and outcomes. In this study, the aim was to determine the health literacy of a sleep clinic population and evaluate the association between health literacy and CPAP adherence. Methods: A prospective cohort study was undertaken, recruiting 104 consecutive patients with a variety of sleep diagnoses. The Short Form Rapid Estimate of Adult Literacy in Medicine (REALM-SF), a validated questionnaire, was administered to measure health literacy. In a sub-group of 91 patients prescribed CPAP for OSA, CPAP usage was measured, with adequate usage defined as greater than 4 h/night CPAP therapy. Results: Seventy-one percent of the sleep clinic cohort was found to have adequate health literacy, as measured by the REALM-SF. In those prescribed CPAP for OSA, inadequate health literacy was associated with a twofold increased risk for inadequate CPAP usage (adjusted odds ratio [OR] 2.9, 95% CI: 1.1 to 8.22, p = 0.045). There was a 1.7 h/night difference in median CPAP usage comparing those with adequate to inadequate health literacy (4.6 h vs. 6.3 h/night). Conclusions: The majority of this sleep disorders cohort had adequate health literacy as measured by the REALM-SF questionnaire. However, inadequate health literacy appears to be an independent predictor of treatment adherence and may represent a modifiable risk factor of poor treatment outcomes in OSA.

Sleep-disordered breathing in spinal cord-injured patients: a short-term longitudinal study.

UNLABELLED: Spinal cord-injured subjects were assessed during the acute admission for sleep-disordered breathing. Polysomnography demonstrated a high incidence of sleep apnoea that persisted during the acute phase. There was no correlation with respiratory function tests or measures of ventilatory control. Screening of this population is worthwhile although the clinical significance is uncertain. BACKGROUND AND OBJECTIVE: Previous studies have demonstrated an increased incidence of sleep apnoea in spinal cord-injured patients. Many of these studies were performed in long-term, stable spinal cord injury (SCI). The aims of this study were: (i) to determine the prevalence of sleep-disordered breathing (SDB) in acute SCI; (ii) to document the change in SDB over time during the rehabilitation period; and (iii) to correlate the degree of SDB with ventilatory parameters. METHODS: Sixteen subjects with an acute SCI level T12 and above with complete motor impairment (American Spinal Injury Association impairment scale A or B) were recruited. Assessment, including polysomnography, respiratory function testing, and hypoxic and hypercapnic ventilatory responses, were performed 6-8 weeks post SCI, and repeated 6 months post SCI. RESULTS: Eleven of 16 subjects (73%) had evidence of sleep apnoea, five of whom were moderate to severe. This high incidence persisted during the acute admission, with 9 of 12 subjects (75%) having sleep apnoea on polysomnography 20 weeks following injury. There was no correlation between the severity of SDB and other measures, such as level or completeness of injury, respiratory function tests or measures of ventilatory responses. CONCLUSIONS: We have demonstrated a high incidence of sleep apnoea in the acute phase of SCI that persisted during the acute admission. Despite the high incidence of sleep apnoea, patients were relatively asymptomatic. Screening of this population would appear worthwhile given the high prevalence, although the significance of the sleep apnoea and clinical impact is not known.

Overnight airway obstruction severity prediction centered on acoustic properties of smart phone: validation with esophageal pressure.

OBJECTIVE: Obstructive sleep apnea is characterized by a number of airway obstructions. Esophageal pressure manometry (EPM) based estimation of consecutive peak to trough differences (ΔPes) is the gold standard method to quantify the severity of airway obstructions. However, the procedure is rarely available in sleep laboratories due to invasive nature. There is a clinical need for a simplified, scalable technology that can quantify the severity of airway obstructions. In this paper, we address this and propose a pioneering technology, centered on sleep related respiratory sound (SRS) to predict overnight ΔPes signal. APPROACH: We recorded streams of SRS using a bedside iPhone 7 smartphone from subjects undergoing diagnostic polysomnography (PSG) studies and EPM was performed concurrently. Overnight data was divided into epochs of 10 s duration with 50% overlap. Altogether, we extracted 42 181 such epochs from 13 subjects. Acoustic features and features from the two PSG signals serve as an input to train a machine learning algorithm to achieve mapping between non-invasive features and ΔPes values. A testing dataset of 14 171 epochs from four new subjects was used for validation. MAIN RESULTS: The SRS based model predicted the ΔPes with a median of absolute error of 6.75 cmH2O (±0.59, r = 0.83(±0.03)). When information from the PSG were combined with the SRS, the model performance became: 6.37cmH2O (±1.02, r = 0.85(±0.04)). SIGNIFICANCE: The smart phone based SRS alone, or in combination with routinely collected PSG signals can provide a non-invasive method to predict overnight ΔPes. The method has the potential to be automated and scaled to provide a low-cost alternative to EPM.