Cardio-Respiratory Sleep Studies at Home:Experience in Research and Clinical Cohorts

Objective To evaluate the success rates of home cardiorespiratory polygraphy in children under investigation for sleep-disordered breathing and parent perspectives on equipment use at home. Design Prospective observational study. Setting Sheffield, Evelina London and Southampton Children's Hospitals. Patients Data are reported for 194 research participants with Down syndrome, aged 0.5-5.9 years across the three centres and 61 clinical patients aged 0.4-19.5 years from one centre, all of whom had home cardiorespiratory polygraphy including respiratory movements, nasal pressure flow, pulse oximetry, body position and motion. Main outcome measures Percentage of home cardiorespiratory studies successfully acquiring ≥4 hours of artefact-free data at the first attempt. Parental report of ease of use of equipment and preparedness to repeat home diagnostics in the future. Results 143/194 (74%; 95% CI 67% to 79%) of research participants and 50/61 (82%; 95% CI 71% to 90%) of clinical patients had successful home cardiorespiratory polygraphy at the first attempt. Some children required multiple attempts to achieve a successful study. Overall, this equated to 1.3 studies per research participant and 1.2 studies per clinical child. The median artefact-free sleep time for successful research studies was 515 min (range 261-673) and for clinical studies 442 min (range 291-583). 84% of research and 87% of clinical parents expressed willingness to repeat home cardiorespiratory polygraphy in the future. 67% of research parents found the equipment 'easy or okay' to use, while 64% of clinical parents reported it as 'easy' or 'very easy'. Conclusions Home cardiorespiratory polygraphy offers an acceptable approach to the assessment of sleep-disordered breathing in children.</p

Predicting sleep disordered breathing in outpatients with suspected OSA

Objective To validate the utilities of Berlin, STOP and STOP-BANG Questionnaires, other patient characteristics, comorbidities, Epworth Sleepiness Scale (ESS), fractional exhaled nitric oxide (FENO) and blood markers for the prediction of sleep disordered breathing (SDB) on limited polygraphy. Setting North Glasgow Sleep Service (a tertiary referral centre). Participants 129 consecutive patients, aged ≥16 years, referred to the sleep clinic for assessment of possible obstructive sleep apnoea. Interventions We selected cut-points of apnoea hypopnoea index (AHI) of ≥5 and ≥15/h from their home polygraphy and determined associations of these with individual symptoms, questionnaire scores and other results. Receiver operating characteristic analysis and univariate and multivariate logistic regression were used to explore these. Primary and secondary outcomes measures Primary: The utility of STOP, STOP-BANG and Berlin Questionnaires for prediction of SDB. Secondary: The utility of other measures for prediction of SDB. Results AHI was ≥5 in 97 patients and ≥15 in 56 patients. STOP and STOP-BANG scores were associated with both AHI cut-points but results with ESS and Berlin Questionnaire scores were negative. STOP-BANG had a negative predictive value 1.00 (0.77–1.00) for an AHI ≥15 with a score ≥3 predicting AHI ≥5 with sensitivity 0.93 (95% CI 0.84 to 0.98) and accuracy 79%, while a score ≥6 predicted AHI ≥15 with specificity 0.78 (0.65 to 0.88) and accuracy 72%. Neck circumference ≥17 inch and presence of witnessed apnoeas were independent predictors of SDB. Conclusions STOP and STOP-BANG Questionnaires have utility for the prediction of SDB in the sleep clinic population. Modification of the STOP-BANG Questionnaire merits further study in this and other patient groups.</p

Resistant/Refractory Hypertension and Sleep Apnoea: Current Knowledge and Future Challenges

Hypertension is one of the most frequent cardiovascular risk factors. The population of hypertensive patients includes some phenotypes whose blood pressure levels are particularly difficult to control, thus putting them at greater cardiovascular risk. This is especially true of so-called resistant hypertension (RH) and refractory hypertension (RfH). Recent findings suggest that the former may be due to an alteration in the renin–angiotensin–aldosterone axis, while the latter seems to be more closely related to sympathetic hyper-activation. Both these pathophysiological mechanisms are also activated in patients with obstructive sleep apnoea (OSA). It is not surprising, therefore, that the prevalence of OSA in RH and RfH patients is very high (as reflected in several studies) and that treatment with continuous positive airway pressure (CPAP) manages to reduce blood pressure levels in a clinically significant way in both these groups of hypertensive patients. It is therefore necessary to incorporate into the multidimensional treatment of patients with RH and RfH (changes in lifestyle, control of obesity and drug treatment) a study of the possible existence of OSA, as this is a potentially treatable disease. There are many questions that remain to be answered, especially regarding the ideal combination of treatment in patients with RH/RfH and OSA (drugs, renal denervation, CPAP treatment) and patients’ varying response to CPAP treatment

The effect of longitudinal sleep monitoring on clinician agreement in obstructive sleep apnea diagnosis: The ELSA study

There is strong evidence for clinically relevant night‐to‐night variability of respiratory events in patients with suspected obstructive sleep apnea. Sleep experts retrospectively evaluated diagnostic data in 56 patients with suspected obstructive sleep apnea. Experts were blinded to the fact that they were diagnosing the same case twice, once based on a short report of a single in‐laboratory respiratory polygraphy and once with the additional information of 14 nights of pulse oximetry at home. All experts (n = 22) were highly qualified, 13 experts (59.1%) treated > 100 patients with suspected obstructive sleep apnea per year. In 12 patients, the apnea–hypopnea index in the respiratory polygraphy was  100 per year compared with 0–29 patients per year (Coef. [95% confidence interval] −0.63 [−1.22/−0.04] and −0.61 [−1.07/−0.15], respectively). Experts found already a high level of consensus regarding obstructive sleep apnea diagnosis, severity and continuous positive airway pressure recommendation after a single respiratory polygraphy. However, longitudinal sleep monitoring could help increase consensus in selected patients with diagnostic uncertainty

Oximetry Alone Versus Portable Polygraphy for Sleep Apnea Screening Before Bariatric Surgery

Background: Screening for obstructive sleep apnea (OSA) is recommended as part of the preoperative assessment of obese patients scheduled for bariatric surgery. The objective of this study was to compare the sensitivity of oximetry alone versus portable polygraphy in the preoperative screening for OSA. Methods: Polygraphy (type III portable monitor) and oximetry data recorded as part of the preoperative assessment before bariatric surgery from 68 consecutive patients were reviewed. We compared the sensitivity of 3% or 4% desaturation index (oximetry alone) with the apnea-hypopnea index (AHI; polygraphy) to diagnose OSA and classify the patients as normal (30 events per hour). Results: Using AHI, the prevalence of OSA (AHI > 10 per hour) was 57.4%: 16.2% of the patients were classified as severe, 41.2% as mild to moderate, and 42.6% as normal. Using 3% desaturation index, 22.1% were classified as severe, 47.1% as mild to moderate, and 30.9% as normal. With 4% desaturation index, 17.6% were classified as severe, 32.4% as mild, and 50% as normal. Overall, 3% desaturation index compared to AHI yielded a 95% negative predictive value to rule out OSA (AHI > 10 per hour) and a 100% sensitivity (0.73 positive predictive value) to detect severe OSA (AHI > 30 per hour). Conclusions: Using oximetry with 3% desaturation index as a screening tool for OSA could allow us to rule out significant OSA in almost a third of the patients and to detect patients with severe OSA. This cheap and widely available technique could accelerate preoperative work-up of these patient

The feasibility of the Emfit movement sensor as an automated screening tool for sleep apnea in the ischemic stroke patients

Stroke is a common cause of death and a major reason for disability. Stroke survivors can have very difficult symptoms and require very intensive and expensive rehabilitation. Sleep disordered breathing, sleep apnea, is common among stroke patients, it's a high risk factor for recurrent stroke and untreated sleep apnea has a negative influence on the stroke recovery. All stroke patients are recommended to be measured for sleep apnea, but the lack of resources don't allow it. Therefore there is a need for a screening tool to find the stroke patients who need the measurement most and who benefit the most of the treatment of the sleep apnea. We studied the possibility to use the Emfit movement sensor combined with a pulse oximeter as a screening tool. The Emfit movement sensor doesn't have connections to the patient, therefore it wouldn't require lots of resources to set up the measurement and there are no contacts that can cause interference during the measurement. The automatic scoring of the measurement would remove the need for an expert to manually score every measurement. The test subjects were measured at the same night using both the Emfit movement sensor and a conventional respiratory polygraphy device. The Emfit movement sensor and the standard respiratory polygraphy measurements were scored using Noxturnal's automatic analysis tool and the results were compared. The results were also compared to the manual scoring of the standard respiratory polygraphy. The Emfit movement sensor measurement slightly overestimates the apnea hypopnea index, as does the automatically scored standard respiratory polygraphy too. The automatic analysis ability to detect correctly the duration and timing of a respiratory event in the Emfit movement sensor measurement seems to depend on the amount of noise in the measurement. Our study indicates that the Emfit movement sensor has potential to be used as a screening tool for sleep apnea in the ischemic stroke patients, but the automatic analysis still needs improvements to provide more accurate results

Obstructive Sleep Apnoea Syndrome, Endothelial Function and Markers of Endothelialization. Changes after CPAP

STUDY OBJECTIVES: This study tries to assess the endothelial function in vivo using flow-mediated dilatation (FMD) and several biomarkers of endothelium formation/restoration and damage in patients with obstructive sleep apnoea (OSA) syndrome at baseline and after three months with CPAP therapy. DESIGN: Observational study, before and after CPAP therapy. SETTING AND PATIENTS: We studied 30 patients with apnoea/hypopnoea index (AHI) >15/h that were compared with themselves after three months of CPAP therapy. FMD was assessed non-invasively in vivo using the Laser-Doppler flowmetry. Circulating cell-free DNA (cf-DNA) and microparticles (MPs) were measured as markers of endothelial damage and the vascular endothelial growth factor (VEGF) was determined as a marker of endothelial restoration process. MEASUREMENTS AND RESULTS: After three month with CPAP, FMD significantly increased (1072.26 ± 483.21 vs. 1604.38 ± 915.69 PU, p< 0.005) cf-DNA and MPs significantly decreased (187.93 ± 115.81 vs. 121.28 ± 78.98 pg/ml, p<0.01, and 69.60 ± 62.60 vs. 39.82 ± 22.14 U/μL, p<0.05, respectively) and VEGF levels increased (585.02 ± 246.06 vs. 641.11 ± 212.69 pg/ml, p<0.05). These changes were higher in patients with more severe disease. There was a relationship between markers of damage (r = -0.53, p<0.005) but not between markers of damage and restoration, thus suggesting that both types of markers should be measured together. CONCLUSIONS: CPAP therapy improves FMD. This improvement may be related to an increase of endothelial restoration process and a decrease of endothelial damage

Early diagnosis of sleep related breathing disorders

Obstructive sleep apnea (OSA) being the most frequent sleep related breathing disorder results in non-restorative sleep, an increased cardiovascular morbidity and mortality as well as an elevated number of accidents. In Germany at least two million people have to be expected. If obstructive sleep apnea is diagnosed early enough then sleep may regain its restorative function, daytime performance may be improved and accident risk as well as cardiovascular risk may be normalised. This review critically evaluates anamnestic parameters, questionnaires, clinical findings and unattended recordings during sleep regarding their diagnostic accurracy in recognising OSA

Sleep-disordered breathing in patients with implanted cardiac devices: validation of the ApneaScanTM algorithm and implications for prognosis

Aims Sleep-disordered breathing (SDB) is common in heart failure (HF) and frequently undiagnosed. The ApneaScanTM algorithm, available on certain ICD and CRT devices, uses changes in transthoracic impedance with breathing to quantify SDB. This research tests 3 hypotheses: 1) The ApneaScanTM algorithm can accurately detect moderate-to-severe SDB in patients with HF 2) There is minimal night-to-night variability in the ApneaScanTM-determined severity of SDB 3) Those with moderate-to-severe SDB, assessed by ApneaScanTM, have a higher rate of adverse cardiovascular events than those without. Methods Patients with EF≤40% and ICD or CRT devices incorporating ApneaScanTM were recruited. For hypothesis 1, 54 subjects underwent a successful sleep polygraphy study and simultaneous download of ApneaScanTM data. 22 subjects (44%) had undiagnosed moderate-to-severe SDB. The area under the ROC curve was 0.84 for the diagnosis of moderate-to-severe SDB. The optimal ApneaScan cut-off was 30.5/hour (sensitivity 95%, specificity 69%, positive predictive value 68%, negative predictive value 95%). For hypothesis 2, ApneaScanTM data over 28- and 92-nights in 35 patients was reviewed. There was minimal variability in SDB and no significant difference between durations. For hypothesis 3, 72 patients were followed up at a median of 532 (IQR 386-736) days.Mean event-free survival was 660±344 days (95% CI 535-785 days) in the insignificant SDB group and 854±413 days (95% CI 730-978 days) in the significant SDB group (p=0.25 by log rank test). Conclusions ApneaScanTM, with an optimal cut-off of 30.5 events/hour, is a sensitive means of screening for SDB in patients with HF with a high negative predictive value. Readings above 30.5/hour require further investigation with a sleep study. Night-to-night variability in SDB is minimal and repeat sleep studies should be reserved for those with ‘borderline’ AHI. In this cohort, the presence of SDB was not associated with adverse cardiovascular outcomes. Recruitment is on-going to test this further.Open Acces