Emmanouil Vagiakis

Randomised trial of nasal surgery for fixed nasal obstruction in obstructive sleep apnoea

Although nasal surgery has limited efficacy in obstructive sleep apnoea (OSA) treatment, some patients experience improvement. The present study tested the hypothesis that post-surgery improvement is associated with increased nasal breathing epochs. A total of 49 OSA patients (mean apnoea/hypopnoea index (AHI) 30.1±16.3 events·h−1) with symptomatic fixed nasal obstruction due to deviated septum were randomly assigned to either septoplasty (surgery group; 27 patients) or sham surgery (placebo group; 22 patients). The breathing route was examined during overnight polysomnography. All patients in the placebo group were nonresponders, whereas in the surgery group four (14.8%) patients were responders and exhibited considerable increase in nasal breathing epochs (epochs containing more than three consecutive phasic nasal signals), and 23 patients were nonresponders, presenting a modest increase in nasal breathing epochs. The change in AHI was inversely related to the change in nasal breathing epochs, with responders exhibiting among the greatest increases in nasal breathing epochs. Baseline nasal breathing epochs were positively related to per cent change in AHI. Responders had among the lowest baseline nasal breathing epochs; a cut-off value of 62.4% of total sleep epochs best separated (100% sensitivity, 82.6% specificity) responders/nonresponders. In conclusion, nasal surgery rarely treats obstructive sleep apnoea effectively. Baseline nasal breathing epochs can predict the surgery outcome.

Nasal inflammation in sleep apnoea patients using CPAP and effect of heated humidification

Nasal continuous positive airway pressure (CPAP) can cause undesirable nasal symptoms, such as congestion to obstructive sleep apnoea (OSA) patients, whose symptoms can be attenuated by the addition of heated humidification. However, neither the nature of nasal symptoms nor the effect of heated humidification on nasal pathophysiology and pathology are convincingly known. 20 patients with OSA on nasal CPAP who exhibited symptomatic nasal obstruction were randomised to receive either 3 weeks of CPAP treatment with heated humidification or 3 weeks of CPAP treatment with sham-heated humidification, followed by 3 weeks of the opposite treatment, respectively. Nasal symptom score, nasal resistance, nasal lavage interleukin-6, interleukin-12 and tumour necrosis factor-&agr; and nasal mucosa histopathology were assessed at baseline and after each treatment arm. Heated humidification in comparison with sham-heated humidification was associated with decrease in nasal symptomatology, resistance and lavage cytokines, and attenuation of inflammatory cell infiltration and fibrosis of the nasal mucosa. In conclusion, nasal obstruction of OSA patients on CPAP treatment is inflammatory in origin and the addition of heated humidification decreases nasal resistance and mucosal inflammation.

Obstructive sleep apnoea and oral breathing in patients free of nasal obstruction

Although there is an association between nasal obstruction, oral breathing and obstructive sleep apnoea syndrome (OSAS), it remains unknown whether increased oral breathing occurs in patients with OSAS who are free of nasal obstruction. The present study evaluated the relationship between breathing route and OSAS in patients without nasal obstruction. The breathing route of 41 snorers (25 male; aged 26–77 yrs) with normal nasal resistance was examined during overnight polysomnography using a nasal cannula/pressure transducer and an oral thermistor. In total, 28 patients had OSAS (apnoeics) and 13 patients were simple snorers. Apnoeics had a higher percentage of oral and oro-nasal breathing epochs. Oral and oro-nasal breathing epochs were positively related with apnoea/hypopnoea index (AHI) and duration of apnoeas/hypopnoeas and inversely related to oxygen saturation. Additionally, oro-nasal breathing epochs correlated with body mass index (BMI). In multiple linear regression analysis, oral breathing epochs were independently related only to AHI (r2 = 0.443), and oro-nasal breathing epochs were independently related to AHI (r2 = 0.736) and BMI (r2 = 0.036). In conclusion, apnoeics spent more time breathing orally and oro-nasally than simple snorers, and the apnoea/hypopnoea index is a major determinant of the time spent breathing orally and oro-nasally.

Predictors of residual sleepiness in adequately treated obstructive sleep apnoea patients

Some patients with obstructive sleep apnoea syndrome (OSAS; respiratory distress index (RDI) of >5 events·h−1) experience residual excessive daytime subjective sleepiness (Epworth Sleepiness Scale (ESS) score of >10), despite adequate use of continuous positive airway pressure (CPAP) therapy. The aim of the present study was to identify clinical and polysomnographic predictors of this sleepiness. Clinical and polysomnographic variables and ESS score were evaluated in 208 OSAS patients with an ESS score of >10 before (initial assessment) and after ≥6 months of adequate (≥4 h·day−1) CPAP use. Following CPAP treatment, 114 (55%) patients showed an abnormal ESS score (>10; CPAP nonresponders), whereas 94 (45%) showed a normal ESS score (<11; CPAP responders). Of the CPAP responders, none had a history of depression, whereas the converse was true for 38.8% of CPAP nonresponders. In addition, multivariate logistic regression analysis revealed that the independent predictors of residual excessive daytime sleepiness following CPAP therapy were a history of diabetes and heart disease, and a higher ESS score and lower RDI on initial assessment. In conclusion, predictors of residual excessive sleepiness in adequately CPAP-treated OSAS were a history of depression, diabetes and heart disease, and a higher ESS score and lower RDI on initial assessment.

Determinants of subjective sleepiness in suspected obstructive sleep apnoea

Although daytime sleepiness is commonly associated with obstructive sleep apnoea (OSA), the relationship between OSA severity and subjective sleepiness has been documented elusive. This study aimed to identify clinical and polysomnographic determinants of subjective sleepiness among patients suspected of having OSA. A sleep clinic‐based sample of 915 patients was interviewed with a structured questionnaire and underwent diagnostic overnight polysomnography. Subjective sleepiness was quantified by Epworth Sleepiness Scale (ESS). Excessive daytime sleepiness (defined as ESS score > 10) was present in 38.8% of patients. In multiple linear regression analysis, respiratory disturbance index [RDI; used to define (whenever RDI was >5) and quantify OSA], depression and diabetes were the most important determinants of ESS score accounting for 17%, 11% and 6% of its variability respectively. Chronic obstructive pulmonary disease (COPD), stroke, heart disease, alcohol use and body mass index were less important determinants of ESS score explaining 1–3% of its variability. In conclusion, OSA should not be considered the sole potential cause of increased subjective sleepiness in patients suspected of having OSA. Primarily depression and diabetes, but also COPD, stroke, heart disease, alcohol use and increased body mass index may contribute to increased subjective sleepiness.

The effect of nasal tramazoline with dexamethasone in obstructive sleep apnoea patients

Although there is a strong correlation between oral/oro-nasal breathing and apnoea/hypopnoea index in patients with obstructive sleep apnoea and normal nasal resistance at wakefulness, it remains unknown whether the pharmacological prevention of potential nasal obstruction during sleep could decrease oral/oro-nasal breathing and increase nasal breathing and subsequently decrease the apnoea/hypopnoea index. This study evaluated the effect of a combination of a nasal decongestant with corticosteroid on breathing route pattern and apnoea/hypopnoea index. 21 patients with obstructive sleep apnoea (mean apnoea/hypopnoea index 31.1 events per hour) and normal nasal resistance at wakefulness were enrolled in a randomised crossover trial of 1 weeks’ treatment with nasal tramazoline and dexamethasone compared with 1 weeks’ treatment with nasal placebo. At the start and end of each treatment period, patients underwent nasal resistance measurement and overnight polysomnography with attendant measurement of breathing route pattern. Nasal tramazoline with dexamethasone was associated with decrease in oral/oro-nasal breathing epochs and concomitant increase in nasal breathing epochs, and mean decrease of apnoea/hypopnoea index by 21%. The change in nasal breathing epochs was inversely related to the change in apnoea/hypopnoea index (Rs=0.78; p<0.001). In conclusion, nasal tramazoline with dexamethasone in OSA patients with normal nasal resistance at wakefulness can restore the preponderance of nasal breathing epochs and modestly improve apnoea/hypopnoea index. Nasal tramazoline with dexamethasone in OSA patients can restore nasal breathing epochs and improve AHI modestly http://ow.ly/mxu4T

Heart rate variability is augmented in patients with positional obstructive sleep apnea, but only supine LF/HF index correlates with its severity

PurposeData on cardiac autonomic functioning, as expressed by heart rate variability (HRV), in patients with positional obstructive sleep apnea (p-OSA) disorder are lacking. The purpose of the study was to compare HRV indices between sleep segments derived from supine body position and another body position with and without apneic events, respectively. Our intention was to find some correlation between HRV indices and the pathophysiological characteristics of the corresponding temporal period.MethodsNocturnal polysomnograms derived from twenty-seven patients (22 men) with documented positional apnea were retrospectively reviewed. Patients never treated for OSA and free from diseases/drugs altering HRV were examined. Data from total sleep studies were collected. Two N2 sleep segments, from supine body position with sleep-disordered breathing (SDB) and another body position without SDB were analyzed. Apneic events (namely, apneas, hypopneas, and respiratory effort-related arousals (RERAs)), arousals, number of desaturations, minimum pulse oximetry (SaO2min), time domain variables (average RR, SDNN, SDSD, RMSSD, pNN50, and HRV triangular index) and frequency domain variables (VLF, LF, HF, TP, LF/HF) were recorded for both temporal periods.ResultsWith the exception of average RR and HF, all other variables were significantly higher in segments with SDB. Only LF/HF_supine ratio was positively correlated with the apneic_supine_index (t = 3.13, p < 0.01) and negatively correlated with SaO2min (t = −2.9, p < 0.01) and the desaturation_supine_index (t = −2.5, p = 0.02). Arousals were negatively correlated with SaO2min (t = −2.8, p < 0.01).ConclusionsSDB augments autonomic tone in patients with p-OSA, but only LF/HF correlates with its severity and might be used as a screening tool in the future. On the contrary, parasympathetic tone, as reflected by HF, remains constant in both periods.

Complex sleep apnea after full-night and split-night polysomnography: the Greek experience

PurposeTreatment-emergent central sleep apnea (TE-CSA) is defined as the emergence or persistence of central respiratory events during the initiation of positive airway pressure (PAP) without a back-up rate in obstructive sleep apnea (OSA) patients and after significant resolution of obstructive events. Previous studies have estimated a prevalence from 0.56 to 20.3%. The aim of this study was to establish the prevalence of TE-CSA in a Greek adult population.MethodsOne thousand fifty nine patients with newly diagnosed OSA, who were referred to the Sleep Disorders Center of Evangelismos Hospital of Athens over an 18-month period, were included in this study. A split-night polysomnography (PSG), or two formal overnight PSGs (diagnostic and continuous PAP (CPAP) titration study), were performed.ResultsPatients with OSA were divided in two groups; the first group included 277 patients, who underwent two separate studies (diagnostic and CPAP titration study), and the second group 782 patients, who underwent split-night studies. The prevalence of TE-CSA in the first group was 2.53% (7 patients), and in the second group was 5.63% (44 patients).ConclusionsThe prevalence of TE-CSA in Greece was lower compared to most previous reported studies. The significant variation in the prevalence of TE-CSA between different centers throughout the world is mainly associated with the used diagnostic criteria as well as methodological and technical aspects.

Resolution of apnoeas in slow wave sleep

Dear Editor: Obstructive sleep apnoea (OSA) is a prevalent disorder, which is associated with excessive daytime sleepiness, and with an increased risk for hypertension, cardiovascular, and cerebrovascular incidents, and type II diabetes. The gold standard for the evaluation of OSA is the polysomnography and the resulting apnoea-hypopnoea index (AHI), which corresponds to the total number of complete or partial upper airway obstructive events lasting 10 s or more, divided by total sleep time. AHI is known to be strongly influenced by factors such as sleep posture, head position, and sleep stage. Indeed, it has been reported that OSA worsens during rapid eye movement (REM) sleep and improves during slow wave sleep [1]. However, the studies which have examined the effect of slow wave sleep on the number of apnoeas included relatively small number of rather selected patients [1–3] and demonstrated considerably variable results ranging from complete resolution in some patients to a modest decrease in some others. Thus, it is plausible to suggest that the importance of this effect has been poorly assessed [3]. Understanding the extent of slow wave sleep-mediated improvements in OSA could ultimately lead to new therapeutic approaches for this disorder. Therefore, the purpose of this study was to investigate the effect of slow wave sleep on the frequency of respiratory events in a large cohort of consecutive patients referred for the investigation of possible OSA. Patients screened for the current prospective cohort study were all consecutive subjects who referred to the Center of Sleep Disorders of “Evangelismos” General Hospital of Athens for sleep-disordered breathing between January 2012 and February 2013. Inclusion criteria were an AHI >5 events·h and central apnoeas ≤5 % of total apnoeas at baseline diagnostic full-night polysomnography (EMBLA S7000, Medcare Flaga, Iceland). Exclusion criterion was <15 consecutive minutes of sleep stages N2, N3, and REM in supine or lateral sleep position. In order to investigate the effect of body position, sleep stage, and their interaction on AHI, we performed repeated-measures two-way analysis of variance followed by the Scheffé test for post hoc analyses. The level of significance was set at p<0.05. Among 652 patients screened, 223 did not meet the inclusion criteria (211 had AHI ≤5 events·h and 12 had central apnoeas >5 % of total apnoeas). Of 429 eligible patients, 195 were excluded from analysis because they had <15 consecutive minutes of sleep stages N2, N3, or REM in supine or lateral sleep position. The resulting cohort was composed of 234 patients (152 men) aged (mean±SD) 52.0±11.5 years, with body mass index 31.0±5.9 kg·m. At the full-night polysomnography, their total sleep time (TST) was 309± 90 min, sleep efficiency was 87.6±12.9 %, and AHI was 22.6±19.5 events·h (AHI in supine and lateral positions was 34.1±27.2 and 12.6±18.0 events·h, respectively). Time spent in N1 was 24.5±12.5 (8.0±4.3 % of TST), time spent in N2 was 172.1±58.8 min (57.1±14.3 % of TST), time spent in N3was 61.1±40.0 min (19.3±10.2% of TST), and time spent in REM sleep was 51.3±34.8 min (15.6±8.9 % of TST). AHI in supine position was 36.5±29.1, 0.3±0.9, and 35.1 ±31.2 events·h in N2, N3, and REM sleep, respectively. AHI in lateral position was 12.1±19.8, 0.4±1.7, and 13.5± 20.1 events·h in N2, N3, and REM sleep, respectively. Thus, AHI was lower in lateral versus supine position in N2 and * Ioannis Koutsourelakis ikoutsourelakis@gmail.com