Marica Pecis

Prevalence of normal tension glaucoma in obstructive sleep apnea syndrome patients.

PurposeTo explore the prevalence of normal tension glaucoma (NTG) among patients with obstructive sleep apnea syndrome (OSAS) and to examine OSAS as a risk factor of NTG. Patients and MethodsFifty-one consecutive white patients with OSAS were compared with 40 healthy subjects. All the study subjects underwent blood gas analysis, polysomnography, oxyhemoglobin saturation, and an ophthalmologic examination including visual field, visually evoked potential (VEP), and pattern electroretinography (PERG) and disc analysis with the Heidelberg Retina Tomograph II. ResultsThree of 51 OSAS patients (5.9%) had NTG. No patient in the control group had OSAS or NTG. The severity of OSAS correlated with intraocular pressure, the mean deviation of the visual field, the cup/disk ratio and the mean of the retinal nerve fiber layer thickness (P<0.01 to 0.001). Apnea hypopnea index and intraocular pressure were significantly greater in OSAS patients with abnormal VEP and PERG, compared to those with normal PERG and VEP. ConclusionsThe present study suggests that the prevalence of NTG in our OSAS patients is higher than expected in a white population of the same age and that OSAS may be an important risk factor for NTG. Our data underline the importance of taking an accurate sleep history from patients with NTG and referring patients with sleep disturbance for polysomnography.

Nasal resistances are useful in identifying children with severe obstructive sleep apnea before polysomnography

OBJECTIVE In this study, we would like to show that anterior rhinometry measurement of nasal resistance would be a simple and useful test to identify severe obstructive sleep apnea (OSA) in a population of children affected by adenotonsillar hypertrophy. METHODS Seventy-three consecutive children (44 males; mean age 5.4+/-1.2 years) with adenotonsillar hypertrophy, who complained sleep-disordered breathing, were studied. All the parents completed a questionnaire concerning the childrens sleeping habits and sleep complaints before consultation; each child underwent a general paediatric examination and an evaluation of craniofacial features and upper airway patency. In all 73 children polysomnography was performed and anterior rhinometry nasal patency was measured. RESULTS The diagnosis of OSA was confirmed in 44/73 patients (60%). Total nasal resistance showed a significant direct correlation with apnea hypopnea index, arousal index, snoring time, percentage of sleep time spent at SaO(2)<90% and a significant inverse correlation with total sleep time, sleep efficiency and the mean of SaO(2)% during sleep. Total nasal resistance was significantly related to snoring, mouth breathing and daytime sleepiness. The receiver operator characteristics (ROC) curve indicates that in the range of age of our sample a nasal resistance value of 0.59 Pa/cm(3)/s has a sensitivity of 91% and specificity of 96% for identifying the children with adenotonsillar hypertrophy affected by OSA. CONCLUSIONS Our study shows that in children with adenotonsillar hypertrophy nasal resistance seems to be risk factor for OSA. The anterior rhinometry appears as a useful tool in routine evaluation of sleep-disordered breathing in these patients.

Are COPD Patients with Nocturnal REM Sleep-Related Desaturations More Prone to Developing Chronic Respiratory Failure Requiring Long-Term Oxygen Therapy?

Background: Nocturnal oxygen desaturations (NOD), especially during REM sleep, have been described in patients with COPD. However, the role of NOD in the evolution of COPD to chronic respiratory failure has not been well studied. Objective: The aim of our study was to evaluate whether NOD is a risk factor for the development of chronic respiratory failure in COPD patients. Methods: We studied 34 consecutive COPD patients with a stable daytime PaO2 >60 mm Hg over a period of 42 months. We classified patients as desaturators (NOD) when episodic desaturations were found mainly during REM sleep, independently of baseline SaO2 values. Results: At enrolment 19 patients (55.8%) had NOD. Over the follow-up period, 10 patients (29.4%) were included in a long-term oxygen therapy (LTOT) programme (9 were desaturators). The LTOT was initiated a median time of 22 ± 6.8 months after enrolment. Patients who were subsequently prescribed LTOT had lower values of FEV1 at enrolment, with a higher degree of NOD and PaCO2. Stable respiratory failure developed earlier in patients with NOD: the two enrolment curves for LTOT differed significantly (log-rank test 2.56, p = 0.005). PaCO2, NOD and FEV1 were statistically significantly associated, both in univariate and multivariate Cox proportional hazards analyses, with an increased risk of entering a LTOT programme. Conclusions: We conclude that NOD may represent an independent risk factor for the development of chronic respiratory failure in COPD patients with daytime PaO2 >60 mm Hg. A larger study is needed to confirm the role of NOD in the natural history of COPD and subsequently to identify the most appropriate therapeutic approach.

Increased complexity of short-term heart rate variability in hyperthyroid patients during orthostatic challenge

Hyperthyroidism is a pathological condition characterized by an altered autonomic cardiovascular control, resulting in an increase of the sympathetic and a decrease of the parasympathetic modulation of heart rate variability. Recently, the entropy-based indices derived from short-term heart period variability have been proved to be helpful in evaluating the autonomic cardiovascular modulation. The aim of our study was to evaluate the autonomic cardiovascular modulation of hyperthyroid subjects at rest and during standing using spectral parameters and corrected conditional entropy indices derived from short-term heart period variability in 12 hyperthyroid (HYPTH) and 9 normal healthy (N) females. Mean heart period was significantly decreased by standing both in N and HYPTH and the LF power expressed in normalized units was increased. The respiratory rate was faster in the HYPTH group compared to N and complexity was significantly greater in HYPTH compared to N during standing. Results suggested an enhanced complexity of cardiovascular control in HYPTH, more evident in a condition of sympathetic activation. The increased complexity of the cardiovascular regulation is probably not completely due to autonomic control but also to other influences, such as metabolic effects of thyroid hormones impinging upon respiratory control mechanisms and, therefore, on cardiorespiratory coupling.

Acute particulate matter affects cardiovascular autonomic modulation and IFN-γ methylation in healthy volunteers

Aims: Air particulate matter (PM) is associated with increased cardiovascular morbidity and mortality. Altered autonomic functions play a key role in PM‐induced cardiovascular disease. However, previous studies have not address the impact of PM on sympathetic and parasympathetic control of heart function, independently, and using controlled conditions, i.e., increasing titration of PM of known composition, in absence of other potential confounding factors. To fill this gap, here we used symbolic analysis that is capable of detecting non‐mutual changes of the two autonomic branches, thus considering them as independent, and concentrations of PM as they could be measured at peak levels in Milan during a polluted winter day. Methods and results: In this randomized, cross‐over study, we enrolled 12 healthy subjects who underwent two random sessions: inhalation of filtered air mixture or inhalation of filtered air containing particulate mixture (PM 10, PM 2.5, PM 1.0 and PM 0.5 &mgr;m). ECG and respiration for autonomic analysis and blood sample for DNA Methylation were collected at baseline (T1), after air exposure (T2) and after 2 h (T3). Spectral and symbolic analysis of heart rate variability (HRV) were performed for autonomic control of cardiac function, while alterations in DNA methylation of candidate genes were used to index pro‐inflammatory modifications. In the PM expose group, autonomic analysis revealed a significant decrease of 2UV%, index of parasympathetic modulation (14% vs 9%, p = 0.0309), while DNA analysis showed a significant increase of interferon &ggr; (IFN‐ &ggr;) methylation, from T1 to T3. In a mixed model using T1, T2 and T3, fine and ultrafine PM fractions showed significant associations with IFN‐ &ggr; methylation and parasympathetic modulation. Conclusions: Our study shows, for the first time, that in healthy subjects, acute exposure to PM affects parasympathetic control of heart function and it increases methylation of a pro‐inflammatory gene (i.e. methylation of interferon &ggr;). Thus, our study suggests that, even in absence of other co‐factors and in otherwise healthy individuals, PM per se is sufficient to trigger parasympathetic dysautonomia, independently from changes in sympathetic control, and inflammation, in a dose‐dependent manner. HIGHLIGHTSIn healthy subjects, acute exposure to PM affects vagal autonomic control of the heart.PM exposure increases methylation of a pro‐inflammatory gene, i.e. methylation of interferon &ggr; (IFN‐ &ggr;).PM per se is able to trigger autonomic deregulation and inflammation in a dose‐dependent manner.

Autonomic Cardiovascular Control in Hyperthyroid Women during Sleep

Hyperthyroidism is characterized by hyperadrenergic symptoms (i.e., tachycardia, anxiety, and increased metabolic state). Although hyperthyroid patients often complain about an impairment of sleep, no data are available on sleep characteristics and autonomic cardiovascular control during sleep in these patients. We aimed to assess sleep qualitative indices and autonomic cardiovascular regulation during sleep in hyperthyroidism (Hyperthyr) and after treatment. Six subjects with a first diagnosis of Graves’ disease or hyperfunctioning nodule underwent a complete polysomnographic study (PSG) at the time of diagnosis and after the treatment, when they became euthyroid (Euthyr). ECG and respiratory signals were extracted and samples of consecutive 250–300 beats were analyzed using linear spectral and nonlinear entropy analysis of heart rate variability (HRV), during the different sleep stages. Heart rate was decreased and total power increased in Euthyr compared to Hyperthyr, both during wake and sleep; no changes of the sympathovagal balance were observed. Entropy analysis showed that regularity index was reduced in Euthyr compared to Hyperthyr, suggesting changes in the complexity of the cardiovascular control. Periodic leg movements (PLM) were reduced in Euthyr compared to Hyperthyr. In conclusion, hyperthyroidism seems to be associated with an increased sleep fragmentation, due to PLM and an altered cardiac autonomic control.

Effective nocturnal oxygen therapy increases circulating level of tumor necrosis factor-alpha in heart failure.

Objectives Tumor necrosis factor (TNF)-α is elevated in chronic heart failure (CHF). The cause of this increase is not well known. Several hypotheses have been investigated. Previous experimental and clinical studies detected changes in TNF circulating levels related to arterial oxygen (O2) saturation. The aim of the present study was to evaluate whether standard O2 hospital therapy affects plasma concentration of TNF-α in stable CHF patients. Methods A total of 18 patients (New York Heart Association class II and III) were enrolled and randomly assigned to two different orders of treatment: nine patients underwent a first night of O2 applied by nasal prongs and a second night of air delivered by nasal prongs, whereas the other nine patients were assigned to the contrary order of treatments (i.e. first night with air and second night with O2) in a crossover design. Results Ten patients out of 18 had O2 saturation above 95% for at least 360 min. In these ten patients, the TNF-α plasma level increased after O2 compared to the basal condition (delta 5.47 ± 1.72 pg/ml; P < 0.05) whereas, in the same patients, the TNF-α plasma level did not change after the night with air (delta –0.05 ± 3.03 pg/ml). A linear positive correlation (r = 0.62, P < 0.01) between minutes of O2 saturation above 95% and TNF-α circulating differences from basal to post-O2 therapy was found. Conclusions Effective nocturnal hospital O2 therapy affects TNF-α plasma levels and the increase of TNF-α appears to be linearly related to the time of blood O2 saturation above 95%.