Editorial: Obstructive sleep apnea syndrome (OSAS). What's new?

This Research Topic entitled “Obstructive sleep apnea syndrome (OSAS). What's new?”, involving authors from different specializations and numerous countries, confirms that OSAS is a hot topic. OSA syndrome is an airway obstruction (i.e. complete or partial) with numerous etiologies (1–4). Different papers have demonstrated that the prevalence of OSAS is 2–4% in men and 1–2% in women of average age. The reference tools for OSAS diagnosis are clinical polysomnography or nocturnal portable multi-channel monitoring. Frequently, continuous positive airway pressure (CPAP) therapy is the first treatment for a patient (5, 6). Long-term CPAP treatment may present limited compliance, and there is no unanimous opinion on other alternative treatments for OSAS in literature on the subject. This special issue discusses several of these “unmet needs”

Low arousal threshold: a common pathophysiological trait in patients with obstructive sleep apnea syndrome and asthma

Introduction: Obstructive sleep apnea syndrome (OSAS) and asthma are two diseases with a high epidemiological impact that may often coexist. Both diseases have underlying pathogenic mechanisms (chronic inflammation, genetic predisposition, etc.); it is still unclear whether or not their coexistence is due to a specific pathophysiological factor. In the literature, the pathogenesis of OSAS has four pathophysiological traits: one or more anatomical predisposing factors, a low arousal threshold (low AT), high loop gain, and poor muscle responsiveness. In this study, we hypothesized that a low AT is a common pathophysiological factor in OSAS and asthma. Methods: A retrospective study of patients attending the Pulmonology Unit of the University Hospital of Trieste was carried out. Low AT was predicted on the bases of the following polysomnography features, as previously shown by Edwards et al.: an AHI of < 30 events/h, a nadir SpO2 of > 82.5%, and a hypopnea fraction of total respiratory events of > 58.3%. Results: Thirty-five patients with asthma and OSAS and 36 with OSAS alone were included in the study. Low AT was present in 71% of patients affected by asthma and OSAS (25 patients out of 35) versus 31% (11 patients out of 36) of patients affected by OSAS alone with a statistically significant difference (p = 0.002) between the two groups. Stratifying for BMI and OSAS severity, the difference between groups remained statistically significant. Conclusions: This is the first study to describe specific polysomnographic characteristics of patients affected by asthma and OSAS. A low AT may well be the pathophysiological factor common to the two diseases. If confirmed by other studies, this finding could lead to the presence of asthma and OSAS in the same individual being considered a syndrome with a common pathophysiological factor

Prolonged higher dose methylprednisolone vs. conventional dexamethasone in COVID-19 pneumonia: a randomised controlled trial (MEDEAS)

Dysregulated systemic inflammation is the primary driver of mortality in severe COVID-19 pneumonia. Current guidelines favor a 7-10-day course of any glucocorticoid equivalent to dexamethasone 6 mg·day-1. A comparative RCT with a higher dose and a longer duration of intervention was lacking

Management of patients with neuromuscular disorders and acute respiratory failure

Acute respiratory failure (ARF) is a common cause of morbidity and mortality in most advanced neuromuscular disorders (NMD). Deterioration of lung function during NMD may have different severity and time course. During slowly progressive neuromuscular disease an acute event can precipitate the respiratory failure, while rapidly progressive NMD may present as ARF at the onset of the disease. During ARF a patient with NMD may be affected by inspiratory muscles weakness responsible for decreased ventilation, expiratory muscles weakness responsible for altered coughing effectiveness, and bulbar involvement responsible for altered swallowing and airway protection. Neuromuscular disorders may also affect central control of breathing, sleep disorder, bones and joints deformities with consequent ventilatory dysfunction. Usually ARF in NMD is prompted by precipitating factors such as upper airways infections, pneumonia, atelectasis etc. It is important to distinguish respiratory failure due to an acute event or to a rapidly progression of underlying conditions to properly allocate the patient in the more appropriate setting of care. Generally, excessive invasiveness of care must be avoided, and a pro-active early rehabilitation program may help early recovery and minimize complications. Mechanical non invasive positive pressure ventilation(NIPPV) combined with mechanically assisted coughing (MAC) has been established as the standard treatment of severe ARF in NMD. Superiority of NIPPV vs invasive mechanical ventilation (MV) was showed in term of lower mortality, treatment failure, duration of ICU in several studies. Home mechanical noninvasive ventilation and MAC may result dramatic reduction in the need for hospitalization and a prolongation of life expectancy of these patients. To avoid the progression of respiratory failure an early identification of respiratory deterioration is needed, as such as prevention of acute episodes. So, especially in the progressive diseases, is very important to monitor respiratory status with periodic lung function tests. Any respiratory tract infection in neuromuscular disease could trigger acute respiratory failure so it is mandatory take any aggressive measures to prevent and treat this complication. Some of principal preventive measures include vaccination against Pneumococcus Pn. and influenza virus, early antibiotic treatment when bacterial infection is suspected, chest physiotherapy for removal airway secretions or mechanical assisted maneuvers to increase cough efficiency. In conclusion, a proactive, preventive approach is the key for optimal management acute respiratory problems in neuromuscular disorders

The plasminogen system and transforming growth factor-β in subjects with obstructive sleep pnea syndrome: effects of CPAP treatment

Obstructive sleep apnea syndrome (OSAS) has emerged as a risk factor for cardiovascular disease. A prothrombotic state may affect coagulation and participate in the atherosclerotic process in subjects with OSAS. These alterations in coagulation seem to involve the plasminogen activation system. We evaluated the imbalances of the plasminogen activation system related to OSAS, and we assessed the effects of CPAP on the plasminogen activation system

Laser Speckle Contrast Analysis: Functional Evaluation of Microvascular Damage in Connective Tissue Diseases. Is There Evidence of Correlations With Organ Involvement, Such as Pulmonary Damage?

Laser speckle contrast analysis (LASCA) is a non-contact technique able to quantify peripheral blood perfusion (PBP) over large skin areas. LASCA has been used to study hand PBP in several clinical conditions. These include systemic sclerosis (SSc) and systemic lupus erythematosus (SLE) and LASCA showed that PBP was significantly lower in these conditions than in healthy subjects (HS). Moreover, it has been demonstrated that LASCA is a safe technique also able to monitor digital ulcer perfusion and their evolution in SSc patients, during systemic and local treatment. The use of LASCA, coupled with reactivity tests is commonplace in the field of microvascular function research. Post-occlusive hyperemia reactivity (POHR) and local thermal hyperemia, associated with laser techniques are reliable tests in the evaluation of perfusion in SSc patients. Other studies used laser speckled techniques, together with acetylcholine and sodium nitroprusside iontophoresis, as specific tests of endothelium function. In conclusion, LASCA is a safe, non-contact reliable instrument for the quantification of PBP at skin level and can also be associated with reactivity tests to monitor disease progression and response to treatment in different connective tissue diseases

Low Arousal Threshold Estimation Predicts Failure of Mandibular Advancement Devices in Obstructive Sleep Apnea Syndrome

Introduction: The treatment of choice for obstructive sleep apnea syndrome (OSAS) is continuous positive airway pressure (CPAP). However, CPAP is usually poorly tolerated and mandibular advancement devices (MADs) are an alternative innovative therapeutic approach. Uncertainty still remains as to the most suitable candidates for MAD. Herein, it is hypothesized that the presence of low arousal threshold (low ArTH) could be predictive of MAD treatment failure. Methods: A total of 32 consecutive patients, with OSAS of any severity, who preferred an alternate therapy to CPAP, were treated with a tailored MAD aimed at obtaining 50% of their maximal mandibular advancement. Treatment response after 6 months of therapy was defined as AHI < 5 events per hour or a reduction of AHI ≥ 50% from baseline. Low ArTH was predicted based on the following polysomnography features, as previously shown by Edwards et al.: an AHI of 82.5% and a hypopnea fraction of total respiratory events of >58.3%. Results: There were 25 (78.1%) responders (p-value < 0.01) at 6 months. Thirteen patients (40.6%) in the non-severe group reached AHI lower than 5 events per hour. MAD treatment significantly reduced the median AHI in all patients from a median value of 22.5 to 6.5 (74.7% of reduction, p-value < 0.001). The mandibular advancement device reduced AHI, whatever the disease severity. A significant higher reduction of Delta AHI, after 6 months of treatment, was found for patients without low ArTH. Conclusions: Low ArTH at baseline was associated with a poorer response to MAD treatment and a lower AHI reduction at 6 months. A non-invasive assessment of Low ArTH can be performed through the Edwards’ score, which could help to identify an endotype with a lower predicted response to oral appliances in a clinical setting