Increased oral nitric oxide in obstructive sleep apnoea

SummaryBackgroundHypoxia and snoring-related mechanical trauma contribute to airway inflammation in obstructive sleep apnoea (OSA). Increased exhaled nitric oxide (FENO), an airway inflammation marker, has been reported in OSA patients. We propose the measure of NO in the oral cavity (oNO) as marker of oropharyngeal inflammation in OSA.MethodsWe compared oNO and FENO of 39 OSA patients with those of 26 mild asthmatics (ASTHMA), 15 patients with chronic rhinitis or rhinosinusitis (CRS) and 24 healthy subjects. A special device was used for oNO measurement. Apnoea/hypopnoea index (AHI), oxygen desaturation index, mean and nadir SaO2 were calculated from the polysomnography.ResultsoNO was significantly increased in OSA (104.2 95%CI 80.2–135.5ppb) as compared to ASTHMA (71.9 95%CI 56.3–91.9ppb; p=0.015), CRS (54.4 95%CI 40.2–73.7ppb; p=0.009) and healthy subjects (63.6 95%CI 59–73ppb; p<0.001). oNO was directly related to AHI (r=0.466, p=0.003) and to minutes slept with SaO2 <90% (r=0.471, p=0.011) and it was inversely related to nadirSaO2 (r=−0.393, p=0.018). FENO was highest in asthmatics (40.3 95%CI 32.5–50.1ppb) and only slightly elevated in OSA (23.1 95%CI 19,8–28.3ppb) and CRS (22.8 95%CI 16.8–32.5ppb).ConclusionsThe finding that oral NO is increased in OSA and is related to upper airway obstructive episodes and to hypoxemia severity, strengthens the clinical and pathogenic role of oral inflammation in OSA

Manipulating the flow over a circular cylinder with control rods

The flow past a circular cylinder with control rods at moderate values of Reynolds number is experimentally investigated in this work. The flow topology depends on many parameters, such as Reynolds number, the ratio between the diameter of the cylinders, number and position of the rods. Preliminary experiments on the sensitivity of fluid forces have shown that the rod's position is the most relevant among all the parameters tested. The hydrodynamic forces suffer the greatest variation when the rod is placed close to the shear layers or the cylinder's surface. Detailed investigation of the wake with one-rod using fixed values of Re=20,000, and d/D=0.1 has shown that the wake developed three distinct states, depending on the rod's angular position. State I is characterised by two distinct vortex streets, downstream of the cylinder and rod, respectively. State II is characterised by a strong jet between the cylinder and the rod and a late separation due to Coanda effect. And in State III the rod acts in the recirculation region, with a relatively lower influence in the flow compared to the other states. In addition, a bi-stable case was observed between the states II and III, with no clear switching frequency between the states and very sensitive to the rod's position. Adding a second and symmetrical rod to the system turns the mean flow symmetric for States I and III, whereas State II shows an asymmetric mean wake due to a bi-stable behaviour induced by the imbalance of the jets in the near wake. A transitional case was observed between State I and II, with a type of separation not observed for one-rod cases, which showed a reduction of 90% in the fluctuating lift force. The position of the separation point varied significantly for States I and II compared to that of a bare cylinder. It prompted a significant impact on the hydrodynamic forces acting on the cylinder. The greatest reductions of the mean drag force were observed for State II cases with two-rod: 20\% for the combined system and 30\% for the main cylinder, both with respect to the bare cylinder case.Open Acces

Cognitive-Behavioral and Pharmacological Treatments for Insomnia: A Combined Approach

Insomnia is the most prevalent sleep disorder (10-40%). It is defined as the subjective perception of difficulty with sleep initiation, duration, consolidation, or quality that occurs despite adequate opportunity for sleep and that results in some form of daytime impairment. Among the typical symptoms, there are fatigue, decreased mood or irritability, general malaise, and cognitive impairment. According to the International Classification of Sleep Disorders 3rd edition, ICSD-3, it has been defined as chronic (lasting more than three months) or short-term insomnia (less than three months).In clinical practice, the usual therapeutic approach is pharmacological (benzodiazepines, z drugs, slow wave sleep enhancers), even if the American Academy of Sleep Medicine (AASM), the American College of Physicians (ACP), and the European Sleep Research Society (ESRS) guidelines suggest that the first clinical choice should be non-pharmacological (cognitive behavioral therapy). A combined (non-pharmacological and pharmacological)approach could be considered in poor responders to manage drug dependence and to increase compliance to treatment and patients' quality of life