The diameter of the inferior vena cava (IVC) measured with echocardiography is clinically used as a parameter to estimate right atrial pressure, which reflects dehydration or overhydration. Because elderly patients fall easily into dehydration, normal values for IVC diameters in elderly patients may be helpful for geriatric medicine. However, normal values of IVC diameter in relation to age hav...

The upper airway muscles play an important role in maintaining upper airway collapsibility, and the incidence of sleep-disordered breathing increases with age. We hypothesize that the increase in airway collapsibility with increasing age can be linked to changes in upper airway muscle mechanics and structure. Eight young (Y: 6 mo) and eight old (O: 30 mo) Fischer 344 rats were anesthetized and ...

PURPOSE To develop and demonstrate a real-time MRI method for assessing upper airway collapsibility in sleep apnea. MATERIALS AND METHODS Data were acquired on a clinical 3 Tesla scanner using a radial CAIPIRIHNA sequence with modified golden angle view ordering and reconstructed using parallel imaging and compressed sensing with temporal finite difference sparsity constraint. Segmented airwa...

Physiologic, metabolic, and histochemical characteristics of one upper airway (UA) dilator muscle (musculus uvulae; MU) differ between sleep apnea hypopnea syndrome (SAHS) and nonapneic snorers. We hypothesized that these differences in MU characteristics could result from the cumulative effects of the diurnal and nocturnal intermittent contractions of UA muscles in order to compensate for a pe...

RATIONALE AND OBJECTIVES To evaluate the correlations of tracheal volume and collapsibility on inspiratory and end-expiratory computed tomography (CT) with lung volume and with lung function in smokers. MATERIALS AND METHODS The institutional review board approved this study at each institution. 85 smokers (mean age 68, range 45-87 years; 40 females and 45 males) underwent pulmonary function ...

BACKGROUND Obstructive sleep apnea is strongly associated with obesity, particularly abdominal obesity common in centrally obese males. Previous studies have demonstrated that intra-abdominal pressure (IAP) is increased in morbid obesity, and tracheal traction forces may influence pharyngeal airway collapsibility. This study aimed to investigate that whether IAP plays a role in the mechanism of...

BACKGROUND The clinical criteria to assess hydration status are not always reliable. Hence, the development of techniques to estimate more accurately post-dialysis dry weight (DW) remains a major challenge. The present study evaluates the value of the inferior vena cava (IVC) diameter, plasma concentration of atrial natriuretic peptide (ANP), and plasma renin activity (PRA) in determining the D...

Obstructive sleep apnea patients experience recurrent upper airway (UA) collapse due to decreases in the UA dilator muscle activity during sleep. In contrast, activation of UA dilators reduces pharyngeal critical pressure (Pcrit, an index of pharyngeal collapsibility), suggesting an inverse relationship between pharyngeal collapsibility and dilator activity. Since most UA muscles display phasic...