Tracheal pressure, central airflow, and alveolar capsule pressures in cardiac lobes were measured in open-chest dogs during 0.1- to 20-Hz pseudorandom forced oscillations applied at the airway opening. In the interval 0.1-4.15 Hz, the input impedance data were fitted by four-parameter models including frequency-independent airway resistance and inertance and tissue parts featuring a marked nega...

STUDY OBJECTIVES Nasal prongs (NPs), when used to assess nasal flow, can result in dramatic increases in nasal airflow resistance (NR). The aim of this study was to investigate whether the NP-induced increases in NR could be corrected by the simultaneous use of an internal nasal dilator (ND). DESIGN NR was estimated by posterior rhinomanometry, in the basal state (NRb), and while breathing wi...

We examined whether topical upper airway anesthesia leads to a reduction in genioglossal (GG) electromyogram (EMG) in patients with obstructive sleep apnea (OSA). Airway mechanics were also evaluated. In 13 patients with OSA, we monitored GG EMG during tidal breathing and during the application of pulses of negative airway pressure (-10 to -12 cmH(2)O). Airflow resistance and airway collapsibil...

The electromyographic (EMG) activity of human upper airway muscles, particularly the genioglossus, has been widely measured, but the relationship between EMG activity and physical movement of the airway muscles remains unclear. We aimed to measure the motion of the soft tissues surrounding the airway during normal and loaded inspiration on the basis of the hypothesis that this motion would be a...

The upper airway resistance syndrome (UARS) is a recently described form of sleep-disordered breathing in which repetitive increases in resistance to airflow within the upper airway lead to brief arousals and daytime somnolence. This review will first describe the chronological progression of our understanding of UARS within the broader context of sleep-disordered breathing. The primary symptom...

The effects on airflow resistance of an inhaled H1 receptor antagonist, clemastine, and an H2 receptor antagonist, cimetidine, have been investigated in normal and asthmatic subjects. No significant changes in specific conductance (sGaw) were seen in six normal subjects. In eight asthmatic subjects a significant increase in forced expiratory volume in one second (FEV1) occurred at 60 min (< 0.0...

UNLABELLED Mandibular cross-sectional deficiency is a dentofacial defect in connection with the narrowing of the mandibular arch width. This abnormality is a significant etiopathogenic factor and it is often associated with nasal breathing difficulties. This atresia may be treated through Rapid Maxillary Expansion or Surgically Assisted Rapid Maxillary Expansion, depending on the patient's age....

Research reports on pulmonary function measurements often mention caffeine abstinence as a condition for testing subjects. Yet, the effects of caffeine on respiration are not well documented. This study was intended to investigate the physiological effects of caffeine on respiratory resistance measurements and the necessity of caffeine avoidance in such testing. Thirty-one subjects were adminis...