Changes In Airway Patency Research Articles

Changes in airway patency and sleep-breathing in healthy skeletal Class II children undergoing functional activator therapy.

Several studies agree that an abnormal maxilla-mandible relationship correlates better as an Obstructive Sleep Apnea (OSA) predictor, rather than obesity. One of the orthodontic therapies recommended for this kind of craniofacial deformity is to advance the mandible forward with an orthodontic activator, therefore, the aim of this study is to determine if healthy children that use this appliance experience a widening of the upper airway as well as an improvement in their sleep-breathing patterns. 39 healthy children, 20 for activator group (10 boys and 10 girls, 4 mean age 10.9 + 0.9; BMI 16.2 + 1.4), 19 for control group (13 boys and 6 girls, mean age 5 9.8 + 1.4; BMI 17.6 + 2.1) participated in this study. They were required to submit 2 lateral cephalometric radiographs both at initial and final stages of evaluation, and finally three at- home sleep-breathing monitoring results for the activator group and one for the control group. After radiographic evaluation, it was found that children in the activator group experienced an increase in all measured variables. After evaluation with the sleep monitor, an improvement of sleep-breathing was found in children from the activator group (p<0.05). The activator not only provides a harmonious occlusion and proper development of the mandible, but it also helps improve the quality of sleep-breathing through widening of the upper airway and reducing the number of disordered breathing events in children that undergo this therapy.

0534 Balanced Co-activation of Protrudors and Rectractors is Required to Prevent Pharyngeal Obstruction During Sleep

Obstructive sleep apnea (OSA) is characterized by recurrent upper airway obstruction caused by a loss of upper airway muscle tone during sleep. Reductions in Genioglossus (GG) muscle tone, the main upper airway (UA) dilator, during sleep is thought to play a critical role in the pathogenesis of UA obstruction. Nevertheless, recent evidence suggests that lingual retractors also stabilize UA patency during sleep, leading us to hypothesize that co-activating lingual muscles can augment responses in UA patency during sleep 14 apneic patients implanted with a multi-channel hypoglossal nerve stimulating system (Imthera aura 6000) underwent mid-sagittal ultrasound tongue imaging during wakefulness. Changes in tongue shape and position were characterized by measuring its vertical height and the polar dimensions between the tongue surface and genioglossus origin in the mandible (mental spine). Changes in airway patency were characterized by comparing airflow responses between stimulated and adjacent unstimulated breaths during NREM sleep. Two distinct morphologic responses to stimulation were observed. Anterior tongue base and hyoid bone movement (5.3 ± 0.2 to 4.2 ± 0.5 cm) with concomitant increases in tongue height (4.7 ± 0.4 to 5.3 ± 0.7 cm) resulting in only modest changes in airway patency. In contrast, when stimulation generated forward movement (5.7 ± 0.3 to 4.5 ± 0.7 cm) without any increase in height (4.6 ± 0.5 to 4.6 ± 0.9 cm), marked increases in airway patency were observed. Lingual muscles that protrude the tongue while preserving tongue shape and prevent the tongue from bulging upward were associated with greater increases in pharyngeal patency during sleep. These morphologic differences suggest that co-stimulating lingual muscles stiffen the tongue, and prevent it from prolapsing into the pharynx during sleep. Our findings further suggest that dilating and stiffening actions of lingual protrudors and retractors can maintain UA patency during sleep. Imthera Medical AHA: 16post31000017.

Clinical and functional responses to salbutamol inhaled via different devices in asthmatic patients with induced bronchoconstriction

This study aimed at evaluating changes in airway patency, lung volumes and perception of breathing discomfort intensity following salbutamol administration via the Diskus dry-powder inhaler (DPI) or a pressurized metered-dose inhaler with the Volumatic valved holding chamber (pMDI + Volumatic) in asthmatic patients with methacholine-induced bronchoconstriction. On six different study days, 18 patients inhaled methacholine until forced expiratory volume in 1 s (FEV(1)) decreased by approximately 35% of baseline. Following placebo, 200 and 400 microg of salbutamol through the pMDI + Volumatic or the Diskus, changes in FEV(1), volume-adjusted mean forced expiratory flow from 25 to 75% of the forced vital capacity (isoFEF(25-75)), lung volumes and breathing discomfort intensity, assessed by visual analogue scale (VAS) score, were repeatedly measured over a 60-min observation period. Induced bronchoconstriction was accompanied by obvious reductions in lung volumes and increases in VAS score. After salbutamol administration, FEV(1) and VAS score changes were similar in all experimental conditions. However, following 400 microg salbutamol via pMDI + Volumatic, isoFEF(25-75) values increased up to 4.48 l s(-1) (95% confidence interval 4.06, 4.90), a significantly (P < 0.01) higher value than those attained in all other experimental conditions. Independently of the salbutamol dose, lung volumes rose to significantly (P < 0.01) higher levels in pMDI + Volumatic than in Diskus trials. The low salbutamol dose via the pMDI + Volumatic and the high dose via the DPI increased isoFEF(25-75) and lung volumes to similar extents. Salbutamol via the pMDI + Volumatic provides greater isoFEF(25-75) and lung volume increases in asthmatic patients with induced bronchoconstriction; salbutamol-induced changes in VAS scores poorly reflect those in small airway patency. The lack of differences in FEV(1) increases observed after 200 and 400 microg salbutamol may reflect attainment of the flat portion of the dose-response curve using either device.

Monitoring Nasal and Oral Airway Patency

The hypothesis that upper airway breathing behaviors generally follow the rules of a physiologic regulating system implies the existence of sensors that monitor the airway environment. The purpose of this study was to assess the sensitivity of the monitoring system to sudden changes in airway patency in healthy, adult subjects. An instrument capable of changing airway dimensions in about 10 ms was used to assess psychophysical recognition and physiologic responses to sudden changes in airway size. Our results indicate that psychophysical recognition of change in patency occurred at a mean constriction area of 0.31 cm2. These findings suggest that recognition of change in airway size occurs well before the airway becomes flow-limiting or severely obstructed.

Monitoring nasal and oral airway patency.

The hypothesis that upper airway breathing behaviors generally follow the rules of a physiologic regulating system implies the existence of sensors that monitor the airway environment. The purpose of this study was to assess the sensitivity of the monitoring system to sudden changes in airway patency in healthy, adult subjects. An instrument capable of changing airway dimensions in about 10 ms was used to assess psychophysical recognition and physiologic responses to sudden changes in airway size. Our results indicate that psychophysical recognition of change in patency occurred at a mean constriction area of 0.31 cm2. These findings suggest that recognition of change in airway size occurs well before the airway becomes flow-limiting or severely obstructed.