The performance of the Pneupac Ventipac portable gas-powered ventilator was evaluated in two stages. The accuracy of delivery of the ventilator was assessed using a mechanical lung model at different combinations of compliance and airway resistance to simulate normal and diseased lungs. The performance of the ventilator was then assessed in 20 anaesthetized patients. The tidal volume delivered ...

This study was designed to determine whether resistance to the airway effects of the beta-agonist, salbutamol, would develop in three groups of subjects while taking large doses of inhaled salbutamol. Six normal non-atopic, six atopic non-asthmatic, and eight atopic asthmatic subjects were studied by an identical technique. The development of resistance was assessed from salbutamol dose-respons...

To determine the relationship between upper airway muscle activity and upper airway resistance in nonsnoring and snoring young adults, 17 subjects were studied during sleep. Genioglossus and alae nasi electromyogram activity were recorded. Inspiratory and expiratory supraglottic resistance (Rinsp and Rexp, respectively) were measured at peak flow, and the coefficients of resistance (Kinsp and K...

Hyperpnoea of canine peripheral airways with dry air results in airway obstruction, mucosal damage, and inflammation. The purpose of this study was to evaluate the effect of repeated dry air challenge (DAC) on airway obstruction, reactivity and the development of airway inflammation in dogs. Canine peripheral airways received DAC (delivered under general anaesthesia through a bronchoscope) ever...

We report a forced oscillatory technique for noninvasively measuring respiratory transfer impedance (Ztr) between 8 and 384 Hz in guinea pigs. This technique uses a device consisting of two chambers: one surrounding the animal's head that is used as a plethysmograph to measured flow through the airway opening and the other that surrounds the animal's body and is used to apply pressure oscillati...

Nicotinic agonists, including 1,1-dimethyl-4-phenylpiperazinium (DMPP), have anti-inflammatory properties and in some instances smooth muscle relaxing effects. Since inflammation and airway smooth muscle contraction are two major components of asthma, the present authors investigated the effects of DMPP on airway inflammation and airway resistance in a mouse model of asthma. Mice were sensitise...

background: establishment of a patent airway and preserving spontaneous ventilation is a necessity in predicted difficult airway. airway regional blocks are commonly used in predicted difficult airway but the known limitations of these techniques propose the need to suggest alternative methods. this study compares subcutaneous dissociative conscious sedation (sdcs); a recently reported method o...

OBJECTIVE To evaluate the effect of selective electrical stimulation of the tensor veli palatini muscle on upper airway patency. METHODS Pressure-flow relationships were evaluated, in a feline isolated upper airway preparation, to determine the role of the soft palate musculature on airflow dynamics. The tensor veli palatini muscles were selectively stimulated while monitoring upper airway co...

THE RESPIRATORY SYSTEM is composed of a conducting part and a respiratory part. The conducting airways, i.e., the trachea, bronchi, and bronchioles, differ in architecture. Both trachea and bronchi are surrounded by rings of hyaline cartilage for support, whereas the bronchiolar wall does not contain any cartilage and therefore tends to collapse in response to changes in intrapleural or airway ...

We do not yet have a good quantitative understanding of how the force-velocity properties of airway smooth muscle interact with the opposing loads of parenchymal tethering and airway wall stiffness to produce the dynamics of bronchoconstriction. We therefore developed a two-dimensional computational model of a dynamically narrowing airway embedded in uniformly elastic lung parenchyma and compar...