Breathing Conditions (breathing + condition)

Distribution by Scientific Domains


Selected Abstracts


The effects of paced breathing on respiratory resistance are minimal in healthy individuals

PSYCHOPHYSIOLOGY, Issue 5 2009
Thomas Ritz
Abstract Paced breathing has been criticized for its presumed influences on autonomic and respiratory regulation, among that on respiratory resistance. It has been speculated that excessive pulmonary stretch receptor activation through high tidal volume (VT) would be the mechanism underlying such influences. However, the idea of airway dilation by paced breathing has remained untested. We analyzed inspiratory and expiratory resistance measured by forced oscillations in 26 healthy participants during baseline and two paced breathing conditions, regular pacing with instructions to alter rate only and pacing with additional instructions to alter volume randomly throughout the task. In each condition, four 3-min paced breathing trials at 8, 10.5, 13, and 18 breaths/min were administered. Despite pronounced changes in respiration rates and VT across pacing trials, neither inspiratory nor expiratory resistance were changed significantly under the regular paced breathing condition. A small reduction in resistance was only observed under conditions of variable volume at 18 breaths/min. Thus, regular paced breathing at different speeds across a range of naturally occurring breathing frequencies has only minimal effects on resistance of the airway passages. [source]


Delivery of nebulized budesonide is affected by nebulizer type and breathing pattern

JOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 6 2005
C. O'Callaghan
The aim of this study was to determine the output in-vitro of budesonide from two different nebulizers under simulated breathing conditions. The BimboNeb and Nebula nebulizers were used to nebulize 2 mL of budesonide (500 ,g) suspension. Particle size was determined by inertial impaction after a 5-min nebulization. Total outputs of the drug from both nebulizers were measured using a sinus flow pump to create simulated breathing conditions. Paediatric and adult breathing patterns were used, with drug output measured after 5 and 10 min nebulization. The mass median aerodynamic diameter of budesonide using the BimboNeb (4.5 ,m) was significantly greater than that from the Nebula (3.4 ,m) (P < 0.01). With the simulated adult breathing pattern, the total drug output after 5 min with the BimboNeb (61.5 ,g) was twice that from the Nebula (30.7 ,g). For the paediatric breathing pattern, total outputs were very similar for both nebulizers. In all cases, nebulizing for 10 min produced greater drug outputs compared with those after 5 min, particularly for the paediatric breathing pattern. The amount of aerosolized drug available for inhalation needs to be assessed for each nebuliser used and the effect of the patient's breathing pattern should also be taken into account. [source]


The output of flunisolide from different nebulisers

JOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 4 2002
Chris O'Callaghan
The objective of this study was to determine the output, in-vitro, solution of a concentrated solution of flunisolide from two different nebulisers under simulated breathing conditions. The BimboNeb and Nebula nebulisers were used to nebulise 2.6 mL of flunisolide solution (600 ,g). Particle size was determined by inertial impaction and the total output of drug from the nebulisers under simulated breathing conditions was measured using a sinus flow pump. Two different breathing patterns were used, simulating nebuliser use by a child and an adult. The mass median aerodynamic diameter of flunisolide particles from the BimboNeb and Nebula were both 3.9 ,m. With the simulated paediatric breathing pattern, both nebulisers delivered similar amounts of flunisolide (56.4 ,g (s.d. 1.4,g) and 56.1 ,g (5 ,g) over 5 min from the BimboNeb and Nebula, respectively). With the adult breathing pattern, flunisolide delivery from the BimboNeb was increased to 88.9 ,g (3.3 ,g), but delivery from the Nebula was only slightly increased to 64.6 ,g (1.4 ,g). With both nebulisers, little drug was released after 5 min of nebulisation. Both nebulisers delivered 9,15 % of the nominal dose of flunisolide to the breathing simulator, a similar percentage to previous studies with budesonide and more than previous studies with beclometasone. Drug delivery from the BimboNeb, but not the Nebula, was affected by the simulated breathing pattern. This study suggests that drug delivery from nebulisers is dependent upon the interaction between the nebuliser, the drug and the patient. [source]


Retrospective cine 3He ventilation imaging under spontaneous breathing conditions: a non-invasive protocol for small-animal lung function imaging

NMR IN BIOMEDICINE, Issue 2 2007
Vasile Stupar
Abstract A non-invasive and free-breathing hyperpolarized (HP) 3He imaging protocol for small animals was implemented and validated on rats for lung function imaging. Animals were allowed to breathe a mixture of air and 3He from a mask and a gas reservoir fitted to their heads. Radial imaging sequences were used, and MRI signal intensity changes were monitored for retrospective cine image reconstruction. The ventilation cycle of the animals was imaged with a 100,ms temporal resolution. The sliding window imaging technique was applied to reconstruct 5,ms time-shifted image series covering the complete breathing cycle. Image series were processed to extract quantitative ventilation parameters such as the gas arrival time. The reproducibility and the non-invasiveness of this ventilation imaging protocol were evaluated by multiple acquisitions on the same animals. Copyright 2006 John Wiley & Sons, Ltd. [source]


The effects of paced breathing on respiratory resistance are minimal in healthy individuals

PSYCHOPHYSIOLOGY, Issue 5 2009
Thomas Ritz
Abstract Paced breathing has been criticized for its presumed influences on autonomic and respiratory regulation, among that on respiratory resistance. It has been speculated that excessive pulmonary stretch receptor activation through high tidal volume (VT) would be the mechanism underlying such influences. However, the idea of airway dilation by paced breathing has remained untested. We analyzed inspiratory and expiratory resistance measured by forced oscillations in 26 healthy participants during baseline and two paced breathing conditions, regular pacing with instructions to alter rate only and pacing with additional instructions to alter volume randomly throughout the task. In each condition, four 3-min paced breathing trials at 8, 10.5, 13, and 18 breaths/min were administered. Despite pronounced changes in respiration rates and VT across pacing trials, neither inspiratory nor expiratory resistance were changed significantly under the regular paced breathing condition. A small reduction in resistance was only observed under conditions of variable volume at 18 breaths/min. Thus, regular paced breathing at different speeds across a range of naturally occurring breathing frequencies has only minimal effects on resistance of the airway passages. [source]