Airway Responses to Deep Inspiration in Asthma by Different Bronchial Challenge

2012 ◽  
Vol 18 (2) ◽  
pp. 75-80
Author(s):  
Chang-Wook Min ◽  
An-Soo Jang ◽  
Young-Seok Ji ◽  
Nam-Jun Cho ◽  
Kang-Hyug Choi ◽  
...  
2001 ◽  
Vol 91 (6) ◽  
pp. 2511-2516 ◽  
Author(s):  
S. J. Gunst ◽  
X. Shen ◽  
R. Ramchandani ◽  
R. S. Tepper

The effect of deep inspiration (DI) on airway responsiveness differs in asthmatic and normal human subjects. The mechanism for the effects of DI on airway responsiveness in vivo has not been identified. To elucidate potential mechanisms, we compared the effects of DI imposed before or during induced bronchoconstriction on the airway response to methacholine (MCh) in rabbits. The changes in airway resistance in response to intravenous MCh were continuously monitored. DI depressed the maximum response to MCh when imposed before or during the MCh challenge; however, the inhibitory effect of DI was greater when imposed during bronchoconstriction. Because immature rabbits have greater airway reactivity than mature rabbits, we compared the effects of DI on their airway responses. No differences were observed. Our results suggest that the mechanisms by which DI inhibits airway responsiveness do not depend on prior activation of airway smooth muscle (ASM). These results are consistent with the possibility that reorganization of the contractile apparatus caused by stretch of ASM during DI contributes to depression of the airway response.


1990 ◽  
Vol 3 (2) ◽  
pp. 89-92
Author(s):  
A.J. Dorward ◽  
B.M. Fisher ◽  
B.M. Frier ◽  
N.C. Thomson

1987 ◽  
Vol 72 (s16) ◽  
pp. 17P-17P
Author(s):  
B.M. Fisher ◽  
A.J. Dorward ◽  
N.C Thomson ◽  
B.M. Frier

2007 ◽  
Vol 102 (1) ◽  
pp. 269-275 ◽  
Author(s):  
Maurizio Meinero ◽  
Giuseppe Coletta ◽  
Luca Dutto ◽  
Manlio Milanese ◽  
Giorgio Nova ◽  
...  

The effects of supine posture on airway responses to inhaled methacholine and deep inspiration (DI) were studied in seven male volunteers. On a control day, subjects were in a seated position during both methacholine inhalation and lung function measurements. On a second occasion, the whole procedure was repeated with the subjects lying supine for the entire duration of the study. On a third occasion, methacholine was inhaled from the seated position and measurements were taken in a supine position. Finally, on a fourth occasion, methacholine was inhaled from the supine position and measurements were taken in the seated position. Going from sitting to supine position, the functional residual capacity decreased by ∼1 liter in all subjects. When lung function measurements (pulmonary resistance, dynamic elastance, residual volume, and maximal flows) were taken in supine position, the response to methacholine was greater than at control, and this was associated with a greater dyspnea and a faster recovery of dynamic elastance after DI. By contrast, when methacholine was inhaled in supine position but measurements were taken in sitting position, the response to methacholine was similar to control day. These findings document the potential of the decrease in the operational lung volumes in eliciting or sustaining airflow obstruction in nocturnal asthma. It is speculated that the exaggerated response to methacholine in the supine posture may variably contribute to airway smooth muscle adaptation to short length, airway wall edema, and faster airway renarrowing after a large inflation.


2017 ◽  
Vol 123 ◽  
pp. S450-S451
Author(s):  
F. Azoury ◽  
S. Achkar ◽  
N. Farah ◽  
D. Nasr ◽  
C. El Khoury ◽  
...  

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