The goal of this Clinical Investigator Development Award is to further development and training of an independent academic investigator in anesthesiology and physiology. The research will emphasize a new technology that permits three-dimensional reconstruction of the pulmonary airways and vessels in vivo. It has two primary objectives, the first to establish the local responsiveness of conducting airways to various stimuli, the second to determine the extent of interaction between the pulmonary vasculature and conducting airways. Specific research aims will first be directed toward the testing of the response of airways to a variety of interventions relevant to standard airways function tests used to assess lung disease. We will test the mechanism and extent of regional airway response heterogeneity in different size airways in vivo to bronchoconstrictors and bronchodilators that have been reported to differentially constrict portions the airway tree or work through different pharmacologic pathways. I will also be able to evaluate the effect of the pulmonary vasculature on the airway tree. Preliminary data have shown that even relatively large conducting airways can be partially obstructed when the pulmonary vasculature pressure is increased. We hypothesize that this interaction between the vasculature and airway tree will affect the responses of the airways to endogenous and exogenous stimulation. To test this hypothesis we will quantify airway and regional vascular distensibility and their interaction using computerized reconstruction of the in vivo airway and vascular trees. We will also determine the progressive effects of increasing pulmonary edema on in situ airway size and regional vascular dimensions. The airway and vascular morphometric data will be applied to existing analytical models of the airway and vascular tree. I will also test the extent of regional airway response heterogeneity through the airway tree to physiologic stimuli known to worsen pulmonary status in clinical conditions, specifically, hypervolemia, hypovolemia, hypercapnia, and hypoxia. The results from all of these investigations will have a significant impact on our understanding and interpretation of pulmonary function in the clinical setting.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Clinical Investigator Award (CIA) (K08)
Project #
5K08HL002795-04
Application #
2210582
Study Section
Research Training Review Committee (RTR)
Project Start
1992-09-30
Project End
1997-09-29
Budget Start
1995-09-30
Budget End
1996-09-29
Support Year
4
Fiscal Year
1995
Total Cost
Indirect Cost
Name
Johns Hopkins University
Department
Anesthesiology
Type
Schools of Medicine
DUNS #
045911138
City
Baltimore
State
MD
Country
United States
Zip Code
21218
Brown, R H; Mitzner, W (1998) The myth of maximal airway responsiveness in vivo. J Appl Physiol 85:2012-7
Brown, R H; Georgakopoulos, J; Mitzner, W (1998) Individual canine airways responsiveness to aerosol histamine and methacholine in vivo. Am J Respir Crit Care Med 157:491-7
Brown, R H; Mitzner, W; Bulut, Y et al. (1997) Effect of lung inflation in vivo on airways with smooth muscle tone or edema. J Appl Physiol 82:491-9
Brown, R H; Mitzner, W; Wagner, E M (1997) Interaction between airway edema and lung inflation on responsiveness of individual airways in vivo. J Appl Physiol 83:366-70
Groeben, H; Brown, R H (1996) Ipratropium decreases airway size in dogs by preferential M2 muscarinic receptor blockade in vivo. Anesthesiology 85:867-73
Brown, R H; Mitzner, W (1996) Effect of lung inflation and airway muscle tone on airway diameter in vivo. J Appl Physiol 80:1581-8
Bulut, Y; Hirshman, C A; Brown, R H (1996) Prevention of lidocaine aerosol-induced bronchoconstriction with intravenous lidocaine. Anesthesiology 85:853-9
Brown, R H; Robbins, W; Staats, P et al. (1995) Prevention of bronchoconstriction by an orally active local anesthetic. Am J Respir Crit Care Med 151:1239-43
Brown, R H; Zerhouni, E A; Mitzner, W (1995) Visualization of airway obstruction in vivo during pulmonary vascular engorgement and edema. J Appl Physiol 78:1070-8
Brown, R H; Zerhouni, E A; Mitzner, W (1995) Airway edema potentiates airway reactivity. J Appl Physiol 79:1242-8

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