Related Experiment Video
Updated: Jun 24, 2026

A Reversible, Non-invasive Method for Airway Resistance Measurements and Bronchoalveolar Lavage Fluid Sampling in Mice
Published on: April 14, 2010
Determining changes in airway caliber in asthma: the role of submaximal expiratory flow rates
Abstract:
Sixteen patients with suspected reversible airway obstruction who had previously demonstrated an increase in specific airway conductance after isoproterenol, but who had not demonstrated an increase in forced expiratory flow were studied using a measurement of submaximal flow. Flow during tidal breathing (VTV) was measured spirometrically, and VTV increased in all 16 patients from a value of 0.61 L/sec before isoproterenol to 0.80 L/sec after isoproterenol. In addition, each of these 16 patients experienced a significant increase in vital capacity and a significant decompression of functional residual capacity after isoproterenol. If plethysmography is not available, the measurement of VTV may provide evidence of bronchodilatation. The mechanism responsible for the dichotomy between maximal and submaximal flow is the compression of airways by high positive pleural pressure which is present during maximal, but not submaximal maneuvers.
Related Concept Videos
Respiratory Volumes
Tidal Volume (TV) Tidal volume (TV) is the air inhaled or exhaled in a...
Pressure Relationships in Thoracic Cavity
Breathing Mechanisms
Both intra-alveolar and intrapleural pressures rely on specific lung properties. The ability to breathe—allowing air to enter the lungs during...
Factors Affecting Pulmonary Ventilation
Alveolar Surface Tension
The alveolar fluid lines the luminal surface of the alveoli and exerts a force called surface tension. This force is caused by the polar water molecules in the liquid being more strongly attracted to each...
Chronic Obstructive Pulmonary Disease-IV: Assessement and Diagnostic Studies
Medical History
Asthma I: Introduction
Asthma III: Clinical Manifestations

