Airway Resistance Measurements in the Internist's Office Routine determination in the diagnosis and care of breathless patients

Abstract

Certain limitations of conventional spirometry¹ imply that sophisticated appraisal of the presence and degree of physiologic dysfunction in patients with obstructive ventilatory disorders should include definition of the important pressure-volume-flow determinants of lower airway resistance. Macklem and Mead² have analyzed the complexities inherent in the use of pulmonary function tests dependent upon a forced expiratory maneuver as an index of airway dynamics. The usefulness of the whole-body, volume-displacement plethysmograph as a source of more critical estimates of airway resistance and airway responsiveness^3-8 has been documented beyond cavil. Payne and associates⁸ further suggest that estimates of bronchodilator drug potency, based upon spirometric changes alone, may be misleading in terms of locus of action by reflecting summation of various organ responses rather than the airway only.