PEAK EXPIRATORY FLOW AS AN EASY SPIROMETR IC METHOD FOR MEASURING STENOSES OF THE LARYNX AND TRACHEA

Body plethysmographic and spirometric indices can be used for routine examinations of obstructive lesions of the larynx and upper trachea. T otal resistance, forced expiratory volume in 1 sec (FEV 1) and the S-s haped flow-pressure loop can show clinically significant extrathoracic stenoses. We have now also measured peak inspiratory flow (PIF) and p eak expiratory flow (PEF) with a peak flow meter. Easy handling was co mpared with good reliability of the measurements and possible detectio n of laryngeal lesions. Extrathoracic stenoses caused turbulent flow, with a flow-dependent increase in total resistance (R(tot)). This resi stance increased only with severe stenoses, while mild stenoses were o ften not detected. Peak expiratory flow reacted earlier than did peak inspiratory flow and seemed to be the most reliable parameter for dete cting an extrathoracic stenosis. Testing was easy to perform and was u sually reproducible. Patients with additional peripheral obstructive s tenoses required a more specific examination.