[Peak flow measurement in patients with laryngeal and tracheal stenoses. A simple and valuable spirometric method]

Body plethysmographic and spirometric indices can be used for routine examinations of obstructive lesions of the larynx and upper trachea. Total resistance, forced expiratory volume in 1 sec (FEV1) and the S-shaped flow-pressure loop can show clinically significant extrathoracic stenoses. We have now also measured peak inspiratory flow (PIF) and peak expiratory flow (PEF) with a peak flow meter. Easy handling was compared with good reliability of the measurements and possible detection of laryngeal lesions. Extrathoracic stenoses caused turbulent flow, with a flow-dependent increase in total resistance (Rtot). This resistance increased only with severe stenoses, while mild stenoses were often not detected. Peak expiratory flow reacted earlier than did peak inspiratory flow and seemed to be the most reliable parameter for detecting an extrathoracic stenosis. Testing was easy to perform and was usually reproducible. Patients with additional peripheral obstructive stenoses required a more specific examination.