The American review of respiratory disease
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This study was designed to: (1) determine the performance characteristics of available spirometers; (2) assess the practically and applicability of the American Thoracic Society's (ATS) Snowbird Workshop recommendations on Standardization of Spirometry; and (3) determine whether spirometer testing could be done with room air. Nineteen spirometers were tested with 16 different forced vital capacity waveforms. Fourteen spirometers met the ATS forced vital capacity requirements. ⋯ The testing methods recommended by ATS need to be expanded to include more patient waveforms. Testing with room air is easier and simpler and, for most devices, just as effective as heated and humidified air. We conclude that most available spirometers can faithfully record forced spirograms and that if a spirometer meets the ATS requirements, it makes no difference on which device the spirogram is recorded.
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Am. Rev. Respir. Dis. · Jan 1980
Case ReportsNon-organic acute upper airway obstruction: description and a diagnostic approach.
We describe 3 cases of upper airway obstruction in which no organic cause could be identified. All 3 patients presented with severe dyspnea and stridor. Direct laryngoscopy and bronchoscopy failed to demonstrate any lesion. ⋯ Plethysmographically measured airway resistance was normal in the 2 patients for whom it was obtained. We believe a functional etiology should be added to the possible causes of acute upper airway obstruction. This entity can readily be identified by the marked discrepancy between inspiratory flow limitation and airway resistance.
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Painful unanesthetized arterial puncture may produce transient hyperventilation, and this hyperventilation might alter resting values of arterial pH and PCO2. We investigated this possibility by comparing pH and PCO2 values of blood samples obtained by arterial puncture with values of arterialized venous blood obtained by a painless method. ⋯ The variation (SD) in PCO2 within an individual subject was +/- 1.7 mm Hg, which was almost identical to the inherent precision of the Radiometer ABL-2 acid base laboratory (SD, +/- 1.32). We conclude that an unanesthetized arterial puncture provides an accurate measurement of resting pH and PCO2.