منابع مشابه
Resistance of Heidbrink-type expiratory valves.
The minimum resistance of expiratory Heidbrink-type value has been assessed by determining the pressure decrease across the values at a flow rate of 30 litre min--1. The average resistance of 70 valves currently in clinical use was 318 Pa at that flow rate and about 44% had resistances greater than the limit of 294 Pa previously suggested. The resistances obtained in new valves were either simi...
متن کاملFlow resistance of expiratory positive-pressure systems.
We measured the flow-resistance of five commercially available 10 cm H2O expiratory positive-pressure (EPP) valves (n = five per valve type) at bias flows of between 0 and 2,000 ml/s. We found that individual valves of each type and manufacturer functioned similarly. Different valve types, however, functioned differently: with one type, system pressure was higher than rated (p less than 0.05), ...
متن کاملA Primary Dead-Weight Tester for Pressures (0.05–1.0) MPa
Recent advances in technology on two fronts, 1) the fabrication of large-diameter pistons and cylinders with good geometry, and 2) the ability to measure the dimensions of these components with high accuracy, have allowed dead-weight testers at the National Institute of Standards and Technology (NIST) to generate pressures that approach total relative uncertainties previously obtained only by m...
متن کاملBronchial obstruction and reversibility in children: inspiratory or expiratory resistance?
Assessing bronchial obstruction and reversibility is of help in diagnosing asthma. The forced oscillation technique (FOT) has gained popularity in children since minimal cooperation is required. Owing to the fact that measurements are performed during tidal breathing, the upper airway may significantly impact on the respiratory resistance (Rrs) [1, 2]. The glottic aperture narrows during tidal ...
متن کاملEffect of albuterol on expiratory resistance in mechanically ventilated patients.
BACKGROUND In mechanically ventilated patients with COPD, the response of the expiratory resistance of the respiratory system (expiratory R(RS)) to bronchodilators is virtually unknown. OBJECTIVE To examine the effect of inhaled albuterol on expiratory R(RS), and the correlation of albuterol-induced changes in expiratory R(RS) with end-inspiratory resistance and the expiratory flow-volume rel...
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ژورنال
عنوان ژورنال: British Journal of Anaesthesia
سال: 1962
ISSN: 0007-0912
DOI: 10.1093/bja/34.5.290