title: An elastic loading system for ventilatory studies in small animals.
abstract: A system for studying the effects of prolonged inspiratory elastic loading in small animals (300-500 g) is described. A voltage comparator triggered by the expired flow signal activates a solenoid valve to vent the loading chamber after each inspiratory decompression, ensuring the presentation of a constant extrapulmonary elastance. The sensitivity of the comparator (5 mV) and the response time of the venting circuit (40 ms) make this system suitable for use in small subjects with tidal volumes less than 1 ml and respiratory frequencies exceeding 100 breaths . min-1. Additionally, the composition of the inspiratory gas is easily altered and a built-in device allows end-expiratory occlusions to be performed.
mesh_terms: D000818:Animals; D010827:Physiology / Q000295:instrumentation / Q000379:methods*; D051381:Rats; D012119:Respiration; D014939:Work of Breathing