Abstract: A plethysmograph is described that includes a test chamber having an opening; a sealing member including an annular flexible seal to receive at least a part of the head of the test animal mounted across the opening whereby the animal breathes air outside the test chamber, while the animal's body is within the test chamber; and a restraining member attachable to the sealing member, the restraining member including a clamp positionable behind the test animal's head, to prevent the animal from withdrawing its head from the restraining member. The animal is positioned in the restraining member and the sealing member is attached to the restraining member before insertion of the animal and assembly into the test chamber, avoiding previous difficulties in simultaneously placing an animal into the chamber while inserting the animal's nose into the seal. The plethysmograph also eliminates the necessity for a plunger to prevent rearward movement of the animal.

Abstract: A plethysmograph is described that includes a test chamber having an opening; a sealing member including an annular flexible seal to receive at least a part of the head of the test animal mounted across the opening whereby the animal breathes air outside the test chamber, while the animal's body is within the test chamber; and a restraining member attachable to the sealing member, the restraining member including a clamp positionable behind the test animal's head, to prevent the animal from withdrawing its head from the restraining member. The animal is positioned in the restraining member and the sealing member is attached to the restraining member before insertion of the animal and assembly into the test chamber, avoiding previous difficulties in simultaneously placing an animal into the chamber while inserting the animal's nose into the seal. The plethysmograph also eliminates the necessity for a plunger to prevent rearward movement of the animal.

Abstract: An integrated respiratory ventilation system and method for its calibration is described. The system includes a ventilator having air conduits, transducers adapted to emit signals proportional to the level of air pressure or air flow within the air conduits, and inspiration, expiration and exhaust ports. A processor-controlled calibrator is in communication with one or more of the air conduits. A preferred calibrator includes a water-filled outer column and a vertically aligned inner column extending into the outer column, the inner column having an upper end in communication with at least one of the ports. A processor controls the opening and closing of the ports and the level of air pressure in, and air flow from, the inner column to measure the level of transducer signals at two known pressures and two known flows. The processor uses the measured transducer signals to calibrate the transducer.

Abstract: A plethysmograph is described that includes a reference chamber having a top wall, a bottom wall, a barrier wall spaced beneath the bottom wall, a continuous side wall having a lower edge, and a first continuous flange with a lower edge below the bottom wall and above the barrier wall; a test chamber having a bottom wall, a continuous side wall with an upper edge, and a second continuous flange extending upwardly from the upper edge, the interior face of one of the flanges including an annular groove with an O-ring in the groove, and the interior face of the other flange being tapered from vertical by up to about 1°; and a manifold having airflow openings in communication with the reference and test chamber and a common exterior airflow opening through a passageway, and a sampling port in communication with the passageway.

Abstract: A plethysmograph is constructed with a base including parallel, horizontal guide rails; an open-ended, moveable enclosure section having a horizontal central axis slidable on the guide rails between open and closed positions; a fixed enclosure section mounted on the base transverse to the horizontal pathway, the fixed enclosure section including an inner face toward the open end of the enclosure section adapted for sealing engagement with the open end of the moveable enclosure section when the moveable enclosure section is in its closed position; and a support table attached to the fixed section, the table projecting into the moveable enclosure section when the moveable enclosure section is in the closed position, the table being vertically adjustable and having an angularly adjustable longitudinal axis.

Abstract: A cough event is differentiated from a sneeze event of a test subject enclosed within a plethysmograph test chamber by measuring air pressure changes during the event, and comparing the pressure changes against criteria indicative of a cough to determine the likelihood that the event is a cough. Air pressure changes are recorded as pressure and/or sound values. A graphical record of a waveform of changes in the air pressure during an event relative to a baseline value is recorded, and a value is calculated that is indicative of the likelihood that the event is a cough based on the sizes of areas between the waveform and baseline during the event, said areas including a first area indicative of the change in air pressure during air inspiration, a second area indicative of the change in air pressure during air compression, and a third area indicative of the change in air pressure during expiration.

Abstract: The accuracy of measurements of changes in air volumes within a plethysmograph is improved by addition of a manifold to provide a common source of exterior air to the plethysmograph test and reference chamber. The preferred plethysmograph includes test and reference chambers divided by a common separator wall, pneumotachs in communication with the chambers, and a differential pressure transducer having a first inlet in communication with the test chamber and a second inlet in communication with the reference chamber. The manifold includes an exterior air inlet and a passageway extending between the two pneumotachs and the air inlet. The passageway may be in the form of separate tubes or conduits, or a common housing covering the pneumotachs. Preferably, the distances from the exterior air inlets to the two pneumotachs are approximately the same.

Abstract: A whole body plethysmograph for pulmonary measurements of unrestrained small animals includes a cylindrical animal chamber and an integral reference chamber. The animal chamber and the reference chamber each include ports for receiving transducer nipples. The animal chamber and the reference chambers also include ports for selectively venting each of the chambers. A port is mounted in a bulkhead which separates the animal chamber and the reference chamber, and a length of tubing extends from the valve into the reference chamber for providing a high resistance bleed path between the animal chamber and the reference chamber. The plethysmograph further includes an aerosol manifold in the top of the animal chamber. The aerosol manifold includes a plurality of radially extending apertures for uniformly distributing the aerosol in the animal chamber. The plethysmograph still further includes two pneumotachographs in the top of the animal chamber.