A phrenic nerve-actuated electronically controlled positive-pressure ventilator.
We have constructed an electronically controlled positive-pressure ventilator actuated by phrenic neural activity for use in open-chested or paralyzed experimental animals for the study of breathing pattern. A Bird Mark 14 positive-pressure ventilator was modified such that flow is a linear function of a command signal. Flow is delivered by advancing an air valve with a servo-motor that is controlled by one of three different operational modes. In two of the modes, the difference between the electronic average of inspiratory phrenic activity (moving average) and a feedback signal determines the inspiratory flow. The feedback signal is derived from either tracheal pressure or an electronic measure of inspired volume. In the third mode, the moving average is differentiated to provide control of inspiratory flow and volume. Physiological flow profiles were created using all three operational modes. Integration of an air-valve position signal provides an electronic measure of tidal volume. An additional feature of this ventilator allows inspiratory flow and duration to be predetermined for a given breath.
Schertel
E R
ER
Schneider
D A
DA
Howard
D L
DL
Green
J F
JF
D000818:Animals; D004285:Dogs; D004558:Electric Stimulation; D004582:Electronics, Medical; D010791:Phrenic Nerve / Q000502:physiology*; D011175:Positive-Pressure Respiration / Q000295:instrumentation*