An inexpensive servo-respirator based upon regulation of a shunt resistance.
We have designed and built an inexpensive servo-respirator for use in investigations of respiratory control in small animals. The device uses a butterfly valve to alter the resistance of an outflow shunt from a manifold that connects the animal's tracheal cannula to a pressure source. Tracheal pressure is regulated in response to a command provided by a suitably processed neural signal, often the integrated phrenic neurogram. As the valve opens, tracheal pressure approaches atmospheric; as it closes, tracheal pressure approaches the source pressure. An electronic controller circuit was developed to permit experimental procedures that include withholding volume delivery while maintaining a desired level of positive end-expiratory pressure. The device is able to track the neural command signal satisfactorily, and its performance appears to be limited primarily by the constraints applied by the respiratory system mechanics.
Daubenspeck
J A
JA
Department of Physiology, Dartmouth Medical School, Hanover, NH 03756.
Pichon
D
D
Knuth
K V
KV
Bartlett
D
D
St John
W M
WM
D000403:Airway Resistance; D000818:Animals; D002415:Cats; D004867:Equipment Design; D006801:Humans; D007700:Kinetics; D011312:Pressure; D012123:Pulmonary Ventilation; D012121:Respiration, Artificial; D014132:Trachea / Q000502:physiology; D012122:Ventilators, Mechanical