A technique for monitoring respiratory responses in guinea pigs.

A piezoelectric crystal was used to detect respiration rates and pulmonary retractions of guinea pigs in response to intratracheal administration of histamine. Voltage output from the crystal was displayed on a recorder for visual processing and interfaced to a microcomputer for automatic data processing. Using intratracheal instillation of histamine, this system accurately reproduced the visual observations of respiratory responses in guinea pigs.