Fast-responding automated airway temperature probe.

Rapid changes occur in the thermal profiles of asthmatic subjects following the cessation of hyperpnea, which include temperature increases of the order of 0.25 degrees C s-1 in the trachea. These thermal events could indicate abnormal blood flow in the airway wall of these patients, a factor which may be linked to the instability of their airway geometry. To monitor these events a series of fast-responding thermistors and associated electronics have been developed. The apparatus uses temperature sensors of very small mass and the interrupt processing capability of the IBM-AT compatible computer to achieve a system response time that is in an order of magnitude greater than previous devices. Stable, reproducible and easily calibrated, this device shows no hysteresis over a required operating range of 15-35 degrees C. It exceeds all standards for electrical safety of the American Hospital Association. This device can be used to monitor the thermal transients which are seen in the airways of asthmatic patients as their airways rewarm following hyperpnea.