Importance

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Abstract

A device and method for determining and acting upon the pressure in a balloon sleeve which closes a tracheal tube in the trachea of a patient comprises an inflation cannula which is connected to a pump and valve arrangement for inflating the sleeve. A pressure-to-voltage converter is connected to the cannula for sensing an instantaneous static pressure in the cannula. A differentiator is connected to the converter for differentiating the static pressure to produce a signal corresponding to pressure variations in the sleeve. The varying voltage corresponding to the pressure variations is then rectified and integrated to produce a signal that rises and falls with rising and falling frequency of pressure variations in the sleeve. If the rate becomes too high or too low, a signal is generated which is then again integrated to provide for transient unacceptable conditions. If upon integration it is found that the rate continues to remain too high or too low, the circuit for deflating the sleeve is activated to inflate the sleeve over the cannula. A respirator which is being used in conjunction with the tracheal tube can simultaneously be switched from a closed circuit ventilation mode to an open circuit ventilation mode. Warning lights and an audible alarm can be used in conjunction with limit value switches to provide visual and audible indications to an operator representing the pressure condition within the balloon sleeve.

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First Claim