A method of maintaining sterility of heated humidifiers in mechanical ventilator breathing circuits

Using the standard MA-1 breathing circuit, the Cascade Heated Humidifier and tubing become rapidly contaminated with patient organisms. The rapidity with which this occurs seems to depend on the quantity and quality of patient secretions and dumping infected water from lazy loops into the Humidifier. Following modifications to the ventilator circuit which included: (1) closed system humidifier filling, (2) the addition of a small copper trap and drainage system to the inspired side of the breathing circuit, and (3) alteration of the heater, no contamination of the humidifier contents occurred for periods as long as 28 days. This trap was manufactured in our hospital using standard plumbing fixtures; a commercial model is available. This system is applicable to any volume ventilator using a heated reservoir humidifier.