Microprocessor controlled flow regulated molecular humidifier

A method of humidifying breathable gas being supplied to a patient by a ventilator or an anesthesia circuit, the method comprising:

• directing the gas through substantially water saturated blotting paper;
• delivering an amount of water to the blotting paper;
• measuring at least two parameters;
• and
• regulating the amount of water delivered to the blotting paper based on the measured parameters to achieve a desired humidity level in the gas, said steps of directing, delivering, measuring and regulating together providing a gas having a molecular humidity substantially free of particulate water droplets at a humidity level in the range from approximately 28 to approximately 31 mg H.sub.2 O/l gas at approximately 37.degree. C.

A humidification system for humidifying breathable gas supplied to a patient by a medical gas delivery apparatus having inhalation tubing connecting from the apparatus to the patient and exhalation tubing extending from the patient, the system comprising:

• a humidifier disposed in the inhalation tubing adjacent to the patient;
• a flow meter for measuring a flow rate of the gas supplied by the gas delivery apparatus;
• a temperature probe for measuring a temperature of the gas delivered to the patient;
• a reservoir of water;
• piping carrying an amount of water from the reservoir to the humidifier;
• a controllable pulsing valve disposed in the piping between the reservoir and the humidifier and capable of limiting the amount of water delivered to the humidifier, said humidifier, said flow meter, said temperature probe and said controllable pulsing valve together providing a gas having a molecular humidity substantially free of particulate water droplets at a humidity level in the range of from approximately 28 to approximately 31 mg H.sub.2 O/l gas at approximately 37.degree. C.;
• and
• a microprocessor receiving a temperature measurement signal from the temperature probe and a rate of flow signal from the flow meter, and controlling the pulsing valve in response to the received signals and thereby controlling the relative humidity of the gas delivered to the patient.