ISO 8185 Humidifiers for medical use – General requirements for humidification systems
ISO 8185:1997 Introduction
Humidifiers are used to raise the water content of gases delivered to patients. Gases available for medical use do not contain sufficient moisture and may damage or irritate the respiratory tract of dessicate secretions of patients whose supraglottic airways have been by-passed. Heat may be employed to increase the water output of the humidifier.
In addition, many humidifiers utilize heated delivery tubes in order to increase the operating efficiency and reduce excessive water and heat loss. Ventilator and anesthesia delivery tubes in common use may not withstand the heat generated by the humidifiers and heated delivery tubes mechanisms.
Many humidifier manufacturers use off-the-shelf electrical connectors for their electrically heated delivery tubes. However, since different manufacturers have used the same electrical connector for different power outputs, electrically heated delivery tubes may be physically, but not electrically, interchangeable. Improper electrically heated delivery tubes use has caused overheating, circuit melting, patient and care-giver burns, and fires. Reduction of the relative humidity at the patient connection port may cause desiccation of tracheo-bronchial secretions (see reference , annex T). It was not found practical to specify the interface requirements for electrical connectors to ensure compatibility between humidifiers and delivery tubes produced by different manufacturers.
Since the safe use of a humidifier is dependent on the interaction of the humidifier with its many accessories, this International Standard ISO 8185 sets total-system performance requirements, including accessories such as delivery tubes (both heated and nonheated), temperature sensors, and devices intended to control the environment within these delivery tubes.
A rational for the most important requirements is given in annex S. It is considered that a knowledge of the reasons for the requirements will only facilitate the proper application of this International Standard ISO 8185, but will expedite any subsequent revision.
ISO 8185:1997 Scope
Clause 1 of IEC 60601-1:1988 applies with the following amendment: ISO 8185 is one of a series of International Standards based on IEC 60601-1; in IEC 60601-1 (the “General Standard”), this type of International Standard is referred to as a “Particular Standard”. As stated in 1.3 of IEC 60601-1”1988, the requirements of this International Standard ISO 8185 take precedence over those of IEC 60601-1.
Humidifiers may be gas-powered, electrically-powered, or both. However, this International Standard ISO 8185 has been prepared as a Particular Standard based on IEC 60601-1, which gives general requirements for all aspects of safety, not only electrical safety, and many of the ISO 8185 requirements are therefore applicable to humidifiers not powered by electricity. Where this International Standard ISO 8185 specifies that a clause of IEC 60601-1 applies, it means that the clause applies only if the requirement is relevant to the humidifier system under consideration.
This International Standard ISO 8185 includes requirements for the safety and performance of humidifiers, as defined in 1.3.107, suitable for inclusion in breathing systems. This international Standard ISO 8185 also includes some requirements for delivery tubes, including heated delivery tubes (heated-wire delivery tubes), and devices intended to control these heated delivery tubes, heated delivery tube controllers.
This International Standard ISO 8185 is not applicable to heat and moisture exchangers (HMEs). This International Standard ISO 8185 is not applicable to devices commonly referred to as “room humidifiers” and humidifiers used in heating, ventilation and air conditioning systems, and humidifiers incorporated into infant incubators. This International Standard ISO 8185 is not applicable to nebulizers used for the delivery of drugs to patients.
Note of Our Interest:
Our interest in this standard is the ring gage defined in the appendixes. ISO 8185:1997 identified this ring gage as ISO 8185 Fig Q.1. With the release of ISO 8185:2007 the identical ring gage was reidentified as ISO 8185 Fig DD.1.
Original Posting: 1/14/2013
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