Teledyne AX300-I manual Discrepancy in Readings

Service Manual AX300-I

When the sensor is connected to a ventilator circuit, the alternating “breathing” pressure cycles generated by the ventilator will be sensed as an increase in the oxygen percentage (especially if the sensor is fast enough to sense the changes, as is the R17MED). In reality, the percentage of oxygen is not changing; it is the total pressure that is increasing producing a corresponding increase in the partial pressure of oxygen. A hundred centimeter of water pressure pulse will produce a 0.11 atmosphere, or an 11% increase in the total and therefore partial pressure of oxygen. Assuming that the sensor is fast enough to track this pressure pulse, an un-pressurized reading of 50% oxygen will increase to 55.3% if the sensor is subjected to a pressure cycle of 100cm H2O. The reading will rise proportionally less for smaller pressures.

3.6.4 Discrepancy in Readings

The AX300-I instrument should be used to measure the oxygen concentration exiting another oxygen mixing device or life support system (i.e., a blender, incubator or anesthesia machine). The information obtained from the AX300-I should never be used to adjust a life-support system, but should only be used as an indication that the life support system or device may require service and/or calibration.

When a discrepancy in oxygen readings is detected, the oxygen analyzers readings should be verified by checking the AX300-I battery condition and calibration using 100% oxygen. If the analyzer can be calibrated, the unit can be assumed to be in good working order and capable of providing readings to specification. If, after reinstalling the unit, the discrepancy in oxygen readings persists, the problem is most likely elsewhere (i.e., flow blockage, primary device error, etc.). Further investigation should be made until the discrepancy in readings is resolved. The troubleshooting section of this manual may provide additional assistance in locating the problem.

Note: The MSDS on this material is available upon request through the Teledyne Environmental, Health and Safety Coordinator. Contact at (626) 934-1592

3.6.5 Anesthetic Gases

3.6.5.1GASES THAT INDUCE READING ERROR

When using the R17MED sensor in the presence of anesthetic gases such as Halothane, the oxygen reading may fall (see Table below). The magnitude of this error will depend upon the level of oxygen and the duration of exposure.

The anesthetic agents listed in the following table (Halothane, Enflurane, Isoflurane, Sevoflurane, and Desflurane) were vaporized into a stream of 30%

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