In the inhalation side of breathing system upstream of any antibacterial filters, humidifiers and other such medicating devices. . In confined volumes such as in incubators or tents. When analyzing for oxygen in breathing systems, the flow diverter must be used. The diverter should be screwed onto the threaded front end of the R17MED sensor. A tee adapter (plastic, P/N A268, or metal, P/N A283) should be placed into the breathing loop, and the above sensor assembly plugged into the tee adapter. See Figure 2-3. CAUTION: CHECK THE BREATHING SYSTEM FOR LEAKS. BE CERTAIN THAT THE SYSTEM DOWNSTREAM OF THE SENSOR DOES NOT PRO DUCE ANY BACKPRESSURE OR RESTRICTION TO FLOW. ERRORS IN READINGS WILL RESULT IF THIS IS NOT FOLLOWED. THE OXYGEN SENSOR IS A NON-STERILE DEVICE AND SHOULD BE USED IN CONJUCTION WITH AN ANTI-BACTERIAL FILTER. ALWAYS INSTALL THE SENSOR ON THE INSPIRED LINE AHEAD OF FILTERS, HUMIDIFIERS AND MEDICATING DEVICES. NEVER INSTALL THE SENSOR IN A LOCATION THAT WILL EXPOSE THE SENSOR TO PATIENTS’ EXHALED BREATH OR SECRETIONS UNLESS YOU INTEND TO DISPOSE OF THE SENSOR AND FLOW ADAPTER AFTER USE. When monitoring for oxygen in confined volumes such as incubators, hoods, etc., the flow diverter must be removed from the R17MED sensor so that it does not interfere with the rapid exchange of gases to and from the sensing surface of the sensor. Failure to remove the diverter in these applications may adversely affect the response time of the sensor. The R17MED sensor can be placed or hung inside incubators, tents, etc. When it is necessary to thread the cable through a small hole in order to gain access to the inside of a chamber, the cable should be disconnected at the sensor, threaded through the hole, and reconnected inside the chamber. Teledyne Analytical Instruments 17 Operating Instructions MX300 2.3 Factors Affecting Sampling Accuracy 2.3.1 Humidity Humidity does not directly affect the accuracy of the sensor's measurement. However, when a nebulizer or other device is used to increase moisture levels in gas mixtures, the moisture actually dilutes the mixture. This dilution effect decreases the oxygen concentration. Your portable oxygen Monitor accurately measures the decreased oxygen concentration. As with all diffusion based oxygen sensors, excessive condensation on the sensing surface of the R17MED will block the diffusion of oxygen to the sensor, rendering it inoperative. We recommend installing the sensor on the dry side of the breathing system at all times. 2.3.2 Temperature The R17MED oxygen sensor compensates for ambient temperature changes in the range of 0–40°C (32–104°F). Since the thermistor that compensates for these changes is located in the rear of the sensor assembly, it is important that gas mixtures, flowing over the front of the sensor, be at room temperature, which is assumed to the temperature around the rear of the sensor. Reading errors may occur if gases at higher temperature from devices such as heated humidifier are used to measure oxygen with R17MED oxygen sensor. A small thermal tracking error may be encountered in applications where the entire sensor assembly is placed in the gas mixture to be analyzed (such as in the incubators). Holding the sensor in your hand for more than a few minutes can also affect the temperature tracking which appears as a slow drift on the LCD. No adjustments should be made during this period since this error will be eliminated when both the thermistor and sensing electrode have had sufficient time to come to thermal equilibrium. This can take up to 2 hours. 2.3.3 Pressure Virtually all gas sensors and monitors measure the partial pressure of the gas that they sample. The only time that these monitors can accurately read percentages is when the total pressure does not vary over time between calibrations and use. For this reason it is important to calibrate the MX300 Oxygen Monitor (with R17MED oxygen sensor) at regular intervals. It is recommended that the Monitor be calibrated prior to each use or every 8 hours, and at the same pressure the monitor normally operates after calibration. If the gas being monitored flows through some length of tubing, use similar tubing/apparatus and same pressure/ flow rates when calibrating the Monitor. Teledyne Analytical Instruments 18 Portable Oxygen Monitor Operating Instructions When a ventilator is a part of the breathing system, the alternating “breathing” pressure cycles generated by the ventilator will be sensed as pressure pulses by the sensor, and over time, such pulses manifest as pressure increases in the fast-reacting sensors such as R17MED. This perceived pressure increase results in correspondingly higher oxygen reading. While the concentration of oxygen is not changing, it is the total pressure that is increasing producing a corresponding increase in the partial pressure of oxygen. 2.3.4 Discrepancy in Readings When a discrepancy in oxygen readings is detected, the Monitor’s readings should be verifi...