BT_SQ 1.6 CO2 Analysis

Back to an old favourite LO 😉

BT_SQ 1.6 Describe the methods of measurement applicable to anaesthesia, including clinical utility, complications and sources of error in particular:
· Gas analysis, including capnography

TRUE/FALSE The 90-95% response time for a CO2 analyser should be less than 150ms
TRUE/FALSE Volatile agents can be distinguished from each other by measuring infrared absorbance at 3.3µm
TRUE/FALSE Collision broadening means that the absorption peak for CO2 at 4.3µm is made wider in the presence of Nitrous Oxide
TRUE/FALSE Infrared analysers measure gas concentration rather than partial pressure
TRUE/FALSE Water is a powerful absorber of infrared light

A couple of follow on questions:

  1. Why is the 90% response time important in a CO2 analyser? The answer is related to what you have learned about requirements for invasive pressure monitoring.
  2. What is the device in the picture below? What is it used for? How does it work?


2 thoughts on “BT_SQ 1.6 CO2 Analysis

  1. The device forms part of the sampling tubing of a side-stream gas analyser. The tubing is made of nafion. This polymer has a number of interesting properties, one of which is of particular importance to infrared gas analysis. The tubing is mentioned in Magee & Tooley on page 228, although not by name.


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