Chem/Physics
Week 2 Class Outline
7/14/1999

 

  1. Chemical and Physical Properties
    1. Compound Identification

      Physical properties: States: Of Matter which occupy space and have mass. It cannot be created or destroyed. Solids have definite shape and volume, liquids have definite volume but are variable in shape, and gases have neither definite shape or volume.
      Solubility: the amt of a given molecule that can dissolve into a solution.
      Specific Gravity: The wt of a substance compared with the wt of an equal amt of some other substance taken as a standard. For liquids the usual standard is water. It is measured by means of a hydrometer.
      Critical Temperature: The temp at which gas cannot be liquefied despite the amt of pres exerted on it. Critical Pressure is the pres needed to liquefy gas at its critical temp.
      Boiling Point: Temp when vapor pressure = atmospheric pressure and when all liquid goes into a vapor.

    2. Chemical Properties
      Stability      : The quality of maintaining a constant character despite forces that threaten to disturb it.
      Flammability: The ability of a substance to ignite
      Reactivity: The process or property of reacting
    3. Primary method of preparation
  2. Storage and Standards –
    1. Definition of compressed gas: a gas with a pressure exceeding 40 lbs per square inch (psi) at 70-degrees F, or a gas with a pressure greater than 104 psi at 130-degrees F, or a liquid with a vapor pressure greater than 40psi at 100-degrees F.
    2. Gas Cylinder construction - contains compressed gas or liquefied gas under pressure. The cylinders are color-coded which are different in the US and the rest of the world. The following are the colors in the US:

      Green is oxygen
      Gray is CO2, which is used for tourniquets or insufflation of lap surgery
      Brown is helium, which increases laminar flow and will deliver less turbulent air
      Blue is nitrous
      Yellow is air
      Black is nitrogen which usually powers heavy tools/instruments in the OR

    3. Cylinder volumes – important ones to remember are in an "E" cylinder:

      O2 = 660L
      Nitrous = 745 but this will remain constant until all the liquid has been used and just as there is just compressed gas remaining will the gauge cut the reading in half and once this gas is used up (usually quickly) the tank will read 0. Other things to remember are the service pressure of O2 is 1900-2100, Air is 1800

    4. Content evaluation – All cylinders are tested within 5/3 of their service pressure.
    5. Regulating agencies – 9 different agencies regulate the tanks

DOT – handling and transport, construction of bottles
Am Society for Testing Materials Committee – review and recommends manufacturing standards for respiratory therapy and anesthesia equipment
Interstate Regulations – fire marshal
OSHA – employee protection, decided an OR must have air exchanged 15xhour, recommend having a gas scavenging system
FDA – stand for medical gas purity, true and honest labeling
Am. Nat. Stand Institute – dictate safety and performance stand for equipment
CGA –Compressed Gas Assoc – tanks meet stand
JCAHO

  1. Pharmacopoeia – umbrella regulating develop purity standards
  2. Coding systems - color-coding and pin indexing system. The pin index is a safety system to prevent the attachment of the wrong gas cylinder to the yoke of an anesthesia machine. O2 is 2-5 while N2O is 3-5.
  3. Safe use of cylinders – use of color coding and pin index systems, store in a cool, well-ventilated place, away from open flames. Should never be exposed to temps> 130-degreesF. The valve is the most susceptible to damage and needs to be protected by caps when not in use.
  4. Color marking designation – as above

 

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