Medical gas Flashcards
-Medical Gas Therapy Oxygen
-Characteristics
-Colorless, odorless, transparent, tasteless, naturally occurring -Not very soluble in water -Not flammable , but supports combustion -Fraction of oxygen in the air around us remains constant at 20.95 or 21% (FiO2 of inspired oxygen)
-Photosynthesis: O2 is naturally produced (plants)
-Production otherwise done by
-Electrolysis of water -Fractional distillation of air -Most common and least expensive -FDA requires purity of at least 99.0% -Physical separation -Oxygen concentrators, used in the home, some long term facilities -Molecular sieves/ filtration -Pull air in room thru a semi-permeable plastic membrane and remove nitrogen
-Air
-Characteristics
-Colorless, odorless, tasteless -Naturally occurring mixture that consist of 20.95% oxygen and 78.1% nitrogen , and approximately 1% trace gas mainly argon -Supports combustion -Medical grade air (AKA room air) -Produced by filtering and compressing atmospheric air -Must be dry, free of oil or other particulate contaminants. -Standard working pressure of 50 PSIG
-Carbon Dioxide (Co2)
-Characteristics
-Colorless, odorless -1 ½ times heavier than air -Does not support combustion or maintain animal life -Mixture of oxygen with 5% to 10% of Co2 -Historically, atelectasis, hyperventilation -Today use is limited -Heart lung machines -Calibration of blood gas machines -Used in some congenital heart disorders and abdominal surgeries
-Helium (HE)
-characteristics
-Odorless, tasteless, nonflammable
-Second only to hydrogen as lightest gas
-Chemically and physically insert, cannot support life -Can be mixed with at least 20% oxygen to form heliox, we use in respiratory care to -Manage severe cases of airway obstruction -Low density of helium decreases work of breathing. Can bypass obstructions and pull oxygen with it down into the lungs
-Nitrous Oxide (N2O)
-Characteristics
-Colorless
-Slightly sweet odor and taste
-Can support combustion
-Cannot support life, always mix with at least 20% oxygen
-We know as laughing gas
-Use
Anesthetic agents
-Nitric Oxide (NO)
-Characteristics
-Colorless
-Nonflammable
-Toxic gas
-Supports combustion
-Vasodilator, relaxes smooth muscles of the lungs
-FDA has granted approval for delivery of NO through INO therapeutics inc. Its used as a pulmonary vasodilator for pulmonary hypertension ARDS, and refractory hypoxemia
-Cylinder sizes and contents
-Letter designation for different sizes
-AA-E “small cylinders, used for transport -Unique valves & connecting mechanisms -Small cylinders, post valve and yoke connector -Large cylinders (F through H&K) threaded valve outlets
-Cylinder use
-Secure cylinders at patient bedside
-Do not use flammable materials especially oil or grease on regulators, cylinders, filters, or valves -Never cover a cylinder with any material including bed linens or hospital gowns -Open the cylinder valve slightly to remove dust before attaching the regulator -Make sure nobody is in front of the tank -”Cracking the cylinder”
-Regulating gas pressure and flow
-If
-Goal is just reduce pressure, a reducing valve is used -Goal is to control flow of gas , a flow meter is used -Goal is to reduce pressure and control flow of gas a regulator is used -”working” pressure 50 psig in USA
-High pressure reducing valves
-Can be preset or adjustable
-Adjustable reducing valve can increase or decrease pressure to increase or decrease flow -Commonly used with bourdon type flow meter (combination of flow meter and reducing valve is called a regulator)
-flow pressure meter
-medical gas is a drug, must know dose given
-Often described as flow rate or lpm (liter per minute) -When source of O2 is from bulk central supply only need flow meter to administer instead of regulator
-3 TYpes of dosage regulation and administration
-Flow restrictor, the bourdon gage, the thorpe tube
-Flow restrictor
-Simplest and least expensive
-Fixed orifice that delivers a preset flow -Gravity independent (can be used in any position)
-Bourdon gauge
-Always used in conjunction with adjustable pressure reducing valve
-operates under variable pressure -Not altered by gravity, device of choice for transport -Disadvantage, inaccuracy when pressure downstream changes, downstream flow increases -Output flow even if outlet is blocked
-Thorpe tube
-Used in bedside wall outlet station or on cylinders with reducing valve
-Variable orifice -Tapered transparent tube with a float inside -2 Types: pressure compensated (ball will bounce when plugged into wall) and pressure uncompensated thorpe tube -When floe resisting equipment is connected, if compensated. Meter will indicate actual flow if outlet blocked if uncompensated: if a block in downstream pressure, tube will show a flow even if none is being delivered -Affected by gravity, accurate only in upright position.
-Storage of Medical Gases
-Cylinders
-Portable high pressure -Compressed gas or liquid -Contruction -Seamless Steel -Classified by the Department of Transportation (DOT) -3A-Carbon steel -3AA- steel alloy tempered for high strength
-Marking and Identification of Cylinders
-Metal stamping on the shoulders
-Letters DOT or ICC (interstate commerce commission) followed by cylinder classification
-Normal filling pressure PSI -Letter size of Cylinder (E<G<H<K and so on) -Cylinder serial number -Mark of ownership followed by the manufacturing stamp or mark identifying intersecting authority
-Original safety test date and subsequent test dates
-test performed every 5 to 10 years (specified by DOT regulations)
-Marking and Identification of Cylinders
-Symbols on the tank
-EE- Elastic expansion
-(*) indicates approval for 10 years
-(+) cylinders approval for filling 10% above service pressure
-Satiety index connector system
-Primary purpose prevents misconnection between equipment and incorrect gas
-3 Basic indexed safety system for tanks -American standard safety system (ASSS) -Pin Index safety system (PISS) -Diameter index safety system (DISS)
-American Standard Safety System (ASSS)
-Threaded high pressure connection between large compressed gas (large tank F though H/K) and their attachments
-Pin Index Safety System (PISS)
-High pressure connections for small cylinders (E-Smaller)
-Yoke fits connectors -Yoke fits over valve stem -2 pins projecting from yoke fit into 2 pin holes drilled in stem of tank -When pins positioned property, small received nipple of yoke lines up with recessed cylinder valve outlet -Nyon washer or bushing, used to ensure a leak free connection -Position of pins and pinholes vary for each gas type. 10 possible pin combinations, used most often are -Oxygen 2-5 -Air 1-5
-Diameter index safety system (DISS)
-Externally threaded body and mated nipple with a nut (basically any respiratory equipment that hooks into the wall has a DISS connected)
-Prevent accident interchange of low pressure medical gas connectors -Most common are quick connect system, not interchangeable between manufacturers
-Gas Cylinder Safety
-Overseeing agencies
-National fire protection agency (NFPA)
-Compressed gas association (CGA)
-Gas Cylinder Safety
-Storage
-in racks or chain cylinder to wall
-Away from source of heat (below 125 F) -Flammable gasses separated from gasses that support combustion -Protective cap on cylinder not in use -Segregate full and empty cylinder, store separately if possible -Post sign that cautions regarding presence of oxidizing gas and alerts against smoking. This sign must be readable from a distance of at least 5 feet -Liquid oxygen, cool well ventilated area (small amounts of oxygen vent from low pressure containers, wear gloves and eye protection when filling tanks
