Techniques and Procedures I RC 170

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Techniques and Procedures IRC 170

• Medical Gas Supply systems
• Unit II
• By
• Brian Cayko, MBA., RRT.

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Tank Jockeys O2 Monkeys

• Historically the primary role of OJT Resp techs
  was to supply deliver O2 tanks to patient care
  areas
• Though we have evolved, delivery of medical gases
  remains key
• Therapeutic gases
• Used to relieve symptoms improve hypoxemia
  Lexicon

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Oxygen (O2)

• Characteristics
• Colorless
• Odorless
• Transparent
• Tasteless
• Nonflammable
• Supports combustion
• Concentration Pressure influence rate

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O2 Production

• Frax Distilax
• Physical Seperax

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O2 Producx

• Frax Distilax
• Most common, least expensive
• Method
• Air is filtered
• Then liquefied by comprex, cooled by rapid expanx
  (JT effect)
• The resulting N2 O2 mix is heated slowly in
  distillation tower
• N2 boils off first, liquid O2 remains
• Either stored as liquid in cryogenic cylinder or
  as gas in compressed gas cylinder
• 99.5 pure, FDA requires at least 99.0

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O2 Producx

• Physical Separax
• Molecular Sieves
• Inorganic Sodium Aluminum Silicate Pellets
• Absorb N2, trace gases, water vapor
• gt90 O2 concentrax
• Semi-permeable membrane vacuum
• 40 O2 concentrax
• Utilized by O2 Concentrators for home caer use
  (Low Flow)

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Air

• Colorless
• Odorless
• Density 1.29g/L at STPD
• Used as standard for measuring specific gravity
  of gases
• Medical gas must be dry free of
  oil/contanimants
• Cooled to dry
• Filter to clean
• Standard Working Pressure for Medical gases 50
  psi
• Home compressors available providing much lt 50psi
• Ideal for SVN
• Never for vent or other pneumatically powered
  equip.

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Composition of Room Air

• Nitrogen 78.08
• Oxygen 20.946
• Argon 0.934
• Carbon Dioxide 0.0335
• Helium 0.000524
• Nitrous Oxide 0.000114

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Carbon Dioxide (CO2)

• Colorless
• Odorless
• Does not support combustion or maintain animal
  life
• 1.5 xs heavier than air, i.e. specific gravity
  of 1.5

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CO2

• Uses
• Historically
• Singultus or hiccups
• Resorbtive Atelectasis
• Current
• Membrane oxygenation (heart/lung machine)
• Co-oximetry calibration
• 1 is for acid/base balance of blood, diagnostic

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Helium (He)

• Odorless
• Colorless
• Non-flammable
• Poorly soluble in water
• SG of .1785, second lightest gas to H
• Inert (unreactive)- does not support life
• must always be at least 20 O2 80 He mix, i.e.
  Heliox
• He low density decreases WOB
• Rarely used in severe airway obstruction

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Nitrous Oxide (N2O)

• Colorless
• Slightly sweet odor test
• Supports combustion
• Beneficial for Anasthetic affect
• CNS depressant
• Does not support life
• Must be at least 80/20 N2O/O2 mix
• Used with other anesthetic agents b/c of its
  toxicity at high levels, gt25ppm
• Full anesthetic effect at high, gt25ppm,
  concentrations.

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Nitric Oxide (NO)

• colorless
• non-flammable
• supports combustion
• toxic
• FDA approved
• Term/near term neonates w/ hypoxic respiratory
  failure, PHTxN
• To be used before extracorpeal membrane oxygenax
  (ECMO)
• Contra-indicated for premies

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Nitric Oxide (NO)

• NO air Nitrogen Dioxide NO2
• NO2 is a strong pulmonary irritant, pneumonitis
• Can cause fatal pulmonary edema
• Byproduct of the metabolism of NO is
  Met-hemoglobin
• High levels of methemoglobin reduces the amount
  of available Hgb available for oxygen uptake,
  resulting in tissue hypoxia

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Storage of Medical Gases

• Gas Cylinders
• Markings
• Front
• DOT or ICC (interstate commerce commix)
  classificax
• 3A Carbon Steel
• 3AA Steel Alloy, stronger
• filling Pressure (psi)
• Owners mark
• Class of Tank, i.e. size
• E H are most common

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Storage of Medical Gases

• Gas Cylinders
• Markings
• Back
• Material method of manufacture
• EE elastic expansion
• Retesting Dates codes
• indicates ten year retest
• indicates tank is good for 10 fill above
  filling P.
• Hydrostatic Testing

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Storage of Medical Gases

• Gas Cylinders
• Color Codes Labels T 37-2 united states, KNOW
  These
• Color codes are not standardized internationally
  therefore the labels must always be verified
  before administrax
• O2 green
• Air - Yellow
• NO Teal - Nitric
• N2O Blue - Nitrous
• CO2 gray

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Storage of Medical Gases

• Gas Cylinders
• Sizes content
• Small (xport anesthesia)
• E AA
• Post Valve connector
• Large
• F-H/K
• Threaded Valve connector

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Storage of Medical Gases

• Cylinder Safety Relief Valves
• Frangible Disk ruptures
• Fusible Plug
• Melts
• Small Cylinders
• Spring Loaded
• Opens
• Large cylinders

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Storage of Medical Gases

• Filling or Charging Cylinders
• Compressed Gases
• Filled to service P _at_ 70F or 10 if approved
• Service P is stamped on cylinder shoulder
• Liquified Gases
• For Gases with Critical Temps above Room Temp
• Will store as a liquid
• Filled using ration of liquid stored density to
  water density
• CO2 density is 68 of water, so it fills the
  cylinder 68 of the weight of water that cylinder
  can hold
• Cryongenic to be discussed later

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Storage of Medical Gases

• Measuring Cylinder Contents
• Compressed Gas Cylinders
• _at_ constant T, V is directly proportional to P
• If 2200psig is 100 then 550psig is 25 full

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Storage of Medical Gases

• Measuring cylinders
• Liquid Gas Cylinders
• Gauge measures vapor P, thus
• As long as there is liquid present, vapor
  pressure remains constant at a constant T
• Once liquid is fully vaporized, gauge measures
  content
• When empty or
• When temp is allowed to rise above crit temp
• As temp increases more liquid vaporizes gauge
  reads higher P, above crit temp all liquid is
  vapor gauge will read accurately.
• Weighing is the only accurate method to check
  contents of liquid in a cylinder

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Gas Cylinder

Liquid Cylinder
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Storage of Medical Gases

• Estimating Duration of Gas Cylinder
• Dependant on
• Flow
• Cylinder size
• Cylinder Pressure
• Duration of flow is directly proportional to the
  contents (pressure) inversely proportional to
  flow
• Cylinder factors T37-5
• Represent the volume of gas leaving a cylinder
  per psi
• Know O2 cylinder factors for E, G, H
• E .28 or 3
• G 2.4 or 2.5
• H 3.14 or 3, or Pi

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Storage of Medical Gases

• Estimating Durax
• Duraton in min (Psi)(cylinder factor) / Flow
  in L/m
• 154 min (2200)(.28) / 4L/m O2 in an E
  cylinder
• 165 min (2200)(.3) / 4L/m
• Rule of 10
• A full E cylinder _at_ 10 L/m will run for 1 hour, _at_
  5L/m for 2hours, 2.5l/m for 4 hours
• A full H cylinder will last 10 times longer than
  an E

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Storage of Medical Gases

• Estimating Duration of Liquid Cylinder
• Weight
• 1L liquid O2 weighs 2.5lbs
• 1L liquid O2 860 L O2 gas
• Gas in cylinder (L) liquid O2 weight x 860 /
  2.5 lb/L
• Duration of Gas (min) Gas in cylinder (L) /
  Flow (L/m)

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Storage of Medical Gases

• Gas Cylinder Safety
• Storage
• Rack em
• Away from combustibles heat
• No smoking signs, oxidizing agents sign
• Separate flammable and combustable supporting
  gases
• Keep cap in place when not in use
• Separate or at least designate full empty
  containers
• Liquid containers must be in well vented, cool
  areas
• Liquid O2 tanks constantly vent gas to prevent
  pressure build ups since at room temp liquid O2
  is constantly vaporizing

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Storage of Medical Gases

• Gas Cylinder Safety
• Xport
• Use carts cylinder caps
• Protect from hitting other objects
• Use
• Secure cylinders
• No smoking signs
• Do not use flammable materials near them,
  especially oil or grease
• crack cylinder before use
• ASSS for H
• PISS for E

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Storage of Medical Gases

• Bulk O2
• Required by large acute facilities
• gt20,000 cubic ft of gas
• Liquid storage is most common
• Central storage with piping t/o facility to quick
  connects
• More affordable over the long run
• Less prone to interruption
• Safer than cylinders
• Central pressure regulation rather than at each
  connect
• Low pressure system

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Storage of Medical Gases

• Gas Supply systems
• Cylinder Manifold or alternating supply
• Cylinder supply with reserve
• Bulk gas with reserve

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Storage of Medical Gases

• Bulk O2 Safety
• Reserves are mandatory to supply the daily
  average hospital use of O2
• RTs must be ready to provide tanks to vent
  high O2 patients

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Distribux Regulax of Med Gas

• Central Piping Systems
• Primary function
• Must be piped to pt room
• Must be reduced to 50psi, standard working P
• May include air, O2, vacuum specialty gases
• Pt safety is priority regardless of delivery
  method
• RTs must be familiar with these
  systems/connections
• Safety connectors are used to ensure
  misconnections do not occur
• Zone valves allow shut off to specific areas for
  maintenance/fire

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Central Supply

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Zone Valves

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Distribux Regulax of Med Gas

• Safety Indexed Connector Systems
• ASSS American Standard Safety System
• Large cylinders (high P)
• Uses variation In threads for each gas

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Distribux Regulax of Med Gas

• Safety Indexed Connector Systems
• PISS Pin Index Safety System
• Small cylinders (high P)
• Pin-holes vary for each gas type

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Distribux Regulax of Med Gas

• Safety Indexed Connector Systems
• DISS Diameter Index Safety System F37-16
• Low P outlets
• Usually for
• Inlets of flowmeters, blenders, vents other
  Pneumatics
• Outlet valves
• P reducing valves
• Different sizes for different gases

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DISS

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Distribux Regulax of Med Gas

• Safety Indexed Connector Systems
• QC Quick Connect System F37-17
• Station outlets, (Low P)
• Unique shaped connectors for each gas

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Distribux Regulax of Med Gas

• Regulating Gas Pressure Flow
• P Flow must be regulated for use
• Cylinder gases exert to much P to use safely
• Reducing Valve
• Reduces gas Press to 50Psi
• Flowmeter
• Controls gas flow
• Regulator
• Reduces P controls flow

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Connecxs

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Distribux Regulax of Med Gas

• High-Pressure Reducing Valves
• Preset
• Inlet Valve
• Inlet P gauge
• Hi P chamber
• Ambient P chamber
• Flexible diaphragm
• Calibrated spring
• Provides constant adjustment
• Keeps P at 50psi
• Valve stem
• Hith P inlet
• Gas outlet
• Safety vent 200psi

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Distribux Regulax of Med Gas

• Adjustable F37-20
• Just like Preset, but hand control allows spring
  tenx adjustment b/w 0-100psi
• Multi-Stage
• Essentially two single stage valves connected in
  series
• Reduces P in two increments
• Provide very constant P smooth Flow
• Good for research
• Expensive for hospital work

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Distribux Regulax of Med Gas

• Proper Use B37-1
• Secure cylinder
• Remove cap
• Crack cylinder to remove debris
• Inspect for dirt/damge, check label
• Tighten regulator on to tank
• Slowly open to pressurize gauge

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Distribux Regulax of Med Gas

• Low-Pressure Gas Flowmeters
• Medical gas is a drug, prescribed in L/m
• Gas mixing delivery devices require expert
  knowledge
• Flow Restrictor F37-21
• Simplest least expensive
• Calibrated to deliver a set flow, psi of 50
  constant
• Fixed orifice
• Non-gravity dependant
• 0.5 l/m 3l/m increments are common
• Common in HO2

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Distribux Regulax of Med Gas

• Low P gas flowmeters
• Bourdon Gauge F37-22,23
• Controls flow regulates P
• Fixed orifice, variable P
• Gauge senses upstream P but is calibrated to
  indicate flow
• Increasing P increases flow
• Non-gravity dependant
• Ideal for xport
• Disadvantage
• Backpressure downstream from orifice will reduce
  flow delivered, however b./c gauge actually
  measures upstream Pressure, gauge will indicate
  an erroneously High reading of flow. F37-24

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Bourdon Gauge

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Distribux Regulax of Med Gas

• Low P gas flowmeters
• Thorpe Tube F37-25,26,27
• Always attached to a reducing valve or low P wall
  outlet
• Constant P
• Variable orifice
• Thorpe tube is increasingly widening from bottom
  to top.
• Gas flow pushes up float in tube against gravity,
  ATM P
• Measures flow only, not P like bourdon gauge
• Compensated V. Noncompensated

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Thorpe tube Flowmeter

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Distribux Regulax of Med Gas

• Thorpe Tube
• Non-Compensated
• Downstream P raises the pressure acting downward
  on the float to hyperbaric P, forcing the float
  down at a given flow.
• Scale of tube is calibrated to PB
• Meaning that a reading of 6l/m is actually
  providing a higher flowrate to the patient.
• Needle valve is proximal to Thorpe tube so
  Backpressure acts on entire Thorpe tube
• Some vents anesthesia machines use these

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Uncompensated

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Distribux Regulax of Med Gas

• Thorpe Tube
• Compensated
• Scale calibrated to 50psi instead of PB
• Needle valve is distal to Thorpe tube, entire
  tube operates at 50psi
• Float jumps when connected to wall connect b/c
  the tube is being pressureized
• Ideal for most clinical situations
• Gravity dependant
• Poor for xport

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Compensated
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Color Codes for Medical Gases

• Air Yellow, black, white
• Oxygen Green and White
• Carbon dioxide gray
• CO2/O2 gray and green
• Helium brown
• Nitrogen black
• Nitrous oxide light blue

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Distribux Regulax of Med Gas
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Distribux Regulax of Med Gas
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Distribux Regulax of Med Gas
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Distribux Regulax of Med Gas
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Safety Systems

• ASI large cylinders
• PISS small cylinders
• DISS wall units-press less then 200 psi

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Cylinder duration calculations

• E 0.28
• G 2.41
• H 3.14
• Cylinder pressure (psi) X cylinder factor
• L/Min

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Gay-Lussacs Law bulk liquid system.
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