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					    Oxygen Masks
Types, Advantages and
    Disadvantages

   Ahmet Ilvan, M.D.



                        1
The relationship among minute
ventilation, O2 flow rate and FiO2
                                              Patient with COPD

                          In respiratory distress       After relief of respiratory
                                                        distress
Ventilatory minute        30 L/min                      7.5 L/min
volume (respiratory       (40 breaths/min x 750         (15 breaths x 500
rate x tidal volume)      ml/breath)                    ml/breath)
Oxygen flow rate          2 L/min                       2 L/min
                          2 L/min of 100% O2            2 L/min of 100% O2
                          +                             +
                          28 L/min of air drawn in to   5.5 L/min of air drawn in
                          the mask (21% O2)             to the mask (21% O2)
                          =                             =
Calculation of inspired   30 L/min minute               7.5 L/min minute
oxygen (FiO2)             ventilation                   ventilation
                          Thus                          Thus
                          FiO2=                         FiO2=
                          (1.0x2) + 0.21x28) / 30       (1.0x2) + 0.21x5.5) / 7.5
                          = 0.26 (26%)                  = 0.42 (42%)
                                                                                                  2
                                                           NT Bateman, RM Leac.h BMJ 1998; 317:798-801
Oxygen delivery devices
• Oxygen delivery devices in the acute
  setting
• Long-term oxygen delivery devices




                                         3
Oxygen delivery systems in the
acute setting
• Low-flow oxygen delivery devices
• High-flow oxygen delivery devices




                                      4
The working methods of low and
high flow devices
                      High flow oxygen masks
                      provide entire ventilatory
                      requirement using a Venturi
                      valve. The port size of the
                      valve ensures the correct
                      proportion of oxygen and
                      entrained air are mixed to
                      obtain a fixed oxygen
                      consantration . Low flow
                      oxygen masks do not
                      provide the entire
                      ventilatory requirement. Air
                      is drawn in through the
                      loose fitting mask to
                      supplement the oxygen flow
                      rate.

                                                              5
                             NT Bateman, RM Leach. BMJ 1998; 317:798-801
Low-flow oxygen delivery devices
• These systems provide a fraction of patient’s minute
  ventilatory requirement as a pure oxygen; the remainder
  of ventilatory requirement is fullfilled by addition of room
  air.
• There may be marked variation in the fraction of inspired
  especially in patients with abnormal or variable
  ventilation pattern. FiO2 increases in shallow breathing,
  decreases hyperventilation.
• Low-flow oxygen delivery devices should not be used in
  patients with chronic carbon dioxide retention (such as
  COPD).
• These devices are used in patients with type I respiratory
  failure (pulmonary edema, embolism)

                                                             6
 Low-flow oxygen delivery devices
• Nasal cannula
• Simple masks
  – Simple face mask
  – Face tent
  – Tracheostomy mask
• Masks with reservoir
  – Partial nonrebreathing mask
  – True nonrebreathing mask
                                    7
High-flow oxygen delivery devices
 • Venturi mask
 • Reservoir nebulizers




                                    8
Long-term oxygen delivery systems

• Nasal cannula
• Transtracheal catheters
• Oxygen conserving systems
  – Reservoir nasal cannula
  – Electronic demand devices




                                9
Nasal cannula




                10
Nasal cannulae
• Flow rate
   – 1-6 L/min
• FiO2
   – 22-44%
   – factors
       • Inspiratory flow and pattern
       • Respiratory rate, exhalation time
       • O2 flow rate
       • Mouth breathing
   – Typically; FiO2 increases 0.03-0.04 for each l/min
   – Maksimum FiO2 0.44
       • 1 L = 0.24
       • 2 L = 0.28
       • 3 L = 0.32
       • 4 L = 0.36
       • 5 L = 0.40
       • 6 L = 0.44

                                                          11
Nasal cannulae
• Advantages
  – Safe and simple to apply.
  – Comfortable/easily tolerated.
  – Allows movement; eating, sleeping and talking.
• Disanvantages
  –   Will not deliver oxygen concentrations higher than 44%.
  –   Can not be used in complete nasal obstruction.
  –   May cause headaches and skin irritation.
  –   Dislodges easily.
• Administration guidelines
  – Maximum flow is 5-6 L/min. Change to another O2 device if
    patient requires >6 L/min.
  – Humidifier bottle unnecessary; exception may be used for
    patient comfort for liter flows >4 L/min .


                                                                12
Simple face mask




                   13
Simple face mask
 • Flow rate
   – 6-12 L/min
 • FiO2
   – 35-55%
 • Advantages
   – Easy to setup and apply
   – Often found at the head of the bed in emergency
     areas.




                                                       14
Simple face mask
• Disanvantages
  – Nonspecific FiO2 (dependant on patients inspiratory
    flows).
  – Maximum FiO2 estimated at 0.55.
  – Not intended for long term use.
  – interferes with eating/talking.
  – May cause skin irritation.
• Administration guidelines
  – A minimum of 5 L/min is required for all masks to
    flush expired carbon dioxide and prevent rebreathing
    of CO2.
  – Do not use humidifier bottle.


                                                          15
Face tent
• Designed for patients
  who can not wear a
  mask or nasal prongs
  (eg. facial surgery or
  trauma)
• Bulky and
  cumbersome.
• Difficult to administer
  a specific FiO2

                            16
Tracheostomy mask
• Designed for patients
  with a tracheostomy

• require frequent
  cleaning/replacement
  if patient is coughing
  up sputum.



                           17
 Reservoir masks
(Partial nonrebreathing mask)




                                18
Reservoir masks (Partial nonrebreathing mask)
• No exhalation valve to        • Flow rate
  prevent CO2 into reservoir.     – 6-10 L/dk
• Flow rate>8 L/min; Oxygen     • FiO2
  reservoir kept full.            – 0.60-0.85
• initial vs terminal expired        • 6 L = 0.60
                                     • 7 L = 0.70
  gas: inital exhaled gas
                                     • 8 L = 0.80
  (from anatomic deadspace,          • 9 L = 0.80+
  therefore with no CO2)             • 10 L = 0.80+
  goes into reservoir while
  terminal gas is exhaled.
  This should minimize
  rebreathing.
                                                  19
Reservoir masks (Partial nonrebreathing mask)
• Advantages
  – Fast and easy to set up
• Disadvantages
  – FiO2 is extremely variable. While theoretically capable
    of delivering an FiO2 of 1.00, realistically it is more
    likely between .60 and .85.
  – interferes with eating/talking
  – may cause skin irritation.
  – This is not a long term usage mask.
• Administration guidelines
  – Reservoir bag must always remain inflated. If
    deflation occurs the oxygen flow may be too low.
                                                         20
 Reservoir masks
(True nonrebreathing mask)




                             21
Reservoir masks (True nonrebreathing mask)
 • There are unidirectional valves on each side of
   mask and between mask and reservoir.
 • These valves prevents expired gas going into
   reservoir and CO2 rebreathing, and inspiration of
   room air.
 • Flow rate
   – 4-15 L/min
 • FiO2
   – 60-100%
 • Highest FiO2 possible
   – 10 L/min = 0.80+
   – 15 L/min= 0.90+
                                                  22
Reservoir masks (True nonrebreathing mask)
 • Advantages
   – Fast and easy to set up.
 • Disadvantages
   – FiO2 is extremely variable. While theoretically capable
     of delivering an FiO2 of 1.00, realistically it is more
     likely between .60 and .95.
   – Interferes with eating/talking.
   – May cause skin irritation.
 • Watch for
   – Reservoir bag must always remain inflated. If deflation
     occurs the oxygen flow may be too low.
   – This is not a long term usage mask.


                                                         23
Venturi mask




               24
 How a Venturi mask works
The Bernoulli effect (was
  described in 1778):             Mixed gas

  fluid velocity increases
  at a constriction.

Mathematically this can       R
                              o
                              o
 be written:                  m
                              a
                              i
  1/2*v2+p = constant         r



  where * is the density, v
  is the velocity, and p is       O2 100%
  the pressure.                               25
Venturi mask
• High-flow devices with no valves or reservoirs
• The operation of Venturi mask based on Venturi
  modification of the Bernoulli principle of fluid
  physics for gaseous jet-mixing.
• A Venturi tube is connected to the mask.
• Flow rate
  – Adjustable.
  – FiO2 can be adjusted to 2-12 L/min by changing
    Venturi tube.
• FiO2
  – 24-50%



                                                     26
Venturi mask
• Advantages
  – It can be delivered consant O2 independent from patient’s
    breathing.
  – It doesn’t cause dryness on mucosal membranes.
  – Quiet.
• Disadvantages
  – FiO2 only available according to mask adapters (.24, .28, .31, .35,
    .40 and .50).
  – interferes with eating/talking.
  – This is not a long term usage mask.
  – May cause skin irritation.
• Usage advices
  – No need humidification.
  – Colour coded adaptors are not universal. Different companies
    use different colours.


                                                                    27
                 Venturi mask
 Guide to colours of Venturi
             valves

Venturi    Flow     Oxygen
  valve      rate   delivered

colour    (L/min)    (%)

Blue        2         24

White       4         28

Yellow      6         35

Red         8         40
Green       12        50

                                28
Large volume nebulisers
• They can be used with mask, tracheostomy
  catheter and face tent.
• Flow rate
  – 10-15 L/min.
• FiO2
  – Variable, 30-100%




                                             29
Large volume nebulisers
• Advantages
  – It can be made high humidification
  – It is suitable in patients who had
    tracheostomy, entubated, and solidified
    secretion.
• Disadvantages
  – Can be condensation in system
• Usage advices
  – It should be observed for overhidration,
    pulmonary edema.
  – FiO2 can be adjusted by changing the O2 flow
    rate which system connected.
                                               30
Long-term oxygen delivery systems

  • Nasal cannula
  • Transtrcheal catheters
  • Oxygen conserving systems
    – Reservoir nasal cannula
    – Electronic demand devices




                                  31
Mike Cannula




               32
Transtracheal catheter
• Transtracheal O2 is used in
  patients who don’t want to
  wear cannulea and mask in
  their faces because of some
  cosmetic reasons by
  entering into 2nd or 3rd
  tracheal interspaces with
  fine percutan catheter.
• It was reported that 37-58%
  lower O2 is consumed by
  transtracheal catheter
  comparing with continuous
  nasal O2 system.
• Flow rate 0.25-4 L/dk
• FiO2 22-45%
                                33
Transtracheal catheter




                         34
Transtracheal catheter
• Advantages
   – Improved comfort and convenience
   – Lower oxygen requirements
   – Increased mobility
   – Greater exercise capacity
   – True 24 hour per day oxygen therapy
   – Improved sense of smell, taste and appetite
• Disadvantages
   – Bronchospasm, wheezing (in asthmatics)
   – Cough
   – Emphysema
   – Tracheal chondritis
   – Small growths of scar tissue around the tract
     opening
                                                     35
OxyArm cannula
• The OxyArm is designed
  as to alternative the
  oxygen face mask and
  nasal cannula.
• accommodates both nose
  and mouth breathing.
• allows for talking, eating
  and drinking.
• It will not irritate the
  sinuses.
• It may increase
  compliance and overall
  effectiveness of oxygen
  therapy.
• Comfortable.

                               36
Reservoir cannulas (Oxymizer)
• Oxygen reservoir cannulas
  are developed to decrease
  O2 expenditure.
• Reservoir cannulas stores
  O2 in expirium and then       Mustache

  gives to patient in the
  beginning of inspirium.
• There are two cannulas like
  mustacha and pendant.
• Flow rate 0.25-4 L/dk
• FiO2 22-35%                   Pendant
                                           37
Electronic demand devices
• Electronic devices that sense the
  beginning of a breath and deliver a pulse
  of oxygen are also available.
• They are complicated, expensive, and
  have a risk for mechanical failure.
• Newer units have a continuous flow
  bypass switch that allows delivery of
  oxygen if the battery has run down.
                                              38
Electronic OCD



  REACT Oxygen Conserver           The PD 4000 Oxygen
  by Crammer Decker                Conserver by Devilbiss




 The SAGE S.M.A.R.T Therapeutic   DeVilbiss® PD1000 Compact
                                                                39
 Pulse Dose Conserver by Chad     Pneumatic Conserving Device
Which mask for which patient?
Patient                                                    Simple face
  With normal vital signs--for example, postoperative,       mask
  slightly low oxygen saturations, long term treatment     Nasal
  with oxygen at home                                        cannulas


Higher concentrations of oxygen are required and
   controlled oxygen is not necessary--for example,      Simple face
   severe asthma, acute left ventricular failure,          mask
   pneumonia, trauma, or severe sepsis.                  Masks with a
(Masks should always be set to a minimum of 5 l/min       reservoir
   because significant rebreathing of CO2 can occur when bag
   exhaled air is not adequately flushed from the mask)

Controlled treatment with oxygen required in people with   Venturi
  COPD acute attack.                                        mask
                                                                     40

				
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posted:12/13/2012
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