Oxygen Delivery Systems
Do not meet the patients inspiratory
flow demands.
Normal inspiratory flow rate is 25 to 30
L/min
Additional flow comes from RA
q Nasal Cannula and Nasal Catheters
Delivers 24 to 44% oxygen at 1 to 6
L/min
1 = 24
2 = 28
3 = 32
4 = 36
5 = 40
6 = 44
·
Nasal Catheters
measured from nose to ear, lubricated
and inserted to just above the uvula
**deep insertion can cause air swallowing
and gastric distension
**must be repositioned every 8 hours to
prevent breakdown
·
Transtracheal Catheters
Delivers low flow rates (1 to 3 L/min)
directly to the trachea through a small incision
Requires less oxygen (lower flows)
because the upper airway deadspace is
bypassed
**Can develop infection and irritation at site
and there is a risk of accidental removal
**If pt becomes SOB or has increased
**Flush with saline**
**Cleaning Rod **reposition
·
Cannulas
better tolerated
may be humidified but often not if run @
less than 5 L/min
there are two types of O2-conserving
cannulas
-Nasal reservoir
reservoir just below the nose stores ~
20 mL of O2
allows for lower flows because of
increase O2 delivery
-Pendent reservoir
pendent stores O2
must exhale through nose
**HFNC - 6-15lpm
·
Simple masks
Delivers 35 to 55 % O2 at flows of 5 to
12 L/min
**Must never be used at flows less than 5
L/min to prevent rebreathing of CO2
·
Partial Rebreathing Masks
Delivers 35 to 60 % O2 at flow rates of 8
to 15 L/min
**Flow rate must be sufficient to keep bag
1/3 to 1/2 inflated at all times
·
Non-rebreathing Mask
Delivers 60 to 90% O2 at flow rates of 8
to 15 L/min (NBRC says 100%)
**Flow rate must be sufficient to keep bag
1/3 to 1/2 inflated at all times
Is equipped with a one-way valve that
does not allow exhaled gas into the reservoir
One way valves are located on both
expiratory ports of the mask to prevent
RA entrainment
The percentage of O2 delivered by a low flow
device is variable because RA is entrained.
FiO2 will vary depending on the patients RR,
pattern and VT
Patients who have variable ventilatory
patterns, RR >25 and VT that vary outside of
300-770mL, should not use a low flow system
High
Flow Oxygen Systems
·
Methods for setting up high flow oxygen
1) air
entrainment mask
2) mechanical
aerosol systems
3) Gas Injection Nebulizer- need high
flow flowmeters
4) High FiO2
5) Blender and titration system
High flow O2 systems provide all of the
inspiratory flow required by the patient at
consistent FiO2s
These devices are normally attached to
nebulizers
(Venti-mask may or may not be)
·
Venturi Mask or air-entrainment
masks
provide FiO2’s from 24 to 50%
Increasing flow will not alter FiO2
(precise)
The size of the entrainment port
determines FiO2
The larger the port, the more RA
entrained, the lower the FiO2
·
Aerosol Mask
Delivers 21-100% FiO2 depending on
nebulizer setting
Flow rates of 8 to 15 L/min
On 100% the device will probably not
meet flow demands.(>60%) (No air entrained so
flow = flowmeter setting)
·
Face Tent
21% to 40% depending on nebulizer
setting
Flow rates of 8 to 15 L/min
Used mainly for patients who can not
tolerate a mask
·
T-Piece (T-tube,
21-100% depending on nebulizer setting
Flow rates of 8 to 15 L/min
Used on intubated or trached patients
Allows use 50 mL of reservoir tubing to
maintain FiO2 Adequate flow is demonstrated by
visible mist out of the reservoir
·
Trach Mask
35-60% O2 depending on nebulizer
setting
Flow rates of 10 to 15 L/min
**Adequate flow shown by mist flowing
out the exhalation port at all times
·
Oxygen Tent
21 -50% at flow rates of 10 to 15 L/min
Used mainly on children with croup or
pneumonia
Problem with leakage
Fire hazard
·
Important Points
**High FiO2’s (>.60) may not meet the
patient’s inspiratory flow demands
To insure adequate flow with stable
FiO2’s, a special made high flow device
should be used or two flowmeters set
up to provide at least 40 L/min total flow
**A restriction, such as a kink, or water in
the tubing, causes back-pressure into
the nebulizer. This decreases the
amount of RA entrained and INCREASES the delivered FiO2.
**Increasing flow on a high flow device
will not increase FiO2, only total flow
·
Head box-
small, clear plastic enclosures over infant’s head or head and
upper torso
Head boxes allow for a higher oxygen
concentration and more accessibility to patient without disturbing oxygen
delivery.
. Best not to entrain room air into head box because of noise and microorganism introduction (Blender)
·
air: oxygen entrainment ratios:
.60 1:1
.50 1.7:1
.40 3:1
.35 5:1
.30 8:1
BiPAP
BiPAP stands for Bilevel Positive Airway Pressure.
Bilevel means that
the pressure varies during each breath cycle.
Inspiration can be triggered by flow or
time and is cycled by time or flow.
·
IPAP = inspiratory positive airway pressure 8 to 20 cm H2O
·
EPAP = expiratory positive airway pressure 2 to 10 cm H2O
The
BiPAP aids oxygenation and ventilation in cases of
sleep apnea or ventilatory muscle fatigue.
It
has also been applied to prevent the more invasive procedures of intubation or
tracheostomy.
Humidifiers
Low-Flow Humidifiers
(unheated)
·
Pass-Over
Humidifiers
Gas passes
over the surface of H20, picking up moisture
Because
bubblers are water reservoir, they can support the growth of Pseudomonas aeruginosa.
Improperly
handled humidifiers have been linked to nosocomial
respiratory infections with this pathogen
·
High Flow
Humidifiers (heated)
-Heated Pass-over
directs gas over a
reservoir of heated water.
-Diffuser Cascade
A more
efficient design of the low flow diffusion (bubbler) humidifier.
Besides being heated, the area for gas
water interface is increased by use of large diffusion tower. Temp, surface,
contact time effect amt
-Bubble through wick
utilize a paper/cloth wick through which the mainstream flow
must pass.
Water levels of all humidifiers
should be maintained as marked to ensure maximum humidity output.
Condensation will occur in the
tubing of heated humidifiers. This water should be discarded in a trash contain
and never returned into the humidifier.
Inspired gas temperature should
be monitored continuously with an inline thermometer when using heated
humidifiers.
The thermometer should be as
close to the patient wye as possible.
Warm, moist areas such as those
within heated humidifiers are breeding grounds for microorganisms (especially Pseumomonas).
The humidifier should be changed
every 24 hours.
-Heat moisture exchangers (HME, artificial nose).
Exhaled heat and moisture are collected
and made available to warm and humidity the following inspiration. Change
Daily**
Types of Nebulizers
·
Jet (Mechanical)
Uses a high pressure gas stream (
--50% of output is in the 0.5-3 micron
range
·
Babington
Nebulizer
Uses the principle of a jet stream of
gas being directed through a thin film of continually flowing liquid spread
across a rounded surface
**Important
Points on Nebulizers
--Heated
nebulizers are the greatest source of contaminated moisture to the patient.
--Should
be changes every 12 to 24 hours
--Jet
and capillary tubes should be kept free of build-up to provide adequate mist and allow
fluid to be drawn up the tube adequately.
--Water
level must be maintained to assure optimal aerosol output
--Water
in the aerosol tubing will increase the % oxygen delivered to the patient
Manual Resuscitators
Used
for:
Rescue
breathing
Hyperinflation
To
transport patients who require ventilation
Ideal
stroke volumes: Adult—800mL avg.
Infant—200mL
·
Safety devices
-Non-rebreathing valve
-Universal
adapter 22-mm OD and a 15-mm ID
-Pressure
relief device (25cmH20)
·
Self inflating bags
Can be used without gas flow
Usually reusable but disposable are
available
Require
reservoir to deliver 100% oxygen
·
Flow-inflating bags
Depends on a gas source
Must have a tight seal to inflate
Uses a flow-control valve to regulate
pressure inflation
To achieve the highest FiO2
levels:
Always use a reservoir
attachment, if available
Use the highest flow available
(10-15 l/min)
Slower rates with long bag refill
time, allows for higher FiO2’s to be delivered
Smaller volumes also deliver
greater FiO2’s
Hazards:
Leaks because of inadequate seals
or leaky cuffs
Equipment malfunctions—sticky
valves, etc
Poor ventilation technique
**Troubleshooting Manual Recesitators
If the valve jams at high
flows, reduce the flow to between 8-15 L/min. If this does not relieve the
problem, get another bag.
Accumulation of secretions or
vomit in the valve may result in sticking with diversion through the pop-off.
Cleaning the valve should resolve the problem in permanent or disposable bags.
·
Four standard criteria for initiating mechanical ventilation
apnea
acute ventilatory
failure
impending ventilatory
failure
hypoxemic respiratory
failure
Both volume-cycled and pressure-cycled volume
delivery modes.
Many
older transport ventilators may operate on a time-cycled mode.
·
Pressure-cycled
A peak inspiratory pressure (PIP) is
applied and the pressure difference between the ventilator and the lungs
results in inflation until the peak pressure is attained, and passive
exhalation follows.
-Pressures are constant - volumes
vary
The delivered volume with each
respiration is dependent on the pulmonary and thoracic compliance as well as
airway resistance
This requires close monitoring
and may limit the usefulness of this mode in emergency department patients.
·
Volume-Cycled
-Inhalation proceeds until a set tidal
volume (TV) is delivered and is followed by passive exhalation.
-Since the volume-cycled mode ensures a constant minute ventilation, it is a common choice as an
initial ventilatory mode.
-A feature of this mode is that gas is
delivered with a constant inspiratory flow pattern, resulting in peak pressures
applied to the airways higher than that required for lung distension (plateau
pressure).
-Volume delivered is constant - pressures
vary
Ti + Te = TCT
TCT = 60/BR
BR= 60/TCT
Vt = flow rate x
Ti / 60 sec.
flow rate = Vt / Ti
Ti = Vt x 60 sec /
flow
Excessive airway pressures may be
generated, resulting in barotrauma.
Close monitoring and use of
pressure limits are helpful in avoiding this problem.
·
High Frequency Ventilation
Use of supraphysiologic
ventilatory rates above 60 rpm
Use of tidal volume smaller than the
anatomic dead space
-Types of HFV
High
frequency positive pressure ventilation (HFPPV) - refers to the delivery
of small tidal volumes through an insufflation
catheter or endotracheal tube with circuitry having a minimal compressible
volume.
The
characteristic rate is 60 - 100 cycles per minute with inspiration taking 20%
to 30% of the total cycle time.
VT
used are between 3 and 5 ml/kg
High Frequency Jet Ventilation
During
High Frequency Jet Ventilation (HFJV), gas is propelled into the lungs at a
very high velocity through a jet catheter
Rates
of 100-600
Can
be used in conjunction with CMV
High Frequency Oscillatory
Ventilation
Oscillating device forces small
impulses of gas into and out of the airway
Exhalation is said to be active in
high-frequency oscillation
Can deliver 1 to 60 Hz.
I
Hz equals 60 cycles
5
Hz = ~300 bpm
VT
less than VD
·
Manipulate Blood Gases with High Frequency:
A.HFPPV-
> to decrease PaCO2:
- decrease frequency with same Ti
- increase Ti with same frequency
B.HFJV-
>To
decrease PaCO2
- dec.
frequency with same PIP and Ti
- inc. driving
pressure with same frequency and Ti
- increase
delta P = increase ventilation
- increase MAP = increased oxygenation
Artificial Airways
·
Oropharyngeal Airway (bite block)
Used on unconscious patients to prevent the tongue
from obstruction the airway
Two
main types
-Berman
is hard plastic with an “I-beam” design
-Guedel is hollow type that has opening in the middle
**Should never be taped in place,
must be easily removable in cause of vomiting
**Gagging or fighting
Improper insertion causing tongue
to block the airway
·
Nasopharyngeal Airway (trumpets)
maintains
a patent airway by pushing the tongue forward off the posterior portion of the
oropharynx
better
tolerated by semi-conscious or conscious patients
used to allow
nasotracheal suctioning with decreased trauma
make sure the patient
has no history of broken nose, deviated septum or other nasal obstructions
make sure water
soluble or water based lubricant is used to minimize trauma to the mucosa
·
ET Tubes
Indications
for ET tubes:
Patent airway (Upper airway
obstruction)
Protect the airway
Facilitate suctioning
To assist in manual or mechanical
ventilation
Hazards of ET tubes:
Infection
Trauma
vocal cord damage
laryngeal or trachea
edema/damage
mucosal damage
Mechanical problems
tube occlusion
R mainstem
intubation (>25 cm deep-orally)
·
Tube size
adult male 8 mm to 9 mm tube
adult female 7 mm to 8 mm tube
Endotracheal
tubes (ETT) are sized by either the internal diameter (2.5 to 10 mm) or the
external diameter with sizes 32-42 French (Fr).
·
Laryngoscope
The must be held with the left hand.
(Good for us lefties)
Most adults require a (curved) Macintosh
# 3 or 4 blade or a straight Miller #3
·
Tracheostomy Tubes
Preferred for long-term
When upper airway obstruction prevents
intubation
ET tube is removed only as trach
tube is ready to be inserted.
Easier
to stabilize, suction and tolerate
Inner Cannulas - Fewer hazards and minimal airway
resistance
Obturator - is used for insertion into stoma
Cuff - (if present) is
inflated
A Tracheal Button - is a rigid
cannula placed stoma after removal of a trach tube. *For Stoma only Pt.
It
is generally kept closed during the day to be unobtrusive, and opened at night
to eliminate sleep apnea.
·
Suctioning removes air as well as secretions from the lungs.
·
Hypoxemia can be minimized by hyperoxygenating
the patient 1 to 2 minutes
·
Usually done with 100% if possible (NRB)
·
Patient should be hyperoxygenated
between suction attempts
·
Suctioning should take less than 15 seconds per pass
Other
types of catheters
Yankauer
used to suction oropharynx
Coude (directional
tip) used to guide catheter into the left mainstem
·
Vacuum Systems
Central (wall) vacuum systems connect
to a vacuum regulator via a quick connect or DISS connector
**Infants 60-80 **Peds 80-100 **Adults 100-140
Most
Chrome molybdenum *2200 psig
·
“H” cylinder holds 244 cu ft (6900 L)
·
“E” cylinder holds
22 cu ft (622 L)
·
(There are 28.3 L in 1 cu ft.)
·
Cylinder color codes
oxygen- green or
white(international)
nitrogen- black cyclopropane- orange
helium- brown heliox- brown and green
air-yellow, black and
white, black and green
carbon dioxide- gray
carbogen- gray and
green
ethylene- red
nitrous oxide- light
blue
·
Valves on cylinders allow connection to
only one type of gas regulator:
-American Standard Safety System
(ASSS) for high pressure connections on large cylinders
Pin Index Safety System
(PISS) for high pressure connection on small cylinder
Diameter Index Safety
System (DISS) for low pressure (<200psi)
·
Cylinder duration:
E cylinder: #
of minutes remaining = psig x 0.28
lpm
H cylinder: #
of minutes remaining= psig x 3.14
lpm
·
Safety Relief Device
--A frangible disk which breaks to release
gas pressure
--A fusible plug that melts to release gas
pressure in the event of fire
Before attaching regulator, open
cylinder valve slowly for discharge of
gas then close. **Place washer on “E”
·
Regulators
-Reduce
the gas pressure to a workable level (50psi)
--two
gauges: cylinder pressure and pressure of the gas
Single stage pressure regulators reduce
to 50 PSI in one step and has one pop
off
Double stage pressure regulators
reduce to a
working level in two steps. 150 and then
to 50 with two safety relief devices
--Regulators may be
preset or adjustable
>Preset is preset at
50 psig
>Adjustable can
vary pressure output
·
Flowmeters
>Uncompensated flowmeters will
inaccurately indicate flow in the
presence of backpressure.
--They do not work when positioned
on their side
>Compensated flowmeters accurate
in the presence of back pressure.
--Still position dependent
>Bourdon Gauge Flowmeter
--is accurate when laid on it’s side
n
Provide
medical air through portable or large
medical piping systems
n
Piston is used for large piping systems.
n
Diaphragm is used for portable
compressors
n
Rotary is used for nebulizers and IPPB
Flow can be adjusted from 1 to 10 L/min
but FiO2 is fixed at 40% at high flows
**Trouble-shooting tips
n
The molecular sieve type unit delivers
dry gas so humidity must be added
n
The permeable plastic membrane units
have a condensation jar that must be emptied
n
Both units have filters that should be
changed monthly
n
If a patient says that he or she cannot feel any gas coming
out of the cannula, have the patient place the prongs in a glass of water. If
no bubbling is seen, have the patient check for disconnects.
n
If the concentrator is malfunctioning, have the patient turn
it off and switch to a backup oxygen cylinder
A thermos-like tank (about 40" tall) filled with
liquid oxygen.
n
A smaller lightweight portable
unit can be filled off the
reservoir so the patient can
take the oxygen with them
when they leave home.
(HELIOS)
n
Liquid oxygen is especially
good for active people who
need to be out of the home on
a frequent basis.
n
50 psi gas source for each oxygen
and air
n
The blender has pressure regulating
valves and mixing controls that allow
FiO2s of 21-100% at flows of 2 to 100
L/min
**Audible alarm sounds if inlet
pressure decreases (Reed valve)
augmenting lung expansion, **Treat Atelectasis**
delivering aerosol
medication
n
Properly position patient (High-Fowler’s position)
If air does leak through the
nose, place nose clips or have them pinch their nostrils.
Adjust the pressure setting to
assure a comfortable breath that is about 25% more than their normal tidal
volume.
Continuously coach the patient
regarding deep breathing and an intermittent inspiratory hold. (3 sec)
**Troubleshooting**
n
The machine
will not cycle
>>Sensitivity set
incorrectly <# to>sensitivity
>>No gas source
>>Leaks in tubing
>>Leak around mouthpiece
>>Check flow control on
Bird Mark 7
n
The patient
can not cycle the machine off
>>Usually a sign of a leak.
>>Check all connections,
tubing, mask, mouthpiece, ETT, etc
>>If using the PR-2, turn
on the terminal flow to help >>compensate for a leak and check the
>>Check the expiratory
valve function
n
During
inspiration, the needle stays negative for the first half of the breath
>>Too little flow. Increase
flow
>>The machine cycles on
during the expiratory phase (chatters)
>>Decrease the machines
sensitivity
>>Ensure that the rate
control is turned off (PR-2)
>>Expiratory timing control
is off
q Is best
strategy for the prevention of atelectasis
q Also used to
treat atelectasis
q Should be done
hourly for about 10 breaths.
q Intolerated then use
alternate (PEP or IPPB)
q Percussion
Percussion is also referred to as
cupping, or clapping.
Applies kinetic energy to the chest wall
and lung to dislodge secretions
Should be
performed over each area for 3 to 5 minutes
q Vibration
Vibration involves the application of a
fine tremorous action (manually performed by pressing
in the direction that the ribs and soft tissue of the chest move during expiration)
over the draining area
q
High Frequency Chest Wall Oscillator
nonstretchable vest is worn.
Children as young as 3 years are able to use the vest. A treatment lasts 20-30mins (depending on the size of the chest).
The vest is
done sitting upright.
q
PEP Therapy
>This pressure allows air to enter
behind areas of mucus obstruction and keeps the airways open during exhalation.
>Used for
15-20 minute intervals, 3-4 times a day.
>The patient should be instructed to
inspire a larger than normal tidal volume and actively exhale but not
forcefully.
>Exhalation
is 2-3 times longer than inspiration
>Expiratory pressures range from
10-20 cmH20 at mid-exhalation
>PEP
resistance levels are adjustable. 10 to 20 cmH20
q
Flutter Valve
Exhaling produces oscillations of
pressure and airflow which vibrate the airway walls (loosening mucus)
Positive
expiratory pressure averages 10-25 cmH20
Treatment time is about 20 minutes.
Two common heliox mixture are
q 80% He and 20% O2
q 70% he and 30% O2
q The correction factor for the 80:20
mixture is 1.8
q The correction factor for the 70:30
mixture is 1.6
q non-rebreather or ventilated
Uses
rotating vane
Measures patient's tidal volume and minute volume. Can also
record FVC
Multiple
sampling of arterial blood, particularly in the mechanically ventilated patient
v
Pulse pressure
>Normally
80-100 mmHg
**Trouble
Shoot
v
Damped pressure tracing
>Occlusion
of catheter tip by clot
>Catheter
tip resting on wall of vessel
v
Clot in transducer or stopcock
>Air bubbles in line
>Abnormally high or low pressure
readings
>Improper calibration
>Improper transducer position (level
of heart)
v
No pressure reading
>Improper scale
>Transducer not open
to catheter
The
Swan-Ganz catheter is an important aid in monitoring
and treating the critically ill patient.
v
NBRC term - Flow directed pulmonary artery catheter
v
Mixed Venous
It is valuable in assessing cardiac, pulmonary, and fluid status in patients experiencing shock, CHF, pulmonary hypertension, pulmonary edema, and the use of high PEEP levels.
v
The Pleur-evac is a
three-chambered system
v
Approximately 1 to 2 cm of water is put in the water seal
chamber (middle)
v
Water rises toward the patient side of the chamber during
inspiration and returns to the other side on expiration
Important points:
Water level in the water seal
bottle will fluctuate with with normal breathing. If
there are no fluctuations, a blockage of the tube should be suspected.
Obstructed chest tubes may lead
to tension pneumos
v
Occasional bubbling is seen in the water-seal bottle
v
A constant bubbling in the water seal bottle may indicate
air leak; new or excessive bubbling must be reported immediately.
v
The system should always be lower than the chest to prevent
backflow
v
The system should be airtight
v
Additional suction is ordered at < -15 mmHg
v
Chest tube is usually kept in 1 to 2 days once the lung has
re-expanded
Can determine the pulse and presence of
perfusion as well as SaO2.
v
Factors affecting the accuracy of oximeters include:
Intensity of
ambient light
Patient and probe motion
The transmitted light intensity
Nail polish
Low perfusion or pulse intensity
Transcutaneous Electrodes measure
gas tension through the skin.
Trouble Shooting??
Self-contained
device that uses a propellant (CFC) to deliver a dose of medication
“Spacers” are
available for improved deposition
v
Dry Powder Inhalers (DPI)
>disperses dry powdered aerosol
>Requires faster inhalation than MDI
A procedure that involves direct visualization of the
patient’s trachea and bronchi.
v
Types of bronchoscopes:
Rigid and Flexible fiberoptic
- Rigid used on foreign body aspiration
Heat
is frequently used to eliminate microorganisms.
v
Boiling (100°C) kills within 10 minutes.
v
Steam under pressure (Autoclaving) (121°C for 15 min at 15 psi)
v
Pasteurization - hot
water bath at 63-70ºC for 30 minutes
v
Ethylene oxide is the gas most frequently used for
sterilization.
v
Gluderaldehyde submersion
for 10hrs at room temp. At 60 degrees Celsius
only needed for 1 hour.