Transcript Alternatives to IPPB: a tutorial

Alternatives to IPPB: a tutorial
By Elizabeth Kelley Buzbee AAS,
RRT-NPS, RCP
IPPB
• As we know, IPPB is the application of an
IC [inspiratory capacity] via application of
positive pressure sent into the lung with an
inline SVN, so that both IC and drugs are
delivered to the lung of a person who
cannot take a deep enough breath
spontaneously to distribute alveolar
ventilation and medication to the periphery
of the lung
Problems with IPPB
• The machines are fairly complex, break
down easily and the patient has to learn
some fairly complex skills to optimize his
therapy.
• The hazards of IPPB are associated with
the hazards of any form of positive
pressure: barotrauma and interference
with the cardiovascular system being the
worst
Alternatives to IPPB
• Over the last few years, as IPPB has
wained in popularity other forms of hyper –
inflation have evolved.
• Obviously, IS is one of these forms of
hyperinflation, but we will discuss a few,
more invasive forms of hyperinflation
today
PAP
• PAP: Positive Airway Pressure: advantage is that it
easier to do than IPPB; some methods don’t even
require a 02 source.
• Application of Positive Airway pressure can take several
forms:
–
–
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–
–
CPAP
EPAP
PEP
ezPAP
Retard valve [not really an alternative, but added to the IPPB]
We will discuss each of these 4 methods
CPAP
CPAP
• constant positive airway pressure breathing.
The pressure base line is raised from zero to a
positive number. The CPAP has only one
parameter and that is the baseline pressure.
• CPAP 5 means the baseline has risen to 5
cmH20. The patient breathes spontaneously on
this higher baseline pressure.
• For example: you normally breathe between -5
to zero. On IPPB you may alternate between -2
and +15, but with CPAP 5, you are breathing +3
to + 5.
CPAP
• While there are a variety of methods that CPAP
can be created, essentially in CPAP breathing,
the patient is not allowed to exhale completely
so that as he breathes, his airways are
subjected to a positive pressure throughout both
inspiration and exhalation.
• This is done, by creating an obstruction at the
exhalation port so that the exhalation valve fails
to open completely for the entire time.
• The actually pressure changes in CPAP are
minor only--- only about 2- 4 cmH20.
REFER: http://www.ccmtutorials.com/rs/mv/page3.htm
This pressure time curve shows a CPAP 10. Note, how as the patient breathes, the pressure
only varies a bit between inspiration and exhalation
Effects of CPAP
• Most likely, this CPAP action results in
backpressure sent along the airways and into
the periphery of the lung.
• Atelectatic alveoli will open [be recruited] and the
FRC should return to normal with the lung
compliance returning to normal.
• Alveoli are connected together with collateral
channels such as Pores of Kahn so that gas
moves from one set of alveoli to another.
• CPAP can be applied in one of two ways.
• Continuous CPAP
• Intermittent CPAP
Continuous CPAP
– The most common method is to place a patient on a
mechanical ventilator and rise the baseline pressure
for continuous application of CPAP.
– This method has replaced the Briggs adaptor
because more than a couple of hours breathing on a
Briggs adaptor [t-tube] will cause atelectasis in the
lung periphery due to increased Raw of the
endotracheal tube.
– Patients who come off mechanical ventilation used to
go on the t-tube for a few hours before extubation—
now we keep them on CPAP
– CPAP for long periods of time is generally limited to
low levels of pressure because high levels of CPAP
can cause hypercapnia as the Vt drops
Intermittent CPAP
• CPAP has been investigated as a short
term therapy for recruitment of alveoli.
• A patient is exposed to a few seconds of a
high level of CPAP.
• Follow up X-rays have shown increased
alveolar ventilation and a rise in Pa02 at
least for a short time.
• The long-term advantages of alveolar
recruitment procedures is not clear
Hazards of CPAP
• The problem with CPAP is that the
alveolar recruitment may only last 10
minutes after the Tx is over.
• CPAP can decrease venous return to the
right heart and reduce Cardiac output.
• Higher levels of CPAP can decrease the
Vt and PaC02 rises and the Ph drops to
acidic levels
EPAP
EPAP
 this is the baseline pressure on the BiPap machine. We
select EPAP and a pressure, and in the EPAP only
mode, it is, for all practical purposes, CPAP.
 The advantage of the BiPAP machine is that the patient
doesn’t have to be intubated, rather he uses a nose
mask for BiPap.
 In EPAP 5, the patient will alternate between +3 and
+5… just like with CPAP.
 This has not been done intermittently, but continually as
are most forms of mechanical ventilation --but because
the patient uses a mask, this technique could be used for
shorter periods of time.
BiPAP machine
Nose mask
EPAP hazards
• Same as CPAP.
EzPap
• This is a device that creates back pressure
within a small hand-held device that the patient
breathes through. It is not CPAP because the
variations between inspiratory and expiratory
pressure are much higher than with CPAP.
• EzPap uses a gas flow into a specially
constructed device to create
the higher pressures
• It can be used with a SVN
inline for drug delivery
or could be used dry
• Go to this page to access ezPAP online
video
• http://www.dhd.com/catalog/videos/
PEP
PEP
 PEP: [page 900-901 of Egan’s Fundamentals] is used in
both secretion clearance and in hyperinflation.
 In PEP positive expiratory pressure, there is no 02
flow into the device. Rather the patient exhales through a
restricted orifice creating back pressure up the airways.
This back pressure should transmit into the alveoli and
increase their diameter [and volume] just as CPAP does



http://www.respironics.com/product_
library/invoke.cfm?objectid=FF7A803A-969E
-4B62-B345FA1BF0A22432&method=display
EzPAP
ezPAP
 gas flow into a device where a positive
pressure on both inspiration and
exhalation occurs as the patient breaths
spontaneously.
 Different from CPAP in that there are
bigger changes in the higher pressure and
the lower pressure. This machine creates
these pressures with the Coanda effect
Note: this ezPAP has a SNV inline between the mouthpiece and
the ezPAP. This setup requires a drive line for the creation of
pressure [B] and a driveline A for the creation of the mist. The
third line C would go to a manometer
C
B
A
• Go here to find a sample patient
evaluation form for use with the ezPAP.
• This document includes indications,
contraindications and assessment tools
• http://www.dhd.com/pdf/EzPAP_Patient_E
valuation_Form.pdf
• Go to this website to access a video on
PEP
• http://www.dhd.com/catalog/videos/
Retard valve
• The retard valve is used with IPPB, so it
doesn’t replace the IPPB.
retard valve:
 additional pressure is placed on the exhalation
valves so that the exhalation is slower—this
mimics purse-lipped breathing. This valve
retards exhalation and creates backpressure to
keep the airways open.
 Retard valves should never be put on IPPB
exhalation valves without a specific order as
they have been associated with pneumothorax
 Expiratory retard is indicated in cases of
airtrapping to mimic purse-lipped breathing
• The expiratory retard valve on the Bennett IPPB
circuit replaced the usual exhalation valve. It
used a spring against the exhalation port that
could be tightened to keep gas in the circuit,
thus slowing down exhalation through the
exhalation valve by decreasing it’s diameter.
• The Bird uses a cap that fit over the exhalation
port that could be dialed from a larger port to a
smaller one to increase or decrease exhaled
flow rate
• These devices both caused restriction to
exhaled flow. [reference: Sills]
Problems with expiratory retard
• If the retard makes exhalation too slow, higher
pressure built up in the thoracic cavity,
decreases CO and exhalation is too slow.
• If the retard makes exhalation too fast, there
wasn’t enough retard to open the airway.
• Ask the patient how they feel about the results of
the retard valve. They can feel the difference in
their exhalation [refer: sills]
Reference page
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Egan’s page: 877-881
ezPAP web pages
PEP device web pages
McPherson’s Respiratory Care Equipment
Sill’s “Respiratory care Registry guide”