Intermittent Positive Pressure Breathing (IPPB)
IPPB (Intermittent positive pressure breathing pressure) therapy is defined as the
therapeutic application, usually via a mask or mouthpiece, of inspiratory positive pressure
to the airway of a spontaneously breathing patient on an intermittent or short-term basis
by an trained respiratory care practitioner (RCP). On an intermittent basis, IPPB
treatments usually last 15 to 20 minutes, and may be given several times each day. Shortterm use is for purposes of assisting ventilation, and may be provided over a period of
several hours, such as overnight.
Overview
IPPB was came into use as a clinical modality in
1947, and since then it has had a roller-coaster type
history. When it was first introduced, IPPB enjoyed
almost immediate widespread acclaim, and was
used for a broad range of clinical conditions. By
1970, despite a sparcity of clinical evidence
supporting its use, IPPB had become the
preeminent mode of respiratory therapy. Many
physicians seemed to order IPPB treatments simply
because they preferred doing something (even
though there was little evidence of benefit for many
patients) rather than doing nothing. However, as
cost-consciousness began to be a predominant
factor in health care decisions, the expenses
associated with IPPB would eventually change all
that.
The use of IPPB therapy has been controversial for more than three decades. It came
under attack as both an unvalidated and overused treatment modality. The Respiratory
Care Committee of the American Thoracic Society (ATS), in 1980, prepared guidelines
for limiting the use of IPPB certain clearly defined clinical situations. Later in the 1980s,
the American Association for Respiratory Care (AARC) issued a statement asserting that
the effectiveness of IPPB was actually limited to several, very specific clinical situations.
Eventually, the AARC established clear clinical practice guidelines for the use of IPPB
therapy. Clearly, IPPB should neither be totally condemned nor universally applied.
Critics demanding specific physiologic evidence supporting the qualitative and
quantitative benefits of IPPB need to be reminded that standardization of administration
is necessary for legitimate studies of the efficacy of treatment regimens. This kind of
standardization is difficult when mechanical or manipulative regimens like IPPB are
being studied. On the other hand, supporters of IPPB's effectiveness need to recall that
unsubstantiated clinical impression and dogma are not the same as irrefutable clinical
evidence. Like so many other respiratory care modalities, the effectiveness of IPPB
requires that:
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patients be carefully selected
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the indications for therapy be specifically defined
the goals of therapy be clearly understood
the treatment be properly administered by a trained RCP The key to being able to
accurately assess a treatment modality's efficacy is to evaluate how well it
accomplishes its goals, and to review the goals of IPPB it is necessary to first
understand the physiological basis and impact of IPPB.
Physiologic Principles
If IPPB is to be successful, it must increase alveolar distending pressure. This is
accomplished by increasing alveolar pressure so that the difference between alveolar and
pleural pressure also is increased.
IPPB reverses the normal spontaneous pressure gradients. Instead of negative alveolar
pressure causing gas flow into the lungs, positive pressure at the airway opening creates
the needed gradient. The rise in alveolar pressure increases PL and expands the alveoli.
When alveolar distending pressures are increased, a large volume of gas exists within the
airway. Gas flows from the airway into the lungs, and alveolar pressures rise during the
inspiratory phase of IPPB. As a result of these pressure changes, four physiologic effects
can be attributed to IPPB:
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An increase in mean airway pressure
A decrease in the work of breathing (WOB)
Manipulation of the inspiratory-expiratory ratio
Increase in tidal volume (VT)
Appropriate application of IPPB may result in a stressed patient accepting and being
comfortable with ventilatory patterns they could not tolerate during spontaneous
breathing. When an increased WOB exists, intermittent positive pressure may allow the
same degree of physiologic ventilation with far less expenditure of muscular energy.
Examples
Description
Bird Mark - 7
Pneumatically powered assist/controller pressure
ventilator for delivery of IPPB therapy. Requires gas
source of 50 pounds per square inch.
Bird Mark - 8
Same features as Mark-7 plus adjustable expiratory
flow rate providing positive (PEEP)/negative (NEEP)
end expiratory pressure.
Bird Mark - 10
Leak compensating IPPB ventilator with Mark-7
features.
Bird Mark - 14
Leak compensating IPPB ventilator with Mark-7
features plus extended range of flow and pressure.
Electrically powered IPPB with AP-5 features plus cover
Puritan Bennett APand handle modifications for storage and transport.
4
Convenient for homecare or hospital use.
Puritan Bennett AP- Electrically powered IPPB therapy unit with internal
5
motor/compressor. Ideal for homecare or hospital use.