Respiratory System Disorders and Therapy From a New - Louis Bolk ...

3.1.2. Breathing Problems
The time relation between inhalation and expiration in the auscultation of normal
breathing sounds is 3:2. In asthma patients, the pathological expiration sound may take
as long as the inhalation or the relation may even be reversed. This symptom can persist
in the symptom-free period, as with our second patient. During the acute attack the
imbalance is usually much more pronounced.
Obstructed Expiration
The spastically prolonged expiration with wheezing is characteristic for asthma. Asthma
is an obstructive pulmonary disease, patients breathe out against a resistance. The
obstructed expiration is secondary to a decreased flexibility of bronchial tissue. The
resistance is due primarily to a spastic contraction of smooth muscle fibers. A swelling
of mucus membranes — ‘airway remodeling’ (section 2.1.2.) — and tenacious, viscous
mucus can further aggravate the obstruction. In asthma, the recoil of the lung is then
not able to effect expiration: to the contrary, muscular activity is needed to exhale and
even then may be insufficient. Expiration normally leads to relaxation after the activity
of inhalation. The sigh of relief is a good example of this (see box). In asthma, especially
during an exacerbation, relaxation is abrogated: the tension of inhalation is not resolved
in expiration, but rather increases in the sense of fig. 2.4.
The Relation of Inhalation to Heightened Awareness
We can further clarify the relation between inhalation and the abovedescribed
overalertness with an example. Under which circumstances does an
intensification of the inhalation normally occur? When a person is startled,
during mounting tension, and with an increase in chronic stress, inhalation
starts to dominate. The increased awareness accompanying shock or stress
deepens and accentuates inhalation. If the shock proves to be unfounded or
the tension disappears and we can allow our attention to slacken, then it is
most relaxing to let out a deep expiration: the ‘sigh of relief.’ In this example, it
is evident that the increase in inhalation is related to being more alert, or even
overalert. In hyperventilation, we can observe a similar phenomenon.