Page 36 - Critical Care Nursing Demystified

Chapter 2 CARE OF THE PATIENT WITH CRITICAL RESPIRATORY NEEDS 21

pathology occurs from disease, the work of breathing can increase significantly
above normal due to decreased lung compliance

KEY POINT Normal ventilation depends on the following factors:
1. Flexibility of the rib cage
2. Elasticity of the lungs
3. Normal action of the muscles of ventilation

4. Normal airway proficiency, which relies on:
a. Ventilation: movement of gases into and out of the lungs
b. Perfusion: the flow of blood through body parts

c. Diffusion: the flow of gases across the alveolar capillary membranes from areas

of higher to lower concentrations

Try to remember those grueling days of your anatomy and physiology classes,
and how you promptly forgot everything that you memorized after completing
those courses. Give yourself much credit, because you probably remember
more than you realize. However, a brief review of the anatomy and physiology Downloaded by [ Faculty of Nursing, Chiangmai University 5.62.158.117] at [07/18/16]. Copyright © McGraw-Hill Global Education Holdings, LLC. Not to be redistributed or modified in any way without permission.
of the respiratory system can only strengthen your current knowledge base. To
begin with, the respiratory system promotes gas exchange between the internal
and external environments by inhaling and moving oxygen from the air into the
blood and removing carbon dioxide or exhaling it from the blood into the
external environment. The process of ventilation includes inspiration and expi-
ration, which allows movement of air into and out of the lungs. Respiration
allows for the gas exchange of oxygen delivery to the entire body and the
removal of excess carbon dioxide buildup from the body.
The respiratory system also regulates the acid-base balance, metabolizes cer-
tain compounds, and filters out inhaled and unnecessary materials from the
external environment. Structures of the respiratory system are described in the
following text.
The thorax is a rigid yet flexible bony structure that protects major organs
within the thoracic cavity. The thorax must be flexible to allow for the inhala-
tion and inflation, as well as the exhalation and deflation, of the lungs. The bony
structure of the thorax is composed of 12 vertebrae, 12 pairs of ribs, and
the sternum. Ribs are attached posteriorly to vertebrae and anteriorly to
the sternum. The 11th and 12th ribs are the exceptions and are known as “float-
ing ribs” because anteriorly they are NOT attached to any other structures (see
Figure 2–1).