RESPIRATORY DISORDERS - Medicine for Mountaineering and Other Wilderness Activities - page 235

is usually a sign of infection but may occur with pulmonary embolism or HAPE. Serious
infection anywhere in the body causes fever, rapid pulse, and shortness of breath.
The first step in examining the chest is careful observation. Breathing difficulty, irreg-
ularities of respiratory rhythm, and differences in movement of the two sides of the chest
areimportant.Obvioussignsincluderapidorlaboredbreathing;shallow,irregular,ornoisy
breathing; and cyanosis (bluish discoloration) of the lips, nails, or skin. Flaring of the nos-
trils and tensing of the neck muscles are signs of severe respiratory difficulty. Efforts to
breathe that do not move the chest indicate upper airway obstruction.
The respiratory rhythm should be observed while counting the rate. Minor changes of
rhythmareofnosignificance;importantirregularitiesarehardtooverlook.Incontrast,dif-
ferencesinthemovementsofthetwosidesofthechestmaybesubtleandshouldbesought
during quiet respiration as well as during deep breathing.
Auscultation consists of listening to the sounds made by air passing in and out of the
lung.Astethoscopemakesthesoundseasiertohearandismoreconvenient,butthesounds
can be heard by pressing the unaided ear against the bare chest. Clothing must be removed
so important sounds and signs are not missed.
Quiet breathing by normal lungs produces sounds so faint that they are barely audible
exceptwithastethoscope.Thepersonbeingexaminedmustbeinstructedtobreathedeeply
through the mouth during the examination to amplify these sounds. All portions of the
lungs should be examined to be sure no abnormalities are missed and the extent of the dis-
eased area is recognized.
Many diseases of the lung cause fluid to collect in the small bronchi and alveoli, pro-
ducing crackling sounds on inspiration. Fluid accumulation is typical of infection or ed-
ema of the lungs. Wheezing, a high-pitched sound heard on expiration, is more indicat-
ive of asthma or chronic lung disease due to cigarette smoking (chronic bronchitis or em-
physema). With severe pneumonia or pulmonary embolism a portion of the lung is often
consolidated or airless due to fluid and inflammatory exudate in the alveolar sacs. Over
these areas, the breath sounds are harsher and louder because consolidated lung transmits
breath sounds from the bronchial tubes much more effectively than air in a normal lung.
These bronchial breath sounds are similar to the sounds, but differentiated from, those
heard directly over the trachea.
Infection or an embolus often produces inflammation of the pleura overlying the in-
volved lung, which makes the pleural surface rough. Since the pleural surfaces no longer
slide smoothly over each other, movement of the lung during respiration produces a
squeaking sound like two pieces of leather being rubbed together. This sound is called a
friction rub or simply a rub. Pain with a rub means pleurisy but does not define its cause.
If no sounds whatever are heard over a portion of the chest, fluid or air is usually in the
space between the lung and the chest wall. Rarely, the absence of breath sounds may be
due to obstruction of a large airway leading to that portion of the lung.