ch.19 - thorax and lungs

3 points that commonly confuse beginning examiners

1. The left lung has no middle lobe.

2. The anterior chest contains mostly upper and middle lobe with very little lower lobe.

3. The posterior chest contains almost all lower lobe.

four major functions of the respiratory system

(1) supplying oxygen to the body for energy production; (2) removing carbon dioxide as a waste product of energy reactions; (3) maintaining homeostasis (acid-base balance) of arterial blood; and (4) maintaining heat exchange (less important in humans)

mechanical expansion and contraction of the chest cavity alters the size of the thoracic container in two dimensions

(1) the vertical diameter lengthens or shortens, which is accomplished by downward or upward movement of the diaphragm; and (2) the anteroposterior (AP) diameter increases or decreases, which is accomplished by elevation or depression of the ribs

changes in aging adult

costal cartilages become calcified; thus the thorax is less mobile, muscle strength declines, decrease in elastic properties within the lungs, making them less distensible and lessening their tendency to collapse and recoil, decreased compliance, stiffer, harder to inflate, increased residual volume (the amount of air remaining in the lungs even after the most forceful expiration), greater risk for postoperative atelectasis and infection from a decreased ability to cough, a loss of protective airway reflexes, and increased secretions

Eliminating TB is slowed by many factors:

poverty, health system inadequacies, and biological factors such as HIV co-infection, drug resistance, and persistent presence of many latent TB infections

characteristic cough:

mycoplasma pneumonia—hacking;

early heart failure—dry;

croup—barking;

colds, bronchitis, pneumonia—congested.

Paroxysmal nocturnal dyspnea

awakening from sleep with SOB and needing to be upright to achieve comfort.

Neck muscles are hypertrophied

in COPD from aiding in forced respirations across the obstructed airways.

Unequal chest expansion

occurs with marked atelectasis, lobar pneumonia, pleural effusion, thoracic trauma such as fractured ribs, or pneumothorax

Decreased fremitus

occurs with obstructed bronchus, pleural effusion or thickening, pneumothorax, or emphysema. Any barrier that comes between the sound and your palpating hand decreases fremitus.

Increased fremitus

occurs with compression or consolidation of lung tissue (e.g., lobar pneumonia). This is present only when the bronchus is patent and the consolidation extends to the lung surface. Note that only gross changes increase fremitus. Small areas of early pneumonia do not significantly affect it.

Rhonchal fremitus

is palpable with thick bronchial secretions.

Pleural friction fremitus

palpable with inflammation of the pleura

Crepitus

a coarse, crackling sensation palpable over the skin surface. It occurs in subcutaneous emphysema when air escapes from the lung and enters the subcutaneous tissue, as in tension pneumothorax or after open thoracic injury or surgery.

BRONCHIAL (TRACHEAL)

High Loud Inspiration < expiration Harsh, hollow tubular Trachea and larynx

BRONCHOVESICULAR

Moderate Moderate Inspiration = expiration Mixed Over major bronchi where fewer alveoli are located: posterior, between scapulae especially on right; anterior, around upper sternum in 1st and 2nd intercostal spaces

VESICULAR

Low Soft Inspiration > expiration Rustling, like the sound of the wind in the trees Over peripheral lung fields where air flows through smaller bronchioles and alveoli

Decreased or absent breath sounds occur:

1. When the bronchial tree is obstructed

2. In emphysema as a result of loss of elasticity in the lung fibers and decreased force of inspired air

3. When anything obstructs transmission of sound between the lung and your stethoscope

Increased breath sounds

high-pitched, tubular quality, with a prolonged expiratory phase and a distinct pause between inspiration and expiration. They sound very close to your stethoscope, as if they were right in the tubing close to your ear. They occur when consolidation (e.g., pneumonia) or compression (e.g., fluid in the intrapleural space) yields a dense lung area that enhances the transmission of sound from the bronchi.

crackles (or rales)

discontinuous popping sounds heard over inspiration

wheeze (or rhonchi)

continuous musical sounds heard mainly over expiration

Atelectatic crackles

short, popping, crackling sounds that last only a few breaths, heard only in the periphery, usually in dependent portions of the lungs, and disappear after the first few breaths or after a cough.

Hypertrophy of abdominal muscles

occurs in chronic emphysema.

Noisy breathing

occurs with severe asthma or chronic bronchitis.

Unequal chest expansion

occurs when part of the lung is obstructed (pneumonia) or collapsed or when guarding to avoid postoperative or pleurisy pain

Retraction

suggests obstruction of respiratory tract or that increased inspiratory effort is needed, as with atelectasis.

Bulging

indicates trapped air as in the forced expiration associated with emphysema or asthma.

Accessory muscles are used in

acute airway obstruction and massive atelectasis.

lag in expansion

occurs with atelectasis, pneumonia, and postoperative guarding.

palpable grating sensation with breathing

indicates pleural friction fremitus

Barrel Chest

equal AP-to-transverse diameter and that ribs are horizontal instead of the normal downward slope. This is associated with normal aging and also with chronic emphysema and asthma as a result of hyperinflation of lungs.

Pectus Excavatum

markedly sunken sternum and adjacent cartilages (also called funnel breast). Depression begins at second intercostal space, becoming depressed most at junction of xiphoid with body of sternum. More noticeable on inspiration. Congenital, usually not symptomatic. When severe, sternal depression may cause embarrassment and a negative self-concept.

Pectus Carinatum

forward protrusion of the sternum, with ribs sloping back at either side and vertical depressions along costochondral junctions (pigeon breast).

Sigh

Occasional sighs punctuate the normal breathing pattern and are purposeful to expand alveoli. Frequent sighs may indicate emotional dysfunction and also may lead to hyperventilation and dizziness.

Cheyne-Stokes Respiration

respirations gradually wax and wane in a regular pattern, increasing in depth and then decreasing until apnea occurs. The breathing periods last 30 to 45 seconds, with periods of apnea (20 seconds) alternating the cycle. The most common cause is severe heart failure; other causes are renal failure, meningitis, drug overdose, and increased intracranial pressure

Biot Respiration

Similar to Cheyne-Stokes respiration, except that the pattern is irregular. A series of normal respirations (3 to 4) is followed by a period of apnea. The cycle length is variable, lasting anywhere from 10 seconds to 1 minute. Seen with head trauma, brain abscess, heat stroke, spinal meningitis, and encephalitis.

Chronic Obstructive Breathing

Normal inspiration and prolonged expiration to overcome increased airway resistance. In a person with chronic obstructive lung disease, any situation calling for increased heart rate (exercise) may lead to dyspneic episode (air trapping) because the person does not have enough time for full expiration.

Increased Tactile Fremitus

Occurs with conditions that increase the density of lung tissue, thereby making a better conducting medium for vibrations (e.g., compression or consolidation [pneumonia]).

Decreased Tactile Fremitus

Occurs when anything obstructs transmission of vibrations (e.g., an obstructed bronchus, pleural effusion or thickening, pneumothorax, and emphysema).

Rhonchal Fremitus

Vibration felt when inhaled air passes through thick secretions in the larger bronchi. This may decrease somewhat by coughing.

Pleural Friction Fremitus

Produced when inflammation of the parietal or visceral pleura causes a decrease in the normal lubricating fluid. The opposing surfaces make a coarse grating sound when rubbed together during breathing. This sound is best detected by auscultation, but it may be palpable and feels like two pieces of leather grating together. It is synchronous with respiratory excursion. Also called a palpable friction rub.

Crackles—Fine (formerly called rales)

Discontinuous, high-pitched, short crackling, popping sounds heard during inspiration that are not cleared by coughing

Crackles——Coarse

Loud, low-pitched bubbling and gurgling sounds that start in early inspiration and may be present in expiration

Wheeze—High-pitched (sibilant)

High-pitched, musical squeaking sounds that sound polyphonic (multiple notes as in a musical chord);

Wheeze—Low-pitched (sonorous rhonchi)

Low-pitched; monophonic, single-note, musical snoring, moaning sounds; they are heard throughout the cycle

Stridor

High-pitched, monophonic, inspiratory, crowing sound

continuous sounds

connected, musical sounds: Wheeze—High-pitched (sibilant), Wheeze—Low-pitched (sonorous rhonchi), stridor

discontinuous sounds

discrete, crackling sounds: Crackles—Fine (formerly called rales), Crackles——Coarse, Atelectatic crackles, Pleural friction rub