Chapter 18: Thorax and Lungs
Describe the most important points about the health history for the respiratory system
-Shortness of breath
-Chest pain with breathing
-History or respiratory infections
Describe the pleura and its function
– Thin, slippery pleura form an envelope between the lungs and chest wall
– Outside layer visceral; inside layer parietal
– Function: form cushion for lungs
– Pleural cavity has negative pressure or vacuum which holds the lungs tightly against chest wall
– Helps lungs slide smoothly
List the structures that compose the respiratory dead space.
Trachea & Bronchi
Summarize the mechanics of respiration.
Normally, our breathing pattern changes without our awareness in response to cellular demands. This involuntary control is mediated by the respiratory centre in the brainstem (pons and medulla). The major feedback loop is humoral regulation, or the change in carbon dioxide and oxygen levels in the blood, and less, importantly, the hydrogen ion level. Normal stimulus to breathe for most of us is an increase of carbon dioxide in the blood, or hypercapnia.
List the elements included in the inspection of the respiratory system
Posterior and lateral thorax; anterior chest
Discuss the significance of a “barrel chest”
Barrel chest has horizontal ribs and costal angle >90 degrees. Note equal anteroposterior-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.
List and describe common thoracic deformities
– Barrel chest: Note equal anteroposterior-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
Describe the three types of normal breath sounds.
Bronchial (Tracheal) High pitch; Loud Amplitude; Duration- inspiration < expiration; Quality - harsh, hollow tubular; Normal Loc - Trachea and Larynx
Bronchovesicular Moderate pitch; Moderate Amp; Duration - inspiration = expiration; Quality - mixed; Normal Loc - over major bronchi, where fewer alveoli are located
Vesicular Low pitch; Soft Amp; Duration - inspiration > expiration; Quality – rustling, like the sound of the wind in the trees; Normal Loc – Over peripheral lung fields, where air flows through smaller bronchioles and alveoli
Define 2 types of adventitious breath sounds.
Crackle- Discontinuous, brief, popping sounds
Wheezes-Continous musical sounds, high or low pitched, more noticeable on expiration
The manubriosternal angle is also called …?
Why is it useful for landmarks?
… angle of Louis.
Because it is continuous with the second rib
How many degrees is the normal costal angle?
When comparing the anteroposterior diameter of the chest to the transverse diameter, what is the expected ratio?
What is the significance of this?
1:2 or 5:7
Role in breathing cycle; inspire and exhale fully
What is the tripod position?
Leaning forward with arms braced against their knees, chair, or bed. This gives them leverage so that their rectus abdominis, intercostal, and accessory neck muscles all can aid in expiration.
List three factors that affect the normal intensity of tactile fremitus.
1. Relative location of bronchi to the chest wall
2. Thickness of the chest wall
3. Pitch and intensity
During percussion, which sound would you expect to predominate over normal lung tissue?
Normal findings for diaphragmatic excursion are:
3 to 5 cm… or 7 to 8 cm in well-conditioned people; it may be somewhat higher on the right side (1-2 cm) because of the presence of the liver.
List 5 factors that can cause extraneous noise during auscultation.
– Examiner’s breathing on stethoscope tubing
– Stethoscope tubing bumping together
– Patient shivering
– Patient’s hairy chest; movement of hairs under stethoscope sounds like crackles (rales)
– Rustling of paper gown or paper drapes