Anatomy and Function of Respiratory System, ch20

Question 1

Lung Anatomy Breakdown

Answer 1

Lobar bronchi (3 in R, 2 in L), divide into segmental bronchi (10R, 8L) to facilitate effective postural drainage . Then subsegmental bronchi. Surrounded by arteries, lymphatics, nerves. Subsegmental bronchi branch into bronchioles. Bronchioles have no cartilage in their walls – patency depends on smooth muscle and alveolar pressure. Bronchioles branch into terminal bronchioles – no mucus glands or cilia. These become respiratory bronchioles, considered to be transitional passageways between conducting airways and gas exchange airways. Respiratory bronchioles lead into alveolar ducts and sac and then alveoli. Oxygen and carbon dioxide exchange takes place in the alveoli.

Question 2

Alveoli

Answer 2

300 million alveoli in a lung. 3 types of alveolar cells.
Type 1 and type II make up alveolar epithelium
Type 1 account for 95% of alveolar surface area. barrier between air and the alveolar surface.
Type II - only 5% of surface area but they are responsible for producing type 1 cells and surfactant - surfactant reduces surface tension
Alveolar macrophages are type III - phagocytic cells that ingest foreign matter, defense mechanism

Question 3

Oxygen Transport

Answer 3

Oxygen is supplied and CO2 is removed by circulating blood through capillaries. Through capillary walls to interstitial fluid, through membrane of tissue cells, used by mitochondria for cellular respiration. CO2 moves by diffusion in opposite direction, from cell to blood

Question 4

Respiration

Answer 4

From tissue capillary changes, blood enters venous circulation and travels to the pulmonary circulation. There is a concentration gradient, the O2 concentration in blood within capillaries of lungs is lower than in the lungs alveoli, so oxygen diffuses from alveoli to the blood
CO2 has higher concentration in blood than in alveoli. Diffuses from blood into alveoli. Air in and out removes CO2

Question 5

Ventilation

Answer 5

Inspiration occurs through first third of respiratory cycle. Expiratory phase is latter two thirds. Inspiratory phase requires energy, expiratory phase is passive and requires little energy. What governs airflow in and out is air pressure variance, resistance to airflow, and lung compliance

Question 6

compliance

Answer 6

factors that determine lung compliance are the surface tension of the alveoli, the connective tissue and water content of the lungs, and compliance of thoracic cavity. Compliance is normal if they stretch easily and distend when pressure is applied. Increased compliance if they lose their elastic recoil and become overdistended (emphysema) decreased compliance if lungs/thorax are stiff, like pneumothorax, hemothorax, pleural effusion, pulmonary edema, atelctasis, ARDS. decreased compliance require greater than normal energy expenditure

Question 7

Lung Volume

Answer 7

categorized as tidal volume, residual volume, inspiratory reserve volume, expiratory reserve volume
volume of air inhaled and exhaled with each breath
500ml

Question 8

Lung Capacity/ Vital Capacity

Answer 8

evaluated in terms of vital capacity, inspiratory capacity, functional residual capacity, total lung capacity

the maximum volume of air exhaled from the point of maximum inspiration. 4,600 mL
vital capacity = tidal volume + inspirator reserve volume + expiratory reserve volume

Question 9

ventilation/perfusion ratio

Answer 9

Adequate ventilation/perfusion ratio: airway blockages, changes in compliance, gravity, can alter ventilation. Alterations in perfusion can occur with changes in pulm artery pressure, alveolar pressure, gravity. Imbalance is when there is inadequate ventilation or perfusion or both. Normal ratio, low ratio (shunt), high ratio (dead space) and absence of v/q (silent unit). V/Q imbalances cause shunting of blood, which results in hypoxia. Severe hypoxia is when shunting exceeds 20%

Question 10

reserve volume

Answer 10

reserve volume is about 1,100 mL

Question 11

Neurologic Control of Ventilation

Answer 11

Inspiratory and expiratory centers in medulla oblongata and pons control rate and depth of ventilation. Receptors in medulla respond to increase or decrease in pH and tell lungs to change depth and rate of ventilation to correct the imbalance. Mechanoreceptors in the lung respond to stretch, irritant, and resistance by altering breathing patterns to support optimal lung function. Proprioceptors in muscle and chest respond to body movements and increase ventilation - while mobility helps bedbound pts breath better.

Question 12

CO2

Answer 12

When oxygen diffuses from the blood to the tissues, carbon dioxide diffuses from the tissue cells to the blood and transported to the lungs for excretion. The amount of CO2 in transit is a major determinant of acid-base balance. Normally, only 6% of venous carbon dioxide is removed in the lungs. There should be enough CO2 remaining in arterial blood to exert pressure of 40mm Hg. Most CO2 is carried by red blood cells. 5% remains that is dissolved in plasma, and this is the critical factor that determines CO2 movement in or out of blood.

Question 13

Gerontologic

Answer 13

gradual decline begins in early to middle adulthood

Question 14

Defense Mechanisms (Age-related changes, Respiratory)

Answer 14

decrease in: # cilia, mucus, cough and gag reflex
loss of : surface area of cap membrane
lack of consistent ventilation and/or blood flow

decreased protection against foreign particles, decrease protection against aspiration, decrease antibody response to antigens, decrease response to hypoxia

increase of infection rate, respiratory infections, COPD, pneumonia

Question 15

Lung (Age-related changes, Respiratory)

Answer 15

decrease size of airway, elasticity of alveolar sacs
increase: diameter of alveolar ducts, collagen of alveolar walls, thickness of alveolar membranes

increase: airway resistance, pulmonary compliance, dead space, air trapping
decrease: expiratory flow rate, oxygen diffusion capacity, exercise capacity

increase in residual volume, CO2
decrease in inspiratory volume reserve, expiratory volume reserve, forced vital capacity, PaO2

Question 16

Chest Wall/Muscles (Age-related changes, Respiratory)

Answer 16

calcification of intercostal cartilages, arthritis of costovertebral joints, decrease in diaphragm, osteoporotic changes, decrease muscle mass, muscle atrophy

increase in rigidity and stiffness of thoracic cage
increase work of breathing, risk for inspiratory muscle fatigue
decrease muscle strength, capacity for excerise

S/S barrel chest, skeletal changes, abdominal and diaphragmatic breathing, decrease expiratory flow rates

Question 17

Health Assessment (Respiratory)

Answer 17

Focus on presenting problem and s/s. Also: onset, location, duration, character, aggravating factors, alleviating factors, radiation, time of presenting problem

Question 18

Dyspnea

Answer 18

Difficult or labored breathing, breathlessness, shortness of breath. Indicates decreased lung compliance or increased airway resistance
Usually indicative of pulmonary and cardiac disorders, but can be associated with allergic reactions, anemia, neurologic or neuromuscular disorders, advanced disease, trauma
Acute onset is more severe than chronic. Sudden dyspnea (in healthy prs) can indicate pneumothorax (air in pleural cavity), acute respiratory obstruction, allergic reaction, or MI
Also seen with: orthopnea (inability to breath easily except in an upright position), hypoxemia, tachypnea. Noisy breathing may result from a narrowing of the airway, or localized obstruction of major bronchus. Dyspnea with expiratory wheeze occurs in COPD. Stridor is the high-pitched sound heard when someone is breathing through partially blocked upper airway

Question 19

Cough

Answer 19

Reflex that protects the lungs from accumulation of secretions or inhalation of foreign bodies. Some disorders trigger coughing and some suppress it. Cough can be from irritation or inflammation of mucous membranes anywhere in respiratory tract. Common causes include asthma, GERD, infection, aspiration, or side effects of meds like ACE inhibitors

Question 20

Sputum

Answer 20

Can be caused by recurring irritant, persistent coughing, or nasal discharge. What is the cause? Is it purulent, thick, yellow/green? → bacterial infection
Thin, mucoid sputum → viral bronchitis
Profuse, frothy, pink, welling into throat → pulmonary edema

Question 21

Chest Pain (Respiratory)

Answer 21

Chest pain with pulmonary conditions can be sharp, stabbing, intermittent, or dull, aching, persistent. Occurs usually with pneumonia, pulmonary infarction, pleurisy, carcinoma. No pain receptors in lung or visceral pleura, only parietal pleura, which can be stimulated by inflammation and stretching of membrane. Pleuritic pain: sharp, catches on inspiration, stabbing. Laying on side that hurts helps to feel better because of sensation of splinting the chest wall. Assess quality, intensity, radiation of pain. Positional? Inspiratory? expiratory?

Question 22

Wheezing

Answer 22

High pitched. Musical. Mainly on expiration (probably due to asthma) or inspiration (probably due to bronchitis). Major finding with bronchoconstriction or airway narrowing.
Rhonchi is low pitched continuous sounds.

Question 23

hemoptysis

Answer 23

Expectoration of blood from respiratory tract. Onset is usually sudden. May be intermittent or continuous. Most common causes: pulmonary infection, carcinoma of lung, abnormalities of heart or blood vessels, pulmonary arteries or vein abnormalities, pulm embolus and infarction. Determine source of bleeding. Blood from lung is usually bright red, frothy, mixed with sputum

Question 24

Past Health, Social, Fam Hx

Answer 24

Immunizations, childhood illnesses, medical conditions, allergies
Diet, exercise, sleep
What are risk factors? Smoke, race, SES,
Risk Factors for respiratory disease: smoking. Second hand smoke. Hx of lung disease. Genetic. Allergens or pollutants. Occupation hazards. Obesity. Vitamin d deficiency.
Asthma, COPD, cystic fibrosis are influenced by genetics

Question 25

Cyanosis

Answer 25

Cyanosis is a very late indicator of hypoxia. Determined by amount of unoxygenated hemoglobin in blood. Unoxygenated hemoglobin (at least 5g/dL) reduces effective circulation. Cyanosis is not a reliable sign of hypoxia. (anemia may rarely be cyanotic. Polycythemia may be false cyanotic).

Question 26

upper respiratory structures

Answer 26

Assess nose, sinuses, mouth, pharynx, trachea. Mucosa, lesions, exudate, bleeding, inflammation

Question 27

Lower respiratory structures

Answer 27

Proper assessment includes inspecting, palpating, auscultating, percussion. Posterior thorax and lungs: pt should be sitting. Anterior: pt should be supine. Note thorax for color and turgor. Chest configuration: four main deformities associated with respiratory disease: barrel chest, funnel chest, pigeon chest, kyphoscoliosis

Question 28

Chest deformities

Answer 28

Barrel chest: overinflation of lungs. Hallmark sign of emphysema and COPD. emphysema: ribs bulge on expiration. Funnel Chest (pectus excavatum): depression in lower portion of sternum. Compresses heart and great vessels, resulting in murmurs. Can occur with rickets or marfan’s syndrome. Pigeon chest (pectus carinatum): anterior displacement of sternum. Increases anteroposterior diameter. Occurs with rickets, marfan syndrome, or severe kyphoscoliosis Kyphoscoliosis: elevation of scapula and s-shaped spine. Limits lung expansion within thorax. Can occur with oseoporosis

Question 29

lung landmarks

Answer 29

Suprasternal notch- between both clavicles Angle of Louie - at second intercostal space C7 - spiny notch Midsternal line Midclavicular line Midauxillary line

Question 30

respiratory patterns (5)

Answer 30

Eupnea is normal Bradypnea - less than 10. Normal depth & rhythm. Associated with increased cranial pressure, brain injury, drug overdose Tachypnea- rapid, shallow. Greater than 24. Associated with pneumonia, pulm edema, metabolic acidosis, septicemia, severe pain, rib fracture Hypoventilation: shallow, irregular breathing Cheyne-stokes: regular cycle, rate and depth increase and then decrease, followed by apnea (about 20 seconds). Sometimes period of apnea lengthens. Associated with heart failure, damage to respiratory center - drug induced, tumor, trauma

Question 31

Accessory Muscle Usage

Answer 31

Inspiration: look for sternocleidomastoid, scalene, trapezius muscles. Expiration: abdominal, internal intercostal

Question 32

Thoracic Palpation, Excursion, Fremitus

Answer 32

Palpate thorax for tenderness, masses, lesions, respiratory excursion, vocal fremitus Respiratory excursion is estimate of thoracic expansion. Assess for range and symmetry. Watch that thumbs move equally. Asymmetric excursion may be due to splinting secondary to pleurisy, fractured ribs, trauma, unilateral bronchial obstruction Fremitus: vibrations on chest wall from speech detected on palpation. Sound usually travels distally along bronchial tree in resonant motion. Influenced by many factors such as thickness of chest wall, muscle, subcutaneous tissue, pitch. Air does not conduct sound well - solid substances like tissue does. Solid tissue enhances fremitus. An increase in air per unit volume of lung impedes sound. Emphysema exhibits no fremitus. Consolidation of a lobe of lung from pneumonia has increased fremitus over lobe. Air in pleural space does not conduct sound

Question 33

percussion

Answer 33

COPD and emphysema will have hyperresonant sounds. Percussion helps to figure out if underlying tissues are filled with air, fluid, or solid material. Healthy lung tissue is resonant. Dullness over lung is when air-filled lung tissue is replaced by fluid or solid tissue. Percussion begins with posterior thorax. Normal resonance of lung stops at diaphragm. Maximal excursion is usually 5-7 cm. Decreased excursion occurs with pleural effusion. For diaphragms positioned high in thorax, atelectasis, diaphragmatic paralysis, or pregnancy can be accounted for moving it there

Question 34

thoracic auscultation

Answer 34

Assessing flow of air through bronchial tree. Presence of fluid or solid obstruction. Listen for normal breath sounds, adventitious sounds, voice sounds. In pleural effusion, air sounds are decreased at bases. Fluid accumulates first in bases.

Question 35

Breath Sounds

Answer 35

Vesicular, bronchovesicular, bronchial. Assess location, quality, intensity. Atelectasis decreases airflow by bronchial obstruction. Pleural effusion causes fluid to fill air passages. This causes diminished or absent breath sounds. Adventitious sounds affects bronchial tree and alveoli. Discrete, discontinuous sounds are crackles. Continuous musical sounds are wheezes. Friction rubs can be discontinuous or continuous.

Question 36

respiratory distress

Answer 36

Respiratory distress usually characterized by nasal flaring, excessive use of intercostals and accessory muscles, uncoordinated movement of chest and abdomen, sob)

Question 37

Minute Ventilation

Answer 37

Tidal volume multiplied by respiratory rate provides minute ventilation. Which is the volume of air exchanged per minute. Helps detect respiratory failure. Measured using spirometer. When minute volume falls, alveolar ventilation in lungs also decreases, and PaCO2 increases.

Question 38

Vital Capacity

Answer 38

Measured by having pt take in a maximal breath and exhale fully through spirometer. Most patients can generate VC twice the volume they normally breathe in and out (so twice tidal volume). If vital capacity is less than 10mL/kg then pt wont be able to sustain spontaneous ventilation. When VC is exhaled at max flow rate, forced vital capacity is measured. Usually able to exhale 80% of vital capacity in 1 sec. (FEV) Reduction in this indicates abnormal pulm airflow.

Question 39

ABGs

Answer 39

assess ability of lungs to provide adequate oxygen and remove carbon dioxide - this reflects ventilation, and ability of kidneys to reabsorb or excrete bicarbonate ions to maintain normal pH - reflecting metabolic states. Obtained through radial, brachial, or femoral artery, indwelling catheter.

Question 40

cultures

Answer 40

Throat, nasal, and nasopharyngeal cultures can identify pathogens responsible for respiratory infections, such as pharyngitis. Results usually take between 48-72 hours.

Question 41

sputum studies

Answer 41

Obtained to determine if pathogenic organisms are present. Usually necessary for pts on prolonged periods of antibiotics, corticosteroids, and immunosuppressive meds because those are associated with opportunistic infections. Better to be obtained in the early morning. Take deep breaths, cough deeply, expectorate sputum from lungs into sterile container. Can use endotrach or transtracheal aspiration if necessary

Question 42

Chest XRay

Answer 42

Normal pulmonary tissue is radiolucent because it consists mostly of air and gases - densities produced by tumors, fluid, foreign bodies, or other conditions can be detected by xray examination. Take after full inspiration to best visualize lungs. Contraindicated in pregnant women.

Question 43

CT scan

Answer 43

CT scan: lungs scanned in successive layers. Produce cross sectional view of chest. Can distinguish fine tissue density. Can define pulmonary nodules, small tumors. Contrast agents used. Used routinely in pulm angiogram to diagnose pulmonary emboli. Contraindicated for allergy to dye, pregnancy, obesity. Potential complications include acute renal failure, acidosis secondary to contrast

Question 44

MRI

Answer 44

MRI: radiofrequency signals used instead of radiation. Better distinguishes between normal and abnormal tissue when compared to CT scan, yields more detailed diagnostic. Characterizes pulm nodules, assess stages of cancer, evaluate inflammation, acute pulm embolism, pulm hypertension. Must remove metal.

Question 45

Fluoroscopy

Answer 45

Fluoroscopic Studies: allows live xray to be generated to video screen. Used for invasive procedures such as biopsies to identify lesions. Or to study movement of chest wall, mediastinum, heart, diaphragm

Question 46

pulmonary angiography

Answer 46

Pulmonary Angiography: investigates congenital abnormalities of pulm tree and thromboembolic disease such as pulm emboli. Radiopaque agent is injected through catheter to visualize pulm vessels. Catheter goes in through vein - jugular, subclavian, brachial, femoral). Contraindications: allergy to dye, pregnancy, bleeding, acidosis. Potential complications: bleeding, dysrrhythmias, renal failure. Requires informed consent. Check drug allergies. Check anticoag status and renal function. NPO? Yes, for 6-8 hours prior. After procedure, monitor vital signs, o2 sat, bleeding at site, level of consciousness.

Question 47

V/Q Scan

Answer 47

V/Q scan: prn lock in, awake, no conscious sedation required. Assess normal lung functioning, pulm vascular supply, gas exchange. Inject radioactive agent into peripheral vein-then scan chest to detect radiation. Measures blood perfusion through the lung. Measures integrity of pulmonary vessels relative to blood flow. Evaluates blood flow abnormalities. 20-40minutes for imaging. Ventilation component: pt breaths mix of oxygen and radioactive gas, diffuses throughout lungs, scan detects ventilation abnormalities. Helps to diagnose bronchitis, asthma, inflammatory fibrosis, pneumonia, emphysema, lung cancer, pe. IV access required. Chest xray should be done before this scan. Pt can eat/drink prior.

Question 48

bronchoscopy

Answer 48

Bronchoscopy – a scope through trachea into lungs. Better idea of whats going in trachea/bronchi. Can get tissue samples. Direct inspection of larynx, trachea, bronchi. Determines nature, location, extent of pathologic process. Collects secretions for analysis, obtain tissue sample. Diagnose source of hemoptysis. Diagnostic vs therapeutic. Therapeutic can control bleeding, remove foreign bodies, destroy lesions, insert stents. Fiberoptic vs rigid bronchoscope. Nurse should assess Vitals, o2 sat. Requires Conscious sedation, npo. Requires informed consent. Fluid held 4-8 hrs prior to reduce risk of aspiration. Preoperative meds include atropine, sedative, to inhibit vagal stimulation. This guards against bradycardia, dysrhythmias, hypotension, suppress cough reflex . performed under local anesthesia or moderate sedation. Lidocaine typically used. Npo postop until cough reflex returns. Monitor respiratory status. Observe for hypotension, tachycardia, hemoptysis, dyspnea. Blood tinged sputum and low fever are expected/normal. Pt not released until cough reflex and respiratory status are present.

Question 49

thoracosopy

Answer 49

Thorascopy: pleural cavity is examined and fluid/tissues obtained for analysis. Under anesthesia. Small incisions made in intercostal space. Fluid is aspirated. Sometimes chest tube is inserted. Usually for pleural effusions, pleural disease, and tumor staging. VATS are visual assisted thoroscopy. Requires obtained consent. Npo. monitor vitals. Pain, respiratory status. Bleeding at site. Sob would be pneumothorax.

Question 50

thoracentesis

Answer 50

Thoracentesis: can be done at bedside. Check ptt. Document fluid that comes out. Should be clear. Procedure aspirates fluid and air from pleural space. For diagnostic or therapeutic reasons. Aspirate for analysis, or just to remove it from the space. Biopsy, or instillation of medication. Study fluid- gram stain culture, acid fast staining, total protein, tryglycerides, differential cell count. Obtain baseline vitals. Pt position should be edge of bed leaning on table. Fluid localizes as base of thorax. Performed under aseptic conditions. Site determined by chest xray. Small airtight dressing is placed over when done. When a large amount of fluid is withdrawn, a three way stopcock helps keep air from entering. If air is in pleural cavity, then site is usually second or third intercostal space. Fluid may be clear, serous, bloody, or purulent. Provides clue to pathology. Bloody can indicate malignancy. Purulent fluid indicates infection. Complications include pneumothorax, tension pneumothorax, subcutaneous emphysema, infection. If large amounts of fluid are aspirated, cardiac distress can occur.

Question 51

pleural biopsy

Answer 51

Pleural biopsy is from pleura, thoracoscopy, pleuroscopy. When pleural exudate of undetermined origin, or culturing tissue to identify TB