Detailed Study Guide for the Respiratory System N225

Learning Objectives for Respiratory System Assessment

The fundamental goals for studying the respiratory system in N225 include describing the structure and functions of the airways, alveoli, lungs, and pleura. Students must understand the mechanics of breathing and demonstrate the ability to obtain an accurate history of the respiratory system. Furthermore, the objective is to correctly perform a physical assessment of the respiratory system, discuss risk factors for respiratory disease, and identify risk reduction and health promotion strategies.

Anatomical Landmarks of the Anterior and Posterior Thorax

Proper identification of thoracic landmarks is essential for accurate assessment. Anteriorly, key landmarks include the clavicle and the suprasternal notch. The sternum consists of the manubrium, the manubriosternal angle (commonly known as the angle of Louis), the body of the sternum, and the xiphoid process at the inferior aspect. The angle of Louis is continuous with the second rib and marks the site of the tracheal bifurcation. The costal cartilage connects the ribs to the sternum, and the costochondral junction is the point where the ribs meet the cartilage. The costal angle is typically less than $90^\circ$ where the right and left costal margins meet the xiphoid process. Intercostal spaces are named for the rib above them; for example, the $2nd$ intercostal space is below the second rib. Other landmarks include the costal margin and the dome of the diaphragm.

Posteriorly, landmarks include the vertebra prominens (the spinous process of $C7$ ), the spinous process of $T3$ , and the inferior angle of the scapula, which usually aligns with the $7th$ or $8th$ rib. The lower border of the thoracic cage reaches the spinous process of $T12$ and the $12th$ rib. Reference lines used for documentation and localization include the midsternal line, the midclavicular line (bisecting the center of the clavicle), and the anterior axillary line on the front. On the side, the midaxillary line is used, while the posterior view utilizes the vertebral line, the scapular line, and the posterior axillary line.

Anatomy of the Lungs, Pleurae, and Tracheobronchial Tree

The respiratory system is divided into the upper and lower airways. The tracheobronchial tree includes the trachea, which bifurcates into the right and left main bronchi. The acinus is the functional respiratory unit consisting of the bronchioles, alveolar ducts, alveolar sacs, and alveoli where gas exchange occurs. The interalveolar septum separates individual alveoli. The lungs are divided into lobes: the right lung has three lobes (Right Upper Lobe or RUL, Right Middle Lobe or RML, and Right Lower Lobe or RLL), while the left lung has two lobes (Left Upper Lobe or LUL and Left Lower Lobe or LLL). On the anterior view, the horizontal fissure separates the RUL from the RML at the $4th$ rib, and the oblique fissures separate the upper/middle lobes from the lower lobes, ending at the $6th$ rib at the midclavicular line. Posteriorly, the lungs extend from the apices at $C7$ down to $T10$ (or $T12$ on deep inspiration), with the oblique fissure starting at $T3$ .

The pleurae are serous membranes that form an envelope between the lungs and the chest wall. The visceral pleura lines the outside of the lungs, dipping into the fissures, while the parietal pleura lines the inside of the chest cavity and upper surface of the diaphragm. The space between them contains a small amount of lubricating fluid. The costodiaphragmatic recess is an extension of the pleura that extends about $3\,cm$ below the level of the lungs.

Mechanics of Breathing

Breathing is an automatic process controlled by the respiratory center in the brainstem. The primary muscle of inspiration is the diaphragm. During inhalation, the diaphragm contracts and moves downward, and the intercostal muscles lift the ribs and sternum, causing the thorax to expand and creating negative pressure that draws air into the lungs. During exhalation, the process is largely passive; the muscles relax, the chest contracts, and the diaphragm moves upward, pushing air out of the lungs. Evaluation of breathing involves observing the rate, rhythm, depth, and effort required.

The Health History and Symptom Assessment

Initial questioning regarding the respiratory system should be broad to capture all potential issues. Common or concerning symptoms include shortness of breath (dyspnea), wheezing, cough, chest pain, and blood-streaked (hemoptysis) or purulent sputum.

Dyspnea of sudden onset may indicate life-threatening conditions such as anaphylaxis, pulmonary embolism, or spontaneous pneumothorax, as well as anxiety. Wheezes suggest partial airway obstruction from tissue inflammation, a foreign body, or asthma. Coughs should be assessed for duration: Acute is defined as less than $3$ weeks, subacute is between $3$ to $8$ weeks, and chronic is longer than $8$ weeks. Sputum quality should be noted as mucoid, purulent, or foul-smelling.

Chest pain can have various etiologies. Cardiac causes include pericarditis, angina pectoris, myocardial infarction, and dissecting aortic aneurysm. Respiratory causes include bronchitis and pneumonia. Gastrointestinal causes include reflux esophagitis, esophageal spasm, gastritis, and biliary colic. Musculoskeletal causes include cervical arthritis, costochondritis, and herpes zoster. Anxiety can also cause chest pain through unknown mechanisms.

Past history should include prior respiratory problems, surgeries, allergies, results of TB skin testing, recent chest x-rays, and immunization status for influenza, pneumococcal, and varicella zoster. Family history identifies risks for lung infections, lung cancer, asthma, or cystic fibrosis, as well as history of secondhand smoke. Lifestyle and personal habits assessment involves tobacco use, recreational drugs, environmental hazards, medication use (prescription, OTC, supplements), and use of oxygen or nebulizers.

Physical Examination: Inspection and Palpation

The physical examination begins with a general survey of respiration, noting the patient's color, facial expression, level of consciousness, and use of accessory muscles like the sternocleidomastoids, scalenes, and abdominal muscles. A patient in the tripod position (leaning forward with arms braced on knees) signifies respiratory distress.

Inspection involves checking the shape and symmetry of the chest wall. Abnormalities include Barrel Chest (equal anteroposterior-to-transverse diameter), Pectus Carinatum (pigeon breast, where the sternum protrudes), and Pectus Excavatum (funnel chest, where the sternum is sunken). The costal angle and retraction or bulging of intercostal spaces are also observed.

Palpation begins with the trachea, which should be midline. The chest wall is palpated for tenderness, masses, or crepitus (a crunchy sensation caused by air under the skin). Symmetric chest expansion (excursion) is tested by placing hands at the base of the chest ( $8th$ to $10th$ rib posteriorly or costal margin anteriorly) with thumbs about $5\,cm$ ( $2\,in$ ) apart; the thumbs should move apart symmetrically during a deep breath. Tactile Fremitus is assessed by having the patient repeat "99" while the clinician uses the palmar surface of the hands to feel for vibrations. Increased fremitus occurs with lung consolidation (e.g., pneumonia), while decreased fremitus occurs when vibrations are obstructed (e.g., pneumothorax or obstructed bronchus).

Physical Examination: Percussion

Percussion helps determine the density of the underlying lung tissue. The clinician percusses over intercostal spaces from the apices downward, comparing sides. Resonance is the low-pitched, clear, hollow sound of healthy lung tissue. Hyperresonance is a lower-pitched, booming sound found in emphysema or pneumothorax. Dullness is a soft, muffled thud suggesting abnormal density as seen in pneumonia, pleural effusion, atelectasis, or tumors. Flatness is a high-pitched, short sound heard over bone (like the scapula) or dense muscle (like the thigh). Tympany is a loud, high-pitched musical sound found over gastric air bubbles or large pneumothoraces.

Characteristics of percussion notes:

Flatness: Soft intensity, High pitch, Short duration (e.g., Thigh).
Dullness: Medium intensity, Medium pitch, Medium duration (e.g., Liver).
Resonance: Loud intensity, Low pitch, Long duration (e.g., Healthy lung).
Hyperresonance: Very loud intensity, Lower pitch, Longer duration (e.g., COPD).
Tympany: Loud intensity, High pitch, Longer duration (e.g., Gastric air bubble).

Physical Examination: Auscultation

During auscultation, the patient should sit leaning forward and breathe deeply through the mouth. The diaphragm of the stethoscope is used to listen to one full respiration in each location, comparing sides symmetrically.

Normal breath sounds include:

Bronchial (Tracheal): Heard over the trachea and larynx; high pitch, loud intensity; inspiration is shorter than expiration (I < E).
Bronchovesicular: Heard over major bronchi, between scapulae, and around the upper sternum ( $1st$ and $2nd$ intercostal spaces); moderate pitch and intensity; inspiration equals expiration ( $I = E$ ).
Vesicular: Heard over peripheral lung fields; low pitch, soft intensity; inspiration is longer than expiration (I > E).

Abnormal and Adventitious Breath Sounds

Adventitious sounds are added sounds not normally heard in the lungs. Crackles (Rales) are short, popping sounds heard usually during inspiration, caused by air colliding with deflated airways or fluid in the alveoli. Fine crackles sound like rolling hair between fingers, while coarse crackles sound like ripping Velcro. These are common in pneumonia and heart failure.

Wheezes (Sibilant) are high-pitched, musical, squeaky sounds heard mostly during expiration, caused by air squeezing through narrowed passages (asthma, chronic bronchitis). Sonorous Rhonchi (Wheezes) are low-pitched, moaning or snoring sounds caused by thick secretions or foreign bodies, often clearing with a cough. Stridor is a high-pitched, crowing sound heard loudest in the neck, indicating upper airway obstruction (croup, epiglottitis). A Pleural Friction Rub is a grating, leather-like sound heard during both inspiration and expiration, caused by inflamed pleurae rubbing together (pleuritis).

Transmitted voice sounds are used if abnormality is suspected:

Bronchophony: Patient repeats "99"; normally muffled; abnormal if "99" is heard clearly.
Egophony: Patient says "eee"; normally heard as "eee"; abnormal if heard as "aaa".
Whispered Pectoriloquy: Patient whispers "1, 2, 3"; normally muffled; abnormal if heard clearly.

Pathological Conditions of the Respiratory System

Atelectasis: Collapsed lung section or entire lung due to bronchial obstruction; causes decreased chest expansion on the affected side and dull percussion.
Pneumonia: Infection causing the alveoli to consolidate with fluid, bacteria, and blood cells; characterized by increased fremitus and dull percussion.
Emphysema: Destruction of pulmonary connective tissue and permanent enlargement of air sacs; results in a barrel chest and hyperresonant percussion.
Asthma: Hyperreactive airways causing bronchospasm, edema, and mucus; results in bilateral wheezing.
Heart Failure: Pulmonary congestion due to increased pressure in pulmonary capillaries; results in crackles at the lung bases.
Pneumothorax: Air in the pleural space causing lung collapse; results in hyperresonant percussion and decreased or absent breath sounds.
Pulmonary Embolism: Blockage in the pulmonary artery; results in chest pain and oxygen desaturation.

Health Promotion and Counseling

Tobacco use is a primary risk factor for respiratory and cardiovascular disease. Compared to nonsmokers, smokers have a $2\text{--}4$ times higher risk of coronary artery disease and stroke, a $12\text{--}13$ times higher risk of COPD mortality, and a risk of lung cancer mortality that is $23$ times higher in men and $25.7$ times higher in women.

Tobacco cessation strategies include pharmacotherapy (e.g., Bupropion, Varenicline) and cognitive therapy. The "5 A's" for assessing readiness are: 1. Ask about tobacco use, 2. Advise to quit, 3. Assess willingness to quit, 4. Assist to quit, and 5. Arrange follow-up. The Stages of Change Model includes Precontemplation, Contemplation, Preparation, Action, and Maintenance.

Immunizations are vital for health promotion. The Influenza vaccine is recommended for those with chronic conditions, health care personnel, and nursing home residents. The Pneumococcal vaccine is recommended for all adults over age $65$ , those with chronic illness, and immunocompromised individuals.

Questions & Discussion

Case Study: Caring for the Nguyens

Mai Nguyen, a $76\text{-year-old}$ woman, presents with fatigue, a persistent cough for $2$ weeks, and confusion. Her vital signs are: BP $142/90\,mmHg$ , pulse $94\,beats/min$ , respiration $24\,breaths/min$ (labored), and temperature $99.6^\circ F$ ( $37.5^\circ C$ ) oral. She has lost $7$ pounds in a month, has dry mucous membranes, and is dyspneic with activity. Her initial pulse oximetry is $90\%$ . She is diagnosed with pneumonia and admitted for IV antibiotics.

Question: What additional assessment data would be useful to gather at this time?
Answer: It would be useful to assess her hydration status, specifically looking for skin turgor and intake/output, given her weight loss and dry membranes. A full auscultation for crackles or diminished breath sounds and an assessment of her sputum production would be essential. Mental status exams are needed to track the progression of her confusion.

Question: What is your clinical judgment regarding Mrs. Nguyen's priority health needs?
Answer: Priority needs include improving oxygenation (addressing the $90\%$ pulse oximetry), managing the infection with broad-spectrum antibiotics, and addressing her dehydration and nutritional status. Clearing airway secretions is a high priority since she is unable to cough them up.

Question: Describe how the nurse will perform a focused respiratory assessment for Mrs. Nguyen. What specific assessments will the nurse prioritize?
Answer: The nurse will prioritize auscultation comparing both lungs for adventitious sounds, checking for symmetric chest expansion, and monitoring respiratory effort and rates. From the general survey, the nurse can observe her labored breathing and signs of distress such as use of accessory muscles or tripod positioning.

Question: After 4 days, Mrs. Nguyen is discharged. She asks, "What can I do to make sure I never get that sick again?" How would you answer this question?
Answer: The nurse should emphasize health promotion strategies, including staying up to date with the annual influenza and pneumococcal vaccines. Ensuring adequate hydration, hand hygiene, and monitoring for early signs of respiratory infection (such as a return of the cough or fatigue) should also be discussed.