Respiratory System

Comprehensive NCLEX-RN Review — Anatomy, Physiology, Pathophysiology, Pharmacology, and Nursing Management

1. Anatomy & Physiology of the Respiratory System

Upper Respiratory Tract

• Nose / Nares / Nasal Septum — filters, warms, and humidifies air
• Sinuses — air spaces within hollow bones of the skull
• Pharynx — nasopharynx, oropharynx, and laryngopharynx
• Eustachian Tubes — maintain pressure in the external and middle ear
• Larynx (Voice Box)
  • Contains two pairs of vocal cords: true cords and false cords
  • Glottis: opening between true cords, covered by epiglottis
  • Vocal cords involved in speech production and cough reflex
  • Surrounded by hyoid bone, thyroid cartilage, cricoid cartilage, and arytenoid cartilage

Lower Respiratory Tract

• Trachea: Connects pharynx/larynx to lungs. The carina is where the trachea divides into right and left primary bronchi.
• Bronchi: Right mainstem bronchus is larger and straighter than the left (3 branches vs. 2 branches) — this is why aspirated objects more commonly lodge in the right bronchus.
• Bronchioles: Small passageways supplying air to the alveoli.
• Lungs: Right lung has 3 lobes (upper, middle, lower); Left lung has 2 lobes (upper, lower) — accommodates the heart.
• Pleura: Inner visceral and outer parietal layers with pleural space between them containing lubricating fluid.

Chest Wall

• Supported by 12 pairs of ribs
• Innervation: phrenic, vagus, and thoracic nerves
• Intercostal muscles: External (inspiration) and Internal (expiration)
• Accessory muscles: Scalene (elevate 1st/2nd ribs), Sternocleidomastoid (raise sternum), Pectoralis and Trapezius (fix shoulders)
• Mediastinum: Space between lungs containing heart, trachea, and esophagus

Alveoli & Air Exchange

Alveoli are the functional units of the lungs where gas exchange takes place. They are lined with surfactant — a phospholipid that reduces surface tension and prevents alveolar collapse.

Lung Volumes & Capacities

2. Respiratory Assessment & Diagnostic Tests

Physical Exam

Adventitious Breath Sounds

Diagnostic Tests

Peak Flow Meter

• Measures maximum speed of expiration (Peak Expiratory Flow — PEF)
• Used to evaluate asthma treatment and progress
• Green Zone: good control; Yellow Zone: caution; Red Zone: medical emergency
• Take 3 readings; record the best one
• Readings are lower when airway is constricted

Incentive Spirometer

• Encourages deep breathing after surgery, pneumonia, atelectasis, neuromuscular disorders
• Inhale only through mouth via mouthpiece; hold breath for 3 seconds; exhale through pursed lips
• Perform at least 10 sustained deep breaths per hour

3. ABG Interpretation & Oxygen Therapy

Oxygen-Hemoglobin Dissociation Curve

The curve describes how readily hemoglobin releases oxygen to tissues. A right shift (O₂ dissociates more readily) occurs with:

• ↑Body temperature
• ↑CO₂
• ↓pH (acidosis)

A right shift is beneficial when tissues need more oxygen (e.g., during exercise).

ABG Normal Values

ABG Interpretation (ROME Method)

Respiratory — Opposite; Metabolic — Equal

• Respiratory Acidosis: pH ↓, PaCO₂ ↑ (hypoventilation)
• Respiratory Alkalosis: pH ↑, PaCO₂ ↓ (hyperventilation)
• Metabolic Acidosis: pH ↓, HCO₃⁻ ↓
• Metabolic Alkalosis: pH ↑, HCO₃⁻ ↑

Oxygen Delivery Systems

Low-Flow Systems (Supplement O₂ in room air)

High-Flow System (Accurate delivery of desired FiO₂)

Artificial Airways

• Types: Oral airway, nasal airway, endotracheal (ET) tube, tracheostomy tube
• If patient needs artificial airway >10–14 days → tracheostomy recommended
• Tube placement verified by auscultation + CXR
• Cuff pressure: maintained <20 mmHg; monitor q8h; too high = tracheal stenosis/necrosis
• ET cuff: remain inflated at all times
• Tracheostomy cuff: may be deflated when patient no longer on mechanical ventilation and can eat/talk

Tracheobronchial Suctioning

• Place patient in semi-Fowler's
• Suction oropharynx and perform oral care BEFORE ET suctioning
• Hyperinflate lungs before and after catheter insertion
• Do NOT apply suction during insertion
• Entire suction process ≤ 10 seconds
• Wait 1–2 minutes between passes
• Bradycardia during suction = vagal stimulation — discontinue, ventilate with 100% O₂
• Tachycardia = agitation/hypoxia — may need antianxiety drugs

4. Chest Tubes & Water-Seal Drainage

Indications: Drain accumulated air or fluid from the pleural space.

• For air: chest tube inserted at 2nd–3rd intercostal space, anteriorly or midaxillary line
• For fluid: chest tube at 8th–9th intercostal space, midaxillary line
• Water-seal system allows escape of air/fluid and prevents re-entry of air

Types of Systems

Nursing Management

Chest Physiotherapy (CPT)

• Includes postural drainage, percussion, and vibration
• Postural drainage uses gravity — position patient with affected area uppermost
• Each position drained for 3–5 minutes
• Percussion: cupped hands, 1 hr before or 2–3 hrs after meals; never on bare skin; avoid spine and neck
• Administer nebulizer/aerosol meds before percussion if ordered
• CI in acute asthma attack or croup

5. Mechanical Ventilation

Indications: COPD, neuromuscular disease, severe neurologic depression, thoracic trauma, open heart surgery — patients unable to maintain adequate O₂ and CO₂ levels.

Ventilator Modes

Ventilator Settings

• Tidal Volume (TV): Based on body weight
• Rate: Preset number of breaths/minute
• FiO₂: Fraction of inspired oxygen (the concentration delivered)
• Sighs: Additional volumes delivered 6–10 times/hour to prevent atelectasis

Ventilator Alarms

Nursing Care for Ventilated Patients

• Monitor for bilateral chest expansion
• Attend to alarms immediately
• Empty vent tubing when moisture collects
• Provide oral care and suction as needed
• Monitor for VAP (ventilator-associated pneumonia) — HOB elevated 30–45°, oral care, daily sedation vacation

6. COPD: Emphysema & Chronic Bronchitis

Emphysema vs. Chronic Bronchitis

Discharge Teaching for COPD

• Avoid crowds and people with known infections
• High protein, high carbohydrate diet with ↑Vitamin C
• Annual flu and pneumonia vaccinations
• Home humidifier (maintain 50–60% humidity)
• No smoking
• High-efficiency air conditioner; avoid carpets
• Pursed-lip breathing: In through nose over 2 seconds, out through pursed lips over 4 seconds — helps slow exhalation, maintain alveolar inflation, prevent collapse

7. Asthma (Reactive Airway Disease)

Pathophysiology: Immunologic/allergic reaction → histamine release → bronchospasm, airway edema, tenacious secretions.

Types of Asthma

Findings

• Irritability, shortness of breath, coughing without infection, chest tightness
• Expiratory wheezing, prolonged expiratory phase
• Diaphoresis, use of accessory muscles
• Respiratory acidosis on ABG
• Decreased V/Q ratio

Status Asthmaticus — Emergency Management

• High-Fowler's position + O₂ as ordered
• Rescue meds: Bronchodilators (beta-adrenergics, theophyllines, anticholinergics); Corticosteroids (IV)
• Periodic SpO₂ and peak flow monitoring
• Chest percussion/PD after bronchospasm reduces
• Increase fluid intake

Preventive Medications

• Prophylactics: Cromolyn sodium (mast cell stabilizer), Montelukast (leukotriene modifier)
• Monoclonal antibodies: Omalizumab (Xolair)
• Desensitization therapy / Allergen immunotherapy

Asthma Prevention & Lifestyle

• Good ventilation; damp dusting; avoid rugs, curtains, stuffed animals
• Avoid natural fibers (wool, feathers); cover pillow with plastic
• Stay indoors during grass cutting/high pollen; don't drive with windows open
• Annual flu vaccine + pneumococcal vaccine
• Best exercise: Swimming
• Pursed-lip and diaphragmatic breathing exercises

8. Pneumonia

Definition: Inflammation of the alveolar spaces of the lung resulting in consolidation as alveoli fill with exudates.

Types & Causative Organisms

Findings & Diagnosis

• Productive cough (greenish/rust-colored), chest pain, rapid shallow respiration, nasal flaring, intercostal retractions
• Dullness to flatness on percussion, possible pleural friction rub, crackles in early stage
• Fever, chills, diaphoresis, tachycardia, cyanosis
• Diagnosis: CXR, ↑WBC, ↓PO₂, sputum C&S

Nursing Care

• O₂ as ordered; auscultate breath sounds q2–4h
• Semi-Fowler's position; monitor ABGs
• Promote secretion removal: deep breathing/coughing, ↑fluids, suctioning, expectorants, aerosol treatments, CPT
• Bed rest on unaffected side (reduces hypoxia)
• Limit visitors; uninterrupted rest periods
• Droplet precautions for staphylococcal pneumonia
• Discharge: pneumococcal + flu vaccination; good nutrition; avoid respiratory infections

9. Tuberculosis (TB)

Pathophysiology: Caused by Mycobacterium tuberculosis — an airborne organism. Once inhaled, it multiplies in the lungs causing inflammation and develops primary tubercles. Tubercles undergo caseation and fibrosis. Upper lobes are often affected. Can disseminate (miliary TB).

High-Risk Groups

Non-Caucasians, homeless, Native Americans, low socioeconomic groups, crowded living conditions, alcoholics, malnourished, immunosuppressed (HIV).

Findings

• Productive cough, yellow mucoid sputum, dyspnea, rales/crackles, hemoptysis
• Anorexia, weight loss, afternoon low-grade fever, night sweats

Diagnosis

• PPD: Screening — ≥10 mm induration positive; ≥5 mm in HIV
• CXR: Shows extent of disease but doesn't confirm active TB
• Sputum AFB: 3 positive samples confirm active disease
• QuantiFERON Gold: Reliable in BCG-vaccinated patients
• Elevated WBC and ESR

Medical Management

Treatment duration: 6–9 months average; longer for HIV patients. Multi-drug regimen prevents resistance. Prophylactic INH for 9–12 months for exposed individuals.

Nursing Care

• Airborne precautions: Negative pressure isolation with 12 air exchanges/hour; N95 respirator for staff
• All specimens labeled "AFB Precautions"
• Patient wears surgical mask when transported
• Risk of transmission ↓ significantly 2–3 weeks after starting treatment
• Sputum culture q2–4 weeks; most negative after 3 months
• Three negative sputum cultures = no longer infectious
• High protein, high carbohydrate diet + vitamins; small frequent feedings; weigh twice weekly
• Promote DOT (Directly Observed Therapy) for non-compliant patients
• Importance of covering mouth/nose when coughing; strict hand washing

10. Pulmonary Embolism (PE)

Pathophysiology: Usually a detached venous thrombus from deep veins of the leg, right heart, or pelvic area. Often affects lower lobes of the lung due to higher blood flow.

Risk factors: Same as DVT (obesity, CHF, MI, pregnancy, smoking, trauma, dehydration, OCPs, prolonged immobility, post-op).

Findings

• Pleuritic chest pain, severe dyspnea, tachypnea
• Rales/crackles, apprehension, tachycardia, hemoptysis
• ↑Temperature, shock symptoms if severe, ↑V/Q ratio
• ↑D-dimer

Diagnosis

CT scan, MRI, pulmonary angiography, PET scan, ↑D-dimer.

Management

• Anticoagulants (heparin → warfarin)
• Thrombolytics (for massive PE with hemodynamic instability)
• Narcotics for pain relief
• Surgery: Embolectomy

11. ARDS, Pneumothorax, & Pleural Effusion

Acute Respiratory Distress Syndrome (ARDS)

Definition: Pulmonary insufficiency in adults with no prior lung disorders. Acute injury to the alveolocapillary membrane → massive inflammation, release of inflammatory mediators, ↑capillary permeability, fluid buildup in alveoli, severe pulmonary edema.

Causes: Sepsis, shock, trauma, burns, smoke inhalation, DIC, fat emboli.

Findings: Dyspnea, cough, tachypnea, intercostal retractions, changes in LOC, tachycardia, pulmonary edema, atelectasis, refractory hypoxemia (inability to improve oxygenation with ↑O₂).

Management: Mechanical ventilation with PEEP, high Fowler's, diuretics, anticoagulants, steroids, CPT.

Pneumothorax

Definition: Partial or complete collapse of the lung due to accumulation of air or fluid in the pleural space.

Findings (Pneumothorax)

• Sternal notch out of midline, diminished/absent breath sounds on affected side
• Decreased chest movement, sudden sharp chest pain, dyspnea
• Hyperresonance on percussion, ↓vocal fremitus
• Weak rapid pulse, anxiety, diaphoresis, ↑pCO₂, ↓pO₂

Management

ET intubation/mechanical ventilation, thoracentesis, chest tube/water-seal drainage, narcotics/sedatives, high Fowler's position.

Pleural Effusion

Definition: Collection of fluid in the pleural space. May be transudative (serosanguinous) or suppurative (empyema).

Causes: Complication of pneumonia, TB, lung abscess, bronchial carcinoma, leukemia.

Findings: ↓/absent breath sounds, pleural pain, dyspnea, dullness on percussion, pleural friction rub, dry cough, pallor, fatigue, fever, night sweats (with empyema).

Management: Thoracentesis, closed chest drainage, antibiotics (systemic or intrapleural), pain management, fibrinolytic enzymes (trypsin).

Nursing: With intrapleural medications — turn and reposition q15min. Semi/high-Fowler's, encourage coughing/deep breathing, splint chest.

12. Respiratory Medications

Bronchodilators

Anti-Inflammatory Medications

Leukotriene Modifiers & Mast Cell Stabilizers

Other Respiratory Medications

Guidelines for Inhaler Administration

1. Remove cap and shake well
2. Hold inhaler with metal canister upside down
3. Breathe out fully
4. Open mouth, hold inhaler 2 inches away
5. Press canister and inhale slowly (spacer for children/elderly)
6. Hold breath 5–10 seconds
7. Exhale slowly through nose/pursed lips
8. Wait 1–2 minutes for next dose
9. Rinse mouth after last dose (especially with steroids)
10. Periodically clean mouthpiece

13. Thoracic Surgery

Types of Lung Resection

Pre-Operative Care

• Teach splinting of incision with hands/pillow for turning, coughing, deep breathing
• Demonstrate ROM exercises for affected side

Post-Operative Care

• Auscultate lung sounds q1–2h
• Coughing/deep breathing q1–2h (may continue 6–8 weeks after pneumonectomy)
• Semi-Fowler's position; with pneumonectomy: usually on back or operative side, NOT on unoperative side
• Pain management; chest physiotherapy; high protein diet; adequate fluids; adequate rest
• Avoid people with known infections

14. Pediatric Respiratory Disorders

Variations from Adults

• Narrow airway structures in children <5 yrs → ↑risk of obstruction and infections
• Faster respiratory rate
• Signs of respiratory distress: Nasal flaring, open mouth breathing, retractions, grunting, stridor

Common Pediatric Conditions

Laryngotracheobronchitis (Croup)

• Peak age 1–3 years; usually night onset; paroxysmal laryngeal obstruction
• Hallmark: Inspiratory stridor, hoarseness, barking (seal bark) cough
• Steeple sign on A-P neck X-ray
• Management: Cool mist, nebulized epinephrine, steroids, avoid cough suppressants

Epiglottitis (Medical Emergency)

• Life-threatening bacterial infection (H. influenzae type B); peak age 3–7 years
• Hallmark: High fever, inspiratory stridor, muffled voice, drooling, TRIPOD position
• DO NOT examine epiglottis or obtain throat culture — can precipitate complete airway obstruction
• Management: Maintain airway (may need ET intubation or tracheostomy), cool humidified O₂

RSV Bronchiolitis

• Peak age 2–8 months; occurs in almost every child <2 years
• Wheezing, prolonged expiration, tachypnea, nasal flaring, retractions
• Contact + droplet precautions; Ribavirin (pregnant nurses should not administer); Palivizumab (monoclonal antibody)

Cystic Fibrosis

• Autosomal recessive disorder of exocrine glands; abnormal Cl⁻/Na⁺ transport → thick secretions
• Most common in Caucasians
• Diagnosis: Pilocarpine iontophoresis sweat chloride test (↑Na⁺ and Cl⁻ in sweat)
• Pancreatic: Steatorrhea, meconium ileus, failure to thrive — give pancreatic enzymes with meals
• Respiratory: Thick secretions → obstruction, air trapping, atelectasis, cor pulmonale — CPT 4×/day, Pulmozyme, flutter device, huffing, avoid cough suppressants
• Electrolytes: Salty sweat → add salt to meals; hyponatremia risk in hot weather
• Males are sterile; females can conceive with difficulty

Tonsillitis & Tonsillectomy

• Tonsils: Palatine (paired, anterior — removed in tonsillectomy); Pharyngeal/adenoids (single, posterior)
• Post-tonsillectomy care: Position side/abdomen until awake; ice collar; clear cool non-citrus non-red fluids; no straw; avoid coughing; monitor for hemorrhage (frequent swallowing, tachycardia, vomiting bright red blood)

15. NCLEX Priority Concepts — Respiratory

Respiratory System — Comprehensive Summary Table