Respiratory week 6

Anatomy and Physiology of the Respiratory System

  • The Pharynx: Divided into three distinct regions:     * Nasopharynx: Extends from the posterior nares to the soft palate. It contains the openings for the right and left auditory (eustachian) tubes.     * Oropharynx: The space located between the soft palate and the base of the tongue. It houses the palatine tonsils (frequently removed in tonsillectomies) and the lingual tonsils found at the tongue's base.     * Laryngopharynx: Passes dorsal to the larynx and connects directly to the esophagus.

  • The Larynx: Formed by nine pieces of cartilage bound by ligaments that prevent collapse.     * Epiglottis: The uppermost cartilage; it closes the top of the larynx during swallowing to direct food/liquids into the esophagus.     * Thyroid Cartilage: The largest piece of cartilage, commonly referred to as the Adam's apple.     * Vestibular Folds (False Vocal Cords): The superior pair of mucous membrane folds; they play no role in speech but close the glottis during swallowing.     * Vocal Cords (True Vocal Cords): The inferior pair of folds that produce sound when air passes over them.     * Glottis: The opening between the vocal cords.

  • The Trachea:     * A rigid tube approximately 4.5 inches4.5\,\text{inches} (11 cm11\,\text{cm}) long and 1 inch1\,\text{inch} (2.5 cm2.5\,\text{cm}) wide.     * Positioned directly in front of the esophagus.     * Encircles by C-shaped rings of cartilage; the open side faces posteriorly to allow esophageal expansion during swallowing.     * Extends from the larynx to the carina (a cartilaginous ridge).

  • The Bronchial Tree:     * Primary Bronchi: Branch at the carina. Supported by C-shaped rings. The right bronchus is wider and more vertical, making it the primary site for aspirated particles.     * Secondary Bronchi: Branch into the lung lobes. The left lung has two (matching its two lobes); the right lung has three (matching its three lobes).     * Tertiary Bronchi: Smaller branches where cartilage becomes irregular.     * Bronchioles: Airways less than 1 mm1\,\text{mm} wide; they lack supportive cartilage and divide into alveolar ducts.     * Alveoli: Clusters called alveolar sacs where gas exchange occurs.

  • The Lungs:     * Right Lung: Shorter, broader, and larger; handles 55%55\% of gas exchange. Contains three lobes (superior, middle, inferior) and two fissures (horizontal and oblique).     * Left Lung: Contains two lobes (superior, inferior) and one fissure (oblique) to accommodate the heart.     * Apex: The top of the lung, extending 1/2 inch1/2\,\text{inch} (1.3 cm1.3\,\text{cm}) above the first rib.     * Base: Rests on the diaphragm.

  • The Respiratory Membrane: The site of air exchange consisting of alveolar epithelium, capillary endothelium, and their joined basement membranes. Alveoli are wrapped in a fine mesh of capillaries for efficient CO2CO_2 and O2O_2 exchange.

Mechanisms of Ventilation

  • Inspiration (Active Process):     * The external intercostal muscles pull ribs upward and outward.     * The diaphragm contracts, flattens, and drops, increasing thoracic cavity size and pressing abdominal organs down.     * Air rushes in to equalize negative pressure.     * Assisted by accessory muscles: Sternocleidomastoid, Scalenes, and Pectoralis minor.

  • Expiration (Passive Process):     * Internal intercostal muscles pull ribs downward as external intercostals relax.     * The diaphragm relaxes and bulges upward against the lung base, reducing thoracic cavity size.     * Air is pushed out of the lungs.     * Assisted by abdominal muscles: External abdominal oblique and Rectus abdominis.

The Aging Respiratory System

  • Physiological Changes:     * Weakened and atrophied respiratory muscles.     * Reduced elastic recoil of lung tissue.     * Deteriorating cilia and decreased cough reflex leading to decreased force of cough.     * Reduced number of alveoli and reduced effectiveness of alveolar macrophages.

  • Clinical Consequences:     * Air trapping.     * Decreased gas exchange.     * Increased risk of respiratory infections.

Data Collection and Physical Assessment

  • Health History: Assess for upper/lower respiratory symptoms, exposures (smoking, environmental), current treatments, and family history.

  • Inspection:     * General: Symmetry, dyspnea, use of accessory muscles, and skin color.     * Chest Shape: Assessment of thoracic configuration.     * Respiratory Patterns:         * Eupnea: Normal rate and rhythm.         * Hyperventilation: Deeper respirations at a normal rate.         * Tachypnea: Increased respiratory rate.         * Bradypnea: Slow but regular respirations.         * Apnea: Absence of breathing (may be periodic).         * Cheyne-Stokes: Gradually faster/deeper respirations followed by slowing and periods of apnea.         * Kussmaul's: Faster and deeper respirations without pauses.

  • Auscultation:     * Compare bilaterally across anterior, lateral, and posterior positions.     * Adventitious Breath Sounds:         * Crackles (Rales): Bubbling, popping, or clicking noises. Best heard during inhalation at lung bases. Discontinuous. Associated with Bronchiectasis, Bronchitis, Pneumonia, or Fibrosis.         * Wheezes: High-pitched whistling sounds, usually during expiration. Continuous. Associated with Asthma, COPD, or airway obstruction.         * Rhonchi: Low-pitched rattling, snoring, or gurgling sounds. Suggests secretions in large airways.         * Stridor: High-pitched variable sound heard over trachea/upper airways; indicates airway obstruction.         * Pleural Friction Rub: Creaking, grating, or rubbing sound heard during inspiration and expiration.         * Diminished/Absent: Reduced or no air movement heard.

Laboratory and Diagnostic Testing

  • Common Labs: Complete blood count (CBC), Arterial blood gases (ABG), D-dimer (for embolism), Culture and sensitivity (Sputum, throat, nasal), Oxygen saturation, and Capnography.

  • Imaging and Procedures:     * Chest X-ray: Visualizes basic structures.     * Computed Tomography (CT) Scan: Detailed cross-sectional images.     * Ventilation-Perfusion (VQ) Scan: Radioactive compound inhaled (ventilation) and injected (perfusion). A "mismatch" indicates a pulmonary embolus (blood clot).     * Pulmonary Angiography: Contrast material injected into pulmonary arteries to detect embolisms or lesions.     * Bronchoscopy: Use of a bronchoscope to view airways and check for abnormalities.

  • Pulmonary Function Tests (Spirometry):     * Tidal Volume (TV): Normal breath (500 mL500\,\text{mL} for both males and females).     * Inspiratory Reserve Volume (IRV): Maximum inhaled after normal breath (Male: 3000 mL3000\,\text{mL}; Female: 1900 mL1900\,\text{mL}).     * Expiratory Reserve Volume (ERV): Maximum exhaled after normal breath (Male: 1100 mL1100\,\text{mL}; Female: 700 mL700\,\text{mL}).     * Residual Volume (RV): Air remaining after full exhalation (Male: 1200 mL1200\,\text{mL}; Female: 1100 mL1100\,\text{mL}).     * Total Capacity: Male approx. 5800 mL5800\,\text{mL}; Female approx. 4200 mL4200\,\text{mL}.

Therapeutic Measures

  • Positioning: Semi-Fowlers and Fowlers positions to optimize lung expansion.

  • Breathing Exercises: Diaphragmatic breathing, pursed-lip breathing, and huff coughing.

  • Oxygen Therapy:     * Tracheal Oxygen: Direct oxygen to the trachea.     * Masks: Simple mask, partial rebreather, nonrebreather, and Venturi mask.

  • Medication Delivery:     * Nebulized Mist Treatment: Inhaled mist medication.     * Metered-Dose Inhaler (MDI):         1. Shake and remove cap.         2. Exhale.         3. Place mouthpiece in mouth.         4. Press canister while breathing in slowly/deeply.         5. Hold breath for 5−10 seconds5-10\,\text{seconds}. (Wait before second puff).     * Spacer: Device attached to MDI to trap medication and facilitate inhalation.

  • Mechanical Aids:     * Incentive Spirometer: Uses volume calibrations, a piston, and flowrate indicator to encourage deep breathing.     * Vibratory Positive Expiratory Pressure (PEP) Device: Uses a stainless steel ball to create vibrations during exhalation to clear sputum.     * Chest Physiotherapy: Percussion and postural drainage.     * High-frequency chest wall oscillation vest: Vibrating vest for secretion clearance.     * Thoracentesis: Removal of fluid from the pleural space.

Advanced Respiratory Interventions

  • Chest Tube Drainage: Allows air or fluid to escape the pleural space using negative pressure.     * System Components:         * Collection Chamber: Collects fluid. Report drainage if bright red or >100\,\text{mL/hr}.         * Water Seal Chamber: One-way drain. Intermittent bubbling is normal; continuous bubbling indicates a leak.         * Suction Control: Regulates suction level.     * Types:         * Wet Suction: Regulated by the height of a water column; monitor for evaporation.         * Dry Suction: Regulated by a suction control dial; monitor suction bellows.     * Nursing Care (Do's): Assess oxygenation, lung sounds, and site dressing (3 sides taped). Keep chamber below chest level. Ensure tubing lacks kinks. Keep emergency equipment (clamps, sterile H2OH_2O, occlusive dressing) at bedside.     * Nursing Care (Don'ts): Do NOT strip or milk tubing (causes high negative pressure). Do NOT clamp the tube. Do NOT lift chamber above chest level.

  • Tracheostomy: Tube inserted into the trachea to maintain patency.     * Components: Outer tube (with flange and/or cuff), inner cannula, pilot balloon, and obturator (used for insertion).     * Variations: Metal tubes, cuffed plastic tubes, or fenestrated (holed) tubes for speaking.     * Nursing Care: Suctioning, cleaning, facilitating communication, and patient teaching.

  • Intubation and Mechanical Ventilation:     * Endotracheal Tube: Features include a 15 mm15\,\text{mm} adapter, pilot balloon, murphy eye, and inflated cuff.     * Invasive Mechanical Ventilation Nursing: Check advance directives. Maintain Head of Bed (HOB) at 30−45 degrees30-45\,\text{degrees}. Provide oral care with chlorhexidine. Suction as needed. Use a team approach.     * Noninvasive Positive-Pressure Ventilation (NIPPV): Indications and advantages for avoiding invasive intubation.

Questions & Discussion

  • Review Question #1: What occurs in response to negative pressure in the thoracic cavity?     * Answer: Inhalation.

  • Review Question #2: Which acid-base imbalance results from impaired respiratory function?     * Answer: Respiratory acidosis.

  • Review Question #3: Which adventitious breath sound is generated by narrowed inflamed airways?     * Answer: Wheezes.

  • Review Question #4: What is the best method to recommend for smoking cessation?     * Answer: All of the above (Nicotine replacement, drug therapy, behavior modification, hypnosis, setting a quit date).

  • Review Question #5: Which interventions can help patients expectorate sputum?     * Answer: Vibratory positive expiratory pressure (PEP) device, room humidifier, and huff coughing.

  • Practice Analysis Tip (NCLEX-PN): The LPN/LVN must verify and process HCP orders and recognize self-limitations, seeking assistance when a task is beyond their scope.