URIs

Respiratory Diagnostics & Upper Respiratory

Respiratory Labs & Diagnostics

Serum Labs

Hemoglobin

  • Definition: Iron-containing pigment of red blood cells (RBCs).

  • Normal Ranges:
      - Male: 14-18 g/dL
      - Female: 12-16 g/dL

Hematocrit

  • Definition: Measures the percentage of total blood volume made up by RBCs.

  • Normal Ranges:
      - Male: 42-52%
      - Female: 37-47%

  • Decreased Levels:
      - Known as “anemia”.
      - Causes include:
        - Bleeding
        - Bone marrow failure
        - Dietary deficiency
        - Renal disease

  • Increased Levels:
      - Known as polycythemia.
      - Note: Hemodilution/dehydration may affect hematocrit level.

Nursing Implications for Hemoglobin & Hematocrit

  • Trends Monitoring: Pay attention to trends in values.

  • Concerns with Anemia: Adequate oxygenation to tissues and vital organs is a concern.

  • Concerns with Polycythemia: Risk of possible thrombosis due to increased blood viscosity.

D-Dimer

  • Definition: This test looks for D-dimer in the blood. D-dimer is a protein fragment made when a blood clot dissolves in the body.

  • Purpose: Often aids in the diagnosis of venous thromboembolism (VTE), disseminated intravascular coagulation (DIC), and pulmonary embolisms (PEs).

Nursing Implications for D-Dimer

  • You may be asked to draw this lab when PE is suspected.

  • Combined Diagnostics: This should be combined with physical assessment of PE symptoms, D-Dimer levels, and CT scans for effective diagnosis.

Sputum Samples

  • Goal: Identify the bacterial, viral or fungal cause of a suspected infection, as well as its antibiotic sensitivities.

  • Indications for Specimen Collection:
      - Clinical signs of infection (e.g., productive cough with purulent sputum).
      - Signs of systemic infection.
      - Fever of unknown origin.

  • Types of Studies:
      - Acid-fast bacilli (AFB) test for Tuberculosis.
      - Culture & Gram Stain for infections.
      - Cytology test.

Sample Collection Procedure for Sputum

  1. Patient Positioning: Upright in a chair or in bed in Fowler position.

  2. Breathing Techniques: Ask the patient to take deep breaths (in through the nose and out through the mouth) to loosen secretions.

  3. Nebulization: A sodium chloride nebulizer can help in loosening secretions.

  4. Sample Collection: Collect the specimen in the designated container and seal it with a lid to prevent contamination and cross-infection.

Pulse Oximetry

  • Definition: Measures the amount of hemoglobin carrying oxygen (analogy: “How full are those buses?”).

  • Normal Levels: A reading of ≥ 95% is considered normal.

Nursing Implications for Pulse Oximetry

  • Decreased Levels Indicate:
      - Hypoventilation
      - Atelectasis, pneumothorax, or other lung problems

  • Usage:
      - Non-invasive method available in intermittent or continuous monitoring forms.
      - Commonly used to titrate oxygen levels in hospitalized patients.

  • Considerations:
      - Ensure no nail polish is on fingers. Can use the earlobe or sometimes the toe for measurement.

Chest X-Ray (CXR)

  • Preparation: Remove any metal objects between the neck and waist.

  • Common Views: The most common views are posteroanterior (PA) and lateral.

CT Scan (Computed Tomography)

  • Features:
      - Provides cross-sectional imaging of structures.

  • Sedation Requirements: May require sedation due to the need for the patient to lie still and for those with claustrophobia.

  • Technical Aspects:
      - Hard table involved; the scanner revolves around the body while making clicking noises.
      - Options for imaging “with or without contrast”.

  • With Contrast Considerations:
      - Assess BUN/Creatinine levels prior to administration.
      - Check for allergies to shellfish (iodine-based contrast).
      - Patients may feel a “warm flush” sensation.
      - Advise to force fluids afterward to encourage renal clearance.

Magnetic Resonance Imaging (MRI)

  • Purpose: Used to assess lesions that are difficult to evaluate with CT scans (e.g., lung apex) and to differentiate between vascular and nonvascular structures.

  • Contrast Medium: Uses a contrast medium that is not iodine-based.

  • Sedation Needs: If the MRI is closed, sedation may be required for patients with claustrophobia.

  • Metal Considerations: Any metal must be removed prior to the procedure.

Positron Emission Tomography (PET) Scan

  • Definition: Uses a radioactive substance (tracer) to identify lung disease or cancer.

  • Comparison with Other Imaging: While CT and MRI focus on the structure, PET scans look at body function, including:
      - Blood flow
      - Use of oxygen
      - Sugar uptake.

Pulmonary Function Test

  • Objective: Evaluate lung function by measuring air movement within the lungs.

  • Performed By: Typically conducted by a respiratory therapist.

Lung Volumes: Measurement Overview

  • Total lung capacity: 6,000 mL

  • Maximum possible inspiration: 5,000 mL

  • Inspiratory reserve volume: 3,000 mL

  • Expiratory reserve volume: 1,000 mL

  • Maximum voluntary expiration: Varies

  • Residual volume: Varies

  • Inspiratory capacity: Varies

  • Vital capacity: Varies

  • Functional residual capacity: Varies

  • Tidal volume: Varies

Tuberculin Test (TB Skin Test/Mantoux Test)

  • Procedure:
      - Inspect and palpate the site under visual inspection.
      - Assessment includes measuring erythema (reddening) and induration (hard, dense formation).

TB Risk Factors

  • Environment:
      - Tight living quarters (e.g., long-term health care facilities, homeless shelters, prisons, etc.).
      - Below or at the poverty line, including the homeless.
      - Refugees from high TB incidence countries.

  • Health Factors:
      - Compromised immune systems (e.g., HIV).
      - Substance abuse (IV drugs, alcohol).
      - Children less than 4-5 years old with weak immune systems.

Reading and Interpreting the TB/Mantoux Test

  • Timing: The test must be read within 48-72 hours. The patient must return to have the test read; if not, it must be repeated.

  • Results Interpretation:
      - A positive result indicates exposure to TB but does not confirm active infection.
      - Distinction between latent and active infections requires further tests like chest x-rays and sputum cultures.

  • Induration Assessment:
      - Measure for induration in millimeters (mm), not redness.

  • Positive Result Guidelines:
      - 15 mm or more: Positive in all individuals, regardless of risk factors.
      - 10 mm or more: Positive in immigrants, IV drug users, those living or working in tight quarters, and children under 4.
      - 5 mm or more: Positive in HIV-positive individuals, those with TB contact, organ transplant patients, or immunosuppressed persons.

Common Upper Respiratory Problems

Epistaxis (Nosebleeds)

  • Causes:
      - Irritation, trauma, infection, foreign bodies, tumors.
      - Hypertension or blood dyscrasias.
      - Drug-induced (e.g., chemotherapy, anticoagulants).
      - Anterior vs. posterior classification needed.

Nursing Care for Epistaxis

Anterior Nosebleeds:

  • Positioning: Position the patient upright, lean forward, and pinch nostrils together.

  • Reassurance: Calm and reassure the patient.

  • Methods: Apply lateral pressure and ice.

  • Packing: Loose packing may be employed.

  • Instructions: Avoid blowing the nose post-care.

Posterior Nosebleeds:

  • Emergency Treatment: These may require hospitalization.

  • Assessment: Continuous assessment of respiratory status.

  • Supportive Care: Includes humidification, oxygen, bed rest, pain management, and oral care.

  • Patient Teaching:
      - Advise using saline spray and humidification.
      - Avoid aspirin or NSAIDs.
      - Caution against strenuous activities.

Upper Respiratory Infections (URI)

  • Common URIs include: Tonsillitis, Influenza, Rhinitis, Laryngitis, Pharyngitis, and Sinusitis

URI Key Highlights

  • Pharyngitis:
      - Viral causes are most common in adults (70%) including the common cold and flu.
      - Fungal infections (e.g., candidiasis) account for about 10%.
      - Bacterial infections commonly involve β-hemolytic Streptococcus (20%).
      - If untreated, complications can include:
        - Acute glomerulonephritis (7-10 days post-infection).
        - Rheumatic fever (3-5 weeks post-infection).

  • Influenza:
      - Caused by viral agents A, B, or C.
      - Flu vaccine is recommended annually for high-risk groups.
      - Most common complication: pneumonia.

  • Rhinitis:
      - Distinction: Allergic vs. Viral/Bacterial.
        - Allergic: Hay fever/allergies.
        - Viral: Common cold appearance.

  • Sinusitis:
      - Most commonly viral in origin, may become bacterial if symptoms persist beyond 14 days.

  • Laryngitis:
      - Often viral; can result from vocal abuse (inflammatory processes).

  • Tonsillitis:
      - Can be either viral or bacterial; group A strep is a common bacterial cause.
      - Surgical intervention may be needed (T&A = tonsillectomy and adenoidectomy).

Nursing Management for Upper Respiratory Infections

  • Management strategies vary depending on the type of -“itis”:
      - Remove the causative agent if bacterial (use of antibiotics).
      - If viral, employ supportive measures only (rest, fluids) and medications including:
        - Antihistamines
        - Analgesics
        - Decongestants for sinusitis
        - Anti-virals (e.g., Tamiflu)

  • Focus of Care: Treat symptoms effectively!