PULMONARY DIAGNOSTIC PROCEDURES

  • Reference: Urden, L. D., Stacy, K. M., Lough, M. E., & Sanchez, K. (2025). Critical care nursing: Diagnosis and management (10th ed.). Elsevier.

ARTERIAL BLOOD GASES (ABG)

  • Steps for Interpretation of Blood Gas Levels:

    1. LOOK AT THE PaO2 LEVEL: Determine if the PaO2 indicates hypoxemia.

    2. LOOK AT THE pH LEVEL: Evaluate if the pH is acidic or alkaline relative to 7.40.

    3. LOOK AT THE PaCO2 LEVEL: Assess whether the PaCO2 reflects respiratory acidosis, alkalosis, or if it is normal.

    4. LOOK AT THE HCO3− LEVEL: Determine if the HCO3− level suggests metabolic acidosis, alkalosis, or normalcy.

    5. LOOK AGAIN AT THE pH LEVEL: Check if the pH demonstrates a compensated or uncompensated condition.

LABORATORY STUDIES

  • Oxygen Saturation:

    • Normal range: 95% on room air.

    • Related to available hemoglobin.

  • Oxygen Content:

    • Normal value: 20 mL of oxygen per 100 mL of blood.

  • Base Excess and Base Deficit:

    • Normal range: -2 mEq/L to +2 mEq/L.

QUICK QUIZ

  • A patient has a pH of 7.33, a PaCO2 of 37, and a HCO3− level of 20 mEq/L. Interpret these findings:

    • A. Metabolic Acidosis

    • B. Normal Finding

    • C. Metabolic Alkalosis

    • D. Respiratory Acidosis

ANSWER TO QUICK QUIZ

  • Answer: A. The pH indicates acidemia. The PaCO2 is within normal limits. The bicarbonate level is below 22 mEq/L, indicating that the acidosis is metabolic in nature. Therefore, the patient exhibits a metabolic acidosis.

SPUTUM STUDIES

  • Purpose: Performed to identify the presence of infection.

  • Sputum Examined for:

    • Volume

    • Physical Properties

    • Mucopurulence

    • Color

  • Testing Methods:

    • Gram Stain

    • Culture and Sensitivity

  • Sputum Samples Collection: Specific methods for proper collection must be followed.

BRONCHOSCOPY

  • Indications: Used for diagnostic and therapeutic purposes.

  • Considerations:

    • Use of topical anesthetic.

    • Sedation or analgesia provided to the patient.

  • Complications: Include but are not limited to laryngospasm, bronchospasm, epistaxis, and other potential complications.

THORACENTESIS

  • Indications: Situations requiring pleural fluid sampling or treatment.

  • Procedural Considerations:

    • Patient positioning is critical for success and safety.

  • Complications: Include pain at the site, risk of pneumothorax, and potential for re-expansion pulmonary edema.

BEDSIDE PULMONARY FUNCTION TESTS (PFT)

  • Indications: Used to assess lung function in various clinical situations.

  • Focus Areas:

    • Lung volumes and capacities.

    • Static and dynamic compliance.

    • Inspiratory muscle strength.

    • Mechanics of breathing.

    • Spirometry: A primary tool for measuring pulmonary function.

VENTILATION/PERFUSION SCANNING (V/Q SCAN)

  • Categories:

    • Normal

    • Indeterminate probability

    • Low probability

    • High probability

CHEST RADIOGRAPHY

  • Anatomical References:

    • Visual assessment of trachea, spinous processes, carina, hilum, aortic knob, and pulmonary arteries.

    • Evaluation of cardiac structures including right atrium and ventricle, as well as diaphragm features and costophrenic angles.

    • Note the presence of tubes, wires, and lines in the radiographic evaluation.

DIAGNOSTIC PROCEDURES NURSING MANAGEMENT

  • Psychological Preparation: Providing information and answering questions to alleviate anxiety.

  • Physical Preparation: Proper positioning of the patient to optimize comfort and safety.

  • Monitoring Patient Responses: Observing for any signs of pain, anxiety, or respiratory distress during and after procedures.

  • Assessment Post-Procedure: Monitoring for complications and providing medication for discomfort as needed.

CAPNOGRAPHY: END-TIDAL CO2 MONITORING

  • Types: Includes Mainstream, Sidestream, Proximal diverting.

  • Basic Principles: Utilization of capnography in critical care settings to monitor ventilatory status.

PULSE OXIMETRY

  • Normal Level: 98% oxygen saturation.

  • Basic Principles: Understanding the physiological limitations and technical limitations of pulse oximetry.

  • Caution: Important to recognize limitations and potential errors in readings.

SUMMARY OF KEY CONCEPTS

  • Laboratory Studies: Includes interpretation of ABG levels focused on PaO2, pH, PaCO2, and HCO3−.

  • Oxygenation Efficiency: Assessed via the degree of intrapulmonary shunting.

  • Sputum Specimens: Importance of rapid identification and treatment of pulmonary infections.

  • Diagnostic Procedures: Understanding the utility of fiberoptic bronchoscopy and thoracentesis as both diagnostic and therapeutic methods.

  • Pulmonary Function Tests: Usage during preoperative assessments, lung mechanics evaluation, diagnosing pulmonary diseases, and monitoring therapies.

  • V/Q Scanning: Indicated when serious alterations in normal V/Q relationships are suspected.

  • Chest X-rays: Critical for diagnosing pulmonary disorders and evaluation of treatment efficacy.

  • Bedside Monitoring: Noninvasive methods for monitoring ventilatory status using capnography and oxygenation using pulse oximetry.