ICU PROCEDURES: Hemodynamic Monitoring

by | Sep 12, 2024 | Nurse Article | 0 comments

ICU PROCEDURES: Arterial Line Insertion and Monitoring, Central Venous Pressure (CVP) Monitoring and Pulmonary Artery Catheter (Swan-Ganz)

ICU procedures like arterial line insertion, central venous pressure (CVP) monitoring, and pulmonary artery catheter (Swan-Ganz) monitoring are critical for hemodynamic management of critically ill patients. These techniques provide real-time data on blood pressure, fluid status, and cardiac function. Below is a detailed explanation of these procedures:

1. Arterial Line Insertion and Monitoring

An arterial line is a catheter inserted into an artery (commonly the radial, femoral, or brachial artery) for continuous blood pressure monitoring and blood sampling.

Procedure for Arterial Line Insertion:

  1. Preparation:
    • Confirm the need for continuous blood pressure monitoring or frequent arterial blood gas (ABG) analysis.
    • Gather sterile supplies: arterial catheter, guidewire, flush solution, pressure transducer, sterile gloves, and local anesthetic.
  2. Patient Positioning:
    • Position the patient with the selected limb extended and supported. The radial artery is the most common site, and the arm should be slightly dorsiflexed.
    • Perform a Modified Allen’s Test to check for adequate collateral circulation if the radial artery is chosen.
  3. Inserting the Arterial Catheter:
    • Clean the insertion site with antiseptic and apply a sterile drape.
    • Administer local anesthetic (e.g., lidocaine) at the insertion site.
    • Insert the catheter over a guidewire using the Seldinger technique:
      1. Insert a small needle into the artery.
      2. Pass the guidewire through the needle.
      3. Remove the needle and advance the catheter over the guidewire into the artery.
    • Remove the guidewire and connect the catheter to a flush system attached to the transducer.
  4. Securing the Catheter:
    • Secure the arterial line with sutures or adhesive strips and apply a transparent dressing.
    • Connect the line to a pressure transducer for real-time monitoring.

Monitoring the Arterial Line:

  1. Continuous Blood Pressure Monitoring:
    • The transducer converts arterial pressure into waveforms displayed on a monitor, providing systolic, diastolic, and mean arterial pressures (MAP).
    • Ensure the transducer is leveled at the phlebostatic axis (4th intercostal space, mid-axillary line) for accurate readings.
  2. Blood Sampling:
    • Use the arterial line to draw blood for arterial blood gas (ABG) analysis or other lab tests without multiple needle sticks.
    • Maintain aseptic technique when accessing the line.
  3. Complications to Monitor:
    • Infection: Ensure sterile handling and routine dressing changes.
    • Thrombosis: Monitor for distal ischemia (e.g., cold extremity, weak pulse).
    • Hemorrhage: Check for signs of bleeding or accidental disconnection.

2. Central Venous Pressure (CVP) Monitoring

Central venous pressure (CVP) monitoring measures the pressure in the thoracic vena cava near the right atrium, reflecting the patient’s fluid status and right ventricular function.

Procedure for CVP Line Insertion:

  1. Preparation:
    • Gather sterile equipment: central venous catheter (usually a multi-lumen catheter), guidewire, introducer needle, flush solution, and sterile dressing.
    • The common sites for insertion include the internal jugular, subclavian, or femoral vein.
  2. Patient Positioning:
    • Place the patient in the Trendelenburg position (head down) to reduce the risk of air embolism and distend the veins.
  3. Insertion of the Central Line:
    • Clean the insertion site and apply a sterile drape.
    • Insert the introducer needle into the chosen vein.
    • Advance the guidewire through the needle into the vein.
    • Remove the needle and pass the central venous catheter over the guidewire.
    • Secure the catheter and connect it to a pressure transducer system.
  4. Confirm Placement:
    • Use chest X-ray to confirm the tip of the catheter is in the superior vena cava near the right atrium (for internal jugular or subclavian insertions).
    • Once confirmed, connect the catheter to the pressure monitoring system.

Monitoring CVP:

  1. Measurement of CVP:
    • CVP reflects venous return and right heart function. Normal CVP ranges between 2–8 mmHg.
    • CVP can guide fluid management:
      • Low CVP (< 2 mmHg) indicates hypovolemia or dehydration.
      • High CVP (> 8 mmHg) suggests fluid overload, right heart failure, or tension pneumothorax.
  2. Interpretation:
    • Use CVP in conjunction with other clinical signs (e.g., urine output, heart rate, blood pressure) to assess fluid responsiveness.
    • Be cautious with high PEEP settings on the ventilator, as they can artificially elevate CVP readings.
  3. Complications:
    • Infection: Strict aseptic technique is required to prevent central line-associated bloodstream infections (CLABSIs).
    • Thrombosis: Watch for signs of deep vein thrombosis.
    • Pneumothorax: If inserted into the subclavian vein, monitor for potential lung puncture.

3. Pulmonary Artery Catheter (Swan-Ganz) Monitoring

A Pulmonary Artery Catheter (Swan-Ganz) is used to measure multiple hemodynamic parameters, including pulmonary artery pressures, cardiac output, and mixed venous oxygen saturation.

Procedure for Swan-Ganz Catheter Insertion:

  1. Preparation:
    • Use a sterile setup, including the catheter, flush system, and pressure transducers.
    • The catheter is typically inserted via a large central vein (internal jugular or subclavian).
  2. Insertion and Advancement:
    • Insert the catheter using the Seldinger technique through a central line introducer.
    • Once the catheter is in the vein, it is advanced through the right atrium into the right ventricle and then into the pulmonary artery.
    • As the catheter is advanced, the pressure waveform will change at each stage, allowing confirmation of its location.
  3. Balloon Inflation:
    • The catheter has a small balloon at the tip that is inflated as it is advanced to help guide it into the pulmonary artery.
    • Once in the pulmonary artery, the balloon can be inflated to measure pulmonary capillary wedge pressure (PCWP), which reflects left atrial pressure.

Monitoring with a Pulmonary Artery Catheter:

  1. Hemodynamic Measurements:
    • Pulmonary Artery Pressure (PAP):
      • Systolic: 15–30 mmHg; Diastolic: 4–12 mmHg.
    • Pulmonary Capillary Wedge Pressure (PCWP):
      • Normal range: 6–12 mmHg.
      • High PCWP indicates left heart failure or fluid overload.
    • Cardiac Output (CO):
      • Measured by thermodilution or the Fick method.
  2. Interpretation of Data:
    • Low CO: May indicate heart failure or hypovolemia.
    • High CO: May occur in conditions like sepsis.
    • High PAP or PCWP: May suggest left ventricular failure or pulmonary hypertension.
  3. Mixed Venous Oxygen Saturation (SvO2):
    • Measured from the pulmonary artery, reflecting the balance between oxygen delivery and consumption.
    • Normal SvO2 is 60–80%. Low SvO2 indicates inadequate oxygen delivery or increased oxygen consumption.

Complications of Swan-Ganz Catheter:

  1. Arrhythmias: Ventricular arrhythmias may occur as the catheter passes through the right ventricle.
  2. Pulmonary Artery Rupture: Rare but serious, particularly with overinflation of the balloon.
  3. Infection: Central venous catheter infections are a risk, requiring strict aseptic technique.

Summary

These ICU procedures—arterial line insertion and monitoring, CVP monitoring, and pulmonary artery catheter (Swan-Ganz) monitoring—are vital for accurate and continuous assessment of a patient’s hemodynamic status. They help guide interventions for fluid management, cardiovascular function, and oxygen delivery in critically ill patients. Close monitoring, prompt interpretation, and managing potential complications are essential for ensuring optimal patient outcomes.