Central Venous Pressure (CVP)

(4th intercostal space & midaxillary line)

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• Medical condition requiring intravenous access to central circulation
• Post-operative monitoring for management of fluid volume status
• Hypovolemic shock
• Burns or trauma requiring rapid fluid resuscitation
• Total parenteral nutrition (TPN)
• Monitoring of central venous pressure (CVP)

• Understanding of procedure
• History of heart failure, COPD, head injury, cerebral bleeding risk
• Allergies to iodine, tape, Latex^®, ointments

• Informed consent (principle of autonomy)
• These are contraindications for positioning the patient in Trendelenburg position.
• Guide for selection of supplies to prevent allergic reaction

Steps

1. Wash hands.

2. Prepare pressurized and heparinized flush solution. (See procedure under Hemodynamic Principles).

3. Flush pressurized closed transducer tubing with luer-lok connections and ports.

4. Don sterile gloves, protective gown, and mask.

5. Assist with skin preparation.

6. Position patient in Trendelenburg position.

7. Assist physician or advanced practice  nurse with flushing central venous catheter ports with sterile solution and capping ends with luer-lok caps.

[Physician will apply topical anesthetic to insertion site, then use a needle and syringe with negative pressure to access the subclavian or internal jugular vein.  Next the physician will insert a guidewire through the needle, remove the needle, then insert a dilator “over” the guidewire.  Last, the physician will remove the dilator and insert the central venous catheter “over” the guidewire.  Then the guidewire is removed.]

8. The patient will be instructed to take a deep breath and hold it prior to the insertion procedure.

9. The central venous catheter will be inserted a 3 – 5 inches.

10. Pressure tubing will be connected to distal port of central venous catheter as soon as the catheter has been inserted.

11. Level the transducer with the patient's phlebostatic axis and "zero" the transducer. (See Hemodynamic Principles.)

12. Monitor cardiac  monitor and hemodynamic waveform during catheter insertion.

13. Observe waveform and perform a dynamic response test (square wave test).

14. Record central venous mean pressure and waveform.

15. Apply sterile transparent occlusive dressing over insertion site.

Rationales

1. Prevention of nosocomial infections.

2. 1-2 units heparin/mL reduces risk of catheter occlusion through thrombosis.

3. Removal of ALL air bubbles promotes better waveforms and reduces danger of air embolism.

4. Arterial line insertion is a sterile procedure

5. Reduce normoflora microbes at insertion site.

6. Inflates internal jugular vein making it an easier target during catheter insertion. Decreases risk of air embolism.  (See contraindications above.)

7. Reduces risk of air embolism during insertion.

[Sterile technique is used during the insertion procedure.  The physician and nurse should be wearing sterile gowns and masks.  The physician or whoever is performing the insertion must wear sterile gloves while working with the catheter.  The patient will be draped with a sterile field by the physician.  During insertion, it is the responsibility of the nurse to monitor the patient’s tolerance of the procedure and assess for any complications like dyspnea (possibly due to pulmonary embolism, pneumothorax) or tachycardia (due to stress, hypovolemia) or dysrhythmias (catheter placement).]

8. Increased intra-thoracic pressure reduces the risk of air embolism during exchanges of dilator and catheter over guidewire.

9. The distal tip of the central venous catheter should be located in the superior vena cava.

10. This allows monitoring of CVP once catheter is in place.

11. Phlebostatic axis approximates the level of the right atrium for establishing pressures in the circulatory system which enhances accuracy of readings.

12. Assesses how patient tolerates procedure and provides evidence of catheter placement.

13. Test for dampness of waveform.

14. Provides baseline data about right atrial (CVP) pressures.

15. Sterile procedure; occlusive dressing prevents blood stream infections.

(See CVP Waveforms.)

Steps

1. Position patient supine with head-of-bed 0 – 60^o elevation.
2. Check level of transducer with phlebostatic axis.
3. During first assessment of shift, zero transducer to air.
4. Assess waveform for dampness.
5. Maintain tight luer-lok connections and nonvented caps on stopcocks of pressure tubing.
6. Record CVP pressure from the monitor

Rationales

1. Lateral positioning may result in variable pressure readings.  Supine promotes consistency of conditions.  Head-of-bed elevation has not been shown to alter pressure recordings significantly.
2. Insures accuracy of readings.
3. Insures representation of patient's BP on monitor.
4. Dampness may distort systolic and diastolic readings.
5. Prevents risk of air embolism.
6. CVP reflects a mean pressure in the right atrium.

1. Position patient supine with head-of-bed 0 – 60^o elevation.
2. Turn stopcock of water manometer off to patient and fill water manometer up to 20 cm H₂O.
3. Align 0 (zero) of water manometer with phlebostatic axis.
4. Turn stopcock of water manometer off to IV solution bag.
5. Encourage the patient to take some normal breaths while the water descends the water manometer to the resting pressure.
6. Read the water meniscus (bottom of water level) during end expiration of the patient's respiratory cycle.
7. As soon as a pressure is read, turn the stopcock of the water manometer off to the water column and flush the IV tubing of any blood backed up in the tubing.  Leave the stopcock in the off position to the manometer when not in use.

1. Lateral positioning may result in variable pressure readings.  Supine promotes consistency of conditions.  Head-of-bed elevation has not been shown to alter pressure recordings significantly.
2. Be careful not to overfill water manometer!
3. Equalizes pressure between water manometer with right atrium.
4. Opens water manometer to patient's central venous circulation.
5. Patient's breathing allows water manometer to equalize pressure.
6. On a water column, the water line is not flat but curved downward creating a meniscus.  The bottom of the meniscus represents the true water level.  The end expiration of the patient's respiratory cycle is the point at which intrathoracic pressures are not affected by breathing.
7. If the stopcock is not turned off to the water manometer when the manometer is moved above the patient, air embolism can occur.  Any blood in the central catheter can generate clot formation and eventually occlude the catheter or (worse) cause a pulmonary embolism.

• Central Venous Pressure:          2 – 5 mm Hg   (3 – 8 cc H₂O)   [This is actually a mean pressure of the right atrium.]

Guidelines for the Prevention of Intravascular Catheter-Related Infections

1. Hand Hygiene:  Thorough handwashing prior to insertion or handling of central venous catheters will reduce risk of nosocomial infections.

2. Maximal Barrier Protection:  The insertion of a central venous catheter should be done under sterile (surgical asepsis) conditions.  The clinician inserting the catheter should wear mask, cap, sterile gloves, and sterile gown.  The patient should be draped in a sterile field around the insertion site.  Assistants (e.g., nurses) should wear masks, protective gowns, and gloves while in the area–if the nurse will be working with the sterile equipment or supplies, the nurse should wear sterile gown, mask, cap, and sterile gloves too.

3. Chlorhexidine Skin Antisepsis:  Chlorhexidine has been shown to reduce more skin normal flora than povidone-iodine or alcohol as a skin disinfectant prep prior to insertion of a central venous line.

4. Optimal Catheter-Site Selection:  Rates of catheter-related bloodstream infections are lowest among catheters inserted into subclavian vein compared to internal jugular vein.  Femoral vein insertions should be avoided if possible due to the high rates of bloodstream infections associated with the inguinal area.

5. Daily Medical Review of Necessity of Catheter:  The medical physician should review daily the need for a central venous catheter with the goal of early removal as soon as the patient no longer needs the catheter.  The longer a catheter is retained, the higher the probability of bloodstream infection.  The nurse can bring this to the physician's attention during rounds as to whether any critical interventions like TPN or hemodynamic monitoring is occurring that needs a central venous catheter.

6. Replacement of Catheter:  Recent evidence suggests that the rate of infections are not significantly different when catheters are replaced every 72 hours or less. 

Bundle of Practices Related to Nursing Care:

1. All-Inclusive Catheter Cart or Kits:  Having a cart or kit that has all necessary equipment for procedures reduces the risk of contamination of equipment when additional items are added to a sterile field.

2. Hand Hygiene:  For all nursing procedures involving a central venous catheter (changing tubing, adding second infusion line, changing TPN solutions, IV administration of medication) the nursing care should begin with thorough hand washing with soap and running water to reduce the risk of nosocomial infections from other sources.

3. Site Care:  Maintain a well adhesive transparent dressing over central venous catheters.  Cath cares should involve scrubs of site with chlorhexidine during dressing changes.  Transparent dressings only need to be changed every 7 days.  Gauze dressings should be changed every 48 hours.  Anytime a dressing is damp, soiled, or coming loose, then it should be changed with a full skin prep prior to application of a new dressing.

4. Line Access:  The less frequently a central line is accessed from one of its ports (hubs), the higher the risk of a bloodstream infection.  Therefore, do not access a central venous catheter except for essential procedures requiring the central line.

5. Scrub the Hub:  When a hub on a central venous catheter infusion line is accessed, evidence does not support chlorhexidine over 70% isopropyl alcohol.  However, the duration of scrubbing the access hub influences the risk.  Performing a twisting scrubbing motion for 30 seconds with a disinfectant significantly reduces bloodstream infections.

6. Replacement of IV Administration Sets (Tubing):  Replacement of central line tubing every 72 hours is not associated with lower infection rates compared to 96 hours.  Replacement of tubing should be done with strict asepsis.  Special infusions like lipids or TPN may require more frequent tubing changes because the fluid medium is a greater risk for infection.

7. Appropriate Staffing and Nursing Workloads:  Evidence has indicated that the higher the nursing workloads or the more inadequate the staffing, the less time that is available for safe management of central venous catheters.

• Encourage patient to drink more fluids.
• Increase IV fluid infusion rate.
• Transfuse blood if indicated.

• Fluid restriction.
• Diuretic to enhance fluid elimination.
• Reduce IV infusion rates.
• Assess urine output to see if there are any obstructions to urine flow or evidence of acute renal failure.
• Assess laboratory work for possibility of renal failure.