Central Lines Flashcards
When do you consider a central line to be “correctly placed”
- If the distal tip of the catheter is at the junction of the superior vena cava and right atrium
- lower risk for clot formation
Indications for central lines (short term)
- Larger IV access to be able to administer fluids and/or blood at a more rapid rate
- IV access when peripheral IV attempts failed
- Monitor central venous pressure (CVP)
- Insert a pulmonary artery (Swan Ganz) catheter
- Can administer vasopressors and inotropes that are contraindicated to administer peripherally
- Temporary emergency hemodialysis
- Place temporary transvenous pacing wires
- Aspirate air embolism from heart
Long term indications for central lines
- Chemotherapy
- Long term antibiotics
- Total parenteral nutrition (TPN)
Complications of central lines
- Infection
- Venous stenosis
- Accidental arterial puncture
- Thrombosis
- Pneumothorax
- Transient arrhythmia during insertion
- Nerve injury
- Air embolism
Signs and symptoms of an air embolism
- Sudden decrease in end tidal CO2
- Sudden increase in end tidal nitrogen
- Hypotension/tachycardia
- Cyanosis
Risk factors for development of air embolism
- During central line placement
2. Surgical site is above the level of the heart -lower BP makes it easier for atmospheric air to enter
Diagnosis of an air embolism
- TEE is the best (most sensitive)
2. Precordial Doppler (good in field avoidance cases)
Treatment for an air embolism
- Flood the surgical field with saline
- Deliver 100% oxygen
- Place of in left lateral Trendelenburg
- Give volume to increase CVP
- Start a central line to aspirate air out
- Support BP
Central line veins in order from easiest path to most difficult path
- Right IJ
- Left subclavian
- Left IJ
- Right subclavian
- Right and left EJ
Advantages of an EJ
It is the most superficial
Disadvantages of an EJ
- “Tortuous path” to SVC, making it difficult to advance a guidewire or long catheters
- Risk of infection due to facial hair and close proximity to respiratory secretions
Why use an EJ?
- Accessed with a regular IV catheter if the patient is a difficult stick
- NOT a legit “central line” due to the path to the R atrium
When does an air embolism become fatal?
In adults, 200-300ml or 3-5 ml/kg
Advantages of IJ
- Great visualization with ultrasound
2. RIGHT IJ provides the easiest catheter pathway to R atrium
Disadvantages of IJ
- Close proximity to carotid artery
- Significant risk of infection
- Risk of pneumothorax
- Uncomfortable for the pt
Advantages of subclavian vein
- Lowest infection rate
- Most comfortable to the pt
* **EASIER IN THE LEFT
Disadvantages to subclavian vein
- Ultrasound guidance is difficult
- Highest risk of pneumothorax
- Bleeding is difficult to control
- Catheter can become compressed between clavicle and first rib (“pinch-off” syndrome)
Advantages of the axillary vein
- Better able to visualize with ultrasound than subclavian
2 Lower chance of accidental arterial puncture - Lower chance of pneumothorax
Advantage of femoral vein
- Easier access in an emergency
Disadvantages of femoral vein
- Risk of arterial puncture
- Highest infection rate
- Risk of venousthromboembolism
- Risk of femoral nerve injury
- Risk of bladder perforation
- Risk of peritoneal perforation
The amount of venous blood returning to the heart (R atrium)
Venous return
Associated with CVP
Adequate venous return = (low/normal) CVP
Normal CVP
Decreased venous return = (low/normal) CVP
Low CVP
Factors that affect venous return
- Volume status (hypovolemia = low venous return)
- Intrathoracic pressure (high pressure/PEEP/PPV = decreased venous return, negative pressure/spontaneous inhalation = increased venous return)
- Vasodilation (increased vasodilation = decreased venous return)
- Patient positioning (reverse Trendelenburg = low venous return, Trendelenburg = high venous return)
Normal CVP
5-12 mmHg
Represents blood pressure inside a central vein
Central venous pressure (CVP)
Why is CVP monitoring important?
- Helps assess pt’s volume status and venous return
2. Can help assess R heart function
Causes and treatments for low CVP
Causes: 1. Hypovolemia 2. Reverse Trendelenburg/sitting/beach chair 3. Vasodilation Treatment: Volume resuscitation
Causes and treatments for high CVP
Causes:
1. Fluid overload
2. Heart failure (cardiac tamponade)
3. Pulmonary hypertension
4. Trendelenburg
5. High intrathoracic pressure (tension PNX)
6. Tricuspid/pulmonary stenosis or regurgitation
Treatments:
1. Restricting intraoperative fluids
2. Administering inotrope (for HF) or diuretic
How does high intrathoracic pressure decrease venous pressure, but increase CVP?
With high intrathoracic pressure, venous return from the legs AND head decrease, pooling in the central veins, increasing CVP
Waves on the CVP waveform
a wave- end diastole, atrial contraction
c wave- early systole, ventricular contraction
x descent- mid systole, atrial relaxation during ventricular systole
v wave- late systole, blood filling in R atrium during relaxation
y descent- early diastole, opening of tricuspid valve, prior to atrial contraction
What is a “cannon wave”
An abnormally tall wave on the CVP waveform, typically refers to tall A waves seen with tricuspid stenosis, but can occur with V waves with tricuspid regurgitation
Causes of cannon waves
- Tricuspid stenosis
- Complete heart block
- Junctional rhythm
An increase in R atrial pressure during the atrial relaxation period
Cannon V
Systole waves with CVP waveform
C, X, V
Diastole waves with CVP waveform
A, Y
Explain the lumens of a triple lumen 7F central line
- One distal 16ga (brown) lumen for CVP
2. Two proximal 18ga (white, blue) lumens for fluid boluses or infusion lines
Explain the lumens of a double lumen 7F central line
Two 16ga ports: brown for CVP (distal)
White for fluids/infusions (proximal)
Types of central lines with an introducer port
- 8.5F Percutaneous Sheath Introducer (PSI)
2. Double lumen 9F MAC catheter
Purpose of introducer port
Required for pacing wires or a pulmonary artery (Swan Ganz) catheter
Advantage: larger lines (8.5 or 9F)
Disadvantage: Less ports
Options for adding more ports to introducer catheter
- Pulmonary artery (Swan Ganz) catheter gives off 3 more ports, 1 for CVP, 1 for infusions and 1 for pulmonary artery pressure monitoring
- Companion catheter can be single or double lumen for infusions and CVP monitoring
- Single Lumen Infusion Catheter (SLIC) just one port for CVP monitoring
Purpose of dialysis central line
Can be as large as 14 F
Used to treat acute problems in patients without long term dialysis access
Central lines for long term therapy
- Peripherally inserted central catheter (PICC) line
- long catheter length = more resistance = slower drip rates - “Tunneled” catheters:
- mediport: must be accessed with needle stick “huber” needle
- broviac: external to body, sterile dressing needs to cover exit site. Higher chance of infection
What should you do when accessing a tunneled catheter?
- May require heparin to prevent blood clots
- Aspirate 10 mls before dosing fluids or drugs
- Flush lines with NS or LR before and after drug administration
