Central line guidelines – OUH

Central Vein Insertion Guidelines

Introduction

Central venous cannulation is a procedure associated with significant morbidly and occasional mortality. Most historical prospective studies demonstrate significant morbidity at around 5% of insertions.

It should only be independently undertaken by those with competence to perform it. If in doubt, discuss with a more senior member of the team or arrange supervision during insertion.

The purpose of these guidelines is both to act as a resource and guide safe practice.

Choosing the best approach to the best vein

Choosing the best vein depends on many factors. These are influenced by both the patient characteristics and the purpose of the catheter to be inserted. The following major factors should be taken into account:

  • Bleeding risk
  • Infection risk
  • Risk of pneumothorax
  • Thrombotic risk
  • Risk of stenosis
  • Ease of tunnelling and port access
  • Ease of insertion
  • Clinical stability
  • Experience and skill or operator
  • Availability and expertise in the use of ultrasound screening and X-ray

The major risks are considered further below:

Risk of bleeding

Veins tend to run alongside arteries. This means that arterial puncture is a common risk during vein cannulation. The risk of arterial puncture is greater for the femoral vein than for the internal jugular vein, and less for the subclavian vein. However, this ranking is reversed when the consequences of arterial puncture are considered. The consequences of subclavian arterial puncture (or even tearing of the subclavian vein) can be considerable as the vessels cannot be compressed manually from the outside the body because they lie under the clavicle, leading to a haemothorax in severe cases.

Bleeding into the neck following internal jugular vein cannulation attempts can cause life-threatening consequences such as airway obstruction, although at least these vessels  can be compressed.

The femoral vein is often the best approach in the patient with decreased blood clotting as a low approach below the inguinal ligament rarely causes life-threatening bleeding (a high approach can cause significant retro-peritoneal haematomas). Cannulation of arm veins (basilic, cephalic and brachial) and passage into a central vein is also a useful alternative in this setting.

Risk of infection

Infections are more common in the femoral region than in other common approaches. This is probably due to the proximity of the perineum and groin skin creases. Cannulation of the subclavian vein probably causes less infection than the internal jugular vein. This is perhaps due to the proximity of the latter to the mouth or tracheostomy site in a critically ill patient. The presence of beards and movements of the neck make maintenance of a sterile dressing more challenging.

Infection at the skin entry site is an absolute contraindication for catheter insertion. All central vein catheterisations should be performed as an aseptic procedure accordingly to local infection control protocols.

Risk of pneumothorax

The risk of pneumothorax is greatest in the subclavian area due to the proximity of the pleura to the vein. Most studies report a rate of pneumothorax with this approach in the order of 2–3% (McGee 2003). The pleura can also be damaged during the anterior approach to the axillary vein as it lies a few centimetres beyond the vein in the direction needle movement. This approach is normally performed under real-time ultrasound guidance to reduce this risk. The only study to date using ultrasound guidance reported no pneumothoraces in 194 patients (Sharma 2004). Although less common, attempted cannulation of the internal jugular vein can also cause pleural breach as the pleural reflection can ascend as superiorly into the neck as a variation of normal anatomy.

Risk of thrombosis and embolisation

Of the common approaches, the risk of thrombosis occurring in the vein is lowest in the subclavian vein, slightly higher in the internal jugular vein and particularly high in the femoral. Classically, thrombosis is more likely where there is the combination of low blood flow, turbulence and increased coagulopathy. It is therefore important to avoid small veins and junctions within the venous system.

Having said this, the risk of embolus of any clot also varies with location. For example, thrombosis of superficial veins in the forearm causes mild morbidity, whereas femoral venous thrombosis may cause life-threatening pulmonary embolus.

For this reason, femoral lines should be avoided wherever possible in patients at high risk of deep vein thrombosis.

Puncture of the carotid artery during attempted internal jugular vein cannulation can cause emboli of atherosclerotic tissue into the brain with the severe consequences of a stroke. The presence of a carotid bruit is a worry for this approach. The consequences of arterial emboli from the subclavian and femoral regions are likely to be much less severe to the patient.

Conclusions

  1. In patients with normal bleeding risks, the vast majority of lines put in on AICU and CICU go into the internal jugular.
  2. It is easier to obtain a satisfactory tip position in the right internal jugular than the left. If a patient requires a Vascath for renal support this should be put into the right side for this reason.
  3. If the patient has a coagulopathy or cannot lie flat either:
    • delay insertion and correct the clotting, or
    • consider a femoral approach, or
    • consider a basilic approach
  4. The subclavian and less common approaches should be considered less common approaches and only attempted by those with competence! If time allows they should be discussed with a senior team member before attempting.

The table below describes the common and less common approaches:

Vein cannulated Advantages Disadvantages
Subclavian vein Lower infection riskSuitability forsubcutaneous tunnelling

and port access

Higher bleeding riskHigher pneumothorax risk‘Blind’ procedure that

Is difficult to guide with

Ultrasound (see below)

Internal jugularvein Vein can be seen clinicallyor with ultrasoundConvenient access during

anaesthesia

Right side highest

probability of correct blind

catheter tip placement (important for Vascaths)

Medium infection riskMedium bleeding riskDifficult to tunnel

conveniently

Difficult to dress

Uncomfortable when not

tunnelled

Femoral vein Lower bleeding riskPatient can remain sittingduring insertion Higher infection riskHigher thrombosis riskPoor catheter

performance when

patient sits up

Basilic vein Lower bleeding riskPatient can remain sittingduring insertion

Probable lower infection

risk

Ease of port access

Medium thrombosis riskMedium stenosis risk
Vein cannulated Ideal catheter tipposition Advantages Disadvantages Insertion issues
Axillary vein(anteriorapproach) Lower one-thirdSVCUpper right

atrium

Lower infection riskLower thrombosisrisk

Low pneumothorax risk

Suitability for tunnelling and port access

Medium bleeding risk Should be ultrasound guided through anterior check wall
Axillary vein(lateralapproach) Lower SVCUpper rightatrium Superficial vesselfor cannulationUseful for morbidly

obese patients

Probable higherinfection riskUncomfortable

when not

tunnelled

Approached throughthe armpitLong catheter needed
External jugularvein Lower SVCUpper rightatrium As for InternalJugular veinEasy to cannulate As for InternalJugular vein Can be difficult topass through intosubclavian and

brachiocephalic

veins

Branchial vein Lower SVCUpper rightatrium As for Basilic vein As for Basilic vein Cannulated in midupper arm withultrasound guidance

(Sandhu 2004)

As for Basilic vein

Cephalic vein Lower SVCUpper rightatrium As for Basilic vein As for Basilic vein Cephalic vein oftenthrombosed inlong-term patients

Passage into SVC

frequently difficult

Long catheter needed

Brachiocephalic(orsupraclavicular

approach to

subclavian)

Lower SVCUpper rightatrium Easy access duringanaesthesiaLarge target vein As forsubclavian vein Supraclavicularapproach

Basic technique

http://www.nejm.org/doi/full/10.1056/NEJMvcm055053 (athens login required)

The use of ultrasound

Ultrasound guidance refers to real time imaging in which the tip of the insertion needle is always in view. The use of ultrasound guidance is routine and should be used as per NICE guidance for internal jugular and femoral lines. It may improve the safety profile of other approaches with the caveat that it often requires a high level of ultrasound expertise.

Guidance can be in transverse (needle out of plane) or longitudinal (needle in plane) view.

Longitudinal (needle in plane) imaging allows confident identification of the needle tip. A patient with a short neck can limit is applicability.

When performed correctly, transverse (needle out of plane) imaging also allows confident identification of the needle tip. It is however quite common to mistake the shaft of the needle for the tip in this orientation with traumatic consequences. For this reason, it is important to periodically identify the needle tip during insertion by moving the probe away from you to check that the needle image disappears.

Ultrasound technique video coming soon…

Some more obvious tips concerning ultrasound are:

  • Try to set up so that your eyes, hands, probe and screen are in a straight line
  • There is no need to palpate the artery whilst doing the procedure – in fact it will probably compress the vein
  • Most U/S machines will go into stand-by after a certain time. This is normally at the crucial moment! Make sure your assistant knows how to turn the machine on again.
  • Scan at a big depth to start, then focus in on the structures you are interested in
  • Assess the depth of the vein on U/S and make sure that you insert the needle to an appropriate depth and no more
  • There is no need to use a small “seeker” needle to puncture the vein initially – it will probably cause a haematoma and worsen your view

Where should the catheter tip lie?

This has been the subject of recent debate. Some generalisations can be made however regarding catheter tip position:

  • The vein should be wide with a high blood flow so that drugs are diluted and therefore less likely to cause damage to the vein.
  • The end of the catheter should be in the long axis of the vein rather than abutting the vessel wall, to minimise wall damage and inaccurate pressure readings. Vessel junctions should therefore be avoided.
  • The catheter tip should be beyond the last venous valve in the route of access.

This narrows down the choice for long-term catheters. The tip can lie in the brachiocephalic veins, the upper or lower superior vena cava, the upper or lower inferior vena cava or the upper right atrium. The smaller the vein, the greater is the risk of wall damage.

Safe positioning of catheters inserted from the left side of the chest may be particularly difficult. This is because there are more twists and turns to be negotiated as the brachiocephalic vein enters the SVC. Frequently, the catheter is left too short and the tip abuts the right wall of the SVC immediately as it enters the vein rather than passing down to lie in the long axis of the SVC/RA. This causes pain on infusion of irritant drugs and potentially serious vessel wall damage. It will also cause problems with aspiration of blood and interfere with accurate pressure monitoring from the distal port.

Debate exists as to whether the catheter tip should be allowed to lie inside the pericardium which extends from the heart to the lower SVC and upper IVC. Some argue that the tip should always be positioned outside the pericardium because if vessel wall perforation occurs, then bleeding or fluid infusion into the pericardium will produce cardiac tamponade. This can rapidly kill the patient. There have been repeatedly small numbers of such cases reported in the literature. An alternative view is that the advantages of a more central vein (such as a lesser risk of thrombosis) outweigh this relatively rare complication, and recommend placement in the lower SVC, upper right atrium or upper IVC. A balanced view on positioning needs to be taken for each individual patient.

The pericardial reflection in relation to the SVC is very unlikely to extend above the carina. As long as the catheter tip is not inferior to the carina on an X-ray, it is unlikely to lie within the pericardium.

FIVE EASY STEPS

Securing the new line

A stich in time
A stich in time

 

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s