Practical procedures in cardiology

PRACTICAL ASPECTS

Practical procedures in cardiology

assessment of central venous pressure, for example after a fluid challenge, is more useful than a single static measurement. CVP measurement is not helpful in conditions such as pulmonary hypertension, pulmonary embolism and right ventricular myocardial infarction, where right ventricular pressures are often grossly elevated.  Intravenous medications, such as amiodarone, hypertonic saline, inotropes, and potassium chloride, can cause phlebitis if given through a peripheral vein.  Access: when peripheral access is poor.  Dialysis: large-lumen catheters are inserted for veno-venous renal replacement therapy. The subclavian vein is best avoided for dialysis access because of the risk of subclavian vein stenosis, which will complicate future access.  Long-term therapy: for patients who need total parenteral nutrition, chemotherapy or long-term antibiotics (for conditions such as endocarditis and osteomyelitis).  Conduit for temporary cardiac pacing: allows a pacing wire to be inserted into the right ventricle in an emergency situation.

Hitesh Patel Jonathan Byrne

Abstract Cardiology is an acute medical speciality in which decisive and prompt treatment along with close monitoring are required to improve outcomes for patients. An acute physician must know not only when to undertake an invasive procedure but how to carry it out, and be able to manage any subsequent complications. In this article, four common procedures are discussed: central venous access, temporary pacing wire insertion, pericardiocentesis and intra-aortic balloon pump placement. This article can be used either as an introductory text for a novice or as a refresher guide. Knowledge of aseptic technique and local anaesthetic administration is assumed.

Procedure The relative pros and cons for each of the three commonest veins used for central access are outlined in Table 1.

Keywords central venous access; intra-aortic balloon pump; pericardiocentesis; temporary cardiac pacing

Methods NICE guidance recommends that the internal jugular vein be cannulated under ultrasound guidance, which minimizes damage to local structures and arterial puncture. If this is unavailable, cannulation should be undertaken using anatomical landmarks (Figure 1). Lines come in two different lengths: 16-cm lengths should be used for the right internal jugular and 20-cm lengths for left internal jugular, left subclavian and femoral access.

Cardiology is an acute medical speciality in which decisive and prompt treatment along with close monitoring are required to improve patient’s outcome. An acute physician must know not only when to undertake an invasive procedure but how to carry it out, and be able to manage any subsequent complications. In this article, four common procedures are discussed: central venous access, temporary pacing wire insertion, pericardiocentesis and intra-aortic balloon pump placement. This article can be used either as an introductory text for a novice or as a refresher guide. Knowledge of aseptic technique and local anaesthetic administration is assumed.

Ultrasound: veins can be cannulated using real-time ultrasound. In contrast to arteries, veins are non-pulsatile and compressible. However, in the presence of deep venous thrombosis, the vein will not collapse with pressure that is normally sufficient to deform an artery.

Central venous access Central venous access is obtained using the femoral, subclavian or jugular vein. Peripherally inserted central catheters (PICC) lines are inserted via the cephalic or basilic vein, or the external jugular vein. The advantage of peripheral access is that the target vessel is easily accessible, visible and ballotable. Disadvantages include valves in peripheral veins, which can obstruct the passage of a catheter into a central vein.

Internal jugular: this is best cannulated at the apex of a triangle in the anterior neck between the sternal and clavicular heads of the sternocleidomastoid muscle immediately above the clavicle. The needle should be inserted at a 30-degree angle, aiming for the ipsilateral nipple, whilst the fingers of the other hand cover the more medial carotid artery pulse. If possible, the right internal jugular should be used e this has a straighter and shorter course than the left.

Indications  Monitoring of central venous pressure: central venous pressure (CVP) is a measure of right atrial pressure. Dynamic

Subclavian: this can be cannulated with a supraclavicular or infraclavicular approach, though the latter is more common. Using the infraclavicular approach, a needle is introduced 1 cm below and lateral to the junction of the medial and middle third of the clavicle, at a 20-degree angle to the coronal plane, aiming for the suprasternal notch (medially and upwards). Ideally, the needle is advanced to the clavicle and then ‘walked’ down into the gap between the clavicle and the first rib where the subclavian vein can be found. Care must be taken during cannulation to avoid injury to the pleura (posterior) and the subclavian artery (posterioresuperior).

Hitesh Patel MRCP is a Specialist Registrar in Cardiology on the South West Thames rotation, London, UK. Competing interests: none declared. Jonathan Byrne PhD MRCP is a Consultant Cardiologist at King’s College Hospital, London, UK. Competing interests: none declared.

MEDICINE 38:10

577

Ó 2010 Elsevier Ltd. All rights reserved.

PRACTICAL ASPECTS

Risks and benefits of the different sites of central access Pros/Cons Infection Thrombosis Pneumothorax Dysrhythmia CVP measurement Patient supine Ease in controlling arterial puncture

Femoral Up to 20% Up to 20% Not possible Not possible Not possible Preferable Easy

Internal jugular 1e9% 2e8%