**3. Performing a percutaneous pericardiocentesis**

## **3.1 Preparation**

Informed consent must be obtained from the patient with capacity. The procedure itself must be explained along with the indication and potential complications (**Box 5**) [12–14].

	- ST segment elevation/premature ventricular contractions (PVCs) suggest epicardial irritation or puncture
	- PR segment elevation/premature atrial contractions (PACs) suggest entry into right atrium
	- Intrapericardial pressure tracing observed (right ventricular pressure waveform suggests entry into right ventricle)

**Box 5.** *Techniques for confirming needle/catheter placement in the pericardial space.*

The procedure should be performed in the catheterisation laboratory either under echocardiographic [15] or fluoroscopic guidance [16]. In emergency settings percutaneous pericardiocentesis in a controlled planned environment may not be possible and the procedure may have to be performed at the bedside under echocardiographic guidance alone.

Monitoring of heart rate, blood pressure and oxygen saturations along with continuous electrocardiographic (ECG) monitoring is required. Echocardiography facilitates needle tip visualisation and confirms entry into the pericardial space. A resuscitation trolley should be available at the bedside to pre-empt life-threatening complications. Furthermore, a sonographer and nurse should be present during the procedure to provide assistance.

#### **3.2 Patient positioning**

The patient should be positioned head-up at a 30–45° angle to allow pooling of the fluid to the inferior surface of the pericardial sac. The objective of patient positioning is to minimise the distance between the skin surface and the target fluid contained within the pericardial space.

#### **3.3 Selecting an entry site**

Prior to creation of a sterile field with a drape, the most appropriate entry site should be determined using echocardiography. The entry site should be the shortest distance from the skin to the pericardial fluid – thus minimising the risk of damage to intervening structures. Once the optimal entry site has been selected, the proceduralist should note the distance in centimetres from the probe to the pericardial fluid. This acts as an approximate guide for the distance in which the needle tip should be inserted to achieve access to the pericardial fluid.

The classical entry site is sub-xiphoid as usually the fluid accumulates along the inferior surface of the pericardial sac under gravity. However, the rise in the use of echocardiographic visualisation has enabled alternative access sites (e.g. apical, parasternal) to be used safely depending on the clinical scenario. Distance to the pericardial space is greater with the sub-xiphoid approach compared to other entry sites and risk of damage to adjacent structures (e.g. liver, peritoneal cavity) is higher, likelihood of iatrogenic pneumothorax is lower compared to an apical or parasternal approach. Recent evidence supports echocardiography-guided entry site selection with numerous observational studies reporting fewer peri-procedural complications compared to a traditional sub-xiphoid approach [12, 13, 15, 17].

#### **3.4 Aseptic technique**

A strict aseptic technique must be adhered to such that introduction of iatrogenic infection into the pericardial space is avoided. The skin around the proposed entry site is first cleaned with aseptic solution prior to the application of a drape to create the sterile field. Additional sterile drapes placed over the lower abdomen and lower limbs reduce risk of inadvertent contamination.

### **3.5 Local anaesthetic**

One percent lignocaine is infiltrated into the skin at entry site. Local anaesthetic should also be injected into the deeper subcutaneous tissues along the proposed route to minimise intra-procedural pain. Care must be taken when applying lignocaine to ensure it is not infiltrated into small intervening blood vessels.

#### **3.6 Access to the pericardial space**

A needle is inserted at a 90° angle to the skin along the planned trajectory. As outlined above, the most common entry point is sub-xiphoid. However, with the advent of more advanced imaging techniques, alternative entry points are increasingly common – particularly in instances of loculated pericardial effusions [18]. The needle is advanced at an angle of 15–30° toward the left shoulder such that it passes beneath the inferior costal margin.

Continuous aspiration should be attempted during insertion to avoid inadvertent entry into vasculature and to confirm entry into the pericardial space. Further local anaesthetic can be infiltrated into the subcutaneous tissues intermittently during entry as additional intra-procedural analgesia.

## **3.7 Approaches for confirming entry into pericardial space**
