To begin, palpate the thoracic wall for the point of maximal intensity (PMI), and clip a large area of fur centered on that
spot. Select a location for catheter introduction in the intercostal space nearest the apex beat (typically the seventh or
eighth intercostal space). Perform an initial scrub before injecting the lidocaine. Use a 3-ml syringe with a 25-ga, ¾-in
needle to infiltrate 1 to 2 ml of lidocaine to create a local block cranial to the rib. We recommend blocking the area where
the pericardiocentesis needle will enter, which is cranial to the rib, to avoid damaging the neurovascular bundle caudal to
the rib. Be sure to infiltrate the skin, intercostal muscle, and pleural lining to completely desensitize the region and ensure
patient comfort throughout the procedure. Administer a bleb of lidocaine subcutaneously, and slowly insert the needle until
you meet resistance from the pleural lining. Then inject lidocaine as you slowly withdraw the needle along the tract.
Once the needle is withdrawn, perform a full surgical prep of the area, using the subcutaneous lidocaine bleb as the center.
Some clinicians use a skin-marking pen to mark the injection site to ensure accurate catheter placement should the lidocaine
bleb not persist. When this technique is used, sedation is rarely needed unless the patient is particularly fractious.
A 14-ga, 5-in catheter is ideal for most medium- to large-breed dogs, but you can use a 16-ga, 2½-in catheter in smaller dogs
or if a larger catheter is not available. Glove and use a scalpel blade to carefully add holes in the catheter's sides near
its tip (Figure 1). This will maximize flow if the catheter tip becomes occluded. Be sure you don't produce any burrs.
1. Carefully making two or three notches in the catheter sides with a scalpel blade can greatly increase fluid flow and reduce
the likelihood of obstruction. Be sure you do not produce any burrs in the process.