The site of origin of the intravascular electrocardiogram recorded from multiorificed intravascular catheters.

Successful retrieval of venous air emboli via central venous catheters requires accurate placement of the distal tip of the catheter. The distal tip of single-orificed central venous catheters can be precisely located using intravenous electrocardiography (IVECG). However, the site of origin of the IVECG complex with multiorificed central venous catheters is not well known. In this study, the site of origin of the IVECG complex deriving from the wire within a multiorificed Arrow Antecubital Central Venous Catheterization Kit, the same Arrow catheter type without wire, and a multiorificed Cook Bunegin-Albin CVP Kit was determined in ten anesthetized dogs. The IVECG was found to originate from the distal portion of the Arrow wire whether the distal tip of the wire was within the distal segment of the Arrow multiorificed catheter, at the tip of the catheter, or protruding several cm from the tip of the catheter. When the Arrow multiorificed catheter (without wire) was used to determine the IVECG, the mean site of origin of the IVECG was 1.7 +/- 1.2 cm (mean +/- SD) proximal to the distal catheter tip. When the Cook multiorificed catheter (without wire) was used to determine the IVECG, the mean site of origin of the IVECG was 2.5 +/- 0.6 cm proximal to the distal catheter tip. Knowledge of the site of origin of the IVECG with the Arrow and Cook multiorificed catheters should permit the distal tips of these catheters to be placed in locations where efficient retrieval of venous air emboli is likely.