Central venous catheters

Correct positioning of the venous port-a-cath catheter: comparison of intravascular electrocardiography signal from guidewire and sodium bicarbonate flushed catheter

A prospective study comparing the efficacy of wire-conducted intravascular ECG (IVECG) signal and signal from the port with a sodium bicarbonate (NaHCO3) flushed catheter to correctly place a catheter tip was carried out in 100 patients. The correct position of the catheter tip was confirmed as follows: with technique G, the IVECG signal was conducted from a guide wire to identify the tip position. With technique P, the IVECG signal was conducted from the port with a NaHCO3 (0.8 mmol/ml) flushed catheter to ascertain the tip position. Each patient received both technique G and technique P in a randomized sequence. The quality of IV-ECG signals, which included baseline drift, P wave pattern and QRS wave pattern, were assessed for ten seconds. Satisfactory quality of these IVECG signals was observed in all of the patients with technique P and 90 of the 100 patients with technique G, and this difference was significant (P=0.001). There was no obvious difference between the techniques in catheter tip placement time or the measured optimal catheter length. The incidence of atrial premature contractions was higher with technique G than with technique P (13% vs 2%; P=0.003). Therefore, technique P is a practical alternative for correctly placing the catheter tip of a Port-A-Cath.

Depth of central venous catheter insertion in adults: an audit and assessment of a technique to improve tip position

A technique of subclavian vein catheterization is described, tailored to the individual patient, to reduce the risk of right atrial placement with central venous catheter (CVC) insertion. Using data gathered retrospectively for Quality Improvement purposes, CVC tip location was assessed. The standard technique used in our cardiac anaesthesia unit at that time was to insert all CVCs to a depth of 15 cm from the skin. We then compared CVC tip location using a new "tailored" technique. The tailored method involved measuring the distance from the skin at which venepuncture occurred and using this distance to determine depth of CVC insertion. Using the tailored technique significantly decreases the frequency with which CVC tips enter the right atrium (P < 0.001). An advantage of the tailored technique is that the distance between the most proximal and the distal ports of multi-lumen CVCs is taken into consideration, reducing the risk of extravasation via the proximal port.