Bacterial contamination of central venous catheters during insertion: a double blind randomised controlled trial

Static electricity within sterile packaging may result in bacterial contamination of central venous catheters (CVCs) prior to insertion. To prevent this, some surgeons inject saline into the pack before opening it. This trial was designed to determine the effect of this procedure. A double blind randomised controlled trial of 47 CVCs comparing injection of 2 ml of sterile saline into the pack prior to opening with no injection was performed. Five centimetre lengths cut from the tip of the catheter before and after subcutaneous tunnelling were sent for microbiological culture. Eight catheters (17%) showed evidence of bacterial contamination prior to insertion into the vein. Two (4.2%) were contaminated prior to tunnelling and seven (14.9%) afterwards. One catheter was contaminated before and after tunnelling. All but one of the contaminating bacteria were coagulase negative staphylococci. There was no significant difference in the contamination rate between catheters from packs that had been injected (5/25) and those that had not (3/22), P=0.56. Just under one-fifth of the catheters were contaminated with bacteria prior to insertion into the vein but this was not influenced by prior injection of saline into the pack. We conclude that there is no evidence to support the practice of injecting the catheter pack prior to opening.