Risk of cross-infection related to the multiple use of disposable syringes.

The rate of blood contamination of IV tubings used in anaesthesia practice was investigated. Only IV tubings started in the operating room were studied. First, 300 tubings of three different types were tested at the three distal injection sites. The contamination rate was 3.3 per cent at the injection site closest to the IV catheter and 0.3 per cent at the furthest. The presence of a check-valve did not affect the contamination rate. Second, 300 third injection sites fixed at a level equal to or above the IV catheter were tested. None of them was contaminated. Finally, in order to evaluate whether changing the needle alone could prevent the contamination of syringes, injections were made into a tubing where blood was flowing. Thirty-four per cent of the syringes tested positive for blood. We conclude that IV tubings have a significant contamination rate in usual practice. This rate decreases as the distance from the IV catheter increases. The use of the third site fixed at a level equal to or above the IV catheter carries a lower risk of contamination. Changing the needle alone is a useless procedure to prevent cross-contamination.