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.

Isoflurane-induced hypotension in orthognathic surgery.

The effect of isoflurane-induced hypotension on reduction of blood loss, improvement of surgical field, and postoperative edema was investigated in 52 patients undergoing combined maxillary and mandibular osteotomies. Anesthesia was maintained with fentanyl, N2O, O2, and isoflurane. Deliberate hypotension was induced by increasing isoflurane inspired concentration. Blood loss in the hypotensive group (MAP 55-65 mm Hg) was significantly less than that in the control group (MAP 75-85 mm Hg); 454.0 +/- 211.3 mL versus 755.3 +/- 334.6 mL (P less than 0.001). Fewer patients had to be transfused in the hypotensive group, 12.0% versus 44.4% (P less than 0.02). The surgical field was significantly improved by the hypotensive technique, but operative time was not shortened. Subjective and objective measurements of postoperative edema failed to show any effect of deliberate hypotension. Our data suggest that isoflurane-induced hypotension effectively reduces blood loss and the number of transfusions in orthognathic surgery.

A microbiological study of the contamination of the syringes used in anaesthesia practice.

In many operating theatres, it is common practice to reuse disposable plastic syringes with the same needles for several injections to different patients during the same day. This practice could lead to bacterial contamination of these syringes, making them an infection hazard to patients. We did a microbiologic survey of 100 of the most frequently reused syringes in our operating rooms and a control group of 100 single-use syringes. Only three of the syringes were contaminated in each group. None of the patients exposed to the syringes having a positive culture showed any sign of sepsis. Our data suggest that reusing plastic syringes is not associated with an increase in the incidence of bacterial contamination. However, contamination of the syringes by patients' blood, with the risk of cross-infections, remains a possibility and further studies are needed to evaluate this potential hazard.