On the proper sterile technique for handling of propofol.

To the Editor: I read with interest the report by Lorenz et al. regarding the proper handling of propofol.1 The authors compared two methods of dispensing this medication, either employing a technique of apparently high sterility or what they term a routine method. The result was that no difference in the contamination rate was found. However, a high rate of contamination was reported in both groups. I was surprised to read that the authors’ routine precautions included the re-use of syringes. The reason is that when a syringe has been filled with a medication, the plunger has been pulled out of the syringe’s barrel. The plunger may no longer be sterile since contact with the clinician’s fingers is likely. Then, when the drug is administered and the plunger is pushed into the barrel, the barrel too will no longer sterile. Consequently, upon refilling the syringe, the drug used may be contaminated. For this reason, syringes should never be refilled. This applies to all medications, not just propofol. In addition, the use of a stopcock when handling propofol is to be condemned. This is because the manipulation of the stopcock is likely to lead to the drug’s contamination by the clinician’s fingers, especially if some component attached to the stopcock, in this case the propofol syringe, is removed. Also, this study was not conducted in a blinded manner. Its result was negative, that is the null hypothesis, that the two techniques result in the same frequency of contamination was not disproved. This leads me to wonder if a larger study would reject the null hypothesis. Furthermore, the high frequency of contamination suggests that less than meticulous sterile technique was employed. In particular, the sterile technique that the authors term routine cannot be condoned.