SULFUR-HEXAFLUORIDE AND PERFLUOROPROPANE DO NOT ESCAPE FROM A PLASTICSYRINGE CLOSED WITH A STOPCOCK

PURPOSE: To evaluate during various intervals of time the escape of lo ng-acting gases contained in a plastic syringe closed with a stopcock or a plastic cap. METHODS: A 60-ml plastic syringe was filled or parti ally filled with a long acting gas, either sulfur hexafluoride or perf luoropropane. The tip of the syringe was closed with either a stopcock or the syringe's plastic cap. After various intervals of time, the co ncentration of the long acting gas in the syringe was measured by gas chromatography. RESULTS: The concentration of both long acting gases w as higher than 98% at 24 hours after filling when the syringe was clos ed with a stopcock; however, it was less than 41% when the syringe was filled and capped tightly with its plastic cap. CONCLUSION: The propo rtion of long-acting gas es escaping in 24 hours from a filled syringe capped with a stopcock is clinically insignificant.