Efficacy of microfiltration in decreasing propofol-induced pain

In a randomised, double-blinded, two-centre trial we evaluated the effect of a microbiological filter (Supor, Pall Life Sciences) on propofol injection pain. We studied 336 unpremedicated adult patients, who graded pain experienced during induction of anaesthesia with propofol on a 4-point verbal rating scale. Use of the microfilter reduced both the incidence and severity of propofol injection pain (p < 0.001). Incidence of severe pain in the filter group was 2.4% compared with 16.6% in the control group. Overall, 33.7% in the filter group experienced pain compared with 62.1% in the control group. A microbiological filter may provide a non-pharmacological alternative to a lidocaine/propofol mixture for reducing injection pain. It would also reduce the risk of any glass and bacterial contamination.