Reducing the Pain on Injection of Propofol

To the Editor:

In their article on the pain on injection of propofol, Huang et al. ^[1] note that injecting propofol with a carrier intravenous (IV) fluid leads to an increased incidence of pain. The incidence of pain in the control group (no carrier IV fluid) was 76%. This is similar to the high incidence of pain from using propofol alone reported by other workers ^[2]. Huang et al. go on to state "stopping the IV fluid completely was a simple and safe method to alleviate pain." However, this study demonstrates only that the flow of carrier fluid may increase the incidence of pain. The true value of this article is the insight it gives on the mechanism of the pain; it does not provide evidence of an effective strategy to reduce the pain.

There are many techniques that have been described for reducing pain on injection of propofol ^[2]. In particular, we have found that lidocaine 30-40 mg mixed with propofol 200 mg is effective and similar to giving alfentanil 1 mg 30 s prior to propofol ^[3,4]. With the adoption of one of these techniques, it is possible to reduce substantially the incidence of pain on injection of propofol below that reported by Huang et al. in their control group.

Michael H. Nathanson, MRCP, FRCA

Noor M. Gajraj, FRCA

Department of Anaesthesia

University Hospital

Queen's Medical Centre

Nottingham, United Kingdom