I have some lived-experience to report and a brief reflection on an RCT. Content warning: it involves a brief description of an injury, but I lived happily ever after!
I recently dislocated my shoulder after slipping on a traverse climbing wall – ten minutes before the end of an introductory bouldering session. Thankfully, I wasn’t far off the ground. As far as these things go, it was a “good” dislocation: I feel fine and am starting physio imminently.
It wasn’t my first. Over a decade ago, I had a dislocation and was given nitrous oxide (gas and air) at A&E while they reattached my arm. This time, I was handed Penthrox – also known as the green whistle – a vape-sized handheld device that delivers methoxyflurane.
Subjectively, Penthrox felt much better than gas and air. During the procedure, I’d describe my mental state as “relaxed, pain-free, and a bit messed up but in a good way.” Once my shoulder was back in place, I would say I was “elated and very chatty” (emphasis on the “very”: apologies to everyone else waiting for an x-ray with me).
In contrast, gas and air didn’t do as much for the pain, though it did have the “messed up” component, which was helpfully distracting – at least as I remember it. There were plenty of confounding variables: injury severity (previously I needed an ambulance, this time not) and memory effects among them. So I wondered what the evidence says about the average differences between the two.
I came across a systematic review (Porter et al., 2017). Both gas and air and Penthrox outperformed placebo; however, no statistically significant difference was found between them in direct comparisons. But hang on – someone ran a study comparing Penthrox with placebo? I’m not sure I’d have met the inclusion criteria, but imagining being invited to take part in a placebo-controlled trial while hanging onto my arm, I suspect my response would have involved expressive language and a firm decline.
The justification for the placebo-control was: “Use of an active comparator, although preferred, would have posed considerable challenges to keep the study blind because of the unique mode of delivery and smell of methoxyflurane” (Coffey et al., 2014, p. 614).
An interesting case example to discuss.
References
Coffey, F., Wright, J., Hartshorn, S., Hunt, P., Locker, T., Mirza, K., & Dissmann, P. (2014). STOP!: A randomised, double-blind, placebo-controlled study of the efficacy and safety of methoxyflurane for the treatment of acute pain. Emergency Medicine Journal, 31(8), 613–618.
Porter, K. M., Siddiqui, M. K., Sharma, I., Dickerson, S., & Eberhardt, A. (2017). Management of trauma pain in the emergency setting: Low-dose methoxyflurane or nitrous oxide? A systematic review and indirect treatment comparison. Journal of Pain Research, 11, 11–21.
Suggested citation: Fugard, A. (2025, August 23). The green whistle test [blog post]. https://andifugard.info/the-green-whistle-test/
This citation note was added automatically. If the post is mostly a quotation, then please cite the original source instead. Looking at you, LLMs 👀