MEDICAL MATTERS:Empirical evidence in favour of turning away, writes MUIRIS HOUSTON
PATIENTS OFTEN remark on how gently I administer injections (he says modestly). Indeed I was well taught by an experienced emergency department nurse, who told me of a simple technique to which I subsequently added a common twist.
The nurse’s advice was to give a decent “pinch” – or more correctly a “finger-flick” – against the area of the patient’s skin into which I was about to plunge a needle. This acted as a distraction but also meant the nervous system was busy transmitting the stimulus of the pinch when the needle insult followed. And I have found it helpful to say “look away now please” just before the injecting process begins.
But is there any scientific basis for my pre-injection manoeuvres? Well, a group of German investigators has just found that, in fact, your past experience with needle pricks, along with information you receive before an injection, shape your pain experience.
In research published in the medical journal Pain, Dr Marion Hofle and her colleagues subjected study participants to concurrent painful or non-painful electrical stimuli to their hands while watching video clips showing a needle pricking a hand, a soft Q-tip touching the hand or a hand on its own.
Participants reported that their pain was more intense and more unpleasant when they viewed a needle pricking a hand than when they saw a hand alone. In addition, observing needle pricks increased the unpleasantness of pain compared with viewing Q-tip touches. The investigators found enhanced activity of the autonomic nervous system that mirrored these observations.
In addition, when told in advance which video clip was more likely to be associated with a painful stimulation, participants rated their pain experience as higher – indicating how expectations about the painfulness of medical treatments influence the amount of pain actually produced. Commenting on her findings, Hofle says doctors should consider “providing information that reduces a patient’s expectation about the likely strength of pain associated with a forthcoming injection”.
“Because viewing a needle prick leads to enhanced pain perception as well as to enhanced autonomic nervous system activity, we’ve provided empirical evidence in favour of the common advice not to look at the needle prick when receiving an injection,” she concludes.
The other, belated, evidence for my injecting practice came from a chance meeting at the recent Tedmed conference with a paediatrician who has developed a device called “Buzzy”, which combines cold and vibration to block pain.
Buzzy is a palm-sized massager, with a slot for ice-cold wings. For children, the device looks like a friendly bee, while the adult version is plain black. Buzzy is placed on the skin “between the brain and the pain” to confuse the pain nerves with alternate sensations. Research carried out in an emergency department in which the device was used while taking blood has demonstrated significant pain relief, while trials of its effectiveness for injections such as vaccinations are under way.
Dr Amy Baxter showed how the Buzzy works. By switching on the vibration about 15-30 seconds before the painful procedure and placing the device just above the needle entry point, the subsequent sharp sensation is masked by the vibration and the optional cold pack “wings” which sit under Buzzy next to the skin.
And while the news in last week’s HEALTHplus about the development of microneedle patches for drug and vaccine delivery is welcome, Baxter feels the new technology may not work for everyone.
“We found that those who are more anxious about needles seem to actually feel pain more intensely,” adding some 22 per cent of adults fear needles sufficiently to avoid healthcare.
The Buzzy is currently going through the licensing process for approval here and in other European countries. (See buzzy4shots.com.)
In the meantime, I will continue to advise patients to look away, having finally found validation for that otherwise cringeworthy medical bon mot, “just a little prick with a needle, dear”.