May 30, 2012

Needles Hurt More If You Watch

BerlinWith all 50 states, the District of Columbia, and Puerto Rico allowing pharmacists to administer some vaccines and 39 states allowing pharmacists to administer any vaccine, here’s a question you’re likely to hear often:

“Will it hurt?”

Now, a new study suggests a good way to answer: Tell customers receiving injected vaccines that the needle will hurt less if they look away.

The research was reported in a recent issue of the journal Pain. For the study, participants watched video clips showing a needle pricking a hand, a Q-tip touching the hand, or a hand alone while concurrently receiving painful or nonpainful electrical stimuli applied to their own hand. The clips, on a screen located above the participants' hand, gave them the sense that the hand on the screen belonged to them.

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 to viewing Q-tip touches. Measurement of pupil dilation responses, which show enhanced activity of the autonomic nervous system, confirmed the findings. The needle sticks were perceived as more painful because of past experience, the authors noted.

"Throughout our lives, we repeatedly experience that needles cause pain when pricking our skin, but situational expectations, like information given by the clinician prior to an injection, may also influence how viewing needle pricks affects pain," says lead author Marion Höfle, a doctoral student in the research Multisensory Integration group at the Charité - Universitätsmedizin Berlin and the University Medical Center Hamburg-Eppendorf.

What you say before giving a shot also can influence pain levels. When participants were told that either the needle or the Q-tip picture was more likely to be associated with painful electrical stimulation, their expectations lead to higher pain intensity.

"Clinicians may be advised to provide information that reduces a patient's expectation about the strength of forthcoming pain prior to an injection," Höfle notes, adding that the study provides “empirical evidence” that it is better not to look when receiving an injection.

U.S. Pharmacist Social Connect