How Sharp is a “Sharp Scratch”? A Mixed Methods Study of Verbal Warnings Issued Before Venipuncture

Abstract

Health care providers frequently issue a verbal warning before venipuncture. Communications that induce negative expectations in patients can lead to the "nocebo" response, defined as experiencing greater pain. But is this also true for "sharp scratch"? The study was conducted across 4 U.K. hospitals. Two separate surveys of health care providers and patients explored the prevalence, phraseology, rationale, and reaction to verbal warnings before venipuncture. Blinded adult patients already attending an outpatient department during a 2-week period were randomized to hearing a "sharp scratch" or the verbal cue "ready?" immediately before venipuncture. They were also asked to rate their pain (the primary outcome). 77% of 117 health care providers surveyed issued a verbal warning before venipuncture; 73% used "sharp scratch". Of 62 patients surveyed, 56% agreed that "sharp scratch" accurately describes venipuncture, and 64% agreed that they prefer "sharp scratch" to no warning. With increasing age, a preference came for an alternative warning to "sharp scratch" (P = 0.039) and to be distracted by conversation (P = 0.002). Of 192 patients in the randomized study, there was no difference in pain between the "sharp scratch" and "ready" groups. The numeric rating scores were 0.74 SD 1.06 vs. 0.88 SD 1.18, respectively. (P = 0.493). Most health care providers use the verbal warning "sharp scratch" before venipuncture. Most patients find this acceptable and prefer it to no warning. An exception may be elderly patients, who may prefer to be distracted by conversation. "Sharp scratch" makes no difference to the pain experienced compared with a verbal cue.