Original Contribution
Efficacy of ShotBlocker in reducing pediatric pain associated with intramuscular injections

https://doi.org/10.1016/j.ajem.2008.04.011Get rights and content

Abstract

Objective

The aim of the study was to determine the efficacy of ShotBlocker (Bionix, Toledo, Ohio) in reducing pediatric pain with intramuscular (IM) injections.

Methods

A prospective randomized controlled trial was conducted in children aged 2 months to 17 years who required an IM injection. Children were randomized to the no-intervention group or the ShotBlocker group. Demographic data and the number of IM injections were recorded. Perceived pain scores were obtained from nurses and caregivers using a 6-point Likert-type scale. Baker Wong Faces scale was used in children 36 months or older. Difficulty using the device was also rated by nurses on a 6-point scale.

Results

One hundred sixty-five children were enrolled with 80 in the no-intervention arm and 85 in the ShotBlocker arm. The mean age of children was 45 months and 56% were male. Perceived pain scores by nurses were higher for the no-intervention group (2.6 vs 1.8, P < .001) as well as by caregivers (2.6 vs 2.1, P = .04). Children aged 36 months and older (n = 64) did not report a difference in pain scores (1.5 vs 1.3, P = .6); however, in a subgroup of children 72 months or older, pain scores trended higher in the no-intervention group (1.3 vs 0.5, P = .051). Nurse-perceived difficulty of ShotBlocker use was low 1.39 (±1.1).

Conclusions

Nurses and caregivers noted lower pain scores in children assigned to the ShotBlocker group. These differences were not as evident when children rated their own pain.

Introduction

Intramuscular (IM) injections are a common painful part of routine health care and pediatric emergency department (ED) visits. Current recommended immunization schedules require children to receive up to 20 separate injections before reaching 2 years of age, depending on the combination of vaccines used [1]. In 2001, the American Academy of Pediatrics and the American Pain Society jointly released a policy statement addressing pediatric pain. This statement acknowledged that children's pain is often inadequately controlled and provided recommendations for minimizing pediatric procedural pain. Proposed reasons for pediatric oligoanalgesia include a general misunderstanding of pediatric pain, time constraints in a busy ED or office, health care provider lack of knowledge of children's developmental stages and pain awareness, and concerns about using prophylactic or therapeutic pharmacologic treatments in children [2].

The ramifications of insufficient pain control in children extend beyond the immediate painful encounter. Pediatric and parental anxiety regarding painful procedures has been demonstrated to detract from other aspects of the health care visit. In 2007, an evidenced-based review of pain reduction during pediatric immunizations noted that children and parents have substantial concerns about the pain associated with injections. Children's anxiety about injections often detracted from other important aspects of the visit such as anticipatory guidance and health care instructions, and parental anxiety adversely affected compliance with their children's medical care [1].

Interventions would ideally be inexpensive, noninvasive, and rapidly applied to improve pediatric pain control. One device that is not yet approved by the Food and Drug Administration but is undergoing testing is the ShotBlocker (Bionix, Toledo, Ohio), a drug-free plastic device that is pressed against the skin during injection. It requires no advance preparation or wait time and has no known side effects. The ShotBlocker has a number of short blunt contact points on the underside that are placed directly on the skin before injection with a central hole for administering the injection (Fig. 1A and B). These points do not puncture the skin and provide the stimulus for the gate theory, a pain pathway postulated by Melzack and Wall [3], [4]. They theorized that both large-and small-diameter peripheral nerve fibers carry pain and pressure stimuli to the central nervous system where a gate mechanism modulates the pain signal [3], [4]. The proposed mechanism of action of the ShotBlocker is that the application of pressure to the skin excites the smaller-diameter, faster fibers. This stimulation closes the gates to the central nervous system, temporarily blocking the slower pain signals of the injection. In theory, this simple, noninvasive device should decrease the pain associated with IM injections. To our knowledge, this device has not yet been formally tested in a large sample of pediatric patients. We hypothesized that the use of the ShotBlocker as compared to standard of care (no intervention) would decrease pediatric pain as measured by validated pediatric pain scales.

Section snippets

Materials and methods

The objective of this prospective randomized controlled trial was to measure the efficacy of the ShotBlocker in a convenience sample of children receiving IM injections as part of their medical care. This study was approved by the Cooper University Hospital institutional review board, and informed written consent was required of all caregivers. Subject assent was additionally required of children aged 12 to 17 years.

Results

Over a 13-month period, 185 children were eligible and 165 children were enrolled, 64 of whom were old enough to provide pain scores. A flow diagram illustrating participant enrollment and group allocation is shown in Fig. 2. There were no differences in baseline characteristics between groups, including previous immunization history and caregiver-perceived pain with the most recent immunization. With this immunization, most children (92%) presented for a routine well child visit or

Discussion

In the United States, children receive as many as 5 immunizations at each well child visit and a total of 26 by their 6th year [7]. Given the large number of injections administered to children, pain and anxiety levels are high and have been found to detract from routine care [1]. In a study examining routine pediatric immunization practices, investigators determined that 58% of physicians did not provide children with any topical or oral pain relief [8]. Similar rates for the management of

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