Watch Needle, Watch TV: Audiovisual Distraction in Preschool Immunization

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1 PAIN MEDICINE Volume 3 Number Watch Needle, Watch TV: Audiovisual Distraction in Preschool Immunization Keri-Leigh Cassidy, MD, a,f Graham J. Reid, PhD, CPsych, b,g Patrick J. McGrath, PhD, b,c,e G. Allen Finley, MD, b,d,e Deborah J. Smith, MD, c Charlotte Morley, MD, c Ewa A. Szudek, MD, c and Bruce Morton, MD c,h Departments of a Medicine, b Psychology, c Pediatrics, d Anaesthesia, and e Pediatric Pain Service, IWK Health Centre, and Dalhousie University, Halifax, Nova Scotia, Canada; f The Hospital for Sick Children, Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada; g Departments of Psychology and Family Medicine, University of Western Ontario, London, Ontario, Canada; h recently deceased ABSTRACT Objective. To evaluate the effectiveness of audiovisual distraction compared with a blank TV screen in the reduction of pain associated with intramuscular immunization. Design. Subjects were randomly assigned to watch television (TV) (N 29) or a blank TV screen (control) (N 33) during immunization, and were videotaped. Immediately after the injection, the children rated their pain. Videotapes were coded for pain behaviors and for distraction. t tests determined between-group mean differences and chi-square tests compared proportions for clinically significant self-reported pain. Setting. Two urban pediatric practices in Halifax, Nova Scotia, Canada. Subjects. Five-year-old children (N 62), undergoing diphtheria, polio, tetanus, and pertussis immunization, and their parents. Interventions. An age-appropriate musical cartoon or a blank TV screen. Outcome Measures. Pain measurements were the children s self-reports on Faces Pain Scale, facial actions on Child Facial Coding System, and Children s Hospital of Eastern Ontario Pain Scale. Distraction was measured by mean time spent watching the TV screen. Parents rated their own and their child s anxiety on a visual analogue scale. Results. There were no significant group differences for any pain or distraction measures. The relative risk estimate for clinically significant pain among the distraction group was 0.64 (range: ). Higher levels of distraction (i.e., greater time looking at the TV screen) related to lower levels of pain on all three pain measures. Only correlations with objective pain measures were statistically significant. Conclusions. Watching cartoons did not distract children during needle injection nor reduce their pain. Looking at the TV screen was related to lower behavioral pain scores in the total sample. Key Words. Distraction; Audiovisual; Pain; Children; Immunization Reprint requests to: Dr. Keri-Leigh Cassidy, c/o Ms. Pat Follett, The Hospital for Sick Children, Department of Psychiatry, University of Toronto, 555 University Avenue, Toronto, Ontario, Canada M5G 1X8. Tel: (416) ; Fax: (416) ; kcassidy@istar.ca. Introduction Needles are reported by children to be painful [1 3] and anxiety provoking [4]. Hospitalized children cite needle procedures for blood tests and medications as the most common painful events [5] and the most difficult part of a hospital experience [6]. Fear of needles can lead to avoidance of appropriate American Academy of Pain Medicine /02/$15.00/

2 Distraction Analgesia in Children 109 medical care in childhood and adulthood [7]. The specific impact of routine immunization on children s negative needle experience is not known, and there is no consensus on the clinical significance of immunization needle pain for children. Many healthcare workers use distraction methods to help children cope with immunization pain. Distraction directs attention away from sensations of noxious stimulation. Theoretically, distraction reduces pain by competing for the attention needed to process physical, emotional, and evaluative components of pain perception [8]. There are intuitive and theoretical reasons to use distraction to reduce pain and some evidence to validate the use of distraction with children. Distraction with talking and stories [9,10], music [2,11], cartoons [12,13], imagery [12,14,15], kaleidoscope [16], breathing [12,17, 18], blowing [12,19,20], and hypnosis [17,21] have been used with children undergoing bone marrow aspirations and lumbar punctures [12,17,18], dental procedures [9], cold-pressor paradigm [15], immunizations [2,10,13,20,22], and venipuncture [11,16, 19]. The literature on coping with pain among children tends to support distraction [23], but results are mixed. The largely adult- and laboratory-based information on distraction is similarly controversial and limited [2,24 26]. Of the three pediatric studies that examined whether distraction reduced venipuncture pain, one found a medium effect size [16] and two found no effect at all [11,19]. Effect size, or Cohen s d, [27], is the mean difference divided by a standard deviation estimate. Thus, if treatment produced a mean difference equal to one standard deviation, Cohen s d would be 1.0. Vessey and colleagues [16] found a medium effect (Cohen s d 0.65) of kaleidoscope visual distraction in reducing pain in 100, 3- to 11- year olds undergoing venipuncture. Manne et al. [19] found no effect of a party blower in reducing pain on self-report in 23, 3- to 9-year-old children. Using the reliable Faces Pain Scale [28] and the Children s Hospital of Eastern Ontario Pain Scale (CHEOPS) [29], Arts et al. [11] found no effect of music distraction in reducing pain in 180, 4- to 16- year olds undergoing routine venipuncture. One neonatal immunization study on anxiety found that parental vocalization, play, and rocking reduced infant stress, measured by infant cortisol levels and by parents rating of infants comfort, but no direct pain measure was used [28]. Of the five studies that examined whether distraction reduced immunization needle pain in preschool children, two found a small effect size [2,13], and three found no effect [10,20,22]. Cohen et al. [13] found a small effect (d 0.24) of visual distraction in reducing self-reported pain in 92, 4 6 year old children receiving immunization. Fowler-Kerry and Lander [2] found a small effect (d 0.39) of music distraction in reducing self-reported pain in 200, 4.5- to 6.5-year-old children undergoing intramuscular immunization. Three studies found no analgesic effect for party blowers [22], blowing air [20], or nonprocedural talk [10] among 3- to 7-year-old children receiving immunization, even when a reliable pain measure (Oucher pain scale) was used [10]. Since distraction was not independently measured in any of these studies, one cannot conclude whether distraction had no analgesic effect or the interventions were inadequate. Several major methodological limitations underlie the conflicting literature on distraction interventions with children: 1) The lack of sensitive and reliable pain measures; 2) The absence of objective distraction measures; and 3) The failure to consider the clinical significance of the results. Two pain measures used in distraction interventions, LeBaron and Zeltzer s five-point faces scale [13,19,22] and the Baker-Wong scale [16], have been criticized for confounding mood with pain (e.g., 0 happy and 5 tearful). The 10-cm Visual Analogue Scale (VAS) [20] was devised for use with adults and is not a reliable measure for pain in children [31]. Fowler- Kerry s pain measure [2] involved self-report on a four-point VAS. Unlike most other pain scales for children representing intensity of pain by varying size or differing facial expressions, the scale used in this study depicted four blocks of identical size and shape to represent pain intensity, and was of unknown validity and reliability. None of the studies used an independent distraction measure. A distraction measure is needed to determine if the intervention had the intended effect and if a reduction in pain was related to the degree of distraction [2,13]. The two studies that found a distraction effect did not consider the clinical significance of a small effect size [2,13]. Effect size is a measure of the overall strength of an intervention on the group, while clinical significance refers to the impact of the intervention at the individual level. The present study used valid pain measures, an objective distraction measure, and observed appropriate controls to determine the effectiveness of audiovisual (AV) distraction in reducing pain among children undergoing a routine diphtheria, polio, tetanus, and pertussis (DPTP) immunization. The primary outcome was pain on the child self-report Faces Pain Scale (FPS), with secondary outcomes

3 110 Cassidy et al. measured using the Child Facial Coding System (CFCS) and the CHEOPS behavioral pain scale. The mean time children spent watching the needle versus watching the TV provided an objective measure of distraction. The purposes of this study were to address inadequacies in the distraction literature and determine: 1) Whether AV entertainment reduced the pain of 5-year-old children undergoing immunization; 2) The clinical significance of the pain reduction using AV entertainment; 3) Whether there were differential effects of distraction on self-report and objective, behavioral measures of pain; and 4) Whether AV entertainment produced distraction. Methods Design The study design was a clinical randomized controlled trial. Subjects were randomly assigned to either a distraction (N 29) or a control group (N 33) using a standard randomization table for each cluster of 10 subjects. Children watched an ageappropriate musical cartoon (AV distraction) or a blank television screen (control). The intervention was selected on the basis of combining music (audio) with the cartoon (visual), each of which has been shown to distract children in this age group [2,13,16]. The intervention was also chosen for pragmatic reasons, being quick and simple to implement in clinical practice and well suited to an objective distraction measure. Subjects Subjects were 62, 5-year-old children, undergoing standard DPTP immunization in two urban pediatric settings, and their parents. Inclusion criteria were: 1) 5 years old; 2) Due to receive the standard DPTP preschool immunization; 3) In good health; 4) Developmentally normal (i.e., the absence of developmental delays, in the expert opinion of the attending pediatrician), and 5) Subject s parent/guardian agreement to participate after initial recruitment contact. Exclusion criteria were: 1) Previously immunized with the preschool DPTP vaccine; 2) Previously hospitalized; or 3) The presence of any acute (e.g., influenza virus) or chronic (e.g., diabetes) medical condition. There were 274 potential subjects who were 5 years old from the two practices. One hundred children had already received, or would receive, their immunization elsewhere, and 104 families could not be contacted by phone. Five participants were excluded on a medical basis (i.e., two had diabetes, one had sclerosing cholangitis, one had developmental delay, and one had a bacterial infection). Of the 65 eligible participants, three parents withdrew their children since they felt participation was inconvenient, leaving a final sample of 62 children and their parents. Twenty-nine children [12 (41.4%) boys] were randomly assigned to the distraction intervention group and 33 children [16 (48.5%) boys] were assigned to the control group. Almost all were Caucasian (93.5%). Procedures Participants were recruited by phone by one of the authors (KLC) or by the clinic secretary. The parent s informed consent and the child s assent were obtained at the time of the appointment. The parent completed a demographic questionnaire about their child (e.g., age, gender of child) and provided a rating of their own and their child s anxiety related to the immunization. In the waiting room, the child was trained to use the self-report pain scale by the researcher. Once in the examining room, the child sat on the examining table and faced a cm TV screen at eye level approximately 2 m away from the examining table. A video recorder was placed above the television. To minimize the impact of the researcher and increase the potential ecological validity of the intervention, the researcher stood behind the AV equipment to operate the video camera. The researcher s interactions with the child involved a greeting and asking the child to watch the TV screen. After informed consent was obtained in the waiting room, and immediately prior to the child s injection in the procedure room, the researcher asked the parent to stand on the right side of the child seated on the examining table. The parent was asked to hold the child s right hand, and not to talk during the intervention. One of four possible clinicians (three pediatricians, one nurse) approached the child from the left side. The clinician greeted the child, and stated that a needle would be given prior to the needle insertion. All children were told to watch the TV screen and were not provided any information regarding whether or not the TV would be turned on. In the AV distraction group, the cartoon was turned on by the researcher after the clinician approached the child from the left side and immediately before the immunization (i.e., at the beginning of the preneedle phase). The section of cartoon chosen was started at a point in a musical number, deliberately selected to be immediately and optimally engaging. All children received the vaccine in the left deltoid muscle. The immunization procedure was stan-

4 Distraction Analgesia in Children 111 dardized to be 1 ml of DPTP toxoid vaccine administered via a 25-gauge, 1-inch needle inserted into the mid-deltoid area at a 90 degree angle to the skin for a maximum of 10 seconds. Immediately after the injection, children rated their pain. Measures Anxiety. In the waiting room prior to the procedure, parents rated their own and their child s anxiety related to the immunization on a 10-cm VAS ranging from 1 no anxiety to 10 worst anxiety imaginable. The VAS has been found to be a highly sensitive measure for mood and pain in adults, with a uniform distribution and good correlation with descriptive scales [32,33]. Parental anxiety was measured to control for its potential impact on other ratings. Children s Self-reported Pain. Children reported their pain on the FPS immediately after the injection [11]. The FPS consists of seven faces depicting neutral or no pain 1 to most extreme pain imaginable 7 expressions. The scale was derived from children s drawings and has strong agreement in rank ordering and ratio-scale properties [28]. A rating of three or more on the FPS has been found to represent clinically significant pain [34], that is, at this level of pain, both children and parents feel pain medication is warranted. Children were trained to use the FPS by rating their pain from previous experiences with some examples from the literature of a mosquito bite (low pain), falling in the snow (moderate pain), and falling on the sidewalk or closing a door on the fingers (high pain) [2]. Behavioral Measures. Two objective pain measures (CHEOPS, CFCS) and two measures of distraction ( Watch Needle, Watch TV ) were scored from the videotapes by blinded raters for each of three experimental phases: Preneedle, needle, and postneedle. The preneedle phase consisted of a maximum of 10 consecutive seconds before needle insertion while the clinician held and swabbed the child s arm. The needle phase involved a possible 10-second block when needle insertion and injection occurred. The postneedle phase included up to 10 consecutive seconds after the needle was removed from the arm and the clinician swabbed the site. Children s Hospital of Eastern Ontario Pain Scale. Pain behavior was scored from videotapes using the CHEOPS by a rater blind to the intervention condition. The CHEOPS is a time-sampling behavioral pain scale with excellent interrater reliability, good internal consistency and validity, and high correlations with observer VAS pain scores [29]. Behaviors (cry, verbal complaints, torso movements, touching, facial expression, and leg movements) are rated on a 0 (antithesis of pain) to 3 (severe pain) point scale. A modified CHEOPS was scored in two 5-second blocks for each experimental phase. Leg movements, since legs were not seen on camera, and facial expression, to prevent data overlap with facial action scored in greater detail, were excluded. Coders were trained to 90% agreement on sample tapes. Interrater reliability (percent exact agreement) calculated on 20% of the data was 95%. Child Facial Coding System. Thirteen facial actions in the CFCS (Table 1) were derived from Ekman and Friesen s Facial Action Coding System [35] and from Grunau and Craig s Neonatal Facial Coding System [36,37] on the basis that they had been shown to be sensitive and reliable measures of pain in adults and neonates. The CFCS has been shown to be a valid measurement for pain in children [38]. Facial actions were scored on a second-by-second basis from videotapes for each experimental phase. Coders were trained by the developers of the CFCS (CTC and KLC) on sample tapes to 0.80 reliability, calculated using the Ekman and Friesen Conservative Facial Actions Coding System reliability formula [36]. Interrater reliability calculated on 20% of the data was Discrepancies were resolved by reviewing and discussing disparate coding, and calculating reliabilities between the trainee and the trainer on reliability tapes. Interrater reliabilities were calculated at regular intervals in an effort to reduce rater drift. Distraction Measures. Two objective distraction scores, Watch TV (i.e., time spent watching the TV screen) and Watch Needle (i.e., time spent watching the needle), were coded from videotape as pres- Table 1 Area of the Face Eyes Nose Mouth Child facial action coding system Facial Action Brow lower a Squint a Eye squeeze a Blink b Flared nostril Nose wrinkler a Nasolabial furrow a Cheek raiser a Open lip Upper lip raiser a Lip corner puller a,b Vertical mouth stretch a Horizontal mouth stretch a a Coded for intensity, where 0 no action, 1 slight action, and 2 distinct to maximal action; other facial actions coded as present. b Facial actions excluded based on factor analyses of needle phase.

5 112 Cassidy et al. ent or absent on a second-by-second basis for each experimental phase. Children who watched neither the needle nor the TV in a given second received a score of 0 on both variables. Reliability was calculated using the Ekman and Friesen Conservative Facial Actions Coding System reliability formula [36]. Coders were trained to 0.80 reliability on sample tapes. Interrater reliability calculated on 20% of the data was Statistical Methods Most of the variables were positively skewed. Mann- Whitney U tests were used to determine betweengroup mean differences and chi-square tests were used to compare proportions for clinically significant self-reported pain ( 3 on the FPS) [34]. Spearman correlation coefficients were used to examine relations among pain measures, distraction, and anxiety scores. Kruskal-Wallis H tests were used to examine any differences among the four technicians on pain, distraction, or anxiety. Ethics The experimental protocol was conducted in accordance with the ethical standards of, and approved by, the Izaak Walton Killam Health Center Ethics Review Board. Results Preliminary Analysis Principal components factor analyses were conducted to determine the most parsimonious representation of the facial action data. Each of the 4 seconds of data from the needle phase were analyzed, first using a two-factor solution and then a one-factor solution. The two-factor solutions resulted in numerous facial actions with loadings on both factors. A single-factor solution was the simplest and, consistently across each of the 4 seconds, 11 of the 13 facial actions had loadings above 0.30 (see Table 1). A composite facial action score was computed by summing the ratings for these 11 facial actions for each second in the first 4 seconds of each experimental phase and then averaging across the 4 seconds for each phase (preneedle, needle, postneedle). CHEOPS scores were summed for the first 5-second time block of each experimental phase. Distraction was summed for each second and then averaged across the first 4-second blocks. Alpha was set at 0.01 for all analyses to control for Type I errors. Due to the variable length of the procedural phases and procedural difficulties (e.g., child looked away from the video camera), some subjects had missing facial action data. For subjects missing three or more facial actions per second, data for the second were set as missing. For subjects with one or two missing facial actions, missing values were replaced by the next second of nonmissing data. Forty-nine subjects [27 distraction (16 girls) and 22 controls (13 girls)] who had complete CFCS data for at least 3 of the first 4 seconds from each experimental phase were used in all subsequent analyses. Between-Group Analyses There were no significant group differences for any of the pain (Table 2) or distraction measures (Table 3) during the needle phase. There were also no group differences in the number of children with clinically significant self-reported pain (Table 4). The relative risk estimate for clinically significant pain given assignment to the distraction group was 0.64 ( ). There were no significant group differences during the preneedle phase on the CFCS (distraction, mean: SD; control, mean: SD; Mann-Whitney U 235.0, P 0.78). The control group had higher CHEOPS scores (mean: SD) than the distraction group (mean: SD; Mann-Whitney U 289.5, P 0.012). There were also no significant group differences during the postneedle phase on either the CFCS (distraction, mean: SD; control, mean: SD; Mann-Whitney U 138.0, P 0.07) or the CHEOPS (distraction, mean: SD; control, mean: SD; Mann- Whitney U 387.0, P 0.931). During the preneedle phase, subjects in the intervention group had higher Watch TV scores (mean: SD) than controls (mean: SD; Mann-Whitney U 197.0, P 0.000). Dur- Table 2 Means, standard deviations, and group differences on the FPS, CHEOPS, and CFCS for the needle phase Group Pain Measures Distraction mean SD N Control mean SD N Mann-Whitney U FPS a , P 0.11 CHEOPS , P 0.88 CFCS , P 0.17 FPS Faces Pain Scale; CHEOPS Children s Hospital of Eastern Ontario Pain Scale; CFCS Child Facial Coding System. a FPS scores were missing for three children. Scale ranges: FPS: 1 no pain, 7 most extreme pain imaginable; CHEOPS: 0 antithesis of pain, 3 severe pain; CFCS: 0 no action, 3 distinct to maximal action.

6 Distraction Analgesia in Children 113 Table 3 Means, standard deviations and group differences in the distraction measures by treatment group for the needle phase Group Distraction measures Distraction mean SD Control mean SD Mann-Whitney U Watch TV , P 0.08 Watch Needle , P 0.90 Watch TV mean time per second spent watching the TV screen; Watch Needle mean time per second spent watching the needle. N 28 for distraction group; N 27 for control. ing the postneedle phase, there were no significant group differences in Watch TV scores (distraction, mean: SD; control, mean: SD; Mann-Whitney U 278.5, P 0.053). There were no significant group differences in child anticipatory anxiety scores (distraction, mean: SD; control, mean: SD; Mann-Whitney U , P 0.09) or in parent anxiety scores (distraction, mean: SD; control, mean: SD; Mann-Whitney U 407.0, P 0.41). There were no sex differences in self-reported pain or CHEOPS pain scores during the preneedle, needle, or postneedle phases. There were also no sex differences on the CFCS during needle or postneedle phases. During the preneedle phase, boys exhibited less facial action (lower CFCS scores, mean: SD) than girls (mean: SD; Mann-Whitney U 114.0, P 0.004). There were no sex differences in distraction or anxiety. There were no significant differences on the pain, distraction, or anxiety measures between the technicians. Correlational Analyses To examine the validity of the two objective pain measures, Spearman correlation coefficients with child self-report were calculated for each of the three study phases. For the needle phase, self-reported pain was significantly correlated with both behavioral measures (CHEOPS, r 0.47, P 0.001; CFCS, r 0.49, P 0.001). For the postneedle phase, FPS and CHEOPS were not significantly correlated (r 0.33, P 0.017) but the FPS and CFCS were (r 0.60, P 0.001). For the preneedle phase, the FPS self-report did not significantly correlate with either behavioral measure (CHEOPS, r 0.11, P 0.45; CFCS, r 0.01, P 0.95). Correlations between the two objective measures (CHEOPS and CFCS) were significant for the needle phase (r 0.63, P 0.001) and the postneedle phase (r 0.48, P 0.001), but not for the preneedle phase (r 0.28, P 0.06). Correlations between the two distraction measures and the three pain measures were calculated for the needle phase only. Higher levels of distraction (i.e., greater time looking at the TV screen) were related to lower levels of pain on all three pain measures, but only correlations with the objective pain measures were statistically significant (Table 5). Greater time watching the needle was related to higher levels of pain on all three pain measures; again only correlations with the objective pain measures were statistically significant. The parent-rated child anxiety was significantly correlated with higher levels of child-reported pain, less time spent watching TV, and more time spent watching the needle (Table 6). Parent s own anxiety was positively, but not significantly, correlated with the parent-rated child anxiety (r 0.31, P 0.018). Parent s anxiety was not related to any of the pain or distraction measures. Discussion AV distraction did not reduce immunization pain in 5-year old children based on self-report and two objective pain measures. There were also no group Table 4 Number of children reporting clinically significant levels of pain by treatment group Level of Self-Reported Pain Group 3 on FPS 3 on FPS % N % N Control Distraction FPS Faces Pain Scale (7-point scale); 3 on FPS child rated pain as less than 3 on FPS, or clinically nonsignificant pain; 3 FPS child rated pain as 3 or more, or clinically significant pain. Pearson chi-square 1.02 (P 0.31) Relative risk estimate 0.64 ( ) Table 5 Correlations between distraction and three pain measures for the needle phase Pain Measures Distraction measures FPS CHEOPS CFCS Watch TV ** 0.43** Watch Needle ** 0.37* FPS Faces Pain Scale; CHEOPS Children s Hospital of Eastern Ontario Pain Scale; CFCS Child Facial Coding System; Watch TV mean time spent watching the TV screen; Watch Needle mean time spent watching the needle. For FPS correlations, N 52; for CHEOPS, N 54; for CFCS, N 47. *P 0.01 **P 0.001

7 114 Cassidy et al. Table 6 Correlations between anxiety, pain, and distraction Pain Measures Distraction Measures Anxiety FPS CHEOPS CFCS Watch TV Watch Needle Child 0.37** ** 0.37** Parent FPS Faces Pain Scale; CHEOPS Children s Hospital of Eastern Ontario Pain Scale; CFCS Child Facial Coding System; Watch TV mean time spent watching the TV screen; Watch Needle mean time spent watching the needle; Child (anxiety) parent s rating of child s anxiety on Visual Analogue Scale (VAS); Parent (anxiety) parent s rating of own anxiety on VAS. VAS scale range: 1 no anxiety, 10 worst anxiety imaginable. Sample size ranged from N 44 to 59. **P differences in distraction (i.e., time spent watching TV), which is the most likely reason that the cartoon intervention was not effective in reducing the children s pain. The objective distraction measure revealed that, although the AV intervention was ineffective, a distraction analgesic effect was present. Attention directed away from the needle was related to less pain on the behavioral measures in the total sample, while attention directed at the needle related to higher pain. Regardless of whether the TV was off or on, those children who looked at the TV demonstrated less behavioral pain. This is the first time a relation between an objective distraction measure and decreased pain has been reported. These findings provide some support for the distraction analgesia effect. The results of this study both support and refute previous findings. The distraction analgesic effects with music and TV interventions for immunization and venipuncture pain have been small [2,11,16]. The effect size found in this study (d 0.35) was similar to that found by Fowler-Kerry et al. [2] (d 0.39) who advocated clinical application of music distraction and claimed that a difference of less than 1/2 unit (0.44) on a four-point scale was clinically significant. However, the absence of reliable and valid pain measures precludes drawing any conclusions from the Fowler-Kerry study, and the clinical significance of a small effect size was not examined. In the present study, inclusion of a measure of clinically significant pain (rated as 3 on the FPS) revealed no significant group difference in the percentage of children in clinically significant pain. Overall, one fifth of the children in this study had clinically significant pain. This is a substantial proportion of children receiving immunization and suggests that better pain control is needed for routine immunizations. The relation between children s immunization pain and the development of persistent negative views of needles should be examined further. High within-group variance in pain on the FPS, as reflected by the standard deviations (see Table 2), demonstrated that there were large individual differences in pain perception, that the distraction intervention was not potent, and that individual variables might have influenced pain. Anxiety has previously been found to have an important influence on procedural pain both in adults [40] and in children [39,41,42]. In the present study, the use of an anxiety measure revealed that higher levels of parent-rated child anticipatory anxiety were related to higher levels of pain and lower levels of distraction. The parent s own level of anxiety related to their rating of the child s anxiety, but was unrelated to any of the pain or distraction measures. Similarly, Fradet et al. [3] found that parents ratings of their children s distress correlated with the children s self-reported pain measures for venipuncture. In the present study, children s anxiety was found to be an important correlate of distraction, as well as of pain. Regardless of group assignment, anxious children were more likely to attend to the needle and less likely to be distracted by the TV. The clinical usefulness of distraction was not resolved by this study. A critical issue in this area of research is the validity of pain measures. The FPS and CHEOPS have been previously validated and, in the present study, the CHEOPS and the CFCS behavioral pain measures were positively and significantly correlated, indicating that all three pain measures used had good validity. Thus, the lack of effect for AV distraction on children s immunization pain cannot be discounted based on problems with pain measurement. The sample size for this study was based on an expected effect size (d 0.50) that was in the midrange of other studies that have found a distraction analgesic effect with needle procedures. We expected that the combination of audio and visual distraction in a musical cartoon would be an effective method of distraction and that, with the use of valid and reliable pain measures, we would be able to detect this effect. The intervention did not produce the expected effect size. The practical significance of an effect of this magnitude is debatable. Nine children would have to be treated to have one less child in clinically significant pain (i.e., number needed to treat 9.01). With effects of this size, clinicians in a busy practice may perceive distraction interventions for needle pain to be too weak to justify the time and effort. The lack of group differences in distraction suggests the need to identify more engaging interventions. Time spent watching TV, regardless of inter-

8 Distraction Analgesia in Children 115 vention group, was related to less pain on both objective measures but not on self-report. A more engaging intervention might produce more potent analgesia and, in turn, be related to less self-reported pain. For example, the kaleidoscope visual intervention used by Vessey et al. [16] produced a moderate analgesic effect on behavioral measures and might represent a more potent distraction than music or television. Uniqueness or novelty has also been associated with higher levels of distraction [43]. Cartoon watching might not have been novel enough for children, or the familiarity of the cartoon might have reduced its ability to distract the children. A task used for a longer duration, beginning prior to the procedural phase, or one that required more active participation and greater cognitive processing, such as imagery, might also be more distracting [2]. The adult literature concurs that imagery exerts inhibitory effects on pain [24]. One pediatric study found that parent-guided relaxation and imagery exercises significantly reduced fear and self-reported pain scores of children undergoing routine lumbar punctures for cancer therapy [18]. However, distraction studies have been criticized for their use of complex or impractical interventions that are unlikely to be applied in a busy practice [41]. Another criticism is the absence of objective distraction measures [2,13]. Strengths of the present study are that it included a distraction measure and that it was designed to be quick and simple, requiring minimal instruction to carry out the protocol in the context of clinical practice. A challenge in future research will be to find interventions that are adequately potent as well as pragmatic. Future research should include measures of distraction, task duration and task involvement to clarify these issues. Aside from the need for a more potent or novel intervention, other methodological issues might have contributed to the lack of group differences in distraction. First, children were not provided any information regarding whether the cartoon would be turned on. Thus, children in both groups might have watched the blank TV screen because all children were instructed to watch the screen, and all children likely expected to see some type of TV program. Second, children in the control group were asked to look at a blank TV screen in order to compare no treatment with AV treatment. Asking the children to look at the TV screen that was not turned on might have involved an element of distraction that contributed to a non-neutral control stimulus. The use of a distraction measure allowed us to uncover that children in the control group were distracted by the blank TV, and underscored the importance of the inclusion of this measure. It is possible that children found the presence of a blank TV anxiety provoking. It is not known whether procedure-related anxiety differed between the two groups. Anticipatory anxiety was higher in the control group, but not significantly, and the children s anticipatory anxiety was rated by parents prior to the procedure, and thus, was unrelated to the intervention. Third, measuring the brief 30-second window allowed the most salient information about pain to be captured, and is the standard approach within the facial action literature. The addition of measures of anxiety or distress throughout the preand postprocedural periods [39] and coping styles might have yielded additional useful information regarding the roles of distress and coping in dealing with acute painful medical procedures. Two main coping styles among children have been studied: attenders or monitors, who tend to focus on the noxious stimulus, and distractors or blunters, who tend to focus away from the stimulus. A measure of coping style was not included in this study for several reasons. Self-report coping measures have been established for older children (7 16 years) [44] and adolescents [45] but not for healthy 5-year olds. An observational measure, the Child-Adult Medical Procedure Interaction Scale [46], and a self-report measure, the Waldron/Varni Pediatric Pain Coping Inventory [47], have been validated to measure coping in children between 5 and 12 years of age who are chronically medically ill. These pediatric coping scales have not been validated for use in a normal, healthy population undergoing acute medical procedures. Furthermore, virtually all self-report measures use 8 years as the lower age limit, and Varni et al. [47] do not report how many 5-year olds were in their sample. In addition, McGrath et al. [48] feel that children 5 years old or younger might not be capable of spontaneously coping with pain by distracting themselves or using other self-initiated cognitive strategies raising further questions about the validity of self-reported coping for young children. The conflicted literature on the relation between children s coping style and pain coping interventions is another reason we did not include a coping measure in the present study. Fanurik et al. [15] found, using the cold-pressor paradigm with 8 10 year old children, that matched interventions for children classified as distractors increased pain coping abilities in that group. Conversely, Smith et al. [49] found that pain management techniques that were mismatched with children s preferred coping

9 116 Cassidy et al. styles, were most effective in reducing subjective rating of procedural pain in pediatric cancer patients. Similarly, Christiano et al. [50] found that, during dental restoration, children s distress increased when interventions matched coping style. Coping behaviors vary within the same individual and over time. Temporally, some studies have found that spontaneous coping in children [51] and coping in adults [52] shifted across different stages of medical procedures. Blount et al. [51] found that during bone marrow aspirations, children used humor and distraction during the nonpainful stages and deep breathing during the painful stages. The effectiveness of these coping strategies could be related to distress prior to the procedure, as the injection had not yet been given. Further research is needed to identify important individual differences among children that are predictive of pain and distraction, such as their coping styles [15], prior experiences [49], and anxiety [3, 41,42]. Future studies on distraction should include objective and subjective measures of distraction, as well as of previous experience, anxiety, and coping style to better elucidate the complex relationships among these factors and their impact on pain, both within a procedure and over time. Research in normal children at various developmental stages undergoing routine clinical procedures is needed to elucidate how to best target children in the clinical setting, and to determine what combination of interventions effectively modulates their pain. Given the small effects of distraction analgesia, its role in clinical settings is likely best as an adjunct to other interventions such as a local anesthetic. Lidocaine-prilocaine emulsion (EMLA cream, AstraZeneca) has been well demonstrated to effectively reduce venipuncture pain in children [11] and has been found to be an effective anesthetic in immunization in adults and in infants [53 55]. One study compared distraction with EMLA analgesia in children [11], but no known research to date has examined their combined effect. Further research in this area is warranted. In summary, this study suggests that clinicians might be able to identify, through parent report, a subset of anxious children who are at high risk of having significant pain from immunization. The findings also suggest that anxious children might be less amenable to distraction, and further research is needed to determine what interventions should be used in the subgroup of children at risk for pain. Complex relationships emerge among coping style, anxiety, distraction, and pain. In this study, we found that more anxious children had more pain and were less distractible, suggesting that anxious children might be targeted by interventions to reduce anxiety, thus enhancing their distractibility in order to reduce pain. Preliminary evidence to support targeting high-risk groups in the clinical setting [56] found that children undergoing lumbar puncture, who were previously identified as being more pain sensitive and had received a stress-reducing intervention, had greater decreases in distress during the procedure. In the future, high risks groups might also be targeted with a combination of interventions [57], which might involve the flexible use of relaxation and distraction interventions, as well as topical anesthetics. Conclusions This study demonstrated that AV distraction did not reduce immunization pain in 5-year-old children. The use of an objective distraction measure revealed that, although the AV intervention was not effective, a distraction analgesic effect was present. Distracting attention away from the needle was related to less behavioral pain in the total sample. This is the first time a relationship between decreased pain and an objective distraction measure has been reported, and provides some support for the distraction analgesia effect. One fifth of the children in this study had clinically significant pain, a substantial proportion of children receiving immunization. Higher pain levels were related to parent-rated child anticipatory anxiety and lower levels of distraction. This finding suggests pediatricians might identify, through parent report, anxious children who might be at higher risk of having clinically significant immunization pain. Iatrogenic pain remains a dilemma in pediatrics. A painful immunization experience may have longterm effects on the doctor-patient relationship, and early negative medical experiences may affect children s future healthcare use. Distraction might offer a simple, quick, and inexpensive intervention of potential benefit to pediatric practice. Acknowledgments The following people are gratefully acknowledged for their significant contributions to this research: Barbara A. Follett and M. Elizabeth Mahaney, for coordinating and participating in the clinical aspects of the research; Christine T. Chambers for contributing significantly to the development of the Child Facial Coding System, for training CFCS coders, and for performing reliability ratings;

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