Distraction methods for pain relief of cancer children submitted to painful procedures : systematic review *

BACKGROUND AND OBJECTIVES: Pain is one of the most persistent cancer symptoms. Non-pharmacological therapies are potential sources for cancer children care and should be considered alternatives for handling cancer signs and symptoms. This study aimed at identifying effective distraction interventions for pain relief and control of cancer children submitted to invasive procedures. CONTENTS: This is a systematic review carried out in electronic databases LILACS, CINAHL, CENTRAL Cochrane Library and Pubmed, using the combination of controlled and uncontrolled keywords: child, pain, cancer and distraction. Ten studies were identified addressing distraction as intervention for venous, muscle and subcutaneous punctures, and procedures related to bone marrow aspiration and lumbar puncture. CONCLUSION: Among identified interventions, there are virtual reality, practices such as blowing soap bubbles, use of warm pads, party blower, electronic toys, among other self-selected interventions (music, games, books). Most interventions are easy to implement considering their low cost and are useful for health professionals looking for enhancing pediatric patients’ assistance with regard to pain management.


INTRODUCTION
Pain is one primary cancer symptom 1 , being experienced by all cancer children, with more than 70% of them having severe pain.So, there is the need to recognize this pain, even if subjectively understood, thus avoiding its inadequate treatment 2 .Common during diagnosis and management, pain may result from painful procedures, disease progression or nerve compression, among other factors 3 .It is important to note REVIEW ARTICLE DOI 10.5935/1806-0013.20150028that invasive procedures, common in different moments of the therapy imposed to cancer patients, induce the most distressing and difficult pain experiences for children and their parents, justifying further focus on handling pain related to such procedures 4 .Currently, adequate pain management is becoming increasingly relevant, since it is considered indicator both of quality of life (QL) and of the assistance itself 5 , being that such management should take into consideration physical, psychosocial and spiritual aspects of patients and their families 6 .So, one should understand the need for psychological support and the use of non-pharmacological methods, as well as teaching strategies aiming at handling pain, thus decreasing behavioral impacts generated during invasive procedures 7 .Non-pharmacological pain control therapies are potential sources for cancer children assistance and should be seen as alternatives to handle cancer signs and symptoms.In addition, it is critical to prioritize the investigation of their most different application manners and of their results to manage other signs and symptoms different from pain, such as nausea, vomiting and anxiety 8 .Knowledge coming from available evidences is an important tool for the identification of different types of non-pharmacological therapies to prevent or decrease invasive procedure-related pain 4 .This study aimed at identifying in the scientific literature effective distraction interventions for pain relief and control in cancer children submitted to invasive procedures, summarizing identified results, so that health professionals may use such information for the benefit of better assistance to pediatric patients in terms of pain management.We hope that the summary of existing knowledge on this subject may contribute to enhance the skills needed by health professionals when dealing with such patients.

CONTENTS
This is a systematic literature review, aiming at gathering all scientific evidences meeting pre-established eligibility criteria, to answer a specific research question.So, essential features of this review are: clear objective with pre-established selection criteria; explicit methodological reproducibility; systematic search to identify all studies which could meet eligibility criteria; evaluation of primary studies results, as well as a summary of their characteristics and results 9 .The guiding question of the research -"Which effective distraction interventions are used for pain relief and control in cancer children submitted to invasive procedures?" -was developed using the PICO strategy from the acronym: Patient, Intervention, Comparison and Outcomes.PICO strategy has shown to be efficient for effective evidences recovery, because it focuses on the objective of the research and prevents unnecessary searches 10 .Search went on until June 2014 in the following databases: LILACS, CINAHL, Cochrane Central Register of Con-trolled Trials (CENTRAL) and Pubmed.The following descriptors were used for the search: child, pain, cancer and distraction.Boolean operator "AND" was used for crosschecking among descriptors, establishing a single crosscheck as search strategy, namely: child AND pain AND cancer AND distraction.Inclusion criteria were clinical trials in Portuguese, English and Spanish addressing distraction interventions for pain relief and control in cancer children submitted to invasive procedures.Publication period limits were not adopted.We have identified 79 articles of which titles and abstracts were read, which allowed a priori selection of 15 studies.Since not all studies had in the abstract their methodological design or did not precisely indicate participants' age and could be or not studies involving cancer children, type of outcome and intervention being used, it was necessary to initially examine in full all pre-selected studies.So, from identified studies, five have not met inclusion criteria, being left 10 articles as observed in figure 1.It is important to note that repeated studies in one or more databases were considered only once.Articles data extraction and evaluation were independently made in pairs and divergences were discussed to reach a consensus.Selected articles were reviewed by means of their full reading and filling of data collection tool developed by the authors.Then, articles were classified according to essay methodological quality, considering Jadad Scale 11 (Table 1).Tem articles were identified which addressed distraction as intervention to remove children's focus from the invasive procedure to which they were being submitted.With regard to language, all articles were published in English.Publication years varied between 1988 and 2009 and age groups of studied sample has varied from 2 years to 19 years of age (Table 1).All selected articles used some way of non-pharmacological intervention based on distraction, such as behavioral cognitive intervention for venous, muscle and subcutaneous punctures, and procedures related to bone marrow aspiration and lumbar puncture (Table 1).
According to the articles, interventions were in general use-ful for pain relief or have shown decreased levels of anxiety, distress, affliction or fear present during invasive procedures (Table 2).
To evaluate the methodological quality of selected studies, Jadad Scale was applied, which evaluates criteria related to randomization, blinding and reasons for losing or excluding subjects from the study.According to these criteria, no study was considered of high-quality, as seen in table 1, which contains scores followed by justification.No evaluated study was characterized as double-blind, which has implied lower scores.

DISCUSSION
Non-pharmacological interventions used in selected studies differ among them with regard to the type of strategy.It is predominant the use of behavioral interventions using distraction as resource to control and manage pain in cancer children submitted to invasive procedures, as well as for the evaluation of behavioral factors, such as distress, affliction, fear and anxiety.Among distraction techniques found in the literature there is the use of electronic toys, relaxation, imagination, soap bubbles, warm pillow, self-selected distractions, party blower and virtual reality, being the two latter methods the most commonly used among selected articles.With regard to virtual reality, studies have pointed that such intervention may be effective for children submitted to painful and distressing procedures 14,15 .It is important to consider in which procedures such intervention may be used and un- According to parents' reports, children had less fear with submitted to proposed intervention as compared to standard treatment (p<0.001).Children had less fear (p<0.05) and distress (p<0.05) when submitted to standard treatment associated to the activity of blowing soap bubbles as compared to standard treatment alone (n=14), and less fear when submitted to standard treatment associated to warm pillow as compared to standard treatment alone (p<0.05).
Pain and fear reported by children were significantly correlated (p=0.01) in treatment groups, but not significantly different among groups.Intervention group participants have shown significantly less fear (p<0.001) and distress (p=0.03), as evaluated by the nurse, and less fear (p=0.07), as evaluated by parents.All intervention group parents have stated that puncture was better tolerated due to distraction.
Wolitzky, Fivush, Zimand, et al. 14 Children of both groups were not different in levels of anxiety and distress, or heart rate values before the procedure.During the procedure, groups were different in pain and heart rate measures, indicating that children under virtual reality have not suffered so much pain and anxiety and tend to be slightly less afflicted as compared to controls.
Gershon, Zimand, Pickering, et al. 15 Children of the distraction group with virtual reality had significantly lower heart rates as compared to control group children (p<0.05).Non-verbal distress indices indicated that control group individuals had more muscle tension as compared to those in the distraction group with virtual reality.Even more tension was identified on the leg both in the group with virtual reality and the group without virtual reality (p<0.05).
Dahlquist, Pendley, Landthrip, et al. 16 Children receiving distraction intervention had decreased distress behavior and lower levels of anxiety as compared to control group children, according to parents and nurses evaluation.Results suggest that adequately developed activity -varied, multi-sensory distraction, requiring active cognitive processing and active motor responses might be a feasible and low-cost alternative for preschoolers.

Broome, Rehwaldt & Fogg 17
There has been pain improvement during the period of five months, but distress behavior has not changed.At baseline visit, temperament, decreased activities, less persistence and distraction parameters were related to higher pain intensity reports, but not to distress behavior.However, after five months, only good mood parameter was related to better pain reports.Time spent by parents and children performing techniques, comfort of their performance and their efficacy were also correlated to good mood.
Manne, Bakeman, Jacobsen, et al. 18 Distraction technique was associated with less crying.Health professional encouragement and early procedure intervention have not indicated improvement on intervention effectiveness.Older children and those less distressed during initial procedure stage were less prone to reject the intervention.
Manne, Redd, Jacobsen, et al. 19 Results indicate that distress classifications observed by children, children's affliction according to parents' evaluation and self-evaluation of parents distress were decreased after behavioral intervention and were maintained along three intervention attempts.Physical contention to manage children's behavior was also decreased.Pain reported by children, and nursing evaluation of distress were not affected.
There were no differences between groups in fear or pain self-report.Children receiving information had higher heart rates as compared to those using distraction, regardless of coping style.The level of previous experience with invasive procedures may be an important factor for the preferred coping style when managing these patients' pain.

Kuttner, Bowman & Teasdale 21
In the first intervention session, observational evaluations of distress have shown reductions for the younger group under hypnotic treatment, while the group of older children had reductions in both treatment conditions for pain and anxiety.In the second intervention session, all groups had reductions and control group was seemingly contaminated.The hypnotic method with its internal focus had an everything-or-nothing effect, and distraction has required coping skills to be learned throughout one or more sessions.
der which conditions, since problems have been raised about low painful stimulation related to evaluated invasive procedure, that is, totally implanted venous catheter puncture, and the use of topic local anesthetics before the procedure 15 .One should also consider that some studies have reported that topic local anesthetics would be used at puncture site, which could interfere with results 12,13,15 .
Still about virtual reality, it is inferred from the literature the need for further studies about the application of this technology taking into consideration its cost-effectiveness ratio 15 .Further studies should compare virtual reality efficacy to other distraction methods 14 , considering the high cost of some equipment used for virtual reality as compared to other distraction or amusement techniques, such as soap bubbles our warm pillow, which are simple, low-cost interventions not requiring professionals workload increase, being this often considered a barrier for the adoption of unconventional treatment means 12 .Plural analysis of children's behavior face to invasive procedures, including painful stimulation, is performed by means of different evaluation scales.Such scales are applied before, during and after the use of non-pharmacological interventions.Importance should be given to visual analog scale (VAS) and physiological evaluation taking into consideration parameters such as heart rate (Table 1).Physiological evaluation measures are valued in articles as method of analysis since they have brought significant results to studies 14,15,20 , being even considered tools to be included in the evaluation of future studies of those who have not used them yet 19 .
Involving the family during care is critical.Studies have shown that parents are able to play an active role in supporting and training their children during the procedure 13 , fact that is confirmed by other studies which have also counted on parents' role during intervention and/or during evaluation 12,[14][15][16][17][18][19]21 .
The study working with party blower 18,19 , has also effectively incorporated parents in the intervention process, even evaluating their distress during procedure 19 .Parents-children relationship favors coping with and accepting the distraction intervention, during knowingly painful procedures.Manne et al. 18 suggest that the link between parents and children is extremely relevant for the effectiveness of the intervention when it depends on the training offered by parents to children.It was observed among selected studies that different distraction forms may be considered effective strategies for pain relief and control, in addition to decreasing distress, affliction, fear and anxiety; however the literature shows the need for expansion and analysis with regard to study samples.A large part of the studies state that sample was small 12,[18][19][20] indicating in their analyses the need for experiments with larger samples [13][14][15]18,20 . The wde variety of age groups (younger age=2 years and older age=19 years) causes major divergences, since it simultaneously encompasses different development stages and cognitive capacities, being even important to consider the use and evaluation of adequate devices for younger children 14,15 .On the other hand, Manne et al. 18 state that, according to their study data, older children tend to cooperate and present more positive results to distraction interventions as compared to younger children, for not rejecting distraction that much.It should be noted that studies have indicated as fragility the fact that they have not followed criteria with regard to evaluators blinding 14,15,19 .Aiming at preventing or decreasing possible biases of analyses and interpretation of results, we suggest the development of further studies with blind evaluators 14 .

CONCLUSION
The study allowed for the identification of evidences available in the scientific literature with regard to pain relief and control in cancer children using distraction practices.Among them there are virtual reality, practices such as blowing soap bubbles, use of warm pillow, party blower, electronic toys, among other self-selected interventions (music, games, books).Most interventions are easy to implement, considering their low cost, and are useful for health professionals looking at enhancing pediatric patients' assistance with regard to pain management.
Major study limitations were: decreased number of participants both in experimental and control groups, which does not allow for more robust conclusions.Distraction techniques were varied and were not deeply described, considering the broad guiding question, which makes difficult to elect the most effective distraction intervention and for which invasive procedure.In addition, studies should have worked with more specific age groups, since development competences of each child are quite different and interaction and response to stress are age-dependent.

Figure 1 .
Figure 1.Selection criteria for studies.Brasília-DF, Brazil, 2014 and anxiety S e l f -r e p o r t scale developed and validated for the study To compare the effectiveness of hypnosis, "imaginative involvement", behavioral distraction and standard medical practice to decrease pain, distress and anxiety in leukemia children during bone marrow aspiration.CAS = color analog scale; TI-CVC = totally implanted central venous catheter; VAS = visual analog scale; OSBD = Observation Scale of Behavioral Distress; CHEOPS = Children's Hospital of Eastern Ontario Pain Scale; PBRS-R = Procedure Behavior Rating Scale Revised.

Table 1 .
Distribution of articles according to year, internal validity according to JADAD scale, sample age group, invasive procedure, applied intervention, evaluation scales and objectives.Brasília-DF, Brazil, 2014 Continue...

Table 1 .
Distribution of articles according to year, internal validity according to JADAD scale, sample age group, invasive procedure, applied intervention, evaluation scales and objectives.Brasília-DF, Brazil, 2014

Table 2 .
Distribution of articles according to results and conclusions.Brasília-DF, Brazil, 2014