INTRODUCTION

Pain is one of the oldest symptoms described by man. It is a complex phenomenon which affects individuals since the very beginning of life and during their development¹⁾⁽². It serves as a warning mechanism, helping detect harmful physical or chemical events³, being described by theInternational Association for the Study of Pain(IASP)⁴as “an unpleasant sensory and emotional experience, associated with actual or potential tissue damage. Each individual learns to use this term through earlier experiences”.

Literature also describes pain as a subjective experience, hard to be quantified due to its affective and sensory components³⁾⁽⁵. A great number of studies highlight pain management as challenging to professionals, mainly when it entails children and adolescents⁶. However, only in the 1980s, pediatric pain started to be particularly examined by researchers, who reported psychological and emotional outcomes when it was not properly managed⁵.

It is common for hospitalized children and adolescents to experience pain on a daily basis, due to procedures or pathology itself². A study held in hospital settings showed that pain was present in 86% of the assessed children⁷. In patients, who underwent Hematopoietic Stem Cell Transplantation (HSCT), pain can be aggravated by chemotherapy side effects and acute post-transplantation complications, among them, gastrointestinal complications, oral mucositis, venous-occlusive disease, and Graft Versus Host Disease (GVHD)⁸.

The number of HSCT has been gradually increasing in Brazil⁹, once it is considered a type of therapeutics with high potential of cure for oncological, hematological, immunological and genetic diseases. Treatment aims to regulate hematopoiesis by replacing individuals’ faulty cells with donor’s healthy hematopoietic cells¹⁰. Despite its benefits, such a population gets vulnerable to multiple comorbidities, which lead them to a painful, often debilitating state, such as nausea, vomit, GVHD, infections, gastrointestinal complications and mucositis⁸.

Studies carried out with pediatric population point out that pain self-reporting post-HSCT may vary between 43% and 69%, having oral mucositis as well as gastrointestinal complications as the main causes⁸. Pain management, in this context, is hard as it fundamentally depends on the resolution of its cause, and professionals’ endeavor by using different management strategies, aiming at the child or teenager’s well-being as a qualitative study showed, in which children and parents reported the need to improve pain management, once they considered that the nursing team had failed in their assessment and guidance on pharmacological therapy¹¹.

By considering pain one of the main symptoms of pediatric HSCT, as evidenced by literature, as well as the existence of several pharmacological and non-pharmacological strategies for pain management in children and adolescents, it was verified the need to reflect on the theme¹¹. Thus, the current study objectified to identify, in scientific productions, strategies of pain management for children and adolescents undergoing HSCT.

METHODOLOGY

It is an integrative literature review. This method comprises the process of elaboration and organization of a body of literature, which allows the inclusion of experimental and non-experimental studies to interpret a certain theme. Thus, it contributes to the development of a clinical and practical theory, informing new evidences in scientific research.

In the process of elaboration of this study, six steps were used: 1) theme identification and formulation of the guiding question; 2) definition of the sample inclusion and exclusion criteria; 3) profile of the pre-selected studies; 4) analysis of the findings; 5) result interpretations; and 6) synthesis of the results¹².

In the first step, the following guiding question was formulated: “What are the strategies used for pain management in children and adolescents who underwent HSCT?”.

For sample selection, inclusion criteria were defined as follows: articles whose addressed theme entails strategies of pain management for children or adolescents undergoing HSCT, indexed in national and international databases, with complete texts in English, Portuguese or Spanish. It should be pointed out that, facing the scarcity of findings; it was opted for not using temporal clipping.

Regarding the exclusion criteria, they consisted of review articles or the ones which did not involve research with human beings, studies exclusively carried out with adult population, theses, dissertations and abstracts.

Search was held between June and July, 2017, in electronic databases: MEDLINE, LILACS, ScIELO, BDENF, SCOPUS, Web of Science, and the platform of Brazilian journals from the Coordination for Higher Education Personnel Improvement (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES), using the boolean operators “AND” and “OR” in order to match MeSH descriptors: pain, pain management; pain pediatric; hematopoietic stem cell transplantation; bone marrow transplantation; and the acronyms BMT and HSCT. The amount of articles found per database, and in the platform of CAPES journals are organized inTable 1.

Table 1: Distribution of the total studies found in the electronic search, organized by databases and platform of CAPES journals. Curitiba-Paraná State, Brazil, 2017 

^*In the platform of CAPES journals, search was carried out by means of filters to make results more accurate.

Subsequently, a triage of the articles was held for the sample selection, with a more critical, deeper look at the texts. The selection was carried out according to the recommendations of the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA). (Figura 1).

Figure 1 - Flowchart for the study selection 

An instrument of data collection was elaborated by the researchers in order to characterize the selected articles by means of the Microsoft Office Excel® 2016, contemplating: authors, year of publication, journal and venue, in addition to major information about the studies, such as objectives, method, strength of evidence and results.

The authors elaborated another instrument for the analysis of the quantitative studies in order to facilitate the interpretation of the findings, comprising the following data: strategies used for pain management, instruments of pain assessment, pain location, assessment frequency and involved professionals.

The analysis of the studies, as well as their classification according to their strength of evidence, was held according to the recommendations of the Agency for Health care Research and Quality (AHRQ), which rates the strength of evidence in: level I, meta-analysis and systematic review; level II, single experimental studies, level III, quasi-experimental study; level IV, descriptive qualitative studies; level V, case studies; level VI, descriptive studies; and level VII, expert opinion⁹.

RESULTS

The selected studies for the synthesis are available on the SCOPUS, MEDLINE and Web of Science databases. From the seven studies, two are available in these three databases, three were located by means of CAPES platform of journals, and are available in the SCOPUS and Web of Science databases concomitantly.

Regarding the characteristics of the analyzed studies, all of them were carried out in the United States, and published exclusively in English for the past twenty years, between 1995 and 2015.

As for the type of study, six were identified as quantitative ones, being two descriptive, two randomized clinical trials, one crossover study, and one qualitative study. Their strength of evidence ranged between II and VI. It follows the Table with the detailed features of the studies used for knowledge synthesis (Table 2).

The reviewed studies were rated according to the tested strategies, in three types: “pharmacological strategies”^8)(13)(14, “non-pharmacological strategies”¹⁶⁾⁽¹⁷, “management strategy”¹⁵, and a qualitative study which verified children’s perception on the effectiveness of pharmacological and non-pharmacological pain strategies¹¹.

The subsequent Table describes the quantitative studies, considering the data for critical review, such as: description of the tools used for pain assessment, frequency of such evaluations, whether the pain site was mentioned, which strategy was used to manage the symptoms, and the professionals participating in this process (Table 3).

Table 3: Description of the quantitative studies regarding reference, pain assessment, strategy specification and implementation. Curitiba-Paraná State, Brazil, 2017. 

As for the qualitative study, it was observed that the authors did not use pain measurement tools, only considering children’s report of mild, moderate or severe pain. In relation to the therapeutic strategies for pain management, children reported that they requested painkillers when they felt pain, and asked their parents for other comfort devices: back or foot massage, warm compresses or recreational games to distract them. Regarding nurses’ strategies, all children reported that they administered medication to relieve their pain, and some mentioned the use of other strategies, such as warm compresses and cryotherapy¹⁸.

DISCUSSION

The reviewed studies pointed out that the effective control of pediatric post-HSCT pain is challenging for professionals in the area, demanding commitment, attention and will of those professional in order to assess, implement strategies for pain relief, to reassess the effectiveness of these strategies and adapt them to children and adolescents, according to their needs⁸.

The obtained outcomes indicated several strategies of pain management, although pharmacological therapies stood out in at least four studies^{8)(11)(13)(14}. The use of opioid painkillers by means of PCA and CCA pointed to the possibility of using this strategy for children and adolescents^8)(13)(14.

PCA is a therapeutic type for acute pain control⁸⁾⁽¹⁸. The American Society for Pain Management Nursing (ASPMN)^(18:177)supports and regulates such a therapeutic type, defined as: “approach that enables patients to self-administer small dosages of painkillers within a prescribed time, by pressing a dosage key of a previously programmed infusion pump”. That pain management strategy has become common due to its effectiveness by allowing individualized treatment, where patients themselves can control their pain⁸⁾⁽¹⁸.

Although it is an effective strategy, its recommendation for pediatric patients has been argued since its development, as some professionals believe that children and adolescents are not mature enough to distinguish medication risks and benefits^8)(13)(14. However, studies have contradicted such arguments. For example, a study held in the USA showed that 95% of the children between 4 and 12 years of age successfully mastered PCA, achieving effective pain control. Moreover, improper use of opioids was not reported, or parental adulteration, or even accidental overdose. Nevertheless, by carrying out a critical review of this study, it should be taken into account the reduced number of participants and lack of methodological accuracy, once it does not provide enough information on pain assessment¹⁴.

Therefore, we found other studies held in the HSCT context, which corroborate those data. A study tested the safety and effectiveness of a clinical PCA protocol in children and adolescents using morphine and hydromorphone, and achieved successful outcomes. However, the number of participants was also a limitation in this study¹³. Apart from those, another recent study identified that such therapeutics was used for 69% (n=51) of children and adolescents undergoing HSCT, being PCA for children older than 6 years of age and CCA for children younger than 6 years of age, evidencing that in both cases, the strategy was effective for reduction of pain complaints⁸.

It is important to point out that CCA or authorized agent controlled analgesia (AACA) is also allowed by the ASPMN for patients who are unable to independently use PCA, as long as the agent, that is, parents or caregivers, have a prescription and are oriented by the healthcare team on the probable risks of this practice¹⁸.

Regarding the use of pain management medication in the HSCT context, a qualitative study pointed that even using different strategies for pain management, children considered medication as the most effective therapeutics. In this study, they reported the use of several complementary strategies for pain management, carried out with their parents’ help, such as: listening to music, massages, playful activities and recreational games. In addition, they mentioned the use of heat application and cryotherapy held by nurses. However, we noticed that the authors did not properly explore such strategies, and did not report how they were performed, simply mentioning which ones¹¹.

Concerning musical intervention as a complementary therapy, literature points out its contribution in an effective way for pain reduction in children with cancer¹⁹⁾⁽²⁰. In addition, another study held with adults undergoing HSCT evidenced positive outcomes for this strategy to improve mood and pain (p=0,061)²¹. Thus, it can be inferred that it is possible to use that intervention in order to relieve pain in children and adolescents undergoing HSCT, once that method is non-invasive and inexpensive.

Aromatherapy is also considered a complementary strategy to relieve the symptoms. It is defined as the therapeutic use of essential oils from plants by using steam or pressure. The triggering mechanism in this method entails the respiratory system, which absorbs the volatile scent molecules through the nose. Subsequently, the molecules are changed into chemical signs which migrate to the olfatory bulb, amygdalas and lymbic system, interacting with the neuropsychological framework and, finally, generating some effect on the targeted tissues¹⁷.

Essential bergamot oil, used in aromatherapy, was described in the literature as natural anxyolitic and antiemetic for children, and it was applied to assess its effects on anxiety, nausea and pain as a secondary objective. However, it seemed to produce better effects on pain management than on the anxiety and nausea, raising the discussion about the need of further research to check the effect of aromatherapy with the essential bergamot oil for HSCT related-pain management for children and adolescents¹⁷. One of the study biases consisted of not offering participants a scent choice, considering that its smell might not have pleased the children, hindering final study outcomes.

As for extra-oral infra-red diode phototherapy, the results evidenced significant effects on oral pain relief in adults as well as in children and adolescents. Studies point to probable mechanisms responsible for such effects, such as the release of endogenous opioids, circulatory and angiogenic micro-effects, anti-inflammatory local action, and action on biochemical markers. However, such mechanisms have not been completely elucidated yet¹⁷.

It should be pointed out that the advantages of the extra-oral phototherapy are related to the reduction of patients’ manipulation and the time of the application, once it covers a wider affected area, besides being less invasive. However, there are disadvantages, such as the reduction in reaching over deeper targeted tissues¹⁷. In spite of evidencing the effectiveness of the extra-oral phototherapy, the study bias consisted of including adults, children and adolescents in the same trial, disregarding many differring factors between children’s and adults’ pain perception^17-21. Children have an individual response to pain which modifies along the time, according to their painful experiences throughout their lives. Therefore, children and adolescents’ response to treatment may also be different from adults’. It can be observed, for example, that pain response in children is more acute at the beginning, however, it ceases more easily than in adults²¹.

Regarding management strategies, a randomized study stood out, as it is a report entailing the elaboration of indicators to monitor the effectiveness of pain management using the goals imposed to hospital units so that pain is controlled within proper time to assure children and adolescents’ well-being¹⁵. However, the study setback lies in its lack of methodological accuracy, making its interpretation difficult. In addition, the study does not show how the results were obtained, even whether PCA or other therapies were used, contributing to achieve its objectives.

Brazilian researchers^(1:528)pointed out the main advantages, while taking into consideration the importance of using quality indicators to monitor pain management, such as: “to improve caring process and nursing notes, to provide information in order to help treatment choice, and contribute to enhance internal and public healthcare policies”. Thus, the quality indicators contribute to foster care for children and adolescents in pain¹. Results also pointed out that nurses are in the forefront regarding strategies for pain management, once all studies had their participation, either in the data assessment and collection, or carrying out the strategies for pain management, reassuring their importance for coping with pain in children and adolescents undergoing HSCT^{8)(11)(13)(14)(15)(16)(17}. Nevertheless, studies on the theme are scarce and need further exploration by professionals and researchers in the area.

CONCLUSION

Pain is the most frequent and debilitating symptom in children and adolescents undergoing HSCT. Therefore, it has been the target of studies for over 20 years. However, the management of this symptom has still been challenging for professionals in the area and demand successful innovative strategies. The strategies used for pain management were PCA and CCA with opioid painkillers (morphine and hydromorphone); aromatherapy with essential bergamot oil; extra-oral infra-red diode phototherapy; heat application; cryotherapy, and the elaboration of outcome indicators to monitor the effectiveness of pain management. In addition, complementary therapies were independently used by patients and their parents, such as: music, playful activities by means of games and massages. Among the mentioned strategies, the most effective were PCA, CCA and the outcome indicator, which enabled pain control at due time.

This study is relevant because it invests in the identification of strategies for pain management objectifying to contribute for the knowledge of professionals who work in HSCT services, pointing new ways for nursing decision making, reducing pain rates and favoring children and adolescents’ well-being.

Despite pharmacological, technological and complementary advances for the pain management in pediatric patients in the past two decades, the scarcity of scientific production on the theme has been evidenced in the same period. Thus, we highlight the need of further research, searching for innovative alternatives on the theme. Keeping in mind the identified knowledge gaps, we recommend the development of comparative studies between continuous opioid infusion and PCA or CCA, as well as deeper studies on complementary low-cost strategies, such as: massotherapy, music therapy, child psychotherapy, relaxation techniques, guided imagery therapy and aromatherapy.