Non‐pharmacological management of infant and young child procedural pain

Abstract

Background

Despite evidence of the long‐term implications of unrelieved pain during infancy, it is evident that infant pain is still under‐managed and unmanaged. Inadequately managed pain in infancy, a period of exponential development, can have implications across the lifespan. Therefore, a comprehensive and systematic review of pain management strategies is integral to appropriate infant pain management. This is an update of a previously published review update in the Cochrane Database of Systematic Reviews (2015, Issue 12) of the same title.

Objectives

To assess the efficacy and adverse events of non‐pharmacological interventions for infant and child (aged up to three years) acute pain, excluding kangaroo care, sucrose, breastfeeding/breast milk, and music.

Search methods

For this update, we searched CENTRAL, MEDLINE‐Ovid platform, EMBASE‐OVID platform, PsycINFO‐OVID platform, CINAHL‐EBSCO platform and trial registration websites (ClinicalTrials.gov; International Clinical Trials Registry Platform) (March 2015 to October 2020). An update search was completed in July 2022, but studies identified at this point were added to 'Awaiting classification' for a future update. 

We also searched reference lists and contacted researchers via electronic list‐serves. 

We incorporated 76 new studies into the review. 

Selection criteria

Participants included infants from birth to three years in randomised controlled trials (RCTs) or cross‐over RCTs that had a no‐treatment control comparison. Studies were eligible for inclusion in the analysis if they compared a non‐pharmacological pain management strategy to a no‐treatment control group (15 different strategies). In addition, we also analysed studies when the unique effect of adding a non‐pharmacological pain management strategy onto another pain management strategy could be assessed (i.e. additive effects on a sweet solution, non‐nutritive sucking, or swaddling) (three strategies). The eligible control groups for these additive studies were sweet solution only, non‐nutritive sucking only, or swaddling only, respectively. Finally, we qualitatively described six interventions that met the eligibility criteria for inclusion in the review, but not in the analysis. 

Data collection and analysis

The outcomes assessed in the review were pain response (reactivity and regulation) and adverse events. The level of certainty in the evidence and risk of bias were based on the Cochrane risk of bias tool and the GRADE approach. We analysed the standardised mean difference (SMD) using the generic inverse variance method to determine effect sizes. 

Main results

We included total of 138 studies (11,058 participants), which includes an additional 76 new studies for this update. Of these 138 studies, we analysed 115 (9048 participants) and described 23 (2010 participants) qualitatively. We described qualitatively studies that could not be meta‐analysed due to being the only studies in their category or statistical reporting issues. We report the results of the 138 included studies here. An SMD effect size of 0.2 represents a small effect, 0.5 a moderate effect, and 0.8 a large effect. The thresholds for the I2 interpretation were established as follows: not important (0% to 40%); moderate heterogeneity (30% to 60%); substantial heterogeneity (50% to 90%); considerable heterogeneity (75% to 100%). The most commonly studied acute procedures were heel sticks (63 studies) and needlestick procedures for the purposes of vaccines/vitamins (35 studies). We judged most studies to have high risk of bias (103 out of 138), with the most common methodological concerns relating to blinding of personnel and outcome assessors. Pain responses were examined during two separate pain phases: pain reactivity (within the first 30 seconds after the acutely painful stimulus) and immediate pain regulation (after the first 30 seconds following the acutely painful stimulus). We report below the strategies with the strongest evidence base for each age group.

In preterm born neonates, non‐nutritive sucking may reduce pain reactivity (SMD ‐0.57, 95% confidence interval (CI) ‐1.03 to ‐0.11, moderate effect; I2 = 93%, considerable heterogeneity) and improve immediate pain regulation (SMD ‐0.61, 95% CI ‐0.95 to ‐0.27, moderate effect; I2 = 81%, considerable heterogeneity), based on very low‐certainty evidence. Facilitated tucking may also reduce pain reactivity (SMD ‐1.01, 95% CI ‐1.44 to ‐0.58, large effect; I2 = 93%, considerable heterogeneity) and improve immediate pain regulation (SMD ‐0.59, 95% CI ‐0.92 to ‐0.26, moderate effect; I2 = 87%, considerable heterogeneity); however, this is also based on very low‐certainty evidence. While swaddling likely does not reduce pain reactivity in preterm neonates (SMD ‐0.60, 95% CI ‐1.23 to 0.04, no effect; I2 = 91%, considerable heterogeneity), it has been shown to possibly improve immediate pain regulation (SMD ‐1.21, 95% CI ‐2.05 to ‐0.38, large effect; I2 = 89%, considerable heterogeneity), based on very low‐certainty evidence.

In full‐term born neonates, non‐nutritive sucking may reduce pain reactivity (SMD ‐1.13, 95% CI ‐1.57 to ‐0.68, large effect; I2 = 82%, considerable heterogeneity) and improve immediate pain regulation (SMD ‐1.49, 95% CI ‐2.20 to ‐0.78, large effect; I2 = 92%, considerable heterogeneity), based on very low‐certainty evidence. 

In full‐term born older infants, structured parent involvement was the intervention most studied. Results showed that this intervention has little to no effect in reducing pain reactivity (SMD ‐0.18, 95% CI ‐0.40 to 0.03, no effect; I2 = 46%, moderate heterogeneity) or improving immediate pain regulation (SMD ‐0.09, 95% CI ‐0.40 to 0.21, no effect; I2 = 74%, substantial heterogeneity), based on low‐ to moderate‐certainty evidence.

Of these five interventions most studied, only two studies observed adverse events, specifically vomiting (one preterm neonate) and desaturation (one full‐term neonate hospitalised in the NICU) following the non‐nutritive sucking intervention. The presence of considerable heterogeneity limited our confidence in the findings for certain analyses, as did the preponderance of evidence of very low to low certainty based on GRADE judgements.

Authors' conclusions

Overall, non‐nutritive sucking, facilitated tucking, and swaddling may reduce pain behaviours in preterm born neonates. Non‐nutritive sucking may also reduce pain behaviours in full‐term neonates. No interventions based on a substantial body of evidence showed promise in reducing pain behaviours in older infants. Most analyses were based on very low‐ or low‐certainty grades of evidence and none were based on high‐certainty evidence. Therefore, the lack of confidence in the evidence would require further research before we could draw a definitive conclusion.

Author(s)

Rebecca R Pillai Riddell, Oana Bucsea, Ilana Shiff, Cheryl Chow, Hannah G Gennis, Shaylea Badovinac, Miranda DiLorenzo-Klas, Nicole M Racine, Sara Ahola Kohut, Diana Lisi, Kara Turcotte, Bonnie Stevens, Lindsay S Uman

Abstract

Plain language summary

How can caregivers manage pain in infants and young children undergoing painful procedures?

Key messages

Non‐nutritive sucking (an object, such as pacifier, being placed in an infant's mouth to stimulate sucking behaviours), facilitated tucking (containing the infant using a care‐giver's hands on both head and lower limbs to maintain a 'folded‐in' position), and swaddling (wrapping the infant tightly in a blanket to prevent excessive limb movement) are among the most promising strategies that may reduce pain behaviours in preterm newborns. Non‐nutritive sucking may reduce pain behaviours in full‐term newborns. None of the strategies analysed reduced pain behaviours in older infants with sufficient evidence. Structured parent involvement (parents instructed on using strategies, such as shushing, rocking, tickling, or distraction, without being given any materials to aid them) did have a more substantial evidence base but did not have an effect on reducing pain behaviours.

Introduction of review topic

Infants and young children get exposed to several acute (lasting a short time) painful medical procedures in the first three years of life. Receiving these painful procedures without adequate pain management strategies can have negative effects on their development.

What did we want to find out?

We studied several pain management strategies (excluding kangaroo care, sucrose, breastfeeding/breast milk, and music due to existing reviews on these strategies) after acute medical procedures in preterm born newborns, full‐term born newborns, and full‐term born older infants up to the age of three, to understand how effective these strategies are at reducing pain.

What did we do?

We assessed 24 different strategies for reducing young children's pain after medical procedures using care‐giving strategies that do not require medication, such as using a pacifier, swaddling a child, and massaging a child. We compared the pain‐reducing effects of these strategies to groups receiving no pain management strategies. When possible, we also compared groups receiving one strategy to those receiving multiple strategies to see whether multiple strategies lead to more pain reduction. We looked at whether there was a difference in the impact of the interventions depending on whether the infant had just had the painful procedure (pain reactivity phase), as opposed to calming down from the peak distress (immediate pain regulation phase). 

We converted different measures of pain intensity (coded by either trained nurses or research staff) into a standard scale to help readers interpret the findings. The standard scale ranges from 0 to 21, with 0 being no pain and 21 being very severe pain. 

What did we find?

This updated Cochrane Review included 138 randomised controlled trials (trials in which participants were randomly assigned to one of two or more treatment groups) involving 11,058 participants undergoing a painful acute medical procedure. Non‐nutritive sucking, swaddling, facilitated tucking, and structured parent involvement were the four strategies most studied. 

In preterm newborns, there was evidence that non‐nutritive sucking, facilitated tucking, and swaddling may reduce pain. On the standard scale, preterm newborns receiving non‐nutritive sucking may, on average, score two points lower than preterms receiving no strategies both immediately after the painful procedure and when calming down from peak distress. Preterm newborns receiving facilitated tucking may, on average, score 3.5 points lower immediately after a painful procedure and two points lower when calming down from peak distress compared to preterms receiving no pain management strategies. While swaddling does not seem to reduce pain scores immediately after the painful procedure, swaddled preterm newborns may score, on average, four points lower than newborns receiving no strategies when calming down from distress. 

In full‐term newborns, non‐nutritive sucking may reduce pain. On the standard scale, full‐term newborns receiving non‐nutritive sucking may, on average, score four points lower immediately after a painful procedure and five points lower when calming down from peak distress compared to newborns receiving no pain management strategies.

Structured parent involvement was the strategy most studied in full‐term born older infants, but evidence showed that this strategy likely has little to no pain reduction effect in this age group. 

Adverse events were very rare across these strategies. Following non‐nutritive sucking, one preterm newborn vomited and one full‐term newborn had lower oxygen levels. No adverse events occurred following swaddling, facilitated tucking, or structured parent involvement. 

What are the limitations of the evidence?

The results of this review are based on very uncertain evidence. Many studies were too small or there were not enough studies on particular interventions to be certain about the results for our outcomes. There was also inconsistency across studies because the administration of non‐pharmacological interventions varied widely across trials in different settings. Many studies also used methods likely to introduce errors in their results. Overall, none of the analyses presented here were based on enough evidence to allow us to draw firm conclusions (i.e. high‐certainty studies from at least two independent research groups).

How up‐to‐date is the evidence?

This review is based on evidence up until October 2020. The search for studies was updated up to July 2022 and 33 eligible studies are awaiting assessment and will be incorporated in to a future update of this review.

Author(s)

Rebecca R Pillai Riddell, Oana Bucsea, Ilana Shiff, Cheryl Chow, Hannah G Gennis, Shaylea Badovinac, Miranda DiLorenzo-Klas, Nicole M Racine, Sara Ahola Kohut, Diana Lisi, Kara Turcotte, Bonnie Stevens, Lindsay S Uman

Reviewer's Conclusions

Authors' conclusions 

Implications for practice 

Implications for care‐givers of infants in pain

We examined 24 different pain management interventions that utilised cognitive, behavioural, and contextual care‐giving strategies. We analysed 18 of these interventions separately for three different infant development stages (preterm born, full‐term neonate, older infants) and two different phases post‐acute painful procedure (reactivity and immediate regulation). One of the strengths of this review was that we divided the outcomes into three developmental stages within infancy and toddlerhood. Therefore, ill and/or premature babies are a group to themselves as there are notable differences related to reactivity and variability within this population. Specifically, ill and/or premature infants exhibit more subtle facial actions when signalling their pain‐related distress. To address this issue with pain assessment in preterms, we allowed for multidimensional pain measures in our review (behaviour and physiology) that are most commonly used clinically and have demonstrated good psychometric properties for preterm procedural pain (i.e. PIPP). In addition, some research has suggested divergence between behaviour, cardiac, and cortical measurements. Future work should be dedicated to integrating cortical measurements into clinical pain practice and understanding the circumstances contributing to the divergence of different types of pain measures.

Certainty in the findings was ascertained. While many strategies appeared to show some promise in reducing pain behaviours, none of the pain management strategies supported a rating of high certainty in their findings. Most evidence had very low to low certainty in the estimate of the findings. We highlight the interventions based on the most substantial body of literature and least heterogeneity below.

Preterm born neonates                       

Pain reactivity

Non‐nutritive sucking and facilitated tucking show the most promise for reducing pain reactivity in preterms, although this is based on an evidence base with very low certainty. 

Immediate pain regulation

Non‐nutritive sucking, swaddling, and facilitated tucking show the most promise for improving immediate pain regulation in preterms, although this is based on an evidence base with very low certainty. 

Full‐term born neonates                          

Pain reactivity and immediate pain regulation

Overall, non‐nutritive sucking showed the most promise for reducing pain behaviours in both pain phases for full‐term neonates, based on an evidence base with very low certainty.

Full‐term born older infants             

Pain reactivity and immediate pain regulation

Overall, structured parent involvement was the intervention most studied, and thus based on the most substantial body of evidence, in older infants. This evidence suggests that this intervention probably results in little to no difference in reducing pain behaviours in full‐term older infants. However, a pattern emerged such that this intervention appeared to be efficacious in older groups of infants within this category (i.e. 18 months), but not in younger infants (i.e. six to eight months). 

Due to the ethical considerations with the implementation of no‐treatment control groups, more research has emerged on additive trials. Based on the randomised controlled trials (RCTs) that were completed, we made decisions to coarsely cluster the additive effects of any non‐pharmacological strategies onto three types of 'base' strategies: sweet solutions, non‐nutritive sucking, and swaddling. While that allowed for a preliminary understanding of additive effects, the heterogeneity of interventions that were collapsed in this category limits the ability to discuss the additive effect of any non‐pharmacological intervention. As more RCTs examining the same combinations of interventions emerge in the field, a clearer picture of the enhanced efficacy of additive trials across age groups and pain phases will be obtained. We expect this to be an important trend in future trials, with a complete cessation of no‐treatment control pain management RCTs. With the above caveats in mind, it does appear that in preterm infants additive effects are evident when adding a non‐pharmacological intervention on top of a sweet solution or on top of non‐nutritive sucking.

Implications for policymakers

The data continue to strengthen the evidence base regarding unmitigated pain exposure with both young children who are hospitalised or not. This review provides a comprehensive inventory of strategies that should be considered for neonatal intensive care unit (NICU) or clinic practice guidelines on acutely painful procedures.

Implications for funders of the interventions

Funding agencies should examine proposals for new RCTs for non‐pharmacological interventions (e.g. touch‐related interventions, light reduction, and multisensory bundles) within the context of our specific methodological recommendations and the critical gaps that currently exist in the literature, which have been elucidated in this review.  Examples of key gaps are whether non‐nutritive sucking works for older infants, examining the role of rocking and holding in preterm infants, and why distraction and parent involvement are not effective in older infants/toddlers (contrary to what would be predicted by theory and practice in the acute pain context). Given the strength of the additive effect of sucrose, more research should be done to understand the impact of combining pharmacological and non‐pharmacological methods (e.g. sucrose and topical anaesthetics) on reducing infant pain.

  • No‐treatment controls or inert controls (e.g. swallowing water) are now unethical in studies for infant pain and should not be used in any RCT methodology for pain.
  • Future areas of non‐pharmacological approaches to managing infant pain research should therefore focus on increasing the quality of trials and either superiority trials (e.g. which of these two interventions are better), intervention trials requiring novel combinations, better implementation of existing interventions, and empowering parents with better soothing behaviours. For more detail read below in Implications for research.

Implications for research 

Based on the results of this review, important gaps in the existing literature on non‐pharmacological management of acute pain in young children are apparent. Amongst the gaps, the highest priority for researchers are suggested below.

  • None of the findings in this review are based on high confidence in the evidence. Greater attention must be paid to CONSORT reporting and the principles that subsume high‐quality trials. In addition to better reporting, there is a fundamental challenge relating to risk of bias scores in non‐pharmacological trials (e.g. how could one blind health professionals or behavioural coders to a child being given a soother or not). Future trials could be targeted (and explicit) in their attempts to mitigate these inherent biases by measuring factors that subsume health professional personnel bias (e.g. time to complete procedure, health professional affect, health professional time touching or verbalisations to infant during procedure) or outcome assessor bias (e.g. coders blinded to study hypotheses, having two coder teams (reliable with each other) code each arm). This would also require risk of bias tools being adapted to give 'credit' for credible attempts to mitigate these specific biases. To address these risk of bias nuances, future updates of this review will use Cochrane's RoB 2 tool. 
  • Unfortunately, the interventions that showed the most promise based on the most substantial body of literature were also based on uncertain or very uncertain evidence. This suggests that there should be a greater priority for high‐quality trials on these interventions: non‐nutritive sucking, swaddling, and facilitated tucking. Despite 138 trials in this review and many trials showing positive effects, few strategies could be recommended for pain management with moderate to high confidence in the evidence.
  • Several interventions (e.g. massage/touch‐based interventions across all ages, such as traditional massage or applying pressure to the procedure site; exposure to various soothing sounds in preterms, such as maternal voice or white noise) also emerged as potentially having a pain‐reducing effect; however, the evidence base for these interventions was very heterogenous, precluding us from drawing stronger conclusions about their effectiveness. As such, more high‐quality studies are needed on these interventions to build a more substantial evidence base. 
  • Structured care‐giver interventions (parent and non‐parent) need to be informed by attachment theory (Bowlby 1982). Over the first year of life, it has been argued that the care‐giver is the most important context for infants (Pillai Riddell 2009). Currently, studies that have attempted to formally structure parent behaviour have been limited and shown to be ineffective. It should be stressed that more work on better types of parent/non‐parent interventions, especially ones that capitalise on an infant’s primary developmental need for proximity to the parent (Bowlby 1982), is needed. Teaching care‐givers to better meet an infant’s attachment needs during times of pain may lead to more efficacious parent interventions. Parents are critical to understanding infant pain responses.
  • The lack of effects on distraction may be due to methodological challenges in the administration of distraction. Distraction is suggested to be best enacted after the peak distress has passed and the child's eyes are opened. Thus, while toy distraction was found to be not effective (with moderate confidence), it is recommended that greater attention be placed on examining the timing of the distraction.
  • Very few interventions were examined in healthy older infants. Given increasing publicity surrounding vaccination refusal and the importance of vaccination in a pandemic context, it is important to examine ways to reduce pain in this age group.
  • As aforementioned, a growing aspect of the review, based on changing trends in methodology and the ethical consideration of no‐treatment control trials, is the concept of 'additive' studies. As the field moves towards examining additive instead of no‐treatment control trials, future reviews should examine the additive effects of non‐pharmacological interventions on top of specific pharmacological interventions, such as topical anaesthetics (Bourdier 2019) or sucrose (Stevens 2016a). 
  • Observational research in a large longitudinal study that used latent class analysis techniques to analyse infant pain responses over time, substantiates the assertion that there are different subgroups of pain responders (Pillai Riddell 2013b), which render average pain estimates (i.e. the key outcome in most non‐pharmacological trials for acute pain) challenging to interpret due to the inherent variability within a group, particularly in the regulation phase. Using covariates such as attachment relationship, temperament or contextual factors is critical to move the field forward.
  • The current review solely focused on behavioural indicators of pain as these are most commonly used in clinical trials. In the future, cortical responses to pain are considered by researchers to be a leading potential indicator specific to pain‐related distress (Pillai Riddell 2016). However, current infant clinical pain assessment tools have not yet incorporated this dimension. Some research has demonstrated a link between behavioural and cortical pain indicators, however this association is highly influenced by context. The relationship between brain and behaviour have been found dependent on maternal positioning (Jones 2020), stress levels (Jones 2017), and post‐sucrose administration (Slater 2010). Therefore, infant pain assessment researchers must continue to improve the outcome measures used in pain management intervention trials and incorporating contextual influences.                          

In conclusion, reflecting on this update, the largest challenge with the literature is not the quantity of studies but rather the confidence in the work that has been done. To increase the confidence of findings, one approach for the next review update is to move forward without low‐quality trials. However, this would mean omitting most of the evidence and therefore is at odds with the mission of the review. Over the past 15 years, the team has striven to provide the most comprehensive literature synthesis possible for clinicians. Therefore, for future updates, we will continue to consider strategies to help strengthen our confidence in the evidence (i.e. the use of sub‐analyses and sensitivity analyses).

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