Pain, and its treatment, continues to be an unsolved mystery for
many children and their care providers.
However, during the last
6 years we have increased our understanding of how pain in early
life differs to that in maturity using a mixture of approaches from
basic science, clinical science, and implementation science that is
reflected in the 62 chapters of this second edition of the Oxford
Textbook of Pediatric Pain.
This new knowledge paints an exciting
landscape on strategies to prevent and/or ameliorate pain for the
children and families who suffer needless pain, and for healthcare
providers, decision-makers, policymakers, and all those engaged in
solving the mysteries of pain.
From basic science, we have an increasing appreciation of the role
of non-neuronal cells in mediating pain responses in early life.
We
have increased our understanding of the role of glia in spinal pain
processing in early life and have begun to understand how these
macrophage-like cells are fundamentally unique—undergoing
markedly different phenotypic shifts than adult microglia.
In early
life, these cells mount largely anti-inflammatory responses rather
than the proinflammatory ones seen in later life. Further research
is emerging to understand the way in which this response occurs.
We are also becoming more aware of the lifelong consequences
of pain in early life on the physiological response of individuals.
We
have known for some time that clinically induced painful injury can
alter sensory thresholds in later life and have recently learned that
this is also true in laboratory animals, thus allowing for the investigation of the mechanisms that underpin it.
We have learned that
global hypoalgesia following early life injury results from changes
in the maturation of the descending pain control pathways from
the brainstem and we have also seen how early life injury can
“prime” microglia to alter their response to injury much later in life.
Finally, we continue to learn more about the role of the brain in perceiving and modulating pain responses.
The last 20 years have seen
quantum leaps in our understanding of how the neonatal human
brain perceives and processes tactile and painful information.
Recently, we have seen how the areas of the brain that process sensory and affective components of pain in early life are very similar
to those in the adult (with notable exceptions of the amygdala and
orbitofrontal cortex), how brainstem pain control pathways function in early life to modulate pain perception, and how ensembles
of neurons in the sensory cortices differentially encode noxious information versus adults.
From clinical science, we have seen how hospitalized neonates
and infants continue to be exposed to multiple painful procedures
daily and how each exposure to a painful event has both immediate and long-term consequences.
Though we witness exponential
expansion in the production and synthesis of evidence supporting
the implementation of pharmacological, behavioral, and physical
approaches to pain reduction, these strategies continue to be inconsistently applied. There have been reports where assessment is
occurring in less than one-third of Neonatal Intensive Care Unit
admissions and daily in only 10% of neonates.
In the developing
world, there continues to be reports of daily painful procedures
such as peripheral cannula insertion and intramuscular injections
with almost no infants receiving any analgesia.
Of a multitude of
validated infant pain assessment tools, and guidelines stipulating
their use, consistent pain assessment—as a basis for treatment—is
still severely lacking.
Similarly, pain management for procedural
pain, despite rigorous systematic reviews, remains less than optimal, with many effective treatments being omitted from caregiving.
Continuous and persistent pain in infants remains poorly
defined, assessed, and treated.
Hospitalized older children continue to undergo painful procedures for diagnostic and treatment purposes, often without optimal
pain assessment or treatment.
Studies indicate that up to a third of
patients representing all age groups experience pain in the previous
24 hours, with about a quarter reporting moderate-to-severe pain.
The majority of children in moderate-to-severe pain did not have
a documented pain assessment, and evidence-based pharmacological and/or integrative (“nonpharmacological”) measures were
not systematically administered to prevent or treat pain.
Also, one
in five children suffers from some form of chronic pain without
sufficient access to system-wide resources, resulting in the costs of
treatment-seeking adolescents with moderate-to-severe chronic
pain upwardof US$20 billion annually in the US alone.
The explosion of clinical research that incorporates multiple
methodological approaches and patient and family perspectives has
continued to expand our knowledge of pain, and pain prevention
and treatment, with notable advances in both acute and chronic
pain.
We are also learning the importance of the influence of culture and diversity in relation to pain assessment and treatment.
Our
understanding of the factors that may increase risk for the development of chronic pain, including adverse childhood events, gives us
new targets for intervention.
There has been a growth in research
of web-based e-health interventions to allow youth to access pain
self-management strategies, pain education, and cognitive behavioral therapies closer to home.
There has been notable improvement
in the use of multimodal pharmacological therapies in hospitalized
children and youth with chronic pain (e.g., regional techniques, and
use of adjunctive medications such as ketamine and lidocaine), as
well as integrated pain management.
From implementation science, we now know that immediate uptake of new knowledge is challenging, and poor pain outcomes may
be significant owing to implementation and dissemination issues,
as compared to the generation of knowledge itself.
The theoretical
underpinnings of knowledge translation are explored in this edition, and the mobilization of new knowledge is considered at the
individual (e.g., child and family) and organizational (e.g., hospital,
healthcare system, and societal) levels.
We have learned from implementation science that the organizational context in which implementation and dissemination of new knowledge takes place, as
well as the effectiveness of the facilitation strategy, is extremely important.
Modifiable contextual factors such as leadership support,
organizational culture, and communication all play an important
role in implementing new knowledge for practice.
Over the past six years, the landscape of pain in children, the research that supports it, and prevention and treatment strategies have
grown exponentially.
The revised 2020 IASP definition of pain states
that “verbal description is only one of several behaviors to express
pain”, thus making it possible for all humans, including very young
children to experience pain.
The scientific basis of pediatric pain is
constantly expanding creating escalating excitement, but it is still
woefully inadequate. Pediatric pain treatment is more integrated
into health care rather than isolated in pain specialists; with the engagement of children, and family and professional caregivers.
In this
second edition of the book, we will not only update the status of current knowledge from basic and clinical science and practice, but we
will also focus on how that knowledge-to-practice gap is addressed
through individual and organizational implementation and facilitation strategies.
This new knowledge is a call to action given that pain
in children and youth is common and impacts many dimensions of
children’s and families’ lives.
It is our role to advocate for improved
awareness, increased knowledge, better recognition, effective treatment, and implementation of knowledge regarding pediatric pain .
