York-led study finds urgent need to define chronic pain in babies

Signs that an infant is experiencing chronic pain may be going unrecognized by doctors and other caregivers in hospitals due to a lack of consensus on what constitutes chronic pain in babies, according to a study led by a researcher at York University with collaborators from the Hospital for Sick Children (Sick Kids), Women’s College Hospital, Bloorview Research Institute, Toronto General Hospital and the University of Toronto.

The study, appearing online in The Journal of Pain, conducted in-depth interviews with 45 master clinicians at university-affiliated hospitals with a median of 17 years experience to determine the best way to define and assess chronic pain in hospitalized infants, some born as young as 23 weeks gestation.

Right: Rebecca Pillai Riddell

Despite the lack of any formal training or guidelines about how to assess and treat it, the clinicians overwhelmingly agreed that infants are capable of experiencing chronic pain – a new development in the field since there is currently no formal definition of chronic pain in infants, said lead author Rebecca Pillai Riddell, a psychology professor in York’s Faculty of Health. Pillai Riddell runs York’s Opportunities to Understand Childhood Hurt Laboratory (OUCH Lab) and is an associate scientist in the Sick Kids’ Department of Psychiatry Research.

"One of the only ways to identify chronic pain in adults is to ask a person. There are often no clinical markers for chronic pain; there is no blood test, for example," Pillai Riddell says. "With these ill infants who can’t verbalize their experience and who often have low energy reserves after being in pain for long periods of time, we have to rely on different cues than have been established in response to acute pain, such as a needle stick."

The clinicians agreed that reactions such as the inability to settle, social withdrawal, constant grimacing, tense body, extreme or indifferent reactions to acute pain and problems with sleep and feeding, may indicate chronic pain.

But they were evenly split about whether long periods of persistent pain from repetitive exposure to painful procedures, such as needles – which may be the case for extremely premature infants – should be considered chronic pain.

It is important to parse the difference between prolonged pain that results from time-limited procedures such as surgeries and continuing pain that results from disorders such as short gut syndrome, says Pillai Riddell, noting that there are different approaches to treating different kinds of pain.

"Would you want to keep a baby that you keep poking with a needle, for example, on a constant morphine drip? No, I would rather see them being treated pre-emptively with an analgesic before each painful procedure and afterwards if needed," she says. "But I would want to see a baby with short gut syndrome, where I think the pain is pretty constant, on a more steady pain management regime."

Pillai Riddell says there is an urgent need to define chronic pain in infants so that clinicians can use proper and consistent measurements to assess and treat the pain, and help alleviate their prolonged suffering, regardless of the cause. "I suspect that, just as an adult would, babies initially have a strong reaction to painful procedures but they eventually shut down and become conditioned to the fact that even if they cry, they still get the pain from the IV or the surgery or the underlying disease.

"This is really a serious gap in our system," says Pillai Riddell. "Infants who may be in the most pain may be among the least reactive. Doctors or nurses may be interpreting that lack of response as the baby not being in pain, when it could be opposite."

"Chronic Pain in Hospitalized Infants: Health Professionals’ Perspectives" can be found online at The Journal of Pain Web site.

Pillai Riddell is the recipient of the the Canadian Pain Society’s 2009 Early Career Award in honour of her understanding of neonatal and infant pain and the role of psychosocial factors. For more on Pillai Riddell and her research, see YFile, March 4.