Analgesia for skin-breaking procedures in newborns and children: what works best?

ealthy newborns routinely experience acute pain during blood sampling for metabolic screening, injection of vitamin K or hepatitis vaccine, or circumcision. Children are similarly exposed to acute pain due to vaccination , invasive procedures or trauma. Acute pain caused by skin-breaking procedures can lead to physiologic instability and behavioural distress, and it has downstream effects on subsequent pain processing, development and stress respon-sivity. 1–5 Because of these detrimental effects, reduction or prevention of pain are worthy clinical goals that are also expected by most parents. 6,7 Opioids, such as fentanyl and morphine, form the mainstay of pediatric pain management, but they may not be effective against injury-induced acute pain in newborns or children. Accumulating data suggest that opioids lead to harmful side effects, tolerance and possibly altered brain development. 10 Other analgesic and anesthetic agents also appear to increase brain cell death in animal studies, 11,12 fuelling concerns about their use, particularly in newborns. Such concerns have led to the development of nonpharmacologic therapies such as sucrose, massage and kangaroo care for neonatal pain, and distraction techniques, hypnosis and cognitive-behavioural interventions for pediatric pain. In this issue of CMAJ, 2 randomized controlled trials evaluate the efficacy of sucrose given orally and a topical coolant spray for reducing acute pain due to skin-breaking procedures. Taddio and colleagues 13 report that sucrose reduced pain caused by venipuncture in term newborns of diabetic and nondiabetic mothers. However, sucrose did not reduce pain caused by intramuscular injections or heel lance. Farion and colleagues 14 report that the use of a vapocoolant spray reduced pain caused by intravenous cannulation and was associated with increased success in the first attempt at cannulation. The interventions in both studies had a fairly modest effect size with wide confidence intervals, which implies considerable variability in the responses to skin injury and analgesia. Both trials were well designed and had several features that support the validity of their conclusions. These investigations suggest that not every type of analgesic works for every procedure, patient, disease or age group. For nonpharmacologic interventions , it is not their ease of use, low cost or fast onset that will determine their ultimate role in the treatment of pediatric pain. Instead, their use will be determined by their efficacy compared with systemic analgesics and local anesthetics. Farion and colleagues 14 describe a rapid, convenient method for reducing the acute pain caused by intravenous cannulation; however, …